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This database contains references to published papers and abstracts from physical geographers at the University of Oregon. Sort the list using search words in the column headings. Updated October 2017.

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    BibTeX-Key Author (e.g., Gavin, Bartlein, Silva, etc) Title Year Journal / Proceedings / Book BibTeX type Keywords
    bartlein_underlying_2017 Bartlein, P.J.; Harrison, S.P. & Izumi, K. Underlying causes of Eurasian midcontinental aridity in simulations of mid-Holocene climate 2017 Geophysical Research Letters
    Vol. 44 (17) , pp. 2017GL074476  
    article 0473 paleoclimatology and paleoceanography, 3337 global climate models, 3344 paleoclimatology, cmip5/pmip3, data-model comparison, eurasia, mid-holocene, paleoclimate
    Abstract: Climate model simulations uniformly show drier and warmer summers in the Eurasian midcontinent during the mid-Holocene, which is not consistent with paleoenvironmental observations. The simulated climate results from a reduction in the zonal temperature gradient, which weakens westerly flow and reduces moisture flux and precipitation in the midcontinent. As a result, sensible heating is favored over evaporation and latent heating, resulting in substantial surface-driven atmospheric warming. Thus, the discrepancy with the paleoenvironmental evidence arises initially from a problem in the simulated circulation and is exacerbated by feedback from the land surface. This region is also drier and warmer than indicated by observations in the preindustrial control simulations, and this bias arises in the same way: zonal flow and hence moisture flux into the midcontinent are too weak, and feedback from the land surface results in surface-driven warming. These analyses suggest the need to improve those aspects of climate models that affect the strength of westerly circulation.
    BibTeX:
    @article{bartlein_underlying_2017,
      author = {Bartlein, Patrick J. and Harrison, Sandy P. and Izumi, Kenji},
      title = {Underlying causes of Eurasian midcontinental aridity in simulations of mid-Holocene climate},
      journal = {Geophysical Research Letters},
      year = {2017},
      volume = {44},
      number = {17},
      pages = {2017GL074476},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/2017GL074476/abstract},
      doi = {http://doi.org/10.1002/2017GL074476}
    }
    					
    carter_1500-year_2017 Carter, V.A.; Power, M.J.; Lundeen, Z.J.; Morris, J.L.; Petersen, K.L.; Brunelle, A.; Anderson, R.S.; Shinker, J.J.; Turney, L.; Koll, R. & Bartlein, P.J. A 1,500-year synthesis of wildfire activity stratified by elevation from the U.S. Rocky Mountains 2017 Quaternary International   article charcoal, climate, fire, paleofire, rocky mountains
    Abstract: A key task in fire-climate research in the western United States is to characterize potential future fire-climate linkages across different elevational gradients. Using thirty-seven sedimentary charcoal records, here we present a 1500-year synthesis of wildfire activity across different elevational gradients to characterize fire-climate linkages. From our results, we have identified three periods of elevated fire occurrence centered on the 20th century, 900 cal yr BP, and 1350 cal yr BP. During the 20th century, fire activity has occurred primarily in the northern Rocky Mountains, with mid-elevations experiencing the greatest increase in wildfire activity. While wildfires occurred primarily in the SRM region ca. 900 cal yr BP, the greatest increase in high-elevations occurred in the NRM at this time. Finally, synchronous wildfires occurred in both northern and southern Rocky Mountain mid-elevations ca. 1350 cal yr BP, suggesting a potential analog for future wildfire conditions in response to warmer temperatures and more protracted droughts. We conclude that wildfire activity increased in most elevations during periods of protracted summer drought, warmer-than-average temperatures, and based on modern climate analogs, reduced atmospheric humidity.
    BibTeX:
    @article{carter_1500-year_2017,
      author = {Carter, Vachel A. and Power, Mitchell J. and Lundeen, Zachary J. and Morris, Jesse L. and Petersen, Kenneth L. and Brunelle, Andrea and Anderson, R. Scott and Shinker, Jacqueline J. and Turney, Lovina and Koll, Rebecca and Bartlein, Patrick J.},
      title = {A 1,500-year synthesis of wildfire activity stratified by elevation from the U.S. Rocky Mountains},
      journal = {Quaternary International},
      year = {2017},
      url = {http://www.sciencedirect.com/science/article/pii/S1040618216315919},
      doi = {http://doi.org/10.1016/j.quaint.2017.06.051}
    }
    					
    daniels_charting_2017 Daniels, S. & Bartlein, P.J. Charting Time 2017 Annals of the American Association of Geographers
    Vol. 107 (1) , pp. 28-32  
    article chronology, cronología, lentes zoom del tiempo–espacio, narración, narration, perspectiva temporal, repeat photography, repetición de fotografía, temporal perspective, time–space zoom lens,...
    Abstract: We discuss two shared elements in the temporal perspective of human and physical geography—chronology and narration. An example of the use of these elements is in practice provided by repeat photography, a technique used in both subdisciplines, but these elements also are deployed in the development of the theories that shape the fields. We argue that their role in enhancing the “telling of temporal and spatial stories” can contribute to the resolution of issues beyond what is usually thought of as the domain of academic geography.
    BibTeX:
    @article{daniels_charting_2017,
      author = {Daniels, Stephen and Bartlein, Patrick J.},
      title = {Charting Time},
      journal = {Annals of the American Association of Geographers},
      year = {2017},
      volume = {107},
      number = {1},
      pages = {28--32},
      url = {http://dx.doi.org/10.1080/24694452.2016.1230420},
      doi = {http://doi.org/10.1080/24694452.2016.1230420}
    }
    					
    fonstad_mountains:_2017 Fonstad, M.A. Mountains: A Special Issue 2017 Annals of the American Association of Geographers
    Vol. 107 (2) , pp. 235-237  
    article cambio ambiental, coupled human–environment systems, environmental change, montaĖas, mountains, region, región, sistema, sistemas humano-ambientales acoplados, system, ...
    Abstract: The special issues of the Annals allow the editors to highlight themes of international significance that showcase the breadth and depth of geography in a format accessible to a broad array of readers. This ninth special issue of the Annals of the AAG focuses on mountains. The understanding of mountain environments and peoples has been a focus of individual geographers for centuries and for the organized discipline of geography for more than a century; more recently, the geographical interest in mountain regions among researchers has been growing rapidly. The articles contained within are from a wide spectrum of researchers from different parts of the world who address physical, political, theoretical, social, empirical, environmental, methodological, and economic issues focused on the geography of mountains and their inhabitants. The articles in this special issue are organized into three themed sections with very loose boundaries between themes: (1) physical dynamics of mountain environments, (2) coupled human–physical dynamics, and (3) sociocultural dynamics in mountain regions.
    BibTeX:
    @article{fonstad_mountains:_2017,
      author = {Fonstad, Mark A.},
      title = {Mountains: A Special Issue},
      journal = {Annals of the American Association of Geographers},
      year = {2017},
      volume = {107},
      number = {2},
      pages = {235--237},
      url = {http://dx.doi.org/10.1080/24694452.2016.1260898},
      doi = {http://doi.org/10.1080/24694452.2016.1260898}
    }
    					
    herring_ecological_2017 Herring, E.M.; Gavin, D.G.; Dobrowski, S.Z.; Fernandez, M. & Hu, F.S. Ecological history of a long-lived conifer in a disjunct population 2017 Journal of Ecology , pp. n/a-n/a   article climate, disjunction, dispersal, holocene, idaho, palaeoecology, pollen, refugia, tsuga mertensiana
    Abstract: * In northern Idaho (USA), more than 100 vascular plant species are disjunct textgreater160 km from their main distribution along the Pacific Northwest coast. It remains unclear whether most species within this interior forest disjunction, including Tsuga mertensiana, survived the last glacial period in a north-Idaho refugium or whether these species colonized the region via long-distance dispersal during the Holocene.

    * Sediment cores were extracted from three mid- to high-elevation lakes within T. mertensiana-dominated forests in the Northern Rocky Mountains of Idaho. Pollen and macrofossils were used to reconstruct forest composition, determine the timing of T. mertensiana establishment, examine the hypothesis that the region was a glacial refugium, and contrast how climate, competition and/or dispersal limitation have influenced its modern distribution.

    * The modern distribution of T. mertensiana was analysed by constructing a range map and modelling the potential species distribution. The presence of outlier populations surrounding the Idaho disjunction along with broad areas of unoccupied suitable habitat indicates that the range of T. mertensiana is currently expanding. To assess the accuracy of T. mertensiana pollen at detecting its range limit, a network of pollen surface samples was used to analyse the probability of detecting T. mertensiana pollen as a function of distance from its geographical range limit. Consistent T. mertensiana pollen occurrence at ≥1% abundance is likely only within 42 km of its range limit.

    * Tsuga mertensiana first appears in the pollen and macrofossil record at the highest-elevation site at c. 4,100 cal year bp, then at the next highest-elevation site at c. 1,600 cal year bp, and last at the mid-elevation site at 800 cal year bp. Tsuga mertensiana pollen occurs continuously at ≥1% at all three sites by c. 300 cal year bp suggesting regional presence. The timing of arrival suggests that T. mertensiana is a recent component of the forests of Idaho, having arrived during the Holocene via long-distance dispersal from coastal populations over 160 km away.

    * Synthesis. Comparison with palaeoclimate reconstructions from the broader region suggests that climate was a greater limiting factor than dispersal in the Holocene establishment in the interior, indicating little difficulty overcoming a large dispersal barrier. However, T. mertensiana remained at low abundances for millennia until Little Ice Age climates promoted its recent increase in abundance. Unoccupied areas of suitable habitat suggest that competition, rather than climate or dispersal, is a limiting range infilling in the interior mesic forests today.

    BibTeX:
    @article{herring_ecological_2017,
      author = {Herring, Erin M. and Gavin, Daniel G. and Dobrowski, Solomon Z. and Fernandez, Matias and Hu, Feng Sheng},
      title = {Ecological history of a long-lived conifer in a disjunct population},
      journal = {Journal of Ecology},
      year = {2017},
      pages = {n/a--n/a},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12826/abstract},
      doi = {http://doi.org/10.1111/1365-2745.12826}
    }
    					
    jerszurki_expanding_2017 Jerszurki, D.; Souza, J.L.M. & Silva, L.C.R. Expanding the geography of evapotranspiration: An improved method to quantify land-to-air water fluxes in tropical and subtropical regions 2017 PLOS ONE
    Vol. 12 (6) , pp. e0180055  
    article brazil, humidity, seasons, solar radiation, subtropical regions, summer, vapor pressure, winter
    Abstract: The development of new reference evapotranspiration (ETo) methods hold significant promise for improving our quantitative understanding of climatic impacts on water loss from the land to the atmosphere. To address the challenge of estimating ETo in tropical and subtropical regions where direct measurements are scarce we tested a new method based on geographical patterns of extraterrestrial radiation (Ra) and atmospheric water potential (Ψair). Our approach consisted of generating daily estimates of ETo across several climate zones in Brazil–as a model system–which we compared with standard EToPM (Penman-Monteith) estimates. In contrast with EToPM, the simplified method (EToMJS) relies solely on Ψair calculated from widely available air temperature (oC) and relative humidity ( data, which combined with Ra data resulted in reliable estimates of equivalent evaporation (Ee) and ETo. We used regression analyses of Ψair vs EToPM and Ee vs EToPM to calibrate the EToMJS(Ψair) and EToMJS estimates from 2004 to 2014 and between seasons and climatic zone. Finally, we evaluated the performance of the new method based on the coefficient of determination (R2) and correlation (R), index of agreement “d”, mean absolute error (MAE) and mean reason (MR). This evaluation confirmed the suitability of the EToMJS method for application in tropical and subtropical regions, where the climatic information needed for the standard EToPM calculation is absent.
    BibTeX:
    @article{jerszurki_expanding_2017,
      author = {Jerszurki, Daniela and Souza, Jorge L. M. and Silva, Lucas C. R.},
      title = {Expanding the geography of evapotranspiration: An improved method to quantify land-to-air water fluxes in tropical and subtropical regions},
      journal = {PLOS ONE},
      year = {2017},
      volume = {12},
      number = {6},
      pages = {e0180055},
      url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180055},
      doi = {http://doi.org/10.1371/journal.pone.0180055}
    }
    					
    jerszurki_impact_2017 Jerszurki, D.; Couvreur, V.; Maxwell, T.; Silva, L. d.C.R.; Matsumoto, N.; Shackel, K.; de Souza, J.L.M. & Hopmans, J. Impact of root growth and hydraulic conductance on canopy carbon-water relations of young walnut trees (Juglans regia L.) under drought 2017 Scientia Horticulturae
    Vol. 226 (Supplement C) , pp. 342-352  
    article canopy transpiration, hydraulic conductance, leaf isotopic signals, root growth
    Abstract: In addition to soil characteristics, two plant traits control the supply of water from the soil to the canopy: root growth and plant hydraulic conductance. Here we examine the impact of root growth and hydraulic conductance on water uptake and transpiration of walnut under deficit irrigation. A greenhouse experiment was conducted using nine young walnut trees (Juglans regia L.) grown for three months in transparent pots, equipped with: (i) rhizotron tubes, which allowed for non-invasive monitoring of root growth; (ii) pressure transducer tensiometers, recording soil water potential at soil-root interfaces; (iii) psychrometers attached to mature leaves, measuring stem water potential; and (iv) weighing scales used to determine total plant transpiration. Irrigation treatments consisted of different replenishment levels (100 75 and 50 of potential transpiration replicated over time. Walnut trees showed rapid physiological acclimation characterized by a fast decline and subsequent stabilization of transpiration rates soon after the beginning of drought stress treatments. We also observed a significant decrease in plant hydraulic conductance with decreasing soil and stem water potential under drought stress. At the end of the experiment, isotopic measurements revealed the integrated effect of physiological acclimation on canopy carbon-water relations. Leaf carbon isotope ratios showed significant increases in water-use efficiency with deficit irrigation levels. Leaf water hydrogen and oxygen isotope ratios confirmed that changes in water use-efficiency were caused by decreases in transpiration. Conversely, root growth was highest under low stress (T100) and lowest under high stress (T50). These results indicate the existence of a fundamental tradeoff between water-use efficiency and root growth, which will be useful to optimize the application of water and improve the design of irrigation systems in walnut orchards.
    BibTeX:
    @article{jerszurki_impact_2017,
      author = {Jerszurki, Daniela and Couvreur, Valentin and Maxwell, Toby and Silva, Lucas de Carvalho Ramos and Matsumoto, Nicholas and Shackel, Kenneth and de Souza, Jorge Luiz Moretti and Hopmans, Jan},
      title = {Impact of root growth and hydraulic conductance on canopy carbon-water relations of young walnut trees (Juglans regia L.) under drought},
      journal = {Scientia Horticulturae},
      year = {2017},
      volume = {226},
      number = {Supplement C},
      pages = {342--352},
      url = {http://www.sciencedirect.com/science/article/pii/S0304423817305216},
      doi = {http://doi.org/10.1016/j.scienta.2017.08.051}
    }
    					
    kageyama_pmip4_2017 Kageyama, M.; Albani, S.; Braconnot, P.; Harrison, S.P.; Hopcroft, P.O.; Ivanovic, R.F.; Lambert, F.; Marti, O.; Peltier, W.R.; Peterschmitt, J.-Y.; Roche, D.M.; Tarasov, L.; Zhang, X.; Brady, E.C.; Haywood, A.M.; LeGrande, A.N.; Lunt, D.J.; Mahowald, N.M.; Mikolajewicz, U.; Nisancioglu, K.H.; Otto-Bliesner, B.L.; Renssen, H.; Tomas, R.A.; Zhang, Q.; Abe-Ouchi, A.; Bartlein, P.J.; Cao, J.; Lohmann, G.; Ohgaito, R.; Shi, X.; Volodin, E.; Yoshida, K.; Zhang, X. & Zheng, W. The PMIP4 contribution to CMIP6 – Part 4: Scientific objectives and experimental design of the PMIP4-CMIP6 Last Glacial Maximum experiments and PMIP4 sensitivity experiments 2017 Geoscientific Model Development Discussions , pp. 1-33   article
    BibTeX:
    @article{kageyama_pmip4_2017,
      author = {Kageyama, Masa and Albani, Samuel and Braconnot, Pascale and Harrison, Sandy P. and Hopcroft, Peter O. and Ivanovic, Ruza F. and Lambert, Fabrice and Marti, Olivier and Peltier, W. Richard and Peterschmitt, Jean-Yves and Roche, Didier M. and Tarasov, Lev and Zhang, Xu and Brady, Esther C. and Haywood, Alan M. and LeGrande, Allegra N. and Lunt, Daniel J. and Mahowald, Natalie M. and Mikolajewicz, Uwe and Nisancioglu, Kerim H. and Otto-Bliesner, Bette L. and Renssen, Hans and Tomas, Robert A. and Zhang, Qiong and Abe-Ouchi, Ayako and Bartlein, Patrick J. and Cao, Jian and Lohmann, Gerrit and Ohgaito, Rumi and Shi, Xiaoxu and Volodin, Evgeny and Yoshida, Kohei and Zhang, Xiao and Zheng, Weipeng},
      title = {The PMIP4 contribution to CMIP6 – Part 4: Scientific objectives and experimental design of the PMIP4-CMIP6 Last Glacial Maximum experiments and PMIP4 sensitivity experiments},
      journal = {Geoscientific Model Development Discussions},
      year = {2017},
      pages = {1--33},
      url = {https://www.geosci-model-dev-discuss.net/gmd-2017-18/},
      doi = {http://doi.org/10.5194/gmd-2017-18}
    }
    					
    marshall_late_2017 Marshall, J.A.; Roering, J.J.; Gavin, D.G. & Granger, D.E. Late Quaternary climatic controls on erosion rates and geomorphic processes in western Oregon, USA 2017 Geological Society of America Bulletin
    Vol. 129 , pp. 715-731  
    article
    Abstract: Climate regulation of erosion in unglaciated landscapes remains difficult to decipher. While climate may disrupt process feedbacks that would otherwise steer landscapes toward steady erosion, sediment transport processes tend to erase past climate landforms and thus bias landscape evolution interpretations. Here, we couple a 50 k.y. paleoenvironmental record with 24 10Be-derived paleo-erosion rates from a 63-m-thick sediment archive in the unglaciated soil-mantled Oregon Coast Range. Our results span the forested marine oxygen isotope stage (MIS) 3 (50-29 ka), the subalpine MIS 2 (29-14 ka), and the forested MIS 1 (14 ka to present). From 46 ka through 28.5 ka, erosion rates increased from 0.06 mm yr-1 to 0.23 mm yr-1, coincident with declining temperatures. Mean MIS 2 erosion rates remained at 0.21 mm yr-1 and declined with increasing MIS 1 temperatures to the modern mean rate of 0.08 mm yr-1. Paleoclimate reconstructions and a frost-weathering model suggest periglacial processes were vigorous between 35 and 17 ka. While steady erosion is often assumed, our results suggest that climate strongly modulates soil production and transport on glacial-interglacial time scales. By applying a cosmogenic paleo-erosion model to evaluate 10Be concentrations in our sedimentary archive, we demonstrate that the depth of soil mixing (which is climate-dependent) controls the lag time required for cosmogenic erosion rates to track actual values. Our results challenge the widely held assumption that climate has minimal impact on erosion rates in unglaciated midlatitude terrain, which invites reconsideration of the extent to which past climate regimes manifest in modern landscapes.
    BibTeX:
    @article{marshall_late_2017,
      author = {Marshall, Jill A. and Roering, Joshua J. and Gavin, Daniel G. and Granger, Darryl E.},
      title = {Late Quaternary climatic controls on erosion rates and geomorphic processes in western Oregon, USA},
      journal = {Geological Society of America Bulletin},
      year = {2017},
      volume = {129},
      pages = {715--731},
      url = {http://gsabulletin.gsapubs.org/content/early/2017/01/27/B31509.1},
      doi = {http://doi.org/10.1130/B31509.1}
    }
    					
    morris_nitrogen_2017 Morris, J.; Ye, R.; Silva, L.C.R. & Horwath, W.R. Nitrogen Fertilization Had No Effect on CH and N O Emissions in Rice Planted in Rewetted Peatlands 2017 Soil Science Society of America Journal
    Vol. 81 (1) , pp. 224-232  
    article
    BibTeX:
    @article{morris_nitrogen_2017,
      author = {Morris, Jennifer and Ye, Rongzhong and Silva, Lucas C. R. and Horwath, William R.},
      title = {Nitrogen Fertilization Had No Effect on CH and N O Emissions in Rice Planted in Rewetted Peatlands},
      journal = {Soil Science Society of America Journal},
      year = {2017},
      volume = {81},
      number = {1},
      pages = {224--232},
      url = {https://dl.sciencesocieties.org/publications/sssaj/abstracts/81/1/224},
      doi = {http://doi.org/10.2136/sssaj2016.06.0182}
    }
    					
    schworer_holocene_2017 Schwörer, C.; Gavin, D.G.; Walker, I.R. & Hu, F.S. Holocene tree line changes in the Canadian Cordillera are controlled by climate and topography 2017 Journal of Biogeography
    Vol. 44 (5) , pp. 1148-1159  
    article pollen, palaeoecology, british columbia, vegetation history, climate change, forest dynamics, macrofossils, fire history, timberline, moisture availability
    Abstract: Aim

    Although ongoing climate change is expected to lead to an upward shift of tree lines in mountain areas, evidence for widespread tree line advances remains scarce, implying secondary controls on tree line dynamics at the local scale. We aim to determine if vegetation change in response to past warm periods was regionally synchronous or if local factors such as topography, geomorphology or fire caused divergent local responses.

    Location

    The Canadian Cordillera in south-eastern British Columbia (Canada).

    Methods

    We analysed post-glacial sediments from three lakes at or just below the present tree line for macrofossils, pollen and charcoal to infer past local forest composition, density, dynamics and fire disturbance.

    Results

    At two lakes (Windy and Redmountain), tree macrofossil concentrations were highest in the warmer-than-present Early Holocene (11,700–7000 cal. bp), indicating higher forest density and tree line position during this time period. At the third lake (Thunder), macrofossil concentrations were low during the Early Holocene and reached maximum values in the mid-Holocene (7000–3000 cal. bp). The divergent vegetation dynamics and species composition at Thunder Lake suggest that moisture availability may have limited the establishment of closed forests on steep south-facing slopes or shallow soils in the Early Holocene.

    Main conclusions

    Summer temperature was the main driver of tree line dynamics over millennial to decadal time-scales. Closed forests, however, occurred only in areas of adequate moisture availability, which is controlled by topography and geomorphology. We therefore expect a rapid upward shift of tree lines during the 21st century in response to warmer temperatures, but only where deep soils or favourable aspects provide sufficient moisture for tree growth. Upward forest expansion will therefore be patchy and occur first in favourable microsites.

    BibTeX:
    @article{schworer_holocene_2017,
      author = {Schwörer, Christoph and Gavin, Daniel G. and Walker, Ian R. and Hu, Feng Sheng},
      title = {Holocene tree line changes in the Canadian Cordillera are controlled by climate and topography},
      journal = {Journal of Biogeography},
      year = {2017},
      volume = {44},
      number = {5},
      pages = {1148--1159},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/jbi.12904/abstract},
      doi = {http://doi.org/10.1111/jbi.12904}
    }
    					
    shintani_comparing_2017 Shintani, C. & Fonstad, M.A. Comparing remote-sensing techniques collecting bathymetric data from a gravel-bed river 2017 International Journal of Remote Sensing
    Vol. 38 (8-10) , pp. 2883-2902  
    article
    Abstract: Quantifying bathymetry is essential in understanding the physical processes that control channel form and function. New applications in a wide range of disciplines have an urgent need for more continuous mapping of fluvial topography. Recent advances in through-water photogrammetry and optical imagery indicate that accurate, continuous bathymetric mapping may be possible in shallow, clear streams. This research directly compares the ability of through-water photogrammetry and spectral depth approaches to extract water depth for environmental applications. Imagery and cross sections were collected on a 140 m reach of the Salmon River in Clackamas County, Oregon, using an unmanned aerial vehicle (UAV) and real time kinematic (rtk)-GPS. Structure-from-Motion (SfM) software produced a digital elevation model (DEM) (1.5 cm) and orthophotograph (0.37 cm) derived from these data. The photogrammetric approach of applying a site-specific refractive index provided the most accurate (mean error, ME, 0.009 m) and precise (standard deviation of error, SD, 0.17 m) bathymetric data (R2 = 0.67) over the spectral depth and the 1.34 refractive index approaches. This research provides a quantitative comparison between and within bathymetric mapping methods, and suggests that a site-specific refractive index may be appropriate for similar gravel-bed, relatively shallow, clear streams.
    BibTeX:
    @article{shintani_comparing_2017,
      author = {Shintani, Christina and Fonstad, Mark A.},
      title = {Comparing remote-sensing techniques collecting bathymetric data from a gravel-bed river},
      journal = {International Journal of Remote Sensing},
      year = {2017},
      volume = {38},
      number = {8-10},
      pages = {2883--2902},
      url = {http://dx.doi.org/10.1080/01431161.2017.1280636},
      doi = {http://doi.org/10.1080/01431161.2017.1280636}
    }
    					
    silva_carbon_2017 Silva, L.C.R. Carbon sequestration beyond tree longevity 2017 Science
    Vol. 355 (6330) , pp. 1141-1141  
    article
    Abstract: The effect of atmospheric CO2 on tree growth and terrestrial carbon stocks has been the subject of much debate. In his Perspective “A matter of tree longevity” (13 January, p. [130][1]), C. Körner argued that faster tree growth does not increase carbon storage because carbon is inevitably
    BibTeX:
    @article{silva_carbon_2017,
      author = {Silva, Lucas C. R.},
      title = {Carbon sequestration beyond tree longevity},
      journal = {Science},
      year = {2017},
      volume = {355},
      number = {6330},
      pages = {1141--1141},
      url = {http://science.sciencemag.org/content/355/6330/1141},
      doi = {http://doi.org/10.1126/science.aan0109}
    }
    					
    sperling_temperature_2017 Sperling, O.; Silva, L.C.R.; Tixier, A.; Théroux-Rancourt, G. & Zwieniecki, M.A. Temperature gradients assist carbohydrate allocation within trees 2017 Scientific Reports
    Vol. 7  
    article
    Abstract: Trees experience two distinct environments: thermally-variable air and thermally-buffered soil. This generates intra-tree temperature gradients, which can affect carbon metabolism and water transport. In this study, we investigated whether carbohydrate allocation within trees is assisted by temperature gradients. We studied pistachio (Pistacia integerrima) to determine: (1) temperature-induced variation in xylem sugar concentration in excised branches; (2) changes in carbon allocation in young trees under simulated spring and fall conditions; and (3) seasonal variability of starch levels in mature orchard trees under field conditions. We found that warm branches had less sugar in perfused sap than cold branches due to increasing parenchyma storage. Simulated spring conditions promoted allocation of carbohydrates from cold roots to warm canopy and explained why starch levels surged in canopies of orchard trees during early spring. This driving force of sugar transport is interrupted in fall when canopies are colder than roots and carbohydrate redistribution is compartmentalized. On the basis of these findings, we propose a new mechanistic model of temperature-assisted carbohydrate allocation that links environmental cues and tree phenology. This data-enabled model provides insights into thermal “fine-tuning” of carbohydrate metabolism and a warning that the physiological performance of trees might be impaired by climatic changes.
    BibTeX:
    @article{sperling_temperature_2017,
      author = {Sperling, Or and Silva, Lucas C. R. and Tixier, Aude and Théroux-Rancourt, Guillaume and Zwieniecki, Maciej A.},
      title = {Temperature gradients assist carbohydrate allocation within trees},
      journal = {Scientific Reports},
      year = {2017},
      volume = {7},
      url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5468369/},
      doi = {http://doi.org/10.1038/s41598-017-03608-w}
    }
    					
    walther_geographic_2017 Walther, S.C.; Reinholtz, A.L. & Marcus, W.A. The geographic distribution of small dams in Oregon using ecoregion and landform classification 2017 Physical Geography
    Vol. 38 (3) , pp. 286-301  
    article distributions, ecoregions, oregon, small dams
    Abstract: Small dams fragment river landscapes, disrupting channel connectivity and impacting water quality and quantity. Although they impound volumetrically less total water than large dams, the ubiquity of small dams suggests their cumulative impacts could be significant. Documenting the distribution and characteristics of small dams is necessary to understanding and mitigating their impacts. In this study, we compare datasets of small dams in Oregon, compile a new comprehensive dataset, and document geographic variations in small dam distributions between different ecoregions. We used Oregon Water Resources Department dam and Oregon Department of Fish and Wildlife fish passage barrier datasets to compare dam heights and contributing drainage areas between different ecoregions. Over 61% of Oregon’s land area is above one or more small dam. We highlight the location of Oregon’s small dams at valley margins, transition zones between flat plains and mountains, and areas of high population density. Given the hidden nature of small dams, evaluation of small dam impacts using public imagery is not effective. However, knowledge of small dam distributions given their association with landforms can aid in finding unrecorded dams, assessing approaches for evaluating their geomorphic impacts, and informing their management.
    BibTeX:
    @article{walther_geographic_2017,
      author = {Walther, Suzanne C. and Reinholtz, Amanda L. and Marcus, W. Andrew},
      title = {The geographic distribution of small dams in Oregon using ecoregion and landform classification},
      journal = {Physical Geography},
      year = {2017},
      volume = {38},
      number = {3},
      pages = {286--301},
      url = {http://dx.doi.org/10.1080/02723646.2017.1286224},
      doi = {http://doi.org/10.1080/02723646.2017.1286224}
    }
    					
    winsome_plant-microbe_2017 Winsome, T.; Silva, L.C.R.; Scow, K.M.; Doane, T.A.; Powers, R.F. & Horwath, W.R. Plant-microbe interactions regulate carbon and nitrogen accumulation in forest soils 2017 Forest Ecology and Management
    Vol. 384 , pp. 415-423  
    article biodiversity, nutrient cycling, soil organic matter, sustainability
    Abstract: Understory removal is a common practice in forest plantations, which is aimed at reducing competition for resources and increasing the productivity of target tree species. Recent studies have shown, however, that the presence of understory vegetation can increase soil carbon and nutrient content, especially where N-fixing species are present. To investigate whether this response can be attributed to changes in soil microbial communities, we conducted experiments with isotopically-labeled litter in Pinus ponderosa stands where N-fixing understory species were present (UP) or absent (UA). We measured carbon and nutrient stocks and monitored changes in soil microbial biomass and composition. Field and laboratory experiments strongly suggest that understory suppression and relatively small changes in litter quality can yield significant changes in soil C and N stocks, which are critical to maintaining forest productivity. We detected a greater accumulation of carbon and nitrogen (relative to controls) when mixtures of pine and N-rich litter were applied to the soil. In contrast, soils amended only with pine litter showed a net loss of carbon and nitrogen stocks. Soil microbial biomass was significantly higher in UP than in UA stands and microbial community composition varied with type of litter inputs and incubation time (0–180 days), but not as a function of understory management. Similar results were obtained from field experiments, in which mesocosms were incubated for ca. 2.5 years with pine and N-rich understory litter mixtures. The suppression of understory species caused a decline in litter-derived carbon and nitrogen in the soil, even when the microbial community was resilient to the imposed treatments.
    BibTeX:
    @article{winsome_plant-microbe_2017,
      author = {Winsome, Thaēs and Silva, Lucas C. R. and Scow, Kate M. and Doane, Timothy A. and Powers, Robert F. and Horwath, William R.},
      title = {Plant-microbe interactions regulate carbon and nitrogen accumulation in forest soils},
      journal = {Forest Ecology and Management},
      year = {2017},
      volume = {384},
      pages = {415--423},
      url = {http://www.sciencedirect.com/science/article/pii/S0378112716308039},
      doi = {http://doi.org/10.1016/j.foreco.2016.10.036}
    }
    					
    wortham_assessing_2017 Wortham, B.E.; Wong, C.I.; Silva, L.C.R.; McGee, D.; MontaĖez, I.P.; Troy Rasbury, E.; Cooper, K.M.; Sharp, W.D.; Glessner, J.J.G. & Santos, R.V. Assessing response of local moisture conditions in central Brazil to variability in regional monsoon intensity using speleothem 87Sr/86Sr values 2017 Earth and Planetary Science Letters
    Vol. 463 , pp. 310-322  
    article holocene, south american summer monsoon, stable isotopes, strontium isotopes
    Abstract: Delineating the controls on hydroclimate throughout Brazil is essential to assessing potential impact of global climate change on water resources and biogeography. An increasing number of monsoon reconstructions from d18O records provide insight into variations in regional monsoon intensity over the last millennium. The strength, however, of d18O as a proxy of regional climate limits its ability to reflect local conditions, highlighting the need for comparable reconstructions of local moisture conditions. Here, speleothem 87Sr/86Sr values are developed as a paleo-moisture proxy in central Brazil to complement existing d18O-based reconstructions of regional monsoon intensity. Speleothem 87Sr/86Sr values are resolved using laser ablation and conventional solution mass spectrometry at high resolution relative to existing (non-d18O-based) paleo-moisture reconstructions to allow comparisons of centennial variability in paleo-monsoon intensity and paleo-moisture conditions. Variations in speleothem 87Sr/86Sr values from Tamboril Cave are interpreted to reflect varying extents of water interaction with the carbonate host rock, with more interaction resulting in greater evolution of water isotope values from those initially acquired from the soil to those of the carbonate bedrock. Increasing speleothem 87Sr/86Sr values over the last millennium suggest progressively less interaction with the carbonate host rock likely resulting from higher infiltration rates, expected under wetter conditions. Increasingly wetter conditions over the last millennium are consistent with an overall trend of increasing monsoon intensity (decreasing d18O values) preserved in many existing δ18O records from the region. Such a trend, however, is absent in d18O records from our site (central Brazil) and Cristal Cave (southeast Brazil), suggesting the existence of divergent (relevant to d18Oprecip) shifts in the climate patterns within and outside the core monsoon region.
    BibTeX:
    @article{wortham_assessing_2017,
      author = {Wortham, Barbara E. and Wong, Corinne I. and Silva, Lucas C. R. and McGee, David and MontaĖez, Isabel P. and Troy Rasbury, E. and Cooper, Kari M. and Sharp, Warren D. and Glessner, Justin J. G. and Santos, Roberto V.},
      title = {Assessing response of local moisture conditions in central Brazil to variability in regional monsoon intensity using speleothem 87Sr/86Sr values},
      journal = {Earth and Planetary Science Letters},
      year = {2017},
      volume = {463},
      pages = {310--322},
      url = {http://www.sciencedirect.com/science/article/pii/S0012821X17300468},
      doi = {http://doi.org/10.1016/j.epsl.2017.01.034}
    }
    					
    dawson_second_2016 Dawson, M.N.; Axmacher, J.C.; Beierkuhnlein, C.; Blois, J.L.; Bradley, B.A.; Cord, A.F.; Dengler, J.; He, K.S.; Heaney, L.R.; Jansson, R.; Mahecha, M.D.; Myers, C.; Nogués-Bravo, D.; Papadopoulou, A.; Reu, B.; Rodríguez-Sánchez, F.; Steinbauer, M.J.; Stigall, A.; Tuanmu, M.-N. & Gavin, D.G. A second horizon scan of biogeography: Golden Ages, Midas touches, and the Red Queen 2016 Frontiers of Biogeography
    Vol. 8 (4)  
    article
    Abstract: Are we entering a new ‘Golden Age’ of biogeography, with continued development of infrastructure and ideas? We highlight recent developments, and the challenges and opportunities they bring, in light of the snapshot provided by the 7th biennial meeting of the International Biogeography Society (IBS 2015). We summarize themes in and across 15 symposia using narrative analysis and word clouds, which we complement with recent publication trends and ‘research fronts’. We find that biogeography is still strongly defined by core sub-disciplines that reflect its origins in botanical, zoological (particularly bird and mammal), and geographic (e.g., island, montane) studies of the 1800s. That core is being enriched by large datasets (e.g. of environmental variables, ‘omics’, species’ occurrences, traits) and new techniques (e.g., advances in genetics, remote sensing, modeling) that promote studies with increasing detail and at increasing scales; disciplinary breadth is being diversified (e.g., by developments in paleobiogeography and microbiology) and integrated through the transfer of approaches and sharing of theory (e.g., spatial modeling and phylogenetics in evolutionary–ecological contexts). Yet some subdisciplines remain on the fringe (e.g., marine biogeography, deep-time paleobiogeography), new horizons and new theory may be overshadowed by popular techniques (e.g., species distribution modelling), and hypotheses, data, and analyses may each be wanting. Trends in publication suggest a shift away from traditional biogeography journals to multidisciplinary or open access journals. Thus, there are currently many opportunities and challenges as biogeography increasingly addresses human impacts on, and stewardship of, the planet (e.g., Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services). As in the past, biogeographers doubtless will continue to be engaged by new data and methods in exploring the nexus between biology and geography for decades into the future. But golden ages come and go, and they need not touch every domain in a discipline nor affect subdisciplines at the same time; moreover, what appears to be a Golden Age may sometimes have an undesirable ‘Midas touch’. Contexts within and outwith biogeography—e.g., methods, knowledge, climate, biodiversity, politics—are continually changing, and at times it can be challenging to establish or maintain relevance. In so many races with the Red Queen, we suggest that biogeography will enjoy greatest success if we also increasingly engage with the epistemology of our discipline.
    BibTeX:
    @article{dawson_second_2016,
      author = {Dawson, Michael N. and Axmacher, Jan C. and Beierkuhnlein, Carl and Blois, Jessica L. and Bradley, Bethany A. and Cord, Anna F. and Dengler, Jürgen and He, Kate S. and Heaney, Lawrence R. and Jansson, Roland and Mahecha, Miguel D. and Myers, Corinne and Nogués-Bravo, David and Papadopoulou, Anna and Reu, Björn and Rodríguez-Sánchez, Francisco and Steinbauer, Manuel J. and Stigall, Alycia and Tuanmu, Mao-Ning and Gavin, Daniel G.},
      title = {A second horizon scan of biogeography: Golden Ages, Midas touches, and the Red Queen},
      journal = {Frontiers of Biogeography},
      year = {2016},
      volume = {8},
      number = {4},
      url = {http://escholarship.org/uc/item/8bx638kb},
      doi = {http://doi.org/10.21425/F58429770}
    }
    					
    de_farias_survival_2016 de Farias, J.; Marimon, B.S.; de Carvalho Ramos Silva, L.; Petter, F.A.; Andrade, F.R.; Morandi, P.S. & Marimon-Junior, B.H. Survival and growth of native Tachigali vulgaris and exotic Eucalyptus urophylla x Eucalyptus grandis trees in degraded soils with biochar amendment in southern Amazonia 2016 Forest Ecology and Management
    Vol. 368 (Supplement C) , pp. 173-182  
    article biomass, black carbon, deforestation, reforestation
    Abstract: The impact of agricultural and livestock activities on tropical forests often results in long-lasting damage to soil and vegetation. In undisturbed tropical forests, nutrient stocks tend to be larger in the aboveground biomass than in the soil profile; therefore, deforested sites may remain bare for decades due to nutrient limitation. In such circumstance, amelioration of edaphic conditions and planting of tree species adapted to open canopy conditions (pioneers) could help restore ecosystem functions while providing a sustainable source of timber and prompting natural succession. The aim of this study was to evaluate the use of biochar as a soil amendment that could accelerate the reforestation of degraded lands. We used a randomized block design with five treatments and four replications, comparing the performance of exotic eucalyptus (Eucalyptus urophylla x Eucalyptus grandis) and native Tachigali vulgaris trees. We monitored reforested plots for 49months, evaluating tree survival and growth rates, litter production, canopy cover and density of invasive grasses. The addition of biochar in the soil did not result in significant differences in tree survival or productivity when compared to controls. Comparing the two species, native trees (T. vulgaris) performed better by all metrics, showing 52% survival and producing 241.7Mgha-1 of aboveground biomass after four years of growth. During that same period the survival rate of eucalyptus was 38% and the aboveground productivity was only 82.4Mgha-1. In contrast with eucalyptus plantations, T. vulgaris showed rapid canopy cover and completely suppressed invasive grasses, generating up to 11.7Mgha-1 more litter than eucalyptus trees. Although eucalyptus is one of the most commonly used species in reforestation for timber, charcoal, and pulp and paper production in Brazil, our results demonstrate that T. vulgaris has the potential to replace eucalyptus in commercial plantations with the added benefit of being a native species that can promote the establishment of a stable forest cover in degraded sites.
    BibTeX:
    @article{de_farias_survival_2016,
      author = {de Farias, Josenilton and Marimon, Beatriz Schwantes and de Carvalho Ramos Silva, Lucas and Petter, Fabiano André and Andrade, Fabrício Ribeiro and Morandi, Paulo Sérgio and Marimon-Junior, Ben Hur},
      title = {Survival and growth of native Tachigali vulgaris and exotic Eucalyptus urophylla x Eucalyptus grandis trees in degraded soils with biochar amendment in southern Amazonia},
      journal = {Forest Ecology and Management},
      year = {2016},
      volume = {368},
      number = {Supplement C},
      pages = {173--182},
      url = {http://www.sciencedirect.com/science/article/pii/S0378112716300901},
      doi = {http://doi.org/10.1016/j.foreco.2016.03.022}
    }
    					
    de_oliveira_bomfim_effect_2016 De Oliveira Bomfim, B.; Silva, L.C.R.; Horwath, W.R.; Hello, J. & Doane, T.A. The Effect of Land-use Change and Management on Free-living N2 fixation in the Brazilian Atlantic Forest 2016 AGU Fall Meeting Abstracts
    Vol. 53  
    inproceedings 0402 agricultural systems, and modeling, biogeosciences, biogeosciencesde: 0414 biogeochemical cycles, biogeosciencesde: 0428 carbon cycling, biogeosciencesde: 0470 nutrients and nutrient cycling, processes
    Abstract: Globally, primary tropical forests are increasingly disturbed by
    deforestation, urbanization, agriculture, and cattle ranching. It has
    been recognized that the resulting (secondary) forests now play a key
    role in global biogeochemical cycles; however, little is known about
    alterations in forest function caused by the combination of disturbance
    and land use change. Fire, deforestation, and forest-to-monocrop
    conversion are all likely to affect biotic N inputs, yet our
    understanding of how free-living N2 fixation influences ecosystem
    response after disturbance remains poorly understood. Our research is
    assessing the role of asymbiotic (free-living) biological nitrogen
    fixation (BNF), a microbially-mediated process responsible for providing
    N inputs across terrestrial ecosystems and modulating the effect of fire
    and land cover in secondary forest succession. Free-living BNF is being
    quantified through incubations using stable isotope (15N2 labeling
    experiment) in different substrates (soil and leaf litter) under
    contrasting land use and management in the Brazilian Atlantic Forest,
    the most deforested Biome in Brazil with only 7% of its original cover.
    Soil and litter samples were collected in primary forests, 12-year
    secondary forests, Eucalyptus spp. plantations and 10-year Brachiaria
    brizantha pastures. Preliminary results indicate that free-living BNF
    rates did not vary significantly between either secondary land use (0.02
    to 0.46 Ķg N2 fixed gDW-1 h-1), but rates were significantly
    higher in the litter layer (0.32 to 3.8 Ķg N2 fixed gDW-1 h-1)
    than in the surface soil (0 - 10 cm and 10 - 30 cm). Free-living BNF in
    this stretch of the Brazilian Atlantic Forest seems not to be
    significantly affected by contrasting land use and management.
    BibTeX:
    @article{de_oliveira_bomfim_effect_2016,
      author = {De Oliveira Bomfim, B. and Silva, L. C. R. and Horwath, W. R. and Hello, J. and Doane, T. A.},
      title = {The Effect of Land-use Change and Management on Free-living N2 fixation in the Brazilian Atlantic Forest},
      journal = {AGU Fall Meeting Abstracts},
      year = {2016},
      volume = {53},
      url = {http://adsabs.harvard.edu/abs/2016AGUFM.B53M..08D}
    }
    					
    dietrich_climatic_2016 Dietrich, R.; Bell, F.W.; Silva, L.C.R.; Cecile, A.; Horwath, W.R. & Anand, M. Climatic sensitivity, water-use efficiency, and growth decline in boreal jack pine (Pinus banksiana) forests in Northern Ontario 2016 Journal of Geophysical Research: Biogeosciences
    Vol. 121 (10) , pp. 2016JG003440  
    article 3305 climate change and variability, 4870 stable isotopes, 4920 dendrochronology, carbon fertilization, dendrochronology, stable isotope analysis, tree rings
    Abstract: Rises in atmospheric carbon dioxide (atmCO2) levels are known to stimulate photosynthesis and increase intrinsic water-use efficiency (iWUE) in trees. Stand-level increases in iWUE depend on the physiological response of dominant species to increases in atmCO2, while tree-level response to increasing atmCO2 depends on the balance between the direct effects of atmCO2 on photosynthetic rate and the indirect effects of atmCO2 on drought conditions. The aim of this study was to characterize the response of boreal jack pine (Pinus banksiana) stands in Northern Ontario to changes in atmCO2 and associated climatic change over the past 100 years. The impact of changes in growing season length, temperature, and precipitation, as well as atmCO2 on tree growth, was determined using stable carbon isotopes and dendrochronological analysis. Jack pine stands in this study were shown to be in progressive decline. As expected, iWUE was found to increase in association with rising atmCO2. However, increases in iWUE were not directly coupled with atmCO2, suggesting that the degree of iWUE improvement is limited by alternative factors. Water-use efficiency was negatively associated with tree growth, suggesting that warming- and drought-induced stomatal closure has likely led to deviations from expected atmCO2-enhanced growth. This finding corroborates that boreal forest stands are likely to face continued stress under future climatic warming.
    BibTeX:
    @article{dietrich_climatic_2016,
      author = {Dietrich, Rachel and Bell, F. Wayne and Silva, Lucas C. R. and Cecile, Alice and Horwath, William R. and Anand, Madhur},
      title = {Climatic sensitivity, water-use efficiency, and growth decline in boreal jack pine (Pinus banksiana) forests in Northern Ontario},
      journal = {Journal of Geophysical Research: Biogeosciences},
      year = {2016},
      volume = {121},
      number = {10},
      pages = {2016JG003440},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/2016JG003440/abstract},
      doi = {http://doi.org/10.1002/2016JG003440}
    }
    					
    dietrich_riverscape_2016 Dietrich, J.T. Riverscape mapping with helicopter-based Structure-from-Motion photogrammetry 2016 Geomorphology
    Vol. 252 (Supplement C) , pp. 144-157  
    article fluvial geomorphology, fluvial remote sensing, middle fork john day river, multi-view stereo photogrammetry, structure-from-motion (sfm)
    Abstract: Recent developments in the remote sensing of fluvial systems have provided researchers with unprecedented views on the complexity of rivers. An aerial perspective is key to mapping and understanding the river at a variety of spatial scales. I employed a helicopter-mounted digital SLR camera and Structure-from-Motion (SfM) photogrammetry to bridge the gap between smaller scale aerial surveys from platforms like small unmanned aerial systems and larger scale commercial aerial photography or airborne LiDAR collections. This low-cost solution produced high spatial resolution aerial photography and digital elevation models for a 32-km segment of the Middle Fork John Day River in east central Oregon. Using these data, I extracted channel morphology data at 3-m intervals downstream and took an inductive approach to evaluating the controls on channel morphology and the human influences on the river using a combination of segment-scale and hyperscale analyses. The SfM process produced 10cm/pixel orthophotographs and DEMs with submeter horizontal accuracy, but the DEMs suffered from a systematic distortion that resulted from the parallel camera geometry of the flight plan. The riverscape has been affected by human actions such as mining, cattle grazing, and restoration; however, differentiating a human signal from the natural patterns of channel morphology was difficult. The hyperscale analysis provided insight into several interesting downstream patterns in channel morphology that, with further analysis, could provide explanations on the physical controls of channel morphology. Overall, SfM has the potential to be a powerful, low-cost addition to the fluvial remote sensing toolkit.
    BibTeX:
    @article{dietrich_riverscape_2016,
      author = {Dietrich, James T.},
      title = {Riverscape mapping with helicopter-based Structure-from-Motion photogrammetry},
      journal = {Geomorphology},
      year = {2016},
      volume = {252},
      number = {Supplement C},
      pages = {144--157},
      url = {http://www.sciencedirect.com/science/article/pii/S0169555X15002627},
      doi = {http://doi.org/10.1016/j.geomorph.2015.05.008}
    }
    					
    harrison_what_2016 Harrison, S.P.; Bartlein, P.J. & Prentice, I.C. What have we learnt from palaeoclimate simulations? 2016 Journal of Quaternary Science
    Vol. 31 (4) , pp. 363-385  
    article climate reconstruction, cmip5, forward modelling, palaeoclimate modelling, palaeoenvironmental data synthesis
    Abstract: There has been a gradual evolution in the way that palaeoclimate modelling and palaeoenvironmental data are used together to understand how the Earth System works, from an initial and largely descriptive phase through explicit hypothesis testing to diagnosis of underlying mechanisms. Analyses of past climate states are now regarded as integral to the evaluation of climate models, and have become part of the toolkit used to assess the likely realism of future projections. Palaeoclimate assessment has demonstrated that changes in large-scale features of climate that are governed by the energy and water balance show consistent responses to changes in forcing in different climate states, and these consistent responses are reproduced by climate models. However, state-of-the-art models are still largely unable to reproduce observed changes in climate at a regional scale reliably. While palaeoclimate analyses of state-of-the-art climate models suggest an urgent need for model improvement, much work is also needed on extending and improving palaeoclimate reconstructions and quantifying and reducing both numerical and interpretative uncertainties.
    BibTeX:
    @article{harrison_what_2016,
      author = {Harrison, Sandy P. and Bartlein, Patrick J. and Prentice, I. Colin},
      title = {What have we learnt from palaeoclimate simulations?},
      journal = {Journal of Quaternary Science},
      year = {2016},
      volume = {31},
      number = {4},
      pages = {363--385},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/jqs.2842/abstract},
      doi = {http://doi.org/10.1002/jqs.2842}
    }
    					
    hoffman_13000_2016 Hoffman, K.M.; Gavin, D.G.; Lertzman, K.P.; Smith, D.J. & Starzomski, B.M. 13,000 years of fire history derived from soil charcoal in a British Columbia coastal temperate rain forest 2016 Ecosphere
    Vol. 7 (7) , pp. n/a-n/a  
    article british columbia, pacific northwest, radiocarbon dating, soil charcoal, holocene fire history, coastal temperate rain forest, human–climate–fire interactions
    Abstract: Little is known regarding the fire history of high-latitude coastal temperate rain forests in the Pacific Northwest (PNW) of North America. While reconstructing historical fire regimes typically requires dendrochronological records from fire-scarred trees or stratigraphically preserved lake sediment data, this type of information is virtually non-existent in this region. To describe the long-term fire history of a site on the central coast of British Columbia, Canada, we radiocarbon-dated 52 pieces of charcoal. Charcoal ages ranged from 12,670 to 70 yr BP. Fires occurred regularly since 12,670 yr BP, with the exception of a distinct fire-free period at 7500–5500 yr BP. Time since fire (TSF) estimates from soil charcoal and fire-scarred trees ranged from 12,670 to 100 yr BP (median = 327 yr), and 70% of the sites examined had burned within the past 1000 yr. An increase in fire frequency in the late Holocene is consistent with the widely held hypothesis that anthropogenic fires were common across the PNW. We evaluate TSF distributions and discuss the difficulties in assigning actual fire dates from charcoal fragments with large inbuilt ages in a coastal temperate rain forest setting. We determine that a comprehensive approach using soil charcoal and fire scar analyses is necessary to reconstruct general trends in fire activity throughout the Holocene in this region.
    BibTeX:
    @article{hoffman_13000_2016,
      author = {Hoffman, K. M. and Gavin, D. G. and Lertzman, K. P. and Smith, D. J. and Starzomski, B. M.},
      title = {13,000 years of fire history derived from soil charcoal in a British Columbia coastal temperate rain forest},
      journal = {Ecosphere},
      year = {2016},
      volume = {7},
      number = {7},
      pages = {n/a--n/a},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/ecs2.1415/abstract},
      doi = {http://doi.org/10.1002/ecs2.1415}
    }
    					
    hoffman_seven_2016 Hoffman, K.M.; Gavin, D.G. & Starzomski, B.M. Seven hundred years of human-driven and climate-influenced fire activity in a British Columbia coastal temperate rainforest 2016 Royal Society Open Science
    Vol. 3 (10) , pp. 160608  
    article
    Abstract: While wildland fire is globally most common at the savannah-grassland ecotone, there is little evidence of fire in coastal temperate rainforests. We reconstructed fire activity with a ca 700-year fire history derived from fire scars and stand establishment from 30 sites in a very wet (up to 4000 mm annual precipitation) temperate rainforest in coastal British Columbia, Canada. Drought and warmer temperatures in the year prior were positively associated with fire events though there was little coherence of climate indices on the years of fires. At the decadal scale, fires were more likely to occur after positive El NiĖo-Southern Oscillation and Pacific Decadal Oscillation phases and exhibited 30-year periods of synchrony with the negative phase of the Arctic Oscillation. Fire frequency was significantly inversely correlated with the distance from former Indigenous habitation sites and fires ceased following cultural disorganization caused by disease and other European impacts in the late nineteenth century. Indigenous people were likely to have been the primary ignition source in this and many coastal temperate rainforest settings. These data are directly relevant to contemporary forest management and discredit the myth of coastal temperate rainforests as pristine landscapes.
    BibTeX:
    @article{hoffman_seven_2016,
      author = {Hoffman, Kira M. and Gavin, Daniel G. and Starzomski, Brian M.},
      title = {Seven hundred years of human-driven and climate-influenced fire activity in a British Columbia coastal temperate rainforest},
      journal = {Royal Society Open Science},
      year = {2016},
      volume = {3},
      number = {10},
      pages = {160608},
      url = {http://rsos.royalsocietypublishing.org/content/3/10/160608},
      doi = {http://doi.org/10.1098/rsos.160608}
    }
    					
    izumi_north_2016 Izumi, K. & Bartlein, P.J. North American paleoclimate reconstructions for the Last Glacial Maximum using an inverse modeling through iterative forward modeling approach applied to pollen data 2016 Geophysical Research Letters
    Vol. 43 (20) , pp. 2016GL070152  
    article 0424 biosignatures and proxies, 0473 paleoclimatology and paleoceanography, 1620 climate dynamics, inverse-vegetation modeling, pollen-based climate reconstruction, the last glacial maximum
    Abstract: The inverse modeling through iterative forward modeling (IMIFM) approach was used to reconstruct Last Glacial Maximum (LGM) climates from North American fossil pollen data. The approach was validated using modern pollen data and observed climate data. While the large-scale LGM temperature IMIFM reconstructions are similar to those calculated using conventional statistical approaches, the reconstructions of moisture variables differ between the two approaches. We used two vegetation models, BIOME4 and BIOME5-beta, with the IMIFM approach to evaluate the effects on the LGM climate reconstruction of differences in water use efficiency, carbon use efficiency, and atmospheric CO2 concentrations. Although lower atmospheric CO2 concentrations influence pollen-based LGM moisture reconstructions, they do not significantly affect temperature reconstructions over most of North America. This study implies that the LGM climate was very cold but not very much drier than present over North America, which is inconsistent with previous studies.
    BibTeX:
    @article{izumi_north_2016,
      author = {Izumi, Kenji and Bartlein, Patrick J.},
      title = {North American paleoclimate reconstructions for the Last Glacial Maximum using an inverse modeling through iterative forward modeling approach applied to pollen data},
      journal = {Geophysical Research Letters},
      year = {2016},
      volume = {43},
      number = {20},
      pages = {2016GL070152},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/2016GL070152/abstract},
      doi = {http://doi.org/10.1002/2016GL070152}
    }
    					
    jerszurki_modeling_2016 Jerszurki, D.; Souza, J.L.M.; Silva, L.C.R. & Gurski, B.C. Modeling an Alternative Reference Evapotranspiration Method under Different Climate Regimes in Brazil 2016 AGU Fall Meeting Abstracts
    Vol. 11  
    inproceedings 1622 earth system modeling, global changede: 1818 evapotranspiration, hydrology, hydrologyde: 1855 remote sensing, hydrologyde: 1895 instruments and techniques: monitoring
    Abstract: The development and validation of new reference evapotranspiration (ETo)
    methods hold significant promise for an improved quantitative
    understanding of terrestrial water fluxes to the atmosphere. To address
    a critical gap in knowledge, concerning the general absence of adequate
    alternative ETo estimations for tropical and subtropical regions,
    generated a new reference method "Moretti-Jerszurki", based on
    atmospheric water potential (Ψair) and solar radiation (Ra) data. We
    adjusted and evaluated this physical ETo method for the most
    representative climate types of Brazil. We compared our results with
    standard EToPM (Penman-Monteith) estimates performed between 2004 and
    2014, using air temperature (T), sunshine hours (n), relative humidity
    (RH) and wind speed (U2). The new method was proposed and analyzed in
    two different scenarios, based: (i) only on Ψair (EToMJ(Ψair));
    and, (ii) Ψair and Ra (EToMJ and EToMJc). Least square regression
    analysis of Ψair vs EToPM and EToMJ vs EToPM were used to calibrate
    the EToMJ(ψair) and EToMJc methods, respectively. The performance of
    calibrated methods EToMJ(Ψair) and EToMJc was evaluated by index of
    agreement "d" and performance "c", root mean square error (RMSE), mean
    absolute error (MAE) and mean reason (MR). Preliminary results across a
    wide range of tropical and subtropical climates are promising and
    indicate a strong linear association with standard EToPM. The
    EToMJ(Ψair) was particularly robust in tropical and semi-arid
    climates, outlining the importance of continuous measurements of T and
    RH used in the Ψair modeling effort. We recommend the use of EToMJc
    for most humid climate types in the region, but simplified
    EToMJ(Ψair) estimates are better suited to estimate water fluxes in
    arid and semi-arid regions.
    BibTeX:
    @article{jerszurki_modeling_2016,
      author = {Jerszurki, D. and Souza, J. L. M. and Silva, L. C. R. and Gurski, B. C.},
      title = {Modeling an Alternative Reference Evapotranspiration Method under Different Climate Regimes in Brazil},
      journal = {AGU Fall Meeting Abstracts},
      year = {2016},
      volume = {11},
      url = {http://adsabs.harvard.edu/abs/2016AGUFM.H11B1295J}
    }
    					
    kageyama_pmip4-cmip6:_2016 Kageyama, M.; Braconnot, P.; Harrison, S.P.; Haywood, A.M.; Jungclaus, J.; Otto-Bliesner, B.L.; Peterschmitt, J.-Y.; Abe-Ouchi, A.; Albani, S.; Bartlein, P.J.; Brierley, C.; Crucifix, M.; Dolan, A.; Fernandez-Donado, L.; Fischer, H.; Hopcroft, P.O.; Ivanovic, R.F.; Lambert, F.; Lunt, D.J.; Mahowald, N.M.; Peltier, W.R.; Phipps, S.J.; Roche, D.M.; Schmidt, G.A.; Tarasov, L.; Valdes, P.J.; Zhang, Q. & Zhou, T. PMIP4-CMIP6: the contribution of the Paleoclimate Modelling Intercomparison Project to CMIP6 2016 Geoscientific Model Development Discussions (10.5194/gmd-2016-106)   article
    Abstract: The goal of the Palaeoclimate Modelling Intercomparison Project (PMIP) is to understand the response of the climate system to changes in different climate forcings and to feedbacks. Through comparison with observations of the environmental impacts of these climate changes, or with climate reconstructions based on physical,
    chemical or biological records, PMIP also addresses the issue of how well state-of-the-art models simulate climate changes. Palaeoclimate states are radically different from those of the recent past documented by the instrumental record and thus provide an out-of-sample test of the models used for future climate projections and
    a way to assess whether they have the correct sensitivity to forcings and feedbacks. Five distinctly different periods have been selected as focus for the core palaeoclimate experiments that are designed to contribute to the objectives of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). This manuscript describes
    the motivation for the choice of these periods and the design of the numerical experiments, with a focus upon their novel features compared to the experiments performed in previous phases of PMIP and CMIP as well as the benefits of common analyses of the models across multiple climate states. It also describes the information
    needed to document each experiment and the model outputs required for analysis and benchmarking.
    BibTeX:
    @article{kageyama_pmip4-cmip6:_2016,
      author = {Kageyama, Masa and Braconnot, Pascale and Harrison, Sandy P. and Haywood, Alan M. and Jungclaus, Johann and Otto-Bliesner, Bette L. and Peterschmitt, Jean-Yves and Abe-Ouchi, Ayako and Albani, Samuel and Bartlein, Patrick J. and Brierley, Chris and Crucifix, Michel and Dolan, Aisling and Fernandez-Donado, Laura and Fischer, Hubertus and Hopcroft, Peter O. and Ivanovic, Ruza F. and Lambert, Fabrice and Lunt, Dan J. and Mahowald, Natalie M. and Peltier, W. Richard and Phipps, Stephen J. and Roche, Didier M. and Schmidt, Gavin A. and Tarasov, Lev and Valdes, Paul J. and Zhang, Qiong and Zhou, Tianjun},
      title = {PMIP4-CMIP6: the contribution of the Paleoclimate Modelling Intercomparison Project to CMIP6},
      journal = {Geoscientific Model Development Discussions},
      year = {2016},
      number = {10.5194/gmd-2016-106},
      url = {http://centaur.reading.ac.uk/65722/}
    }
    					
    mason_earles_bark_2016 Mason Earles, J.; Sperling, O.; Silva, L.C.R.; McElrone, A.J.; Brodersen, C.R.; North, M.P. & Zwieniecki, M.A. Bark water uptake promotes localized hydraulic recovery in coastal redwood crown 2016 Plant, Cell & Environment
    Vol. 39 (2) , pp. 320-328  
    article embolism, fog, foliar uptake, phellem, sequoia sempervirens
    Abstract: Coastal redwood (Sequoia sempervirens), the world's tallest tree species, rehydrates leaves via foliar water uptake during fog/rain events. Here we examine if bark also permits water uptake in redwood branches, exploring potential flow mechanisms and biological significance. Using isotopic labelling and microCT imaging, we observed that water entered the xylem via bark and reduced tracheid embolization. Moreover, prolonged bark wetting (16 h) partially restored xylem hydraulic conductivity in isolated branch segments and whole branches. Partial hydraulic recovery coincided with an increase in branch water potential from about -5.5 Ī 0.4 to -4.2 Ī 0.3 MPa, suggesting localized recovery and possibly hydraulic isolation. As bark water uptake rate correlated with xylem osmotic potential (R2 = 0.88), we suspect a symplastic role in transferring water from bark to xylem. Using historical weather data from typical redwood habitat, we estimated that bark and leaves are wet more than 1000 h per year on average, with over 30 events being sufficiently long (>24 h) to allow for bark-assisted hydraulic recovery. The capacity to uptake biologically meaningful volumes of water via bark and leaves for localized hydraulic recovery throughout the crown during rain/fog events might be physiologically advantageous, allowing for relatively constant transpiration.
    BibTeX:
    @article{mason_earles_bark_2016,
      author = {Mason Earles, J. and Sperling, Or and Silva, Lucas C. R. and McElrone, Andrew J. and Brodersen, Craig R. and North, Malcolm P. and Zwieniecki, Maciej A.},
      title = {Bark water uptake promotes localized hydraulic recovery in coastal redwood crown},
      journal = {Plant, Cell & Environment},
      year = {2016},
      volume = {39},
      number = {2},
      pages = {320--328},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/pce.12612/abstract},
      doi = {http://doi.org/10.1111/pce.12612}
    }
    					
    maxwell_predictable_2016 Maxwell, T.; Silva, L.C.R. & Horwath, W.R. Predictable oxygen isotope exchange of plant lipids improves our ability to understand hydrologic shifts and partition evapotranspiration across scales 2016 AGU Fall Meeting Abstracts
    Vol. 31  
    inproceedings 3344 paleoclimatology, atmospheric processesde: 1833 hydroclimatology, hydrologyde: 4904 atmospheric transport and circulation, paleoceanography, paleoceanographyde: 4914 continental climate records
    Abstract: Understanding the partitioning of evapotranspiration is critical to
    assessing how changes in climate affect the terrestrial water cycle.
    N-alkyl lipids have been successfully used to integrate local to
    regional scale hydrologic change through the integration of δD
    measured in specific compounds found in sediments. However, such studies
    are limited compared to contemporary hydrologic studies which have the
    advantage of using dual isotope methods whereby δD and δ18O
    are used in conjunction to partition evapotranspiration. δD values
    in n-alkyl lipids have been established as resistant to exchange with
    environmental water and, this approach has allowed for routine
    measurement and reconstruction of plant water δD. In contrast, the
    use of δ18O in organic matter remains incipient because the low
    oxygen content of plant lipids makes it difficult to accurately measure
    δ18O. In the interest of addressing both fundamental and practical
    potential of a lipid δ18O proxy, we present the first evidence for
    predictable exchange of δ18O between environmental water and
    hydrophobic bulk organic matter, neutral saponified lipids, and specific
    plant derived compounds Our data suggests that these different pools may
    be used to reconstruct the original source water δD/δ18O
    relationship from soil or sedimentary organic matter, which will help
    elucidate hydrologic shifts in terrestrial systems. Our results bring
    new insight into methods by which organic compounds might be used to
    partition evapotranspiration across large spatial scales in both
    contemporary and reconstructed systems.
    BibTeX:
    @article{maxwell_predictable_2016,
      author = {Maxwell, T. and Silva, L. C. R. and Horwath, W. R.},
      title = {Predictable oxygen isotope exchange of plant lipids improves our ability to understand hydrologic shifts and partition evapotranspiration across scales},
      journal = {AGU Fall Meeting Abstracts},
      year = {2016},
      volume = {31},
      url = {http://adsabs.harvard.edu/abs/2016AGUFMPP31D2311M}
    }
    					
    otto-bleisner_pmip4_2016 Otto-Bleisner, B.L.; Braconnot, P.; Harrison, S.P.; Lunt, D.J.; Abe-Ouchi, A.; Albani, S.; Bartlein, P.J.; Capron, E.; Carlson, A.E.; Dutton, A.; Fischer, H.; Goelzer, H.; Govin, A.; Haywood, A.; Joos, F.; Legrande, A.N.; Lipscomb, W.H.; Lohmann, G.; Mahowald, N.; Nehrbass-Ahles, C.; Pausata, F.S.-R.; Peterschmidt, J.-Y.; Phipps, S. & Renssen, H. The PMIP4 contribution to CMIP6 – Part 2: two interglacials, scientific objective and experimental design for Holocene and last interglacial simulations 2016 Geoscientific Model Development Discussions (10.5194/gmd-2016-279)   article
    Abstract: Two interglacial epochs are included in the suite of Paleoclimate Modeling Intercomparison Project (PMIP4) simulations in the Coupled Model Intercomparison Project (CMIP6). The experimental protocols for Tier 1 simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127,000 years before present) are described here. These equilibrium simulations are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land-sea contrast and high-latitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional CMIP6 Tier 2 and Tier 3 sensitivity experiments of PMIP4, to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last Interglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedbacks (e.g., vegetation, dust) and the ability of state-of-the-art models to simulate climate changes realistically.
    BibTeX:
    @article{otto-bleisner_pmip4_2016,
      author = {Otto-Bleisner, Bette L. and Braconnot, Pascale and Harrison, Sandy P. and Lunt, Daniel J. and Abe-Ouchi, Ayako and Albani, Samuel and Bartlein, Patrick J. and Capron, Emilie and Carlson, Anders E. and Dutton, Andrea and Fischer, Hubertus and Goelzer, Heiko and Govin, Aline and Haywood, Alan and Joos, Fortunat and Legrande, Allegra N. and Lipscomb, William H. and Lohmann, Gerrit and Mahowald, Natalie and Nehrbass-Ahles, Christoph and Pausata, Francesco S.-R. and Peterschmidt, Jean-Yves and Phipps, Steven and Renssen, Hans},
      title = {The PMIP4 contribution to CMIP6 – Part 2: two interglacials, scientific objective and experimental design for Holocene and last interglacial simulations},
      journal = {Geoscientific Model Development Discussions},
      year = {2016},
      number = {10.5194/gmd-2016-279},
      url = {http://centaur.reading.ac.uk/68688/}
    }
    					
    schworer_modeling_2016 Schwörer, C.; Fisher, D.M.; Gavin, D.G.; Temperli, C. & Bartlein, P.J. Modeling postglacial vegetation dynamics of temperate forests on the Olympic Peninsula (WA, USA) with special regard to snowpack 2016 Climatic Change
    Vol. 137 (3-4) , pp. 379-394  
    article
    Abstract: Past and future forest composition and distribution in temperate mountain ranges is strongly influenced by temperature and snowpack. We used LANDCLIM, a spatially explicit, dynamic vegetation model, to simulate forest dynamics for the last 16,000 years and compared the simulation results to pollen and macrofossil records at five sites on the Olympic Peninsula (Washington, USA). To address the hydrological effects of climate-driven variations in snowpack on simulated forest dynamics, we added a simple snow accumulation-and-melt module to the vegetation model and compared simulations with and without the module. LANDCLIM produced realistic present-day species composition with respect to elevation and precipitation gradients. Over the last 16,000 years, simulations driven by transient climate data from an atmosphere-ocean general circulation model (AOGCM) and by a chironomid-based temperature reconstruction captured Late-glacial to Late Holocene transitions in forest communities. Overall, the reconstruction-driven vegetation simulations matched observed vegetation changes better than the AOGCM-driven simulations. This study also indicates that forest composition is very sensitive to snowpack-mediated changes in soil moisture. Simulations without the snow module showed a strong effect of snowpack on key bioclimatic variables and species composition at higher elevations. A projected upward shift of the snow line and a decrease in snowpack might lead to drastic changes in mountain forests composition and even a shift to dry meadows due to insufficient moisture availability in shallow alpine soils.
    BibTeX:
    @article{schworer_modeling_2016,
      author = {Schwörer, Christoph and Fisher, David M. and Gavin, Daniel G. and Temperli, Christian and Bartlein, Patrick J.},
      title = {Modeling postglacial vegetation dynamics of temperate forests on the Olympic Peninsula (WA, USA) with special regard to snowpack},
      journal = {Climatic Change},
      year = {2016},
      volume = {137},
      number = {3-4},
      pages = {379--394},
      url = {http://link.springer.com/article/10.1007/s10584-016-1696-z},
      doi = {http://doi.org/10.1007/s10584-016-1696-z}
    }
    					
    seely_linking_2016 Seely, T.; Shackel, K. & Silva, L.C.R. Linking Plant Water-Use Efficiency and Depth of Water Uptake to Field-Level Productivity Under Surplus and Deficit Irrigation in Almond Orchards 2016 AGU Fall Meeting Abstracts
    Vol. 51  
    inproceedings 1807 climate impacts, hydrology, hydrologyde: 1809 desertification, hydrologyde: 1813 eco-hydrology, hydrologyde: 1843 land/atmosphere interactions
    Abstract: The impact of water stress on depth of water uptake, as well as
    water-use efficiency (WUE) at the tree-level and field-level was
    examined in almond orchards under varying degrees of deficit and surplus
    irrigation treatments. Three different orchards, spanning a latitudinal
    gradient (35° to 39° N) were sampled during two growing seasons
    in the central valley of CA. The orchards encompass a range of climatic
    and edaphic conditions, providing an opportunity for comparisons of WUE
    and orchard yield under contrasting environmental conditions. In each
    orchard, the control treatment received 100% replacement of water lost
    to evapotranspiration (ET), while the surplus treatment received 110br>and the deficit treatment received 70% replenishment of ET, the latter
    simulating conditions of water stress. Preliminary results based on the
    analysis of carbon isotope ratios (δ13C) in leaves throughout the
    2015 and 2016 growing seasons, reveal a significant change in WUE in all
    three orchard sites, increasing up to 20% on average in the deficit
    irrigation treatment relative to controls. In contrast, trees growing
    under surplus irrigation had the lowest WUE across all orchard sites.
    The difference in WUE between surplus irrigated trees and control
    irrigated trees within each orchard was not always statistically
    significant. These physiological responses to levels of water
    availability were not reflected in field-level orchard productivity,
    which was highly variable across orchard sites and treatments.
    Additionally, analysis of oxygen (δ18O) and hydrogen (δ2H)
    isotope ratios of stem, leaf, and soil water has been undertaken to
    determine the effect of water stress on the depth of root water uptake.
    The hypothesis that almond trees can effectively acclimate to water
    stress through higher WUE and deeper root water uptake compared to
    well-watered trees will be tested. This multi-scale, ecohydrological
    study will elucidate the impacts of drought on almond orchards, one of
    the most water-intensive crops in California, as well as other
    tree-dominated systems.
    BibTeX:
    @article{seely_linking_2016,
      author = {Seely, T. and Shackel, K. and Silva, L. C. R.},
      title = {Linking Plant Water-Use Efficiency and Depth of Water Uptake to Field-Level Productivity Under Surplus and Deficit Irrigation in Almond Orchards},
      journal = {AGU Fall Meeting Abstracts},
      year = {2016},
      volume = {51},
      url = {http://adsabs.harvard.edu/abs/2016AGUFM.H51G1571S}
    }
    					
    shafer_lpj-guess_2016 Shafer, S.L. & Bartlein, P.J. LPJ-GUESS Simulated North America Vegetation for 21-0 ka Using the TraCE-21ka Climate Simulation 2016 AGU Fall Meeting Abstracts
    Vol. 53  
    inproceedings 4299 general or miscellaneous, oceanography: generalde: 4999 general or miscellaneous, paleoceanography
    Abstract: Transient climate simulations that span multiple millennia (e.g.,
    TraCE-21ka) have become more common as computing power has increased,
    allowing climate models to complete long simulations in relatively short
    periods of time (i.e., months). These climate simulations provide
    information on the potential rate, variability, and spatial expression
    of past climate changes. They also can be used as input data for other
    environmental models to simulate transient changes for different
    components of paleoenvironmental systems, such as vegetation. Long,
    transient paleovegetation simulations can provide information on a range
    of ecological processes, describe the spatial and temporal patterns of
    changes in species distributions, and identify the potential locations
    of past species refugia. Paleovegetation simulations also can be used to
    fill in spatial and temporal gaps in observed paleovegetation data
    (e.g., pollen records from lake sediments) and to test hypotheses of
    past vegetation change. We used the TraCE-21ka transient climate
    simulation for 21-0 ka from CCSM3, a coupled atmosphere-ocean general
    circulation model. The TraCE-21ka simulated temperature, precipitation,
    and cloud data were regridded onto a 10-minute grid of North America.
    These regridded climate data, along with soil data and atmospheric
    carbon dioxide concentrations, were used as input to LPJ-GUESS, a
    general ecosystem model, to simulate North America vegetation from 21-0
    ka. LPJ-GUESS simulates many of the processes controlling the
    distribution of vegetation (e.g., competition), although some important
    processes (e.g., dispersal) are not simulated. We evaluate the
    LPJ-GUESS-simulated vegetation (in the form of plant functional types
    and biomes) for key time periods and compare the simulated vegetation
    with observed paleovegetation data, such as data archived in the Neotoma
    Paleoecology Database. In general, vegetation simulated by LPJ-GUESS
    reproduces the major North America vegetation patterns (e.g., forest,
    grassland) with regional areas of disagreement between simulated and
    observed vegetation. We describe the regions and time periods with the
    greatest data-model agreement and disagreement, and discuss some of the
    strengths and weaknesses of both the simulated climate and simulated
    vegetation data.
    BibTeX:
    @article{shafer_lpj-guess_2016,
      author = {Shafer, S. L. and Bartlein, P. J.},
      title = {LPJ-GUESS Simulated North America Vegetation for 21-0 ka Using the TraCE-21ka Climate Simulation},
      journal = {AGU Fall Meeting Abstracts},
      year = {2016},
      volume = {53},
      url = {http://adsabs.harvard.edu/abs/2016AGUFMPP53A2380S}
    }
    					
    sheil_how_2016 Sheil, D.; Ladd, B.; Silva, L.C.R.; Laffan, S.W. & Heist, M.V. How are soil carbon and tropical biodiversity related? 2016 Environmental Conservation
    Vol. 43 (3) , pp. 231-241  
    article carbon stocks, conservation, detritus, organic matter, peat, redd, tropical forests, wetlands
    Abstract: SUMMARY
    This article discusses how biological conservation can benefit from an understanding of soil carbon. Protecting natural areas not only safeguards the biota but also curtails atmospheric carbon emissions. Opportunities for funding biological conservation could potentially be greater if soil carbon content is considered. In this article current knowledge concerning the magnitude and vulnerability of soil carbon stocks is reviewed and the relationship of these stocks to biological conservation values is explored. Looking at two relatively well-studied tropical regions we find that 15 of 21 animal species of conservation concern in the Virunga Landscape (Central Africa), and nine of ten such species in the Federal District of Brazil (Central Brazil), rely on carbon-rich habitats (alluvial and/or wetlands). At national scales, densities of species, endemics and threatened taxa (plants, mammals, birds, reptiles, amphibians and fish) show positive and significant relations with mean soil carbon content in all but two cases (threatened amphibians and threatened fish). Of more than 1000 threatened species in 37 selected tropical nations, 85% rely on carbon-rich habitats. This tendency is observed in plants, mammals, reptiles, amphibians and crustaceans, while birds appear more evenly distributed. Research to clarify and explore these relationships is needed. Soil carbon offers major opportunities for conservation.
    BibTeX:
    @article{sheil_how_2016,
      author = {Sheil, Douglas and Ladd, Brenton and Silva, Lucas C. R. and Laffan, Shawn W. and Heist, Miriam Van},
      title = {How are soil carbon and tropical biodiversity related?},
      journal = {Environmental Conservation},
      year = {2016},
      volume = {43},
      number = {3},
      pages = {231--241},
      url = {https://www.cambridge.org/core/journals/environmental-conservation/article/how-are-soil-carbon-and-tropical-biodiversity-related/7B37B842C250C95AB080CEAFBEACE38C},
      doi = {http://doi.org/10.1017/S0376892916000011}
    }
    					
    silva_tree_2016 Silva, L.C.R.; Sun, G.; Zhu-Barker, X.; Liang, Q.; Wu, N. & Horwath, W.R. Tree growth acceleration and expansion of alpine forests: The synergistic effect of atmospheric and edaphic change 2016 Science Advances
    Vol. 2 (8) , pp. e1501302  
    article
    Abstract: Many forest ecosystems have experienced recent declines in productivity; however, in some alpine regions, tree growth and forest expansion are increasing at marked rates. Dendrochronological analyses at the upper limit of alpine forests in the Tibetan Plateau show a steady increase in tree growth since the early 1900s, which intensified during the 1930s and 1960s, and have reached unprecedented levels since 1760. This recent growth acceleration was observed in small/young and large/old trees and coincided with the establishment of trees outside the forest range, reflecting a connection between the physiological performance of dominant species and shifts in forest distribution. Measurements of stable isotopes (carbon, oxygen, and nitrogen) in tree rings indicate that tree growth has been stimulated by the synergistic effect of rising atmospheric CO2 and a warming-induced increase in water and nutrient availability from thawing permafrost. These findings illustrate the importance of considering soil-plant-atmosphere interactions to understand current and anticipate future changes in productivity and distribution of forest ecosystems.
    Soil-plant-atmosphere interactions regulate the impact of climate on forest ecosystems.
    Soil-plant-atmosphere interactions regulate the impact of climate on forest ecosystems.
    BibTeX:
    @article{silva_tree_2016,
      author = {Silva, Lucas C. R. and Sun, Geng and Zhu-Barker, Xia and Liang, Qianlong and Wu, Ning and Horwath, William R.},
      title = {Tree growth acceleration and expansion of alpine forests: The synergistic effect of atmospheric and edaphic change},
      journal = {Science Advances},
      year = {2016},
      volume = {2},
      number = {8},
      pages = {e1501302},
      url = {http://advances.sciencemag.org/content/2/8/e1501302},
      doi = {http://doi.org/10.1126/sciadv.1501302}
    }
    					
    wortham_potential_2016 Wortham, B.E.; Wong, C.I.; McGee, D.; Rasbury, T.; Silva, L.C.R.; Montanez, I.P.; Cooper, K.M.; Sharp, W.D. & Tappa, M.J. Potential decoupling between the regional monsoon intensity and local moisture conditions during the last millennium in central Brazil 2016 AGU Fall Meeting Abstracts
    Vol. 24  
    inproceedings 1616 climate variability, global change, global changede: 1630 impacts of global change, global changede: 1637 regional climate change, global changede: 1655 water cycles
    Abstract: Reconstructing moisture variability throughout the tropics is essential
    to assessing recurrent droughts and the response of hydroclimate to
    global climate change. An increasing number of δ18O records in
    Brazil provide insight into late Holocene variation in the intensity of
    the South American Monsoon. δ18O values, although widely
    recognized as a proxy of regional climate, may not reflect local
    moisture conditions, making additional proxies necessary for
    reconstructing the impact of large-scale monsoon shifts on local
    hydrological cycles. We develop speleothem 87Sr/86Sr values as a local
    paleo-moisture proxy from Tamboril Cave in central Brazil to complement
    existing δ18O-based reconstructions of regional monsoon intensity.
    Analysis of leachates of soils and bedrock demonstrates that soils
    overlying the cave have distinctly higher 87Sr/86Sr values ( 0.732) than
    cave bedrock ( 0.712). Speleothem 87Sr/86Sr values (0.721-0.724) lie
    between soil and bedrock values suggesting that 87Sr/86Sr variations
    reflect varying extents of water-rock interaction. Greater extents of
    water-rock interaction results in evolution of water Sr isotope values
    away from those initially acquired from the soil and toward those of the
    bedrock. Increasing speleothem 87Sr/86Sr values over the past 1,500
    years are consistent with decreasing initial δ234U values, a
    complimentary proxy for water-rock interaction, over the same period.
    Both isotopic proxies suggest progressively less water-rock interaction
    through time. A reduction of water-rock interaction could reflect faster
    water transit from the surface to the cave due to changes in the amount
    or intensity of precipitation. Notably, development of speleothem Sr
    isotopes as a proxy of infiltration rates may, unlike trace elements and
    carbon isotopes, work in settings where the influence of prior calcite
    precipitation is minimal. Furthermore, δ18O records from the
    region do not document progressive changes in monsoon intensity over
    this interval, suggesting a possible decoupling between local moisture
    conditions and regional monsoon intensity in the late Holocene.
    Confirmation of such a decoupling would have important ecological and
    societal implications.
    BibTeX:
    @article{wortham_potential_2016,
      author = {Wortham, B. E. and Wong, C. I. and McGee, D. and Rasbury, T. and Silva, L. C. R. and Montanez, I. P. and Cooper, K. M. and Sharp, W. D. and Tappa, M. J.},
      title = {Potential decoupling between the regional monsoon intensity and local moisture conditions during the last millennium in central Brazil},
      journal = {AGU Fall Meeting Abstracts},
      year = {2016},
      volume = {24},
      url = {http://adsabs.harvard.edu/abs/2016AGUFMPP24A..02W}
    }
    					
    buelow_california_2015 Buelow, M.C.; Steenwerth, K.; Silva, L.C.R. & Parikh, S.J. A California Winery Wastewater Survey: Assessing the Salinity Challenge for Wastewater Reuse 2015 American Journal of Enology and Viticulture , pp. ajev.2015.14110   article bod, drought, greywater, potassium, reuse, salinity, sodium
    Abstract: Over thirty percent of the United States is currently considered to be in a drought that is expected to have profound social, economic, and environmental impacts. Drought conditions are intensifying in the southern and western regions of the country, spurring interest in wastewater reuse in agriculture, including wine production. Presented here is the first data set of its kind to support California growers and vintners reuse of treated winery wastewater (WWW). The data provide a detailed description of California WWW, with particular emphasis on WWW salinity, required to assess benefits and risks of land application. Monthly samples were obtained over a twenty month period from eighteen participating wineries in Ukiah, Napa, Lodi, King City, and Paso Robles. Samples collected prior to (pre-) and after (post-) treatment were analyzed for pH, electrical conductivity (EC), cation and anion concentrations, specific ultraviolet absorbance (SUVA254), dissolved organic carbon (DOC), and biological oxygen demand (BOD5). The pH of WWW varied widely (3–12). Organic parameters (SUVA254, DOC, and BOD5) indicated that treatment effectively decreased organic carbon to levels that would not have negative effects on plant growth and soil. Cation concentrations (Na+, K+, Ca2+, Mg2+) observed in this study were not reduced by WWW treatment, indicating salts stayed in solution after treatment. These baseline data confirm that dissolved salts pose one of the greatest challenges to reuse of WWW. However, measurements of total salinity (electrical conductivity) of the WWW at participating wineries was found to be moderate (mean of 1.0 dS/m), and usually below thresholds for common wine grape rootstocks and soil salinity hazards. The conditions under which WWW could be recommended as a water management option in California are described.
    BibTeX:
    @article{buelow_california_2015,
      author = {Buelow, Maya C. and Steenwerth, Kerri and Silva, Lucas C. R. and Parikh, Sanjai J.},
      title = {A California Winery Wastewater Survey: Assessing the Salinity Challenge for Wastewater Reuse},
      journal = {American Journal of Enology and Viticulture},
      year = {2015},
      pages = {ajev.2015.14110},
      url = {http://www.ajevonline.org/content/early/2015/06/12/ajev.2015.14110},
      doi = {http://doi.org/10.5344/ajev.2015.14110}
    }
    					
    de_oliveira_bomfim_quantifying_2015 De Oliveira Bomfim, B.; Silva, L.C.R.; Marimon-Junior, B.H.; Marimon, B.; Horwath, W.R. & Neves, L. Quantifying the effect of fire disturbance on free-living nitrogen fixation in tropical ecosystems 2015 AGU Fall Meeting Abstracts
    Vol. 13  
    inproceedings 0414 biogeochemical cycles, 0439 ecosystems, 1631 land/atmosphere interactions, 3305 climate change and variability, and modeling, atmospheric processes, biogeosciences, global change, processes, structure and dynamics
    Abstract: Tropical forests and savannas are among the most important biomes on
    Earth, supporting more than half of all plant and animal species on the
    planet. Despite growing interest in biogeochemical processes that affect
    tropical forest dynamics, many, including biological nitrogen fixation
    (BNF), are still poorly understood. Free-living N-fixers are thought to
    play a key role in tropical ecosystems, alleviating N and P limitation,
    supporting above and below ground biomass production, as well as carbon
    storage in plants and soil, but this influence has yet to be quantified.
    Of particular interest, the spatial distribution and identity of
    free-living BNF under disturbance regimes that commonly lead to the
    conversion of forests to savannas is currently unknown. To address this
    critical gap in knowledge, we measured free-living BNF quantifying rates
    of N fixation under contrasting fire regimes in the Amazon-Cerrado
    transition of central Brazil. Samples were collected in 4 ha of
    floodable forests affected by fire and 1 ha of unburned (seasonally
    flooded) forest located at the Araguaia State Park, Mato Grosso State,
    Brazil. Free-living N-fixation rates were measured by both 15N2 (98
    atom% 15N) and acethylene reduction assay (ARA). Samples were incubated
    in the field and left in the dark at room temperature for 12 hours. In
    the next few weeks we will quantify N fixation rates that will be
    presented in the upcoming AGU meeting.
    BibTeX:
    @article{de_oliveira_bomfim_quantifying_2015,
      author = {De Oliveira Bomfim, B. and Silva, L. C. R. and Marimon-Junior, B. H. and Marimon, B. and Horwath, W. R. and Neves, L.},
      title = {Quantifying the effect of fire disturbance on free-living nitrogen fixation in tropical ecosystems},
      journal = {AGU Fall Meeting Abstracts},
      year = {2015},
      volume = {13},
      url = {http://adsabs.harvard.edu/abs/2015AGUFM.B13F0694D}
    }
    					
    jerszurki_impact_2015 Jerszurki, D.; Couvreur, V.; Hopmans, J.W.; Silva, L.C.R.; Shackel, K.A. & de Souza, J.L.M. Impact of root growth and root hydraulic conductance on water availability of young walnut trees 2015
    Vol. 17 , pp. 596  
    inproceedings
    Abstract: Walnut (Juglans regia L.) is a tree species of high economic importance
    in the Central Valley of California. This crop has particularly high
    water requirements, which makes it highly dependent on irrigation. The
    context of decreasing water availability in the state calls for
    efficient water management practices, which requires improving our
    understanding of the relationship between water application and walnut
    water availability. In addition to the soil's hydraulic conductivity,
    two plant properties are thought to control the supply of water from the
    bulk soil to the canopy: (i) root distribution and (ii) plant hydraulic
    conductance. Even though these properties are clearly linked to crop
    water requirements, their quantitative relation remains unclear. The aim
    of this study is to quantitatively explain walnut water requirements
    under water deficit from continuous measurements of its water
    consumption, soil and stem water potential, root growth and root system
    hydraulic conductance. For that purpose, a greenhouse experiment was
    conducted for a two month period. Young walnut trees were planted in
    transparent cylindrical pots, equipped with: (i) rhizotron tubes, which
    allowed for non-invasive monitoring of root growth, (ii) pressure
    transducer tensiometers for soil water potential, (iii) psychrometers
    attached to non-transpiring leaves for stem water potential, and (iv)
    weighing scales for plant transpiration. Treatments consisted of
    different irrigation rates: 100 75% and 50% of potential crop
    evapotranspiration. Plant responses were compared to predictions from
    three simple process-based soil-plant-atmosphere models of water flow:
    (i) a hydraulic model of stomatal regulation based on stem water
    potential and vapor pressure deficit, (ii) a model of plant hydraulics
    predicting stem water potential from soil-root interfaces water
    potential, and (iii) a model of soil water depletion predicting the
    water potential drop between the bulk soil and soil-root interfaces.
    These models were combined to a global optimization algorithm to obtain
    parameters that best fit the observed soil-plant-atmosphere water
    dynamics. Eventually, relations between root system conductance and
    growth as well as water access strategies were quantitatively analyzed.
    BibTeX:
    @inproceedings{jerszurki_impact_2015,
      author = {Jerszurki, Daniela and Couvreur, Valentin and Hopmans, Jan W. and Silva, Lucas C. R. and Shackel, Kenneth A. and de Souza, Jorge L. M.},
      title = {Impact of root growth and root hydraulic conductance on water availability of young walnut trees},
      year = {2015},
      volume = {17},
      pages = {596},
      url = {http://adsabs.harvard.edu/abs/2015EGUGA..17..596J}
    }
    					
    maxwell_soil_2015 Maxwell, T.; Silva, L.C.R. & Horwath, W.R. Soil Properties Drive Changes in Water Use efficiency Across a Climatic Gradient 2015 AGU Fall Meeting Abstracts
    Vol. 53  
    inproceedings 0414 biogeochemical cycles, 0428 carbon cycling, 0486 soils/pedology, 1813 eco-hydrology, and modeling, biogeosciences, hydrology, processes
    Abstract: This research uses a series of physiological models and empirical
    measurements to evaluate biogeochemical controls over coupled
    carbon-water cycles in forest systems from the individual plant to the
    ecosystem scale. Cellulosic biomarkers, and bulk tissue of leaf, litter,
    and soil organic matter have been analyzed for specific stable isotope
    ratios of oxygen and carbon to examine causal links between plant to
    ecosystem scale productivity and water balance. A series of latitudinal
    and altitudinal transects established across the California Sierra
    Nevada was used to study the effects of climatic and edaphic gradients
    on the formation and preservation of these plant isotopic signals.
    Changes in plant-soil-atmosphere relations are related to productivity
    and water use efficiency in an attempt to elucidate how plant material
    reflects ecosystem scale processes in response to variation in climate
    and soil properties. The use of a dual isotopic approach constrains the
    role of environmental variables on stable isotope values, allowing for
    nutritive vs hydrologic limitations over water use efficiency to be
    assessed. The result of this work is to promote a framework for tracing
    plant-soil water relations across scales to better understand and more
    precisely predict the impacts of climate change on forest ecosystems.
    BibTeX:
    @article{maxwell_soil_2015,
      author = {Maxwell, T. and Silva, L. C. R. and Horwath, W. R.},
      title = {Soil Properties Drive Changes in Water Use efficiency Across a Climatic Gradient},
      journal = {AGU Fall Meeting Abstracts},
      year = {2015},
      volume = {53},
      url = {http://adsabs.harvard.edu/abs/2015AGUFM.B53G0641M}
    }
    					
    paiva_productivity-efficiency_2015 Paiva, A.O.; Silva, L.C.R. & Haridasan, M. Productivity-efficiency tradeoffs in tropical gallery forest-savanna transitions: linking plant and soil processes through litter input and composition 2015 Plant Ecology
    Vol. 216 (6) , pp. 775-787  
    article
    Abstract: Vegetation gradients in Central Brazil encompass sharp transitions from savanna to forests, representing an iconic example of how interactions between plants and soils regulate biogeographical boundaries. Here we describe how canopy productivity regulates nutrient inputs to soils, affecting fertility and influencing ecosystem distribution. Based on soil and litter systematically collected during 12 months along a gallery forest-savanna transition, we determined associations between canopy cover (leaf area index—LAI) and the (re)cycling of essential macronutrients. This evaluation was aimed at aggregating information about biogeochemical controls of ecosystem distribution/productivity, to support conservation and management efforts in the region. We confirmed two hypotheses: (i) nutrient inputs via litterfall are significantly higher in forest than in adjacent savanna, and (ii) litter quality varies with canopy productivity and litter nutrient concentrations influence soil fertility reinforcing forest and savanna as alternate stable states. These observations delineate a productivity-efficiency tradeoff in which savannas communities are more efficient in the use of limiting nutrients, yet, less productive than forest communities. The relative importance of different nutrients, apparent on recovery rates in the litter regressed against LAI, revealed that the expansion of forest ecosystems is limited by P textgreater Mg textgreater K textgreater N, with highest conservation observed for P. Differences in Ca input were also significant among ecosystems, but depended solely on the amount of deposited litter, with no differences in recovery rates observed between forests and savannas. A tradeoff-based framework could be used to predict ecotonal stability in the region, with transitions between savannas and forests marked by clear changes in species composition, productivity, litter deposition, and soil fertility.
    BibTeX:
    @article{paiva_productivity-efficiency_2015,
      author = {Paiva, Artur Orelli and Silva, Lucas Carvalho Ramos and Haridasan, Mundayatan},
      title = {Productivity-efficiency tradeoffs in tropical gallery forest-savanna transitions: linking plant and soil processes through litter input and composition},
      journal = {Plant Ecology},
      year = {2015},
      volume = {216},
      number = {6},
      pages = {775--787},
      url = {https://link.springer.com/article/10.1007/s11258-015-0466-8},
      doi = {http://doi.org/10.1007/s11258-015-0466-8}
    }
    					
    shi_climate_2015 Shi, C.; Silva, L.C.R.; Zhang, H.; Zheng, Q.; Xiao, B.; Wu, N. & Sun, G. Climate warming alters nitrogen dynamics and total non-structural carbohydrate accumulations of perennial herbs of distinctive functional groups during the plant senescence in autumn in an alpine meadow of the Tibetan Plateau, China 2015 Agricultural and Forest Meteorology
    Vol. 200 (Supplement C) , pp. 21-29  
    article autumn, carbohydrate reserves, chlorophyll degradation, climate warming, functional group, perennial herbs
    Abstract: Although photoperiod is known to be the main factor driving plant senescence in perennial plants, temperature has also been shown to modulate this process, which suggests that climate warming will significantly impact the length of plant growing season and affect terrestrial productivity. To test this assumption, we measured the effects of simulated autumn warming on four perennial herbaceous species, i.e. Elymus nutans, Koeleria macrantha, Vicia unijuga and Allium atrosanguineum, representing two major plant functional groups (grasses and forbs), in a typical alpine meadow of the Tibetan Plateau. Warming was simulated using open-top chambers, and its effects on degradation of chlorophyll and nitrogen (N) concentration in leaves and stems were determined during the senescence processes in autumn. The potential effects of autumn warming on total non-structural carbohydrate (TNC) in roots, growth and flowering phenology were further investigated in the following year. We found that warming delayed chlorophyll degradation of perennial herbs in early phase but accelerated it in later phase, regardless of functional groups, which led to higher N concentrations in leaves and stems during the whole senescence period. Autumn warming also significantly increased TNC in roots as a result of the delayed process of chlorophyll degradation, although the magnitudes were dependent on functional groups, which may be explained by inherent differences in growth patterns and phenology between grasses and forbs. We demonstrate that warming can increase carbohydrate accumulation not only by enhancing activities of photosynthetic enzymes proved by many previous studies but by altering chlorophyll degradation and preferential allocation of resources to different compartments. Furthermore, these results suggest that the net effect of climate warming on terrestrial ecosystems will be determined by floristic composition, as contrasting immediate and lasting (one year) changes in nutrient use and carbon allocation in response to warming were observed among species.
    BibTeX:
    @article{shi_climate_2015,
      author = {Shi, Changguang and Silva, Lucas C. R. and Zhang, Hongxuan and Zheng, Qunying and Xiao, Bingxue and Wu, Ning and Sun, Geng},
      title = {Climate warming alters nitrogen dynamics and total non-structural carbohydrate accumulations of perennial herbs of distinctive functional groups during the plant senescence in autumn in an alpine meadow of the Tibetan Plateau, China},
      journal = {Agricultural and Forest Meteorology},
      year = {2015},
      volume = {200},
      number = {Supplement C},
      pages = {21--29},
      url = {http://www.sciencedirect.com/science/article/pii/S0168192314002172},
      doi = {http://doi.org/10.1016/j.agrformet.2014.09.006}
    }
    					
    silva_air_2015 Silva, L.C.R. From air to land: understanding water resources through plant-based multidisciplinary research 2015 Trends in Plant Science
    Vol. 20 (7) , pp. 399-401  
    article climatic change, drought, human–environment systems, socioecology, soil–plant–atmosphere interactions, stable isotopes, water-use efficiency
    Abstract: Current global challenges require solutions that cannot be delivered by any one field alone. New developments in the analysis and interpretation of plant-derived climatic records bridge traditional disciplines, advancing understanding of phenomena of great ecological and societal significance, specifically, those related to changes in the terrestrial water cycle.
    BibTeX:
    @article{silva_air_2015,
      author = {Silva, Lucas C. R.},
      title = {From air to land: understanding water resources through plant-based multidisciplinary research},
      journal = {Trends in Plant Science},
      year = {2015},
      volume = {20},
      number = {7},
      pages = {399--401},
      url = {http://www.sciencedirect.com/science/article/pii/S1360138515001363},
      doi = {http://doi.org/10.1016/j.tplants.2015.05.007}
    }
    					
    silva_beyond_2015 Silva, L.C.R.; Pedroso, G.; Doane, T.A.; Mukome, F.N.D. & Horwath, W.R. Beyond the cellulose: Oxygen isotope composition of plant lipids as a proxy for terrestrial water balance 2015 Geochemical Perspectives Letters , pp. 33-42   article
    BibTeX:
    @article{silva_beyond_2015,
      author = {Silva, L.C.R. and Pedroso, G. and Doane, T.A. and Mukome, F.N.D. and Horwath, W.R.},
      title = {Beyond the cellulose: Oxygen isotope composition of plant lipids as a proxy for terrestrial water balance},
      journal = {Geochemical Perspectives Letters},
      year = {2015},
      pages = {33--42},
      url = {http://www.geochemicalperspectivesletters.org/article1504},
      doi = {http://doi.org/10.7185/geochemlet.1504}
    }
    					
    silva_carbon_2015 Silva, L.C.R.; Salamanca-Jimenez, A.; Doane, T.A. & Horwath, W.R. Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees 2015 Scientific Reports
    Vol. 5  
    article
    Abstract: The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases (13CO2 and 15NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the 13CO2 pulse, assimilation and transport of the 15NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.
    BibTeX:
    @article{silva_carbon_2015,
      author = {Silva, Lucas C. R. and Salamanca-Jimenez, Alveiro and Doane, Timothy A. and Horwath, William R.},
      title = {Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees},
      journal = {Scientific Reports},
      year = {2015},
      volume = {5},
      url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4543970/},
      doi = {http://doi.org/10.1038/srep13141}
    }
    					
    silva_iron-mediated_2015 Silva, L.C.R.; Doane, T.A.; Corrźa, R.S.; Valverde, V.; Pereira, E.I.P. & Horwath, W.R. Iron-mediated stabilization of soil carbon amplifies the benefits of ecological restoration in degraded lands 2015 Ecological Applications
    Vol. 25 (5) , pp. 1226-1234  
    article carbon sequestration, iron, land restoration, soil–plant interactions, stable isotopes, urban waste
    Abstract: Recent observations across a 14-year restoration chronosequence have shown an unexpected accumulation of soil organic carbon in strip-mined areas of central Brazil. This was attributed to the rapid plant colonization that followed the incorporation of biosolids into exposed regoliths, but the specific mechanisms involved in the stabilization of carbon inputs from the vegetation remained unclear. Using isotopic and elemental analyses, we tested the hypothesis that plant-derived carbon accumulation was triggered by the formation of iron-coordinated complexes, stabilized into physically protected (occluded) soil fractions. Confirming this hypothesis, we identified a fast formation of microaggregates shortly after the application of iron-rich biosolids, which was characterized by a strong association between pyrophosphate-extractable iron and plant-derived organic matter. The formation of microaggregates preceded the development of macroaggregates, which drastically increased soil carbon content (˜140 Mg C/ha) a few years after restoration. Consistent with previous theoretical work, iron-coordinated organic complexes served as nuclei for aggregate formation, reflecting the synergistic effect of biological, chemical, and physical mechanisms of carbon stabilization in developing soils. Nevertheless, iron was not the only factor affecting soil carbon content. The highest carbon accumulation was observed during the period of highest plant diversity (textgreater30 species; years 3–6), declining significantly with the exclusion of native species by invasive grasses (years 9–14). Furthermore, the increasing dominance of invasive grasses was associated with a steady decline in the concentration of soil nitrogen and phosphorus per unit of accumulated carbon. These results demonstrate the importance of interdependent ecological and biogeochemical processes, and the role of soil–plant interactions in determining the success of restoration efforts. In contrast with previous but unsuccessful attempts to restore mined areas through nutrient application alone, iron-mediated stabilization of vegetation inputs favored the regeneration of a barren stable state that had persisted for over five decades since disturbance. The effectiveness of coupled organic matter and iron “fertilization,” combined with management of invasive species, has the possibility to enhance terrestrial carbon sequestration and accelerate the restoration of degraded lands, while addressing important challenges associated with urban waste disposal.
    BibTeX:
    @article{silva_iron-mediated_2015,
      author = {Silva, Lucas C. R. and Doane, Timothy A. and Corrźa, Rodrigo S. and Valverde, Vinicius and Pereira, Engil I. P. and Horwath, William R.},
      title = {Iron-mediated stabilization of soil carbon amplifies the benefits of ecological restoration in degraded lands},
      journal = {Ecological Applications},
      year = {2015},
      volume = {25},
      number = {5},
      pages = {1226--1234},
      url = {http://onlinelibrary.wiley.com/doi/10.1890/14-2151.1/abstract},
      doi = {http://doi.org/10.1890/14-2151.1}
    }
    					
    silva_isotopic_2015 Silva, L.C.R.; Gómez-Guerrero, A.; Doane, T.A. & Horwath, W.R. Isotopic and nutritional evidence for species- and site-specific responses to N deposition and elevated CO2 in temperate forests 2015 Journal of Geophysical Research: Biogeosciences
    Vol. 120 (6) , pp. 2014JG002865  
    article 0426 biosphere/atmosphere interactions, 0428 carbon cycling, 0454 isotopic composition and chemistry, 0469 nitrogen cycling, 0470 nutrients and nutrient cycling, atmospheric pollution, c and n isotopes, forest decline, n deposition, soil-plant-atmosphere interactions
    Abstract: In this study we show that the effect of rising atmospheric CO2 levels on forest productivity is influenced by changes in nutrient availability caused by nitrogen (N) deposition. We used a dual-isotope approach (δ15N and δ13C), combined with dendrochronological and nutritional analyses, to evaluate the response of two dominant tree species in natural forest ecosystems near Mexico City (Pinus hartwegii—pine; Abies religiosa—fir). Our analysis focuses on changes that occurred over the past 50 years at two sites, one under high and one under low N deposition rates. Analyses of carbon isotope composition indicate increasing water-use efficiency in response to rising CO2 levels for both species and sites but this effect did not lead to improved tree growth. The magnitude and direction of shifts in 13C discrimination indicate a process of acclimation that varied with the rate of N deposition and species traits. Since the 1960s, strong negative responses to N deposition have been observed in fir trees, which showed altered foliar nutrition and growth decline, while the negative impacts of N deposition on pine trees remained undetectable until the 1990s. In recent years, both species have shown significant growth decline under high N deposition despite increasing atmospheric CO2. Multivariate analysis of leaf nutrients indicates that growth decline was prompted by depleted soil macronutrient (P, K, and Ca) and micronutrient (Cu, Fe, Zn, and Mn) availability. At both sites, fir trees were a better indicator of N deposition due to differences in canopy rainfall interception.
    BibTeX:
    @article{silva_isotopic_2015,
      author = {Silva, Lucas C. R. and Gómez-Guerrero, Armando and Doane, Timothy A. and Horwath, William R.},
      title = {Isotopic and nutritional evidence for species- and site-specific responses to N deposition and elevated CO2 in temperate forests},
      journal = {Journal of Geophysical Research: Biogeosciences},
      year = {2015},
      volume = {120},
      number = {6},
      pages = {2014JG002865},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/2014JG002865/abstract},
      doi = {http://doi.org/10.1002/2014JG002865}
    }
    					
    silva_seasonal_2015 Silva, L. Seasonal variation in groundwater depth does not explain structure and diversity of tropical savannas 2015 Journal of Vegetation Science
    Vol. 26 (2) , pp. 404-406  
    article cerrado, ecotones, nutrient limitation, soil-plant interactions, vegetation dynamics
    Abstract: It has recently been proposed that seasonal fluctuations in groundwater depth drive spatial patterns of tree density and diversity in Neotropical savannas. Here I consider three major problems in the analysis that led to this conclusion, providing examples that demonstrate that groundwater levels do not constrain the establishment of woody communities and, therefore, cannot be used to explain patterns of tree density and diversity in savannas.
    BibTeX:
    @article{silva_seasonal_2015,
      author = {Silva, L.c.r.},
      title = {Seasonal variation in groundwater depth does not explain structure and diversity of tropical savannas},
      journal = {Journal of Vegetation Science},
      year = {2015},
      volume = {26},
      number = {2},
      pages = {404--406},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/jvs.12244/abstract},
      doi = {http://doi.org/10.1111/jvs.12244}
    }
    					
    wang_quantifying_2015 Wang, Z.; Silva, L.C.R.; Sun, G.; Luo, P.; Mou, C. & Horwath, W.R. Quantifying the impact of drought on soil-plant interactions: a seasonal analysis of biotic and abiotic controls of carbon and nutrient dynamics in high-altitudinal grasslands 2015 Plant and Soil
    Vol. 389 (1-2) , pp. 59-71  
    article
    Abstract: Background and aimsUnderstanding the impacts of ever more severe and widespread drought events has become a central focus of recent ecological research. Accordingly, the objective of this study is to investigate fundamental mechanisms that control drought effects on climate sensitive ecosystems by regulating soil-plant interactions.MethodsField experiments were conducted in high altitudinal grasslands of the Tibetan Plateau. Based on historical records, we simulated extreme drought events, intercepting water inputs in early (spring), mid (summer), and late (autumn) periods of the plant-growing season (PGS). We measured vegetation responses to changes in soil physical, chemical, and biological properties, examining how the interplay of abiotic and biotic processes regulate the impacts of drought above and below ground.ResultsDecreasing water input resulted in proportional increases in summer and autumn soil temperature, but reduced soil temperature during the spring drought. As a result, soil microbial biomass and available N and P concentrations remained stable during the early-PGS drought, while enzymatic activity, decomposition of organic materials, and nutrient release increased during the mid- and late-PGS. Concerted changes in microbial and plant activity determined seasonal fluctuations in carbon assimilation, microbial activity and nutrient dynamics, with varying degrees of resistance and resilience to drought stress observed at different PGS periods.ConclusionsSignificant interactions were observed between plant productivity and microbial activity in response to moisture variability and associated changes in soil temperature, with the largest deleterious drought effects registered during the summer, when competition for limiting resources between plants and microorganisms was strongest.
    BibTeX:
    @article{wang_quantifying_2015,
      author = {Wang, Zhiyuan and Silva, Lucas C. R. and Sun, Geng and Luo, Peng and Mou, Chengxiang and Horwath, William R.},
      title = {Quantifying the impact of drought on soil-plant interactions: a seasonal analysis of biotic and abiotic controls of carbon and nutrient dynamics in high-altitudinal grasslands},
      journal = {Plant and Soil},
      year = {2015},
      volume = {389},
      number = {1-2},
      pages = {59--71},
      url = {https://link.springer.com/article/10.1007/s11104-014-2337-9},
      doi = {http://doi.org/10.1007/s11104-014-2337-9}
    }
    					
    wortham_comparison_2015 Wortham, B.E.; Wong, C.I.; Montanez, I.P.; Silva, L.C.R.; Rasbury, T. & Glessner, J.J. Comparison of laser-ablation and solution-mode ICP-MS techniques for measuring speleothem 87Sr/86Sr values 2015 AGU Fall Meeting Abstracts
    Vol. 53  
    inproceedings 0419 biomineralization, 0473 paleoclimatology and paleoceanography, 4912 biogeochemical cycles, 4924 geochemical tracers, and modeling, biogeosciences, paleoceanography, processes
    Abstract: Reconstructing past changes in precipitation amount is critical to
    delineating controls on paleovegetation dynamics in South America.
    Although speleothem, lake, and ice core δ18O records from the
    region serve as a proxy of monsoon intensity, δ18O values do not
    serve as a direct proxy of local precipitation amount. To address this,
    we are developing a reconstruction of past moisture conditions using
    87Sr/86Sr values measured in a fast growing speleothem (˜2 mm/yr) from
    the central Brazilian savanna for which a late Holocene (0-1.8 ka)
    δ18O record has previously been developed. Speleothem 87Sr/86Sr
    values reflect the degree of water-rock interaction, as dictated by
    water residence time, and are used to interpret relative moisture
    conditions. In this study, we explore the potential of developing a
    high-resolution speleothem 87Sr/86Sr record using laser-ablation
    multi-collector ICP-MS by comparing analyses generated using both laser-
    and solution-mode techniques. Laser-mode techniques allow for sampling
    of individual speleothem lamina, which provides a higher resolution
    record than solution-mode techniques and eliminates the potential of
    contamination from conventional drilling. Preliminary results from a
    younger portion of the speleothem yield a laser-mode (averaged) value of
    0.72294 Ī 0.00046 (reproduced with parallel scans) and a solution
    mode value of 0.72338 Ī 0.00002 suggesting that these methods
    provide analogous 87Sr/86Sr values. However, the preliminary results on
    an older portion of this speleothem have solution- mode derived values
    of 0.72239 Ī 0.00001 and 0.72166 Ī 0.00001, with
    corresponding laser-mode values of 0.72188 Ī 0.00029 and 0.72102
    Ī 0.00037, respectively. Suggesting that in the older portion of
    the speleothem, laser-mode techniques do not yield analogous
    solution-mode 87Sr/86Sr values. These differences in different areas of
    the speleothem highlight the need for method development and further
    testing.
    BibTeX:
    @article{wortham_comparison_2015,
      author = {Wortham, B. E. and Wong, C. I. and Montanez, I. P. and Silva, L. C. R. and Rasbury, T. and Glessner, J. J.},
      title = {Comparison of laser-ablation and solution-mode ICP-MS techniques for measuring speleothem 87Sr/86Sr values},
      journal = {AGU Fall Meeting Abstracts},
      year = {2015},
      volume = {53},
      url = {http://adsabs.harvard.edu/abs/2015AGUFMPP53B2351W}
    }
    					
    franco_cerrado_2014 Franco, A.C.; Rossatto, D.R.; Silva, L. d.C.R. & Ferreira, C. d.S. Cerrado vegetation and global change: the role of functional types, resource availability and disturbance in regulating plant community responses to rising CO2 levels and climate warming 2014 Theoretical and Experimental Plant Physiology
    Vol. 26 (1) , pp. 19-38  
    article
    Abstract: The cerrado is the most extensive savanna ecosystem of South America and a biodiversity hotspot, harboring a diverse flora (textgreater7,000 species) with high levels of endemism. More than 50 % of the cerrado’s approximately 2 million km2 has been converted into pasture and agricultural lands and it is uncertain how the remaining areas will respond to increasing pressures from land use and climate change. Interactions between disturbance regime and resource (water and nutrient) availability are known to determine the distribution of the various plant communities, of contrasting structure and composition, which coexist in the region. We discuss how fire, nutrients and species traits regulate plant community responses to rising CO2 and global warming, exploring constraints to forest expansion into savanna environments. We describe how climate change will likely reverse a natural process of forest expansion, observed in the region over the past few millennia, accelerating tree cover loss through feedbacks involving fire and resource limitation, and counteracting expected CO2 stimulation effects. These involve changes in fundamental processes occurring above and below ground, which will probably also impact species performance, distribution and biodiversity patterns. We propose a conceptual framework for predicting changes on vegetation structure, highlighting the need for mechanistic models to accurately simulate vegetation dynamics under climate change scenarios. We conclude by explaining why an effective research agenda must necessarily include mitigation efforts, aimed at minimizing impacts of land clearing through enforced conservation and restoration policies in natural and managed ecosystems.
    BibTeX:
    @article{franco_cerrado_2014,
      author = {Franco, Augusto Cesar and Rossatto, Davi Rodrigo and Silva, Lucas de Carvalho Ramos and Ferreira, Cristiane da Silva},
      title = {Cerrado vegetation and global change: the role of functional types, resource availability and disturbance in regulating plant community responses to rising CO2 levels and climate warming},
      journal = {Theoretical and Experimental Plant Physiology},
      year = {2014},
      volume = {26},
      number = {1},
      pages = {19--38},
      url = {https://link.springer.com/article/10.1007/s40626-014-0002-6},
      doi = {http://doi.org/10.1007/s40626-014-0002-6}
    }
    					
    ladd_carbon_2014 Ladd, B.; Peri, P.L.; Pepper, D.A.; Silva, L.C.R.; Sheil, D.; Bonser, S.P.; Laffan, S.W.; Amelung, W.; Ekblad, A.; Eliasson, P.; Bahamonde, H.; Duarte-Guardia, S. & Bird, M. Carbon isotopic signatures of soil organic matter correlate with leaf area index across woody biomes 2014 Journal of Ecology
    Vol. 102 (6) , pp. 1606-1611  
    article climate, isoscapes, leaf area index, paleoecosystems, plant–soil (below-ground) interactions, productivity, stable isotopes, water stress, δ13c, δ13csom
    Abstract: * Leaf area index (LAI), a measure of canopy density, is a key variable for modelling and understanding primary productivity, and also water use and energy exchange in forest ecosystems. However, LAI varies considerably with phenology and disturbance patterns, so alternative approaches to quantifying stand-level processes should be considered. The carbon isotope composition of soil organic matter (δ13CSOM) provides a time-integrated, productivity-weighted measure of physiological and stand-level processes, reflecting biomass deposition from seasonal to decadal time scales.

    * Our primary aim was to explore how well LAI correlates with δ13CSOM across biomes.

    * Using a global data set spanning large environmental gradients in tropical, temperate and boreal forest and woodland, we assess the strength of the correlation between LAI and δ13CSOM; we also assess climatic variables derived from the WorldClim database.

    * We found that LAI was strongly correlated with δ13CSOM, but was also correlated with Mean Temperature of the Wettest Quarter, Mean Precipitation of Warmest Quarter and Annual Solar Radiation across and within biomes.

    * Synthesis. Our results demonstrate that δ13CSOM values can provide spatially explicit estimates of leaf area index (LAI) and could therefore serve as a surrogate for productivity and water use. While δ13CSOM has traditionally been used to reconstruct the relative abundance of C3 versus C4 species, the results of this study demonstrate that within stable C3- or C4-dominated biomes, δ13CSOM can provide additional insights. The fact that LAI is strongly correlated to δ13CSOM may allow for a more nuanced interpretation of ecosystem properties of palaeoecosystems based on palaeosol 13C values.

    BibTeX:
    @article{ladd_carbon_2014,
      author = {Ladd, Brenton and Peri, Pablo L. and Pepper, David A. and Silva, Lucas C. R. and Sheil, Douglas and Bonser, Stephen P. and Laffan, Shawn W. and Amelung, Wulf and Ekblad, Alf and Eliasson, Peter and Bahamonde, Hector and Duarte-Guardia, Sandra and Bird, Michael},
      title = {Carbon isotopic signatures of soil organic matter correlate with leaf area index across woody biomes},
      journal = {Journal of Ecology},
      year = {2014},
      volume = {102},
      number = {6},
      pages = {1606--1611},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12309/abstract},
      doi = {http://doi.org/10.1111/1365-2745.12309}
    }
    					
    maxwell_using_2014 Maxwell, T.M.; Silva, L.C.R. & Horwath, W.R. Using multielement isotopic analysis to decipher drought impacts and adaptive management in ancient agricultural systems 2014 Proceedings of the National Academy of Sciences
    Vol. 111 (45) , pp. E4807-E4808  
    article
    Abstract: National Academy of Sciences
    BibTeX:
    @article{maxwell_using_2014,
      author = {Maxwell, Toby M. and Silva, Lucas C. R. and Horwath, William R.},
      title = {Using multielement isotopic analysis to decipher drought impacts and adaptive management in ancient agricultural systems},
      journal = {Proceedings of the National Academy of Sciences},
      year = {2014},
      volume = {111},
      number = {45},
      pages = {E4807--E4808},
      url = {http://www.pnas.org/content/111/45/E4807},
      doi = {http://doi.org/10.1073/pnas.1417618111}
    }
    					
    qiao_understory_2014 Qiao, Y.; Miao, S.; Silva, L.C.R. & Horwath, W.R. Understory species regulate litter decomposition and accumulation of C and N in forest soils: A long-term dual-isotope experiment 2014 Forest Ecology and Management
    Vol. 329 (Supplement C) , pp. 318-327  
    article c, n, nutrient cycling, soil–plant interactions, stable isotopes
    Abstract: We investigated the effect of understory vegetation on soil C and N dynamics in two Pinus ponderosa plantations under contrasting edaphic and climatic conditions, where understory is often removed to reduce fire risk and competition for water and nutrients. A dual-isotope (13C and 15N) experiment was used to trace C and N from various litter mixtures (i.e., pine and understory litter, as well as their mixture, with and without isotope label replicated in a completely randomized design at each site) and into multiple soil depths and physical fractions following 10years of decomposition. The presence of understory shrubs increased decomposition and accumulation of C and N from P. ponderosa litter in forest soils. Patterns of C and N accumulation varied with both treatment (litter composition) and environmental conditions (site), but the general response was similar in both plantations. Understory removal favored accumulation of undecomposed residues (light fraction), while addition of understory litter induced aggregate formation and accumulation of litter-derived C and N in occluded and mineral fractions. After 10years of decomposition, most of litter biomass was lost (70–89 and litter-derived C and N represented less than 1% of the original soil pool, but the presence of understory vegetation increased accumulation of litter C and N into occluded soil fractions. Despite large C and N losses the presence of understory vegetation increased the long-term productivity of forest soils, enhancing turnover, stabilizing organic matter and conserving N.
    BibTeX:
    @article{qiao_understory_2014,
      author = {Qiao, Yunfa and Miao, Shujie and Silva, Lucas C. R. and Horwath, William R.},
      title = {Understory species regulate litter decomposition and accumulation of C and N in forest soils: A long-term dual-isotope experiment},
      journal = {Forest Ecology and Management},
      year = {2014},
      volume = {329},
      number = {Supplement C},
      pages = {318--327},
      url = {http://www.sciencedirect.com/science/article/pii/S0378112714002643},
      doi = {http://doi.org/10.1016/j.foreco.2014.04.025}
    }
    					
    rossatto_woody_2014 Rossatto, D.R.; Silva, L.C.R.; Sternberg, L.S.L. & Franco, A.C. Do woody and herbaceous species compete for soil water across topographic gradients? Evidence for niche partitioning in a Neotropical savanna 2014 South African Journal of Botany
    Vol. 91 (Supplement C) , pp. 14-18  
    article cerrado, growth forms, herbaceous layer, niche partitioning, resource use, water uptake, woody layer
    Abstract: Savannas are characterized by sparsely distributed woody species within a continuous herbaceous cover, composed mainly by grasses and small eudicot herbs. This vegetation structure is variable across the landscape, with shifts from open grassland to savanna woodland determined by factors that control tree density. These shifts often appear coupled with environmental variations, such as topographic gradients. Here we investigated whether herbaceous and woody savanna species differ in their use of soil water along a topographic gradient of about 110m, spanning several vegetation physiognomies generally associated with Neotropical savannas. We measured the δ2H and δ18O signatures of plants, soils, groundwater and rainfall, determining the depth of plant water uptake and examining variations in water uptake patterns along the gradient. We found that woody species use water from deeper soil layers compared to herbaceous species, regardless of their position in the topographic gradient. However, the presence of a shallow water table restricted plant water uptake to the superficial soil layers at lower portions of the gradient. We confirmed that woody and herbaceous species are plastic with respect to their water use strategy, which determines niche partitioning across topographic gradients. Abiotic factors such as groundwater level, affect water uptake patterns independently of plant growth form, reinforcing vegetation gradients by exerting divergent selective pressures across topographic gradients.
    BibTeX:
    @article{rossatto_woody_2014,
      author = {Rossatto, D. R. and Silva, L. C. R. and Sternberg, L. S. L. and Franco, A. C.},
      title = {Do woody and herbaceous species compete for soil water across topographic gradients? Evidence for niche partitioning in a Neotropical savanna},
      journal = {South African Journal of Botany},
      year = {2014},
      volume = {91},
      number = {Supplement C},
      pages = {14--18},
      url = {http://www.sciencedirect.com/science/article/pii/S025462991300464X},
      doi = {http://doi.org/10.1016/j.sajb.2013.11.011}
    }
    					
    silva_importance_2014 Silva, L.C.R. Importance of climate-driven forest–savanna biome shifts in anthropological and ecological research 2014 Proceedings of the National Academy of Sciences
    Vol. 111 (37) , pp. E3831-E3832  
    article
    Abstract: National Academy of Sciences
    BibTeX:
    @article{silva_importance_2014,
      author = {Silva, Lucas C. R.},
      title = {Importance of climate-driven forest–savanna biome shifts in anthropological and ecological research},
      journal = {Proceedings of the National Academy of Sciences},
      year = {2014},
      volume = {111},
      number = {37},
      pages = {E3831--E3832},
      url = {http://www.pnas.org/content/111/37/E3831},
      doi = {http://doi.org/10.1073/pnas.1413205111}
    }
    					
    silva_natural_2014 Silva, L.C.R. Natural history and evolution of the Kwongan – a global biodiversity hotspot 2014 Trends in Plant Science
    Vol. 19 (11) , pp. 686  
    article
    BibTeX:
    @article{silva_natural_2014,
      author = {Silva, Lucas C. R.},
      title = {Natural history and evolution of the Kwongan – a global biodiversity hotspot},
      journal = {Trends in Plant Science},
      year = {2014},
      volume = {19},
      number = {11},
      pages = {686},
      url = {http://www.cell.com/trends/plant-science/abstract/S1360-1385(14)00204-0},
      doi = {http://doi.org/10.1016/j.tplants.2014.08.002}
    }
    					
    anand_scientific_2013 Anand, M.; Leithead, M.; Silva, L.C.R.; Wagner, C.; Ashiq, M.W.; Cecile, J.; Drobyshev, I.; Bergeron, Y.; Das, A. & Bulger, C. The scientific value of the largest remaining old-growth red pine forests in North America 2013 Biodiversity and Conservation
    Vol. 22 (8) , pp. 1847-1861  
    article
    Abstract: Old growth red pine forests (Pinus resinosa) cover less than 1% of their original range in North America and are essential for maintaining biodiversity at stand and landscape scales. Despite this, the largest remaining old-growth red pine forest in the world, the Wolf Lake Forest Reserve, is currently threatened by mining claims in Northern Ontario and has been receiving considerable media and public attention in recent months. We provide a timely review of how large old growth red pine forests maintain biodiversity at several taxonomic levels (with a focus on trees and plants) through heterogeneous partitioning of limiting resources such as light and nitrogen, formation of complex habitats through increased accumulation of coarse woody debris, and the maintenance of natural disturbance-driven succession. These processes shape the overstory community, allowing for the regeneration of pines, coexistence of early-mid successional shade intolerant species and cross-ecotonal establishment of late successional tree species in response to regional warming over the past three decades. Using Wolf Lake as a case study, we review legislation and policy complexities around this issue and provide scientific arguments for the preservation of this forest. We invoke recent insights into the ecological role of refugia, the development of criteria for assessing endangered ecosystems, and the challenges of conservation in the face of climate change and disturbance regimes. These forests are ecologically important and provide a scientifically irreplaceable system for assessing baseline ecosystem function, processes and services. As the largest remaining old-growth red pine forest in the world, Wolf Lake Forest Reserve deserves intensive study, monitoring and full protection from future development.
    BibTeX:
    @article{anand_scientific_2013,
      author = {Anand, Madhur and Leithead, Mark and Silva, Lucas C. R. and Wagner, Christopher and Ashiq, Muhammad Waseem and Cecile, Jacob and Drobyshev, Igor and Bergeron, Yves and Das, Arundhati and Bulger, Cara},
      title = {The scientific value of the largest remaining old-growth red pine forests in North America},
      journal = {Biodiversity and Conservation},
      year = {2013},
      volume = {22},
      number = {8},
      pages = {1847--1861},
      url = {https://link.springer.com/article/10.1007/s10531-013-0497-1},
      doi = {http://doi.org/10.1007/s10531-013-0497-1}
    }
    					
    borghetti_simple_2013 Borghetti, F.; Lima, E.C. d. & Silva, L. d.C.R. A simple procedure for the purification of active fractions in aqueous extracts of plants with allelopathic properties 2013 Acta Botanica Brasilica
    Vol. 27 (1) , pp. 50-53  
    article
    BibTeX:
    @article{borghetti_simple_2013,
      author = {Borghetti, Fabian and Lima, Elisa Coutinho de and Silva, Lucas de Carvalho Ramos},
      title = {A simple procedure for the purification of active fractions in aqueous extracts of plants with allelopathic properties},
      journal = {Acta Botanica Brasilica},
      year = {2013},
      volume = {27},
      number = {1},
      pages = {50--53},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0102-33062013000100007&lng=en&nrm=iso&tlng=en},
      doi = {http://doi.org/10.1590/S0102-33062013000100007}
    }
    					
    cecile_old_2013 Cecile, J.; Silva, L.R. & Anand, M. Old Trees: Large and Small 2013 Science
    Vol. 339 (6122) , pp. 904-905  
    article
    Abstract: D. B. Lindenmayer et al. ("Global decline in large old trees," Perspectives, 7 December 2012, p. [1305][1]), report a global decline in large old trees and show that climate change and human disturbance are reducing the abundance of these ecologically important organisms. Such framing of the problem
    BibTeX:
    @article{cecile_old_2013,
      author = {Cecile, Jacob and Silva, Lucas R. and Anand, Madhur},
      title = {Old Trees: Large and Small},
      journal = {Science},
      year = {2013},
      volume = {339},
      number = {6122},
      pages = {904--905},
      url = {http://science.sciencemag.org/content/339/6122/904.3},
      doi = {http://doi.org/10.1126/science.339.6122.904-c}
    }
    					
    gomez-guerrero_growth_2013 Gómez-Guerrero, A.; Silva, L.C.R.; Barrera-Reyes, M.; Kishchuk, B.; Velázquez-Martínez, A.; Martínez-Trinidad, T.; Plascencia-Escalante, F.O. & Horwath, W.R. Growth decline and divergent tree ring isotopic composition (δ13C and δ18O) contradict predictions of CO2 stimulation in high altitudinal forests 2013 Global Change Biology
    Vol. 19 (6) , pp. 1748-1758  
    article abies religiosa, climate change, co2, drought stress, high-elevation forests, mexico, pinus hartwegii, stable isotopes
    Abstract: Human-induced changes in atmospheric composition are expected to affect primary productivity across terrestrial biomes. Recent changes in productivity have been observed in many forest ecosystems, but low-latitude upper tree line forests remain to be investigated. Here, we use dendrochronological methods and isotopic analysis to examine changes in productivity, and their physiological basis, in Abies religiosa (Ar) and Pinus hartwegii (Ph) trees growing in high-elevation forests of central Mexico. Six sites were selected across a longitudinal transect (Transverse Volcanic Axis), from the Pacific Ocean toward the Gulf of Mexico, where mature dominant trees were sampled at altitudes ranging from 3200 to 4000 m asl. A total of 60 Ar and 84 Ph trees were analyzed to describe changes in growth (annual-resolution) and isotopic composition (decadal-resolution) since the early 1900s. Our results show an initial widespread increase in basal area increment (BAI) during the first half of the past century. However, BAI has decreased significantly since the 1950s with accentuated decline after the 1980s in both species and across sites. We found a consistent reduction in atmosphere to wood 13C discrimination, resulting from increasing water use efficiency (20–60, coinciding with rising atmospheric CO2. Changes in 13C discrimination were not followed, however, by shifts in tree ring δ18O, indicating site- and species-specific differences in water source or uptake strategy. Our results indicate that CO2 stimulation has not been enough to counteract warming-induced drought stress, but other stressors, such as progressive nutrient limitation, could also have contributed to growth decline. Future studies should explore the distinct role of resource limitation (water vs. nutrients) in modulating the response of high-elevation ecosystems to atmospheric change.
    BibTeX:
    @article{gomez-guerrero_growth_2013,
      author = {Gómez-Guerrero, Armando and Silva, Lucas C. R. and Barrera-Reyes, Miguel and Kishchuk, Barbara and Velázquez-Martínez, Alejandro and Martínez-Trinidad, Tomás and Plascencia-Escalante, Francisca Ofelia and Horwath, William R.},
      title = {Growth decline and divergent tree ring isotopic composition (δ13C and δ18O) contradict predictions of CO2 stimulation in high altitudinal forests},
      journal = {Global Change Biology},
      year = {2013},
      volume = {19},
      number = {6},
      pages = {1748--1758},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/gcb.12170/abstract},
      doi = {http://doi.org/10.1111/gcb.12170}
    }
    					
    haidar_seasonal_2013 Haidar, R.F.; Fagg, J.M.F.; Pinto, J.R.R.; Dias, R.R.; Damasco, G.; Silva, L. d.C.R. & Fagg, C.W. Seasonal forests and ecotone areas in the state of Tocantins, Brazil: structure, classification and guidelines for conservation 2013 Acta Amazonica
    Vol. 43 (3) , pp. 261-290  
    article
    BibTeX:
    @article{haidar_seasonal_2013,
      author = {Haidar, Ricardo Flores and Fagg, Jeanine Maria Felfili and Pinto, José Roberto Rodrigues and Dias, Ricardo Ribeiro and Damasco, Gabriel and Silva, Lucas de Carvalho Ramos and Fagg, Christopher William},
      title = {Seasonal forests and ecotone areas in the state of Tocantins, Brazil: structure, classification and guidelines for conservation},
      journal = {Acta Amazonica},
      year = {2013},
      volume = {43},
      number = {3},
      pages = {261--290},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0044-59672013000300003&lng=en&nrm=iso&tlng=pt},
      doi = {http://doi.org/10.1590/S0044-59672013000300003}
    }
    					
    ladd_estimates_2013 Ladd, B.; Laffan, S.W.; Amelung, W.; Peri, P.L.; Silva, L.C.R.; Gervassi, P.; Bonser, S.P.; Navall, M. & Sheil, D. Estimates of soil carbon concentration in tropical and temperate forest and woodland from available GIS data on three continents 2013 Global Ecology and Biogeography
    Vol. 22 (4) , pp. 461-469  
    article carbon accounting, climate, forest, geographic information systems, leaf area index, redd, soil carbon, voluntary carbon standards, woodland
    Abstract: Aim

    Concern about climate change, with the subsequent emergence of carbon markets and policy initiatives such as REDD (reducing carbon emissions by decreasing deforestation and forest degradation), have focused attention on assessing and monitoring terrestrial carbon reserves. Most effort has focused on above-ground forest biomass. Soil has received less attention despite containing more carbon than above-ground terrestrial biomass and the atmosphere combined. Our aim was to explore how well soil carbon concentration could be estimated on three continents from existing climate, topography and vegetation-cover data.

    Location

    Peru, Brazil, Argentina, Australia, China.

    Methods

    Soil carbon concentration and leaf area index (LAI) as well as GIS-derived climate and topography variables for 65 temperate and 43 tropical, forest and woodland ecosystems, were either directly measured or estimated from freely available global datasets. We then used multiple regressions to determine how well soil carbon concentration could be predicted from LAI, climate and topography at a given site. We compared our measurements with top soil carbon estimates from the Food and Agriculture Organization of the United Nations (FAO) harmonized world soil map.

    Results

    Our empirical model based on estimates of temperature, water availability and plant productivity provided a good estimate of soil carbon concentrations (R2 = 0.79). In contrast, the values of topsoil carbon concentrations from the FAO harmonized world soil map correlated poorly with the measured values of soil carbon concentration (R2 = 0.0011).

    Main conclusions

    The lack of correlation between the measured values of soil carbon and the values from the FAO harmonized world soil map indicate that substantial improvements in the production of soil carbon maps are needed and possible. Our results demonstrate that the inclusion of freely available GIS data offers improved estimates of soil carbon and will allow the creation of more accurate soil carbon maps.

    BibTeX:
    @article{ladd_estimates_2013,
      author = {Ladd, Brenton and Laffan, Shawn W. and Amelung, Wulf and Peri, Pablo L. and Silva, Lucas C. R. and Gervassi, Pina and Bonser, Stephen P. and Navall, Marcelo and Sheil, Douglas},
      title = {Estimates of soil carbon concentration in tropical and temperate forest and woodland from available GIS data on three continents},
      journal = {Global Ecology and Biogeography},
      year = {2013},
      volume = {22},
      number = {4},
      pages = {461--469},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1466-8238.2012.00799.x/abstract},
      doi = {http://doi.org/10.1111/j.1466-8238.2012.00799.x}
    }
    					
    mukome_testing_2013 Mukome, F.; Doane, T.; Silva, L.; Parikh, S. & Horwath, W. Testing protocol ensures the authenticity of organic fertilizers 2013 California Agriculture
    Vol. 67 (4) , pp. 210-216  
    article
    Abstract: There is a pressing need for methodology to confirm the authenticity of fertilizers labeled “suitable for organic production.” In this study, we developed a testing protocol that can be used by laboratories and regulatory agencies to detect adulteration of organic fertilizers and soil amendments with a synthetic nitrogen source. By conducting an extensive literature review and analysis of 180 commercially available raw materials, organic fertilizers, soil amendments and synthetic fertilizers, we compiled a comprehensive database of quantifiable properties of those materials. We analyzed their ammonium content, C:N ratio and stable nitrogen isotope ratio, and for each metric we set thresholds that flag products with a high probability of adulteration. The protocol can be used to authenticate organic fertilizer products and bring transparency to the industry.
    BibTeX:
    @article{mukome_testing_2013,
      author = {Mukome, F. and Doane, T. and Silva, L. and Parikh, S. and Horwath, W.},
      title = {Testing protocol ensures the authenticity of organic fertilizers},
      journal = {California Agriculture},
      year = {2013},
      volume = {67},
      number = {4},
      pages = {210--216},
      url = {http://calag.ucanr.edu/Archive/?article=ca.v067n04p210}
    }
    					
    mukome_use_2013 Mukome, F.N.D.; Zhang, X.; Silva, L.C.R.; Six, J. & Parikh, S.J. Use of Chemical and Physical Characteristics To Investigate Trends in Biochar Feedstocks 2013 Journal of Agricultural and Food Chemistry
    Vol. 61 (9) , pp. 2196-2204  
    article
    Abstract: Studies have shown that pyrolysis method and temperature are the key factors influencing biochar chemical and physical properties; however, information on the nature of biochar feedstocks is more accessible to consumers, making feedstock a better measure for selecting biochars. This study characterizes physical and chemical properties of commercially available biochars and investigates trends in biochar properties related to feedstock material to develop guidelines for biochar use. Twelve biochars were analyzed for physical and chemical properties. Compiled data from this study and from the literature (n = 85) were used to investigate trends in biochar characteristics related to feedstock. Analysis of compiled data reveals that despite clear differences in biochar properties from feedstocks of algae, grass, manure, nutshells, pomace, and wood (hard- and softwoods), characteristic generalizations can be made. Feedstock was a better predictor of biochar ash content and C/N ratio, but surface area was also temperature dependent for wood-derived biochar. Significant differences in ash content (grass and manure textgreater wood) and C/N ratio (softwoods textgreater grass and manure) enabled the first presentation of guidelines for biochar use based on feedstock material.
    BibTeX:
    @article{mukome_use_2013,
      author = {Mukome, Fungai N. D. and Zhang, Xiaoming and Silva, Lucas C. R. and Six, Johan and Parikh, Sanjai J.},
      title = {Use of Chemical and Physical Characteristics To Investigate Trends in Biochar Feedstocks},
      journal = {Journal of Agricultural and Food Chemistry},
      year = {2013},
      volume = {61},
      number = {9},
      pages = {2196--2204},
      url = {http://dx.doi.org/10.1021/jf3049142},
      doi = {http://doi.org/10.1021/jf3049142}
    }
    					
    ricardo_flores_haidar_florestas_2013 Haidar, R.F.; Fagg, J.M.F.; Pinto, J.R.R.; Dias, R.R.; Damasco, G.; de Carvalho Ramos Silva, L. & Fagg, C.W. Florestas estacionais e áreas de ecótono no estado do Tocantins, Brasil&58; parČmetros estruturais, classificaćčo das fitofisionomias florestais e subsídios para conservaćčo Seasonal forests and ecotone areas in the state of Tocantins, Brazil&58; structure, classification and guidelines for conservation 2013 Acta Amazonica
    Vol. 43 (3) , pp. 261-290  
    article
    Abstract: O objetivo deste estudo foi descrever a riqueza, estrutura e diversidade de espécies arbóreas em áreas de Floresta Estacional e ecótono (Floresta Estacional/Floresta Ombrófila) no estado do Tocantins, buscando subsídios para a conservaćčo, manejo florestal, compensaćčo de reserva legal e recuperaćčo ambiental, além de discutir as identidades fitogeográficas em comparaćčo com outras florestas do Brasil. Em 18 bacias hidrográficas, conduziu-se amostragem da vegetaćčo arbórea (DAP &62; 5 cm) de 22 áreas (amostras) por meio do inventário de 477 parcelas de 400 m2. Foram elaboradas análises de classificaćčo pelo método TWINSPAN, em duas escalas distintas. A primeira avaliou a diversidade beta entre as parcelas amostradas no estado do Tocantins e a segunda buscou analisar a similaridade das florestas do Tocantins em relaćčo a outras florestas do bioma Cerrado e suas áreas de tensčo ecológica. As florestas amostradas apresentaram ampla variaćčo em termos de riqueza (33 a 243 espécies), densidade (486 a 1.179 ind.ha-1), área basal (14,04 e 37,49 m2.ha-1), índices de diversidade (Hę &61; 2,75 a 4,59) e de equabilidade (Ję&61; 0,72 a 0,86). As análises de classificaćčo convergiram para resultados comuns, identificando quatro ambientes dissimilares em termos florísticos e estruturais no estado do Tocantins&58; Floresta Estacional Decidual, Floresta Estacional Semidecidual, ecótono Floresta Estacional Semidecidual/Floresta Ombrófila e ecótono Floresta Estacional Decidual/Floresta Ombrófila. A fim de manter a diversidade de plantas e de ambientes na regičo de transićčo Floresta Amazônica e Cerrado, sugere-se que o processo de criaćčo de unidades de conservaćčo no estado do Tocantins deva ser intensificado e tenha como base para selećčo das áreas critérios biogeográficos.&60;br&62;The purpose of this study was to describe the richness, structure and diversity of tree species occurring in seasonally dry forests and some ecotone areas (Seasonal Forest/Ombrophilous Forest) in the state of Tocantins (Brazil). We aimed to provide information for conservation, management, environmental compensation and restoration strategies, and discuss their phytogeography identities in relation to other Brazilian forests. We selected 22 areas in 18 hydrogeographic basins and performed an inventory of all trees species (DHB &62; 5 cm) occurring in 477 plots of 400 m2. We conducted a classification analysis of the vegetation using the TWINSPAN method in two different scales. The first assessed the beta diversity among plots within the state of Tocantins, and the second analysed similarities between these forests and other forests ecosystems in the Cerrado ecoregion and related ecotones in Central Brazil. A wide variation of species richness (33 to 243 species), density (486 to 1179 trees.ha-1), basal area (14.04 to 37.49 m2. ha-1), diversity indexes (H’ &61; 2.75 to 4.59) and evenness (J’ &61; 0.72 to 0.86) across the sites was found. Based on floristic and structural aspects, classification analyses identified four major forests types&58; Seasonal Deciduous Forest, Seasonal Semi-deciduous Forest, and two ecotones Seasonal Semideciduous Forest/Ombrophilous Forest and ecotone Seasonal Deciduous Forest / Ombrophilous Forest. In order to maintain plant and habitat diversity in the Amazon/Cerrado transition zone, the creation of conservation areas should be intensified using biogeographical patterns as site selection criteria.
    BibTeX:
    @article{ricardo_flores_haidar_florestas_2013,
      author = {Ricardo Flores Haidar and Jeanine Maria Felfili Fagg and José Roberto Rodrigues Pinto and Ricardo Ribeiro Dias and Gabriel Damasco and Lucas de Carvalho Ramos Silva and Christopher William Fagg},
      title = {Florestas estacionais e áreas de ecótono no estado do Tocantins, Brasil&58; parČmetros estruturais, classificaćčo das fitofisionomias florestais e subsídios para conservaćčo Seasonal forests and ecotone areas in the state of Tocantins, Brazil&58; structure, classification and guidelines for conservation},
      journal = {Acta Amazonica},
      year = {2013},
      volume = {43},
      number = {3},
      pages = {261--290}
    }
    					
    rossatto_seasonal_2013 Rossatto, D.R.; Hoffmann, W.A.; Silva, L. d.C.R.; Haridasan, M.; Sternberg, L.S.L. & Franco, A.C. Seasonal variation in leaf traits between congeneric savanna and forest trees in Central Brazil: implications for forest expansion into savanna 2013 Trees
    Vol. 27 (4) , pp. 1139-1150  
    article
    Abstract: The ecology of forest and savanna trees species will largely determine the structure and dynamics of the forest–savanna boundaries, but little is known about the constraints to leaf trait variation imposed by selective forces and evolutionary history during the process of savanna invasion by forest species. We compared seasonal patterns in leaf traits related to leaf structure, carbon assimilation, water, and nutrient relations in 10 congeneric species pairs, each containing one savanna species and one forest species. All individuals were growing in dystrophic oxisols in a fire-protected savanna of Central Brazil. We tested the hypothesis that forest species would be more constrained by seasonal drought and nutrient-poor soils than their savanna congeners. We also hypothesized that habitat, rather than phylogeny, would explain more of the interspecific variance in leaf traits of the studied species. We found that throughout the year forest trees had higher specific leaf area (SLA) but lower integrated water use efficiency than savanna trees. Forest and savanna species maintained similar values of predawn and midday leaf water potential along the year. Lower values were measured in the dry season. However, this was achieved by a stronger regulation of stomatal conductance and of CO2 assimilation on an area basis (Aarea) in forest trees, particularly toward the end of the dry season. Relative to savanna trees, forest trees maintained similar (P, K, Ca, and Mg) or slightly higher (N) leaf nutrient concentrations. For the majority of traits, more variance was explained by phylogeny, than by habitat of origin, with the exception of SLA, leaf N concentration, and Aarea, which were apparently subjected to different selective pressures in the savanna and forest environments. In conclusion, water shortage during extended droughts would be more limiting for forest trees than nutrient-poor soils.
    BibTeX:
    @article{rossatto_seasonal_2013,
      author = {Rossatto, Davi Rodrigo and Hoffmann, William Arthur and Silva, Lucas de Carvalho Ramos and Haridasan, Mundayatan and Sternberg, Leonel S. L. and Franco, Augusto César},
      title = {Seasonal variation in leaf traits between congeneric savanna and forest trees in Central Brazil: implications for forest expansion into savanna},
      journal = {Trees},
      year = {2013},
      volume = {27},
      number = {4},
      pages = {1139--1150},
      url = {https://link.springer.com/article/10.1007/s00468-013-0864-2},
      doi = {http://doi.org/10.1007/s00468-013-0864-2}
    }
    					
    silva_can_2013 Silva, L.C.R.; Hoffmann, W.A.; Rossatto, D.R.; Haridasan, M.; Franco, A.C. & Horwath, W.R. Can savannas become forests? A coupled analysis of nutrient stocks and fire thresholds in central Brazil 2013 Plant and Soil
    Vol. 373 (1-2) , pp. 829-842  
    article
    Abstract: AimsThe effects of fire ensure that large areas of the seasonal tropics are maintained as savannas. The advance of forests into these areas depends on shifts in species composition and the presence of sufficient nutrients. Predicting such transitions, however, is difficult due to a poor understanding of the nutrient stocks required for different combinations of species to resist and suppress fires.MethodsWe compare the amounts of nutrients required by congeneric savanna and forest trees to reach two thresholds of establishment and maintenance: that of fire resistance, after which individual trees are large enough to survive fires, and that of fire suppression, after which the collective tree canopy is dense enough to minimize understory growth, thereby arresting the spread of fire. We further calculate the arboreal and soil nutrient stocks of savannas, to determine if these are sufficient to support the expansion of forests following initial establishment.ResultsForest species require a larger nutrient supply to resist fires than savanna species, which are better able to reach a fire-resistant size under nutrient limitation. However, forest species require a lower nutrient supply to attain closed canopies and suppress fires; therefore, the ingression of forest trees into savannas facilitates the transition to forest. Savannas have sufficient N, K, and Mg, but require additional P and Ca to build high-biomass forests and allow full forest expansion following establishment.ConclusionsTradeoffs between nutrient requirements and adaptations to fire reinforce savanna and forest as alternate stable states, explaining the long-term persistence of vegetation mosaics in the seasonal tropics. Low-fertility limits the advance of forests into savannas, but the ingression of forest species favors the formation of non-flammable states, increasing fertility and promoting forest expansion.
    BibTeX:
    @article{silva_can_2013,
      author = {Silva, Lucas C. R. and Hoffmann, William A. and Rossatto, Davi R. and Haridasan, Mundayatan and Franco, Augusto C. and Horwath, William R.},
      title = {Can savannas become forests? A coupled analysis of nutrient stocks and fire thresholds in central Brazil},
      journal = {Plant and Soil},
      year = {2013},
      volume = {373},
      number = {1-2},
      pages = {829--842},
      url = {https://link.springer.com/article/10.1007/s11104-013-1822-x},
      doi = {http://doi.org/10.1007/s11104-013-1822-x}
    }
    					
    silva_explaining_2013 Silva, L.C.R. & Horwath, W.R. Explaining Global Increases in Water Use Efficiency: Why Have We Overestimated Responses to Rising Atmospheric CO2 in Natural Forest Ecosystems? 2013 PLOS ONE
    Vol. 8 (1) , pp. e53089  
    article biomass (ecology), carbon dioxide, dendrology, ecosystems, monte carlo method, plant physiology, simulation and modeling, trees
    Abstract: Background The analysis of tree-ring carbon isotope composition (δ13C) has been widely used to estimate spatio-temporal variations in intrinsic water use efficiency (iWUE) of tree species. Numerous studies have reported widespread increases in iWUE coinciding with rising atmospheric CO2 over the past century. While this could represent a coherent global response, the fact that increases of similar magnitude were observed across biomes with no apparent effect on tree growth raises the question of whether iWUE calculations reflect actual physiological responses to elevated CO2 levels. Methodology/Results Here we use Monte Carlo simulations to test if an artifact of calculation could explain observed increases in iWUE. We show that highly significant positive relationships between iWUE and CO2 occur even when simulated data (randomized δ13C values spanning the observed range) are used in place of actual tree-ring δ13C measurements. From simulated data sets we calculated non-physiological changes in iWUE from 1900 to present and across a 4000 m altitudinal range. This generated results strikingly similar to those reported in recent studies encompassing 22 species from tropical, subtropical, temperate, boreal and mediterranean ecosystems. Only 6 of 49 surveyed case studies showed increases in iWUE significantly higher than predicted from random values. Conclusions/Significance Our results reveal that increases in iWUE estimated from tree-ring δ13C occur independently of changes in 13C discrimination that characterize physiological responses to elevated CO2. Due to a correlation with CO2 concentration, which is used as an independent factor in the iWUE calculation, any tree-ring δ13C data set would inevitably generate increasing iWUE over time. Therefore, although consistent, previously reported trends in iWUE do not necessarily reflect a coherent global response to rising atmospheric CO2. We discuss the significance of these findings and suggest ways to distinguish real from artificial responses in future studies.
    BibTeX:
    @article{silva_explaining_2013,
      author = {Silva, Lucas C. R. and Horwath, William R.},
      title = {Explaining Global Increases in Water Use Efficiency: Why Have We Overestimated Responses to Rising Atmospheric CO2 in Natural Forest Ecosystems?},
      journal = {PLOS ONE},
      year = {2013},
      volume = {8},
      number = {1},
      pages = {e53089},
      url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0053089},
      doi = {http://doi.org/10.1371/journal.pone.0053089}
    }
    					
    silva_historical_2013 Silva, L. & Anand, M. Historical links and new frontiers in the study of forest-atmosphere interactions 2013 Community Ecology
    Vol. 14 (2) , pp. 208-218  
    article
    Abstract: Forest biomes have expanded and contracted in response to past climate fluctuations, but it is not clear how they will respond to human-induced atmospheric change. We provide a review of the literature, describing historical links between biogeographical and atmospheric patterns, comparing characteristics of forest biomes and describing expected changes in climate forcings from observed range shifts. Over the geological history, climate fluctuations prompted changes in forest distribution that, in turn, stabilized the atmosphere. Over the past century, warming-induced stress has caused widespread declines of mature forests, but new forests have expanded into open areas of boreal, tropical and temperate regions. Historically, forest expansion happened at much faster rates in cold than in warm regions. Across biomes, species interactions control the use of limiting resources, regulating community dynamics and expansion rates in response to climate variability. Modern impacts of land use change on the distribution of forest biomes are well understood, but the expansion of new forests and their role in stabilizing the atmosphere are yet to be accounted for in global models. Expansion of tropical and temperate forests would yield a negative climate forcing through increased carbon sequestration and evaporative cooling, but in the boreal region forest expansion could amplify climate warming due to changes in albedo. Although qualitative descriptions of forest-atmosphere interactions are possible based on existing records, the net climate forcing from forest range shifts remains uncertain. Three critical gaps in knowledge hinder rigorous evaluations of causality necessary to probe for linkages between climatic and biogeographical patterns: (i) reconstructions of vegetation dynamics have not sufficiently represented warm biomes; (ii) climate and vegetation dynamics are typically assessed at non-comparable scales; and (iii) single-proxies are normally used to simultaneously infer changes in climate and vegetation distribution, leading to redundancy in interpretation. Addressing these issues would improve our ability to decipher past and predict future outcomes of forest-atmosphere interactions.
    BibTeX:
    @article{silva_historical_2013,
      author = {Silva, L. and Anand, M.},
      title = {Historical links and new frontiers in the study of forest-atmosphere interactions},
      journal = {Community Ecology},
      year = {2013},
      volume = {14},
      number = {2},
      pages = {208--218},
      url = {http://akademiai.com/doi/abs/10.1556/ComEc.14.2013.2.11},
      doi = {http://doi.org/10.1556/ComEc.14.2013.2.11}
    }
    					
    silva_probing_2013 Silva, L.C.R. & Anand, M. Probing for the influence of atmospheric CO2 and climate change on forest ecosystems across biomes 2013 Global Ecology and Biogeography
    Vol. 22 (1) , pp. 83-92  
    article 2, atmospheric co, climate change, dendroecology, productivity, stable isotopes, tree rings
    Abstract: Aim

    Rising atmospheric CO
    2 and climate warming have induced changes in tree growth and intrinsic water-use efficiency (iWUE) world-wide, but the long-term impact of such changes on terrestrial productivity remains unknown. Based on a synthesis of the literature, here we investigate the net impact of recent atmospheric changes across forest biomes.

    Location

    A range of sites covering major forest biomes.

    Methods

    We use dendrochronological and isotopic records to provide an integrated analysis of changes in growth and iWUE, evaluating the impacts of atmospheric changes in tree growth. In our analysis, positive relationships between changes in growth and iWUE reflect CO
    2 stimulation, while neutral effects yield inflections in growth curves (plotted against iWUE), and negative relationships indicate the prevalence of stressors. To estimate net effects (since 1960) and compare responses across biomes, we use a response contrast (RC) index, based on the ratio between cumulative changes in growth and iWUE.

    Results

    In 37 recently published case studies changes in iWUE were consistently positive, increasing by between 10 and 60 but shifts in growth varied widely within and among forest biomes. Positive RC values were observed in high latitudes (>40°N), while progressively lower (always negative) responses were observed toward lower latitudes. Growth rates declined between 15 and 55% in tropical forests. In subtropical sites growth declined by between 7 and 10 while mixed responses occurred in other regions.

    Main conclusions

    Over the past 50 years, tree growth decline has prevailed despite increasing atmospheric CO
    2. The impact of atmospheric changes on forest productivity is latitude dependent (R
    2 = 0.9, P < 0.05), but our results suggest that, globally, CO
    2 stimulation of mature trees will not counteract emissions. In most surveyed case studies warming-induced stress was evoked to explain growth decline, but other factors, such as nutrient limitation, could have overridden the potential benefits of rising CO
    2 levels.

    BibTeX:
    @article{silva_probing_2013,
      author = {Silva, Lucas C. R. and Anand, Madhur},
      title = {Probing for the influence of atmospheric CO2 and climate change on forest ecosystems across biomes},
      journal = {Global Ecology and Biogeography},
      year = {2013},
      volume = {22},
      number = {1},
      pages = {83--92},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1466-8238.2012.00783.x/abstract},
      doi = {http://doi.org/10.1111/j.1466-8238.2012.00783.x}
    }
    					
    silva_unprecedented_2013 Silva, L.C.R.; Corrźa, R.S.; Doane, T.A.; Pereira, E.I.P. & Horwath, W.R. Unprecedented carbon accumulation in mined soils: the synergistic effect of resource input and plant species invasion 2013 Ecological Applications
    Vol. 23 (6) , pp. 1345-1356  
    article alternative equilibria, carbon sequestration, central brazil, land restoration, mines, resource-ratio theory, soil–plant feedback, stable isotope, succession
    Abstract: Opencast mining causes severe impacts on natural environments, often resulting in permanent damage to soils and vegetation. In the present study we use a 14-year restoration chronosequence to investigate how resource input and spontaneous plant colonization promote the revegetation and reconstruction of mined soils in central Brazil. Using a multi-proxy approach, combining vegetation surveys with the analysis of plant and soil isotopic abundances (δ13C and δ15N) and chemical and physical fractionation of organic matter in soil profiles, we show that: (1) after several decades without vegetation cover, the input of nutrient-rich biosolids into exposed regoliths prompted the establishment of a diverse plant community (textgreater30 species); (2) the synergistic effect of resource input and plant colonization yielded unprecedented increases in soil carbon, accumulating as chemically stable compounds in occluded physical fractions and reaching much higher levels than observed in undisturbed ecosystems; and (3) invasive grasses progressively excluded native species, limiting nutrient availability, but contributing more than 65% of the total accumulated soil organic carbon. These results show that soil–plant feedbacks regulate the amount of available resources, determining successional trajectories and alternative stable equilibria in degraded areas undergoing restoration. External inputs promote plant colonization, soil formation, and carbon sequestration, at the cost of excluding native species. The introduction of native woody species would suppress invasive grasses and increase nutrient availability, bringing the system closer to its original state. However, it is difficult to predict whether soil carbon levels could be maintained without the exotic grass cover. We discuss theoretical and practical implications of these findings, describing how the combination of resource manipulation and management of invasive species could be used to optimize restoration strategies, counteracting soil degradation while maintaining species diversity.
    BibTeX:
    @article{silva_unprecedented_2013,
      author = {Silva, Lucas C. R. and Corrźa, Rodrigo S. and Doane, Timothy A. and Pereira, Engil I. P. and Horwath, William R.},
      title = {Unprecedented carbon accumulation in mined soils: the synergistic effect of resource input and plant species invasion},
      journal = {Ecological Applications},
      year = {2013},
      volume = {23},
      number = {6},
      pages = {1345--1356},
      url = {http://onlinelibrary.wiley.com/doi/10.1890/12-1957.1/abstract},
      doi = {http://doi.org/10.1890/12-1957.1}
    }
    					
    zhu_iron:_2013 Zhu, X.; Silva, L.C.R.; Doane, T.A. & Horwath, W.R. Iron: The Forgotten Driver of Nitrous Oxide Production in Agricultural Soil 2013 PLOS ONE
    Vol. 8 (3) , pp. e60146  
    article agricultural soil science, agriculture, centrifugation, fertilizers, finite element analysis, linear regression analysis, multivariate analysis, nitrates
    Abstract: In response to rising interest over the years, many experiments and several models have been devised to understand emission of nitrous oxide (N2O) from agricultural soils. Notably absent from almost all of this discussion is iron, even though its role in both chemical and biochemical reactions that generate N2O was recognized well before research on N2O emission began to accelerate. We revisited iron by exploring its importance alongside other soil properties commonly believed to control N2O production in agricultural systems. A set of soils from California's main agricultural regions was used to observe N2O emission under conditions representative of typical field scenarios. Results of multivariate analysis showed that in five of the twelve different conditions studied, iron ranked higher than any other intrinsic soil property in explaining observed emissions across soils. Upcoming studies stand to gain valuable information by considering iron among the drivers of N2O emission, expanding the current framework to include coupling between biotic and abiotic reactions.
    BibTeX:
    @article{zhu_iron:_2013,
      author = {Zhu, Xia and Silva, Lucas C. R. and Doane, Timothy A. and Horwath, William R.},
      title = {Iron: The Forgotten Driver of Nitrous Oxide Production in Agricultural Soil},
      journal = {PLOS ONE},
      year = {2013},
      volume = {8},
      number = {3},
      pages = {e60146},
      url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0060146},
      doi = {http://doi.org/10.1371/journal.pone.0060146}
    }
    					
    zhu_quantifying_2013 Zhu, X.; Silva, L.C.R.; Doane, T.A.; Wu, N. & Horwath, W.R. Quantifying the Effects of Green Waste Compost Application, Water Content and Nitrogen Fertilization on Nitrous Oxide Emissions in 10 Agricultural Soils 2013 Journal of Environmental Quality
    Vol. 42 (3) , pp. 912-918  
    article
    BibTeX:
    @article{zhu_quantifying_2013,
      author = {Zhu, Xia and Silva, Lucas C. R. and Doane, Timothy A. and Wu, Ning and Horwath, William R.},
      title = {Quantifying the Effects of Green Waste Compost Application, Water Content and Nitrogen Fertilization on Nitrous Oxide Emissions in 10 Agricultural Soils},
      journal = {Journal of Environmental Quality},
      year = {2013},
      volume = {42},
      number = {3},
      pages = {912--918},
      url = {https://dl.sciencesocieties.org/publications/jeq/abstracts/42/3/912},
      doi = {http://doi.org/10.2134/jeq2012.0445}
    }
    					
    carvalho_leishmania_2012 Carvalho, S.; Silva, R.; Shawki, A.; Mackenzie, B.; Castro, H.; Eide, D.; Costa, V. & Tomás, A.M. Leishmania infantum ZIP3 is a zinc transporter that is tightly regulated by zinc status 2012 The FASEB Journal
    Vol. 26 (1 Supplement) , pp. 1112.4-1112.4  
    article
    Abstract: The ZIP family comprises proteins involved in transport of divalent metals in many organisms. Among three putative ZIP members in L. infantum, we have identified LiZIP3 as a protein involved in the acquisition of zinc since (1) expression of LiZIP3 in a yeast strain defective in zinc acquisition systems rescued the growth in zinc-limiting medium and (2) expression of LiZIP3 in Xenopus laevis oocytes modestly stimulated the uptake of 65Zn2+.
    In L. infantum, LiZIP3 expression was induced in the presence of the metal chelator EDTA and decreased following the addition of zinc. Furthermore, we found that, whereas the protein was present at the surface of the parasite under zinc-limiting conditions, LiZIP3 level decreased after 24 hours of zinc supplementation and membrane localization was lost. LiZIP3 mRNA levels increased when parasites were grown in low-zinc medium and decreased within one hour following zinc addition, indicating that regulation of LiZIP3 expression is mediated largely at the level of mRNA stability. We observed no LiZIP3 mRNA down-regulation in response to zinc when we inhibited protein synthesis, implicating a labile protein in the destabilization of the mRNA when zinc is available.
    Together, our data suggest that LiZIP3 is a zinc transporter - the first identified in Leishmania - and that its expression is tightly regulated by zinc status.
    Financial support – FCT, NIDDK, Univ.Cincinnati, NCI
    BibTeX:
    @article{carvalho_leishmania_2012,
      author = {Carvalho, Sandra and Silva, Rosa and Shawki, Ali and Mackenzie, Bryan and Castro, Helena and Eide, David and Costa, Vítor and Tomás, Ana M.},
      title = {Leishmania infantum ZIP3 is a zinc transporter that is tightly regulated by zinc status},
      journal = {The FASEB Journal},
      year = {2012},
      volume = {26},
      number = {1 Supplement},
      pages = {1112.4--1112.4},
      url = {http://www.fasebj.org/content/26/1_Supplement/1112.4}
    }
    					
    hoffmann_ecological_2012 Hoffmann, W.A.; Geiger, E.L.; Gotsch, S.G.; Rossatto, D.R.; Silva, L.C.R.; Lau, O.L.; Haridasan, M. & Franco, A.C. Ecological thresholds at the savanna-forest boundary: how plant traits, resources and fire govern the distribution of tropical biomes 2012 Ecology Letters
    Vol. 15 (7) , pp. 759-768  
    article alternate stable states, critical thresholds, forest, savanna, tipping point
    Abstract: Fire shapes the distribution of savanna and forest through complex interactions involving climate, resources and species traits. Based on data from central Brazil, we propose that these interactions are governed by two critical thresholds. The fire-resistance threshold is reached when individual trees have accumulated sufficient bark to avoid stem death, whereas the fire-suppression threshold is reached when an ecosystem has sufficient canopy cover to suppress fire by excluding grasses. Surpassing either threshold is dependent upon long fire-free intervals, which are rare in mesic savanna. On high-resource sites, the thresholds are reached quickly, increasing the probability that savanna switches to forest, whereas low-resource sites are likely to remain as savanna even if fire is infrequent. Species traits influence both thresholds; saplings of savanna trees accumulate bark thickness more quickly than forest trees, and are more likely to become fire resistant during fire-free intervals. Forest trees accumulate leaf area more rapidly than savanna trees, thereby accelerating the transition to forest. Thus, multiple factors interact with fire to determine the distribution of savanna and forest by influencing the time needed to reach these thresholds. Future work should decipher multiple environmental controls over the rates of tree growth and canopy closure in savanna.
    BibTeX:
    @article{hoffmann_ecological_2012,
      author = {Hoffmann, William A. and Geiger, Erika L. and Gotsch, Sybil G. and Rossatto, Davi R. and Silva, Lucas C. R. and Lau, On Lee and Haridasan, M. and Franco, Augusto C.},
      title = {Ecological thresholds at the savanna-forest boundary: how plant traits, resources and fire govern the distribution of tropical biomes},
      journal = {Ecology Letters},
      year = {2012},
      volume = {15},
      number = {7},
      pages = {759--768},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2012.01789.x/abstract},
      doi = {http://doi.org/10.1111/j.1461-0248.2012.01789.x}
    }
    					
    leithead_recruitment_2012 Leithead, M.; Silva, L.C.R. & Anand, M. Recruitment patterns and northward tree migration through gap dynamics in an old-growth white pine forest in northern Ontario 2012 Plant Ecology
    Vol. 213 (11) , pp. 1699-1714  
    article
    Abstract: Decreases in abundances and declines in growth of eastern white pine over the past century due mainly to human activities have resulted in few large intact old-growth white pine forests in Ontario. These stands may be vulnerable to replacement by deciduous species from temperate forests further south, where recruitment in canopy gap disturbances can greatly define the regeneration process. We investigated recruitment dynamics in canopy gaps of an old-growth white pine forest of Temagami, northern Ontario, Canada, the northern limit of the temperate–boreal ecotone. White pine, red pine, black spruce and eastern white cedar represented 85 % of the mature canopy abundance, where trees and saplings established equally in gaps and the closed canopy. Balsam fir and paper birch were more abundant in gaps, showing increases of abundance and basal area with increases in gap size representing canopy self-replacement (balsam fir) and autogenic succession (paper birch). Red maple, at its northernmost range limit, was the only species to show linear increases of abundance and basal area with increases in gap size and gap age. This result, along with adult red maples present in gaps but absent from the closed canopy, identifies the establishment of a northward migrating species in gaps as hypothesized for pine forests at the northern limit of this broad ecotone. We discuss how migration pressures, coupled with pine recruitment limitation through reduced fire frequency by regional fire suppression and predicted future increased warming of 2–4 °C over the next century, threatens replacement of old-growth white pine forests at this latitude with northward migrating tree species found further south.
    BibTeX:
    @article{leithead_recruitment_2012,
      author = {Leithead, Mark and Silva, Lucas C. R. and Anand, Madhur},
      title = {Recruitment patterns and northward tree migration through gap dynamics in an old-growth white pine forest in northern Ontario},
      journal = {Plant Ecology},
      year = {2012},
      volume = {213},
      number = {11},
      pages = {1699--1714},
      url = {https://link.springer.com/article/10.1007/s11258-012-0116-3},
      doi = {http://doi.org/10.1007/s11258-012-0116-3}
    }
    					
    rossatto_depth_2012 Rossatto, D.R.; de Carvalho Ramos Silva, L.; Villalobos-Vega, R.; Sternberg, L. d.S.L. & Franco, A.C. Depth of water uptake in woody plants relates to groundwater level and vegetation structure along a topographic gradient in a neotropical savanna 2012 Environmental and Experimental Botany
    Vol. 77 (Supplement C) , pp. 259-266  
    article savanna, stable isotopes, topographic gradient, vegetation structure, water uptake
    Abstract: Vegetation structure of the savannas is variable across the landscape, ranging from open grassland to savanna woodland within topographic gradients of a few hundred meters in length. Here we investigated whether patterns of soil water extraction by the woody layer and vegetation structure changed in response to groundwater depth. We determined depth of plant water uptake, groundwater level and vegetation structure on five different locations along a topographic gradient in the highlands of Central Brazil. The elevation gradient of about 110m covered all vegetation physiognomies generally associated with topographic gradients in savannas of Central Brazil. To estimate the depth of plant water uptake in the different slope positions we relied on comparisons of hydrogen and oxygen isotope ratios of plant stem water, water from different soil depths, from groundwater and from rainfall. We subsequently used a stable isotope mixing model to estimate vertical partitioning of soil water by woody plants along the elevation gradient. We were able to show that groundwater level affected plant water uptake patterns and soil water partitioning among savanna woody species. Vegetation at higher elevation extracted water from deeper unsaturated soils and had greater variability in water uptake strategies, which was coupled to a denser and more complex woody layer. Plants on these soils used stored water from both shallow (textless0.6m) and deep (0.6–2.00m) soil layers. At lower elevation sites, however, the presence of a water table near the soil surface restricted water uptake to the shallower wet season unsaturated zone of the soil profile. The sparser woody vegetation is probably composed of species that only rely in superficial water uptake, or are plastic in relation to root characteristics.
    BibTeX:
    @article{rossatto_depth_2012,
      author = {Rossatto, Davi Rodrigo and de Carvalho Ramos Silva, Lucas and Villalobos-Vega, Randoll and Sternberg, Leonel da Silveira Lobo and Franco, Augusto César},
      title = {Depth of water uptake in woody plants relates to groundwater level and vegetation structure along a topographic gradient in a neotropical savanna},
      journal = {Environmental and Experimental Botany},
      year = {2012},
      volume = {77},
      number = {Supplement C},
      pages = {259--266},
      url = {http://www.sciencedirect.com/science/article/pii/S0098847211003066},
      doi = {http://doi.org/10.1016/j.envexpbot.2011.11.025}
    }
    					
    silva_evidence_2011 Silva, L.C.R.; Giorgis, M.A.; Anand, M.; Enrico, L.; Pérez-Harguindeguy, N.; Falczuk, V.; Tieszen, L.L. & Cabido, M. Evidence of shift in C4 species range in central Argentina during the late Holocene 2011 Plant and Soil
    Vol. 349 (1-2) , pp. 261-279  
    article
    Abstract: AimMillennial-scale biogeographic changes are well understood in many parts of the world, but little is known about long-term vegetation dynamics in subtropical regions. Here we investigate shifts in C3/C4 plant abundance occurred in central Argentina during the past few millenniaMethodsWe determined present day soil organic matter δ13C signatures of grasslands, shrublands and woodlands, containing different mixtures of C3 and C4 plants. We measured past changes in the relative cover of C3/C4 plants by comparing δ13C values in soil profiles with present day δ13C signatures. We analyzed 14C activity in soil depths that showed major changes in vegetation.ResultsPresent day relative cover of C3/C4 plants determines whole ecosystem δ13C signatures integrated as litter and superficial soil organic matter (R2 = 0.78; p textless 0.01). Deeper soils show a consistent shift in δ13C, indicating a continuous replacement of C4 by C3 plants since 3,870 (Ī210) YBP. During this period, the relative abundance of C3 plants increased 32% (average across sites) with significant changes being observed in all studied ecosystems.ConclusionsOur results show that C4 species were more abundant in the past, but C3 species became dominant during the late Holocene. We identified increases in the relative C3/C4 cover in grasslands, shrublands and woodlands, suggesting a physiological basis for changes in vegetation. The replacement of C4 by C3 plants coincided with changes in climate towards colder and wetter conditions and could represent a climatically driven shift in the C4 species optimum range.
    BibTeX:
    @article{silva_evidence_2011,
      author = {Silva, Lucas C. R. and Giorgis, Melisa A. and Anand, Madhur and Enrico, Lucas and Pérez-Harguindeguy, Natalia and Falczuk, Valeria and Tieszen, Larry L. and Cabido, Marcelo},
      title = {Evidence of shift in C4 species range in central Argentina during the late Holocene},
      journal = {Plant and Soil},
      year = {2011},
      volume = {349},
      number = {1-2},
      pages = {261--279},
      url = {https://link.springer.com/article/10.1007/s11104-011-0868-x},
      doi = {http://doi.org/10.1007/s11104-011-0868-x}
    }
    					
    silva_mechanisms_2011 Silva, L.C.R. & Anand, M. Mechanisms of Araucaria (Atlantic) Forest Expansion into Southern Brazilian Grasslands 2011 Ecosystems
    Vol. 14 (8) , pp. 1354-1371  
    article
    Abstract: Recent studies have shown that tropical and subtropical forests expanded during the late Holocene, but rates and mechanisms of expansion are still unknown. Here, we investigate how a forest–grassland mosaic changed over the past 10,000 years at the southernmost limit of the Brazilian Atlantic forest. We used soil organic matter carbon isotopes (δ13C and 14C) to quantify and date changes in vegetation, examining soil properties and leaf traits of tree species (nutrient content, δ13C, δ15N, and specific leaf area—SLA) to describe potential mechanisms of expansion. Our results show that after several millennia of stability, forests have been expanding over grasslands through continuous, but very slow, border dynamics and patch formation (textless100 m since ˜4,000 YBP). This process of expansion coincided with past changes in climate, but biotic feedback mechanisms also appear to be important for the long-term persistence and expansion of forests. Soil fertility and microbial biomass match current rather than past vegetation distribution, increasing progressively across the gradient: grasslands textless isolated trees textless forest patches textless forests. Foliar δ15N values of trees that are able to colonize the grassland are consistently lower across this vegetation gradient, suggesting an increasingly greater reliance on symbiotic nutrient uptake from grasslands to forests. No significant relationships were found between soil and leaf nutrients, but SLA explained variation in leaf N, P, and K (positive relationships) and in leaf δ13C (negative relationship). These findings suggest that a tradeoff between tree growth and water use efficiency is an important regulator of forest–grassland dynamics in the study region.
    BibTeX:
    @article{silva_mechanisms_2011,
      author = {Silva, Lucas C. R. and Anand, Madhur},
      title = {Mechanisms of Araucaria (Atlantic) Forest Expansion into Southern Brazilian Grasslands},
      journal = {Ecosystems},
      year = {2011},
      volume = {14},
      number = {8},
      pages = {1354--1371},
      url = {https://link.springer.com/article/10.1007/s10021-011-9486-y},
      doi = {http://doi.org/10.1007/s10021-011-9486-y}
    }
    					
    correa_fertilidade_2010 Correa, R.; Silva, L.; Baptista, G.; , P. & Dos Santos, F. Fertilidade química de um substrato tratado com lodo de esgoto e composto de resíduos domésticos 2010
    Vol. 14  
    book
    Abstract: O aproveitamento de resíduos urbanos como fontes de matéria orgČnica e nutrientes contribui para diminuir a pressčo das sociedades modernas sobre o meio ambiente. Por outro lado, a incorporaćčo de matéria orgČnica é um meio de se criarem condićões edáficas para o estabelecimento de plantas em solos degradados e substratos expostos. Este trabalho visou avaliar a fertilidade e a cobertura vegetal (Paspalum notatum var. saurae Parodi) de um substrato exposto ą superfície, tratado com doses crescentes (0 - 76 Mg ha-1, base seca) de lodo de esgoto ou composto de resíduos domésticos. Os resultados indicam que o lodo de esgoto foi capaz de aumentar a CTC e as concentraćões de N, P e Zn no substrato enquanto nčo houve incrementos significativos desses nutrientes no substrato tratado com o composto de resíduos domésticos. A cobertura vegetal do substrato variou de 68 a 96% nos tratamentos com lodo (resposta assintótica) e entre 22 e 67% nos tratamentos com composto (resposta linear), de acordo com a dose aplicada. Valores de CTC e concentraćões de N, P e Zn explicaram 94% da variaćčo da cobertura vegetal sobre a superfície da área.
    BibTeX:
    @book{correa_fertilidade_2010,
      author = {Correa, Rodrigo and Silva, Lucas and Baptista, Gustavo and , Perseu and Dos Santos, F},
      title = {Fertilidade química de um substrato tratado com lodo de esgoto e composto de resíduos domésticos},
      year = {2010},
      volume = {14},
      note = {DOI: 10.1590/S1415-43662010000500012}
    }
    					
    leithead_northward_2010 Leithead, M.D.; Anand, M. & Silva, L.C.R. Northward migrating trees establish in treefall gaps at the northern limit of the temperate–boreal ecotone, Ontario, Canada 2010 Oecologia
    Vol. 164 (4) , pp. 1095-1106  
    article
    Abstract: Climate change is expected to promote migration of species. In ecotones, areas of ecological tension, disturbances may provide opportunities for some migrating species to establish in otherwise competitive environments. The size of and time since disturbance may determine the establishment ability of these species. We investigated gap dynamics of an old-growth red pine (Pinus resinosa Sol. ex Aiton) forest in the Great Lakes–St. Lawrence forest in northern Ontario, Canada, a transition zone between temperate and boreal forest. We investigated the effects of gaps of different sizes and ages on tree species abundance and basal area. Our results show that tree species from the temperate forest further south, such as red maple (Acer rubrum L.), red oak (Quercus rubra L.), and white pine (Pinus strobus L.), establish more often in large, old gaps; however, tree species that have more northern distributions, such as black spruce (Picea mariana Mill.), paper birch (Betula papyrifera Marsh.), and red pine show no difference in establishment ability with gap size or age. These differences in composition could not be attributed to autogenic succession. We conclude that treefall gaps in this forest facilitate the establishment of northward migrating species, potentially providing a pathway for future forest migration in response to recent changes in climate.
    BibTeX:
    @article{leithead_northward_2010,
      author = {Leithead, Mark D. and Anand, Madhur and Silva, Lucas C. R.},
      title = {Northward migrating trees establish in treefall gaps at the northern limit of the temperate–boreal ecotone, Ontario, Canada},
      journal = {Oecologia},
      year = {2010},
      volume = {164},
      number = {4},
      pages = {1095--1106},
      url = {https://link.springer.com/article/10.1007/s00442-010-1769-z},
      doi = {http://doi.org/10.1007/s00442-010-1769-z}
    }
    					
    rossatto_leaf_2010 Rossatto, D.R.; Takahashi, F.S.C.; Silva, L. d.C.R. & Franco, A.C. Leaf functional traits in sun and shade leaves of gallery forest trees in Distrito Federal, Brazil 2010 Acta Botanica Brasilica
    Vol. 24 (3) , pp. 640-647  
    article
    BibTeX:
    @article{rossatto_leaf_2010,
      author = {Rossatto, Davi Rodrigo and Takahashi, Frederico Scherr Caldeira and Silva, Lucas de Carvalho Ramos and Franco, Augusto César},
      title = {Leaf functional traits in sun and shade leaves of gallery forest trees in Distrito Federal, Brazil},
      journal = {Acta Botanica Brasilica},
      year = {2010},
      volume = {24},
      number = {3},
      pages = {640--647},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0102-33062010000300007&lng=en&nrm=iso&tlng=pt},
      doi = {http://doi.org/10.1590/S0102-33062010000300007}
    }
    					
    silva_deciphering_2010 Silva, L.C.R.; Vale, G.D.; Haidar, R.F. & Sternberg, L. d.S.L. Deciphering earth mound origins in central Brazil 2010 Plant and Soil
    Vol. 336 (1-2) , pp. 3-14  
    article
    Abstract: Mound fields are a common landscape throughout the world and much of the evidence for their origin has been of a circumstantial nature. It has been hypothesized that earth mounds emerge over grasslands by termite activity; alternatively, they might be formed after erosion. We tested whether a mound field in central Brazil was generated by termite activity or erosion. We used soil organic matter isotopic composition, soil chemical, physical and floristic composition to determine the origin of a mound field. If the mounds emerged by termite activity in an established grassland the soil organic matter below the mound should have the isotopic signature of C4 dominated grassland, which contrasts with savanna C3 + C4 signature. Additionally, soil traits should resemble those of the grassland. All markers indicate that the mounds were formed by erosion. The soil isotopic composition, chemical traits and texture below the mound resembled those of the savanna and not those of the grassland. Moreover, most of the species present in the mound were typical of savanna. Concrete evidence is provided that mound fields in the studied area were produced by erosion of a savanna ecosystem and not termite activity. The use of the techniques applied here would improve the assessments of whether analogous landscapes are of a biogenic nature or not.
    BibTeX:
    @article{silva_deciphering_2010,
      author = {Silva, Lucas C. R. and Vale, Gabriel D. and Haidar, Ricardo F. and Sternberg, Leonel da S. L.},
      title = {Deciphering earth mound origins in central Brazil},
      journal = {Plant and Soil},
      year = {2010},
      volume = {336},
      number = {1-2},
      pages = {3--14},
      url = {https://link.springer.com/article/10.1007/s11104-010-0329-y},
      doi = {http://doi.org/10.1007/s11104-010-0329-y}
    }
    					
    silva_evolution_2010 Silva, L.C.R. & Corrźa, R.S. Evolution of substrate quality of a mined area in the Brazilian Savanna after revegetation with Stylosanthes spp 2010 Revista Brasileira de Engenharia Agrícola e Ambiental
    Vol. 14 (8) , pp. 835-841  
    article
    BibTeX:
    @article{silva_evolution_2010,
      author = {Silva, Lucas C. R. and Corrźa, Rodrigo S.},
      title = {Evolution of substrate quality of a mined area in the Brazilian Savanna after revegetation with Stylosanthes spp},
      journal = {Revista Brasileira de Engenharia Agrícola e Ambiental},
      year = {2010},
      volume = {14},
      number = {8},
      pages = {835--841},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1415-43662010000800007&lng=en&nrm=iso&tlng=es},
      doi = {http://doi.org/10.1590/S1415-43662010000800007}
    }
    					
    silva_not_2010 Silva, L.C.R.; Haridasan, M.; Sternberg, L.S.L.; Franco, A.C. & Hoffmann, W.A. Not all forests are expanding over central Brazilian savannas 2010 Plant and Soil
    Vol. 333 (1-2) , pp. 431-442  
    article
    Abstract: Recently we reported on the expansion of riparian forests into savannas in central Brazil. To enlarge the scope of the earlier study we investigated whether upland deciduous and xeromorphic forests behaved similarly. We investigated past vegetation changes that occurred in forest/savanna transitions using carbon isotope ratios (δ13C) measured in the soil organic matter as a tracer. We analyzed the 14C activity where δ13C showed major shifts in vegetation. The role of soil chemical and physical attributes in defining vegetation distribution is discussed. Structural changes in vegetation were found to be associated with shifts in the isotope composition (δ13C) of soil organic matter. This was attributed to intrinsic differences in the biomass of trees and grasses and allowed for the determination of past shifts in vegetation by evaluating δ13C at different depths. The deciduous forest decreased in area approximately 980 years ago. Tree cover increased in the xeromorphic forest, but the border stayed stable through time. The deciduous forest and adjacent savanna have eutrophic soils while the xeromorphic forest and adjacent savanna have dystrophic soils. However, greater organic carbon, nitrogen and phosphorus concentrations are observed in the forests. We provide concrete evidence of deciduous forest retreat unlike the stability observed in the xeromorphic forest/savanna boundary. These results contrast with the expansion of riparian forests recently reported in the same region.
    BibTeX:
    @article{silva_not_2010,
      author = {Silva, Lucas C. R. and Haridasan, Mundayatan and Sternberg, Leonel S. L. and Franco, Augusto C. and Hoffmann, William A.},
      title = {Not all forests are expanding over central Brazilian savannas},
      journal = {Plant and Soil},
      year = {2010},
      volume = {333},
      number = {1-2},
      pages = {431--442},
      url = {https://link.springer.com/article/10.1007/s11104-010-0358-6},
      doi = {http://doi.org/10.1007/s11104-010-0358-6}
    }
    					
    silva_recent_2010 Silva, L.C.R.; Anand, M. & Leithead, M.D. Recent Widespread Tree Growth Decline Despite Increasing Atmospheric CO2 2010 PLOS ONE
    Vol. 5 (7) , pp. e11543  
    article carbon dioxide, climate change, forests, latitude, oaks, pines, spruces, trees
    Abstract: Background The synergetic effects of recent rising atmospheric CO2 and temperature are expected to favor tree growth in boreal and temperate forests. However, recent dendrochronological studies have shown site-specific unprecedented growth enhancements or declines. The question of whether either of these trends is caused by changes in the atmosphere remains unanswered because dendrochronology alone has not been able to clarify the physiological basis of such trends. Methodology/Principal Findings Here we combined standard dendrochronological methods with carbon isotopic analysis to investigate whether atmospheric changes enhanced water use efficiency (WUE) and growth of two deciduous and two coniferous tree species along a 9° latitudinal gradient across temperate and boreal forests in Ontario, Canada. Our results show that although trees have had around 53% increases in WUE over the past century, growth decline (measured as a decrease in basal area increment – BAI) has been the prevalent response in recent decades irrespective of species identity and latitude. Since the 1950s, tree BAI was predominantly negatively correlated with warmer climates and/or positively correlated with precipitation, suggesting warming induced water stress. However, where growth declines were not explained by climate, WUE and BAI were linearly and positively correlated, showing that declines are not always attributable to warming induced stress and additional stressors may exist. Conclusions Our results show an unexpected widespread tree growth decline in temperate and boreal forests due to warming induced stress but are also suggestive of additional stressors. Rising atmospheric CO2 levels during the past century resulted in consistent increases in water use efficiency, but this did not prevent growth decline. These findings challenge current predictions of increasing terrestrial carbon stocks under climate change scenarios.
    BibTeX:
    @article{silva_recent_2010,
      author = {Silva, Lucas C. R. and Anand, Madhur and Leithead, Mark D.},
      title = {Recent Widespread Tree Growth Decline Despite Increasing Atmospheric CO2},
      journal = {PLOS ONE},
      year = {2010},
      volume = {5},
      number = {7},
      pages = {e11543},
      url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011543},
      doi = {http://doi.org/10.1371/journal.pone.0011543}
    }
    					
    silva_past_2009 Silva, L.C.R.; Anand, M.; Oliveira, J.M. & Pillar, V.D. Past century changes in Araucaria angustifolia (Bertol.) Kuntze water use efficiency and growth in forest and grassland ecosystems of southern Brazil: implications for forest expansion 2009 Global Change Biology
    Vol. 15 (10) , pp. 2387-2396  
    article araucaria, basal area increment, carbon isotope, climate change, ecotones, forest expansion, grasslands, southern brazil, tree-rings, water use efficiency
    Abstract: Araucaria angustifolia (Bertol.) Kuntze is an indigenous conifer tree restricted to the southern region of South America that plays a key role in the dynamics of regional ecosystems where forest expansion over grasslands has been observed. Here, we evaluate the changes in intrinsic water use efficiency (iWUE) and basal area increment (BAI) of this species in response to atmospheric CO2, temperature and precipitation over the last century. Our investigation is based on tree-rings taken from trees located in forest and grassland sites in southern Brazil. Differences in carbon isotopic composition (δ13C), 13CO2 discrimination (Delta-13C) and intracellular carbon concentration (Ci) are also reported. Our results indicate an age effect on Delta-13C in forest trees during the first decades of growth. This age effect is not linked to an initial BAI suppression, suggesting the previous existence of nonforested vegetation in the forest sites. After maturity all trees show similar temporal trends in carbon isotope-derived variables and increasing iWUE, however, absolute values are significantly different between forest and grassland sites. The iWUE is higher in forest trees, indicating greater water competition or nutritional availability, relative to grassland, or both. BAI is also higher in forest trees, but it is not linked with iWUE or atmospheric CO2. Nevertheless, in both forest and grassland sites A. angustifolia has had growth limitations corresponding to low precipitation and high temperatures observed in the 1940s.
    BibTeX:
    @article{silva_past_2009,
      author = {Silva, Lucas C. R. and Anand, Madhur and Oliveira, Juliano M. and Pillar, Valério D.},
      title = {Past century changes in Araucaria angustifolia (Bertol.) Kuntze water use efficiency and growth in forest and grassland ecosystems of southern Brazil: implications for forest expansion},
      journal = {Global Change Biology},
      year = {2009},
      volume = {15},
      number = {10},
      pages = {2387--2396},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2009.01859.x/abstract},
      doi = {http://doi.org/10.1111/j.1365-2486.2009.01859.x}
    }
    					
    faria_chemical_2008 Faria, J.P.; Almeida, F.; Silva, L.C.R. d.; Vieira, R.F. & Agostini-Costa, T. d.S. Chemical characterization of pulp of Butia capitata var capitata 2008 Revista Brasileira de Fruticultura
    Vol. 30 (3) , pp. 827-829  
    article
    BibTeX:
    @article{faria_chemical_2008,
      author = {Faria, Juliana Pereira and Almeida, Fernanda and Silva, Lucas Carvalho Ramos da and Vieira, Roberto Fontes and Agostini-Costa, TČnia da Silveira},
      title = {Chemical characterization of pulp of Butia capitata var capitata},
      journal = {Revista Brasileira de Fruticultura},
      year = {2008},
      volume = {30},
      number = {3},
      pages = {827--829},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0100-29452008000300045&lng=en&nrm=iso&tlng=es},
      doi = {http://doi.org/10.1590/S0100-29452008000300045}
    }
    					
    faria_chemical_2008-1 Faria, J.P.; Arellano, D.B.; Grimaldi, R.; Silva, L.C.R. d.; Vieira, R.F.; Silva, D.B. d. & Agostini-Costa, T. d.S. Chemical characterization of nut of Butia capitata var capitata 2008 Revista Brasileira de Fruticultura
    Vol. 30 (2) , pp. 549-552  
    article
    BibTeX:
    @article{faria_chemical_2008-1,
      author = {Faria, Juliana Pereira and Arellano, Daniel Barrera and Grimaldi, Renato and Silva, Lucas Carvalho Ramos da and Vieira, Roberto Fontes and Silva, Dijalma Barbosa da and Agostini-Costa, TČnia da Silveira},
      title = {Chemical characterization of nut of Butia capitata var capitata},
      journal = {Revista Brasileira de Fruticultura},
      year = {2008},
      volume = {30},
      number = {2},
      pages = {549--552},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0100-29452008000200049&lng=en&nrm=iso&tlng=pt},
      doi = {http://doi.org/10.1590/S0100-29452008000200049}
    }
    					
    silva_expansion_2008 Silva, L.C.R.; Sternberg, L.; Haridasan, M.; Hoffmann, W.A.; Miralles-Wilhelm, F. & Franco, A.C. Expansion of gallery forests into central Brazilian savannas 2008 Global Change Biology
    Vol. 14 (9) , pp. 2108-2118  
    article carbon isotope ratios, carbon sink, carbon stocks, climate change, gallery forest, leaf area index, nutrients, savanna, tropical ecosystems, vegetation dynamics
    Abstract: Upland tropical forests have expanded and contracted in response to past climates, but it is not clear whether similar dynamics were exhibited by gallery (riparian) forests within savanna biomes. Because such forests generally have access to ample water, their extent may be buffered against changing climates. We tested the long-term stability of gallery forest boundaries by characterizing the border between gallery forests and savannas and tracing the presence of gallery forest through isotopic analysis of organic carbon in the soil profile. We measured leaf area index, grass vs. shrub or tree coverage, the organic carbon, phosphorus, nitrogen and calcium concentrations in soils and the carbon isotope ratios of soil organic matter in two transitions spanning gallery forests and savanna in a Cerrado ecosystem. Gallery forests without grasses typically show a greater leaf area index in contrast to savannas, which show dense grass coverage. Soils of gallery forests have significantly greater concentrations of organic carbon, phosphorus, nitrogen and calcium than those of savannas. Soil organic carbon of savannas is significantly more enriched in 13C compared with that of gallery forests. This difference in enrichment is in part caused by the presence of C4 grasses in savanna ecosystem and its absence in gallery forests. Using the 13C abundance as a signature for savanna and gallery forest ecosystems in 1 m soil cores, we show that the borders of gallery forests have expanded into the savanna and that this process initiated at least 3000–4000 bp based on 14C analysis. Gallery forests, however, may be still expanding as we found more recent transitions according to 14C activity measurements. We discuss the possible mechanisms of gallery forest expansion and the means by which nutrients required for the expansion of gallery forest might accumulate.
    BibTeX:
    @article{silva_expansion_2008,
      author = {Silva, Lucas C. R. and Sternberg, Leonel and Haridasan, Mundayatan and Hoffmann, William A. and Miralles-Wilhelm, Fernando and Franco, Augusto C.},
      title = {Expansion of gallery forests into central Brazilian savannas},
      journal = {Global Change Biology},
      year = {2008},
      volume = {14},
      number = {9},
      pages = {2108--2118},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2008.01637.x/abstract},
      doi = {http://doi.org/10.1111/j.1365-2486.2008.01637.x}
    }
    					
    silva_survival_2008 Silva, L. d.C.R. & Corrźa, R.S. Survival and growth of six tree species under four treatments on a mined areain the Brazilian savanna 2008 Revista Árvore
    Vol. 32 (4) , pp. 731-740  
    article
    BibTeX:
    @article{silva_survival_2008,
      author = {Silva, Lucas de Carvalho Ramos and Corrźa, Rodrigo Studart},
      title = {Survival and growth of six tree species under four treatments on a mined areain the Brazilian savanna},
      journal = {Revista Árvore},
      year = {2008},
      volume = {32},
      number = {4},
      pages = {731--740},
      url = {http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0100-67622008000400015&lng=en&nrm=iso&tlng=pt},
      doi = {http://doi.org/10.1590/S0100-67622008000400015}
    }
    					
    borghetti_aqueous_2005 Borghetti, F.; L.C.R., S.I.L.V.A.; PINHEIRO, J.D.; VARELLA, B.B. & Ferreira, A. Aqueous leaf extract properties of Cerrado species in Central Brazil. 2005   book
    BibTeX:
    @book{borghetti_aqueous_2005,
      author = {Borghetti, Fabian and L.C.R., SILVA and J.D., PINHEIRO and B.B., VARELLA and Ferreira, Alfredo},
      title = {Aqueous leaf extract properties of Cerrado species in Central Brazil.},
      year = {2005}
    }
    					
    Williams2010 Williams, J.W.; Shuman, B.; Bartlein, P.J.; Diffenbaugh, N.S. & Webb, T. Rapid, time-transgressive, and variable responses to early Holocene midcontinental drying in North America 2010 Geology
    Vol. 38 (2) , pp. 135-138  
    article paleoecology and paleoclimatology
    Abstract: The end Pleistocene to early Holocene drying of the North American
    midcontinent is an important case study for understanding regional
    drought, its drivers, and its impacts. This paper synthesizes pollen,
    delta C-13, eolian, and paleohydrological proxies to document the
    spatial and temporal patterns in the onset and rate of drying. The
    timing of onset ranged from 14 to 6 ka with most sites drying between
    10 and 8 ka (calendar years ago). The dominant spatial pattern is
    time transgressive, with interior Great Plains sites beginning to
    dry before peripheral sites. This time-transgressive trend can be
    explained as a region-wide drying that caused ecotones to shift eastward,
    or could indicate a progressive shift in atmospheric drying from
    west to east. One-third of sites responded rapidly to drying; a cluster
    of rapid responses occurred ca. 8 ka. The combination of onsets between
    14 and 6 ka and rapid responses at 8 ka strongly suggests that (1)
    the combination of high summer insolation, Laurentide Ice Sheet retreat,
    and Lake Agassiz drainage drove midcontinental drying, and (2) drying
    accelerated with Laurentide Ice Sheet collapse at 8.4 ka. Local factors
    strongly mediate the timing and rate of site responses to regional
    drying. Local responses to future drying in the Great Plains also
    should be highly variable, which challenges impact assessments of
    future climate changes.
    BibTeX:
    @article{Williams2010,
      author = {Williams, JW and Shuman, B and Bartlein, PJ and Diffenbaugh, NS and Webb, T},
      title = {Rapid, time-transgressive, and variable responses to early Holocene midcontinental drying in North America},
      journal = {Geology},
      year = {2010},
      volume = {38},
      number = {2},
      pages = {135--138}
    }
    					
    Bartlein1998 Bartlein, P.J.; Anderson, K.H.; Anderson, P.M.; Edwards, M.E.; Mock, C.J.; Thompson, R.S.; Webb, R.S. & Whitlock, C. Paleoclimate simulations for North America over the past 21,000 years: Features of the simulated climate and comparisons with paleoenvironmental data 1998 Quaternary Science Reviews
    Vol. 17 (6-7) , pp. 549-585  
    article paleoclimatic analysis and data-model comparisons
    Abstract: Maps of upper-level and surface winds and of surface temperature and
    precipitation illustrate the results of a sequence of global paleoclimatic
    simulations spanning the past 21,000 yr for North America. We review
    (a) the large-scale features of circulation, temperature, and precipitation
    that appear in the simulations from the NCAR Community Climate Model
    Version 1 (CCM 1), (b) the implications of the simulated climate
    for the past continental-scale distributions of three plant taxa
    (Picea spp., Pseudotsuga menziesii. and Artemisia tridentata), which
    are broadly representative of the vegetation across the continent,
    and (c) the potential explanations in terms of atmospheric circulation
    or surface energy- and water-balance processes for mismatches between
    the simulations and observations. Most Of the broad-scale features
    of previous paleoclimatic simulations with the NCAR CCM 0 for North
    America are present in the current simulations. Many of the elements
    of a conceptual model (based on previous climate simulations) that
    describes the controls of paleoclimatic variations across North America
    during the past 21,000 yr are found in simulations reviewed here.
    These include (1) displacement of the jet stream by the Laurentide
    Ice Sheet to the south of its present position in both winter and
    summer, (2) generation of a 'glacial anticyclone' over the ice sheet
    at the LGM, and the consequent induction of large-scale sinking motions
    induced over eastern North America, (3) changes in the strength of
    surface atmospheric circulation features through time, including
    weakening of the Aleutian low in winter, and strengthening of the
    eastern Pacific and Bermuda high-pressure systems in summer as the
    ice sheet decreased in size, (4) development of a 'heat low' at the
    surface and a strengthened ridge in the upper-atmosphere over the
    continent at the time of the maximum summer insolation anomaly, (5)
    increases in summer temperature earlier in regions remote from the
    ice sheet (these increases appear earlier in the present (CCM 1)
    simulations than in the previous (CCM 0) ones, however), and (6)
    continuation of negative winter temperature anomalies into the middle
    Holocene. Ln general, simulated surface conditions that are discordant
    with paleoenvironmental observations can be attributed to the simulation
    of particular atmospheric circulation patterns (e.g. those that suppress
    precipitation or advect warm air into a region), with these mismatches
    amplified in Beringia and the southeastern United States by surface
    energy- and water-balance processes. (C) 1998 Elsevier Science Ltd.
    All rights reserved.
    BibTeX:
    @article{Bartlein1998,
      author = {Bartlein, PJ and Anderson, KH and Anderson, PM and Edwards, ME and Mock, CJ and Thompson, RS and Webb, RS and Whitlock, C},
      title = {Paleoclimate simulations for North America over the past 21,000 years: Features of the simulated climate and comparisons with paleoenvironmental data},
      journal = {Quaternary Science Reviews},
      year = {1998},
      volume = {17},
      number = {6-7},
      pages = {549--585},
      note = {http://geography.uoregon.edu/envchange/figures/Bartlein-etal-QSR-1998-figs/index.html}
    }
    					
    Retallack1988 Retallack, G. & McDowell, P. Penrose conference report - paleoenvironmental interpretation of paleosols 1988 Geology
    Vol. 16 (4) , pp. 375-376  
    article
    BibTeX:
    @article{Retallack1988,
      author = {Retallack, G and McDowell, P},
      title = {Penrose conference report - paleoenvironmental interpretation of paleosols},
      journal = {Geology},
      year = {1988},
      volume = {16},
      number = {4},
      pages = {375--376}
    }
    					
    RetallackGavinDavisEtAl2016 Retallack, G.J.; Gavin, D.G.; Davis, E.B.; Sheldon, N.D.; Erlandson, J.M.; Reed, M.H.; Bestland, E.A.; Roering, J.J.; Carson, R.J. & Mitchell, R.B. Oregon 2100: Projected Climatic and Ecological Changes 2016 Bulletin of the Museum of Natural History, University of Oregon (26) , pp. 1-21   article
    BibTeX:
    @article{RetallackGavinDavisEtAl2016,
      author = {Retallack, Gregory J. and Gavin, Daniel G. and Davis, Edward Byrd and Sheldon, Nathan D. and Erlandson, Jon M. and Reed, Mark H. and Bestland, Erick A. and Roering, Joshua J. and Carson, Robert J. and Mitchell, Ronald B.},
      title = {Oregon 2100: Projected Climatic and Ecological Changes},
      journal = {Bulletin of the Museum of Natural History, University of Oregon},
      year = {2016},
      number = {26},
      pages = {1--21},
      url = {http://journals.oregondigital.org/index.php/nat_history/article/view/3631}
    }
    					
    Bartlein2015 Bartlein, P. Diagnosing Mismatches between Simulations and Observations in Data-Model Comparisons using the CMIP5/PMIP3 Simulations 2015   inproceedings
    BibTeX:
    @inproceedings{Bartlein2015,
      author = {Bartlein, Patrick},
      title = {Diagnosing Mismatches between Simulations and Observations in Data-Model Comparisons using the CMIP5/PMIP3 Simulations},
      publisher = {Agu},
      year = {2015},
      url = {https://agu.confex.com/agu/fm15/webprogram/Paper76980.html}
    }
    					
    BartleinEdwardsHostetlerEtAl2015 Bartlein, P.J.; Edwards, M.E.; Hostetler, S.W.; Shafer, S.L.; Anderson, P.M.; Brubaker, L.B. & Lozhkin, A.V. Early-Holocene warming in Beringia and its mediation by sea-level and vegetation changes 2015 Climate of the Past
    Vol. 11 (9) , pp. 1197-1222  
    article
    BibTeX:
    @article{BartleinEdwardsHostetlerEtAl2015,
      author = {Bartlein, P. J. and Edwards, M. E. and Hostetler, Steven W. and Shafer, S. L. and Anderson, P. M. and Brubaker, L. B. and Lozhkin, A. V.},
      title = {Early-Holocene warming in Beringia and its mediation by sea-level and vegetation changes},
      journal = {Climate of the Past},
      year = {2015},
      volume = {11},
      number = {9},
      pages = {1197--1222},
      url = {http://www.clim-past.net/11/1197/2015/cp-11-1197-2015.html}
    }
    					
    BosloughNicollDaultonEtAl2015 Boslough, M.; Nicoll, K.; Daulton, T.L.; Scott, A.C.; Claeys, P.; Gill, J.L.; Marlon, J.R. & Bartlein, P.J. Incomplete Bayesian model rejects contradictory radiocarbon data for being contradictory 2015 Proceedings of the National Academy of Sciences
    Vol. 112 (49) , pp. E6722-E6722  
    article
    BibTeX:
    @article{BosloughNicollDaultonEtAl2015,
      author = {Boslough, Mark and Nicoll, Kathleen and Daulton, Tyrone L. and Scott, Andrew C. and Claeys, Philippe and Gill, Jacquelyn L. and Marlon, Jennifer R. and Bartlein, Patrick J.},
      title = {Incomplete Bayesian model rejects contradictory radiocarbon data for being contradictory},
      journal = {Proceedings of the National Academy of Sciences},
      year = {2015},
      volume = {112},
      number = {49},
      pages = {E6722--E6722},
      url = {http://www.pnas.org/content/112/49/E6722},
      doi = {http://doi.org/10.1073/pnas.1519917112}
    }
    					
    DobrowskiSwansonAbatzoglouEtAl2015 Dobrowski, S.Z.; Swanson, A.K.; Abatzoglou, J.T.; Holden, Z.A.; Safford, H.D.; Schwartz, M.K. & Gavin, D.G. Forest structure and species traits mediate projected recruitment declines in western US tree species 2015 Global Ecology and Biogeography
    Vol. 24 , pp. 917-927  
    article climate change, demographic niche differences, facilitation, tree regeneration, water balance, western usa
    Abstract: Aim

    Determine if differences in the climatic niche between conspecific adult and juvenile trees of the western Unites States vary by species traits and to assess if forest canopies moderate the sensitivity of juvenile trees to climatic variation.

    Location

    The western Unites States.

    Methods

    Using data from the USDA Forest Inventory and Analysis programme, we compare the distribution of conspecific adult and juvenile trees for 62 western US tree species. We relate demographic niche differences to species traits including shade and drought tolerance. We model recruitment under projected climate change using generalized linear mixed models, probabilistic uncertainty accounting, forest structural data and projected changes in the climatic water balance.

    Results

    On average juveniles of western US tree species occupy a climatic subset of their conspecific adults. Demographic niche differences increase as species shade and drought tolerance increase and are greatest at climatic range margins, indicating the potential for range contractions. Models calibrated solely with climate data project recruitment declines for 2080 that are 47% larger on average than models that also account for forest structure.

    Main conclusions

    Climate change-driven declines in recruitment in western US tree species may be partly offset by the moderating effect of forest canopies. The importance of this stabilizing process will depend on whether a given site is disturbed and the traits of resident species, including their ability to utilize sites that have buffered microclimates. Conversely, our results suggest that broad-scale disturbances which result in the loss of forest canopy will amplify the effects of climate change on tree recruitment.

    BibTeX:
    @article{DobrowskiSwansonAbatzoglouEtAl2015,
      author = {Dobrowski, Solomon Z. and Swanson, Alan K. and Abatzoglou, John T. and Holden, Zachary A. and Safford, Hugh D. and Schwartz, Mike K. and Gavin, Daniel G.},
      title = {Forest structure and species traits mediate projected recruitment declines in western US tree species},
      journal = {Global Ecology and Biogeography},
      year = {2015},
      volume = {24},
      pages = {917--927},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/geb.12302/abstract},
      doi = {http://doi.org/10.1111/geb.12302}
    }
    					
    Gavin2015 Gavin, D.G. Vegetation stability and the habitat associations of the endemic taxa of the Olympic Peninsula, Washington, USA 2015 Frontiers of Biogeography
    Vol. 7 (2) , pp. 38-51  
    article
    Abstract: Explanations for areas of endemism often involve relative climatic stability, or low climate velocity, over time scales ranging from the Pleistocene to the late Cenozoic. Given that many narrowly endemic taxa in forested landscapes display discrete habitat associations, habitat stability should be similarly important for endemic persistence. Furthermore, while past climate variability is exceedingly difficult to quantify on millennial time scales, past distributions of habitats may be robustly inferred from paleoecological records. The Olympic Peninsula, Washington, supports a biota with several insular features including 29 endemic plant and animal taxa. Here I present the geographic distribution and habitat of the endemic taxa, and then examine the vegetation stability of the past 14,300 years from five pollen records associated with discrete vegetation zones on the peninsula. I show that 11 endemics have distributions centered on dry alpine scree and rock in the northeastern quadrant of the peninsula, and nine occur in shaded riparian forests in the southwest. Vegetation turnover during the post-glacial period was smallest in these areas. However, another long pollen record from the western peninsula reveals existence of shrub tundra and greatly reduced forest cover, indicating southward displacement of shaded riparian habitats by perhaps as much as 100 km. Although this study supports an association of post-glacial vegetation stability with endemism, records spanning the glacial maximum indicate widespread tundra during long periods of the late Pleistocene and therefore suggest southern displacement of forest-associated endemics. While some of the alpine scree-associated endemics may have persisted in situ, many others likely arrived via a variety of dispersal trajectories. These histories include dispersal from southern refugia towards ocean barriers preventing further northward dispersal, contraction from more widespread distributions, and recent divergence from sister taxa. This study shows that paleoecological records can cast strong doubt on the inference that areas of endemism necessarily imply in situ glacial survival.
    BibTeX:
    @article{Gavin2015,
      author = {Gavin, Daniel G.},
      title = {Vegetation stability and the habitat associations of the endemic taxa of the Olympic Peninsula, Washington, USA},
      journal = {Frontiers of Biogeography},
      year = {2015},
      volume = {7},
      number = {2},
      pages = {38--51},
      url = {http://escholarship.org/uc/item/3dk4069j}
    }
    					
    Gavin2015a Gavin, D. Watershed erosion estimated from a high-resolution sediment core reveals a non-stationary frequency-magnitude relationship and importance of seasonal climate drivers 2015   inproceedings
    BibTeX:
    @inproceedings{Gavin2015a,
      author = {Gavin, Daniel},
      title = {Watershed erosion estimated from a high-resolution sediment core reveals a non-stationary frequency-magnitude relationship and importance of seasonal climate drivers},
      publisher = {Agu},
      year = {2015},
      url = {https://agu.confex.com/agu/fm15/webprogram/Paper68097.html}
    }
    					
    GavinBrubaker2015 Gavin, D.G. & Brubaker, L.B. Late Pleistocene and Holocene Environmental Change on the Olympic Peninsula, Washington 2015 (222)   book biogeosciences, climate change, environmental geography, fire history, landscape ecology, natural disturbances, olympic peninsula, phytogeography, plant ecology, snowpack, stream flow, temperate rainforest
    Abstract: The natural environment of the Olympic Peninsula is reviewed with an emphasis on climatic gradients and associated patterns in forest communities and natural disturbance regimes. The regional climate is described with respect to the broadscale circulation features and locally important topographic effects. Analyses of weather station data reveal important trends in temperature, while snow survey and glacier monitoring reveal decades-long decline in snowpack. The summer streamflow of unregulated rivers is shown to have a strong link to variation in snowpack. The seven major vegetation zones of the peninsula are described and controls of species abundance among vegetation zones are discussed with respect to species traits and climatic gradients. The natural disturbance regimes of the peninsula are summarized. Fire history data from tree-ring records and fire regime statistics from historical records reveal the pronounced gradient of fire across the peninsula and the episodic pattern of large fire events. Wind, insect, geomorphic, and intense herbivory are also briefly reviewed.
    BibTeX:
    @book{GavinBrubaker2015,
      author = {Gavin, Daniel G. and Brubaker, Linda B.},
      title = {Late Pleistocene and Holocene Environmental Change on the Olympic Peninsula, Washington},
      publisher = {Springer International Publishing},
      year = {2015},
      number = {222},
      url = {http://link.springer.com/chapter/10.1007/978-3-319-11014-1_1}
    }
    					
    HarrisonBartleinIzumiEtAl2015 Harrison, S.P.; Bartlein, P.J.; Izumi, K.; Li, G.; Annan, J.; Hargreaves, J.; Braconnot, P. & Kageyama, M. Evaluation of CMIP5 palaeo-simulations to improve climate projections 2015 Nature Climate Change
    Vol. 5 (8) , pp. 735-743  
    article
    BibTeX:
    @article{HarrisonBartleinIzumiEtAl2015,
      author = {Harrison, S. P. and Bartlein, P. J. and Izumi, K. and Li, G. and Annan, J. and Hargreaves, J. and Braconnot, P. and Kageyama, M.},
      title = {Evaluation of CMIP5 palaeo-simulations to improve climate projections},
      journal = {Nature Climate Change},
      year = {2015},
      volume = {5},
      number = {8},
      pages = {735--743},
      url = {http://www.nature.com/nclimate/journal/v5/n8/full/nclimate2649.html}
    }
    					
    HerringGavin2015 Herring, E.M. & Gavin, D.G. Climate and vegetation since the Last Interglacial (MIS 5e) in a putative glacial refugium, northern Idaho, USA 2015 Quaternary Science Reviews
    Vol. 117 , pp. 82-95  
    article last interglacial, paleoecology, pollen, quaternary, refugium
    Abstract: There are very few terrestrial sediment records from North America that contain a nearly continuous sequence spanning from the Last Interglacial period to the present. We present stratigraphic records of pollen and several other proxies from a Carex-dominated wetland, Star Meadows, located 140 km south of the maximum extent of the Cordilleran Ice Sheet and near the current southern extent of interior mesic forests in northern Idaho. Many species in this region are disjunct by 160 km of arid steppe and dry forest from their more extensive distribution along the Pacific Northwest coast and may have survived in an interior refugium. The chronology for the upper 251 cm was determined by six radiocarbon dates and one tephra deposit, and the age of the remainder of the core (251–809 cm) was estimated by correlation with SPECMAP d18O. Fluctuating water levels were inferred from alternating peat, biogenic silica, and aquatic pollen types. During MIS 5e the region was warmer and drier than today and was dominated by Pinus (likely Pinus contorta) mixed conifer forest surrounding a Carex meadow. A cool-moist climate (MIS 5b–5d) soon developed, and the site was inundated with deep water. Pollen indicated wetland vegetation (Betula glandulosa, Typhaceae, and Salix) developed around a lake with a Pseudotsuga/Larix and Picea forest on the surrounding slopes. During MIS 5a, a warmer climate supported a Pseudotsuga/Larix, Abies, and Picea forest on the surrounding hillsides and a Carex-dominated environment within a dry meadow. From MIS 4 to MIS 3, a cool and wet Pinus and Picea forest predominated. Water levels rose, enabling Nuphar to persist within a perennial lake while a sedge fen established along the lake margin. As climate transitioned into MIS 2, a cooler and drier climate supported a Pinus and Picea subalpine parkland, though water levels remained high enough to support Nuphar. During the Last Glacial Maximum the sediment was mainly silt and clay with high Artemisia and very poor pollen preservation. Glaciers descended to 500 m elevation above Star Meadows in adjacent drainages suggesting a periglacial environment occurred at the site. Lake level decreased through the Pleistocene–Holocene transition (ca. 11.7 ka) and the site returned to a sedge peatland surrounded by an open Pinus forest. The most striking vegetation change occurred in the middle to late Holocene with the first occurrence and then later dominance of Cupressaceae pollen, most likely Thuja plicata, which is a dominant species in modern interior mesic forests. The late Holocene vegetation was uniquely mesic in the context of the last 120,000 years, casting doubt on this region serving as a glacial refugium.
    BibTeX:
    @article{HerringGavin2015,
      author = {Herring, Erin M. and Gavin, Daniel G.},
      title = {Climate and vegetation since the Last Interglacial (MIS 5e) in a putative glacial refugium, northern Idaho, USA},
      journal = {Quaternary Science Reviews},
      year = {2015},
      volume = {117},
      pages = {82--95},
      url = {http://www.sciencedirect.com/science/article/pii/S0277379115001353},
      doi = {http://doi.org/10.1016/j.quascirev.2015.03.028}
    }
    					
    IzumiBartleinHarrison2015 Izumi, K.; Bartlein, P. & Harrison, S. Paleoclimate diagnostics: consistent large-scale temperature responses in warm and cold climates 2015
    Vol. 17 EGU General Assembly Conference Abstracts , pp. 3262  
    inproceedings
    BibTeX:
    @inproceedings{IzumiBartleinHarrison2015,
      author = {Izumi, Kenji and Bartlein, Patrick and Harrison, Sandy},
      title = {Paleoclimate diagnostics: consistent large-scale temperature responses in warm and cold climates},
      booktitle = {EGU General Assembly Conference Abstracts},
      year = {2015},
      volume = {17},
      pages = {3262},
      url = {http://adsabs.harvard.edu/abs/2015EGUGA..17.3262I}
    }
    					
    KranabetterMcLauchlanEndersEtAl2015 Kranabetter, J.M.; McLauchlan, K.K.; Enders, S.K.; Fraterrigo, J.M.; Higuera, P.E.; Morris, J.L.; Rastetter, E.B.; Barnes, R.; Buma, B.; Gavin, D.G.; Gerhart, L.M.; Gillson, L.; Hietz, P.; Mack, M.C.; McNeil, B. & Perakis, S. A framework to assess biogeochemical response to ecosystem disturbance using nutrient partitioning ratios 2015 Ecosystems
    Vol. 19 , pp. 387-395  
    article disturbance, ecology, environmental management, fire regime, geoecology/natural processes, hydrology/water resources, multiple element limitation (mel) model, nitrogen stocks, nutrient ratio, plant sciences, succession, zoology
    Abstract: Disturbances affect almost all terrestrial ecosystems, but it has been difficult to identify general principles regarding these influences. To improve our understanding of the long-term consequences of disturbance on terrestrial ecosystems, we present a conceptual framework that analyzes disturbances by their biogeochemical impacts. We posit that the ratio of soil and plant nutrient stocks in mature ecosystems represents a characteristic site property. Focusing on nitrogen (N), we hypothesize that this partitioning ratio (soil N: plant N) will undergo a predictable trajectory after disturbance. We investigate the nature of this partitioning ratio with three approaches: (1) nutrient stock data from forested ecosystems in North America, (2) a process-based ecosystem model, and (3) conceptual shifts in site nutrient availability with altered disturbance frequency. Partitioning ratios could be applied to a variety of ecosystems and successional states, allowing for improved temporal scaling of disturbance events. The generally short-term empirical evidence for recovery trajectories of nutrient stocks and partitioning ratios suggests two areas for future research. First, we need to recognize and quantify how disturbance effects can be accreting or depleting, depending on whether their net effect is to increase or decrease ecosystem nutrient stocks. Second, we need to test how altered disturbance frequencies from the present state may be constructive or destructive in their effects on biogeochemical cycling and nutrient availability. Long-term studies, with repeated sampling of soils and vegetation, will be essential in further developing this framework of biogeochemical response to disturbance.
    BibTeX:
    @article{KranabetterMcLauchlanEndersEtAl2015,
      author = {Kranabetter, J. Marty and McLauchlan, Kendra K. and Enders, Sara K. and Fraterrigo, Jennifer M. and Higuera, Philip E. and Morris, Jesse L. and Rastetter, Edward B. and Barnes, Rebecca and Buma, Brian and Gavin, Daniel G. and Gerhart, Laci M. and Gillson, Lindsey and Hietz, Peter and Mack, Michelle C. and McNeil, Brenden and Perakis, Steven},
      title = {A framework to assess biogeochemical response to ecosystem disturbance using nutrient partitioning ratios},
      journal = {Ecosystems},
      year = {2015},
      volume = {19},
      pages = {387--395},
      url = {http://link.springer.com/article/10.1007/s10021-015-9934-1},
      doi = {http://doi.org/10.1007/s10021-015-9934-1}
    }
    					
    MarlonKellyDaniauEtAl2015 Marlon, J.R.; Kelly, R.; Daniau, A.-L.; VanniŹre, B.; Power, M.J.; Bartlein, P.; Higuera, P.; Blarquez, O.; Brewer, S.; Brücher, T.; Feurdean, A.; Gil-Romera, G.; Iglesias, V.; Maezumi, S.Y.; Magi, B.; Mustaphi, C.J.C. & Zhihai, T. Reconstructions of biomass burning from sediment charcoal records to improve data-model comparisons 2015 Biogeosciences Discussions
    Vol. 12 (22) , pp. 18571-18623  
    article
    BibTeX:
    @article{MarlonKellyDaniauEtAl2015,
      author = {Marlon, J. R. and Kelly, R. and Daniau, A.-L. and VanniŹre, B. and Power, M. J. and Bartlein, P. and Higuera, P. and Blarquez, O. and Brewer, S. and Brücher, T. and Feurdean, A. and Gil-Romera, G. and Iglesias, V. and Maezumi, S. Y. and Magi, B. and Mustaphi, C. J. C. and Zhihai, T.},
      title = {Reconstructions of biomass burning from sediment charcoal records to improve data-model comparisons},
      journal = {Biogeosciences Discussions},
      year = {2015},
      volume = {12},
      number = {22},
      pages = {18571--18623},
      url = {http://www.biogeosciences-discuss.net/12/18571/2015/},
      doi = {http://doi.org/10.5194/bgd-12-18571-2015}
    }
    					
    MarshallRoeringBartleinEtAl2015 Marshall, J.A.; Roering, J.J.; Bartlein, P.J.; Gavin, D.G.; Granger, D.E.; Rempel, A.W.; Praskievicz, S.J. & Hales, T.C. Frost for the trees: Did climate increase erosion in unglaciated landscapes during the late Pleistocene? 2015 Science Advances
    Vol. 1 (10) , pp. e1500715  
    article
    Abstract: Understanding climatic influences on the rates and mechanisms of landscape erosion is an unresolved problem in Earth science that is important for quantifying soil formation rates, sediment and solute fluxes to oceans, and atmospheric CO2 regulation by silicate weathering. Glaciated landscapes record the erosional legacy of glacial intervals through moraine deposits and U-shaped valleys, whereas more widespread unglaciated hillslopes and rivers lack obvious climate signatures, hampering mechanistic theory for how climate sets fluxes and form. Today, periglacial processes in high-elevation settings promote vigorous bedrock-to-regolith conversion and regolith transport, but the extent to which frost processes shaped vast swaths of low- to moderate-elevation terrain during past climate regimes is not well established. By combining a mechanistic frost weathering model with a regional Last Glacial Maximum (LGM) climate reconstruction derived from a paleo-Earth System Model, paleovegetation data, and a paleoerosion archive, we propose that frost-driven sediment production was pervasive during the LGM in our unglaciated Pacific Northwest study site, coincident with a 2.5 times increase in erosion relative to modern rates. Our findings provide a novel framework to quantify how climate modulates sediment production over glacial-interglacial cycles in mid-latitude unglaciated terrain.
    Frost processes more than doubled erosion rates in unglaciated terrain during the Last Glacial Maximum.
    Frost processes more than doubled erosion rates in unglaciated terrain during the Last Glacial Maximum.
    BibTeX:
    @article{MarshallRoeringBartleinEtAl2015,
      author = {Marshall, Jill A. and Roering, Joshua J. and Bartlein, Patrick J. and Gavin, Daniel G. and Granger, Darryl E. and Rempel, Alan W. and Praskievicz, Sarah J. and Hales, Tristram C.},
      title = {Frost for the trees: Did climate increase erosion in unglaciated landscapes during the late Pleistocene?},
      journal = {Science Advances},
      year = {2015},
      volume = {1},
      number = {10},
      pages = {e1500715},
      url = {http://advances.sciencemag.org/content/1/10/e1500715},
      doi = {http://doi.org/10.1126/sciadv.1500715}
    }
    					
    ShaferBartleinGrayEtAl2015 Shafer, S.L.; Bartlein, P.J.; Gray, E.M. & Pelltier, R.T. Projected Future Vegetation Changes for the Northwest United States and Southwest Canada at a Fine Spatial Resolution Using a Dynamic Global Vegetation Model 2015 PLOS ONE
    Vol. 10 (10) , pp. e0138759  
    article climate change, ecosystems, forests, grasses, paleoclimatology, shrubs, simulation and modeling, trees
    Abstract: Future climate change may significantly alter the distributions of many plant taxa. The effects of climate change may be particularly large in mountainous regions where climate can vary significantly with elevation. Understanding potential future vegetation changes in these regions requires methods that can resolve vegetation responses to climate change at fine spatial resolutions. We used LPJ, a dynamic global vegetation model, to assess potential future vegetation changes for a large topographically complex area of the northwest United States and southwest Canada (38.0–58.0°N latitude by 136.6–103.0°W longitude). LPJ is a process-based vegetation model that mechanistically simulates the effect of changing climate and atmospheric CO 2 concentrations on vegetation. It was developed and has been mostly applied at spatial resolutions of 10-minutes or coarser. In this study, we used LPJ at a 30-second (˜1-km) spatial resolution to simulate potential vegetation changes for 2070–2099. LPJ was run using downscaled future climate simulations from five coupled atmosphere-ocean general circulation models (CCSM3, CGCM3.1(T47), GISS-ER, MIROC3.2(medres), UKMO-HadCM3) produced using the A2 greenhouse gases emissions scenario. Under projected future climate and atmospheric CO 2 concentrations, the simulated vegetation changes result in the contraction of alpine, shrub-steppe, and xeric shrub vegetation across the study area and the expansion of woodland and forest vegetation. Large areas of maritime cool forest and cold forest are simulated to persist under projected future conditions. The fine spatial-scale vegetation simulations resolve patterns of vegetation change that are not visible at coarser resolutions and these fine-scale patterns are particularly important for understanding potential future vegetation changes in topographically complex areas.
    BibTeX:
    @article{ShaferBartleinGrayEtAl2015,
      author = {Shafer, Sarah L. and Bartlein, Patrick J. and Gray, Elizabeth M. and Pelltier, Richard T.},
      title = {Projected Future Vegetation Changes for the Northwest United States and Southwest Canada at a Fine Spatial Resolution Using a Dynamic Global Vegetation Model},
      journal = {PLOS ONE},
      year = {2015},
      volume = {10},
      number = {10},
      pages = {e0138759},
      url = {http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0138759},
      doi = {http://doi.org/10.1371/journal.pone.0138759}
    }
    					
    WalshMarlonGoringEtAl2015 Walsh, M.K.; Marlon, J.R.; Goring, S.J.; Brown, K.J. & Gavin, D.G. A regional perspective on Holocene fire–climate–human interactions in the Pacific Northwest of North America 2015 Annals of the Association of American Geographers
    Vol. 105 (6) , pp. 1135-1157  
    article
    Abstract: Wildfire plays an important role in ecosystems of the Pacific Northwest, but past relationships among fire, climate, and human actions remain unclear. A multiscale analysis of thirty-four macroscopic charcoal records from a variety of biophysical settings was conducted to reconstruct fire activity for the Pacific Northwest (PNW) during the past 12,000 years. Trends in biomass burning and fire frequency are compared to paleoenvironmental and population data at a variety of temporal and spatial scales to better understand fire regime variability on centennial- to millennial-length time scales. PNW fire activity in the early Holocene is linked to climatic and vegetation changes; however, increased fire activity in the middle to late Holocene is inconsistent with long-term trends in temperature and precipitation. Two hypotheses are explored to explain the rise in fire activity after ca. 5,500 calendar years before present, including greater climate variability and increased human use of fire. Climatic changes such as increased El NiĖo/Southern Oscillation event frequency during the past approximately 6,000 years could have led to hydrologic shifts conducive to more frequent fire events, despite overall trends toward cooler and moister conditions. Alternatively, increasing human populations and their associated uses of fire might have increased biomass burning. Centennial-scale changes in fire activity, such as during the Medieval Climate Anomaly and the Little Ice Age, closely match widespread shifts in both climate and population, suggesting that one or both influenced the late-Holocene fire history of the PNW.
    BibTeX:
    @article{WalshMarlonGoringEtAl2015,
      author = {Walsh, Megan K. and Marlon, Jennifer R. and Goring, Simon J. and Brown, Kendrick J. and Gavin, Daniel G.},
      title = {A regional perspective on Holocene fire–climate–human interactions in the Pacific Northwest of North America},
      journal = {Annals of the Association of American Geographers},
      year = {2015},
      volume = {105},
      number = {6},
      pages = {1135--1157},
      url = {http://dx.doi.org/10.1080/00045608.2015.1064457},
      doi = {http://doi.org/10.1080/00045608.2015.1064457}
    }
    					
    Blarquez2014 Blarquez, O.; Vannière, B.; Marlon, J.R.; Daniau, A.-L.; Power, M.J.; Brewer, S. & Bartlein, P.J. paleofire: An R package to analyse sedimentary charcoal records from the Global Charcoal Database to reconstruct past biomass burning 2014 Computers & Geosciences
    Vol. 72 , pp. 255-261  
    article biomass burning, charcoal, databases, fire, r statistical language
    Abstract: We describe a new R package, paleofire, for analysis and synthesis
    of charcoal time series, such as those contained in the Global Charcoal
    Database (GCD), that are used to reconstruct paleofire activity
    (past biomass burning). paleofire is an initiative of the Global
    Paleofire Working Group core team (www.gpwg.org), whose aim is to
    encourage the use of sedimentary charcoal series to develop regional-to-global
    syntheses of paleofire activity, and to enhance access to the GCD
    data by providing a common research framework. Currently, paleofire
    features are organized into three different parts related to (i)
    site selection and charcoal series extraction from the GCD; (ii)
    charcoal data transformation; and (iii) charcoal series compositing
    and synthesis. We provide a technical description of paleofire and
    describe some new implementations such as the circular block bootstrap
    procedure. We tested the software using GCDv3 data from eastern
    North America, and provide examples of interpreting results of regional
    and global syntheses.
    BibTeX:
    @article{Blarquez2014,
      author = {Blarquez, Olivier and Vannière, Boris and Marlon, Jennifer R. and Daniau, Anne-Laure and Power, Mitchell J. and Brewer, Simon and Bartlein, Patrick J.},
      title = {paleofire: An R package to analyse sedimentary charcoal records from the Global Charcoal Database to reconstruct past biomass burning},
      journal = {Computers & Geosciences},
      year = {2014},
      volume = {72},
      pages = {255--261},
      url = {http://www.sciencedirect.com/science/article/pii/S0098300414001861},
      doi = {http://doi.org/10.1016/j.cageo.2014.07.020}
    }
    					
    Cohn2014 Cohn, G.M.; Parsons, R.A.; Heyerdahl, E.K.; Gavin, D.G. & Flower, A. Simulated western spruce budworm defoliation reduces torching and crowning potential: a sensitivity analysis using a physics-based fire model 2014 International Journal of Wildland Fire
    Vol. 23 (5) , pp. 709-720  
    article boreal forest, british-columbia, canopy bulk density, cfd, computational fluid dynamic model, coniferous forests, critical surface fire intensity, douglas-fir, fire behaviour, forest-fire, fuel moisture, lodgepole pine, mountain pine, north-america, outbreaks, surface fire intensity, tree-ring reconstruction, united-states, wfds, wildland-urban interface fire dynamic simulator
    Abstract: The widespread, native defoliator western spruce budworm (Choristoneura
    occidentalis Freeman) reduces canopy fuels, which might affect the
    potential for surface fires to torch (ignite the crowns of individual
    trees) or crown (spread between tree crowns). However, the effects
    of defoliation on fire behaviour are poorly understood. We used a
    physics-based fire model to examine the effects of defoliation and
    three aspects of how the phenomenon is represented in the model (the
    spatial distribution of defoliation within tree crowns, potential
    branchwood drying and model resolution). Our simulations suggest
    that fire intensity and crowning are reduced with increasing defoliation
    compared with un-defoliated trees, regardless of within-crown fuel
    density, but torching is only reduced with decreasing crown fuel
    density. A greater surface fire intensity was required to ignite
    the crown of a defoliated compared with an un-defoliated tree of
    the same crown base height. The effects of defoliation were somewhat
    mitigated by canopy fuel heterogeneity and potential branchwood drying,
    but these effects, as well as computational cell size, were less
    pronounced than the effect of defoliation itself on fire intensity.
    Our study suggests that areas heavily defoliated by western spruce
    budworm may inhibit the spread of crown fires and promote non-lethal
    surface fires.
    BibTeX:
    @article{Cohn2014,
      author = {Cohn, Gregory M. and Parsons, Russell A. and Heyerdahl, Emily K. and Gavin, Daniel G. and Flower, Aquila},
      title = {Simulated western spruce budworm defoliation reduces torching and crowning potential: a sensitivity analysis using a physics-based fire model},
      journal = {International Journal of Wildland Fire},
      year = {2014},
      volume = {23},
      number = {5},
      pages = {709--720},
      doi = {http://doi.org/10.1071/WF13074}
    }
    					
    Flower2014 Flower, A.; Gavin, D.G.; Heyerdahl, E.K.; Parsons, R.A. & Cohn, G.M. Western spruce budworm outbreaks did not increase fire risk over the last three centuries: A dendrochronological analysis of inter-disturbance synergism 2014 PLOS One
    Vol. in press  
    article
    BibTeX:
    @article{Flower2014,
      author = {Flower, Aquila and Gavin, D.G. and Heyerdahl, Emily K. and Parsons, Russell A. and Cohn, Gregory M.},
      title = {Western spruce budworm outbreaks did not increase fire risk over the last three centuries: A dendrochronological analysis of inter-disturbance synergism},
      journal = {PLOS One},
      year = {2014},
      volume = {in press}
    }
    					
    Flower2014a Flower, A.; Gavin, D.G.; Heyerdahl, E.K.; Parsons, R.A. & Cohn, G.M. Drought-triggered western spruce budworm outbreaks in the interior Pacific Northwest: A multi-century dendrochronological record 2014 Forest Ecology and Management
    Vol. 324 , pp. 16-27  
    article defoliators, dendrochronology, drought, insect outbreaks, pacific northwest, western spruce budworm
    Abstract: Douglas-fir forests in the interior Pacific Northwest are subject
    to sporadic outbreaks of the western spruce budworm, a species widely
    recognized as the most destructive defoliator in western North America.
    Outbreaks of the western spruce budworm often occur synchronously
    over broad regions and lead to widespread loss of leaf area and decrease
    in growth rates in affected stands. In spite of the ecological and
    economic significance of this defoliator, the mechanisms controlling
    this species’ population dynamics are still not fully understood.
    We used dendrochronological methods to reconstruct three centuries
    of western spruce budworm outbreaks at thirteen sites along a transect
    running from central Oregon to western Montana and compared the outbreak
    reconstructions with regional drought history. The reconstructions
    reveal repeated western spruce budworm outbreaks that sometimes persisted
    more than a decade and were significantly synchronous among sites.
    Synchrony was higher in the second half of the record, possibly due
    to changes in forest composition and structure brought about by land
    use practices. Across stands and regions, there was a moderately
    strong relationship between initiation of synchronous outbreaks and
    periods of transitional climate conditions in which moisture availability
    was below average prior to outbreak initiation, but above average
    in the first few years of an outbreak. There was a weak relationship
    between cessation of outbreaks and one or more years of high moisture
    availability. Outbreaks tended to occur near the end of droughts.
    The association between climatic variability and outbreak dynamics
    observed across this transect indicates that climate is an important
    driver of western spruce budworm outbreaks. Other factors that we
    did not test, but that may influence outbreak dynamics include stand
    structure, forest composition, predation, and phenological synchrony
    between larvae and host trees. Future changes in western spruce budworm
    outbreak dynamics will be determined by a combination of changing
    climate, interactions with other disturbance agents, and changing
    forest composition and structure. Our results suggest that western
    spruce budworm outbreaks will likely intensify if drought frequency
    increases in the future.
    BibTeX:
    @article{Flower2014a,
      author = {Flower, A. and Gavin, D. G. and Heyerdahl, E. K. and Parsons, R. A. and Cohn, G. M.},
      title = {Drought-triggered western spruce budworm outbreaks in the interior Pacific Northwest: A multi-century dendrochronological record},
      journal = {Forest Ecology and Management},
      year = {2014},
      volume = {324},
      pages = {16--27},
      url = {http://www.sciencedirect.com/science/article/pii/S0378112714001960},
      doi = {http://doi.org/10.1016/j.foreco.2014.03.042}
    }
    					
    Gavin2014 Gavin, D.G.; Fitzpatrick, M.C.; Gugger, P.F.; Heath, K.D.; Rodríguez-Sánchez, F.; Dobrowski, S.Z.; Hampe, A.; Hu, F.S.; Ashcroft, M.B.; Bartlein, P.J.; Blois, J.L.; Carstens, B.C.; Davis, E.B.; de Lafontaine, G.; Edwards, M.E.; Fernandez, M.; Henne, P.D.; Herring, E.M.; Holden, Z.A.; Kong, W.-s.; Liu, J.; Magri, D.; Matzke, N.J.; McGlone, M.S.; Saltré, F.; Stigall, A.L.; Tsai, Y.-H.E. & Williams, J.W. Climate refugia: joint inference from fossil records, species distribution models and phylogeography 2014 New Phytologist
    Vol. 204 , pp. 37-54  
    article climate change, last glacial maximum, migration, paleoecology, phylogeography, range dynamics, species distribution modeling
    Abstract: Contents













    I.



    II. Approaches for reconstructing refugia: strengths, limitations
    and recent advances


    III.



    IV.



    V.



    VI.








    References








    Summary

    Climate refugia, locations where taxa survive periods of regionally
    adverse climate, are thought to be critical for maintaining biodiversity
    through the glacial‚Äďinterglacial climate changes of the Quaternary.
    A critical research need is to better integrate and reconcile the
    three major lines of evidence used to infer the existence of past
    refugia ‚Äď fossil records, species distribution models and phylogeographic
    surveys ‚Äď in order to characterize the complex spatiotemporal trajectories
    of species and populations in and out of refugia. Here we review
    the complementary strengths, limitations and new advances for these
    three approaches. We provide case studies to illustrate their combined
    application, and point the way towards new opportunities for synthesizing
    these disparate lines of evidence. Case studies with European beech,
    Qinghai spruce and Douglas-fir illustrate how the combination of
    these three approaches successfully resolves complex species histories
    not attainable from any one approach. Promising new statistical techniques
    can capitalize on the strengths of each method and provide a robust
    quantitative reconstruction of species history. Studying past refugia
    can help identify contemporary refugia and clarify their conservation
    significance, in particular by elucidating the fine-scale processes
    and the particular geographic locations that buffer species against
    rapidly changing climate.
    BibTeX:
    @article{Gavin2014,
      author = {Gavin, Daniel G. and Fitzpatrick, Matthew C. and Gugger, Paul F. and Heath, Katy D. and Rodríguez-Sánchez, Francisco and Dobrowski, Solomon Z. and Hampe, Arndt and Hu, Feng Sheng and Ashcroft, Michael B. and Bartlein, Patrick J. and Blois, Jessica L. and Carstens, Bryan C. and Davis, Edward B. and de Lafontaine, Guillaume and Edwards, Mary E. and Fernandez, Matias and Henne, Paul D. and Herring, Erin M. and Holden, Zachary A. and Kong, Woo-seok and Liu, Jianquan and Magri, Donatella and Matzke, Nicholas J. and McGlone, Matt S. and Saltré, Frédérik and Stigall, Alycia L. and Tsai, Yi-Hsin Erica and Williams, John W.},
      title = {Climate refugia: joint inference from fossil records, species distribution models and phylogeography},
      journal = {New Phytologist},
      year = {2014},
      volume = {204},
      pages = {37--54},
      url = {http://onlinelibrary.wiley.com/doi/10.1111/nph.12929/abstract},
      doi = {http://doi.org/10.1111/nph.12929}
    }
    					
    Harrison2014 Harrison, S.P.; Bartlein, P.J.; Brewer, S.; Prentice, I.C.; Boyd, M.; Hessler, I.; Holmgren, K.; Izumi, K. & Willis, K. Climate model benchmarking with glacial and mid-Holocene climates 2014 Climate Dynamics
    Vol. 43 (3-4) , pp. 671-688  
    article climate-model evaluation, climate sensitivity, climatology, geophysics/geodesy, last glacial maximum, mid-holocene monsoons, oceanography, palaeoclimate modelling intercomparison project
    Abstract: Past climates provide a test of models’ ability to predict climate
    change. We present a comprehensive evaluation of state-of-the-art
    models against Last Glacial Maximum and mid-Holocene climates, using
    reconstructions of land and ocean climates and simulations from the
    Palaeoclimate Modelling and Coupled Modelling Intercomparison Projects.
    Newer models do not perform better than earlier versions despite
    higher resolution and complexity. Differences in climate sensitivity
    only weakly account for differences in model performance. In the
    glacial, models consistently underestimate land cooling (especially
    in winter) and overestimate ocean surface cooling (especially in
    the tropics). In the mid-Holocene, models generally underestimate
    the precipitation increase in the northern monsoon regions, and overestimate
    summer warming in central Eurasia. Models generally capture large-scale
    gradients of climate change but have more limited ability to reproduce
    spatial patterns. Despite these common biases, some models perform
    better than others.
    BibTeX:
    @article{Harrison2014,
      author = {Harrison, S. P. and Bartlein, P. J. and Brewer, S. and Prentice, I. C. and Boyd, M. and Hessler, I. and Holmgren, K. and Izumi, K. and Willis, K.},
      title = {Climate model benchmarking with glacial and mid-Holocene climates},
      journal = {Climate Dynamics},
      year = {2014},
      volume = {43},
      number = {3-4},
      pages = {671--688},
      url = {http://link.springer.com/article/10.1007/s00382-013-1922-6},
      doi = {http://doi.org/10.1007/s00382-013-1922-6}
    }
    					
    IzumiBartleinHarrison2014 Izumi, K.; Bartlein, P.J. & Harrison, S.P. Energy-balance mechanisms underlying consistent large-scale temperature responses in warm and cold climates 2014 Climate Dynamics
    Vol. 44 (11-12) , pp. 3111-3127  
    article
    Abstract: Climate simulations show consistent large-scale temperature responses including amplified land–ocean contrast, high-latitude/low-latitude contrast, and changes in seasonality in response to year-round forcing, in both warm and cold climates, and these responses are proportional and nearly linear across multiple climate states. We examine the possibility that a small set of common mechanisms controls these large-scale responses using a simple energy-balance model to decompose the temperature changes shown in multiple lgm and abrupt4 x CO 2 simulations from the CMIP5 archive. Changes in the individual components of the energy balance are broadly consistent across the models. Although several components are involved in the overall temperature responses, surface downward clear-sky longwave radiation is the most important component driving land–ocean contrast and high-latitude amplification in both warm and cold climates. Surface albedo also plays a significant role in promoting high-latitude amplification in both climates and in intensifying the land–ocean contrast in the warm climate case. The change in seasonality is a consequence of the changes in land–ocean and high-latitude/low-latitude contrasts rather than an independent temperature response. This is borne out by the fact that no single component stands out as being the major cause of the change in seasonality, and the relative importance of individual components is different in cold and warm climates.
    BibTeX:
    @article{IzumiBartleinHarrison2014,
      author = {Izumi, Kenji and Bartlein, Patrick J. and Harrison, Sandy P.},
      title = {Energy-balance mechanisms underlying consistent large-scale temperature responses in warm and cold climates},
      journal = {Climate Dynamics},
      year = {2014},
      volume = {44},
      number = {11-12},
      pages = {3111--3127},
      url = {http://link.springer.com/article/10.1007/s00382-014-2189-2},
      doi = {http://doi.org/10.1007/s00382-014-2189-2}
    }
    					
    MarshallRoeringBartleinEtAl2014 Marshall, J.A.; Roering, J.J.; Bartlein, P.J.; Praskievicz, S.J.; Gavin, D.G.; Hales, T.C. & Granger, D.E. Does Temperature (Rather than Precipitation) Dictate the Geomorphic Legacy of Glacial Intervals in Unglaciated Mid-Latitude Terrains? 2014 AGU Fall Meeting Abstracts
    Vol. 14  
    inproceedings 1030 geochemical cycles, 1039 alteration and weathering processes, 1105 quaternary geochronology, 1625 geomorphology and weathering, geochemistry, geochronology, global change
    Abstract: Whereas glaciated landscapes record increased erosional efficiency
    through moraines and U-shaped valleys, unglaciated hillslopes and rivers
    lack a mechanistic theory for climate controls on their dynamics and
    form. Changes in precipitation and associated aggradation due to
    vegetation loss or incision due to increased river discharge are
    commonly invoked when considering the effect of glacial intervals on
    unglaciated terrains, but there is scant evidence supporting or
    discounting these hypotheses. Surprisingly, there is little
    consideration that temperature, rather than precipitation, may dictate
    the frequency, magnitude, or style of erosion in unglaciated landscapes
    during glacial intervals. Here, we present results combining a
    mechanistic frost-cracking model with downscaled general circulation
    model output to predict the extent and intensity of sediment production
    via frost processes across the unglaciated Oregon Coast Range (OCR)
    during the Last Glacial Maximum (LGM). Our results show that in this
    mid-latitude region, well south of the Cordilleran ice sheet,
    frost-driven processes likely shaped 90% of the present-day landmass
    during the LGM. A suite of geomorphic and vegetation data from a 50-ky
    sediment core from a paleo landslide-dammed lake in the OCR support our
    model results. Our study site, Little Lake, is located in the central
    portion of the OCR, over 400 m south of the maximum extent of the
    Cordilleran ice sheet. Based on 10Be-derived erosion rates, present-day
    catchment erosion rates average 0.07 Ī 0.03 mm/yr (mean Ī
    sd), while LGM erosion rates remained constant around 0.19 Ī 0.01
    mm/yr. These LGM values are nearly 3X greater than present-day erosion
    rates and coincide with high frost cracking intensity predicted by our
    model. We also observe a transition from finely laminated lacustrine
    clays and sands to coarse lacustrine blue-grey sands at ˜ 28 ka, during
    the transition to the LGM. The presence of Picea sitchensis (Sitka
    spruce) and Abies lasiocarpa (subalpine fir) in the core during the LGM
    imply mean annual temperatures of ˜ 1 °C and January mean
    temperatures of ˜ -7 °C. Our results suggest that broad swaths of
    continental landscapes likely experienced accelerated sediment
    production via frost processes rather than via changes in precipitation
    during glacial intervals.
    BibTeX:
    @article{MarshallRoeringBartleinEtAl2014,
      author = {Marshall, J. A. and Roering, J. J. and Bartlein, P. J. and Praskievicz, S. J. and Gavin, D. G. and Hales, T. C. and Granger, D. E.},
      title = {Does Temperature (Rather than Precipitation) Dictate the Geomorphic Legacy of Glacial Intervals in Unglaciated Mid-Latitude Terrains?},
      journal = {AGU Fall Meeting Abstracts},
      year = {2014},
      volume = {14},
      url = {http://adsabs.harvard.edu/abs/2014AGUFMEP14B..08M}
    }
    					
    McLauchlan2014 McLauchlan, K.K.; Higuera, P.E.; Gavin, D.G.; Perakis, S.S.; Mack, M.C.; Alexander, H.; Battles, J.; Biondi, F.; Buma, B.; Colombaroli, D.; Enders, S.K.; Engstrom, D.R.; Hu, F.S.; Marlon, J.R.; Marshall, J.; Mcglone, M.; Morris, J.L.; Nave, L.E.; Shuman, B.; Smithwick, E.A.H.; Urrego, D.H.; Wardle, D.A.; Williams, C.J. & Williams, J.J. Reconstructing disturbances and their biogeochemical consequences over multiple timescales 2014 Bioscience
    Vol. 64 (2) , pp. 105-116  
    article carbon, climate-change, disturbance, early holocene, ecosystem ecology, fire regime, lake-sediments, national-park, nitrogen cycling, north-america, olympic peninsula, resilience, sediment-charcoal records, sub-alpine forests, vegetation change
    Abstract: Ongoing changes in disturbance regimes are predicted to cause acute
    changes in ecosystem structure and function in the coming decades,
    but many aspects of these predictions are uncertain. A key challenge
    is to improve the predictability of postdisturbance biogeochemical
    trajectories at the ecosystem level. Ecosystem ecologists and paleoecologists
    have generated complementary data sets about disturbance (type, severity,
    frequency) and ecosystem response (net primary productivity, nutrient
    cycling) spanning decadal to millennial timescales. Here, we take
    the first steps toward a full integration of these data sets by reviewing
    how disturbances are reconstructed using dendrochronological and
    sedimentary archives and by summarizing the conceptual frameworks
    for carbon, nitrogen, and hydrologic responses to disturbances. Key
    research priorities include further development of paleoecological
    techniques that reconstruct both disturbances and terrestrial ecosystem
    dynamics. In addition, mechanistic detail from disturbance experiments,
    long-term observations, and chronosequences can help increase the
    understanding of ecosystem resilience.
    BibTeX:
    @article{McLauchlan2014,
      author = {McLauchlan, Kendra K. and Higuera, Philip E. and Gavin, Daniel G. and Perakis, Steven S. and Mack, Michelle C. and Alexander, Heather and Battles, John and Biondi, Franco and Buma, Brian and Colombaroli, Daniele and Enders, Sara K. and Engstrom, Daniel R. and Hu, Feng Sheng and Marlon, Jennifer R. and Marshall, John and Mcglone, Matt and Morris, Jesse L. and Nave, Lucas E. and Shuman, Bryan and Smithwick, Erica A. H. and Urrego, Dunia H. and Wardle, David A. and Williams, Christopher J. and Williams, Joseph J.},
      title = {Reconstructing disturbances and their biogeochemical consequences over multiple timescales},
      journal = {Bioscience},
      year = {2014},
      volume = {64},
      number = {2},
      pages = {105--116},
      doi = {http://doi.org/10.1093/biosci/bit017}
    }
    					
    Schmidt2014 Schmidt, G.A.; Annan, J.D.; Bartlein, P.J.; Cook, B.I.; Guilyardi, E.; Hargreaves, J.C.; Harrison, S.P.; Kageyama, M.; LeGrande, A.N.; Konecky, B.; Lovejoy, S.; Mann, M.E.; Masson-Delmotte, V.; Risi, C.; Thompson, D.; Timmermann, A.; Tremblay, L.-B. & Yiou, P. Using palaeo-climate comparisons to constrain future projections in CMIP5 2014 Clim. Past
    Vol. 10 (1) , pp. 221-250  
    article
    Abstract: We present a selection of methodologies for using the palaeo-climate
    model component of the Coupled Model Intercomparison Project (Phase
    5) (CMIP5) to attempt to constrain future climate projections using
    the same models. The constraints arise from measures of skill in
    hindcasting palaeo-climate changes from the present over three periods:
    the Last Glacial Maximum (LGM) (21 000 yr before present, ka),
    the mid-Holocene (MH) (6 ka) and the Last Millennium (LM) (850‚Äď1850
    CE). The skill measures may be used to validate robust patterns
    of climate change across scenarios or to distinguish between models
    that have differing outcomes in future scenarios. We find that the
    multi-model ensemble of palaeo-simulations is adequate for addressing
    at least some of these issues. For example, selected benchmarks for
    the LGM and MH are correlated to the rank of future projections
    of precipitation/temperature or sea ice extent to indicate that models
    that produce the best agreement with palaeo-climate information give
    demonstrably different future results than the rest of the models.
    We also explore cases where comparisons are strongly dependent on
    uncertain forcing time series or show important non-stationarity,
    making direct inferences for the future problematic. Overall, we
    demonstrate that there is a strong potential for the palaeo-climate
    simulations to help inform the future projections and urge all the
    modelling groups to complete this subset of the CMIP5 runs.
    BibTeX:
    @article{Schmidt2014,
      author = {Schmidt, G. A. and Annan, J. D. and Bartlein, P. J. and Cook, B. I. and Guilyardi, E. and Hargreaves, J. C. and Harrison, S. P. and Kageyama, M. and LeGrande, A. N. and Konecky, B. and Lovejoy, S. and Mann, M. E. and Masson-Delmotte, V. and Risi, C. and Thompson, D. and Timmermann, A. and Tremblay, L.-B. and Yiou, P.},
      title = {Using palaeo-climate comparisons to constrain future projections in CMIP5},
      journal = {Clim. Past},
      year = {2014},
      volume = {10},
      number = {1},
      pages = {221--250},
      url = {http://www.clim-past.net/10/221/2014/},
      doi = {http://doi.org/10.5194/cp-10-221-2014}
    }
    					
    ShaferBartlein2014 Shafer, S.L. & Bartlein, P.J. Projected Future Climate Analogues and Climate "Velocities" in North America 2014 AGU Fall Meeting Abstracts
    Vol. 53  
    inproceedings 1626 global climate models, 1630 impacts of global change, 1637 regional climate change, 6309 decision making under uncertainty
    Abstract: Future climate changes may have significant effects on many North American ecosystems. One way of assessing the potential impacts of future climate change is to use future climate analogues of present climate to evaluate the spatial extent and rates of future climate change. We used a set of Coupled Model Intercomparison Project phase 5 (CMIP5) coupled atmosphere-ocean general circulation model (AOGCM) future climate simulations (2006-2100) produced under representative concentration pathway scenario RCP8.5. We regridded these data to a 10-km equal-area grid of North America. Modern climate data (1961-1990 30-year mean) were interpolated to the same 10-km grid. The projected future climate data were analyzed using 10-year mean values of monthly and seasonal temperature and precipitation and a set of derived annual bioclimatic variables (e.g., growing degree days) considered to be ecologically significant. Potential future climate analogues were calculated for each grid cell using Euclidean distances to identify similar climates occurring elsewhere in North America. We identify regions that are projected to retain climates similar to present in the future (e.g., parts of the southeastern United States) and regions where present climates are projected to become less common or to disappear in the future (e.g., high elevation sites in western North America). We also calculate the rates of change in locations of similar climates (i.e., climate analogue velocities) and compare our results with simulated paleoclimate velocities over the past 22 kyr (from TraCE-21ka transient climate simulations for 22 ka-present). We discuss the implications of these results for conservation and natural resource management in North America. We also describe a web application being developed to allow researchers, decision makers, and members of the public, to visualize, explore, and use the climate analogue data.
    BibTeX:
    @article{ShaferBartlein2014,
      author = {Shafer, S. L. and Bartlein, P. J.},
      title = {Projected Future Climate Analogues and Climate "Velocities" in North America},
      journal = {AGU Fall Meeting Abstracts},
      year = {2014},
      volume = {53},
      url = {http://adsabs.harvard.edu/abs/2014AGUFMGC53A0484S}
    }
    					
    Dawson2013 Dawson, M.N.; Algar, A.C.; Antonelli, A.; D√°valos, L.M.; Davis, E.; Early, R.; Guisan, A.; Jansson, R.; Lessard, J.-P.; Katharine, M.A.; McGuire, J.; Stigall, A.L.; Swenson, N.G.; Zimmermann, N. & Gavin, D.G. An horizon scan of biogeography 2013 Frontiers of Biogeography
    Vol. 5 (2)  
    article
    Abstract: The opportunity to reflect broadly on the accomplishments, prospects,
    and reach of a field may present itself relatively infrequently.
    Each biennial meeting of the International Biogeography Society showcases
    ideas solicited and developed largely during the preceding year,
    by individuals or teams from across the breadth of the discipline.
    Here, we highlight challenges, developments, and opportunities in
    biogeography from that biennial synthesis. We note the realized and
    potential impact of rapid data accumulation in several fields, a
    renaissance for inter-disciplinary research, the importance of recognizing
    the evolution-ecology continuum across spatial and temporal scales
    and at different taxonomic, phylogenetic and functional levels, and
    re-exploration of classical assumptions and hypotheses using new
    tools. However, advances are taxonomically and geographically biased,
    key theoretical frameworks await tools to handle, or strategies to
    simplify, the biological complexity seen in empirical systems. Current
    threats to biodiversity require unprecedented integration of knowledge
    and development of predictive capacity that may enable biogeography
    to unite its descriptive and hypothetico-deductive branches and establish
    a greater role within and outside academia.
    BibTeX:
    @article{Dawson2013,
      author = {Dawson, Michael N. and Algar, Adam C. and Antonelli, Alexandre and D√°valos, Liliana M. and Davis, Edward and Early, Regan and Guisan, Antoine and Jansson, Roland and Lessard, Jean-Philippe and Katharine, Marske A. and McGuire, Jenny and Stigall, Alycia L. and Swenson, Nathan G. and Zimmermann, Niklaus and Gavin, Daniel G.},
      title = {An horizon scan of biogeography},
      journal = {Frontiers of Biogeography},
      year = {2013},
      volume = {5},
      number = {2},
      url = {http://escholarship.org/uc/item/9rp9c1qk}
    }
    					
    Fonstad2013 Fonstad, M.A. Geographies of Water INTRODUCTION 2013 Annals of the Association of American Geographers
    Vol. 103 (2) , pp. 251-252  
    article
    BibTeX:
    @article{Fonstad2013,
      author = {Fonstad, Mark A.},
      title = {Geographies of Water INTRODUCTION},
      journal = {Annals of the Association of American Geographers},
      year = {2013},
      volume = {103},
      number = {2},
      pages = {251--252},
      doi = {http://doi.org/10.1080/00045608.2013.757159}
    }
    					
    Gavin2013 Gavin, D.G.; Anderson, M. & Roering, J.J. Potential late-Holocene disjunction of Sequoia sempervirens on the central Oregon Coast 2013 Northwest Science
    Vol. 87 (2) , pp. 81-94  
    article
    Abstract: A large (textgreater 200-cm diameter) coast redwood (Sequoia sempervirens)
    stump occurring upright on an Oregon beach, 257 km from the northern
    limit of its native distribution, may be a remnant of an extinct
    disjunct population or it may be the result of vertical emplacement
    of a drift log. Holocene tree stumps in situ in paleosols commonly
    emerge on the shore platform as a result of a complex history of
    dune activity, subsidence, and erosion. An historical account reported
    organic soils associated with the stump during the late 1800s; such
    soils are normally removed quickly by wave action after exposure.
    We used several methods to corroborate this account. The stump's
    in situ origin is supported by 1) a radiocarbon age indicating a
    death date between 1820 and 1720 years ago, coeval with other paleosols
    and in situ stumps; 2) its height and upright position, which are
    only matched by other in situ stumps; and 3) a photograph from 1912
    showing uneroded wood inconsistent with a sea-drift history. Other
    evidence failed to support the in situ origin: 1) ground-penetrating
    radar did not reveal an associated paleosol, 2) the age of a nearby
    paleosols and stumps within 3 km were younger than the stump, and
    3) three paleosols did not yield redwood pollen or wood. The only
    support for a sea-drift origin is that its age slightly predates
    a known tsunami that may have emplaced the stump. The balance of
    evidence suggests that the redwood stump is a remnant of an extinct
    late-Holocene disjunct population.
    BibTeX:
    @article{Gavin2013,
      author = {Gavin, Daniel G. and Anderson, Michael and Roering, Joshua J.},
      title = {Potential late-Holocene disjunction of Sequoia sempervirens on the central Oregon Coast},
      journal = {Northwest Science},
      year = {2013},
      volume = {87},
      number = {2},
      pages = {81--94},
      url = {http://www.bioone.org/doi/abs/10.3955/046.087.0201},
      doi = {http://doi.org/10.3955/046.087.0201}
    }
    					
    Gavin2013a Gavin, D.G.; Brubaker, L.B. & Greenwald, D.N. Postglacial climate and fire-mediated vegetation change on the western Olympic Peninsula, Washington (USA) 2013 Ecological Monographs
    Vol. 83 (4) , pp. 471-489  
    article alternate stable states, charcoal, fire history, old growth forests, pollen analysis
    Abstract: The mode and tempo of forest compositional change during periods of
    rapid climate change, including the potential for the fire regime
    to produce nonlinear relationships between climate and vegetation,
    is a long-standing theme of forest ecological research. In the old
    conifer forests of the coastal Pacific Northwest, fire disturbances
    are sufficiently rare that their relation to climate and their ecological
    effects are poorly understood. We used a 14‚Ää700-year high-resolution
    sediment record from Yahoo Lake on the Olympic Peninsula, Washington,
    USA, to examine vegetation (landscape vegetation from pollen and
    local vegetation from macrofossils) and fire (landscape fire from
    total charcoal and local fire from charcoal peaks) in conjunction
    with independent records of climate. We hypothesized that the successional
    stage of the local forest will exhibit alternate stable states over
    a range of fire activity, that species turnover will increase abruptly
    above a certain level of fire activity and that both responses would
    be more gradual at the landscape scale than the local scale. Supporting
    these hypotheses, at the local scale, we found strong evidence for
    alternate stable states of late vs. early successional communities
    and inertia of species turnover to changing fire activity. At the
    landscape scale, vegetation responded more gradually to changing
    fire activity. From 14‚Ää700 to 7000 years ago, high landscape vegetation
    turnover occurred along with high landscape fire activity, especially
    during the warm summers of the early Holocene. In several instances,
    local species turned over completely following fire events but several
    centuries after climate change. In contrast, during the last 7000
    years, the local forest composition was dominated by late-successional
    species with little species turnover, despite periods of moderate
    fire activity. We suggest that the relatively minor climate fluctuations
    of the past 7000 years were not sufficient to cause large-scale species
    turnover after fire. The Yahoo Lake fire and vegetation record of
    the early Holocene provides a model for dramatic ecosystem change
    following an anticipated shift to warmer summer temperatures.
    BibTeX:
    @article{Gavin2013a,
      author = {Gavin, Daniel G. and Brubaker, Linda B. and Greenwald, D. Noah},
      title = {Postglacial climate and fire-mediated vegetation change on the western Olympic Peninsula, Washington (USA)},
      journal = {Ecological Monographs},
      year = {2013},
      volume = {83},
      number = {4},
      pages = {471--489},
      url = {http://www.esajournals.org/doi/full/10.1890/12-1742.1},
      doi = {http://doi.org/10.1890/12-1742.1}
    }
    					
    Hampe2013 Hampe, A.; Rodriguez-Sanchez, F.; Dobrowski, S.; Hu, F.S. & Gavin, D.G. Climate refugia: from the Last Glacial Maximum to the twenty-first century 2013 New Phytologist
    Vol. 197 (1) , pp. 16-18  
    article biodiversity, climate change, future, glacial refugia, global warming, last glacial maximum, microrefugia, paleobiogeography, species distribution modeling (sdm)
    BibTeX:
    @article{Hampe2013,
      author = {Hampe, Arndt and Rodriguez-Sanchez, Francisco and Dobrowski, Solomon and Hu, Feng Sheng and Gavin, Daniel G.},
      title = {Climate refugia: from the Last Glacial Maximum to the twenty-first century},
      journal = {New Phytologist},
      year = {2013},
      volume = {197},
      number = {1},
      pages = {16--18},
      doi = {http://doi.org/10.1111/nph.12059}
    }
    					
    Li2013 Li, G.; Harrison, S.P.; Bartlein, P.J.; Izumi, K. & Colin Prentice, I. Precipitation scaling with temperature in warm and cold climates: An analysis of CMIP5 simulations 2013 Geophysical Research Letters
    Vol. 40 (15) , pp. 4018-4024  
    article 1610 atmosphere, 1620 climate dynamics, 1626 global climate models, 1631 land/atmosphere interactions, 1655 water cycles, clausius-clapeyron relationship, evaporation, global water cycle, land-surface model, paleoclimate reconstructions, precipitation scaling
    Abstract: We investigate the scaling between precipitation and temperature changes
    in warm and cold climates using six models that have simulated the
    response to both increased CO2 and Last Glacial Maximum (LGM)
    boundary conditions. Globally, precipitation increases in warm climates
    and decreases in cold climates by between 1.5¬įC and 3¬įC.
    Precipitation sensitivity to temperature changes is lower over the
    land than over the ocean and lower over the tropical land than over
    the extratropical land, reflecting the constraint of water availability.
    The wet tropics get wetter in warm climates and drier in cold climates,
    but the changes in dry areas differ among models. Seasonal changes
    of tropical precipitation in a warmer world also reflect this “rich
    get richer‚ÄĚ syndrome. Precipitation seasonality is decreased in
    the cold-climate state. The simulated changes in precipitation per
    degree temperature change are comparable to the observed changes
    in both the historical period and the LGM.
    BibTeX:
    @article{Li2013,
      author = {Li, Guangqi and Harrison, Sandy P. and Bartlein, Patrick J. and Izumi, Kenji and Colin Prentice, I.},
      title = {Precipitation scaling with temperature in warm and cold climates: An analysis of CMIP5 simulations},
      journal = {Geophysical Research Letters},
      year = {2013},
      volume = {40},
      number = {15},
      pages = {4018--4024},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/grl.50730/abstract},
      doi = {http://doi.org/10.1002/grl.50730}
    }
    					
    Marlon2013 Marlon, J.R.; Bartlein, P.J.; Daniau, A.-L.; Harrison, S.P.; Maezumi, S.Y.; Power, M.J.; Tinner, W. & Vanniére, B. Global biomass burning: a synthesis and review of Holocene paleofire records and their controls 2013 Quaternary Science Reviews
    Vol. 65 , pp. 5-25  
    article biomass burning, charcoal, early anthropocene hypothesis, fire, holocene, paleoclimate, paleofire
    Abstract: We synthesize existing sedimentary charcoal records to reconstruct
    Holocene fire history at regional, continental and global scales.
    The reconstructions are compared with the two potential controls
    of burning at these broad scales ‚Äď changes in climate and human
    activities ‚Äď to assess their relative importance on trends in biomass
    burning. Here we consider several hypotheses that have been advanced
    to explain the Holocene record of fire, including climate, human
    activities and synergies between the two. Our results suggest that
    1) episodes of high fire activity were relatively common in the early
    Holocene and were consistent with climate changes despite low global
    temperatures and low levels of biomass burning globally; 2) there
    is little evidence from the paleofire record to support the Early
    Anthropocene Hypothesis of human modification of the global carbon
    cycle; 3) there was a nearly-global increase in fire activity from
    3 to 2 ka that is difficult to explain with either climate or humans,
    but the widespread and synchronous nature of the increase suggests
    at least a partial climate forcing; and 4) burning during the past
    century generally decreased but was spatially variable; it declined
    sharply in many areas, but there were also large increases (e.g.,
    Australia and parts of Europe). Our analysis does not exclude an
    important role for human activities on global biomass burning during
    the Holocene, but instead provides evidence for a pervasive influence
    of climate across multiple spatial and temporal scales.
    BibTeX:
    @article{Marlon2013,
      author = {Marlon, Jennifer R. and Bartlein, Patrick J. and Daniau, Anne-Laure and Harrison, Sandy P. and Maezumi, Shira Y. and Power, Mitchell J. and Tinner, Willy and Vanniére, Boris},
      title = {Global biomass burning: a synthesis and review of Holocene paleofire records and their controls},
      journal = {Quaternary Science Reviews},
      year = {2013},
      volume = {65},
      pages = {5--25},
      url = {http://www.sciencedirect.com/science/article/pii/S0277379112005318},
      doi = {http://doi.org/10.1016/j.quascirev.2012.11.029}
    }
    					
    Morey2013 Morey, A.E.; Goldfinger, C.; Briles, C.E.; Gavin, D.G.; Colombaroli, D. & Kusler, J.E. Are great Cascadia earthquakes recorded in the sedimentary records from small forearc lakes? 2013 Nat. Hazards Earth Syst. Sci.
    Vol. 13 (10) , pp. 2441-2463  
    article
    Abstract: Here we investigate sedimentary records from four small inland lakes
    located in the southern Cascadia forearc region for evidence of earthquakes.
    Three of these lakes are in the Klamath Mountains near the Oregon‚ÄďCalifornia
    border, and one is in the central Oregon Coast range. The sedimentary
    sequences recovered from these lakes are composed of normal lake
    sediment interbedded with disturbance event layers. The thickest
    of these layers are graded, and appear to be turbidites or linked
    debrites (turbidites with a basal debris-flow deposit), suggesting
    rapid deposition. Variations in particle size and organic content
    of these layers are reflected in the density and magnetic susceptibility
    data. The frequency and timing of these events, based on radiocarbon
    ages from detrital organics, is similar to the offshore seismogenic
    turbidite record from trench and slope basin cores along the Cascadia
    margin. Stratigraphic correlation of these anomalous deposits based
    on radiocarbon ages, down-core density, and magnetic susceptibility
    data between lake and offshore records suggest synchronous triggering.
    The areal extent and multiple depositional environments over which
    these events appear to correlate suggest that these deposits were
    most likely caused by shaking during great Cascadia earthquakes.
    BibTeX:
    @article{Morey2013,
      author = {Morey, A. E. and Goldfinger, C. and Briles, C. E. and Gavin, D. G. and Colombaroli, D. and Kusler, J. E.},
      title = {Are great Cascadia earthquakes recorded in the sedimentary records from small forearc lakes?},
      journal = {Nat. Hazards Earth Syst. Sci.},
      year = {2013},
      volume = {13},
      number = {10},
      pages = {2441--2463},
      url = {http://www.nat-hazards-earth-syst-sci.net/13/2441/2013/},
      doi = {http://doi.org/10.5194/nhess-13-2441-2013}
    }
    					
    Power2013 Power, M.J.; Mayle, F.E.; Bartlein, P.J.; Marlon, J.R.; Anderson, R.S.; Behling, H.; Brown, K.J.; Carcaillet, C.; Colombaroli, D.; Gavin, D.G.; Hallett, D.J.; Horn, S.P.; Kennedy, L.M.; Lane, C.S.; Long, C.J.; Moreno, P.I.; Paitre, C.; Robinson, G.; Taylor, Z. & Walsh, M.K. Climatic control of the biomass-burning decline in the Americas after AD 1500 2013 Holocene
    Vol. 23 (1) , pp. 3-13  
    article 'little ice age', amazonia, atmospheric co2, biomass burning, charcoal, climate, fire, forest, holocene, human population, ice-age, last millennium, past millennium, record, southern patagonia
    Abstract: The significance and cause of the decline in biomass burning across
    the Americas after AD 1500 is a topic of considerable debate. We
    synthesized charcoal records (a proxy for biomass burning) from the
    Americas and from the remainder of the globe over the past 2000 years,
    and compared these with paleoclimatic records and population reconstructions.
    A distinct post-AD 1500 decrease in biomass burning is evident,
    not only in the Americas, but also globally, and both are similar
    in duration and timing to 'Little Ice Age' climate change. There
    is temporal and spatial variability in the expression of the biomass-burning
    decline across the Americas but, at a regional-continental scale,
    'Little Ice Age' climate change was likely more important than
    indigenous population collapse in driving this decline.
    BibTeX:
    @article{Power2013,
      author = {Power, M. J. and Mayle, F. E. and Bartlein, P. J. and Marlon, J. R. and Anderson, R. S. and Behling, H. and Brown, K. J. and Carcaillet, C. and Colombaroli, D. and Gavin, D. G. and Hallett, D. J. and Horn, S. P. and Kennedy, L. M. and Lane, C. S. and Long, C. J. and Moreno, P. I. and Paitre, C. and Robinson, G. and Taylor, Z. and Walsh, M. K.},
      title = {Climatic control of the biomass-burning decline in the Americas after AD 1500},
      journal = {Holocene},
      year = {2013},
      volume = {23},
      number = {1},
      pages = {3--13},
      doi = {http://doi.org/10.1177/0959683612450196}
    }
    					
    Braconnot2012 Braconnot, P.; Harrison, S.P.; Kageyama, M.; Bartlein, P.J.; Masson-Delmotte, V.; Abe-Ouchi, A.; Otto-Bliesner, B. & Zhao, Y. Evaluation of climate models using palaeoclimatic data 2012 Nature Climate Change
    Vol. 2 (6) , pp. 417-424  
    article african monsoon, boundary-conditions, intercomparison project, last glacial maximum, north-atlantic, palaeovegetation data, pmip2 coupled simulations, regional climate, sea-surface temperatures, synergistic feedbacks
    Abstract: There is large uncertainty about the magnitude of warming and how
    rainfall patterns will change in response to any given scenario of
    future changes in atmospheric composition and land use. The models
    used for future climate projections were developed and calibrated
    using climate observations from the past 40 years. The geologic record
    of environmental responses to climate changes provides a unique opportunity
    to test model performance outside this limited climate range. Evaluation
    of model simulations against palaeodata shows that models reproduce
    the direction and large-scale patterns of past changes in climate,
    but tend to underestimate the magnitude of regional changes. As part
    of the effort to reduce model-related uncertainty and produce more
    reliable estimates of twenty-first century climate, the Palaeoclimate
    Modelling Intercomparison Project is systematically applying palaeoevaluation
    techniques to simulations of the past run with the models used to
    make future projections. This evaluation will provide assessments
    of model performance, including whether a model is sufficiently sensitive
    to changes in atmospheric composition, as well as providing estimates
    of the strength of biosphere and other feedbacks that could amplify
    the model response to these changes and modify the characteristics
    of climate variability.
    BibTeX:
    @article{Braconnot2012,
      author = {Braconnot, Pascale and Harrison, Sandy P. and Kageyama, Masa and Bartlein, Patrick J. and Masson-Delmotte, Valerie and Abe-Ouchi, Ayako and Otto-Bliesner, Bette and Zhao, Yan},
      title = {Evaluation of climate models using palaeoclimatic data},
      journal = {Nature Climate Change},
      year = {2012},
      volume = {2},
      number = {6},
      pages = {417--424},
      doi = {http://doi.org/10.1038/NCLIMATE1456}
    }
    					
    Carbonneau2012 Carbonneau, P.; Fonstad, M.A.; Marcus, W.A. & Dugdale, S.J. Making riverscapes real 2012 Geomorphology
    Vol. 137 (1) , pp. 74-86  
    article aerial-photography, atlantic salmon, geomorphology, grain-size, gravel-bed rivers, habitat-selection, high-resolution, landscape ecology, patch dynamics, remote sensing, riverine habitat, rivers, salmon salmo-salar, spatial-pattern
    Abstract: The structure and function of rivers have long been characterized
    either by: (1) qualitative models such as the River Continuum Concept
    or Serial Discontinuity Concept which paint broad descriptive portraits
    of how river habitats and communities vary, or (2) quantitative models,
    such as downstream hydraulic geometry, which rely on a limited number
    of measurements spread widely throughout a river basin. In contrast,
    authors such as Fausch et al. (2002) and Wiens (2002) proposed applying
    existing quantitative, spatially comprehensive ecology and landscape
    ecology methods to rivers. This new framework for river sciences
    which preserves variability and spatial relationships is called a
    riverine landscape or a 'riverscape'. Application of this riverscape
    concept requires information on the spatial distribution of organism-scale
    habitats throughout entire river systems. This article examines the
    ways in which recent technical and methodological developments can
    allow us to quantitatively implement and realize the riverscape concept.
    Using 3-cm true color aerial photos and 5-m resolution elevation
    data from the River Tromie, Scotland, we apply the newly developed
    Fluvial Information System which integrates a suite of cutting edge,
    high resolution, remote sensing methods in a spatially explicit framework.
    This new integrated approach allows for the extraction of primary
    fluvial variables such as width, depth, particle size, and elevation.
    From these first-order variables, we derive second-order geomorphic
    and hydraulic variables including velocity, stream power, Froude
    number and shear stress. Channel slope can be approximated from available
    topographic data. Based on these first and second-order variables,
    we produce riverscape metrics that begin to explore how geomorphic
    structures may influence river habitats, including connectivity,
    patchiness of habitat, and habitat distributions. The results show
    a complex interplay of geomorphic variable and habitat patchiness
    that is not predicted by existing fluvial theory. Riverscapes, thus,
    challenge the existing understanding of how rivers structure themselves
    and will force development of new paradigms. (C) 2011 Elsevier B.V.
    All rights reserved.
    BibTeX:
    @article{Carbonneau2012,
      author = {Carbonneau, Patrice and Fonstad, Mark A. and Marcus, W. Andrew and Dugdale, Stephen J.},
      title = {Making riverscapes real},
      journal = {Geomorphology},
      year = {2012},
      volume = {137},
      number = {1},
      pages = {74--86},
      doi = {http://doi.org/10.1016/j.geomorph.2010.09.030}
    }
    					
    Clark2012 Clark, P.U.; Shakun, J.D.; Baker, P.A.; Bartlein, P.J.; Brewer, S.; Brook, E.; Carlson, A.E.; Cheng, H.; Kaufman, D.S.; Liu, Z.; Marchitto, T.M.; Mix, A.C.; Morrill, C.; Otto-Bliesner, B.L.; Pahnke, K.; Russell, J.M.; Whitlock, C.; Adkins, J.F.; Blois, J.L.; Clark, J.; Colman, S.M.; Curry, W.B.; Flower, B.P.; He, F.; Johnson, T.C.; Lynch-Stieglitz, J.; Markgraf, V.; McManus, J.; Mitrovica, J.X.; Moreno, P.I. & Williams, J.W. Global climate evolution during the last deglaciation 2012 Proceedings of the National Academy of Sciences of the United States of America
    Vol. 109 (19) , pp. E1134-E1142  
    article atmospheric co2, eastern north-america, glacial maximum, late-quaternary, millennial-scale changes, pacific-ocean, past 25,000 years, southern-ocean, thermohaline circulation, younger dryas
    Abstract: Deciphering the evolution of global climate from the end of the Last
    Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents
    an outstanding opportunity for understanding the transient response
    of Earth's climate system to external and internal forcings. During
    this interval of global warming, the decay of ice sheets caused global
    mean sea level to rise by approximately 80 m; terrestrial and marine
    ecosystems experienced large disturbances and range shifts; perturbations
    to the carbon cycle resulted in a net release of the greenhouse gases
    CO2 and CH4 to the atmosphere; and changes in atmosphere and
    ocean circulation affected the global distribution and fluxes of
    water and heat. Here we summarize a major effort by the paleoclimate
    research community to characterize these changes through the development
    of well-dated, high-resolution records of the deep and intermediate
    ocean as well as surface climate. Our synthesis indicates that the
    super-position of two modes explains much of the variability in regional
    and global climate during the last deglaciation, with a strong association
    between the first mode and variations in greenhouse gases, and between
    the second mode and variations in the Atlantic meridional overturning
    circulation.
    BibTeX:
    @article{Clark2012,
      author = {Clark, Peter U. and Shakun, Jeremy D. and Baker, Paul A. and Bartlein, Patrick J. and Brewer, Simon and Brook, Ed and Carlson, Anders E. and Cheng, Hai and Kaufman, Darrell S. and Liu, Zhengyu and Marchitto, Thomas M. and Mix, Alan C. and Morrill, Carrie and Otto-Bliesner, Bette L. and Pahnke, Katharina and Russell, James M. and Whitlock, Cathy and Adkins, Jess F. and Blois, Jessica L. and Clark, Jorie and Colman, Steven M. and Curry, William B. and Flower, Ben P. and He, Feng and Johnson, Thomas C. and Lynch-Stieglitz, Jean and Markgraf, Vera and McManus, Jerry and Mitrovica, Jerry X. and Moreno, Patricio I. and Williams, John W.},
      title = {Global climate evolution during the last deglaciation},
      journal = {Proceedings of the National Academy of Sciences of the United States of America},
      year = {2012},
      volume = {109},
      number = {19},
      pages = {E1134--E1142},
      doi = {http://doi.org/10.1073/pnas.1116619109}
    }
    					
    Daniau2012 Daniau, A.-L.; Bartlein, P.J.; Harrison, S.P.; Prentice, I.C.; Brewer, S.; Friedlingstein, P.; Harrison-Prentice, T.I.; Inoue, J.; Izumi, K.; Marlon, J.R.; Mooney, S.; Power, M.J.; Stevenson, J.; Tinner, W.; Andric, M.; Atanassova, J.; Behling, H.; Black, M.; Blarquez, O.; Brown, K.J.; Carcaillet, C.; Colhoun, E.A.; Colombaroli, D.; Davis, B. a.S.; D'Costa, D.; Dodson, J.; Dupont, L.; Eshetu, Z.; Gavin, D.G.; Genries, A.; Haberle, S.; Hallett, D.J.; Hope, G.; Horn, S.P.; Kassa, T.G.; Katamura, F.; Kennedy, L.M.; Kershaw, P.; Krivonogov, S.; Long, C.; Magri, D.; Marinova, E.; McKenzie, G.M.; Moreno, P.I.; Moss, P.; Neumann, F.H.; Norstrom, E.; Paitre, C.; Rius, D.; Roberts, N.; Robinson, G.S.; Sasaki, N.; Scott, L.; Takahara, H.; Terwilliger, V.; Thevenon, F.; Turner, R.; Valsecchi, V.G.; Vanniere, B.; Walsh, M.; Williams, N. & Zhang, Y. Predictability of biomass burning in response to climate changes 2012 Global Biogeochemical Cycles
    Vol. 26  
    article area, emissions, fire regimes, forest-fires, greenland ice, high-resolution, holocene, united-states, variability, wildfires
    Abstract: Climate is an important control on biomass burning, but the sensitivity
    of fire to changes in temperature and moisture balance has not been
    quantified. We analyze sedimentary charcoal records to show that
    the changes in fire regime over the past 21,000 yrs are predictable
    from changes in regional climates. Analyses of paleo-fire data show
    that fire increases monotonically with changes in temperature and
    peaks at intermediate moisture levels, and that temperature is quantitatively
    the most important driver of changes in biomass burning over the
    past 21,000 yrs. Given that a similar relationship between climate
    drivers and fire emerges from analyses of the interannual variability
    in biomass burning shown by remote-sensing observations of month-by-month
    burnt area between 1996 and 2008, our results signal a serious cause
    for concern in the face of continuing global warming.
    BibTeX:
    @article{Daniau2012,
      author = {Daniau, A.-L. and Bartlein, P. J. and Harrison, S. P. and Prentice, I. C. and Brewer, S. and Friedlingstein, P. and Harrison-Prentice, T. I. and Inoue, J. and Izumi, K. and Marlon, J. R. and Mooney, S. and Power, M. J. and Stevenson, J. and Tinner, W. and Andric, M. and Atanassova, J. and Behling, H. and Black, M. and Blarquez, O. and Brown, K. J. and Carcaillet, C. and Colhoun, E. A. and Colombaroli, D. and Davis, B. a. S. and D'Costa, D. and Dodson, J. and Dupont, L. and Eshetu, Z. and Gavin, D. G. and Genries, A. and Haberle, S. and Hallett, D. J. and Hope, G. and Horn, S. P. and Kassa, T. G. and Katamura, F. and Kennedy, L. M. and Kershaw, P. and Krivonogov, S. and Long, C. and Magri, D. and Marinova, E. and McKenzie, G. M. and Moreno, P. I. and Moss, P. and Neumann, F. H. and Norstrom, E. and Paitre, C. and Rius, D. and Roberts, N. and Robinson, G. S. and Sasaki, N. and Scott, L. and Takahara, H. and Terwilliger, V. and Thevenon, F. and Turner, R. and Valsecchi, V. G. and Vanniere, B. and Walsh, M. and Williams, N. and Zhang, Y.},
      title = {Predictability of biomass burning in response to climate changes},
      journal = {Global Biogeochemical Cycles},
      year = {2012},
      volume = {26},
      doi = {http://doi.org/10.1029/2011GB004249}
    }
    					
    Gavin2012 Gavin, D.G. Stoltman, J.P. (Hrsg.) Biogeography 2012 21st Century Geography: A Reference Handbook , pp. 77-89   incollection
    BibTeX:
    @incollection{Gavin2012,
      author = {Gavin, D.G.},
      title = {Biogeography},
      booktitle = {21st Century Geography: A Reference Handbook},
      publisher = {SAGE Publications},
      year = {2012},
      pages = {77--89}
    }
    					
    Gill2012 Gill, J.L.; Blois, J.L.; Goring, S.; Marlon, J.R.; Bartlein, P.J.; Nicoll, K.; Scott, A.C. & Whitlock, C. Paleoecological changes at Lake Cuitzeo were not consistent with an extraterrestrial impact 2012 Proceedings of the National Academy of Sciences of the United States of America
    Vol. 109 (34) , pp. E2243-E2243  
    article north-america
    BibTeX:
    @article{Gill2012,
      author = {Gill, Jacquelyn L. and Blois, Jessica L. and Goring, Simon and Marlon, Jennifer R. and Bartlein, Patrick J. and Nicoll, Kathleen and Scott, Andrew C. and Whitlock, Cathy},
      title = {Paleoecological changes at Lake Cuitzeo were not consistent with an extraterrestrial impact},
      journal = {Proceedings of the National Academy of Sciences of the United States of America},
      year = {2012},
      volume = {109},
      number = {34},
      pages = {E2243--E2243},
      doi = {http://doi.org/10.1073/pnas.1206196109}
    }
    					
    Marlon2012 Marlon, J.R.; Bartlein, P.J.; Gavin, D.G.; Long, C.J.; Anderson, R.S.; Briles, C.E.; Brown, K.J.; Colombaroli, D.; Hallett, D.J.; Power, M.J.; Scharf, E.A. & Walsh, M.K. Long-term perspective on wildfires in the western USA 2012 Proceedings of the National Academy of Sciences of the United States of America
    Vol. 109 (9) , pp. E535-E543  
    article climate-change, colorado front range, historical fire regimes, klamath mountains, north-america, ponderosa pine forests, rocky-mountains, southern oscillation, southwestern united-states, spatial-patterns
    Abstract: Understanding the causes and consequences of wildfires in forests
    of the western United States requires integrated information about
    fire, climate changes, and human activity on multiple temporal scales.
    We use sedimentary charcoal accumulation rates to construct long-term
    variations in fire during the past 3,000 y in the American West and
    compare this record to independent fire-history data from historical
    records and fire scars. There has been a slight decline in burning
    over the past 3,000 y, with the lowest levels attained during the
    20th century and during the Little Ice Age (LIA, ca. 1400-1700
    CE [Common Era]). Prominent peaks in forest fires occurred during
    the Medieval Climate Anomaly (ca. 950-1250 CE) and during the 1800s.
    Analysis of climate reconstructions beginning from 500 CE and population
    data show that temperature and drought predict changes in biomass
    burning up to the late 1800s CE. Since the late 1800s, human activities
    and the ecological effects of recent high fire activity caused a
    large, abrupt decline in burning similar to the LIA fire decline.
    Consequently, there is now a forest "fire deficit" in the western
    United States attributable to the combined effects of human activities,
    ecological, and climate changes. Large fires in the late 20th and
    21st century fires have begun to address the fire deficit, but it
    is continuing to grow.
    BibTeX:
    @article{Marlon2012,
      author = {Marlon, Jennifer R. and Bartlein, Patrick J. and Gavin, Daniel G. and Long, Colin J. and Anderson, R. Scott and Briles, Christy E. and Brown, Kendrick J. and Colombaroli, Daniele and Hallett, Douglas J. and Power, Mitchell J. and Scharf, Elizabeth A. and Walsh, Megan K.},
      title = {Long-term perspective on wildfires in the western USA},
      journal = {Proceedings of the National Academy of Sciences of the United States of America},
      year = {2012},
      volume = {109},
      number = {9},
      pages = {E535--E543},
      doi = {http://doi.org/10.1073/pnas.1112839109}
    }
    					
    Oswald2012 Oswald, W.W.; Gavin, D.G.; Anderson, P.M.; Brubaker, L.B. & Hu, F.S. A 14,500-year record of landscape change from Okpilak Lake, northeastern Brooks Range, northern Alaska 2012 Journal of Paleolimnology
    Vol. 48 (1) , pp. 101-113  
    article arctic foothills, british-columbia, climate-change, glaciation, glacier, holocene, holocene glacier fluctuations, lake sediment, mountains, northwestern alaska, paleoecology, pollen, pollen records, river aggradation, sediments, tundra
    Abstract: Analyses of lithology, organic-matter content, magnetic susceptibility,
    and pollen in a sediment core from Okpilak Lake, located in the northeastern
    Brooks Range, provide new insights into the history of climate, landscape
    processes, and vegetation in northern Alaska since 14,500 cal year
    BP. The late-glacial interval (textgreater 11,600 cal year BP)
    featured sparse vegetation cover and the erosion of minerogenic sediment
    into the lake from nearby hillslopes, as evidenced by Cyperaceae-dominated
    pollen assemblages and high magnetic susceptibility (MS) values.
    Betula expanded in the early Holocene (11,600-8,500 cal year BP),
    reducing mass wasting on the landscape, as reflected by lower MS.
    Holocene sediments contain a series of silt- and clay-dominated layers,
    and given their physical characteristics and the topographic setting
    of the lake on the braided outwash plain of the Okpilak River, the
    inorganic layers are interpreted as rapidly deposited fluvial sediments,
    likely associated with intervals of river aggradation, changes in
    channel planform, and periodic overbank flow via a channel that connects
    the river and lake. The episodes of fluvial dynamics and aggradation
    appear to have been related to regional environmental variability,
    including a period of glacial retreat during the early Holocene,
    as well as glacial advances in the middle Holocene (5,500-5,200 cal
    year BP) and during the Little Ice Age (500-400 cal year BP).
    The rapid deposition of multiple inorganic layers during the early
    Holocene, including thick layers at 10,900-10,000 and 9,400-9,200
    cal year BP, suggests that it was a particularly dynamic interval
    of fluvial activity and landscape change.
    BibTeX:
    @article{Oswald2012,
      author = {Oswald, W. Wyatt and Gavin, Daniel G. and Anderson, Patricia M. and Brubaker, Linda B. and Hu, Feng Sheng},
      title = {A 14,500-year record of landscape change from Okpilak Lake, northeastern Brooks Range, northern Alaska},
      journal = {Journal of Paleolimnology},
      year = {2012},
      volume = {48},
      number = {1},
      pages = {101--113},
      doi = {http://doi.org/10.1007/s10933-012-9605-6}
    }
    					
    Tang2012 Tang, G. & Bartlein, P.J. Modifying a dynamic global vegetation model for simulating large spatial scale land surface water balances 2012 Hydrology and Earth System Sciences
    Vol. 16 (8) , pp. 2547-2565  
    article basin, climate-change, evapotranspiration, hydrological model, leaf-area index, parameter uncertainties, remote-sensing data, soil-moisture, temporal variability, united-states
    Abstract: Satellite-based data, such as vegetation type and fractional vegetation
    cover, are widely used in hydrologic models to prescribe the vegetation
    state in a study region. Dynamic global vegetation models (DGVM)
    simulate land surface hydrology. Incorporation of satellite-based
    data into a DGVM may enhance a model's ability to simulate land
    surface hydrology by reducing the task of model parameterization
    and providing distributed information on land characteristics. The
    objectives of this study are to (i) modify a DGVM for simulating
    land surface water balances; (ii) evaluate the modified model in
    simulating actual evapotranspiration (ET), soil moisture, and surface
    runoff at regional or watershed scales; and (iii) gain insight into
    the ability of both the original and modified model to simulate large
    spatial scale land surface hydrology. To achieve these objectives,
    we introduce the "LPJ-hydrology" (LH) model which incorporates
    satellite-based data into the Lund-Potsdam-Jena (LPJ) DGVM. To
    evaluate the model we ran LH using historical (1981-2006) climate
    data and satellite-based land covers at 2.5 arc-min grid cells for
    the conterminous US and for the entire world using coarser climate
    and land cover data. We evaluated the simulated ET, soil moisture,
    and surface runoff using a set of observed or simulated data at different
    spatial scales. Our results demonstrate that spatial patterns of
    LH-simulated annual ET and surface runoff are in accordance with
    previously published data for the US; LH-modeled monthly stream
    flow for 12 major rivers in the US was consistent with observed
    values respectively during the years 1981-2006 (R-2 textgreater
    0.46, p textless 0.01; Nash-Sutcliffe Coefficient textgreater
    0.52). The modeled mean annual discharges for 10 major rivers worldwide
    also agreed well (differences textless 15 with observed values
    for these rivers. Compared to a degree-day method for snowmelt computation,
    the addition of the solar radiation effect on snowmelt enabled LH
    to better simulate monthly stream flow in winter and early spring
    for rivers located at mid-to-high latitudes. In addition, LH-modeled
    monthly soil moisture for the state of Illinois (US) agreed well
    (R-2 = 0.79, p textless 0.01) with observed data for the years
    1984-2001. Overall, this study justifies both the feasibility of
    incorporating satellite-based land covers into a DGVM and the reliability
    of LH to simulate land-surface water balances. To better estimate
    surface/river runoff at mid-to-high latitudes, we recommended that
    LPJ-DGVM considers the effects of solar radiation on snowmelt.
    BibTeX:
    @article{Tang2012,
      author = {Tang, G. and Bartlein, P. J.},
      title = {Modifying a dynamic global vegetation model for simulating large spatial scale land surface water balances},
      journal = {Hydrology and Earth System Sciences},
      year = {2012},
      volume = {16},
      number = {8},
      pages = {2547--2565},
      doi = {http://doi.org/10.5194/hess-16-2547-2012}
    }
    					
    Thompson2012 Thompson, R.S.; Anderson, K.H.; Pelltier, R.T.; Strickland, L.E.; Bartlein, P.J. & Shafer, S.L. Quantitative estimation of climatic parameters from vegetation data in North America by the mutual climatic range technique 2012 Quaternary Science Reviews
    Vol. 51 , pp. 18-39  
    article coleopteran assemblages, fossil beetle assemblages, modern analog technique, mutual climatic range, north america, paleobotany, paleoclimate reconstruction, paleoclimatology, paleoecology, part, plant fossils, pleistocene, seasonal temperatures, space-time climate, surface climate, vegetation
    Abstract: The mutual climatic range (MCR) technique is perhaps the most widely
    used method for estimating past climatic parameters from fossil assemblages,
    largely because it can be conducted on a simple list of the taxa
    present in an assemblage. When applied to plant macrofossil data,
    this unweighted approach (MCRun) will frequently identify a large
    range for a given climatic parameter where the species in an assemblage
    can theoretically live together. To narrow this range, we devised
    a new weighted approach (MCRwt) that employs information from the
    modern relations between climatic parameters and plant distributions
    to lessen the influence of the "tails" of the distributions of the
    climatic data associated with the taxa in an assemblage. To assess
    the performance of the MCR approaches, we applied them to a set
    of modern climatic data and plant distributions on a 25-km grid for
    North America, and compared observed and estimated climatic values
    for each grid point. In general, MCRwt was superior to MCRun,
    in providing smaller anomalies, less bias, and better correlations
    between observed and estimated values. However, by the same measures,
    the results of Modern Analog Technique (MAT) approaches were superior
    to MCRwt. Although this might be reason to favor MAT approaches,
    they are based on assumptions that may not be valid for paleoclimatic
    reconstructions, including that: 1) the absence of a taxon from a
    fossil sample is meaningful, 2) plant associations were largely unaffected
    by past changes in either levels of atmospheric carbon dioxide or
    in the seasonal distributions of solar radiation, and 3) plant associations
    of the past are adequately represented on the modern landscape. To
    illustrate the application of these MCR and MAT approaches to
    paleoclimatic reconstructions, we applied them to a Pleistocene paleobotanical
    assemblage from the western United States. From our examinations
    of the estimates of modern and past climates from vegetation assemblages,
    we conclude that the MCRun technique provides reliable and unbiased
    estimates of the ranges of possible climatic conditions that can
    reasonably be associated with these assemblages. The application
    of MCRwt and MAT approaches can further constrain these estimates
    and may provide a systematic way to assess uncertainty. The data
    sets required for MCR analyses in North America are provided in
    a parallel publication. Published by Elsevier Ltd.
    BibTeX:
    @article{Thompson2012,
      author = {Thompson, R. S. and Anderson, K. H. and Pelltier, R. T. and Strickland, L. E. and Bartlein, P. J. and Shafer, S. L.},
      title = {Quantitative estimation of climatic parameters from vegetation data in North America by the mutual climatic range technique},
      journal = {Quaternary Science Reviews},
      year = {2012},
      volume = {51},
      pages = {18--39},
      doi = {http://doi.org/10.1016/j.quascirev.2012.07.003}
    }
    					
    Bartlein2011 Bartlein, P.J.; Harrison, S.P.; Brewer, S.; Connor, S.; Davis, B. a.S.; Gajewski, K.; Guiot, J.; Harrison-Prentice, T.I.; Henderson, A.; Peyron, O.; Prentice, I.C.; Scholze, M.; Seppa, H.; Shuman, B.; Sugita, S.; Thompson, R.S.; Viau, A.E.; Williams, J. & Wu, H. Pollen-based continental climate reconstructions at 6 and 21 ka: a global synthesis 2011 Climate Dynamics
    Vol. 37 (3-4) , pp. 775-802  
    article c-14 yr bp, climate model evaluation, eastern north-america, general-circulation model, lake status data, last glacial maximum, last glacial maximum, leaf-area index, mid-holocene, modern analog technique, palaeovegetation palaeoclimate reconstructions, past 21,000 years, plant functional types, plant macrofossils, pmip2 coupled simulations, pollen, reconstruction uncertainties
    Abstract: Subfossil pollen and plant macrofossil data derived from (14)C-dated
    sediment profiles can provide quantitative information on glacial
    and interglacial climates. The data allow climate variables related
    to growing-season warmth, winter cold, and plant-available moisture
    to be reconstructed. Continental-scale reconstructions have been
    made for the mid-Holocene (MH, around 6 ka) and Last Glacial Maximum
    (LGM, around 21 ka), allowing comparison with palaeoclimate simulations
    currently being carried out as part of the fifth Assessment Report
    (AR5) of the Intergovernmental Panel on Climate Change. The synthesis
    of the available MH and LGM climate reconstructions and their
    uncertainties, obtained using modern-analogue, regression and model-inversion
    techniques, is presented for four temperature variables and two moisture
    variables. Reconstructions of the same variables based on surface-pollen
    assemblages are shown to be accurate and unbiased. Reconstructed
    LGM and MH climate anomaly patterns are coherent, consistent
    between variables, and robust with respect to the choice of technique.
    They support a conceptual model of the controls of Late Quaternary
    climate change whereby the first-order effects of orbital variations
    and greenhouse forcing on the seasonal cycle of temperature are predictably
    modified by responses of the atmospheric circulation and surface
    energy balance.
    BibTeX:
    @article{Bartlein2011,
      author = {Bartlein, P. J. and Harrison, S. P. and Brewer, S. and Connor, S. and Davis, B. a. S. and Gajewski, K. and Guiot, J. and Harrison-Prentice, T. I. and Henderson, A. and Peyron, O. and Prentice, I. C. and Scholze, M. and Seppa, H. and Shuman, B. and Sugita, S. and Thompson, R. S. and Viau, A. E. and Williams, J. and Wu, H.},
      title = {Pollen-based continental climate reconstructions at 6 and 21 ka: a global synthesis},
      journal = {Climate Dynamics},
      year = {2011},
      volume = {37},
      number = {3-4},
      pages = {775--802},
      doi = {http://doi.org/10.1007/s00382-010-0904-1}
    }
    					
    Gavin2011 Gavin, D.G.; Henderson, A.C.G.; Westover, K.; Fritz, S.C.; Walker, I.R.; Leng, M.J. & Hu, F.S. Abrubt Holocene climate change and potential response to solar forcing in western Canada 2011 Quaternary Science Reviews , pp. -   article
    Abstract: Several abrupt climate events during the Holocene, including the widely
    documented oscillation at 8.2 thousand years before present (ka),
    are attributed to changes in the North Atlantic thermohaline circulation.
    Additional mechanisms, such as interactions between atmospheric circulation,
    ice-sheet dynamics, and the influence of solar irradiance, also have
    been proposed to explain abrupt climatic events, but evidence remains
    elusive. This study presents evidence from multi-proxy analyses on
    the Holocene sediments of Eleanor Lake, interior British Columbia.
    Climatic inferences from our decadal-resolution record of biogenic
    silica (BSi) abundance are supported by changes in diatom and pollen
    assemblages from the same core and correlations with existing regional
    climate records. The BSi record reveals abrupt and persistent climatic
    shifts at 10.2, 9.3, and 8.5 ka, the latter two of which are coeval
    with major collapses of the Laurentide Ice Sheet. The record also
    reveals a short-term cooling at 8.2 ka that is distinct from the
    8.5 ka event and similar in magnitude to several other late-Holocene
    coolings. BSi is correlated with solar-irradiance indices (r=0.43-0.61),
    but the correlation is opposite in sign to that expected from direct
    solar forcing and weakens after 8 ka. Possible mechanisms causing
    the abrupt and persistent climate changes of the early Holocene include
    1) sudden losses of ice and proglacial lake extent, causing a shift
    in the meridional structure of atmospheric circulation, 2) a possible
    link between solar minima and El Ni√Īo-like conditions that are correlated
    with warm spring temperature in interior British Columbia, and 3)
    the influence of solar irradiance variability on the position of
    the polar jet, possibly via effects on the strength of the glacial
    anticyclone.
    BibTeX:
    @article{Gavin2011,
      author = {Gavin, DG and Henderson, ACG and Westover, K and Fritz, SC and Walker, IR and Leng, MJ and Hu, FS},
      title = {Abrubt Holocene climate change and potential response to solar forcing in western Canada},
      journal = {Quaternary Science Reviews},
      year = {2011},
      pages = {--}
    }
    					
    Long2011 Long, C.J.; Power, M.J. & Bartlein, P.J. The effects of fire and tephra deposition on forest vegetation in the Central Cascades, Oregon 2011 Quaternary Research
    Vol. 75 (1) , pp. 151-158  
    article
    Abstract: High-resolution charcoal and pollen analyses were used to reconstruct
    a 12,000-yr-long fire and vegetation history of the Tumalo Lake watershed
    and to examine the short-term effects that tephra deposition have
    on forest composition and fire regime. The record suggests that,
    from 12,000 to 9200 cal yr BP, the watershed was dominated by an
    open Pinus forest with Artemisia as a common understory species.
    Fire episodes occurred on average every 115 yr. Beginning around
    9200 cal yr BP, and continuing to the present. Abies became more
    common while Artemisia declined, suggesting the development of a
    closed forest structure and a decrease in the frequency of fire episodes,
    occurring on average every 160 yr. High-resolution pollen analyses
    before and after the emplacement of three distinct tephra deposits
    in the watershed suggest that nonarboreal species were most affected
    by tephra events and that recovery of the vegetation community to
    previous conditions took between 40 and 100 yr. Changes in forest
    composition were not associated with tephra depositional events or
    changes in fire-episode frequency, implying that the regional climate
    is the more important control on long-term forest composition and
    structure of the vegetation in the Cascade Range. (C) 2010 University
    of Washington. Published by Elsevier Inc. All rights reserved.
    BibTeX:
    @article{Long2011,
      author = {Long, CJ and Power, MJ and Bartlein, PJ},
      title = {The effects of fire and tephra deposition on forest vegetation in the Central Cascades, Oregon},
      journal = {Quaternary Research},
      year = {2011},
      volume = {75},
      number = {1},
      pages = {151--158}
    }
    					
    Marcus2011 Marcus, W.A.; Rasmussen, J. & Fonstad, M.A. Response of the fluvial wood system to fire and floods in northern Yellowstone 2011 Annals of the Association of American Geographers
    Vol. 101 (1) , pp. 21-44  
    article fluvial geomorphology
    Abstract: We map the distribution of wood continuously along 73.4 km of second-
    through fifth-order streams in Yellowstone National Park and develop
    a Monte Carlo model of wood supply, transport, and storage to investigate:
    (1) spatial distributions of wood in burned and unburned basins,
    (2) associations between geomorphology and spatial distributions
    of wood, and (3) effects of flood timing and sequence on wood distributions.
    Wood counts in 2000 and 2001 vary by over two orders of magnitude
    over distances of several hundred meters. Qualitative models using
    catchment-scale characterizations of streams (e.g., whether a stream
    is third or fourth order) do not explain the degree of local variability.
    Reach-scale wood counts are weakly related to channel width in the
    extensively burned Cache Creek basin and to streamside forest cover
    and number of channel threads in all basins. Wood counts are not
    related to other reach-scale variations in channel morphology or
    fire effects. Monte Carlo simulations indicate that postfire flood
    timing and sequence drive variability in wood counts, with spatial
    variations in dominant processes and asynchronous timing of fire
    and floods creating a complex cascade of disturbance and a patchwork
    mosaic of wood. Existing descriptive models for postfire wood response
    do not predict this mosaic, although they capture the central tendency
    of variations. The central tendency is, however, a poor predictor
    of postdisturbance wood accumulations, so we develop a probabilistic
    model that better captures the range of potential postfire responses.
    We make recommendations for wood monitoring and management based
    on the empirical data and model results.
    BibTeX:
    @article{Marcus2011,
      author = {Marcus, WA and Rasmussen, J and Fonstad, MA},
      title = {Response of the fluvial wood system to fire and floods in northern Yellowstone},
      journal = {Annals of the Association of American Geographers},
      year = {2011},
      volume = {101},
      number = {1},
      pages = {21--44}
    }
    					
    McMahon2011 McMahon, S.M.; Harrison, S.P.; Armbruster, W.S.; Bartlein, P.J.; Beale, C.M.; Edwards, M.E.; Kattge, J.; Midgley, G.; Morin, X. & Prentice, I.C. Improving assessment and modelling of climate change impacts on global terrestrial biodiversity 2011 Trends in Ecology & Evolution
    Vol. 26 (5) , pp. 249-259  
    article distributions, ecosystem function, fire regimes, future, last glacial maximum, millennial-scale variability, niche, plant functional types, species range shifts, vegetation dynamics
    Abstract: Understanding how species and ecosystems respond to climate change
    has become a major focus of ecology and conservation biology. Modelling
    approaches provide important tools for making future projections,
    but current models of the climate-biosphere interface remain overly
    simplistic, undermining the credibility of projections. We identify
    five ways in which substantial advances could be made in the next
    few years: (i) improving the accessibility and efficiency of biodiversity
    monitoring data, Oil quantifying the main determinants of the sensitivity
    of species to climate change, (Hi) incorporating community dynamics
    into projections of biodiversity responses, (iv) accounting for the
    influence of evolutionary processes on the response of species to
    climate change, and (v) improving the biophysical rule sets that
    define functional groupings of species in global models.
    BibTeX:
    @article{McMahon2011,
      author = {McMahon, Sean M. and Harrison, Sandy P. and Armbruster, W. Scott and Bartlein, Patrick J. and Beale, Colin M. and Edwards, Mary E. and Kattge, Jens and Midgley, Guy and Morin, Xavier and Prentice, I. Colin},
      title = {Improving assessment and modelling of climate change impacts on global terrestrial biodiversity},
      journal = {Trends in Ecology & Evolution},
      year = {2011},
      volume = {26},
      number = {5},
      pages = {249--259},
      doi = {http://doi.org/10.1016/j.tree.2011.02.012}
    }
    					
    Mooney2011 Mooney, S.D.; Harrison, S.P.; Bartlein, P.J.; Daniau, A.L.; Stevenson, J.; Brownlie, K.C.; Buckman, S.; Cupper, M.; Luly, J.; Black, M.; Colhoun, E.; D'Costa, D.; Dodson, J.; Haberle, S.; Hope, G.S.; Kershaw, P.; Kenyon, C.; McKenzie, M. & Williams, N. Late Quaternary fire regimes of Australasia 2011 Quaternary Science Reviews
    Vol. 30 (1-2) , pp. 28-46  
    article fire: paleo and modern
    Abstract: We have compiled 223 sedimentary charcoal records from Australasia
    in order to examine the temporal and spatial variability of fire
    regimes during the Late Quaternary. While some of these records cover
    more than a full glacial cycle, here we focus on the last 70,000
    years when the number of individual records in the compilation allows
    more robust conclusions. On orbital time scales, fire in Australasia
    predominantly reflects climate, with colder periods characterized
    by less and warmer intervals by more biomass burning. The composite
    record for the region also shows considerable millennial-scale variability
    during the last glacial interval (73.5-14.7 ka). Within the limits
    of the dating uncertainties of individual records, the variability
    shown by the composite charcoal record is more similar to the form,
    number and timing of Dansgaard-Oeschger cycles as observed in Greenland
    ice cores than to the variability expressed in the Antarctic ice-core
    record. The composite charcoal record suggests increased biomass
    burning in the Australasian region during Greenland Interstadials
    and reduced burning during Greenland Stadials. Millennial-scale variability
    is characteristic of the composite record of the subtropical high
    pressure belt during the past 21 ka, but the tropics show a somewhat
    simpler pattern of variability with major peaks in biomass burning
    around 15 ka and 8 ka. There is no distinct change in fire regime
    corresponding to the arrival of humans in Australia at 50 +/- 10
    ka and no correlation between archaeological evidence of increased
    human activity during the past 40 ka and the history of biomass burning.
    However, changes in biomass burning in the last 200 years may have
    been exacerbated or influenced by humans. (C) 2010 Elsevier Ltd.
    All rights reserved.
    BibTeX:
    @article{Mooney2011,
      author = {Mooney, SD and Harrison, SP and Bartlein, PJ and Daniau, AL and Stevenson, J and Brownlie, KC and Buckman, S and Cupper, M and Luly, J and Black, M and Colhoun, E and D'Costa, D and Dodson, J and Haberle, S and Hope, GS and Kershaw, P and Kenyon, C and McKenzie, M and Williams, N},
      title = {Late Quaternary fire regimes of Australasia},
      journal = {Quaternary Science Reviews},
      year = {2011},
      volume = {30},
      number = {1-2},
      pages = {28--46}
    }
    					
    Power2011 Power, M.J.; Whitlock, C. & Bartlein, P.J. Postglacial fire, vegetation, and climate history across an elevational gradient in the Northern Rocky Mountains, USA and Canada 2011 Quaternary Science Reviews
    Vol. 30 (19-20) , pp. 2520-2533  
    article biomass burning, british-columbia, charcoal, forests, holocene, holocene climate, instability, lake-level, montana, pollen, range, rocky mountains, variability, yellowstone-national-park
    Abstract: A 13,100-year-long high-resolution pollen and charcoal record from
    Foy Lake in western Montana is compared with a network of vegetation
    and fire-history records from the Northern Rocky Mountains. New and
    previously published results were stratified by elevation into upper
    and lower and tree line to explore the role of Holocene climate variability
    on vegetation dynamics and fire regimes. During the cooler and drier
    Lateglacial period, ca 13,000 cal yr BP, sparsely vegetated Picea
    parkland occupied Foy Lake as well as other low- and high-elevations
    with a low incidence of fire. During the warmer early Holocene, from
    ca 11,000-7500 cal yr BP, low-elevation records, including Foy,
    indicate significant restructuring of regional vegetation as Lateglacial
    Picea parkland gave way to a mixed forest of Pinus-Pseudotsuga-Larix.
    In contrast, upper tree line sites (ca textgreater2000 m) supported
    Pinus albicaulis and/or P. monticola-Abies-Picea forests in the Lateglacial
    and early Holocene. Regionally, biomass burning gradually increased
    from the Lateglacial times through the middle Holocene. However,
    upper tree line fire-history records suggest several climate-driven
    decreases in biomass burning centered at 11,500, 8500, 4000, 1600
    and 500 cal yr BP. In contrast, lower tree line records generally
    experienced a gradual increase in biomass burning from the Lateglacial
    to ca 8000 cal yr BP, then reduced fire activity until a late Holocene
    maximum at 1800 cal yr BP, as structurally complex mesophytic forests
    at Foy Lake and other sites supported mixed-severity fire regimes.
    During the last two millennia, fire activity decreased at low elevations
    as modern forests developed and the climate became cooler and wetter
    than before. Embedded within these long-term trends are high amplitude
    variations in both vegetation dynamics and biomass burning. High-elevation
    paleoecological reconstructions tend to be more responsive to long-term
    changes in climate forcing related to growing-season temperature.
    Low-elevation records in the NRM have responded more abruptly to
    changes in effective precipitation during the late Holocene. Prolonged
    droughts, including those between 1200 and 800 cal yr BP, and climatic
    cooling during the last few centuries continues to influence vegetation
    and fire regimes at low elevation while increasing temperature has
    increased biomass burning in high elevations. Published by Elsevier
    Ltd.
    BibTeX:
    @article{Power2011,
      author = {Power, M. J. and Whitlock, C. and Bartlein, P. J.},
      title = {Postglacial fire, vegetation, and climate history across an elevational gradient in the Northern Rocky Mountains, USA and Canada},
      journal = {Quaternary Science Reviews},
      year = {2011},
      volume = {30},
      number = {19-20},
      pages = {2520--2533},
      doi = {http://doi.org/10.1016/j.quascirev.2011.04.012}
    }
    					
    Prentice2011 Prentice, I.C.; Harrison, S.P. & Bartlein, P.J. Global vegetation and terrestrial carbon cycle changes after the last ice age 2011 New Phytologist
    Vol. 189 (4) , pp. 988-998  
    article
    Abstract: In current models, the ecophysiological effects of CO2 create both
    woody thickening and terrestrial carbon uptake, as observed now,
    and forest cover and terrestrial carbon storage increases that took
    place after the last glacial maximum (LGM). Here, we aimed to assess
    the realism of modelled vegetation and carbon storage changes between
    LGM and the pre-industrial Holocene (PIH). We applied Land Processes
    and eXchanges (LPX), a dynamic global vegetation model (DGVM), with
    lowered CO2 and LGM climate anomalies from the Palaeoclimate Modelling
    Intercomparison Project (PMIP II), and compared the model results
    with palaeodata. Modelled global gross primary production was reduced
    by 27-36% and carbon storage by 550-694 Pg C compared with PIH. Comparable
    reductions have been estimated from stable isotopes. The modelled
    areal reduction of forests is broadly consistent with pollen records.
    Despite reduced productivity and biomass, tropical forests accounted
    for a greater proportion of modelled land carbon storage at LGM (28-32%)
    than at PIH (25%). The agreement between palaeodata and model results
    for LGM is consistent with the hypothesis that the ecophysiological
    effects of CO2 influence tree-grass competition and vegetation productivity,
    and suggests that these effects are also at work today.
    BibTeX:
    @article{Prentice2011,
      author = {Prentice, IC and Harrison, SP and Bartlein, PJ},
      title = {Global vegetation and terrestrial carbon cycle changes after the last ice age},
      journal = {New Phytologist},
      year = {2011},
      volume = {189},
      number = {4},
      pages = {988--998}
    }
    					
    Prentice2011a Prentice, I.C.; Kelley, D.I.; Foster, P.N.; Friedlingstein, P.; Harrison, S.P. & Bartlein, P.J. Modeling fire and the terrestrial carbon balance 2011 Global Biogeochemical Cycles
    Vol. 25  
    article 20th-century, atmospheric co2, biomass, climate-change, emissions, forest-fires, global vegetation model, interannual variability, land, wildfire activity
    Abstract: Four CO2 concentration inversions and the Global Fire Emissions
    Database (GFED) versions 2.1 and 3 are used to provide benchmarks
    for climate-driven modeling of the global land-atmosphere CO2 flux
    and the contribution of wildfire to this flux. The Land surface Processes
    and exchanges (LPX) model is introduced. LPX is based on the
    Lund-Potsdam-Jena Spread and Intensity of FIRE (LPJ-SPITFIRE)
    model with amended fire probability calculations. LPX omits human
    ignition sources yet simulates many aspects of global fire adequately.
    It captures the major features of observed geographic pattern in
    burnt area and its seasonal timing and the unimodal relationship
    of burnt area to precipitation. It simulates features of geographic
    variation in the sign of the interannual correlations of burnt area
    with antecedent dryness and precipitation. It simulates well the
    interannual variability of the global total land-atmosphere CO2
    flux. There are differences among the global burnt area time series
    from GFED2.1, GFED3 and LPX, but some features are common to
    all. GFED3 fire CO2 fluxes account for only about 1/3 of the
    variation in total CO2 flux during 1997-2005. This relationship
    appears to be dominated by the strong climatic dependence of deforestation
    fires. The relationship of LPX-modeled fire CO2 fluxes to total
    CO2 fluxes is weak. Observed and modeled total CO2 fluxes track
    the El Nino-Southern Oscillation (ENSO) closely; GFED3 burnt
    area and global fire CO2 flux track the ENSO much less so. The
    GFED3 fire CO2 flux-ENSO connection is most prominent for the
    El Nino of 1997-1998, which produced exceptional burning conditions
    in several regions, especially equatorial Asia. The sign of the observed
    relationship between ENSO and fire varies regionally, and LPX
    captures the broad features of this variation. These complexities
    underscore the need for process-based modeling to assess the consequences
    of global change for fire and its implications for the carbon cycle.
    BibTeX:
    @article{Prentice2011a,
      author = {Prentice, I. C. and Kelley, D. I. and Foster, P. N. and Friedlingstein, P. and Harrison, S. P. and Bartlein, P. J.},
      title = {Modeling fire and the terrestrial carbon balance},
      journal = {Global Biogeochemical Cycles},
      year = {2011},
      volume = {25},
      doi = {http://doi.org/10.1029/2010GB003906}
    }
    					
    Schmittner2011 Schmittner, A.; Urban, N.M.; Shakun, J.D.; Mahowald, N.M.; Clark, P.U.; Bartlein, P.J.; Mix, A.C. & Rosell-Mele, A. Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum 2011 Science
    Vol. 334 (6061) , pp. 1385-1388  
    article co2, constraints, earth, future, model
    Abstract: Assessing the impact of future anthropogenic carbon emissions is currently
    impeded by uncertainties in our knowledge of equilibrium climate
    sensitivity to atmospheric carbon dioxide doubling. Previous studies
    suggest 3 kelvin (K) as the best estimate, 2 to 4.5 K as the 66br> probability range, and nonzero probabilities for much higher values,
    the latter implying a small chance of high-impact climate changes
    that would be difficult to avoid. Here, combining extensive sea and
    land surface temperature reconstructions from the Last Glacial Maximum
    with climate model simulations, we estimate a lower median (2.3 K)
    and reduced uncertainty (1.7 to 2.6 K as the 66% probability range,
    which can be widened using alternate assumptions or data subsets).
    Assuming that paleoclimatic constraints apply to the future, as predicted
    by our model, these results imply a lower probability of imminent
    extreme climatic change than previously thought.
    BibTeX:
    @article{Schmittner2011,
      author = {Schmittner, Andreas and Urban, Nathan M. and Shakun, Jeremy D. and Mahowald, Natalie M. and Clark, Peter U. and Bartlein, Patrick J. and Mix, Alan C. and Rosell-Mele, Antoni},
      title = {Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum},
      journal = {Science},
      year = {2011},
      volume = {334},
      number = {6061},
      pages = {1385--1388},
      doi = {http://doi.org/10.1126/science.1203513}
    }
    					
    Vanniere2011 Vanniere, B.; Power, M.J.; Roberts, N.; Tinner, W.; Carrion, J.; Magny, M.; Bartlein, P.; Colombaroli, D.; Daniau, A.L.; Finsinger, W.; Gil-Romera, G.; Kaltenrieder, P.; Pini, R.; Sadori, L.; Turner, R.; Valsecchi, V. & Vescovi, E. Circum-Mediterranean fire activity and climate changes during the mid-Holocene environmental transition (8500-2500 cal. BP) 2011 Holocene
    Vol. 21 (1) , pp. 53-73  
    article
    Abstract: A mid- to late-Holocene synthesis of fire activity from the Mediterranean
    basin explores the linkages among fire, climate variability and seasonality
    through several climatic and ecological transitions. Regional fire
    histories were created from 36 radiocarbon-dated sedimentary charcoal
    records, available from the Global Charcoal Database. During the
    mid-Holocene 'Thermal Maximum' around 7500-4500 cal. BP, charcoal
    records from the northern Mediterranean suggest an increase in fire
    while records from the southern Mediterranean indicate a decrease
    associated with wetter-than-present summers. A North-South partition
    between 40 degrees and 43 degrees N latitude is apparent in the central
    and western Mediterranean. Relatively abrupt changes in fire activity
    are observed c. 5500-5000 cal. BP. Records of Holocene fire activity
    appear sensitive to both orbitally forced climate changes and shorter-lived
    excursions which may be related to North Atlantic cold events, possibly
    modulated by an NAO-like climate mechanism. In cases where human-fire
    interactions have been documented, the regional coherency between
    fire occurrence and climate forcing suggests a dominant fire-climate
    relationship during the early-mid Holocene. The human influence on
    regional fire activity became increasingly important after c. 4000-3000
    cal. BP. Results also suggest that: (1) teleconnections between the
    Mediterranean area and other climatic regions, in particular the
    North Atlantic and the low latitudes monsoon areas, influenced past
    fire activity; (2) gradual forcing, such as changes in orbital parameters,
    may have triggered abrupt shifts in fire activity; (3) regional fire
    reconstructions contradict former notions of a gradual (mid-to late-Holocene)
    aridification of the entire region due to climate and/or human activities
    and the importance of shorter-term events; (4) Mediterranean fire
    activity appears hightly sensitive to climate dynamics and thus could
    be considerably impacted by future climate changes.
    BibTeX:
    @article{Vanniere2011,
      author = {Vanniere, B and Power, MJ and Roberts, N and Tinner, W and Carrion, J and Magny, M and Bartlein, P and Colombaroli, D and Daniau, AL and Finsinger, W and Gil-Romera, G and Kaltenrieder, P and Pini, R and Sadori, L and Turner, R and Valsecchi, V and Vescovi, E},
      title = {Circum-Mediterranean fire activity and climate changes during the mid-Holocene environmental transition (8500-2500 cal. BP)},
      journal = {Holocene},
      year = {2011},
      volume = {21},
      number = {1},
      pages = {53--73}
    }
    					
    Walther2011 Walther, S.C.; Marcus, W.A. & Fonstad, M.A. Evaluation of high-resolution, true-colour, aerial imagery for mapping bathymetry in a clear-water river without ground-based depth measurements 2011 International Journal of Remote Sensing
    Vol. 32 (15) , pp. 4343-4363  
    article airborne multispectral imagery, gravel-bed rivers, in-stream habitats, morphology, mountain streams
    Abstract: This study evaluates the potential of the hydraulically assisted bathymetry
    (HAB-2) model coupled with true-colour, three-band, aerial imagery
    to map bathymetry in the clear-water McKenzie River, Oregon, USA,
    in the absence of ground-based depth measurements. It is the most
    rigorous test of the HAB-2 model to date. Correlation-coefficient
    (r(2)) values for sonar depths versus modelled depths are 0.40 for
    2007, 10 cm resolution imagery. Overall depth trends follow those
    of sonar data, except in areas where there are shadows, riffles or
    obstructions that block the view of the river (e. g. overhanging
    trees, bridges). Low-pass filtering of the image to remove film granularity
    does little to improve the results, although an Olympic filter improves
    the r(2) value from 0.40 to 0.48. The moderate fit of the model results
    to sonar data in 2007 may also result from the 28-39 day gap between
    sonar and image acquisition, during which time, the discharge changed.
    HAB-2 depth estimates for the 2008 0.5 m imagery fit the depth
    measurements more closely (r(2) 0.89). The better fit may reflect
    the collection of ground and image data at approximately the same
    time and discharge, as well as coarser spatial resolution, which
    created less sensitivity to changes in substrate size and colour.
    The results suggest that the best depth-estimate results for the
    HAB-2 model are for depths ranging from 0.25 and 1.5 m. Use of
    digital imagery collected with digital cameras should also improve
    accuracies. Results indicate that the HAB-2 is useful for characterizing
    the approximate depths throughout the river channel if one avoids
    shadows, riffles and obstructions.
    BibTeX:
    @article{Walther2011,
      author = {Walther, Suzanne C. and Marcus, W. Andrew and Fonstad, Mark A.},
      title = {Evaluation of high-resolution, true-colour, aerial imagery for mapping bathymetry in a clear-water river without ground-based depth measurements},
      journal = {International Journal of Remote Sensing},
      year = {2011},
      volume = {32},
      number = {15},
      pages = {4343--4363},
      doi = {http://doi.org/10.1080/01431161.2010.486418}
    }
    					
    Arneth2010 Arneth, A.; Harrison, S.P.; Zaehle, S.; Tsigaridis, K.; Menon, S.; Bartlein, P.J.; Feichter, J.; Korhola, A.; Kulmala, M.; O'Donnell, D.; Schurgers, G.; Sorvari, S. & Vesala, T. Terrestrial biogeochemical feedbacks in the climate system 2010 Nature Geoscience
    Vol. 3 (8) , pp. 525-532  
    article
    Abstract: The terrestrial biosphere is a key regulator of atmospheric chemistry
    and climate. During past periods of climate change, vegetation cover
    and interactions between the terrestrial biosphere and atmosphere
    changed within decades. Modern observations show a similar responsiveness
    of terrestrial biogeochemistry to anthropogenically forced climate
    change and air pollution. Although interactions between the carbon
    cycle and climate have been a central focus, other biogeochemical
    feedbacks could be as important in modulating future climate change.
    Total positive radiative forcings resulting from feedbacks between
    the terrestrial biosphere and the atmosphere are estimated to reach
    up to 0.9 or 1.5 W m(-2) K-1 towards the end of the twenty-first
    century, depending on the extent to which interactions with the nitrogen
    cycle stimulate or limit carbon sequestration. This substantially
    reduces and potentially even eliminates the cooling effect owing
    to carbon dioxide fertilization of the terrestrial biota. The overall
    magnitude of the biogeochemical feedbacks could potentially be similar
    to that of feedbacks in the physical climate system, but there are
    large uncertainties in the magnitude of individual estimates and
    in accounting for synergies between these effects.
    BibTeX:
    @article{Arneth2010,
      author = {Arneth, A and Harrison, SP and Zaehle, S and Tsigaridis, K and Menon, S and Bartlein, PJ and Feichter, J and Korhola, A and Kulmala, M and O'Donnell, D and Schurgers, G and Sorvari, S and Vesala, T},
      title = {Terrestrial biogeochemical feedbacks in the climate system},
      journal = {Nature Geoscience},
      year = {2010},
      volume = {3},
      number = {8},
      pages = {525--532}
    }
    					
    Bartlein2010 Bartlein, P.J.; Harrison, S.P.; Brewer, S.; Connor, S.; Davis, B.A.S.; Gajewski, K.; Guiot, J.; Harrison-Prentice, T.I.; Henderson, A.; Peyron, O.; Prentice, I.C.; Scholze, M.; Seppä, H.; Shuman, B.; Sugita, S.; Thompson, R.S.; Viau, A.E.; Williams, J. & Wu, H. Pollen-based continental climate reconstructions at 6 and 21 ka: a global synthesis 2010 Climate Dynamics
    Vol. 37 , pp. 775-802  
    article
    BibTeX:
    @article{Bartlein2010,
      author = {Bartlein, P. J. and Harrison, S. P. and Brewer, S. and Connor, S. and Davis, B. A. S. and Gajewski, K. and Guiot, J. and Harrison-Prentice, T. I. and Henderson, A. and Peyron, O. and Prentice, I. C. and Scholze, M. and Seppä, H. and Shuman, B. and Sugita, S. and Thompson, R. S. and Viau, A. E. and Williams, J. and Wu, H.},
      title = {Pollen-based continental climate reconstructions at 6 and 21 ka: a global synthesis},
      journal = {Climate Dynamics},
      year = {2010},
      volume = {37},
      pages = {775--802},
      url = {http://www.springerlink.com/content/2762k2451307l623/supplementals/},
      doi = {http://doi.org/10.1007/s00382-010-0904-1}
    }
    					
    Colombaroli2010 Colombaroli, D. & Gavin, D.G. Highly episodic fire and erosion regime over the past 2,000 y in the Siskiyou Mountains, Oregon 2010 Proceedings of the National Academy of Sciences of the USA
    Vol. 107 (44) , pp. 18909-18914  
    article
    Abstract: Fire is a primary mode of natural disturbance in the forests of the
    Pacific Northwest. Increased fuel loads following fire suppression
    and the occurrence of several large and severe fires have led to
    the perception that in many areas there is a greatly increased risk
    of high-severity fire compared with presettlement forests. To reconstruct
    the variability of the fire regime in the Siskiyou Mountains, Oregon,
    we analyzed a 10-m, 2,000-y sediment core for charcoal, pollen, and
    sedimentological data. The record reveals a highly episodic pattern
    of fire in which 77% of the 68 charcoal peaks before Euro-American
    settlement cluster within nine distinct periods marked by a 15-y
    mean interval. The 11 largest charcoal peaks are significantly related
    to decadal-scale drought periods and are followed by pulses of minerogenic
    sediment suggestive of rapid sediment delivery. After logging in
    the 1950s, sediment load was increased fourfold compared with that
    from the most severe presettlement fire. Less severe fires, marked
    by smaller charcoal peaks and no sediment pulses, are not correlated
    significantly with drought periods. Pollen indicators of closed forests
    are consistent with fire-free periods of sufficient length to maintain
    dense forest and indicate a fire-triggered switch to more open conditions
    during the Medieval Climatic Anomaly. Our results indicate that over
    millennia fire was more episodic than revealed by nearby shorter
    tree-ring records and that recent severe fires have precedents during
    earlier drought episodes but also that sediment loads resulting from
    logging and road building have no precedent in earlier fire events.
    BibTeX:
    @article{Colombaroli2010,
      author = {Colombaroli, D and Gavin, DG},
      title = {Highly episodic fire and erosion regime over the past 2,000 y in the Siskiyou Mountains, Oregon},
      journal = {Proceedings of the National Academy of Sciences of the USA},
      year = {2010},
      volume = {107},
      number = {44},
      pages = {18909--18914}
    }
    					
    Daniau2010 Daniau, A.L.; Harrison, S.P. & Bartlein, P.J. Fire regimes during the Last Glacial 2010 Quaternary Science Reviews
    Vol. 29 (21-22) , pp. 2918-2930  
    article
    Abstract: Sedimentary charcoal records document changes in fire regime. We have
    identified 67 sites (30 sites with better than millennial resolution)
    which have records for some part of the Last Glacial to analyse changes
    in global fire regimes. Fire was consistently lower during the glacial
    than during the Eemian and Holocene. Within the glacial, Marine Isotope
    Stage (MIS) 3 is characterised globally by more fire than MIS 2.
    The signal for MIS 4 is less clear: there is more fire in the Northern
    Hemisphere and less fire in the Southern Hemisphere than during MIS
    2 and 3. The records, most particularly records from the northern
    extratropics, show millennial-scale variability in fire regimes corresponding
    to the rapid climate changes associated with Dansgaard-Oeschger (D-O)
    cycles. Most of the D-O cycles during the Last Glacial and all of
    the Heinrich stadials are apparent in the composite global record
    of fire regime: fire increases during D-O warming events and decreases
    during intervals of rapid cooling. Our analyses show that fire regimes
    show a lagged response to rapid climate changes of ca 100-200 years
    in the case of D-O warming events, ca 0-100 years in the case of
    D-O cooling events and ca 200 years in the case of Heinrich Stadials.
    The Strong climatic variability experienced during the glacial resulted
    in important changes in fire regimes even though the base level of
    biomass burning was less than today. (C) 2009 Elsevier Ltd. All rights
    reserved.
    BibTeX:
    @article{Daniau2010,
      author = {Daniau, AL and Harrison, SP and Bartlein, PJ},
      title = {Fire regimes during the Last Glacial},
      journal = {Quaternary Science Reviews},
      year = {2010},
      volume = {29},
      number = {21-22},
      pages = {2918--2930}
    }
    					
    Deligne2010 Deligne, N.I.; Cashman, K.V.; Gavin, D.G. & Roering, J.J. Reforestation of Collier Cone lava flow, central Oregon Cascades 2010 Geochimica et Cosmochimica Acta
    Vol. 74 (12) , pp. A221-A221-A221-A221  
    conference
    BibTeX:
    @conference{Deligne2010,
      author = {Deligne, NI and Cashman, KV and Gavin, DG and Roering, JJ},
      title = {Reforestation of Collier Cone lava flow, central Oregon Cascades},
      journal = {Geochimica et Cosmochimica Acta},
      year = {2010},
      volume = {74},
      number = {12},
      pages = {A221-A221--A221-A221}
    }
    					
    Fonstad2010 Fonstad, M.A. & Marcus, W.A. High resolution, basin extent observations and implications for understanding river form and process 2010 Earth Surface Processes and Landforms
    Vol. 35 (6) , pp. 680-698  
    article remote sensing fluvial geomorphology
    Abstract: Fifty years of fluvial studies have posited a variety of conceptual
    frameworks for characterizing river forms and processes throughout
    entire basins, including hydraulic geometry, the river continuum
    concept, self-organized criticality, and sediment links. This article
    uses basin-extent, high resolution observations of fluvial forms
    in the Nueces River basin, Texas, and Yellowstone National Park to
    evaluate the ability of these frameworks to characterize system behavior
    across a multitude of scales. The Nueces data were collected with
    remote sensing methods and the Yellowstone data were collected through
    extensive field surveys. The data resolution, spatial extent, and
    quality of these data sets allow direct comparison between the two
    areas. The 'hyperscale' comparison supports using of each these frameworks
    at specific scales, but also indicates an irreducible amount of variation
    in both datasets across many different scales that is not captured
    by the conceptual frameworks. Moreover, the scales and locations
    where one framework, such as hydraulic geometry, works well are often
    not the same scales and locations where another framework, such as
    the river continuum concept, works well. Because the conceptual frameworks
    appear to operate at scales and locations distinct from one another,
    the measurement approaches necessary to observe them must also be
    at different scales and locations. For example, 'seeing' self-organized
    criticality in a river system is difficult without an extensive survey
    through space, whereas the recognition of sediment links requires
    quite intense sampling in specific river regions. We suggest that
    these separations between measurement scales represent an incommensurability
    issue in river studies, making it very difficult to both communicate
    among and test between two or more competing theories. Making simultaneous
    hyperscale observations of the river is one approach to minimizing
    the theory-ladeness of observation, as deviations from different
    predictions can be plotted at every scale. Copyright (C) 2010 John
    Wiley & Sons, Ltd.
    BibTeX:
    @article{Fonstad2010,
      author = {Fonstad, MA and Marcus, WA},
      title = {High resolution, basin extent observations and implications for understanding river form and process},
      journal = {Earth Surface Processes and Landforms},
      year = {2010},
      volume = {35},
      number = {6},
      pages = {680--698}
    }
    					
    Higuera2010 Higuera, P.E.; Gavin, D.G.; Bartlein, P.J. & Hallett, D.J. Peak detection in sediment-charcoal records: impacts of alternative data analysis methods on fire-history interpretations 2010 International Journal of Wildland Fire
    Vol. 19 (8) , pp. 996-1014  
    article
    Abstract: Over the past several decades, high-resolution sediment-charcoal records
    have been increasingly used to reconstruct local fire history. Data
    analysis methods usually involve a decomposition that detrends a
    charcoal series and then applies a threshold value to isolate individual
    peaks, which are interpreted as fire episodes. Despite the proliferation
    of these studies, methods have evolved largely in the absence of
    a thorough statistical framework. We describe eight alternative decomposition
    models (four detrending methods used with two threshold-determination
    methods) and evaluate their sensitivity to a set of known parameters
    integrated into simulated charcoal records. Results indicate that
    the combination of a globally defined threshold with specific detrending
    methods can produce strongly biased results, depending on whether
    or not variance in a charcoal record is stationary through time.
    These biases are largely eliminated by using a locally defined threshold,
    which adapts to changes in variability throughout a charcoal record.
    Applying the alternative decomposition methods on three previously
    published charcoal records largely supports our conclusions from
    simulated records. We also present a minimum-count test for empirical
    records, which reduces the likelihood of false positives when charcoal
    counts are low. We conclude by discussing how to evaluate when peak
    detection methods are warranted with a given sediment-charcoal record.
    BibTeX:
    @article{Higuera2010,
      author = {Higuera, PE and Gavin, DG and Bartlein, PJ and Hallett, DJ},
      title = {Peak detection in sediment-charcoal records: impacts of alternative data analysis methods on fire-history interpretations},
      journal = {International Journal of Wildland Fire},
      year = {2010},
      volume = {19},
      number = {8},
      pages = {996--1014}
    }
    					
    Lamb2010 Lamb, M.P. & Fonstad, M.A. Rapid formation of a modern bedrock canyon by a single flood event 2010 Nature Geoscience
    Vol. 3 (7) , pp. 477-481  
    article abrasion, earth, erosion, gravel, incision, mars
    Abstract: Deep river canyons are thought to form slowly over geological time
    (see, for example, ref. 1), cut by moderate flows that reoccur every
    few years(2,3). In contrast, some of the most spectacular canyons
    on Earth and Mars were probably carved rapidly during ancient megaflood
    events(4-12). Quantification of the flood discharge, duration and
    erosion mechanics that operated during such events is hampered because
    we lack modern analogues. Canyon Lake Gorge, Texas, was carved in
    2002 during a single catastrophic flood(13). The event offers a rare
    opportunity to analyse canyon formation and test palaeohydraulic-reconstruction
    techniques under known topographic and hydraulic conditions. Here
    we use digital topographic models and visible/near-infrared aerial
    images from before and after the flood, discharge measured during
    the event, field measurements and sediment-transport modelling to
    show that the flood moved metre-sized boulders, excavated similar
    to 7 m of limestone and transformed a soil-mantled valley into a
    bedrock canyon in just similar to 3 days. We find that canyon morphology
    is strongly dependent on rock type: plucking of limestone blocks
    produced waterfalls, inner channels and bedrock strath terraces,
    whereas abrasion of cemented alluvium sculpted walls, plunge pools
    and streamlined islands. Canyon formation was so rapid that erosion
    might have been limited by the ability of the flow to transport sediment.
    We suggest that our results might improve hydraulic reconstructions
    of similar megafloods on Earth and Mars.
    BibTeX:
    @article{Lamb2010,
      author = {Lamb, Michael P. and Fonstad, Mark A.},
      title = {Rapid formation of a modern bedrock canyon by a single flood event},
      journal = {Nature Geoscience},
      year = {2010},
      volume = {3},
      number = {7},
      pages = {477--481},
      doi = {http://doi.org/10.1038/NGEO894}
    }
    					
    Marcus2010 Marcus, W.A. & Fonstad, M.A. Remote sensing of rivers: the emergence of a subdiscipline in the river sciences 2010 Earth Surface Processes and Landforms
    Vol. 35 (15) , pp. 1867-1872  
    article
    Abstract: This article reports on the special issue of Earth Surface Processes
    and Landforms dedicated to remote sensing of rivers. This emerging
    subdiscipline of river science has grown at a rapid rate in recent
    years because of: (a) the growing desire and need for data to document
    and explore the full range of spatial and temporal variations in
    river systems; (b) evolving technologies that enable lower cost data
    acquisition, processing and analysis at reach to catchment to continental
    scales; and (c) the increasing engagement of river scientists with
    GIScience. The convergence of these factors and the ever growing
    number of practitioners speaks to the need for more communication
    among researchers, a major reason for creating this special issue.
    The 12 articles in the volume cover a broad spectrum of applications
    that use a variety of platforms and sensors, ranging from photogrammetric
    mapping of riffle-pool morphology beneath forest canopy using a camera
    mounted on a hand held pole to satellite-based synthetic radar mapping
    of subcontinental scale hydrology of large rivers. In this overview
    each of the 12 articles is briefly summarized. Based on these works
    and other research, it is concluded that the time for more widespread
    application of river remote sensing techniques is now. To promote
    more widespread use of remote sensing techniques for river science
    and management, the following are advocated: (a) developing stand
    alone or plug-in software products that enable non-expert users to
    implement these new methods, (b) incorporating remote sensing of
    rivers training into classes, workshops, and on-line tutorials; and
    (c) promoting more intentional and formal collaboration among members
    of the river remote sensing community. Copyright (c) 2010 John Wiley
    & Sons, Ltd.
    BibTeX:
    @article{Marcus2010,
      author = {Marcus, WA and Fonstad, MA},
      title = {Remote sensing of rivers: the emergence of a subdiscipline in the river sciences},
      journal = {Earth Surface Processes and Landforms},
      year = {2010},
      volume = {35},
      number = {15},
      pages = {1867--1872}
    }
    					
    Power2010 Power, M.J.; Marlon, J.R.; Bartlein, P.J. & Harrison, S.P. Fire history and the Global Charcoal Database: A new tool for hypothesis testing and data exploration 2010 Palaeogeography Palaeoclimatology Palaeoecology
    Vol. 291 (1-2) , pp. 52-59  
    article
    Abstract: Version 1 of the Global Charcoal Database is now available for regional
    fire history reconstructions, data exploration, hypothesis testing,
    and evaluation of coupled climate-vegetation-fire model simulations.
    The charcoal database contains over 400 radiocarbon-dated records
    that document changes in charcoal abundance during the Late Quaternary.
    The aim of this public database is to stimulate cross-disciplinary
    research in fire sciences targeted at an increased understanding
    of the controls and impacts of natural and anthropogenic fire regimes
    on centennial-to-orbital timescales. We describe here the data standardization
    techniques for comparing multiple types of sedimentary charcoal records.
    Version 1 of the Global Charcoal Database has been used to characterize
    global and regional patterns in fire activity since the last glacial
    maximum. Recent studies using the charcoal database have explored
    the relation between climate and fire during periods of rapid climate
    change, including evidence of fire activity during the Younger Dryas
    Chronozone, and during the past two millennia. Published by Elsevier
    B.V.
    BibTeX:
    @article{Power2010,
      author = {Power, MJ and Marlon, JR and Bartlein, PJ and Harrison, SP},
      title = {Fire history and the Global Charcoal Database: A new tool for hypothesis testing and data exploration},
      journal = {Palaeogeography Palaeoclimatology Palaeoecology},
      year = {2010},
      volume = {291},
      number = {1-2},
      pages = {52--59}
    }
    					
    Shinker2010 Shinker, J.J. & Bartlein, P.J. Spatial variations of effective moisture in the western United States 2010 Geophysical Research Letters
    Vol. 37 , pp. -  
    article
    Abstract: Spatial patterns of actual evapotranspiration (AE), potential evapotranspiration
    (PE), and their ratio (AE/PE) in the western United States are examined
    to describe the annual cycle of moisture availability. Long-term
    (1971-2000) averages of observed temperature and precipitation, and
    sunshine data were used to calculate AE and PE. A cluster analysis
    identifies regions with similar annual cycles of AE/PE. We identify
    three different spatial scales of variability in AE/PE: (1) broadscale
    patterns reflect the trade-off between winter-dominated precipitation
    of the Pacific Northwest and summer-dominated precipitation east
    of the Rocky Mountains, and the south-to-north decrease in PE related
    to latitudinal variations in net radiation; (2) mesoscale patterns
    show the influence of regional-scale features (e. g., the North American
    Monsoon); and (3) local-scale patterns are related to topography.
    Understanding the scales of effective-moisture variations is valuable
    from the perspective of terrestrial ecosystems and water resources
    management in the mostly arid western United States. Citation: Shinker,
    J.J., and P.J. Bartlein (2010), Spatial variations of effective moisture
    in the western United States, Geophys. Res. Lett., 37, L02701, doi:10.1029/2009GL041387.
    BibTeX:
    @article{Shinker2010,
      author = {Shinker, JJ and Bartlein, PJ},
      title = {Spatial variations of effective moisture in the western United States},
      journal = {Geophysical Research Letters},
      year = {2010},
      volume = {37},
      pages = {--}
    }
    					
    Walsh2010 Walsh, M.K.; Pearl, C.A.; Whitlock, C.; Bartlein, P.J. & Worona, M.A. An 11 000-year-long record of fire and vegetation history at Beaver Lake, Oregon, central Willamette Valley 2010 Quaternary Science Reviews
    Vol. 29 (9-10) , pp. 1093-1106  
    article
    Abstract: High-resolution macroscopic charcoal and pollen analysis were used
    to reconstruct an 11 000-year-long record of fire and vegetation
    history from Beaver Lake, Oregon, the first complete Holocene paleoecological
    record from the floor of the Willamette Valley. In the early Holocene
    (ca 11 000-7500 calendar years before present [cal yr BP]), warmer,
    drier summers than at present led to the establishment of xeric woodland
    of Quercus, Corylus, and Pseudotsuga near the site. Disturbances
    (i.e., floods, fires) were common at this time and as a result Alnus
    rubra grew nearby. High fire frequency occurred in the early Holocene
    from ca 11 200-9300 cal yr BP. Riparian forest and wet prairie developed
    in the middle Holocene (ca 7500 cal yr BP), likely the result of
    a decrease in the frequency of flooding and a shift to effectively
    cooler, wetter conditions than before. The vegetation at Beaver Lake
    remained generally unchanged into the late Holocene (from 4000 cal
    yr BP to present), with the exception of land clearance associated
    with Euro-American settlement of the valley (ca 160 cal yr BP). Middle-to-late
    Holocene increases in fire frequency, coupled with abrupt shifts
    in fire-episode magnitude and charcoal composition, likely indicate
    the influence anthropogenic burning near the site. The paleoecological
    record from Beaver Lake, and in particular the general increase in
    fire frequency over the last 8500 years, differs significantly from
    other low-elevation sites in the Pacific Northwest, which suggests
    that local controls (e.g., shifts in vegetation structure, intensification
    of human land-use), rather than regional climatic controls, more
    strongly influenced its environmental history. (C) 2010 Elsevier
    Ltd. All rights reserved.
    BibTeX:
    @article{Walsh2010,
      author = {Walsh, MK and Pearl, CA and Whitlock, C and Bartlein, PJ and Worona, MA},
      title = {An 11 000-year-long record of fire and vegetation history at Beaver Lake, Oregon, central Willamette Valley},
      journal = {Quaternary Science Reviews},
      year = {2010},
      volume = {29},
      number = {9-10},
      pages = {1093--1106}
    }
    					
    Walsh2010a Walsh, M.K.; Whitlock, C. & Bartlein, P.J. 1200 years of fire and vegetation history in the Willamette Valley, Oregon and Washington, reconstructed using high-resolution macroscopic charcoal and pollen analysis 2010 Palaeogeography Palaeoclimatology Palaeoecology
    Vol. 297 (2) , pp. 273-289  
    article
    Abstract: High-resolution macroscopic charcoal and pollen analyses were used
    to reconstruct the fire and vegetation history of the Willamette
    Valley for the last 1200 years. Presented in this paper are three
    new paleoecological reconstructions from lake Oswego, Porter Lake,
    and Warner Lake, Oregon, and portions of previous reconstructions
    from Battle Ground lake, Washington, and Beaver Lake, Oregon. The
    reconstructions show that prior to Euro-American settlement vegetation
    and fire regimes were influenced by a combination of natural and
    anthropogenic factors. Battle Ground Lake shows a stronger influence
    from climate, while Lake Oswego, Beaver Lake, Porter Lake, and Warner
    Lake were more controlled by human activity. However, human-set fires
    were also modulated by regional climate variability during the Medieval
    Climate Anomaly and the Little Ice Age. Fire reconstructions from
    Battle Ground Lake, Lake Oswego, Beaver Lake, and Porter Lake imply
    that fires were infrequent in the Willamette Valley 200-300 years
    prior to Euro-American settlement. The decline of Native American
    populations due to introduced disease may have led to this reduction
    in fire activity. The prehistoric record from Warner Lake, however,
    indicates that fires in the foothills of the Cascade Range were more
    frequent than on the valley floor, at least until ca. AD 1800. The
    historic portions of the reconstructions indicate that Euro-American
    land clearance for agriculture and logging produced the most dramatic
    shifts in vegetation and fire regimes. All five records indicate
    that few fires in the Willamette Valley have occurred since ca. AD
    1930, and fires today are predominantly grass fires. (C) 2010 Elsevier
    B.V. All rights reserved.
    BibTeX:
    @article{Walsh2010a,
      author = {Walsh, MK and Whitlock, C and Bartlein, PJ},
      title = {1200 years of fire and vegetation history in the Willamette Valley, Oregon and Washington, reconstructed using high-resolution macroscopic charcoal and pollen analysis},
      journal = {Palaeogeography Palaeoclimatology Palaeoecology},
      year = {2010},
      volume = {297},
      number = {2},
      pages = {273--289}
    }
    					
    Blanton2009 Blanton, P. & Marcus, W.A. Railroads, roads and lateral disconnection in the river landscapes of the continental United States 2009 Geomorphology
    Vol. 112 (3-4) , pp. 212-227  
    article fluvial geomorphology
    Abstract: Railroads and roads are ubiquitous features in the river corridors
    of the United States. However, their impact on hydrologic, geomorphic,
    and ecological processes in fluvial and riparian landscapes has not
    been systematically explored at regional or continental extents.
    This study documents the geographic distribution of roads and railroads
    in the alluvial floodplains of the continental United States and
    the regional variability of their potential impacts on lateral connectivity
    and resultant channel and floodplain structure and function. We use
    national scale data sets and GIS analysis to derive data on stream-transportation
    network interactions in two broad categories: (1) crossing impacts,
    such as bridges and culverts, and (2) impacts where transportation
    infrastructure acts as a longitudinal dam along the stream channel,
    causing lateral floodplain disconnection. Potential stream crossing
    impacts are greatest in regions with long histories of road and railroad
    development and relatively low relief, such as the Mid-Atlantic,
    New England, and the Lower Mississippi and Ohio Valleys. Potential
    lateral disconnections are more prevalent in rugged regions such
    as the Western US. and Appalachians where transportation routes follow
    river corridors along valley bottoms. Based on these results, we
    develop a conceptual model that suggests that the area of lateral
    disconnection due to transportation infrastructure should be most
    extensive in mid-sized alluvial valleys in relatively rugged settings.
    The result of this disconnection is the disruption of the long-term,
    cut-and-fill alluviation and of the shorter-term flood and flow pulse
    processes that create and maintain ecosystem function in river landscapes.
    The tremendous extent of transportation infrastructure in alluvial
    valleys documented in this study suggests a revision to H.B.N. Hynes'
    statement that the valley rules the stream. Instead, it appears that
    in modem landscapes of the U.S. the valley rules the transportation
    network - and the transportation network rules the stream. (C) 2009
    Elsevier B.V. All fights reserved.
    BibTeX:
    @article{Blanton2009,
      author = {Blanton, P and Marcus, WA},
      title = {Railroads, roads and lateral disconnection in the river landscapes of the continental United States},
      journal = {Geomorphology},
      year = {2009},
      volume = {112},
      number = {3-4},
      pages = {212--227}
    }
    					
    Gavin2009 Gavin, D.G.; Hu, F.S.; Walker, I.R. & Westover, K. The northern inland temperate rainforest of British Columbia: old forests with a young history? 2009 Northwest Science
    Vol. 83 (1) , pp. 70-78  
    article
    Abstract: The inland temperate rainforest (ITR) in east-central British Columbia
    is marked by superlative examples of old-growth cedar-hemlock forest.
    How long has this old-growth forest structure been a major component
    of this landscape? What is the biological and conservation significance
    of the history of this forest type? Here we present paleoecological
    evidence from a study in the Robson Valley of the Upper Fraser River.
    Sediment cores from Gerry Lake and Redmountain Lake show that western
    hemlock and western redcedar increased in abundance only within the
    last 2000 years. Thus, the old-growth forests of the northern ITR
    may have been present for only a few generations of trees. It is
    even possible, based on our preliminary evidence, that the oldest
    western redcedar in these stands may be the first colonizing individuals
    at these sites. Further paleoecological studies, including a combination
    of stand-age structure and pollen analysis from small lakes and forest
    hollows, are needed in order to understand the historical significance
    of these stands. A recent establishment of the ITR has implications
    for understanding the assembly of the modern diverse biota of the
    region as well as how the biota will respond to future climate change.
    BibTeX:
    @article{Gavin2009,
      author = {Gavin, DG and Hu, FS and Walker, IR and Westover, K},
      title = {The northern inland temperate rainforest of British Columbia: old forests with a young history?},
      journal = {Northwest Science},
      year = {2009},
      volume = {83},
      number = {1},
      pages = {70--78}
    }
    					
    Gavin2009a Gavin, D.G. The coastal-disjunct mesic flora in the inland Pacific Northwest of USA and Canada: refugia, dispersal and disequilibrium 2009 Diversity and Distributions
    Vol. 15 (6) , pp. 972-982  
    article vegetation and climate
    Abstract: Aim Understanding the history of the mesic-adapted plant species of
    eastern British Columbia and northern Idaho, disjunct from their
    main coastal distribution, may suggest how biotas reorganize in the
    face of climate change and dispersal barriers. For different species,
    current evidence supports establishment of the disjunction via an
    inland glacial refugium, via recent dispersal from the coast, or
    via a combination of both. In this study, the modern distributions
    of the coastal-disjunct vascular plants are analysed with respect
    to modern climate to examine how refugia and/or dispersal limitation
    control regional patterns in species richness. Location North-west
    North America. Methods The distributions of nine tree and 58 understorey
    species with a coastal-disjunct pattern were compiled on a 50-km
    grid. The relationship between species richness and an estimate of
    available moisture was calculated separately for formerly glaciated
    and unglaciated portions of the coastal and inland regions. Growth
    habit and dispersal mode were assessed as possible explanatory variables
    for species distributions. Results Species richness shows a strong
    relationship to climate in coastal-unglaciated areas but no relationship
    to climate in inland-glaciated areas. In inland-glaciated areas,
    richness is c. 70% lower than that expected from climate. Species
    with animal-dispersed seeds occupy a larger portion of coastal and
    inland regions than species with less dispersal potential. Main conclusions
    Modern patterns of diversity are consistent with both refugia and
    dispersal processes in establishing the coastal-disjunct pattern.
    The inland glacial refugium is marked by locally high diversity and
    several co-distributed endemics. In the inland-glaciated area, dispersal
    limitation has constrained diversity despite the nearby refugia.
    Onset of mesic climate within only the last 3000 years and the low
    dispersal capacity of many species in the refugium may explain this
    pattern. This study suggests that vascular plant species will face
    significant challenges responding to climate change on fragmented
    landscapes.
    BibTeX:
    @article{Gavin2009a,
      author = {Gavin, DG},
      title = {The coastal-disjunct mesic flora in the inland Pacific Northwest of USA and Canada: refugia, dispersal and disequilibrium},
      journal = {Diversity and Distributions},
      year = {2009},
      volume = {15},
      number = {6},
      pages = {972--982}
    }
    					
    Lawler2009 Lawler, J.J.; Shafer, S.L.; White, D.; Kareiva, P.; Maurer, E.P.; Blaustein, A.R. & Bartlein, P.J. Projected climate-induced faunal change in the Western Hemisphere 2009 Ecology
    Vol. 90 (3) , pp. 588-597  
    article future climate and vegetation change
    Abstract: Climate change is predicted to be one of the greatest drivers of ecological
    change in the coming century. Increases in temperature over the last
    century have clearly been linked to shifts in species distributions.
    Given the magnitude of projected future climatic changes, we can
    expect even larger range shifts in the coming century. These changes
    will, in turn, alter ecological communities and the functioning of
    ecosystems. Despite the seriousness of predicted climate change,
    the uncertainty in climate-change projections makes it difficult
    for conservation managers and planners to proactively respond to
    climate stresses. To address one aspect of this uncertainty, we identified
    predictions of faunal change for which a high level of consensus
    was exhibited by different climate models. Specifically, we assessed
    the potential effects of 30 coupled atmosphere-ocean general circulation
    model (AOGCM) future-climate simulations on the geographic ranges
    of 2954 species of birds, mammals, and amphibians in the Western
    Hemisphere. Eighty percent of the climate projections based on a
    relatively low greenhouse-gas emissions scenario result in the local
    loss of at least 10% of the vertebrate fauna over much of North and
    South America. The largest changes in fauna are predicted for the
    tundra, Central America, and the Andes Mountains where, assuming
    no dispersal constraints, specific areas are likely to experience
    over 90% turnover, so that faunal distributions in the future will
    bear little resemblance to those of today.
    BibTeX:
    @article{Lawler2009,
      author = {Lawler, JJ and Shafer, SL and White, D and Kareiva, P and Maurer, EP and Blaustein, AR and Bartlein, PJ},
      title = {Projected climate-induced faunal change in the Western Hemisphere},
      journal = {Ecology},
      year = {2009},
      volume = {90},
      number = {3},
      pages = {588--597}
    }
    					
    Marlon2009 Marlon, J.R.; Bartlein, P.J.; Walsh, M.K.; Harrison, S.P.; Brown, K.J.; Edwards, M.E.; Higuera, P.E.; Power, M.J.; Anderson, R.S.; Briles, C.; Brunelle, A.; Carcaillet, C.; Daniels, M.; Hu, F.S.; Lavoie, M.; Long, C.; Minckley, T.; Richard, P.J.H.; Scott, A.C.; Shafer, D.S.; Tinner, W.; Umbanhowar, C.E. & Whitlock, C. Wildfire responses to abrupt climate change in North America 2009 Proceedings of the National Academy Of Sciences of the United States of the USA
    Vol. 106 (8) , pp. 2519-2524  
    article
    Abstract: It is widely accepted, based on data from the last few decades and
    on model simulations, that anthropogenic climate change will cause
    increased fire activity. However, less attention has been paid to
    the relationship between abrupt climate changes and heightened fire
    activity in the paleorecord. We use 35 charcoal and pollen records
    to assess how fire regimes in North America changed during the last
    glacial-interglacial transition ( 15 to 10 ka), a time of large and
    rapid climate changes. We also test the hypothesis that a comet impact
    initiated continental-scale wildfires at 12.9 ka; the data do not
    support this idea, nor are continent-wide fires indicated at any
    time during deglaciation. There are, however, clear links between
    large climate changes and fire activity. Biomass burning gradually
    increased from the glacial period to the beginning of the Younger
    Dryas. Although there are changes in biomass burning during the Younger
    Dryas, there is no systematic trend. There is a further increase
    in biomass burning after the Younger Dryas. Intervals of rapid climate
    change at 13.9, 13.2, and 11.7 ka are marked by large increases in
    fire activity. The timing of changes in fire is not coincident with
    changes in human population density or the timing of the extinction
    of the megafauna. Although these factors could have contributed to
    fire-regime changes at individual sites or at specific times, the
    charcoal data indicate an important role for climate, and particularly
    rapid climate change, in determining broad-scale levels of fire activity.
    BibTeX:
    @article{Marlon2009,
      author = {Marlon, JR and Bartlein, PJ and Walsh, MK and Harrison, SP and Brown, KJ and Edwards, ME and Higuera, PE and Power, MJ and Anderson, RS and Briles, C and Brunelle, A and Carcaillet, C and Daniels, M and Hu, FS and Lavoie, M and Long, C and Minckley, T and Richard, PJH and Scott, AC and Shafer, DS and Tinner, W and Umbanhowar, CE and Whitlock, C},
      title = {Wildfire responses to abrupt climate change in North America},
      journal = {Proceedings of the National Academy Of Sciences of the United States of the USA},
      year = {2009},
      volume = {106},
      number = {8},
      pages = {2519--2524}
    }
    					
    Shinker2009 Shinker, J.J. & Bartlein, P.J. Visualizing the Large-Scale Patterns of ENSO-Related Climate Anomalies in North America 2009 Earth Interactions
    Vol. 13 , pp. -  
    article
    Abstract: The variations of large-scale climatic controls and surface responses
    through the annual cycle during strong positive (El Nino) and negative
    (La Nina) phase ENSO events are analyzed to assess the within-year
    and among-year variations of climate anomalies. Data from the NCEP-NCAR
    reanalysis project are presented as small-multiple maps to illustrate
    the spatial and temporal variability in North American climate associated
    with extreme phases of ENSO. Temperature, mean sea level pressure,
    500-mb geopotential heights, and 850-mb specific humidity have composite-anomaly
    patterns that exhibit the greatest degree of spatial and temporal
    coherence. In general, the composite-anomaly patterns for El Nino
    and La Nina events are of opposite sign, with stronger, more spatially
    coherent anomalies occurring during El Nino events than during La
    Nina events. However, the strength and coherency of the precipitation
    anomaly patterns are reduced in the interior intermountain west during
    both positive and negative phase of ENSO. The variations in precipitation
    anomalies are compared to the 500-mb omega and 850-mb specific humidity
    composite-anomaly patterns, which provide information on the controls
    of precipitation by large-scale vertical motions and moisture availability
    thus providing information on the specific mechanisms associated
    with precipitation variability during ENSO events.
    BibTeX:
    @article{Shinker2009,
      author = {Shinker, JJ and Bartlein, PJ},
      title = {Visualizing the Large-Scale Patterns of ENSO-Related Climate Anomalies in North America},
      journal = {Earth Interactions},
      year = {2009},
      volume = {13},
      pages = {--}
    }
    					
    Steingisser2009 Steingisser, A. & Marcus, W.A. Human Impacts on geyser basins 2009 Yellowstone Science
    Vol. 17 , pp. 1-18  
    article
    BibTeX:
    @article{Steingisser2009,
      author = {Steingisser, A and Marcus, WA},
      title = {Human Impacts on geyser basins},
      journal = {Yellowstone Science},
      year = {2009},
      volume = {17},
      pages = {1-18}
    }
    					
    Tang2009 Tang, G.P.; Shafer, S.L.; Bartlein, P.J. & Holman, J.O. Effects of experimental protocol on global vegetation model accuracy: A comparison of simulated and observed vegetation patterns for Asia 2009 Ecological Modelling
    Vol. 220 (12) , pp. 1481-1491  
    article
    Abstract: Prognostic vegetation models have been widely used to study the interactions
    between environmental change and biological systems. This study examines
    the sensitivity of vegetation model simulations to: (i) the selection
    of input climatologies representing different time periods and their
    associated atmospheric CO2, concentrations, (ii) the choice of observed
    vegetation data for evaluating the model results, and (iii) the methods
    used to compare simulated and observed vegetation. We use vegetation
    simulated for Asia by the equilibrium vegetation model BIOME4 as
    a typical example of vegetation model output. BIOME4 was run using
    19 different climatologies and their associated atmospheric CO2 concentrations.
    The Kappa statistic, Fuzzy Kappa statistic and a newly developed
    map-comparison method, the Nomad index, were used to quantify the
    agreement between the biomes simulated under each scenario and the
    observed vegetation from three different global land- and tree-cover
    data sets: the global Potential Natural Vegetation data set (PNV),
    the Global Land Cover Characteristics data set (GLCC), and the Global
    Land Cover Facility data set (GLCF). The results indicate that the
    30-year mean climatology (and its associated atmospheric CO2 concentration)
    for the time period immediately preceding the collection date of
    the observed vegetation data produce the most accurate vegetation
    simulations when compared with all three observed vegetation data
    sets. The study also indicates that the BIOME4-simulated vegetation
    for Asia more closely matches the PNV data than the other two observed
    vegetation data sets. Given the same observed data, the accuracy
    assessments of the BIOME4 simulations made using the Kappa, Fuzzy
    Kappa and Nomad index map-comparison methods agree well when the
    compared vegetation types consist of a large number of spatially
    continuous grid cells. The results of this analysis can assist model
    users in designing experimental protocols for simulating vegetation.
    (C) 2009 Elsevier B.V. All rights reserved.
    BibTeX:
    @article{Tang2009,
      author = {Tang, GP and Shafer, SL and Bartlein, PJ and Holman, JO},
      title = {Effects of experimental protocol on global vegetation model accuracy: A comparison of simulated and observed vegetation patterns for Asia},
      journal = {Ecological Modelling},
      year = {2009},
      volume = {220},
      number = {12},
      pages = {1481--1491}
    }
    					
    Williams2009 Williams, J.W.; Shuman, B. & Bartlein, P.J. Rapid responses of the prairie-forest ecotone to early Holocene aridity in mid-continental North America 2009 Global and Planetary Change
    Vol. 66 (3-4) , pp. 195-207  
    article paleoecology and paleoclimatology
    Abstract: The prairie-forest transition in midcontinental North America is a
    major physiognomic boundary, and its shifts during the Holocene are
    a classic example of climate-driven ecotonal dynamics. Recent work
    suggests asymmetrical Holocene behavior, with a relatively rapid
    early Holocene deforestation and more gradual reforestation later
    in the Holocene. This paper presents a new synthesis of the Holocene
    history of the Great Plains prairie-forest ecotone in the north-central
    US and central Canada that updates prior mapping efforts and systematically
    assesses rates of change. Changes in percent woody cover (%WC) are
    inferred from fossil pollen records, using the modern analog technique
    and surface-sediment pollen samples cross-referenced against remotely
    sensed observations. For contemporary pollen samples from the Great
    Plains, %WC linearly correlates to percent arboreal pollen (%AP),
    but regression parameters vary interregionally. At present, %AP is
    consistently higher than %WC, because of high background levels of
    arboreal pollen. Holocene maps of the eastern prairie-forest ecotone
    agree with prior maps, showing a rapid decrease in %WC and eastward
    prairie advance between 10,000 and 8000 ka (1 ka = 1000 calibrated
    years before present), a maximum eastward position of the ecotone
    from 7 to 6 ka, and increased %WC and westward prairie retreat after
    6 ka. Ecotone position is ambiguous in Iowa and southeastern Minnesota,
    due to a scarcity of modern analogs for early-Holocene samples with
    high Minus abundances and for samples from alluvial sediments. The
    northern prairie-forest ecotone was positioned in central Saskatchewan
    between 12 and 10 ka, stabilized from 10 to 6 ka despite decreases
    in %WC at some sites, then moved south after 6 ka. In both east and
    north. ecotonal movements are consistent with a dry early Holocene
    and increasing moisture availability after 6 ka. Sites near the ecotone
    consistently show an asymmetric pattern of abrupt early Holocene
    deforestation (<300 years) and gradual reforestation after 6 ka.
    Early Holocene decreases in %WC are faster than the corresponding
    drops in %AP, because the analog-based %WC reconstructions correct
    for the high background levels of arboreal pollen types that blur
    temporal variations in %AP. For example, at Elk Like. the %AP decline
    lasts 1000 years, whereas the %WC decline occurs between adjacent
    pollen samples, approximately 300 years apart. Thus, early Holocene
    deforestation may have been even more abrupt than previously recognized.
    Rapid deforestation likely was promoted both by rapid climate changes
    around 8.2 ka and positive fire-vegetation feedbacks. Non-linear
    vegetational responses to hydrological variability are consistent
    with 1) other paleorecords showing rapid die-offs of some eastern
    tree species in response to aridity and 2) observations of threshold-type
    ecological responses to recent climate events. The 21st-century trajectory
    for the Great Plains prairie-forest ecotone is uncertain, because
    climate models differ over the direction of regional precipitation
    trends. but future drying would be more likely to trigger threshold-type
    shifts in ecotone position. (c) 2008 Elsevier B.V. All rights reserved.
    BibTeX:
    @article{Williams2009,
      author = {Williams, JW and Shuman, B and Bartlein, PJ},
      title = {Rapid responses of the prairie-forest ecotone to early Holocene aridity in mid-continental North America},
      journal = {Global and Planetary Change},
      year = {2009},
      volume = {66},
      number = {3-4},
      pages = {195--207}
    }
    					
    Bartlein2008 Bartlein, P.J.; Hostetler, S.W.; Shafer, S.L.; Holman, J.O. & Solomon, A.M. Temporal and spatial structure in a daily wildfire-start data set from the western United States (1986-96) 2008 International Journal of Wildland Fire
    Vol. 17 (1) , pp. 8-17  
    article
    Abstract: The temporal and spatial structure of 332 404 daily fire-start records
    from the western United States for the period 1986 through 1996 is
    illustrated using several complimentary visualisation techniques.
    We supplement maps and time series plots with Hovmoller diagrams
    that reduce the spatial dimensionality of the daily data in order
    to reveal the underlying space-time structure. The mapped distributions
    of all lightning- and human-started fires during the 11-year interval
    show similar first-order patterns that reflect the broad-scale distribution
    of vegetation across the West and the annual cycle of climate. Lightning-started
    fires are concentrated in the summer half-year and occur in widespread
    outbreaks that last a few days and reflect coherent weather-related
    controls. In contrast, fires started by humans occur throughout the
    year and tend to be concentrated in regions surrounding large-population
    centres or intensive-agricultural areas. Although the primary controls
    of human-started fires are their location relative to burnable fuel
    and the level of human activity, spatially coherent, weather-related
    variations in their incidence can also be noted.
    BibTeX:
    @article{Bartlein2008,
      author = {Bartlein, PJ and Hostetler, SW and Shafer, SL and Holman, JO and Solomon, AM},
      title = {Temporal and spatial structure in a daily wildfire-start data set from the western United States (1986-96)},
      journal = {International Journal of Wildland Fire},
      year = {2008},
      volume = {17},
      number = {1},
      pages = {8--17}
    }
    					
    Beckage2008 Beckage, B.; Osborne, B.; Gavin, D.G.; Pucko, C.; Siccama, T. & Perkins, T. A rapid upward shift of a forest ecotone during 40 years of warming in the Green Mountains of Vermont 2008 Proceedings of the National Academy of Sciences of the USA
    Vol. 105 (11) , pp. 4197-4202  
    article
    Abstract: Detecting latitudinal range shifts of forest trees in response to
    recent climate change is difficult because of slow demographic rates
    and limited dispersal but may be facilitated by spatially compressed
    climatic zones along elevation gradients in montane environments.
    We resurveyed forest plots established in 1964 along elevation transects
    in the Green Mountains (Vermont) to examine whether a shift had occurred
    in the location of the northern hardwood-boreal forest ecotone (NBE)
    from 1964 to 2004. We found a 19% increase in dominance of northern
    hard-woods from 70% in 1964 to 89% in 2004 in the lower half of the
    NBE. This shift was driven by a decrease (up to 76%) in boreal and
    increase (up to 16%) in northern hardwood basal area within the lower
    portions of the ecotone. We used aerial photographs and satellite
    imagery to estimate a 91- to 119-m upslope shift in the upper limits
    of the NBE from 1962 to 2005. The upward shift is consistent with
    regional climatic change during the same period; interpolating climate
    data to the NBE showed a 1.1 degrees C increase in annual temperature,
    which would predict a 208-m upslope movement of the ecotone, along
    with a 34% increase in precipitation. The rapid upward movement of
    the NBE indicates. little inertia to climatically induced range shifts
    in montane forests; the upslope shift may have been accelerated by
    high turnover in canopy trees that provided opportunities for ingrowth
    of lower elevation species. Our results indicate that high-elevation
    forests may be jeopardized by climate change sooner than anticipated.
    BibTeX:
    @article{Beckage2008,
      author = {Beckage, B and Osborne, B and Gavin, DG and Pucko, C and Siccama, T and Perkins, T},
      title = {A rapid upward shift of a forest ecotone during 40 years of warming in the Green Mountains of Vermont},
      journal = {Proceedings of the National Academy of Sciences of the USA},
      year = {2008},
      volume = {105},
      number = {11},
      pages = {4197--4202}
    }
    					
    Briles2008 Briles, C.E.; Whitlock, C.; Bartlein, P.J. & Higuera, P. Regional and local controls on postglacial vegetation and fire in the Siskiyou Mountains, northern California, USA 2008 Palaeogeography Palaeoclimatology Palaeoecology
    Vol. 265 (1-2) , pp. 159-169  
    article fire: modern and paleo
    Abstract: The Siskiyou Mountains of northwestern California and southwestern
    Oregon are a floristic hotspot, and the high diversity of conifers
    there likely results from a combination of geological, ecological,
    climatological and historical factors. To evaluate how past climate
    variability has influenced the composition, structure and fire regime
    of the Siskiyou forests, pollen, charcoal, and lithological evidence
    was examined from two lakes along a moisture gradient to reconstruct
    the vegetation, fire and climate history. The late-glacial/Early
    Holocene transition period, subalpine parkland was replaced by a
    closed forest of Pinus, Cupressaceae, Abies and Pseudotsuga and more
    frequent fires a 1000 years earlier at the wetter site, and it is
    likely that reduced Pacific Ocean upwelling created warmer drier
    conditions at the coast. In the Early Holocene, Pinus, Cupressaceae
    were less abundant and fire less frequent at the coastal site during
    a period of increased coastal upwelling and fog production. In the
    Late Holocene, Abies, Pseudotsuga, Pinus, and Quercus vaccinifolia
    increased in the forest at both sites suggesting a widespread response
    to cooling. Fewer fires at the wetter site may account for the abundance
    of Picea breweriana within the last 1000 years. The comparison of
    the two records implies that large-scale controls in climate during
    the last 14,000 cal yr BP have resulted in major changes in vegetation
    and fire regime. Asynchrony in the ecosystem response of wetter and
    drier sites arises from small-scale spatial variations in effective
    moisture and temperature resulting from topographically-influenced
    microclimates and coastal-to-inland climate gradients. (C) 2008 Elsevier
    B.V. All rights reserved.
    BibTeX:
    @article{Briles2008,
      author = {Briles, CE and Whitlock, C and Bartlein, PJ and Higuera, P},
      title = {Regional and local controls on postglacial vegetation and fire in the Siskiyou Mountains, northern California, USA},
      journal = {Palaeogeography Palaeoclimatology Palaeoecology},
      year = {2008},
      volume = {265},
      number = {1-2},
      pages = {159--169}
    }
    					
    Chase2008 Chase, M.; Bleskie, C.; Walker, I.R.; Gavin, D.G. & Hu, F.S. Midge-inferred Holocene summer temperatures in Southeastern British Columbia, Canada 2008 Palaeogeography Palaeoclimatology Palaeoecology
    Vol. 257 (1-2) , pp. 244-259  
    article
    Abstract: Using fossil midge stratigraphies, we inferred Holocene summer temperatures
    at three subalpine lakes in eastern British Columbia. The late-glacial
    sediment indicated cool conditions, with an abundance of Microspectra
    atrofasciata/radialis type fossils at Thunder Lake and Redmountain
    Lake, and Sergentia at Windy Lake. Sergentia and Tanytarsus lugens/Corynocera
    oliveri type were dominant in the early Holocene, together with Chironomus
    at Redmountain Lake. At Thunder and Windy lakes, the early Holocene
    was dominated by warm-adapted taxa such as Microtendipes. Quantitative
    midge-temperature inference models reconstruct a 4 to 8 degrees C
    rise in mean July air temperature for Windy and Thunder lakes at
    the Pleistocene/Holocene transition. Early-Holocene temperatures
    averaged 3 to 4 degrees C warmer than those extant today. In contrast,
    no long-term temperature trend was evident at Redmountain Lake. This
    site may not reflect actual trends in air temperature due to runoff
    from a persistent snow pack in the watershed. Comparison of midge
    and pollen data suggests an inverse relationship between summer temperature
    and precipitation through the middle to late Holocene. (C) 2007 Elsevier
    B.V. All rights reserved.
    BibTeX:
    @article{Chase2008,
      author = {Chase, M and Bleskie, C and Walker, IR and Gavin, DG and Hu, FS},
      title = {Midge-inferred Holocene summer temperatures in Southeastern British Columbia, Canada},
      journal = {Palaeogeography Palaeoclimatology Palaeoecology},
      year = {2008},
      volume = {257},
      number = {1-2},
      pages = {244--259}
    }
    					
    Gavin2008 Gavin, D.G.; Beckage, B. & Osborne, B. Forest dynamics and the growth decline of red spruce and sugar maple on Bolton Mountain, Vermont: a comparison of modeling methods 2008 Canadian Journal of Forest Research
    Vol. 38 (10) , pp. 2635-2649  
    article
    Abstract: Montane forests in the northeastern United States have experienced
    symptoms of declining vigor, such as branch dieback and increased
    mortality, over the last half-century. These declines have been attributed
    to the cumulative impacts of acid deposition, but reconstructing
    these declines from tree-ring records has proved difficult because
    of confounding factors that affect low-frequency growth patterns,
    including climate and natural growth trajectories following disturbance.
    We obtained tree-ring records of red spruce (Picea rubens Sarg.)
    and sugar maple (Acer saccharum L.) from three elevations on Bolton
    Mountain, Vermont, and applied traditional dendroclimatological analyses
    that revealed a profound declining growth-climate correlation since
    ca. 1970 for sugar maple but much less so for red spruce. We then
    applied a new multifaceted statistical approach that conservatively
    detrends tree-ring records by minimizing the influences of tree size,
    age, and canopy disturbances on radial growth. In contrast with the
    traditional analysis, this approach yielded chronologies that were
    consistently correlated with climate but with important exceptions.
    Low-elevation sugar maple suffered distinct episodes of slow growth,
    likely because of insect defoliators, and also a progressive decline
    since ca. 1988. Red spruce experienced subdecadal episodes of decline
    that may be related to freeze-thaw events known to injure foliage
    but showed no evidence of a progressive decline. This analysis was
    supported by a forest plot resurvey that indicated major declines
    in these species.
    BibTeX:
    @article{Gavin2008,
      author = {Gavin, DG and Beckage, B and Osborne, B},
      title = {Forest dynamics and the growth decline of red spruce and sugar maple on Bolton Mountain, Vermont: a comparison of modeling methods},
      journal = {Canadian Journal of Forest Research},
      year = {2008},
      volume = {38},
      number = {10},
      pages = {2635--2649}
    }
    					
    Marcus2008 Marcus, W.A. & Fonstad, M.A. Optical remote mapping of rivers at sub-meter resolutions and watershed extents 2008 Earth Surface Processes and Landforms
    Vol. 33 (1) , pp. 4-24  
    article
    Abstract: At watershed extents, our understanding of river form, process and
    function is largely based on locally intensive mapping of river reaches,
    or on spatially extensive but low density data scattered throughout
    a watershed (e.g. cross sections). The net effect has been to characterize
    streams as discontinuous systems. Recent advances in optical remote
    sensing of rivers indicate that it should now be possible to generate
    accurate and continuous maps of in-stream habitats, depths, algae,
    wood, stream power and other features at sub-meter resolutions across
    entire watersheds so long as the water is clear and the aerial view
    is unobstructed. Such maps would transform river science and management
    by providing improved data, better models and explanation, and enhanced
    applications. Obstacles to achieving this vision include variations
    in optics associated with shadows, water clarity, variable substrates
    and target-sun angle geometry. Logistical obstacles are primarily
    due to the reliance of existing ground validation procedures on time-of-flight
    field measurements, which are impossible to accomplish at watershed
    extents, particularly in large and difficult to access river basins.
    Philosophical issues must also be addressed that relate to the expectations
    around accuracy assessment, the need for and utility of physically
    based models to evaluate remote sensing results and the ethics of
    revealing information about river resources at fine spatial resolutions.
    Despite these obstacles and issues, catchment extent remote river
    mapping is now feasible, as is demonstrated by a proof-of-concept
    example for the Nueces River, Texas, and examples of how different
    image types (radar, lidar, thermal) could be merged with optical
    imagery. The greatest obstacle to development and implementation
    of more remote sensing, catchment scale 'river observatories' is
    the absence of broadly based funding initiatives to support collaborative
    research by multiple investigators in different river settings. Copyright
    (c) 2007 John Wiley & Sons, Ltd.
    BibTeX:
    @article{Marcus2008,
      author = {Marcus, WA and Fonstad, MA},
      title = {Optical remote mapping of rivers at sub-meter resolutions and watershed extents},
      journal = {Earth Surface Processes and Landforms},
      year = {2008},
      volume = {33},
      number = {1},
      pages = {4--24}
    }
    					
    Marlon2008 Marlon, J.R.; Bartlein, P.J.; Carcaillet, C.; Gavin, D.G.; Harrison, S.P.; Higuera, P.E.; Joos, F.; Power, M.J. & Prentice, I.C. Climate and human influences on global biomass burning over the past two millennia 2008 Nature Geoscience
    Vol. 1 (10) , pp. 697-702  
    article
    Abstract: Large, well-documented wildfires have recently generated worldwide
    attention, and raised concerns about the impacts of humans and climate
    change on wildfire regimes. However, comparatively little is known
    about the patterns and driving forces of global fire activity before
    the twentieth century. Here we compile sedimentary charcoal records
    spanning six continents to document trends in both natural and anthropogenic
    biomass burning for the past two millennia. We find that global biomass
    burning declined from AD 1 to similar to 1750, before rising sharply
    between 1750 and 1870. Global burning then declined abruptly after
    1870. The early decline in biomass burning occurred in concert with
    a global cooling trend and despite a rise in the human population.
    We suggest the subsequent rise was linked to increasing human influences,
    such as population growth and land-use changes. Our compilation suggests
    that the final decline occurred despite increasing air temperatures
    and population. We attribute this reduction in the amount of biomass
    burned over the past 150 years to the global expansion of intensive
    grazing, agriculture and fire management.
    BibTeX:
    @article{Marlon2008,
      author = {Marlon, JR and Bartlein, PJ and Carcaillet, C and Gavin, DG and Harrison, SP and Higuera, PE and Joos, F and Power, MJ and Prentice, IC},
      title = {Climate and human influences on global biomass burning over the past two millennia},
      journal = {Nature Geoscience},
      year = {2008},
      volume = {1},
      number = {10},
      pages = {697--702}
    }
    					
    Minckley2008 Minckley, T.A.; Bartlein, P.J.; Whitlock, C.; Shuman, B.N.; Williams, J.W. & Davis, O.K. Associations among modern pollen, vegetation, and climate in western North America 2008 Quaternary Science Reviews
    Vol. 27 (21-22) , pp. 1962-1991  
    article
    Abstract: A compilation of 1884 modern pollen surface samples was analyzed to
    explore the relationships between spatial distributions of pollen
    percentage data vs. climate and vegetation in western North America.
    Modern pollen spectra capture many of the unique traits of regional
    vegetation patterns and reflect regional patterns of climate diversity.
    Large-scale vegetation differences were identifiable by their pollen
    signatures. At the coarsest scale, forested regions were dominated
    by arboreal pollen and Pinus pollen abundances were typically >30%.
    In contrast, non-forested regions were dominated by shrub and herbaceous
    pollen types with Pinus percentages typically <30%. At finer scales,
    indicator taxa were useful for identifying vegetation types. For
    example, Picea was a good first-order indicator of boreal spruce
    forest vegetation with relatively high median percentages (22%),
    whereas Quercus was a good first-order indicator of desert vegetation
    with low median percentages (1%). Pollen abundance also provided
    climatic information. High Betula percentages occurred over a relatively
    narrow climatic range corresponding with their high latitudinal distribution,
    high Artemisia percentages were registered in winter-cold and dry
    climates of the interior basins. Arboreal pollen types were abundant
    in cool and wet climates, while non-arboreal pollen types dominate
    in climates that are warm and dry. Using pollen assemblages to predict
    local climate conditions shows that climate conditions are well predicted
    given knowledge of pollen spectra and climate conditions of the nearest
    analogues. Low accuracy was evident with pollen-based climate predictions
    in desert regions and temperate rainforests because of either poor
    sample density (in the case of the former) or extremes in temperature
    and/or precipitation (in the case of both). In other regions, vegetation
    and climate space were accurately predicted even when proximal samples,
    within 100 km, are excluded as the possible analogues. These results
    show that, within the vegetation and climate space of this region,
    the modern-analogue technique is useful for quantifying broad-scale
    vegetation and climate changes. (C) 2008 Elsevier Ltd. All rights
    reserved.
    BibTeX:
    @article{Minckley2008,
      author = {Minckley, TA and Bartlein, PJ and Whitlock, C and Shuman, BN and Williams, JW and Davis, OK},
      title = {Associations among modern pollen, vegetation, and climate in western North America},
      journal = {Quaternary Science Reviews},
      year = {2008},
      volume = {27},
      number = {21-22},
      pages = {1962--1991}
    }
    					
    Power2008 Power, M.J.; Marlon, J.; Ortiz, N.; Bartlein, P.J.; Harrison, S.P.; Mayle, F.E.; Ballouche, A.; Bradshaw, R.H.W.; Carcaillet, C.; Cordova, C.; Mooney, S.; Moreno, P.I.; Prentice, I.C.; Thonicke, K.; Tinner, W.; Whitlock, C.; Zhang, Y.; Zhao, Y.; Ali, A.A.; Anderson, R.S.; Beer, R.; Behling, H.; Briles, C.; Brown, K.J.; Brunelle, A.; Bush, M.; Camill, P.; Chu, G.Q.; Clark, J.; Colombaroli, D.; Connor, S.; Daniau, A.L.; Daniels, M.; Dodson, J.; Doughty, E.; Edwards, M.E.; Finsinger, W.; Foster, D.; Frechette, J.; Gaillard, M.J.; Gavin, D.G.; Gobet, E.; Haberle, S.; Hallett, D.J.; Higuera, P.; Hope, G.; Horn, S.; Inoue, J.; Kaltenrieder, P.; Kennedy, L.; Kong, Z.C.; Larsen, C.; Long, C.J.; Lynch, J.; Lynch, E.A.; McGlone, M.; Meeks, S.; Mensing, S.; Meyer, G.; Minckley, T.; Mohr, J.; Nelson, D.M.; New, J.; Newnham, R.; Noti, R.; Oswald, W.; Pierce, J.; Richard, P.J.H.; Rowe, C.; Goni, M.F.S.; Shuman, B.N.; Takahara, H.; Toney, J.; Turney, C.; Urrego-Sanchez, D.H.; Umbanhowar, C.; Vandergoes, M.; Vanniere, B.; Vescovi, E.; Walsh, M.; Wang, X.; Williams, N.; Wilmshurst, J. & Zhang, J.H. Changes in fire regimes since the Last Glacial Maximum: an assessment based on a global synthesis and analysis of charcoal data 2008 Climate Dynamics
    Vol. 30 (7-8) , pp. 887-907  
    article
    Abstract: Fire activity has varied globally and continuously since the last
    glacial maximum (LGM) in response to long-term changes in global
    climate and shorter-term regional changes in climate, vegetation,
    and human land use. We have synthesized sedimentary charcoal records
    of biomass burning since the LGM and present global maps showing
    changes in fire activity for time slices during the past 21,000 years
    (as differences in charcoal accumulation values compared to pre-industrial).
    There is strong broad-scale coherence in fire activity after the
    LGM, but spatial heterogeneity in the signals increases thereafter.
    In North America, Europe and southern South America, charcoal records
    indicate less-than-present fire activity during the deglacial period,
    from 21,000 to similar to 11,000 cal yr BP. In contrast, the tropical
    latitudes of South America and Africa show greater-than-present fire
    activity from similar to 19,000 to similar to 17,000 cal yr BP and
    most sites from Indochina and Australia show greater-than-present
    fire activity from 16,000 to similar to 13,000 cal yr BP. Many sites
    indicate greater-than-present or near-present activity during the
    Holocene with the exception of eastern North America and eastern
    Asia from 8,000 to similar to 3,000 cal yr BP, Indonesia and Australia
    from 11,000 to 4,000 cal yr BP, and southern South America from 6,000
    to 3,000 cal yr BP where fire activity was less than present. Regional
    coherence in the patterns of change in fire activity was evident
    throughout the post-glacial period. These complex patterns can largely
    be explained in terms of large-scale climate controls modulated by
    local changes in vegetation and fuel load.
    BibTeX:
    @article{Power2008,
      author = {Power, MJ and Marlon, J and Ortiz, N and Bartlein, PJ and Harrison, SP and Mayle, FE and Ballouche, A and Bradshaw, RHW and Carcaillet, C and Cordova, C and Mooney, S and Moreno, PI and Prentice, IC and Thonicke, K and Tinner, W and Whitlock, C and Zhang, Y and Zhao, Y and Ali, AA and Anderson, RS and Beer, R and Behling, H and Briles, C and Brown, KJ and Brunelle, A and Bush, M and Camill, P and Chu, GQ and Clark, J and Colombaroli, D and Connor, S and Daniau, AL and Daniels, M and Dodson, J and Doughty, E and Edwards, ME and Finsinger, W and Foster, D and Frechette, J and Gaillard, MJ and Gavin, DG and Gobet, E and Haberle, S and Hallett, DJ and Higuera, P and Hope, G and Horn, S and Inoue, J and Kaltenrieder, P and Kennedy, L and Kong, ZC and Larsen, C and Long, CJ and Lynch, J and Lynch, EA and McGlone, M and Meeks, S and Mensing, S and Meyer, G and Minckley, T and Mohr, J and Nelson, DM and New, J and Newnham, R and Noti, R and Oswald, W and Pierce, J and Richard, PJH and Rowe, C and Goni, MFS and Shuman, BN and Takahara, H and Toney, J and Turney, C and Urrego-Sanchez, DH and Umbanhowar, C and Vandergoes, M and Vanniere, B and Vescovi, E and Walsh, M and Wang, X and Williams, N and Wilmshurst, J and Zhang, JH},
      title = {Changes in fire regimes since the Last Glacial Maximum: an assessment based on a global synthesis and analysis of charcoal data},
      journal = {Climate Dynamics},
      year = {2008},
      volume = {30},
      number = {7-8},
      pages = {887--907}
    }
    					
    Tang2008 Tang, G.P. & Bartlein, P.J. Simulating the climatic effects on vegetation: approaches, issues and challenges 2008 Progress in Physical Geography
    Vol. 32 (5) , pp. 543-556  
    article
    Abstract: Vegetation modelling has been viewed as a major approach for examining
    the dynamics of vegetation under climatic change. However, the characterization
    of uncertainty of model results is still a key Issue. In order to
    improve future model-based research, it is important to synthesize
    the current approaches and the issues that arise in vegetation modelling
    and to propose potential strategies for improving model-based research.
    This study first reviews the progress of vegetation models from static-equilibrium
    to transient-dynamic and to current coupled multi-objective vegetation
    models. Then, the four main sources leading to the uncertainty of
    model results are described, including (1) factors related to vegetation
    models (their structure, assumption and parameterization), (2) the
    data used to run a model, (3) the approaches used to validate model
    results, and (4) the spatiotemporal scaling issues involved in vegetation
    modelling. Finally, four strategies are proposed for improving future
    model-based research. These include improvements in the model structure
    and parameterization, enhancement of the quality of analytical data,
    improvement of the analytical approaches, and continued development
    of coupled dynamic vegetation models. Using a literature synthesis,
    this study provides researchers with a general guidance on applying
    vegetation models for simulating the effects of climatic variations
    on terrestrial vegetation.
    BibTeX:
    @article{Tang2008,
      author = {Tang, GP and Bartlein, PJ},
      title = {Simulating the climatic effects on vegetation: approaches, issues and challenges},
      journal = {Progress in Physical Geography},
      year = {2008},
      volume = {32},
      number = {5},
      pages = {543--556}
    }
    					
    Thompson2008 Thompson, R.S.; Anderson, K.H. & Bartlein, P.J. Quantitative estimation of bioclimatic parameters from presence/absence vegetation data in North America by the modern analog technique 2008 Quaternary Science Reviews
    Vol. 27 (11-12) , pp. 1234-1254  
    article modern climate analogues
    Abstract: The method of modern analogs is widely used to obtain estimates of
    past climatic conditions from paleobiological assemblages, and despite
    its frequent use, this method involved so-far untested assumptions.
    We applied four analog approaches to a continental-scale set of bioclimatic
    and plant-distribution presence/absence data for North America to
    assess how well this method works under near-optimal modern conditions.
    For each point on the grid, we calculated the similarity between
    its vegetation assemblage and those of all other points on the grid
    (excluding nearby points). The climate of the points with the most
    similar vegetation was used to estimate the climate at the target
    grid point. Estimates based the use of the Jaccard similarity coefficient
    had smaller errors than those based on the use of a new similarity
    coefficient, although the latter may be more robust because it does
    not assume that the "fossil" assemblage is complete. The results
    of these analyses indicate that presence/absence vegetation assemblages
    provide a valid basis for estimating bioclimates on the continental
    scale. However, the accuracy of the estimates is strongly tied to
    the number of species in the target assemblage, and the analog method
    is necessarily constrained to produce estimates that fall within
    the range of observed values. We applied the four modern analog approaches
    and the mutual overlap (or "mutual climatic range") method to estimate
    bioclimatic conditions represented by the plant macrofossil assemblage
    from a packrat midden of Last Glacial Maximum age from southern Nevada.
    In general, the estimation approaches produced similar results in
    regard to moisture conditions, but there was a greater range of estimates
    for growing-degree days. Despite its limitations, the modern analog
    technique can provide paleoclimatic reconstructions that serve as
    the starting point to the interpretation of past climatic conditions.
    Published by Elsevier Ltd.
    BibTeX:
    @article{Thompson2008,
      author = {Thompson, RS and Anderson, KH and Bartlein, PJ},
      title = {Quantitative estimation of bioclimatic parameters from presence/absence vegetation data in North America by the modern analog technique},
      journal = {Quaternary Science Reviews},
      year = {2008},
      volume = {27},
      number = {11-12},
      pages = {1234--1254}
    }
    					
    Walsh2008 Walsh, M.K.; Whitlock, C. & Bartlein, P.J. A 14,300-year-long record of fire-vegetation-climate linkages at Battle Ground Lake, southwestern Washington 2008 Quaternary Research
    Vol. 70 (2) , pp. 251-264  
    article
    Abstract: High-resolution macroscopic charcoal analysis was used to reconstruct
    a 14,300-year-long Fire history record from the lower Columbia River
    Valley in southwestern Washington, which was compared to a previous
    vegetation reconstruction for the site. In the late-glacial period
    (ca. 14,300-13,100 cal yr BP), Pinus/Picea-dominated parkland supported
    little to no fire activity. From the late-glacial to the early Holocene
    (ca. 13,100-10,800 cal yr BP), Pseudotsuga/Abies-dominated forest
    featured more frequent fire episodes that burned mostly woody vegetation.
    In the early to middle Holocene (ca. 10,800-5200 cal yr BP), Quercus-dominated
    savanna was associated with frequent fire episodes of low-to-moderate
    severity, with art increased herbaceous (i.e., grass) charcoal content.
    From the middle to late Holocene (ca. 5200 cal yr BP to present),
    forest dominated by Pseudotsuga, Thuja-type, and Tsuga heterophylla
    supported less frequent, but mostly large or high-severity fire episodes.
    Fire episodes were least frequent, but were largest or most severe,
    after ca. 2500 cal yr BP. The fire history at Battle Ground Lake
    was apparently driven by climate, directly through the length and
    severity of the fire season, and indirectly through climate-driven
    vegetation shifts, which affected available fuel biomass. (C) 2008
    University of Washington. All rights reserved.
    BibTeX:
    @article{Walsh2008,
      author = {Walsh, MK and Whitlock, C and Bartlein, PJ},
      title = {A 14,300-year-long record of fire-vegetation-climate linkages at Battle Ground Lake, southwestern Washington},
      journal = {Quaternary Research},
      year = {2008},
      volume = {70},
      number = {2},
      pages = {251--264}
    }
    					
    Whitlock2008 Whitlock, C.; Marlon, J.; Briles, C.; Brunelle, A.; Long, C. & Bartlein, P. Long-term relations among fire, fuel, and climate in the north-western US based on lake-sediment studies 2008 International Journal of Wildland Fire
    Vol. 17 (1) , pp. 72-83  
    article
    Abstract: Pollen and high-resolution charcoal records from the north-western
    USA provide an opportunity to examine the linkages among fire, climate,
    and fuels on multiple temporal and spatial scales. The data suggest
    that general charcoal levels were low in the late-glacial period
    and increased steadily through the last 11 000 years with increasing
    fuel biomass. At local scales, fire occurrence is governed by the
    interaction of site controls, including vegetation, local climate
    and fire weather, and topography. At subregional scales, patterns
    in the long term fire-episode frequency data are apparent: The Coast
    Range had relatively few fires in the Holocene, whereas the Klamath-Siskiyou
    region experienced frequent fire episodes. Fire regimes in the northern
    Rocky Mountains have been strongly governed by millennial- and centennial-scale
    climate variability and regional differences in summer moisture.
    At regional scales, sites in present-day summer-dry areas show a
    period of protracted high fire activity within the early Holocene
    that is attributed to intensified summer drought in the summer-dry
    region. Sites in summer-wet areas show the opposite pattern, that
    fire was lower in frequency than present in the early Holocene as
    result of strengthened monsoonal circulation then. Higher fire-episode
    frequency at many sites in the last 2000 years is attributed to greater
    drought during the Medieval Climate Anomaly and possibly anthropogenic
    burning. The association between drought, increased fire occurrence,
    and available fuels evident on several time scales suggests that
    long-term fire history patterns should be considered in current assessments
    of historical fire regimes and fuel conditions.
    BibTeX:
    @article{Whitlock2008,
      author = {Whitlock, C and Marlon, J and Briles, C and Brunelle, A and Long, C and Bartlein, P},
      title = {Long-term relations among fire, fuel, and climate in the north-western US based on lake-sediment studies},
      journal = {International Journal of Wildland Fire},
      year = {2008},
      volume = {17},
      number = {1},
      pages = {72--83}
    }
    					
    Bigler2007 Bigler, C.; Gavin, D.G.; Gunning, C. & Veblen, T.T. Drought induces lagged tree mortality in a subalpine forest in the Rocky Mountains 2007 Oikos
    Vol. 116 (12) , pp. 1983-1994  
    article
    Abstract: Extreme climatic events are key factors in initiating gradual or sudden
    changes in forest ecosystems through the promotion of severe, tree-killing
    disturbances such as fire, blowdown, and widespread insect outbreaks.
    In contrast to these climatically-incited disturbances, little is
    known about the more direct effect of drought on tree mortality,
    especially in high-elevation forests. Therefore projections of drought-induced
    mortality under future climatic conditions remain uncertain. For
    a subalpine forest landscape in the Rocky Mountains of northern Colorado
    (USA), we quantified lag effects of drought on mortality of Engelmann
    spruce Picea engelmannii, subalpine fir Abies lasiocarpa, and lodgepole
    pine Pinus contorta. For the period 1910-2004, we related death dates
    of 164 crossdated dead trees to early-season and late-season droughts.
    Following early-season droughts, spruce mortality increased over
    five years and fir mortality increased sharply over 11 years. Following
    late-season droughts, spruce showed a small increase in mortality
    within one year, whereas fir showed a consistent period of increased
    mortality over two years. Pine mortality was not affected by drought.
    Low pre-drought radial growth rates predisposed spruce and fir to
    drought-related mortality. Spruce and fir trees that died during
    a recent drought (2000-2004) had significantly lower pre-drought
    growth rates than live neighbour trees. Overall, we found large interspecific
    differences in drought-related mortality with fir showing the strongest
    effect followed by spruce and pine. This direct influence of climatic
    variability on differential tree mortality has the potential for
    driving large-scale changes in subalpine forests of the Rocky Mountains.
    BibTeX:
    @article{Bigler2007,
      author = {Bigler, C and Gavin, DG and Gunning, C and Veblen, TT},
      title = {Drought induces lagged tree mortality in a subalpine forest in the Rocky Mountains},
      journal = {Oikos},
      year = {2007},
      volume = {116},
      number = {12},
      pages = {1983--1994}
    }
    					
    Gavin2007 Gavin, D.G.; Hallett, D.J.; Hu, F.S.; Lertzman, K.P.; Prichard, S.J.; Brown, K.J.; Lynch, J.A.; Bartlein, P. & Peterson, D.L. Forest fire and climate change in western North America: insights from sediment charcoal records 2007 Frontiers in Ecology and the Environment
    Vol. 5 (9) , pp. 499-506  
    article
    Abstract: Millennial-scale records of forest fire provide important baseline
    information for ecosystem management, especially in regions with
    too few recent fires to describe the historical range of variability.
    Charcoal records from lake sediments and soil profiles are well suited
    for reconstructing the incidence of past fire and its relationship
    to changing climate and vegetation. We highlight several records
    from western North America and their relevance in reconstructing
    historical forest dynamics, fire-climate relationships, and feedbacks
    between vegetation and fire under climate change. Climatic effects
    on fire regimes are evident in many regions, but comparisons of paleo-fire
    records sometimes show a lack of synchrony, indicating that local
    factors substantially affect fire occurrence, even over long periods.
    Furthermore, the specific impacts of vegetation change on fire regimes
    vary among regions with different vegetation histories. By documenting
    the effects on fire patterns of major changes in climate and vegetation,
    paleo-fire records can be used to test the mechanistic models required
    for the prediction of future variations in fire.
    BibTeX:
    @article{Gavin2007,
      author = {Gavin, DG and Hallett, DJ and Hu, FS and Lertzman, KP and Prichard, SJ and Brown, KJ and Lynch, JA and Bartlein, P and Peterson, DL},
      title = {Forest fire and climate change in western North America: insights from sediment charcoal records},
      journal = {Frontiers in Ecology and the Environment},
      year = {2007},
      volume = {5},
      number = {9},
      pages = {499--506}
    }
    					
    Higuera2007 Higuera, P.E.; Peters, M.E.; Brubaker, L.B. & Gavin, D.G. Understanding the origin and analysis of sediment-charcoal records with a simulation model 2007 Quaternary Science Reviews
    Vol. 26 (13-14) , pp. 1790-1809  
    article
    Abstract: Interpreting sediment-charcoal records is challenging because there
    is little information linking charcoal production from fires to charcoal
    accumulation in lakes. We present a numerical model simulating the
    major processes involved in this pathway. The model incorporates
    the size, location, and frequency of fires, primary and secondary
    charcoal transport, sediment mixing, and sediment sampling. We use
    the model as a tool to evaluate assumptions of charcoal dispersal
    and taphonomy and to assess the merits of inferring local and regional
    fire history by decomposing charcoal records into low-frequency ('background')
    and high-frequency ('peak') components. Under specific dispersal
    scenarios, the model generates records similar in appearance to sediment-charcoal
    records from Alaskan boreal forests. These scenarios require long-distance
    dispersal (e.g. 10(0)-10(1) km), consistent with observations from
    wildfires but longer than previously inferred from experimental dispersal
    data. More generally, charcoal accumulation in simulated records
    mainly reflects area burned within the charcoal source area. Variability
    in charcoal peak heights is primarily explained by the size of charcoal
    source areas relative to the size of simulated fires, with an increase
    in this ratio resulting in increased variability in peak heights.
    Mixing and multi-year sampling add noise to charcoal records, obscuring
    the relationship between area burned and charcoal accumulation. This
    noise highlights the need for statistical treatments of charcoal
    records. Using simulated records we demonstrate that long-term averages
    of charcoal accumulation (> 10 x mean fire return interval) correlate
    well with area burned within the entire charcoal source area. We
    further demonstrate how decomposing simulated records to isolate
    the peak component emphasizes fire occurrence at smaller spatial
    scales (< 1 km radius), despite the importance of long-distance charcoal
    dispersal in simulating charcoal records similar to observations.
    Together, these results provide theoretical support for the analysis
    of charcoal records using the decomposition approach. (C) 2007 Elsevier
    Ltd. All rights reserved.
    BibTeX:
    @article{Higuera2007,
      author = {Higuera, PE and Peters, ME and Brubaker, LB and Gavin, DG},
      title = {Understanding the origin and analysis of sediment-charcoal records with a simulation model},
      journal = {Quaternary Science Reviews},
      year = {2007},
      volume = {26},
      number = {13-14},
      pages = {1790--1809}
    }
    					
    Long2007 Long, C.J.; Whitlock, C. & Bartlein, P.J. Holocene vegetation and fire history of the Coast Range, western Oregon, USA 2007 Holocene
    Vol. 17 (7) , pp. 917-926  
    article
    Abstract: Pollen and high-resolution charcoal records from three lakes were
    examined to reconstruct the vegetation and fire history of the Oregon
    Coast Range for the last 9000 years. The sites are located along
    a north-to-south effective precipitation gradient and changes in
    vegetation and fire activity provided information on the nature of
    this gradient in the past. The relation of vegetation to climate
    change was examined at millennial timescales and the relation between
    fire and climate was examined on centennial timescales by comparing
    fire-interval distribution and fire synchrony between sites. The
    pollen data indicate more fire-adapted vegetation during the early-Holocene
    period (c. 9000 to 6700 cal. yr BP), followed by a shift to forests
    with more fire-sensitive taxa in the mid Holocene (c. 6700 cal. yr
    BP to 2700 cal. yr BP) and modern forest assemblages developing over
    the last c. 2700 years. Comparisons of fire-interval distributions
    showed that the time between fires was similar between two of the
    three combinations of sites, suggesting that the moisture gradient
    has played an important role in determining long-term fire frequency.
    However, century-scale synchrony of fire occurrence between the two
    sites with the largest difference in effective precipitation suggests
    that centennial-scale shifts in climate may have overcome the environmental
    differences between these locations. Asynchrony in fire occurrence
    between the sites with more similar effective precipitation implies
    that local conditions may have played an important role in determining
    fire synchrony between sites with similar long-term climate histories.
    BibTeX:
    @article{Long2007,
      author = {Long, CJ and Whitlock, C and Bartlein, PJ},
      title = {Holocene vegetation and fire history of the Coast Range, western Oregon, USA},
      journal = {Holocene},
      year = {2007},
      volume = {17},
      number = {7},
      pages = {917--926}
    }
    					
    Marcus2007a Marcus, W.A.; Meacham, J.E.; Rodman, A. & Steingisser, A. Visual Fields: Atlas of Yellowstone – preliminary work 2007 Cartographic Perspectives
    Vol. 57 , pp. 86-87  
    article
    BibTeX:
    @article{Marcus2007a,
      author = {Marcus, WA and Meacham, JE and Rodman, A and Steingisser, A},
      title = {Visual Fields: Atlas of Yellowstone – preliminary work},
      journal = {Cartographic Perspectives},
      year = {2007},
      volume = {57},
      pages = {86-87}
    }
    					
    Minckley2007 Minckley, T.A.; Whitlock, C. & Bartlein, P.J. Vegetation, fire, and climate history of the northwestern Great Basin during the last 14,000 years 2007 Quaternary Science Reviews
    Vol. 26 (17-18) , pp. 2167-2184  
    article
    Abstract: The northwestern Great Basin lies in the transition zone between the
    mesic Pacific Northwest and xeric intermountain West. The paleoenvironruental
    history based on pollen, macroscopic charcoal, and plant macrofossils
    from three sites in the northwestern Great Basin was examined to
    understand the relationships among the modern vegetation, fire disturbance
    and climate. The vegetation history suggests that steppe and open
    forest communities were present at high elevations from ca 11,000
    to 7000 cal yr BP, and were replaced by forests composed of white
    fir, western white pine, and whitebark pine in the late Holocene.
    Over the last 11,000 years, fires were more frequent in tuid-elevation
    forests (10-25 fire episodes/1000 years) and rare in high-elevation
    forests (2-5 fire episodes/1000 years). Applying modern pollen-climate
    relationships to the fossil pollen spectra provided a means to interpret
    past climate changes in this region. In the past 9000 years summer
    temperatures decreased from 1 to 4 C, and annual precipitation has
    increased 7-15%. These results indicate that the millennial-scale
    climate forcing driving vegetation changes can be quantified within
    the intermountain West in general and northwestern Great Basin in
    particular. In addition, fire call be considered an important component
    of these ecosystems, but it does not appear to be a forcing mechanism
    for vegetation change at the resolution of these records. (c) 2007
    Elsevier Ltd. All rights reserved.
    BibTeX:
    @article{Minckley2007,
      author = {Minckley, TA and Whitlock, C and Bartlein, PJ},
      title = {Vegetation, fire, and climate history of the northwestern Great Basin during the last 14,000 years},
      journal = {Quaternary Science Reviews},
      year = {2007},
      volume = {26},
      number = {17-18},
      pages = {2167--2184}
    }
    					
    Murray2007 Murray, B. & Fonstad, M.A. Preface: Complexity (and simplicity) in landscapes 2007 Geomorphology
    Vol. 91 (3-4) , pp. 173-177  
    article binghamton geomorphology symposium, complex systems, criticality, emergence, geomorphology, morphodynamics, nonlinear dynamics, scaling, self-organization, self-organized criticality, systems
    BibTeX:
    @article{Murray2007,
      author = {Murray, Brad and Fonstad, Mark A.},
      title = {Preface: Complexity (and simplicity) in landscapes},
      journal = {Geomorphology},
      year = {2007},
      volume = {91},
      number = {3-4},
      pages = {173--177},
      doi = {http://doi.org/10.1016/j.geoinorph.2007.07.011}
    }
    					
    Parsons2007 Parsons, J.A. & Fonstad, M.A. A cellular automata model of surface water flow 2007 Hydrological Processes
    Vol. 21 (16) , pp. 2189-2195  
    article calibration, cellular automata, distributed models, river-basin, surface water hydrology
    Abstract: Previous cellular automata models of surface water flow have been
    constructed to reflect steady, gradually-varied flow conditions.
    While these models are extremely important in showing the near-equilibrium
    forms that result from the interactions of water and boundary material,
    highly dynamic forms and processes require models that represent
    unsteady flow conditions. In order to simulate unsteady flow in a
    cellular model of surface water flow, the conservation of mass and
    the Manning's equations are coupled with an algorithm to delay the
    movement of water from one pixel to the next until the correct timing
    is reached. This approach yields highly realistic flood wave hydrographs
    when compared with flood observations in the Walnut Gulch Experiment
    Watershed. Coupling this unsteady flow model with simple laws of
    sediment erosion, transport, and deposition should allow event-based
    simulations of watershed and river channel geomorphologic change.
    Copyright (c) 2007 John Wiley & Sons, Ltd.
    BibTeX:
    @article{Parsons2007,
      author = {Parsons, Jay A. and Fonstad, Mark A.},
      title = {A cellular automata model of surface water flow},
      journal = {Hydrological Processes},
      year = {2007},
      volume = {21},
      number = {16},
      pages = {2189--2195},
      doi = {http://doi.org/10.1002/hyp.6587}
    }
    					
    Shuman2007 Shuman, B.; Bartlein, P.J. & Webb, T. Response to "Comments on: 'The magnitude of millennial-and orbital-scale climatic change in eastern North America during the Late-Quaternary' by Shuman et al." 2007 Quaternary Science Reviews
    Vol. 26 (1-2) , pp. 268-273  
    article
    BibTeX:
    @article{Shuman2007,
      author = {Shuman, B and Bartlein, PJ and Webb, T},
      title = {Response to "Comments on: 'The magnitude of millennial-and orbital-scale climatic change in eastern North America during the Late-Quaternary' by Shuman et al."},
      journal = {Quaternary Science Reviews},
      year = {2007},
      volume = {26},
      number = {1-2},
      pages = {268--273}
    }
    					
    Whitlock2007 Whitlock, C.; Moreno, P.I. & Bartlein, P. Climatic controls of Holocene fire patterns in southern South America 2007 Quaternary Research
    Vol. 68 (1) , pp. 28-36  
    article
    Abstract: Holocene fire-climate-vegetation linkages are mostly understood at
    individual sites by comparing charcoal and pollen records with other
    paleoenvironmental proxy and model simulations. This scale of reconstruction
    often obscures detection of large-scale patterns in past fire activity
    that are related to changes in regional climate and vegetation. A
    network of 31 charcoal records from southern South America was examined
    to assess fire history along a transect from subtropic to subantarctic
    biomes. The charcoal data indicate that fire activity was greater
    than present at ca. 12,000 cal yr BP and increased further and was
    widespread at 9500 cal yr BR Fire activity decreased and became more
    spatially variable by 6000 cal yr BP, and this trend continued to
    present. Atmospheric circulation anomalies during recent high-fire
    years show a southward shift in westerlies, and paleoclimate model
    simulations and data syntheses suggest that such conditions may have
    prevailed for millennia in the early Holocene when the pole-to-equator
    temperature gradients were weaker and annual temperatures were higher
    than present, in response to orbitaltime-scale insolation changes.
    (c) 2007 University of Washington. All rights reserved.
    BibTeX:
    @article{Whitlock2007,
      author = {Whitlock, C and Moreno, PI and Bartlein, P},
      title = {Climatic controls of Holocene fire patterns in southern South America},
      journal = {Quaternary Research},
      year = {2007},
      volume = {68},
      number = {1},
      pages = {28--36}
    }
    					
    Diffenbaugh2006 Diffenbaugh, N.S.; Ashfaq, M.; Shuman, B.; Williams, J.W. & Bartlein, P.J. Summer aridity in the United States: Response to mid-Holocene changes in insolation and sea surface temperature 2006 Geophysical Research Letters
    Vol. 33 (22) , pp. -  
    article
    Abstract: We examine the response of summer precipitation to mid-Holocene insolation
    forcing and insolation-induced changes in sea surface temperature.
    Using a high-resolution nested climate modeling system, we find that
    mid-Holocene insolation forcing results in drier-than-present conditions
    over the central continental United States ( U. S.) and northern
    Rocky Mountains, as well as wetter-than-present conditions over the
    Atlantic seaboard and northwestern Great Plains. We find that changes
    in summer precipitation are dominated by changes in large-scale processes,
    with similar patterns of change in the global and nested models.
    We also find that insolation-induced changes in sea surface temperature
    do not change the basic pattern of precipitation response, primarily
    because the dynamical response is very similar with and without sea
    surface temperature changes. Notably, drier-than-present conditions
    over the central U. S. are associated with enhanced anticyclonic
    circulation aloft over the mid-continent and reduced low-level moisture
    content over the Gulf of Mexico and south-central U. S., while wetter-than-present
    conditions over the Atlantic seaboard are associated with enhanced
    low-level cyclonic circulation and elevated low-level moisture content.
    The simulated patterns of precipitation and soil moisture agree with
    proxy moisture records from most regions, indicating both that insolation
    was the strongest determinant of mid-Holocene summer aridity in the
    continental U. S. and that high-resolution nested climate modeling
    systems are able to capture the basic response of midlatitude warm-season
    aridity to changes in external climate forcing.
    BibTeX:
    @article{Diffenbaugh2006,
      author = {Diffenbaugh, NS and Ashfaq, M and Shuman, B and Williams, JW and Bartlein, PJ},
      title = {Summer aridity in the United States: Response to mid-Holocene changes in insolation and sea surface temperature},
      journal = {Geophysical Research Letters},
      year = {2006},
      volume = {33},
      number = {22},
      pages = {--}
    }
    					
    Fonstad2006 Fonstad, M.A. Cellular automata as analysis and synthesis engines at the geomorphology-ecology interface 2006 Geomorphology
    Vol. 77 (3-4) , pp. 217-234  
    article cellular automata, competition, debris flows, differential-equations, ecology, fire, geomorphology, lattice-gas, model, modeling, pattern, self-organized criticality, simulation, spatial dynamics
    Abstract: The linkages between ecology and geomorphology can be difficult to
    identify because of physical complexity and the limitations of the
    current theoretical representations in these two fields of study.
    Deep divisions between these disciplines are manifest in the methods
    used to simulate process, such as rigidly physical-deterministic
    methods for many aspects of geomorphology compared with purely stochastic
    simulations in many models of change in landcover. Practical and
    theoretical research into ecology-geomorphology linkages cannot wait
    for a single simulation schema which may never come; as a result,
    studies of these linkages often appear disjointed and inconsistent.
    The grid-based simulation framework for cellular automata (CA)
    allows simultaneous use of competing schemas. CA use in general
    geographic studies has been primarily limited to urban simulations
    models of change for land cover, both highly stochastic and/or expert
    rule-based. In the last decade, however, methods for describing physically
    deterministic systems in the CA framework have become much more
    accurate. The possibility now exists to merge separate CA simulations
    of different environmental systems into unified "multiautomata" models.
    Because CAs allow transition rules that are deterministic, probabilistic,
    or expert rule-based, they can immediately incorporate the existing
    knowledge rules in ecology and geomorphology. The explicitly spatial
    nature of CA provides a map-like framework that should allow a
    simple and deeply rooted connection with the mapping traditions of
    the geosciences and ecological sciences. (c) 2006 Elsevier B.V.
    All rights reserved.
    BibTeX:
    @article{Fonstad2006,
      author = {Fonstad, Mark A.},
      title = {Cellular automata as analysis and synthesis engines at the geomorphology-ecology interface},
      journal = {Geomorphology},
      year = {2006},
      volume = {77},
      number = {3-4},
      pages = {217--234},
      doi = {http://doi.org/10.1016/j.geomorph.2006.01.006}
    }
    					
    Gavin2006 Gavin, D.G. & Hu, F.S. Spatial variation of climatic and non-climatic controls on species distribution: the range limit of Tsuga heterophylla 2006 Journal of Biogeography
    Vol. 33 (8) , pp. 1384-1396  
    article
    Abstract: Aim: To assess which climatic variables control the distribution of
    western hemlock (Tsuga heterophylla), how climatic controls vary
    over latitude and between disjunct coastal and interior sub-distributions,
    and whether non-climatic factors, such as dispersal limitation and
    interspecific competition, affect range limits in areas of low climatic
    control. Location: North-western North America. Methods:We compared
    four bioclimatic variables [actual evapotranspiration (AET), water
    deficit (DEF), mean temperature of the coldest month (MTCO), and
    growing degree-days (GDD5)] with the distribution of T. heterophylla
    at a 2-km grid cell resolution. The distribution is based on a zonal
    ecosystem classification where T. heterophylla is the dominant late-successional
    species. For each bioclimatic variable and at each degree of latitude,
    we calculated the threshold that best defines the T. heterophylla
    distribution and assessed the extent to which T. heterophylla was
    segregated to one end of the bioclimatic gradient. We also fitted
    two forms of multivariate bioclimatic models to predict the T. heterophylla
    distribution: a simple threshold model and a complex Gaussian mixture
    model. Each model was trained separately on the coastal and interior
    distributions, and predicted areas outside of the T. heterophylla
    distribution (overprediction) were evaluated with respect to known
    outlier populations. Results: Actual evapotranspiration was the most
    accurate predictor across the T. heterophylla distribution; other
    variables were important only in certain areas. There was strong
    latitudinal variation in the thresholds of all variables except AET,
    and the interior distribution had wider bioclimatic thresholds than
    the coastal distribution. The coastal distribution was predicted
    accurately by both bioclimatic models; areas of overprediction rarely
    occurred > 10 km from the observed distribution and generally matched
    small outlier populations. In contrast, the interior distribution
    was poorly predicted by both models; areas of overprediction occurred
    up to 140 km from the observed distribution and did not match outlier
    populations. The greatest overprediction occurred in Idaho and Montana
    in areas supporting species that typically co-exist with T. heterophylla.
    Main conclusions: The high predictive capacity of AET is consistent
    with this species' physiological requirements for a mild and humid
    climate. Spatial variation of MTCO, GDD5 and DEF thresholds probably
    reflects both the correlation of these variables with AET and ecotypic
    variation. The level of overprediction in portions of the interior
    suggests that T. heterophylla has not completely expanded into its
    potential habitat. Tsuga heterophylla became common in the interior
    2000-3500 years ago, compared with > 9000 years ago in the coastal
    region. The limited time for dispersal, coupled with frequent fires
    at the margins of the distribution and competition with disturbance-adapted
    species, may have retarded range expansion in the interior. This
    study demonstrates that bioclimatic modelling can help identify various
    climatic and non-climatic controls on species distributions.
    BibTeX:
    @article{Gavin2006,
      author = {Gavin, DG and Hu, FS},
      title = {Spatial variation of climatic and non-climatic controls on species distribution: the range limit of Tsuga heterophylla},
      journal = {Journal of Biogeography},
      year = {2006},
      volume = {33},
      number = {8},
      pages = {1384--1396}
    }
    					
    Gavin2006a Gavin, D.G.; Hu, F.S.; Lertzman, K. & Corbett, P. Weak climatic control of stand-scale fire history during the late Holocene 2006 Ecology
    Vol. 87 (7) , pp. 1722-1732  
    article
    Abstract: Forest fire occurrence is affected by multiple controls that operate
    at local to regional scales. At the spatial scale of forest stands,
    regional climatic controls may be obscured by local controls (e.g.,
    stochastic ignitions, topography, and fuel loads), but the long-term
    role of such local controls is poorly understood. We report here
    stand-scale (< 100 ha) fire histories of the past 5000 years based
    on the analysis of sediment charcoal at two lakes I I km apart in
    southeastern British Columbia. The two lakes are today located in
    similar subalpine forests, and they likely have experienced the same
    late-Holocene climatic. changes because of their close proximity.
    We evaluated two independent properties of fire history: (1) fire-interval
    distribution, a measure of the overall incidence of fire, and (2)
    fire synchroneity, a measure of the co-occurrence of fire (here,
    assessed at centennial to millennial time scales due to the resolution
    of sediment records). Fire-interval distributions differed between
    the sites prior to, but not after, 2500 yr before present. When the
    entire 5000-yr period is considered, no statistical synchrony between
    fire-episode dates existed between the two sites at any temporal
    scale, but for the last 2500 yr marginal levels of synchrony occurred
    at centennial scales. Each individual fire record exhibited little
    coherency with regional climate changes. In contrast, variations
    in the composite record (average of both sites) matched variations
    in climate evidenced by late-Holocene glacial advances. This was
    probably due to the increased sample size and spatial extent represented
    by the composite record (up to 200 ha) plus increased regional climatic
    variability over the last several millennia, which may have partially
    overridden local, non-climatic controls. We conclude that (1) over
    past millennia, neighboring stands with similar modern conditions
    may have experienced different fire intervals and asynchronous patterns
    in fire episodes, likely because local controls outweighed the synchronizing
    effect of climate; (2) the influence of climate on fire occurrence
    is more strongly expressed when climatic variability is relatively
    great; and (3) multiple records from a region are essential if climate-fire
    relations are to be reliably described.
    BibTeX:
    @article{Gavin2006a,
      author = {Gavin, DG and Hu, FS and Lertzman, K and Corbett, P},
      title = {Weak climatic control of stand-scale fire history during the late Holocene},
      journal = {Ecology},
      year = {2006},
      volume = {87},
      number = {7},
      pages = {1722--1732}
    }
    					
    Hughes2006 Hughes, M.L.; McDowell, P.F. & Marcus, W.A. Accuracy assessment of georectified aerial photographs: Implications for measuring lateral channel movement in a GIS 2006 Geomorphology
    Vol. 74 (1-4) , pp. 1-16  
    article fluvial geomorphology
    Abstract: Aerial photographs are commonly used to measure planform river channel
    change. We investigated the sources and implications of georectification
    error in the measurement of lateral channel movement by testing how
    the number (6-30) and type (human versus natural landscape features)
    of ground-control points (GCPs) and the order of the transformation
    polynomial (first-, second-, and third-order) affected the spatial
    accuracy of a typical georectified aerial photograph. Error was assessed
    using the root-mean-square error (RMSE) of the GCPs as well as error
    in 31 independent test points. The RMSE and the mean and median values
    of test-point errors were relatively insensitive to the number of
    GCPs above eight, but the upper range of test-point errors showed
    marked improvement (i.e., the number of extreme errors was reduced)
    as more GCPS were used for georectification. Using more GCPs thus
    improved overall georectification accuracy, but this improvement
    was not indicated by the RMSE, suggesting that independent test-points
    located in key areas of interest should be used in addition to RSME
    to evaluate georectification error. The order of the transformation
    polynomial also influenced test-point accuracy; the second-order
    polynomial function yielded the best result for the terrain of the
    study area. GCP type exerted a less consistent influence on test-point
    accuracy, suggesting that although hard-edged points (e.g., roof
    comers) are favored as GCPs, some soft-edged points (e.g., trees)
    may be used without adding significant error. Based upon these results,
    we believe that aerial photos of a floodplain landscape similar to
    that of our study can be consistently georectified to an accuracy
    of approximately +/- 5 m, with similar to 10% chance of greater error.
    The implications of georectification error for measuring lateral
    channel movement are demonstrated with a multiple buffer analysis,
    which documents the inverse relationship between the size of the
    buffers applied to two channel centerlines and the magnitude of change
    detected between them. This study demonstrates the importance of
    using an independent test-point analysis in addition to the RSME
    to evaluate and treat locational error in channel change studies.
    (c) 2005 Published by Elsevier B.V.
    BibTeX:
    @article{Hughes2006,
      author = {Hughes, ML and McDowell, PF and Marcus, WA},
      title = {Accuracy assessment of georectified aerial photographs: Implications for measuring lateral channel movement in a GIS},
      journal = {Geomorphology},
      year = {2006},
      volume = {74},
      number = {1-4},
      pages = {1--16}
    }
    					
    James2006 James, L.A. & Marcus, W.A. The 2006 Binghamton Geomorphology Symposium on The Human Role in Changing Fluvial Systems - Preface 2006 Geomorphology
    Vol. 79 (3-4) , pp. 144-147  
    article fluvial geomorphology
    BibTeX:
    @article{James2006,
      author = {James, LA and Marcus, WA},
      title = {The 2006 Binghamton Geomorphology Symposium on The Human Role in Changing Fluvial Systems - Preface},
      journal = {Geomorphology},
      year = {2006},
      volume = {79},
      number = {3-4},
      pages = {144--147}
    }
    					
    James2006a James, L.A. & Marcus, W.A. The human role in changing fluvial systems: Retrospect, inventory and prospect 2006 Geomorphology
    Vol. 79 (3-4) , pp. 152-171  
    article
    Abstract: Historical and modern scientific contexts are provided for the 2006
    Binghamton Geomorphology Symposium on the Human Role in Changing
    Fluvial Systems. The 2006 symposium provides a synthesis of research
    concerned with human impacts on fluvial systems - including hydrologic
    and geomorphic changes to watersheds - while also commemorating the
    50th anniversary of the 1955 Man's Role in Changing the Face of the
    Earth Symposium [Thomas, Jr., W. L. (Ed.), 1956a. Man's Role in Changing
    the Face of the Earth. Univ. Chicago Press, Chicago. 1193 pp]. This
    paper examines the 1955 symposium from the perspective of human impacts
    on rivers, reviews current inquiry on anthropogenic interactions
    in fluvial systems, and anticipates future directions in this field.
    Although the 1955 symposium did not have an explicit geomorphic focus,
    it set the stage for many subsequent anthropogeomorphic studies.
    The 1955 conference provided guidance to geomorphologists by recommending
    and practicing interdisciplinary scholarship, through the use of
    diverse methodologies applied at extensive temporal and geographical
    scales, and through its insistence on an integrated understanding
    of human interactions with nature. Since 1956, research on human
    impacts to fluvial systems has been influenced by fundamental changes
    in why the research is done, what is studied, how river studies are
    conducted, and who does the research. Rationales for river research
    are now driven to a greater degree by institutional needs, environmental
    regulations, and aquatic restoration. New techniques include a host
    of dating, spatial imaging, and ground measurement methods that can
    be coupled with analytical functions and digital models. These new
    methods have led to a greater understanding of channel change, variations
    across multiple temporal and spatial scales, and integrated watershed
    perspectives; all changes that are reflected by the papers in this
    volume. These new methods also bring a set of technical demands for
    the training of geomorphologists. The 2006 Binghamton Geomorphology
    Symposium complements the 1956 symposium by providing a more specific
    and updated view of river systems coupled with human interactions.
    The symposium focuses on linkages between human land use, structures,
    and channel modification with geomorphology, hydrology, and ecology.
    The emergence of sustainability as a central policy guideline in
    environmental management should generate greater interest in geomorphic
    perspectives, especially as they pertain to human activities. The
    lack of theories of anthropogeomorphic change, however, presents
    a challenge for the next generation of geomorphologists in this rapidly
    growing subfield. (c) 2006 Elsevier B.V. All rights reserved.
    BibTeX:
    @article{James2006a,
      author = {James, LA and Marcus, WA},
      title = {The human role in changing fluvial systems: Retrospect, inventory and prospect},
      journal = {Geomorphology},
      year = {2006},
      volume = {79},
      number = {3-4},
      pages = {152--171}
    }
    					
    Marlon2006 Marlon, J.; Bartlein, P.J. & Whitlock, C. Fire-fuel-climate linkages in the northwestern USA during the Holocene 2006 Holocene
    Vol. 16 (8) , pp. 1059-1071  
    article
    Abstract: Variations in fire regimes can be inferred from changes in the abundance
    of sedimentary charcoal found in lake and bog sediments. When analysed
    with pollen data, inferences can be made about past vegetation dynamics
    and climate as well. The analysis of high-resolution charcoal records
    generally involves the decomposition of charcoal influx into (a)
    a slowly varying 'background' component that provides information
    about long-term changes in regional fire activity, biomass and/or
    depositional processes, and (b) a 'peaks' component that represents
    local fire events. In this study, 15 high-resolution charcoal records
    from the northwestern USA and associated pollen data were examined
    to describe the variations and controls of charcoal influx and background
    trends. Late-Holocene charcoal influx levels at each site were compared
    with late-Holocene sedimentation rates, vegetation and fire frequency,
    and with modern climate and physical site characteristics to better
    understand the spatial variability in charcoal abundance. Charcoal
    abundance was largely determined by physical site characteristics
    (eg, lake and watershed size) and the proportion of woody taxa. Background
    trends displayed regional similarities, - closely with woody taxa
    proportions in and the subcontinental scale trend based on all records
    correlated the pollen spectra. Background charcoal and woody taxa
    proportions increased together from minima in the Late Glacial to
    maxima in the late Holocene. The strong similarity in these trends
    suggests that background charcoal influx is a function of fuel characteristics,
    which in turn are governed by climate and vegetation. Variations
    in sedimentation rate and fire frequency had little influence on
    background charcoal trends.
    BibTeX:
    @article{Marlon2006,
      author = {Marlon, J and Bartlein, PJ and Whitlock, C},
      title = {Fire-fuel-climate linkages in the northwestern USA during the Holocene},
      journal = {Holocene},
      year = {2006},
      volume = {16},
      number = {8},
      pages = {1059--1071}
    }
    					
    Power2006 Power, M.J.; Whitlock, C.; Bartlein, P. & Stevens, L.R. Fire and vegetation history during the last 3800 years in northwestern Montana 2006 Geomorphology
    Vol. 75 (3-4) , pp. 420-436  
    article
    Abstract: Foy Lake in northwestern Montana provides a record of annual-to-decadal-scale
    landscape change. Sedimentary charcoal and pollen analyses were used
    to document fire and vegetation changes over the last 3800 years,
    which were then compared to similar records from AD 1880 to 2000.
    The long-term record at Foy Lake suggests shifts between forest and
    steppe as well as changes in fire regime that are likely the result
    of climate change. Fire activity (inferred from the frequency of
    charcoal peaks) averaged 18 fire episodes/1000 years from 3800 to
    2125 cal year BP, and increased from 16 fire episodes/1000 years
    at 2125 cal year BP to 22 episodes/1000 years at 750 cal year BP,
    a period when the pollen data suggest that steppe vegetation yielded
    to increasing patches of forest cover. Between 2125 and 750 cal year
    BP, increased forest cover produced more background charcoal than
    before and after this period, when vegetation was dominated by steppe.
    Between 750 and 75 cal year BP steppe has expanded and fire episode
    frequency averaged 33 episodes/1000 years, increasing to a maximum
    of 40 episodes/1000 years at ca. 300 cal year BP and then decreasing
    to present levels. Since AD 1880, the pollen record indicates an
    increase in shrubs and grasses from AD 1895 to 1960 as a result of
    vegetation changes associated with timber harvesting and livestock
    grazing. No fires have been documented in the Foy Lake watershed
    since AD 1880. Charcoal from the extralocal fires of AD 1910, burning
    over 4,111,249 ha in Idaho, Montana, and Wyoming, however, is present
    in Foy Lake. Between AD 1970 and 2000, increased arboreal pollen
    in the record is consistent with observations that the forest has
    become more closed. The activities of Euro-Americans have led to
    a decline in forest cover between AD 1880 and 1970, followed by a
    recent increase as trees are now growing in areas previously occupied
    by steppe. Euro-Americans are likely the cause of a reduction in
    fire activity in watershed since AD 1880. (c) 2005 Elsevier B.V.
    All rights reserved.
    BibTeX:
    @article{Power2006,
      author = {Power, MJ and Whitlock, C and Bartlein, P and Stevens, LR},
      title = {Fire and vegetation history during the last 3800 years in northwestern Montana},
      journal = {Geomorphology},
      year = {2006},
      volume = {75},
      number = {3-4},
      pages = {420--436}
    }
    					
    Shinker2006 Shinker, J.J.; Bartlein, P.J. & Shuman, B. Synoptic and dynamic climate controls of North American mid-continental aridity 2006 Quaternary Science Reviews
    Vol. 25 (13-14) , pp. 1401-1417  
    article
    Abstract: The mid-continent of North America was likely drier than present during
    the mid-Holocene, based on inferences from fossil-pollen data and
    estimates of past lake levels. Mid-Holocene dry conditions have often
    been explained by increases in the dominance (frequency and/or duration)
    of Pacific airmasses, zonal flow patterns, or enhanced westerlies.
    We analyzed modern episodes between 1959 and 1997 when westerly flow
    was anomalously strong (an indication of zonal flow) to determine
    if zonal flow is associated with drier-than-normal conditions in
    the mid-continent. In contrast to that expectation, composite-anomaly
    patterns of 500mb geopotential heights show similar meridional, as
    opposed to zonal, patterns for both anomalously dry and anomalously
    wet years, suggesting that large-scale circulation patterns alone
    may not provide a full explanation of surface-moisture anomalies.
    Anomalous moisture conditions in the midcontinent at present develop
    due to the dynamic interplay between surface conditions and atmospheric
    processes. Consideration of both moisture availability (determined
    by atmospheric moisture flux and soil-moisture recycling) and mechanisms
    for enhancing or suppressing precipitation (vertical motions in the
    atmosphere) is therefore required to describe the establishment of
    anomalously dry or wet conditions in the region today, as well as
    during the mid-Holocene. (c) 2006 Elsevier Ltd. All rights reserved.
    BibTeX:
    @article{Shinker2006,
      author = {Shinker, JJ and Bartlein, PJ and Shuman, B},
      title = {Synoptic and dynamic climate controls of North American mid-continental aridity},
      journal = {Quaternary Science Reviews},
      year = {2006},
      volume = {25},
      number = {13-14},
      pages = {1401--1417}
    }
    					
    Whitlock2006 Whitlock, C.; Bianchi, M.M.; Bartlein, P.J.; Markgraf, V.; Marlon, J.; Walsh, M. & McCoy, N. Postglacial vegetation, climate, and fire history along the east side of the Andes (lat 41-42.5 degrees S), Argentina 2006 Quaternary Research
    Vol. 66 (2) , pp. 187-201  
    article
    Abstract: The history of the low-elevation forest and forest-steppe ecotone
    on the east side of the Andes is revealed in pollen and charcoal
    records obtained from mid-latitude lakes. Prior to 15,000 cat yr
    BP, the vegetation was characterized by steppe vegetation with isolated
    stands of Nothofagus. The climate was generally dry, and the sparse
    vegetation apparently lacked sufficient fuels to burn extensively.
    After 15,000 cat yr BP, a mixture of Nothofagus forest and shrubland/steppe
    developed. Fire activity increased between 13,250 and 11,400 cat
    yr BP, contemporaneous with a regionally defined cold dry period
    (Huelmo/Maseardi Cold Reversal). The early-Holocene period was characterized
    by an open Nothofagus forest/shrubland mosaic, and fire frequency
    was high in dry sites and low in wet sites; the data suggest a sharp
    decrease in moisture eastward from the Andes. A shift to a surface-fire
    regime occurred at 7500 cat yr BP at the wet site and at 4400 cat
    yr BP at the dry site, preceding the expansion of Austrocedrus by
    1000-1500 yr. The spread of Austrocedrus is explained by a shift
    towards a cooler and wetter climate in the middle and late Holocene.
    The change to a surface-fire regime is consistent with increased
    interannual climate variability and the onset or strengthening of
    ENSO. The present-day mixed forest dominated by Nothofagus and Austrocedrus
    was established in the last few millennia. (c) 2006 University of
    Washington. All rights reserved.
    BibTeX:
    @article{Whitlock2006,
      author = {Whitlock, C and Bianchi, MM and Bartlein, PJ and Markgraf, V and Marlon, J and Walsh, M and McCoy, N},
      title = {Postglacial vegetation, climate, and fire history along the east side of the Andes (lat 41-42.5 degrees S), Argentina},
      journal = {Quaternary Research},
      year = {2006},
      volume = {66},
      number = {2},
      pages = {187--201}
    }
    					
    Briles2005 Briles, C.E.; Whitlock, C. & Bartlein, P.J. Postglacial vegetation, fire, and climate history of the Siskiyou Mountains, Oregon, USA 2005 Quaternary Research
    Vol. 64 (1) , pp. 44-56  
    article fire: modern and paleo
    Abstract: The forests of the Siskiyou Mountains are among the most diverse in
    North America, yet the long-term relationship among climate, diversity,
    and natural disturbance is not well known. Pollen, plant macrofossils,
    and high-resolution charcoal data from Bolan Lake, Oregon, were analyzed
    to reconstruct a 17,000-yr-long environmental history of high-elevation
    forests in the region. In the late-glacial period, the presence of
    a subalpine parkland of Artemisia, Poaceae, Pinus, and Tsuga with
    infrequent fires suggests cool dry conditions. After 14,500 cal yr
    B.P., a closed forest of Abies, Pseudotsuga, Tsuga, and Alnus rubra
    with more frequent fires developed which indicates more mesic conditions
    than before. An open woodland of Pinus, Quercus, and Cupressaceae,
    with higher fire activity than before, characterized the early Holocene
    and implies warmer and drier conditions than at present. In the late
    Holocene, Abies and Picea were more prevalent in the forest, suggesting
    a return to cool wet conditions, although fire-episode frequency
    remained relatively high. The modem forest of Abies and Pseudotsuga
    and the present-day fire regime developed ca. 2100 cal yr B.P. and
    indicates that conditions had become slightly drier than before.
    Sub-millennial-scale fluctuations in vegetation and fire activity
    suggest climatic variations during the Younger Dryas interval and
    within the early Holocene period. The timing of vegetation changes
    in the Bolan Lake record is similar to that of other sites in the
    Pacific Northwest and Klamath region, and indicates that local vegetation
    communities were responding to regional-scale climate changes. The
    record implies that climate-driven millennial- to centennial-scale
    vegetation and fire change should be considered when explaining the
    high floristic diversity observed at present in the Siskiyou Mountains.
    (c) 2005 University of Washington. All rights reserved.
    BibTeX:
    @article{Briles2005,
      author = {Briles, CE and Whitlock, C and Bartlein, PJ},
      title = {Postglacial vegetation, fire, and climate history of the Siskiyou Mountains, Oregon, USA},
      journal = {Quaternary Research},
      year = {2005},
      volume = {64},
      number = {1},
      pages = {44--56}
    }
    					
    Brunelle2005 Brunelle, A.; Whitlock, C.; Bartlein, P. & Kipfmueller, K. Holocene fire and vegetation along environmental gradients in the Northern Rocky Mountains 2005 Quaternary Science Reviews
    Vol. 24 (20-21) , pp. 2281-2300  
    article fire: modern and paleo
    Abstract: Holocene records of fire, vegetation, and climate were reconstructed
    from four sites in the Bitterroot Range region of the Northern Rocky
    Mountains in order to examine the vegetation and fire histories and
    evaluate the hypothesis proposed by Whitlock and Bartlein (1993)
    regarding the effects of increased summer insolation on precipitation
    patterns. Vegetation history in the series of sites was broadly similar.
    In the late-glacial period, the pollen data suggest open parkland
    dominated by Picea or alpine meadow, which reflect conditions cooler
    and drier than present. These open forests were replaced in the early
    to middle Holocene by forests composed mainly of Pinus and Pseudotsuga,
    which suggest conditions warmer than present. Modern forest compositions
    were in place by ca 3000 cal yr BP, and small variations in the timing
    of the vegetation shifts reflect local differences among sites. The
    long-term trends in fire occurrence support the hypothesis proposed
    by Whitlock and Bartlein (1993) that precipitation regimes were sharpened
    during the early Holocene summer insolation maximum but their location
    has remained unchanged as a result of topographic constraints. Sites
    located in areas currently summer-dry were drier-than-present during
    the early Holocene and fires were more frequent. Conversely, sites
    located in the areas that are summer-wet at present were wetter-than-present
    in the early Holocene, and fires were less frequent. On millennial
    time scales it appears that the climate boundary is controlled by
    topography and does not shift. (c) 2005 Elsevier Ltd. All rights
    reserved.
    BibTeX:
    @article{Brunelle2005,
      author = {Brunelle, A and Whitlock, C and Bartlein, P and Kipfmueller, K},
      title = {Holocene fire and vegetation along environmental gradients in the Northern Rocky Mountains},
      journal = {Quaternary Science Reviews},
      year = {2005},
      volume = {24},
      number = {20-21},
      pages = {2281--2300}
    }
    					
    Clegg2005 Clegg, B.F.; Tinner, W.; Gavin, D.G. & Hu, F.S. Morphological differentiation of Betula (birch) pollen in northwest North America and its palaeoecological application 2005 Holocene
    Vol. 15 (2) , pp. 229-237  
    article
    Abstract: Lake sediments from arcto-boreal regions commonly contain abundant
    Betula pollen. However, palaeoenvironmental interpretations of Betula
    pollen are often ambiguous because of the lack of reliable morphological
    features to distinguish among ecologically distinct Betula species
    in western North America. We measured the grain diameters and pore
    depths of pollen from three tree-birch species (B. papyrifera, B.
    kenaica and B. neoalaskana) and two shrub-birch species (B. glandulosa
    and B. nana), and calculated the ratio of grain diameter to pore
    depth (D/P ratio). No statistical difference exists in all three
    parameters between the shrub-birch species or between two of the
    tree-birch species (B. kenaica and B. papyrifera), and B. neoalaskana
    is intermediate between the shrub-birch and the other two tree-birch
    species. However, mean pore depth is significantly larger for the
    tree species than for the shrub species. In contrast, mean grain
    diameter cannot distinguish tree and shrub species. Mean D/P ratio
    separates tree and shrub species less clearly than pore depth, but
    this ratio can be used for verification. The threshold for distinguishing
    pollen of tree versus shrub birch lies at 2.55 mm and 8.30 for pore
    depth and D/P ratio, respectively. We applied these thresholds to
    the analysis of Betula pollen in an Alaskan lake-sediment core spanning
    the past 800 years. Results show that shrub birch increased markedly
    at the expense of tree birch during the 'Little Ice Age'; this pattern
    is not discernible in the profile of total birch pollen.
    BibTeX:
    @article{Clegg2005,
      author = {Clegg, BF and Tinner, W and Gavin, DG and Hu, FS},
      title = {Morphological differentiation of Betula (birch) pollen in northwest North America and its palaeoecological application},
      journal = {Holocene},
      year = {2005},
      volume = {15},
      number = {2},
      pages = {229--237}
    }
    					
    Conyers2005 Conyers, M.M. & Fonstad, M.A. The unusual channel resistance of the Texas Hill Country and its effect on flood flow predictions 2005 Physical Geography
    Vol. 26 (5) , pp. 379-395  
    article mannings-n, streams
    Abstract: The importance of hydraulic roughness estimates in modeling river
    flow cannot be overstated. Spatial and temporal variation of flow
    resistance can have a dramatic effect on the prediction of floodplain
    width, depth, and other hydraulic properties. The Texas Hill Country,
    a physiographic region of uplifted and differentially eroded limestone
    in south-central Texas, is the site of considerably heterogeneous
    fluvial forms and processes. Predictions of the spatial extent of
    floods in this area are difficult given this topographic and fluvial
    heterogeneity. In this report, we present a new method to extract
    spatial maps of hydraulic roughness using channel geometry and newly
    accessible USGS National Water Information System (NWIS) data.
    We use these data to construct maps of hydraulic roughness at different
    discharges and to test roughness prediction methods suggested by
    previous authors. Our method for extracting roughness values is general
    and should be applicable in most areas of the United States. The
    patterns of hydraulic resistance around the Texas Hill Country and
    through its eastern boundary, the Balcones Escarpment, are spatially
    diverse, ranging from n congruent to 0.016 to 0.213, and no simple
    spatial pattern of roughness exists. The most unexpected finding
    is the high values of Manning's roughness value (n) in most areas
    of the Hill Country, with n values often two or three times greater
    (n congruent to 0.04-0.06) than what would be expected using common
    n-estimation techniques (n congruent to 0.01-0.02). This simple finding
    is of practical importance because the too-low values of Manning's
    roughness are almost certainly translated into floodplain maps as
    too narrowly delineated floodplains.
    BibTeX:
    @article{Conyers2005,
      author = {Conyers, M. M. and Fonstad, M. A.},
      title = {The unusual channel resistance of the Texas Hill Country and its effect on flood flow predictions},
      journal = {Physical Geography},
      year = {2005},
      volume = {26},
      number = {5},
      pages = {379--395},
      doi = {http://doi.org/10.2747/0272-3646.26.5.379}
    }
    					
    Fonstad2005 Fonstad, M.A. & Marcus, W.A. Remote sensing of stream depths with hydraulically assisted bathymetry (HAB) models 2005 Geomorphology
    Vol. 72 (1-4) , pp. 320-339  
    article remote sensing fluvial geomorphology
    Abstract: This article introduces a technique for using a combination of remote
    sensing imagery and open-channel flow principles to estimate depths
    for each pixel in an imaged river. This technique, which we term
    hydraulically assisted bathymetry (HAB), uses a combination of local
    stream gage information on discharge, image brightness data, and
    Manning-based estimates of stream resistance to calculate water depth.
    The HAB technique does not require ground-truth depth information
    at the time of flight. HAB can be accomplished with multispectral
    or hyperspectral data, and therefore can be applied over entire watersheds
    using standard high spatial resolution satellite or aerial images.
    HAB also has the potential to be applied retroactively to historic
    imagery, allowing researchers to map temporal changes in depth. We
    present two versions of the technique, HAB-1 and HAB-2. HAB-1 is
    based primarily on the geometry, discharge and velocity relationships
    of river channels. Manning's equation (assuming average depth approximates
    the hydraulic radius), the discharge equation, and the assumption
    that the frequency distribution of depths within a cross-section
    approximates that of a triangle are combined with discharge data
    from a local station, width measurements from imagery, and slope
    measurements from maps to estimate minimum, average and maximum depths
    at a multiple cross-sections. These depths are assigned to pixels
    of maximum, average, and minimum brightness within the cross-sections
    to develop a brightness-depth relation to estimate depths throughout
    the remainder of the river. HAB-2 is similar to HAB-1 in operation,
    but the assumption that the distribution of depths approximates that
    of a triangle is replaced by an optical Beer-Lambert law of light
    absorbance. In this case, the flow equations and the optical equations
    are used to iteratively scale the river pixel values until their
    depths produce a discharge that matches that of a nearby gage. R-2
    values for measured depths versus depths estimated by FLAB-I and
    HAB-2 are 0.51 and 0.77, respectively, in the relatively simple Brazos
    River, Texas R-2 values for HAB-1 and HAB-2 are 0.46 and 0.26, respectively,
    in the Lamar River, a complex mountain river system in Yellowstone
    National Park. Although the R-2 values are moderate, depth maps and
    cross-sections derived from the HAB techniques are consistent with
    typical stream geomorphology patterns and provide far greater spatial
    coverage and detail than could be achieved with ground-based survey
    techniques. Improved depth estimates can be achieved by stratifying
    the river into different habitat types that normalize for differences
    in turbulence and substrate. (c) 2005 Elsevier B.V. All rights reserved.
    BibTeX:
    @article{Fonstad2005,
      author = {Fonstad, MA and Marcus, WA},
      title = {Remote sensing of stream depths with hydraulically assisted bathymetry (HAB) models},
      journal = {Geomorphology},
      year = {2005},
      volume = {72},
      number = {1-4},
      pages = {320--339}
    }
    					
    Gavin2005 Gavin, D.G. & Hu, F.S. Bioclimatic modelling using Gaussian mixture distributions and multiscale segmentation 2005 Global Ecology and Biogeography
    Vol. 14 (5) , pp. 491-501  
    article
    Abstract: Aim To introduce Gaussian mixture distributions and sequential maximum
    a posteriori image segmentation (GM-SMAP) as a model that predicts
    species ranges from mapped climatic variables, and to compare its
    predictive capacity with two commonly used bioclimatic models: regression
    tree analysis (RTA) and smoothed response surfaces (SRS). Location
    North-west North America. Methods We compared models for their ability
    to predict the distributional range of western hemlock (Tsuga heterophylla).
    We calculated and projected nine climatic and water-balance variables
    to a 2-km grid up to 140 km from the T. heterophylla range. Models
    were trained using the five variables selected by RTA, as well as
    subsets of three variables. Goodness of fit was assessed using models
    trained and tested on the entire study area. Predictive capacity
    was assessed using 100 cross-validation tests, each trained on a
    randomly sampled 1% of the study area and tested on the complement
    of the study area. Results Models using all five variables were significantly
    better than three-variable models. Model fit was greatest for SRS.
    GM-SMAP misclassified slightly more area and RTA misclassified almost
    twice the area compared to SRS. However, cross- validation showed
    that the predictive capacity was clearly greatest for GM-SMAP and
    lowest for SRS, indicating that GM-SMAP makes more accurate predictions
    from sparse data. Main conclusions GM distributions prevent overfitting
    using an information-theoretic approach, and the SMAP algorithm minimizes
    the spatial extent of the largest misclassified area using a multiscale
    method. These properties, useful for image classification, also aid
    their strong predictive capacity as a bioclimatic model. SRS overfit
    the data, lowering its predictive capacity, and RTA failed to capture
    details of interactions among variables, yielding a poor fit. These
    results demonstrate the strong potential of GM-SMAP as a bioclimatic
    model.
    BibTeX:
    @article{Gavin2005,
      author = {Gavin, DG and Hu, FS},
      title = {Bioclimatic modelling using Gaussian mixture distributions and multiscale segmentation},
      journal = {Global Ecology and Biogeography},
      year = {2005},
      volume = {14},
      number = {5},
      pages = {491--501}
    }
    					
    Gavin2005a Gavin, D.G.; Brubaker, L.B.; McLachlan, J.S. & Oswald, W.W. Correspondence of pollen assemblages with forest zones across steep environmental gradients, Olympic Peninsula, Washington, USA 2005 Holocene
    Vol. 15 (5) , pp. 648-662  
    article vegetation and climate
    Abstract: The use of pollen records to document vegetation responses to climatic
    change in mountains relies on the ability of pollen assemblages to
    differentiate among elevationally stratified vegetation zones. Comparisons
    among modern pollen assemblages within mountainous areas provide
    a basis for assessing this potential. We examined relationships between
    pollen assemblages, forest vegetation and climate at 65 small lake
    sites distributed across five forest zones on the Olympic Peninsula,
    Washington. Sample sites spanned nearly the full range of climatic
    gradients on the Peninsula, e. 900-6000 mm annual precipitation and
    c. 17-8 degrees C July mean temperature (from 9 to 1981 m a.s.l.).
    The pollen percentages of most arboreal taxa showed a strong relationship
    with elevation, especially for taxa with poor dispersal potential
    (Abies and Picea) or high elevation ranges (Tsuga mertensiana and
    Alnus sinuata). Tsuga heterophylla was the only pollen taxon abundant
    across all forest zones. Both detrended correspondence analysis (DCA)
    and linear discriminant analysis (DA) arranged pollen assemblages
    along temperature and precipitation gradients approximating the actual
    distribution of vegetation along these gradients. DA classified 90%,
    of the sites into their correct forest zones, but was very sensitive
    to sample size, suggesting that caution should be exercised when
    using DA for classifying fossil pollen assemblages. Pairwise comparisons
    using the squared-chord-distance metric (SCD) showed that the SCD
    threshold that best distinguishes neighbouring forest zones is affected
    by the number of samples in each forest zone and by the patchiness
    of species distributions within each zone, suggesting that SCD is
    also sensitive to sample size and that thresholds used with the modern
    analogue technique must be calibrated for each vegetation zone. This
    study indicates that pollen assemblages on the Olympic Peninsula
    record local forest zones despite steep environmental gradients and
    the close proximity of neighbouring forest zones.
    BibTeX:
    @article{Gavin2005a,
      author = {Gavin, DG and Brubaker, LB and McLachlan, JS and Oswald, WW},
      title = {Correspondence of pollen assemblages with forest zones across steep environmental gradients, Olympic Peninsula, Washington, USA},
      journal = {Holocene},
      year = {2005},
      volume = {15},
      number = {5},
      pages = {648--662}
    }
    					
    Goovaerts2005 Goovaerts, P.; Jacquez, G.M. & Marcus, W.A. Geostatistical and local cluster analysis of high resolution hyperspectral imagery for detection of anomalies 2005 Remote Sensing of Environment
    Vol. 95 , pp. 351-367  
    article remote sensing
    BibTeX:
    @article{Goovaerts2005,
      author = {Goovaerts, P and Jacquez, GM and Marcus, WA},
      title = {Geostatistical and local cluster analysis of high resolution hyperspectral imagery for detection of anomalies},
      journal = {Remote Sensing of Environment},
      year = {2005},
      volume = {95},
      pages = {351-367}
    }
    					
    Shafer2005 Shafer, S.L.; Bartlein, P.J. & Whitlock, C. Huber, U.; Reasoner, M. & Bugmann, H. (Hrsg.) Understanding the spatial heterogeneity of global environmental change in mountain regions ( Global Change and Mountain Regions ) 2005 Global Change and Mountain Regions   inbook future vegetation changes
    BibTeX:
    @inbook{Shafer2005,
      author = {Shafer, SL and Bartlein, PJ and Whitlock, C},
      title = {Global Change and Mountain Regions},
      publisher = {Springer, Heidelburg},
      year = {2005}
    }
    					
    Shuman2005 Shuman, B.; Bartlein, P.J. & Webb, T. The magnitudes of millennial- and orbital-scale climatic change in eastern North America during the Late Quaternary 2005 Quaternary Science Reviews
    Vol. 24 (20-21) , pp. 2194-2206  
    article paleoclimatic analysis and data-model comparisons
    Abstract: Temporal differences among fossil pollen samples from eastern North
    America provide a measure of the amount of climatic change that occurred
    on a broad spatial scale since the last glacial maximum (21,000 cal
    yr BP). Square-chord distances (SCDs) quantify the difference between
    pollen samples, and, thus, represent the potential magnitude of climatic
    change underlying the pollen record. The magnitude varied significantly
    among time scales with small changes common at centennial to millennial
    scales and large changes common at multi-millennial (i.e. orbital)
    scales. SCDs measured across 3000-yr intervals averaged 0.20, and
    often exceeded the maximum difference expected from samples collected
    within the same biome (0.15). SCDs across individual millennia were
    smaller and averaged 0.08. SCDs across the millennia at the beginning
    (13,000-12,000cal yr BP) and end (12,000-11,000 cat yr BP) of the
    Younger Dryas chronozone (12,900-11,600 cal yr BP), however, averaged
    0.20 and 0.18, respectively. These rapid step changes, large at sub-millennial
    scales, equal about 5-25% of the total glacial-interglacial transition.
    Large magnitude progressive changes in insolation, ice sheet extent,
    and atmospheric composition parallel the dominant trends in the SCD
    data, which show that progressive change comprises the first-order
    climatic pattern of the Holocene rather than stable or oscillatory
    patterns. (c) 2005 Elsevier Ltd. All rights reserved.
    BibTeX:
    @article{Shuman2005,
      author = {Shuman, B and Bartlein, PJ and Webb, T},
      title = {The magnitudes of millennial- and orbital-scale climatic change in eastern North America during the Late Quaternary},
      journal = {Quaternary Science Reviews},
      year = {2005},
      volume = {24},
      number = {20-21},
      pages = {2194--2206}
    }
    					
    Whitmore2005 Whitmore, J.; Gajewski, K.; Sawada, M.; Williams, J.W.; Shuman, B.; Bartlein, P.J.; Minckley, T.; Viau, A.E.; Webb, T.; Shafer, S.; Anderson, P. & Brubaker, L. Modern pollen data from North American and Greenland for multi-scale paleoenvironmental applications 2005 Quaternary Science Reviews
    Vol. 24 (16-17) , pp. 1828-1848  
    article vegetation and climate
    Abstract: The modern pollen network in North America and Greenland is presented
    as a database for use in quantitative calibration studies and paleoenvironmental
    reconstructions. The georeferenced database includes 4634 samples
    from all regions of the continent and 134 pollen taxa that range
    from ubiquitous to regionally diagnostic taxa. Climate data and vegetation
    characteristics were assigned to every site. Automated and manual
    procedures were used to verify the accuracy of geographic coordinates
    and identify duplicate records among datasets, incomplete pollen
    sums, and other potential errors. Data are currently available for
    almost all of North America, with variable density. Pollen taxonomic
    diversity, as measured by the Shannon-Weiner coefficient, varies
    as a function of location, as some vegetation regions are dominated
    by one or two major pollen producers, while other regions have a
    more even composition of pollen taxa. Squared-chord distances computed
    between samples show that most modern pollen samples find analogues
    within their own vegetation zone. Both temperature and precipitation
    inferred from best analogues are highly correlated with observed
    values but temperature exhibits the strongest relation. Maps of the
    contemporary distribution of several pollen types in relation to
    the range of the plant taxon illustrate the correspondence between
    plant and pollen ranges. (c) 2005 Elsevier Ltd. All rights reserved.
    BibTeX:
    @article{Whitmore2005,
      author = {Whitmore, J and Gajewski, K and Sawada, M and Williams, JW and Shuman, B and Bartlein, PJ and Minckley, T and Viau, AE and Webb, T and Shafer, S and Anderson, P and Brubaker, L},
      title = {Modern pollen data from North American and Greenland for multi-scale paleoenvironmental applications},
      journal = {Quaternary Science Reviews},
      year = {2005},
      volume = {24},
      number = {16-17},
      pages = {1828--1848}
    }
    					
    Barboni2004 Barboni, D.; Harrison, S.P.; Bartlein, P.J.; Jalut, G.; New, M.; Prentice, I.C.; Sanchez-Goni, M.F.; Spessa, A.; Davis, B. & Stevenson, A.C. Relationships between plant traits and climate in the Mediterranean region: A pollen data analysis 2004 Journal of Vegetation Science
    Vol. 15 (5) , pp. 635-646  
    article vegetation and climate
    Abstract: Question: What are the correlations between the degree of drought
    stress and temperature, and the adoption of specific adaptive strategies
    by plants in the Mediterranean region? Location: 602 sites across
    the Mediterranean region. Method: We considered 12 plant morphological
    and phenological traits, and measured their abundance at the sites
    as trait scores obtained from pollen percentages. We conducted stepwise
    regression analyses of trait scores as a function of plant available
    moisture (alpha) and winter temperature (MTCO). Results: Patterns
    in the abundance for the plant traits we considered are clearly determined
    by alpha, MTCO or a combination of both. In addition, trends in leaf
    size, texture, thickness, pubescence and aromatic leaves and other
    plant level traits such as thorniness and aphylly, vary according
    to the life form (tree, shrub, forb), the leaf type (broad, needle)
    and phenology (evergreen, summer-green). Conclusions: Despite conducting
    this study based on pollen data we have identified ecologically plausible
    trends in the abundance of traits along climatic gradients. Plant
    traits other than the usual life form, leaf type and leaf phenology
    carry strong climatic signals. Generally, combinations of plant traits
    are more climatically diagnostic than individual traits. The qualitative
    and quantitative relationships between plant traits and climate parameters
    established here will help to provide an improved basis for modelling
    the impact of climate changes on vegetation and form a starting point
    for a global analysis of pollen-climate relationships.
    BibTeX:
    @article{Barboni2004,
      author = {Barboni, D and Harrison, SP and Bartlein, PJ and Jalut, G and New, M and Prentice, IC and Sanchez-Goni, MF and Spessa, A and Davis, B and Stevenson, AC},
      title = {Relationships between plant traits and climate in the Mediterranean region: A pollen data analysis},
      journal = {Journal of Vegetation Science},
      year = {2004},
      volume = {15},
      number = {5},
      pages = {635--646}
    }
    					
    Bartlein2004 Bartlein, P.J. & Hostetler, S.W. Gillespie, A.R.; Porter, S.C. & Atwater, B.F. (Hrsg.) Modeling paleoclimates ( The Quaternary Period in the United States ) 2004 The Quaternary Period in the United States , pp. 563-582   inbook
    BibTeX:
    @inbook{Bartlein2004,
      author = {Bartlein, PJ and Hostetler, SW},
      title = {The Quaternary Period in the United States},
      publisher = {Elsevier, Amsterdam},
      year = {2004},
      pages = {563-582}
    }
    					
    Bonfils2004 Bonfils, C.; de Noblet-Ducoudre, N.; Guiot, J. & Bartlein, P. Some mechanisms of mid-Holocene climate change in Europe, inferred from comparing PMIP models to data 2004 Climate Dynamics
    Vol. 23 (1) , pp. 79-98  
    article paleoclimatic analysis and data-model comparisons
    Abstract: We propose a new approach for comparing mid-Holocene climates from
    18 PMIP simulations with climate reconstructions of winter and growing
    season temperatures and the annual water budget inferred from European
    pollen and lake-level data. A cluster analysis is used to extract
    patterns of multivariate climate response from the reconstructions;
    these are then compared to the patterns simulated by models. According
    to paleodata, summers during mid-Holocene were warmer-than-present
    in the north, and cooler-than-present in the south, while winters
    were colder-than-present in the southwest but milder-than-present
    in the northeast. Whereas warmer summers and colder winters may easily
    be explained as a direct response to the amplified seasonal cycle
    of insolation during the mid-Holocene, the other recorded responses
    are less straightforward to explain. We have identified, from the
    models that correctly simulate the recorded climate change, two important
    atmospheric and hydrological processes that can compensate for direct
    insolation effects. First, a stronger-than-present airflow from southwestern
    Europe that veers to the north over Eastern Europe, in winter, can
    consistently explain the reconstructed changes in this season's temperatures
    and water budget. Second, the increased winter soil moisture allows
    a shift of the partitioning of net radiative energy towards latent
    rather than sensible heat fluxes, thereby decreasing surface temperature
    during the following summer season. Our approach therefore solves
    one of the recurring problems in model-data comparisons that arises
    when a model simulates the correct response but in the wrong location
    (as a consequence, for instance, of model resolution and topography).
    BibTeX:
    @article{Bonfils2004,
      author = {Bonfils, C and de Noblet-Ducoudre, N and Guiot, J and Bartlein, P},
      title = {Some mechanisms of mid-Holocene climate change in Europe, inferred from comparing PMIP models to data},
      journal = {Climate Dynamics},
      year = {2004},
      volume = {23},
      number = {1},
      pages = {79--98}
    }
    					
    Foit2004 Foit, F.F.; Gavin, D.G. & Hu, F.S. The tephra stratigraphy of two lakes in south-central British Columbia, Canada and its implications for mid-late Holocene volcanic activity at Glacier Peak and Mount St. Helens, Washington, USA 2004 Canadian Journal of Earth Sciences
    Vol. 41 (12) , pp. 1401-1410  
    article
    Abstract: Several mid-late Holocene Glacier Peak tephras along with Mazama and
    Mount St. Helens Wn and P tephras were found in cores from Cooley
    and Rockslide lakes in southeastern British Columbia, similar to300
    km northeast of Glacier Peak. The sediments in Cooley Lake host the
    late Holocene Glacier Peak A tephra (2010 calibrated (cal) years
    BP), four separate Glacier Peak Dusty Creek (GPDC) tephras (5780-5830
    cal years BP), and a Glacier Peak set D tephra (6060 cal years BP).
    This is the first report of Glacier Peak A and D tephras in British
    Columbia. The A tephra has been correlated on the basis of glass
    composition and age to a late Holocene Glacier Peak tephra in the
    sediments of Big Twin Lake, 75 km northeast of Glacier Peak. The
    glasses in the four GPDC tephra layers from Cooley Lake are compositionally
    indistinguishable from those in Mount Barr Cirque and Frozen lakes
    in southwestern British Columbia. The layers likely represent four
    eruptions taking place over 50 years. Although set D tephra has not
    been correlated to a known proximal or distal deposit, its glass
    bears the Glacier Peak glass compositional signature and its interpolated
    age corresponds to the initiation of the set D eruptive period. The
    presence of GPDC tephra in lake sediments across southern British
    Columbia suggests a broad plume trajectory to the north and northeast,
    whereas the apparent absence of the A and D tephras in all but Cooley
    Lake suggest plumes with a northeasterly direction.
    BibTeX:
    @article{Foit2004,
      author = {Foit, FF and Gavin, DG and Hu, FS},
      title = {The tephra stratigraphy of two lakes in south-central British Columbia, Canada and its implications for mid-late Holocene volcanic activity at Glacier Peak and Mount St. Helens, Washington, USA},
      journal = {Canadian Journal of Earth Sciences},
      year = {2004},
      volume = {41},
      number = {12},
      pages = {1401--1410}
    }
    					
    Huntley2004 Huntley, B.; Green, R.E.; Collingham, Y.C.; Hill, J.K.; Willis, S.G.; Bartlein, P.J.; Cramer, W.; Hagemeijer, W.J.M. & Thomas, C.J. The performance of models relating species geographical distributions to climate is independent of trophic level 2004 Ecology Letters
    Vol. 7 (5) , pp. 417-426  
    article vegetation and climate
    Abstract: Species - climate 'envelope' models are widely used to evaluate potential
    climate change impacts upon species and biodiversity. Previous studies
    have used a variety of methods to fit models making it difficult
    to assess relative model performance for different taxonomic groups,
    life forms or trophic levels. Here we use the same climatic data
    and modelling approach for 306 European species representing three
    major taxa ( higher plants, insects and birds), and including species
    of different life form and from four trophic levels. Goodness-of-fit
    measures showed that useful models were fitted for > 96% of species,
    and that model performance was related neither to major taxonomic
    group nor to trophic level. These results confirm that such climate
    envelope models provide the best approach currently available for
    evaluating reliably the potential impacts of future climate change
    upon biodiversity.
    BibTeX:
    @article{Huntley2004,
      author = {Huntley, B and Green, RE and Collingham, YC and Hill, JK and Willis, SG and Bartlein, PJ and Cramer, W and Hagemeijer, WJM and Thomas, CJ},
      title = {The performance of models relating species geographical distributions to climate is independent of trophic level},
      journal = {Ecology Letters},
      year = {2004},
      volume = {7},
      number = {5},
      pages = {417--426}
    }
    					
    Kaufman2004 Kaufman, D.S.; Ager, T.A.; Anderson, N.J.; Anderson, P.M.; Andrews, J.T.; Bartlein, P.J.; Brubaker, L.B.; Coats, L.L.; Cwynar, L.C.; Duvall, M.L.; Dyke, A.S.; Edwards, M.E.; Eisner, W.R.; Gajewski, K.; Geirsdottir, A.; Hu, F.S.; Jennings, A.E.; Kaplan, M.R.; Kerwin, M.N.; Lozhkin, A.V.; MacDonald, G.M.; Miller, G.H.; Mock, C.J.; Oswald, W.W.; Otto-Bliesner, B.L.; Porinchu, D.F.; Ruhland, K.; Smol, J.P.; Steig, E.J. & Wolfe, B.B. Holocene thermal maximum in the western Arctic (0-180 degrees W) 2004 Quaternary Science Reviews
    Vol. 23 (5-6) , pp. 529-560  
    article
    Abstract: The spatio-temporal pattern of peak Holocene warmth (Holocene thermal
    maximum, HTM) is traced over 140 sites across the Western Hemisphere
    of the Arctic (0-180degreesW; north of similar to60degreesN). Paleoclimate
    inferences based on a wide variety of proxy indicators provide clear
    evidence for warmer-than-present conditions at 120 of these sites.
    At the 16 terrestrial sites where quantitative estimates have been
    obtained, local HTM temperatures (primarily summer estimates) were
    on average 1.6+/-0.8degreesC higher than present (approximate average
    of the 20th century), but the warming was time-transgressive across
    the western Arctic. As the precession-driven summer insolation anomaly
    peaked 12-10ka (thousands of calendar years ago), warming was concentrated
    in northwest North America, while cool conditions lingered in the
    northeast. Alaska and northwest Canada experienced the HTM between
    ca 11 and 9 ka, about 4000 yr prior to the HTM in northeast Canada.
    The delayed warming in Quebec and Labrador was linked to the residual
    Laurentide Ice Sheet, which chilled the region through its impact
    on surface energy balance and ocean circulation. The lingering ice
    also attests to the inherent asymmetry of atmospheric and oceanic
    circulation that predisposes the region to glaciation and modulates
    the pattern of climatic change. The spatial asymmetry of warming
    during the HTM resembles the pattern of warming observed in the Arctic
    over the last several decades. Although the two warmings are described
    at different temporal scales, and the HTM was additionally affected
    by the residual Laurentide ice, the similarities suggest there might
    be a preferred mode of variability in the atmospheric circulation
    that generates a recurrent pattern of warming under positive radiative
    forcing. Unlike the HTM, however, future warming will not be counterbalanced
    by the cooling effect of a residual North American ice sheet. (C)
    2003 Elsevier Ltd. All rights reserved.
    BibTeX:
    @article{Kaufman2004,
      author = {Kaufman, DS and Ager, TA and Anderson, NJ and Anderson, PM and Andrews, JT and Bartlein, PJ and Brubaker, LB and Coats, LL and Cwynar, LC and Duvall, ML and Dyke, AS and Edwards, ME and Eisner, WR and Gajewski, K and Geirsdottir, A and Hu, FS and Jennings, AE and Kaplan, MR and Kerwin, MN and Lozhkin, AV and MacDonald, GM and Miller, GH and Mock, CJ and Oswald, WW and Otto-Bliesner, BL and Porinchu, DF and Ruhland, K and Smol, JP and Steig, EJ and Wolfe, BB},
      title = {Holocene thermal maximum in the western Arctic (0-180 degrees W)},
      journal = {Quaternary Science Reviews},
      year = {2004},
      volume = {23},
      number = {5-6},
      pages = {529--560}
    }
    					
    Legleiter2004 Legleiter, C.J.; Roberts, D.A.; Marcus, W.A. & Fonstad, M.A. Passive optical remote sensing of river channel morphology and in-stream habitat: Physical basis and feasibility 2004 Remote Sensing of Environment
    Vol. 93 (4) , pp. 493-510  
    article
    Abstract: Successful monitoring of ecologically significant, vulnerable fluvial
    systems will require improved quantitative techniques for mapping
    channel morphology and in-stream habitat. In this study, we assess
    the ability of remote sensing to contribute to these objectives by
    (1) describing the underlying radiative transfer processes, drawing
    upon research conducted in shallow marine environments; (2) modeling
    the effects of water depth, substrate type, suspended sediment concentration,
    and surface turbulence; (3) quantifying the limitations imposed by
    finite detector sensitivity and linear quantization; and (4) evaluating
    two depth retrieval algorithms using simulated and field-measured
    spectra and archival imagery. The degree to which variations in depth
    and substrate can be resolved depends on bottom albedo and water
    column optical properties, and scattering by suspended sediment obscures
    substrate spectral features and reduces the resolution of depth estimates.
    Converting continuous radiance signals to discrete digital numbers
    implies that depth estimates take the form of contour intervals that
    become wider as depth increases and as bottom albedo and detector
    sensitivity decrease. Our results indicate that a simple band ratio
    can provide an image-derived variable that is strongly linearly related
    to water depth across a broad range of stream conditions. This technique
    outperformed the linear transform method used in previous stream
    studies, most notably for upwelling radiance spectra [R-2=0.79 for
    the ln(560 nm/690 nm) ratio]. Applied to uncalibrated multispectral
    and hyperspectral images of a fourth-order stream in Yellowstone
    National Park, this flexible technique produced hydraulically reasonable
    maps of relative depth. Although radiometric precision and spatial
    resolution will impose fundamental limitations in practice, remote
    mapping of channel morphology and in-stream habitat is feasible and
    can become a powerful tool for scientists and managers. (C) 2004
    Elsevier Inc. All rights reserved.
    BibTeX:
    @article{Legleiter2004,
      author = {Legleiter, CJ and Roberts, DA and Marcus, WA and Fonstad, MA},
      title = {Passive optical remote sensing of river channel morphology and in-stream habitat: Physical basis and feasibility},
      journal = {Remote Sensing of Environment},
      year = {2004},
      volume = {93},
      number = {4},
      pages = {493--510}
    }
    					
    Light2004 Light, A. & Bartlein, P.J. The end of the rainbow? Color schemes for improved data graphics 2004 Eos
    Vol. 85 , pp. 385,391  
    article scientific visualization
    BibTeX:
    @article{Light2004,
      author = {Light, A and Bartlein, PJ},
      title = {The end of the rainbow? Color schemes for improved data graphics},
      journal = {Eos},
      year = {2004},
      volume = {85},
      pages = {385,391}
    }
    					
    Millspaugh2004 Millspaugh, S.H.; Whitlock, C. & Bartlein, P.J. Wallace, L.L. (Hrsg.) Postglacial fire, vegetation, and climate history of the Yellowstone-Lamar and Central Plateau Provinces, Yellowstone National Park ( After the Fires, The Ecology of Change in Yellowstone National Park ) 2004 After the Fires, The Ecology of Change in Yellowstone National Park
    Vol. l , pp. 10-28  
    inbook fire: modern and paleo
    BibTeX:
    @inbook{Millspaugh2004,
      author = {Millspaugh, SH and Whitlock C and Bartlein PJ},
      title = {After the Fires, The Ecology of Change in Yellowstone National Park},
      publisher = {Yale University Press, New Haven},
      year = {2004},
      volume = {l},
      pages = {10-28}
    }
    					
    Thompson2004 Thompson, R.S.; Shafer, S.L.; Anderson, K.H.; Strickland, L.E.; Pelltier, R.T.; Bartlein, P.J. & Kerwin, M.W. Topographic, bioclimatic, and vegetation characteristics of three ecoregion classification systems in North America: Comparisons along continent-wide transects 2004 Environmental Management
    Vol. 34 , pp. S125-S148-S125-S148  
    article vegetation and climate
    Abstract: Ecoregion classification systems are increasingly used for policy
    and management decisions, particularly among conservation and natural
    resource managers. A number of ecoregion classification systems are
    currently available, with each system defining ecoregions using different
    classification methods and different types of data. As a result,
    each classification system describes a unique set of ecoregions.
    To help potential users choose the most appropriate ecoregion system
    for their particular application, we used three latitudinal transects
    across North America to compare the boundaries and environmental
    characteristics of three ecoregion classification systems [Kuchler,
    World Wildlife Fund (WWF), and Bailey]. A variety of variables were
    used to evaluate the three systems, including woody plant species
    richness, normalized difference in vegetation index (NDVI), and bioclimatic
    variables (e.g., mean temperature of the coldest month) along each
    transect. Our results are dominated by geographic patterns in temperature,
    which are generally aligned north-south, and in moisture, which are
    generally aligned east-west. In the west, the dramatic changes in
    physiography, climate, and vegetation impose stronger controls on
    ecoregion boundaries than in the east. The Kuchler system has the
    greatest number of ecoregions on all three transects, but does not
    necessarily have the highest degree of internal consistency within
    its ecoregions with regard to the bioclimatic and species richness
    data. In general, the WWF system appears to track climatic and floristic
    variables the best of the three systems, but not in all regions on
    all transects.
    BibTeX:
    @article{Thompson2004,
      author = {Thompson, RS and Shafer, SL and Anderson, KH and Strickland, LE and Pelltier, RT and Bartlein, PJ and Kerwin, MW},
      title = {Topographic, bioclimatic, and vegetation characteristics of three ecoregion classification systems in North America: Comparisons along continent-wide transects},
      journal = {Environmental Management},
      year = {2004},
      volume = {34},
      pages = {S125-S148--S125-S148}
    }
    					
    Whitlock2004 Whitlock, C.; Skinner, C.N.; Bartlein, P.J.; Minckley, T. & Mohr, J.A. Comparison of charcoal and tree-ring records of recent fires in the eastern Klamath Mountains, California, USA 2004 Canadian Journal of Forest Research
    Vol. 34 (10) , pp. 2110-2121  
    article
    Abstract: Fire-history reconstructions are based on tree-ring records that span
    the last few centuries and charcoal data from lake-sediment cores
    that extend back several thousand years. The two approaches have
    unique strengths and weaknesses in their ability to depict past fire
    events and fire regimes, and most comparisons of these datasets in
    western conifer forests have focused on sites characterized by high-severity
    crown fires. Tree-ring and charcoal data spanning the last 300 years
    in four watersheds in the montane forests of the Klamath Mountains
    provided an opportunity to compare the records in a fire regime of
    frequent low- to moderate-severity surface events. The charcoal data
    were obtained from small lakes, and tree-ring records were derived
    from fire-scar chronologies at multiple sites within each watershed.
    The comparison indicates that the tree-ring records detected individual
    fires not evident in the lake-sediment profiles, whereas the charcoal
    data disclosed variations in fuel loading and general levels of burning
    at broader spatial scales. Regional burning in the late 19th and
    early 20th centuries was evident in the lake-sediment records, and
    both datasets registered a decline in fire activity in the late 20th
    century. Thus, the two types of data provide complementary as well
    as supplementary information on past fire conditions.
    BibTeX:
    @article{Whitlock2004,
      author = {Whitlock, C and Skinner, CN and Bartlein, PJ and Minckley, T and Mohr, JA},
      title = {Comparison of charcoal and tree-ring records of recent fires in the eastern Klamath Mountains, California, USA},
      journal = {Canadian Journal of Forest Research},
      year = {2004},
      volume = {34},
      number = {10},
      pages = {2110--2121}
    }
    					
    Whitlock2004a Whitlock, C. & Bartlein, P.J. Gillespie, A.R.; Porter, S.C. & Atwater, B.F. (Hrsg.) Holocene fire activity as a record of past environmental change ( The Quaternary Period in the United States ) 2004 The Quaternary Period in the United States , pp. 479-490   inbook
    BibTeX:
    @inbook{Whitlock2004a,
      author = {Whitlock, C and Bartlein, PJ},
      title = {The Quaternary Period in the United States},
      publisher = {Elsevier, Amsterdam},
      year = {2004},
      pages = {479-490}
    }
    					
    Williams2004 Williams, J.W.; Shuman, B.N.; Webb, T.; Bartlein, P.J. & Leduc, P.L. Late-Quaternary vegetation dynamics in North America: Scaling from taxa to biomes 2004 Ecological Monographs
    Vol. 74 (2) , pp. 309-334  
    article paleoecology and paleoclimatology
    Abstract: This paper integrates recent efforts to map the distribution of biomes
    for the late Quaternary with the detailed evidence that plant species
    have responded individualistically to climate change at millennial
    timescales. Using a fossil-pollen data set of over 700 sites, we
    review late-Quaternary vegetation history in northern and eastern
    North America across levels of ecological organization from individual
    taxa to biomes, and apply the insights gained from this review to
    critically examine the biome maps generated from the pollen data.
    Higher-order features of the vegetation (e.g., plant associations,
    physiognomy) emerge from individualistic responses of plant taxa
    to climate change, and different representations of vegetation history
    reveal different aspects of vegetation dynamics. Vegetation distribution
    and composition were relatively stable during full-glacial times
    (2100017 000 yr BP) [calendar years] and during the mid- to late
    Holocene (7000-500 yr BP), but changed rapidly during the late-glacial
    period and early Holocene (16000-.8000 yr BP) and after 500 yr BP
    Shifts in plant taxon distributions were characterized by individualistic
    changes in population abundances and ranges and included large east-west
    shifts in distribution in addition to the northward redistribution
    of most taxa. Modern associations such as Fagus-Tsuga and Picea-Alnus-Betula
    date to the early Holocene, whereas other associations common to
    the late-glacial period (e.g., Picea-Cyperaceae-Fraxinus-Ostrya/
    Carpinus). no longer exist. Biomes are dynamic entities that have
    changed in distribution, composition; and structure over time. The
    late-Pleistocene suite of biomes is distinct from those that grew
    during the Holocene. The pollen-based biome reconstructions are able
    to capture the major features of late-Quaternary vegetation but downplay
    the magnitude and variety of vegetational responses to climate change
    by (1) limiting, apparent land-cover change to ecotones, (2) masking
    internal variations in biome composition, and (3) obscuring the range
    shifts and changes in abundance among individual taxa. The compositional
    and structural differences between full-glacial and recent biomes
    of the same type are. similar to or greater than the spatial heterogeneity
    in the composition and structure of present-day biomes. This spatial
    and temporal heterogeneity allows biome maps to accommodate individualistic
    behavior among species but masks climatically important variations
    in taxonomic composition as well as structural differences between
    modern biomes and their ancient counterparts.
    BibTeX:
    @article{Williams2004,
      author = {Williams, JW and Shuman, BN and Webb, T and Bartlein, PJ and Leduc, PL},
      title = {Late-Quaternary vegetation dynamics in North America: Scaling from taxa to biomes},
      journal = {Ecological Monographs},
      year = {2004},
      volume = {74},
      number = {2},
      pages = {309--334}
    }
    					
    Bartlein2003 Bartlein, P.J.; Hostetler, S.W.; Shafer, S.L.; Holman, J.O. & Solomon, A.M. The seasonal cycle of wildfire and climate in the western United States 2003 5th Symposium on Fire and Forest Meteorology, American Meteorological Society , pp. P3.9-1 - P3.9-6   inproceedings
    BibTeX:
    @inproceedings{Bartlein2003,
      author = {Bartlein, PJ and Hostetler, SW and Shafer, SL and Holman, JO and Solomon, AM},
      title = {The seasonal cycle of wildfire and climate in the western United States},
      booktitle = {5th Symposium on Fire and Forest Meteorology, American Meteorological Society},
      year = {2003},
      pages = {P3.9-1 - P3.9-6}
    }
    					
    Bigelow2003 Bigelow, N.H.; Brubaker, L.B.; Edwards, M.E.; Harrison, S.P.; Prentice, I.C.; Anderson, P.M.; Andreev, A.A.; Bartlein, P.J.; Christensen, T.R.; Cramer, W.; Kaplan, J.O.; Lozhkin, A.V.; Matveyeva, N.V.; Murray, D.F.; McGuire, A.D.; Razzhivin, V.Y.; Ritchie, J.C.; Smith, B.; Walker, D.A.; Gajewski, K.; Wolf, V.; Holmqvist, B.H.; Igarashi, Y.; Kremenetskii, K.; Paus, A.; Pisaric, M.F.J. & Volkova, V.S. Climate change and Arctic ecosystems: 1. Vegetation changes north of 55 degrees N between the last glacial maximum, mid-Holocene, and present 2003 Journal of Geophysical Research-Atmospheres
    Vol. 108 (D19) , pp. -  
    article vegetation and climate
    Abstract: [1] A unified scheme to assign pollen samples to vegetation types
    was used to reconstruct vegetation patterns north of 55degreesN at
    the last glacial maximum (LGM) and mid-Holocene (6000 years B. P.).
    The pollen data set assembled for this purpose represents a comprehensive
    compilation based on the work of many projects and research groups.
    Five tundra types (cushion forb tundra, graminoid and forb tundra,
    prostrate dwarf-shrub tundra, erect dwarf-shrub tundra, and low-
    and high-shrub tundra) were distinguished and mapped on the basis
    of modern pollen surface samples. The tundra-forest boundary and
    the distributions of boreal and temperate forest types today were
    realistically reconstructed. During the mid-Holocene the tundra-forest
    boundary was north of its present position in some regions, but the
    pattern of this shift was strongly asymmetrical around the pole,
    with the largest northward shift in central Siberia (similar to200
    km), little change in Beringia, and a southward shift in Keewatin
    and Labrador (similar to200 km). Low- and high-shrub tundra extended
    farther north than today. At the LGM, forests were absent from high
    latitudes. Graminoid and forb tundra abutted on temperate steppe
    in northwestern Eurasia while prostrate dwarf-shrub, erect dwarf-shrub,
    and graminoid and forb tundra formed a mosaic in Beringia. Graminoid
    and forb tundra is restricted today and does not form a large continuous
    biome, but the pollen data show that it was far more extensive at
    the LGM, while low- and high-shrub tundra were greatly reduced, illustrating
    the potential for climate change to dramatically alter the relative
    areas occupied by different vegetation types.
    BibTeX:
    @article{Bigelow2003,
      author = {Bigelow, NH and Brubaker, LB and Edwards, ME and Harrison, SP and Prentice, IC and Anderson, PM and Andreev, AA and Bartlein, PJ and Christensen, TR and Cramer, W and Kaplan, JO and Lozhkin, AV and Matveyeva, NV and Murray, DF and McGuire, AD and Razzhivin, VY and Ritchie, JC and Smith, B and Walker, DA and Gajewski, K and Wolf, V and Holmqvist, BH and Igarashi, Y and Kremenetskii, K and Paus, A and Pisaric, MFJ and Volkova, VS},
      title = {Climate change and Arctic ecosystems: 1. Vegetation changes north of 55 degrees N between the last glacial maximum, mid-Holocene, and present},
      journal = {Journal of Geophysical Research-Atmospheres},
      year = {2003},
      volume = {108},
      number = {D19},
      pages = {--}
    }
    					
    Diffenbaugh2003 Diffenbaugh, N.S.; Sloan, L.C.; Snyder, M.A.; Bell, J.L.; Kaplan, J.; Shafer, S.L. & Bartlein, P.J. Vegetation sensitivity to global anthropogenic carbon dioxide emissions in a topographically complex region 2003 Global Biogeochemical Cycles
    Vol. 17 (2) , pp. -  
    article future vegetation changes
    Abstract: [1] Anthropogenic increases in atmospheric carbon dioxide (CO2) concentrations
    may affect vegetation distribution both directly through changes
    in photosynthesis and water-use efficiency, and indirectly through
    CO2-induced climate change. Using an equilibrium vegetation model
    (BIOME4) driven by a regional climate model (RegCM2.5), we tested
    the sensitivity of vegetation in the western United States, a topographically
    complex region, to the direct, indirect, and combined effects of
    doubled preindustrial atmospheric CO2 concentrations. Those sensitivities
    were quantified using the kappa statistic. Simulated vegetation in
    the western United States was sensitive to changes in atmospheric
    CO2 concentrations, with woody biome types replacing less woody types
    throughout the domain. The simulated vegetation was also sensitive
    to climatic effects, particularly at high elevations, due to both
    warming throughout the domain and decreased precipitation in key
    mountain regions such as the Sierra Nevada of California and the
    Cascade and Blue Mountains of Oregon. Significantly, when the direct
    effects of CO2 on vegetation were tested in combination with the
    indirect effects of CO2-induced climate change, new vegetation patterns
    were created that were not seen in either of the individual cases.
    This result indicates that climatic and nonclimatic effects must
    be considered in tandem when assessing the potential impacts of elevated
    CO2 levels.
    BibTeX:
    @article{Diffenbaugh2003,
      author = {Diffenbaugh, NS and Sloan, LC and Snyder, MA and Bell, JL and Kaplan, J and Shafer, SL and Bartlein, PJ},
      title = {Vegetation sensitivity to global anthropogenic carbon dioxide emissions in a topographically complex region},
      journal = {Global Biogeochemical Cycles},
      year = {2003},
      volume = {17},
      number = {2},
      pages = {--}
    }
    					
    Fonstad2003 Fonstad, M. & Marcus, W.A. Self-organized criticality in riverbank systems 2003 Annals of the Association of American Geographers
    Vol. 93 (2) , pp. 281-296  
    article fluvial geomorphology
    Abstract: Where and when do natural rivers become unstable? To answer this question,
    we visually estimated bank-failure extent in 100-m increments along
    180 km of riverbanks in three watersheds of the northern Yellowstone
    ecosystem. The riverbank data reveal precise power-law relationships
    between the number of bank failures of a given size throughout each
    watershed and the magnitude of those bank failures. The slopes of
    log-log graphs (i.e., the exponent tau) of bank-failure magnitude
    versus failure frequency in alluvial reaches vary from 1.07 to 1.44,
    while tau for all reaches combined (alluvial, colluvial, and bedrock)
    varies from 1.18 to 1.53, suggesting that lower-gradient, alluvial
    streams are more susceptible to large bank failures. Cellular automata
    simulations of riverbanks show similar power-law failure relationships,
    as do bank-erosion data from a long-term independent dataset from
    another location. These power-law structures can be interpreted as
    the spatial signal of a self-organized critical (SOC) system, in
    which local instabilities function to generate broader-scale order.
    SOC systems are considered to be at the "edge of chaos," where local
    processes interact to make prediction of specific failure events
    impossible, although probability distribution prediction of the magnitude
    and spatial frequency of those events is possible. A critical structure
    of this sort is to be expected in bank failures along a stream given
    a nonlinear diffusive system such as a drainage basin. If riverbanks
    are, in fact, part of a critical system, then long-term local or
    watershed-wide stability is an unlikely or even impossible engineering
    or restoration goal. The existence of criticality in natural stream
    settings suggests that local human alterations designed to increase
    channel stability, while changing the local frequency of small failures,
    will only encourage an increase in the magnitude of system-wide,
    low-frequency large failures. A restoration or stabilization effort
    will not eliminate the bank instability. Instead, it will transfer
    that instability to neighboring riverbank areas.
    BibTeX:
    @article{Fonstad2003,
      author = {Fonstad, M and Marcus, WA},
      title = {Self-organized criticality in riverbank systems},
      journal = {Annals of the Association of American Geographers},
      year = {2003},
      volume = {93},
      number = {2},
      pages = {281--296}
    }
    					
    Fonstad2003a Fonstad, M.A. Spatial variation in the power of mountain streams in the Sangre de Cristo Mountains, New Mexico 2003 Geomorphology
    Vol. 55 (1-4) , pp. 75-96  
    article alluvial channel, bank, continuum, discharge, erosion, geomorphic processes, hydraulic geometry, pattern, river, rocky mountains, simultaneous-equation models, stream power, variability, vegetation
    Abstract: The principle indicator of river energy expenditure, stream power,
    has a significant influence on many forms and process attributes
    of the fluvial system, yet few basin-wide analyses of stream power
    variations have ever been conducted. Recent studies hypothesize a
    peak in the mean stream power distribution in small (10 km(2))- to
    intermediate (100 km(2))-sized basins. To test hypothetical stream
    power profiles in a high mountain setting, 129 cross-sections of
    stream networks within the Costilla basin of northern New Mexico
    and southern Colorado were measured for channel form, local sediment
    conditions, and basin characteristics. Geomorphic and hydrologic
    analysis of these river sites throughout the Costilla basin yielded
    evidence of abundant local control over fluvial processes and forms.
    Within the basin, the spatial deviations of stream power from the
    hypothetical patterns derived from hydraulic geometry, in some cases
    textgreater200% deviation, match areas of specific geologic and
    hydrogeologic control. As an alternative to traditional hydraulic
    descriptions of downstream channel form, a probabilistic process-response
    model can incorporate local and basin-scale variables and allow more
    realistic feedback mechanisms than in traditional regime theory.
    The probabilistic nature of this type of model also allows prediction
    of multiple modes of channel adjustment, an ever-present challenge
    to extremal and physically based simulations. (C) 2003 Elsevier Science
    B.V. All rights reserved.
    BibTeX:
    @article{Fonstad2003a,
      author = {Fonstad, M. A.},
      title = {Spatial variation in the power of mountain streams in the Sangre de Cristo Mountains, New Mexico},
      journal = {Geomorphology},
      year = {2003},
      volume = {55},
      number = {1-4},
      pages = {75--96},
      doi = {http://doi.org/10.1016/S0169-555X(03)00133-8}
    }
    					
    Gavin2003 Gavin, D.G.; Oswald, W.W.; Wahl, E.R. & Williams, J.W. A statistical approach to evaluating distance metrics and analog assignments for pollen records 2003 Quaternary Research
    Vol. 60 (3) , pp. 356-367  
    article modern climate analoguesm
    Abstract: The modern analog technique typically uses a distance metric to determine
    the dissimilarity between fossil and modern biological assemblages.
    Despite this quantitative approach, interpretation of distance metrics
    is usually qualitative and rules for selection of analogs tend to
    be ad hoe. We present a statistical tool, the receiver operating
    characteristic (ROC) curve, which provides a framework for identifying
    analogs from distance metrics. If modern assemblages are placed into
    groups (e.g., biomes), this method can (1) evaluate the ability of
    different distance metrics to distinguish among groups, (2) objectively
    identify thresholds of the distance metric for determining analogs,
    and (3) compute a likelihood ratio and a Bayesian probability that
    a modern group is an analog for an unknown (fossil) assemblage. Applied
    to a set of 1689 modern pollen assemblages from eastern North America
    classified into eight biomes, ROC analysis confirmed that the squared-chord
    distance (SCD) outperforms most other distance metrics. The optimal
    threshold increased when more dissimilar biomes were compared. The
    probability of an analog vs no-analog result (a likelihood ratio)
    increased sharply when SCD decreased below the optimal threshold,
    indicating a nonlinear relationship between SCD and the probability
    of analog. Probabilities of analog computed for a postglacial pollen
    record at Tannersville Bog (Pennsylvania, USA) identified transitions
    between biomes and periods of no analog. (C) 2003 Elsevier Science
    (USA). Published by Elsevier Inc. All rights reserved.
    BibTeX:
    @article{Gavin2003,
      author = {Gavin, DG and Oswald, WW and Wahl, ER and Williams, JW},
      title = {A statistical approach to evaluating distance metrics and analog assignments for pollen records},
      journal = {Quaternary Research},
      year = {2003},
      volume = {60},
      number = {3},
      pages = {356--367}
    }
    					
    Gavin2003a Gavin, D.G.; Brubaker, L.B. & Lertzman, K.P. An 1800-year record of the spatial and temporal distribution of fire from the west coast of Vancouver Island, Canada 2003 Canadian Journal of Forest Research
    Vol. 33 (4) , pp. 573-586  
    article
    Abstract: Charcoal records from lake sediments may show changes in fire frequency
    over thousands of years, but such records are ambiguous with regard
    to the actual locations of fires. Using a comparison of fire dates
    from an 1800-year lake sediment record from the west coast of Vancouver
    Island (British Columbia, Canada) and dates of last fire from 38
    sites in the same watershed using tree-ring and soil-charcoal C-14
    dates, we estimated the source area that contributes to charcoal
    peaks and determined the degree to which fires were biased to certain
    locations. Twenty-three charcoal peaks, likely corresponding with
    individual fire events, were objectively identified from the sediment
    record. Comparison of fire dates from charcoal peaks in the sediment
    record with fire dates from points near the lake suggests that the
    charcoal source area is within 500 m of the lake edge. Fire occurrence
    within this charcoal source area increased sharply at AD 1100 from
    ca. 50 to ca. 300 years between charcoal peaks, coeval with the first
    "Little Ice Age" cooling. Soil-charcoal radiocarbon dates revealed
    that 37% of the charcoal source area had not burned over the last
    1800 years and that the 23 fires identified in the sediment record
    were restricted to south-facing slopes near the lake. This spatial
    pattern may result only if fire is >25 times more likely to occur
    on susceptible sites (south-facing slopes) than on less susceptible
    sites. This strong bias in fire location ensured the millennial-scale
    persistence of large areas of late-successional forest through past
    climatic periods.
    BibTeX:
    @article{Gavin2003a,
      author = {Gavin, DG and Brubaker, LB and Lertzman, KP},
      title = {An 1800-year record of the spatial and temporal distribution of fire from the west coast of Vancouver Island, Canada},
      journal = {Canadian Journal of Forest Research},
      year = {2003},
      volume = {33},
      number = {4},
      pages = {573--586}
    }
    					
    Gavin2003b Gavin, D.G.; Brubaker, L.B. & Lertzman, K.P. Holocene fire history of a coastal temperate rain forest based on soil charcoal radiocarbon dates 2003 Ecology
    Vol. 84 (1) , pp. 186-201  
    article
    Abstract: The long-term role of fire in coastal temperate rain forest is poorly
    understood. To determine the historical role of fire on western Vancouver
    Island (British Columbia, Canada), we constructed a long-term spatially
    explicit fire history and examined the spatial and temporal distribution
    of fire during the Holocene. Two fire-history parameters (time-since-fire
    [TSF] and fire extent) were related to three landscape parameters
    landform [hill slope or terrace]. aspect, and forest composition)
    at 83 sites in a 730-ha low-elevation (less than similar to200 m)
    area of a mountainous watershed. We dated fires using tree rings
    ( 18 sites) and 120 soil-charcoal radiocarbon dates (65 sites). Comparisons
    among multiple radiocarbon dates indicated a high probability that
    the charcoal dated at each site represented the most recent fire,
    though we expect greater error in TSF estimates at sites where charcoal
    was very old (>6000 yr) and was restricted to mineral soil horizons.
    TSF estimates ranged from 64 to similar to12 220 yr; 45% of the sites
    have burned in the last 1000 yr, whereas 2017( of the sites have
    not burned for over 6000 yr. Differences in median TSF were more
    significant between landform types or across aspects than among forest
    types, Median TSF was significantly greater on terraces (4410 yr)
    than on hill slopes (740 yr). On hill slopes. all south-facing and
    southwest-facing sites have burned within the last 1000 yr compared
    to only 27% of north- and east-facing sites burning over the same
    period. Comparison of fire dates among neighboring sites indicated
    that fires rarely extended >250 m. During the late Holocene, landform
    controls have been strong. resulting in the bias of fires to south-facing
    hillslopes and thus allowing late-successional forest structure to
    persist for thousands of years in a large portion of the watershed.
    In contrast, the early Holocene regional climate and forest composition
    likely resulted in larger landscape tires that were not strongly
    controlled by landform factors. The millennial-scale TSF detected
    in this study supports the distinction of coastal temperate rain
    forest as being under a fundamentally different disturbance regime
    than other Pacific Northwest forests to the cast and south.
    BibTeX:
    @article{Gavin2003b,
      author = {Gavin, DG and Brubaker, LB and Lertzman, KP},
      title = {Holocene fire history of a coastal temperate rain forest based on soil charcoal radiocarbon dates},
      journal = {Ecology},
      year = {2003},
      volume = {84},
      number = {1},
      pages = {186--201}
    }
    					
    Gavin2003c Gavin, D.G. Forest soil disturbance intervals inferred from soil charcoal radiocarbon dates 2003 Canadian Journal of Forest Research
    Vol. 33 (12) , pp. 2514-2518  
    article
    Abstract: Forest soil disturbance intervals are usually too long to measure
    using plot-based studies, and thus they are poorly understood. The
    mean soil disturbance interval (MSDI) in an old-growth forest on
    the west coast of Vancouver Island was estimated from radiocarbon
    dates of charcoal from organic and mineral soil horizons. Two assumptions
    are required to estimate the MSDI: (1) charcoal from forest fires
    is deposited within the organic horizon and eventually mixed into
    deeper mineral horizons by soil disturbances, and (2) the probability
    of soil disturbance is spatially homogeneous and affected only by
    the time since the last fire or the last soil disturbance. The MSDI
    is then estimated by the rate at which the proportion of undisturbed
    sample sites (determined by the proportion of sites with charcoal
    from the most recent fire in the organic horizon) decreases with
    increasing time since the last fire. Soil charcoal evidence of time
    since fire was determined at 83 sites using 141 radiocarbon dates.
    The estimated MSDI was greater on slopes (ca. 2010 years) than on
    terraces (ca. 920 years). The long periods between soil disturbances,
    especially on slopes, are consistent with other evidence from the
    study area that suggests infrequent tree uprooting is the predominant
    mode of soil disturbance.
    BibTeX:
    @article{Gavin2003c,
      author = {Gavin, DG},
      title = {Forest soil disturbance intervals inferred from soil charcoal radiocarbon dates},
      journal = {Canadian Journal of Forest Research},
      year = {2003},
      volume = {33},
      number = {12},
      pages = {2514--2518}
    }
    					
    Harrison2003 Harrison, S.P.; Kutzbach, J.E.; Liu, Z.; Bartlein, P.J.; Otto-Bliesner, B.; Muhs, D.; Prentice, I.C. & Thompson, R.S. Mid-Holocene climates of the Americas: a dynamical response to changed seasonality 2003 Climate Dynamics
    Vol. 20 (7-8) , pp. 663-688  
    article paleoclimatic analysis and data-model comparisons
    Abstract: Simulations of the climatic response to mid-Holocene (6 ka BP) orbital
    forcing with two coupled ocean-atmosphere models (FOAM and CSM) show
    enhancement of monsoonal precipitation in parts of the American Southwest.
    Central America and northernmost South America during Northern Hemisphere
    summer. The enhanced onshore flow that brings precipitation into
    Central America is caused by a northward displacement of the inter-tropical
    convergence zone, driven by cooling of the equatorial and warming
    of the northern subtropical and mid-latitude ocean. Ocean feedbacks
    also enhance precipitation over the American Southwest, although
    the increase in monsoon precipitation there is largely driven by
    increases in land-surface temperature. The northward shift in the
    equatorial precipitation band that causes enhanced precipitation
    in Central America and the American Southwest has a negative feedback
    effect on monsoonal precipitation in northern South America. The
    simulations demonstrate that mid-Holocene aridity in the mid-continent
    of North America is dynamically linked to the orbitally induced enhancement
    of the summer monsoon in the American Southwest, with a spatial structure
    (wet in the Southwest and dry in the mid-continent) similar to that
    found in strong monsoon years today. Changes in winter precipitation
    along the west coast of North America, in Central America and along
    the Gulf Coast, caused by southward-displacement of the westerly
    storm tracks, indicate that changes in the Northern Hemisphere winter
    monsoon also play a role in regional climate changes during the mid-Holocene.
    Although the simulations with FOAM and CSM differ in detail, the
    general mechanisms and patterns are common to both. The model results
    thus provide a coherent dynamical explanation for regional patterns
    of increased or decreased aridity shown by vegetation, lake status
    and aeolian data from the Americas.
    BibTeX:
    @article{Harrison2003,
      author = {Harrison, SP and Kutzbach, JE and Liu, Z and Bartlein, PJ and Otto-Bliesner, B and Muhs, D and Prentice, IC and Thompson, RS},
      title = {Mid-Holocene climates of the Americas: a dynamical response to changed seasonality},
      journal = {Climate Dynamics},
      year = {2003},
      volume = {20},
      number = {7-8},
      pages = {663--688}
    }
    					
    Hostetler2003 Hostetler, S.W.; Bartlein, P.J.; Holman, J.O.; Shafer, S.L. & Solomon, A.M. Using a regional climate model to diagnose climatological and meterological controls of wildfire in the western United States 2003 5th Symposium on Fire and Forest Meteorology. American Meteorological Society , pp. P1.3-1 - P1.3-5   inproceedings
    BibTeX:
    @inproceedings{Hostetler2003,
      author = {Hostetler, SW and Bartlein, PJ and Holman, JO and Shafer, SL and Solomon, AM},
      title = {Using a regional climate model to diagnose climatological and meterological controls of wildfire in the western United States},
      booktitle = {5th Symposium on Fire and Forest Meteorology. American Meteorological Society},
      year = {2003},
      pages = {P1.3-1 - P1.3-5}
    }
    					
    Kaplan2003 Kaplan, J.O.; Bigelow, N.H.; Prentice, I.C.; Harrison, S.P.; Bartlein, P.J.; Christensen, T.R.; Cramer, W.; Matveyeva, N.V.; McGuire, A.D.; Murray, D.F.; Razzhivin, V.Y.; Smith, B.; Walker, D.A.; Anderson, P.M.; Andreev, A.A.; Brubaker, L.B.; Edwards, M.E. & Lozhkin, A.V. Climate change and Arctic ecosystems: 2. Modeling, paleodata-model comparisons, and future projections 2003 Journal of Geophysical Research-Atmospheres
    Vol. 108 (D19) , pp. -  
    article vegetation and climate
    Abstract: [1] Large variations in the composition, structure, and function of
    Arctic ecosystems are determined by climatic gradients, especially
    of growing-season warmth, soil moisture, and snow cover. A unified
    circumpolar classification recognizing five types of tundra was developed.
    The geographic distributions of vegetation types north of 55degreesN,
    including the position of the forest limit and the distributions
    of the tundra types, could be predicted from climatology using a
    small set of plant functional types embedded in the biogeochemistry-biogeography
    model BIOME4. Several palaeoclimate simulations for the last glacial
    maximum (LGM) and mid-Holocene were used to explore the possibility
    of simulating past vegetation patterns, which are independently known
    based on pollen data. The broad outlines of observed changes in vegetation
    were captured. LGM simulations showed the major reduction of forest,
    the great extension of graminoid and forb tundra, and the restriction
    of low- and high-shrub tundra (although not all models produced sufficiently
    dry conditions to mimic the full observed change). Mid-Holocene simulations
    reproduced the contrast between northward forest extension in western
    and central Siberia and stability of the forest limit in Beringia.
    Projection of the effect of a continued exponential increase in atmospheric
    CO2 concentration, based on a transient ocean-atmosphere simulation
    including sulfate aerosol effects, suggests a potential for larger
    changes in Arctic ecosystems during the 21st century than have occurred
    between mid-Holocene and present. Simulated physiological effects
    of the CO2 increase (to >700 ppm) at high latitudes were slight compared
    with the effects of the change in climate.
    BibTeX:
    @article{Kaplan2003,
      author = {Kaplan, JO and Bigelow, NH and Prentice, IC and Harrison, SP and Bartlein, PJ and Christensen, TR and Cramer, W and Matveyeva, NV and McGuire, AD and Murray, DF and Razzhivin, VY and Smith, B and Walker, DA and Anderson, PM and Andreev, AA and Brubaker, LB and Edwards, ME and Lozhkin, AV},
      title = {Climate change and Arctic ecosystems: 2. Modeling, paleodata-model comparisons, and future projections},
      journal = {Journal of Geophysical Research-Atmospheres},
      year = {2003},
      volume = {108},
      number = {D19},
      pages = {--}
    }
    					
    Legleiter2003 Legleiter, C.J.; Lawrence, R.L.; Fonstad, M.A.; Marcus, W.A. & Aspinall, R. Fluvial response a decade after wildfire in the northern Yellowstone ecosystem: a spatially explicit analysis 2003 Geomorphology
    Vol. 54 (3-4) , pp. 119-136  
    article fluvial geomorphology
    Abstract: Forest fire is a vital ecological process capable of inducing complex
    fluvial response, but the integration of these effects across entire
    watersheds remains poorly understood. We collected downstream cross-sectional
    and geomorphic data, acquired geographic information on land cover
    and forest fire, and performed spatially explicit statistical analyses
    to examine fire-related impacts in catchments burned to varying degrees.
    Generalized least squares (GLS) regression models suggested that
    channels with a greater percentage of burned drainage area were associated
    with markedly higher cross-sectional stream power, relatively smaller
    width/depth ratios, and lower bank failure rates 12 to 13 years after
    the fires. These results implied that streams became more powerful
    in the aftermath of forest fire and that net incision had been the
    primary response in second- to fourth-order channels since the 1988
    Yellowstone fires. The extensive geographic coverage of our data,
    spanning multiple basins with measurements spaced every 100 m, allowed
    us to hypothesize a process-response model based on these results.
    We suggest that a wave of fire-related sediment propagates through
    burned catchments. High runoff events or even moderate flows provide
    sufficient energy to evacuate the finer-grained material delivered
    from burned hillslopes to the channel network over a period of 5-10
    years. The combination of elevated post-fire discharges and decreased
    sediment supply then induces an episode of incision. Site-specific
    channel changes are highly variable because streams can accommodate
    post-fire increases in energy and sediment supply through multiple
    modes of adjustment. Characterizing the spatial distribution of stream
    power would provide a valuable management tool because this variable
    is strongly associated with percent-burned drainage area and integrates
    several elements of complex fluvial response. Future research focused
    on the channel substrate and its evolution through time is needed,
    but our results indicate a fundamental linkage between fire and fluvial
    processes. (C) 2002 Elsevier Science B.V. All rights reserved.
    BibTeX:
    @article{Legleiter2003,
      author = {Legleiter, CJ and Lawrence, RL and Fonstad, MA and Marcus, WA and Aspinall, R},
      title = {Fluvial response a decade after wildfire in the northern Yellowstone ecosystem: a spatially explicit analysis},
      journal = {Geomorphology},
      year = {2003},
      volume = {54},
      number = {3-4},
      pages = {119--136}
    }
    					
    Lynch2003 Lynch, A.H.; Rivers, A.R. & Bartlein, P.J. An assessment of the influence of land cover uncertainties on the simulation of global climate in the early Holocene 2003 Climate Dynamics
    Vol. 21 (3-4) , pp. 243-256  
    article paleoclimatic analysis and data-model comparisons
    Abstract: Six and 21 kyear BP represent the extreme states of climate since
    the last glacial maximum. The early Holocene, in contrast, was a
    time of transition, experiencing rapidly melting continental ice
    sheets, rising sea-level, and increasing summer insolation. Key features
    of the climate, illustrated by an NCAR CCM3 general circulation model
    experiment representing 11 kyr BP, include enhanced continentality
    and seasonality, and an enhanced northern monsoon. The principal
    circulation responses to the 11 kyr BP boundary conditions can be
    summarized as an intensification and northward shift of the mean
    meridional circulation and an intensification of the planetary wave
    structure of the Northern Hemisphere in northern summer, and a slight
    intensification of the mean meridional circulation coupled with a
    southward shift in the planetary wave structure in northern winter.
    These changes are manifest in the enhancement of the typical seasonal
    cycle of sea-level pressure in the Northern Hemisphere relative to
    that of the present day, and enhancement and equatorward shift of
    the Aleutian and Icelandic lows in northern winter. Over the period
    15-8 kyr BP, within the current boreal forest zone, herbaceous tundra
    was replaced by shrub tundra, and subsequently by evergreen or deciduous
    forest, but there is uncertainty in the location, timing, and exact
    nature of these transitions. The specific location of the relatively
    small area of the Asian boreal forest-tundra transition can have
    an impact on regional climate, primarily in the net shortwave radiation
    component of the surface energy budget in spring, and in the cloudiness,
    net shortwave radiation, and turbulent heat fluxes in summer. These
    changes also have an impact on global climate. Our results suggest
    that the additional northern heating leads to a reduced equator-pole
    heat transport in the Northern Hemisphere which then influences heat
    and momentum transport in the Southern Hemisphere.
    BibTeX:
    @article{Lynch2003,
      author = {Lynch, AH and Rivers, AR and Bartlein, PJ},
      title = {An assessment of the influence of land cover uncertainties on the simulation of global climate in the early Holocene},
      journal = {Climate Dynamics},
      year = {2003},
      volume = {21},
      number = {3-4},
      pages = {243--256}
    }
    					
    Marcus2003 Marcus, W.A.; Legleiter, C.J.; Aspinall, R.J.; Boardman, J.W. & Crabtree, R.L. High spatial resolution hyperspectral mapping of in-stream habitats, depths, and woody debris in mountain streams 2003 Geomorphology
    Vol. 55 (1-4) , pp. 363-380  
    article
    Abstract: This article evaluates the potential of I-m resolution, 128-band hyperspectral
    imagery for mapping in-stream habitats, depths, and woody debris
    in third- to fifth-order streams in the northern Yellowstone region.
    Maximum likelihood supervised classification using principal component
    images provided overall classification accuracies for in-stream habitats
    (glides, riffles, pools, and eddy drop zones) ranging from 69% for
    third-order streams to 86% for fifth-order streams. This scale dependency
    of classification accuracy was probably driven by the greater proportion
    of transitional boundary areas in the smaller streams. Multiple regressions
    of measured depths (y) versus principal component scores (x(1), x(2),...,
    x(n)) generated R-2 values ranging from 67% for high-gradient riffles
    to 99% for glides in a fifth-order reach. R 2 values were lower in
    third-order reaches, ranging from 28% for runs and glides to 94%
    for pools. The less accurate depth estimates obtained for smaller
    streams probably resulted from the relative increase in the number
    of mixed pixels, where a wide range of depths and surface turbulence
    occurred within a single pixel. Matched filter (MF) mapping of woody
    debris generated overall accuracies of 83% in the fifth-order Lamar
    River. Accuracy figures for the in-stream habitat and wood mapping
    may have been misleadingly low because the fine-resolution imagery
    captured fine-scale variations not mapped by field teams, which in
    turn generated false "misclassifications" when the image and field
    maps were compared. The use of high spatial resolution hyperspectral
    (HSRH) imagery for stream mapping is limited by the need for clear
    water to measure depth, by any tree cover obscuring the stream, and
    by the limited availability of airborne hyperspectral sensors. Nonetheless,
    the high accuracies achieved in northern Yellowstone streams indicate
    that HSRH imagery can be a powerful tool for watershed-wide mapping,
    monitoring, and modeling of streams. (C) 2003 Elsevier Science B.V.
    All rights reserved.
    BibTeX:
    @article{Marcus2003,
      author = {Marcus, WA and Legleiter, CJ and Aspinall, RJ and Boardman, JW and Crabtree, RL},
      title = {High spatial resolution hyperspectral mapping of in-stream habitats, depths, and woody debris in mountain streams},
      journal = {Geomorphology},
      year = {2003},
      volume = {55},
      number = {1-4},
      pages = {363--380}
    }
    					
    Oswald2003 Oswald, W.W.; Brubaker, L.B.; Hu, F.S. & Gavin, D.G. Pollen-vegetation calibration for tundra communities in the Arctic Foothills, northern Alaska 2003 Journal of Ecology
    Vol. 91 (6) , pp. 1022-1033  
    article
    Abstract: 1 Palynology has been portrayed as a 'blunt' tool for reconstructing
    variations in arctic tundra vegetation. We tested this characterization
    in the Arctic Foothills of northern Alaska by analysing 56 modern
    pollen assemblages from lakes on contrasting glaciated surfaces.
    The two surfaces, which date to the Sagavanirktok (> 125 000 years
    BP) and Itkillik II (c. 11 500 years BP) ice advances from the Brooks
    Range, have considerably different geomorphology, soil characteristics
    and plant communities. Sagavanirktok surfaces are dominated by dwarf-shrub
    tundra (DST), and Itkillik II surfaces by prostrate-shrub tundra
    (PST). 2 We used two multivariate approaches, dissimilarity metrics
    (squared chord distance and Canberra metric distance) and discriminant
    analysis, to assess the ability of the pollen data to distinguish
    between the Sagavanirktok and Itkillik II landscapes, and to identify
    the taxa most strongly associated with one surface or the other.
    Receiver operating characteristic (ROC) analysis was used to evaluate
    the performance of the dissimilarity metrics and to determine their
    'critical values' for distinguishing between assemblages from like
    and unlike plant communities. 3 According to the discriminant analysis,
    taxa indicative of the Sagavanirktok surface include Rubus chamaemorus,
    Sphagnum and Ericales, whereas Equisetum, Thalictrum and Polypodiaceae
    were faithful to the Itkillik II surface. These differences between
    the pollen assemblages make it possible to differentiate between
    the two landscapes using Canberra metric distance comparisons. The
    ROC analysis demonstrated that the Canberra metric distance is more
    effective than squared chord distance for distinguishing between
    the two surfaces. This study illustrates that palynology can be used
    to explore questions regarding the landscape-scale heterogeneity
    of past tundra vegetation.
    BibTeX:
    @article{Oswald2003,
      author = {Oswald, WW and Brubaker, LB and Hu, FS and Gavin, DG},
      title = {Pollen-vegetation calibration for tundra communities in the Arctic Foothills, northern Alaska},
      journal = {Journal of Ecology},
      year = {2003},
      volume = {91},
      number = {6},
      pages = {1022--1033}
    }
    					
    Whitlock2003 Whitlock, C.; Bartlein, P.J.; Marlon, J.; Brunelle, A. & Long, C. Holocene fire reconstructions from the northwestern U.S.: an examination at multiple time scales 2003 5th Symposium on Fire and Forest Meteorology. American Meteorological Society , pp. 4C.1-1 - 4C.1-5   inproceedings fire: paleo and modern
    BibTeX:
    @inproceedings{Whitlock2003,
      author = {Whitlock, C and Bartlein, PJ and Marlon, J and Brunelle, A and Long, C.},
      title = {Holocene fire reconstructions from the northwestern U.S.: an examination at multiple time scales},
      booktitle = {5th Symposium on Fire and Forest Meteorology. American Meteorological Society},
      year = {2003},
      pages = {4C.1-1 - 4C.1-5}
    }
    					
    Aspinall2002 Aspinall, R.J.; Marcus, W.A. & Boardman, J.W. Considerations in collecting, processing, and analyzing high spatial resolution, hyperspectral data for environmental investigations 2002 Journal of Geographical Systems
    Vol. 4 , pp. 15-29  
    article remote sensing
    BibTeX:
    @article{Aspinall2002,
      author = {Aspinall, RJ and Marcus, WA and Boardman, JW},
      title = {Considerations in collecting, processing, and analyzing high spatial resolution, hyperspectral data for environmental investigations},
      journal = {Journal of Geographical Systems},
      year = {2002},
      volume = {4},
      pages = {15-29}
    }
    					
    Jacquez2002 Jacquez, G.M.; Marcus, W.A.; Aspinall, R.J. & Greiling, D. Exposure assessment using high spatial resolution hyperspectral (HSRH) imagery 2002 Journal of Geographical Systems
    Vol. 4 , pp. 1-14  
    article remote sensing
    BibTeX:
    @article{Jacquez2002,
      author = {Jacquez, GM and Marcus, WA and Aspinall, RJ and Greiling, D},
      title = {Exposure assessment using high spatial resolution hyperspectral (HSRH) imagery},
      journal = {Journal of Geographical Systems},
      year = {2002},
      volume = {4},
      pages = {1-14}
    }
    					
    Legleiter2002 Legleiter, C.J.; Marcus, W.A. & Lawrence, R.L. Effects of sensor resolution on mapping in-stream habitats 2002 Photogrammetric Engineering and Remote Sensing
    Vol. 68 (8) , pp. 801-807  
    article
    Abstract: Effects of spatial, spectral, and radiometric resolution on remote
    mapping of fourth-order in-stream habitats were evaluated by comparing
    hyperspectral imagery to simulated multispectral data. Spectral resolution
    was more important than spatial or radiometric resolution in improving
    classification accuracies, although overall accuracies never exceeded
    62 percent. Overall accuracies were significantly greater for (1)
    hyperspectral data (7.2 percent) compared to simulated multispectral
    imagery, (2) 1-m pixels (4.7 percent) compared to 2.5-m pixels, and
    (3) 11-bit data (0.8 percent) compared to 8-bit data. Higher spatial
    resolution also enabled removal of transitional areas between units
    by using interior buffers, improving accuracy by up to 15.6 percent.
    We believe low overall accuracies were primarily due to the subjective
    and oversimplified nature of the polygon-bused field maps used as
    ground reference data, and high-resolution imagery might provide
    a more detailed representation of in-stream habitats. Improved methods
    of collecting ground reference data, utilizing a point-based approach,
    should be developed for assessing the accuracy of classifications
    derived from fine spatial resolution (less than 5-m) imagery.
    BibTeX:
    @article{Legleiter2002,
      author = {Legleiter, CJ and Marcus, WA and Lawrence, RL},
      title = {Effects of sensor resolution on mapping in-stream habitats},
      journal = {Photogrammetric Engineering and Remote Sensing},
      year = {2002},
      volume = {68},
      number = {8},
      pages = {801--807}
    }
    					
    Lertzman2002 Lertzman, K.; Gavin, D.; Hallett, D.; Brubaker, L.; Lepofsky, D. & Mathewes, R. Long-term fire regime estimated from soil charcoal in coastal temperate rainforests 2002 Conservation Ecology
    Vol. 6 (2) , pp. -  
    article
    Abstract: Coastal temperate rainforests from southeast Alaska through to southern
    Oregon are ecologically distinct from forests of neighboring regions,
    which have a drier, or more continental, climate and disturbance
    regimes dominated by fires. The long-term role of fire remains one
    of the key outstanding sources of uncertainty in the historical dynamics
    of the wetter and less seasonal forests that dominate the northerly
    two thirds of the rainforest region in British Columbia and Alaska.
    Here, we describe the long-term fire regime in two forests on the
    south coast of British Columbia by means of 244 AMS radiocarbon dates
    of charcoal buried in forest soils. In both forests, some sites have
    experienced no fire over the last 6000 years and many other sites
    have experienced only one or two fires during that time. Intervals
    between fires vary from a few centuries to several thousand years.
    In contrast to other conifer forests, this supports a model of forest
    dynamics where fires are of minor ecological importance. Instead,
    forest history is dominated by fine-scale processes of disturbance
    and recovery that maintain an ubiquitous late-successional character
    over the forest landscape. This has significant implications for
    ecosystem-based forest management and our understanding of carbon
    storage in forest soils.
    BibTeX:
    @article{Lertzman2002,
      author = {Lertzman, K and Gavin, D and Hallett, D and Brubaker, L and Lepofsky, D and Mathewes, R},
      title = {Long-term fire regime estimated from soil charcoal in coastal temperate rainforests},
      journal = {Conservation Ecology},
      year = {2002},
      volume = {6},
      number = {2},
      pages = {--}
    }
    					
    Marcus2002 Marcus, W.A.; Marston, R.A.; Colvard, C.R. & Gray, R.D. Mapping the spatial and temporal distributions of woody debris in streams of the Greater Yellowstone Ecosystem, USA 2002 Geomorphology
    Vol. 44 (3-4) , pp. 323-335  
    article
    Abstract: The objectives of this study were: (1) to document spatial and temporal
    distributions of large woody debris (LWD) at watershed scales and
    investigate some of the controlling processes; and (2) to judge the
    potential for mapping LWD accumulations with airborne multispectral
    imagery. Field surveys were conducted on the Snake River, Soda Butte
    Creek, and Cache Creek in the Greater Yellowstone Ecosystem, USA.
    The amount of woody debris per kilometer is highest in 2nd order
    streams, widely variable in 3rd and 4th order streams, and relatively
    low in the 6th order system. Floods led to increases in woody debris
    in 2nd order streams, Floods redistributed the wood in 3rd and 4th
    order streams, removing it from the channel and stranding it on bars,
    but appeared to generate little change in the total amount of wood
    throughout the channel system. The movement of woody debris suggests
    a system that is the reverse of most sediment transport systems in
    mountains. In 1st and 2nd order tributaries, the wood is too large
    to be moved and the system is transport-limited, with floods introducing
    new material through undercutting, but not removing wood through
    downstream transport. In the intermediate 3rd and 4th order channels,
    the system displays characteristics of dynamic equilibrium, where
    the channel is able remove the debris at approximately the same rate
    that it is introduced. The spatial distribution and quantity of wood
    in 3rd and 4th order reaches varies widely, however, as wood is alternatively
    stranded on gravel bars or moved downstream during periods of bar
    mobilization. In the 6th order and larger channels, the system becomes
    supply-limited, where almost all material in the main stream can
    be transported out of the central channel by normal stream flows
    and deposition occurs primarily on banks or in eddy pool environments.
    Attempts to map woody debris with 1-m resolution digital four-band
    imagery were generally unsuccessful, primarily because the imagery
    could not distinguish the narrow logs within a pixel from the surrounding
    sand and gravel background and due to problems in precisely coregistering
    imagery and field maps. (C) 2002 Elsevier Science B.V. All rights
    reserved.
    BibTeX:
    @article{Marcus2002,
      author = {Marcus, WA and Marston, RA and Colvard, CR and Gray, RD},
      title = {Mapping the spatial and temporal distributions of woody debris in streams of the Greater Yellowstone Ecosystem, USA},
      journal = {Geomorphology},
      year = {2002},
      volume = {44},
      number = {3-4},
      pages = {323--335}
    }
    					
    Marcus2002a Marcus, W.A. Mapping of stream microhabitats with high spatial resolution hyperspectral imagery 2002 Journal of Geographical Systems
    Vol. 4 , pp. 113-126  
    article remote sensing
    BibTeX:
    @article{Marcus2002a,
      author = {Marcus, WA},
      title = {Mapping of stream microhabitats with high spatial resolution hyperspectral imagery},
      journal = {Journal of Geographical Systems},
      year = {2002},
      volume = {4},
      pages = {113-126}
    }
    					
    Shuman2002 Shuman, B.; Bartlein, P.; Logar, N.; Newby, P. & Webb, T. Parallel climate and vegetation responses to the early Holocene collapse of the Laurentide Ice Sheet 2002 Quaternary Science Reviews
    Vol. 21 (16-17) , pp. 1793-1805  
    article paleoclimatic analysis and data-model comparisons
    Abstract: Parallel changes in lake-level and pollen data show that the rapid
    decline of the Laurentide Ice Sheet (LIS) between 10,000 and 8000
    cal yr BP triggered a step-like change in North American climates:
    from an ice-sheet-and-insolation-dominated climate to a climate primarily
    controlled by insolation. Maps of the lake-level data from across
    eastern North America, show a reorganization of climate patterns
    that the pollen data independently match. Raised lake-levels and
    expanded populations of moist-tolerant southern pines (Pinus) document
    that summer monsoons intensified in the southeastern United States
    between 9000 and 8000 cal yr BP. Simultaneously, low lake-levels
    and an eastward expansion of the prairie illustrate an increase in
    mid-continental aridity. After the Hudson Bay ice dome collapsed
    around 8200 cal yr BP, lake-levels rose in New England, as populations
    of mesic plant taxa, such as beech (Fagus) and hemlock (Tsuga), replaced
    those of dry-tolerant northern pines (Pinus). Available moisture
    increased there after a related century-scale period of colder-than-previous
    conditions around 8200 cal yr BP, which is also recorded in the pollen
    data. The comparison between pollen and lake-level data confirms
    that vegetations dynamics reflect climatic patterns on the millennial-scale.
    (C) 2002 Elsevier Science Ltd. All rights reserved.
    BibTeX:
    @article{Shuman2002,
      author = {Shuman, B and Bartlein, P and Logar, N and Newby, P and Webb, T},
      title = {Parallel climate and vegetation responses to the early Holocene collapse of the Laurentide Ice Sheet},
      journal = {Quaternary Science Reviews},
      year = {2002},
      volume = {21},
      number = {16-17},
      pages = {1793--1805},
      note = {http://geography.uoregon.edu/envchange/figures/Shuman-etal-QSR-2002b-figs/}
    }
    					
    Shuman2002a Shuman, B.; Thompson, W.; Bartlein, P. & Williams, J.W. The anatomy of a climatic oscillation: vegetation change in eastern North America during the Younger Dryas chronozone 2002 Quaternary Science Reviews
    Vol. 21 (16-17) , pp. 1777-1791  
    article paleoclimatic analysis and data-model comparisons
    Abstract: Century-scale climate changes reshaped circulation patterns over the
    North Atlantic and adjacent regions during the last glacial-to-interglacial
    transition. Here, we show that vegetation across eastern North America
    shifted dramatically at the beginning and end of the Younger Dryas
    chronozone (YDC: 12,900-11,600 cal yr B.P.), when changes in ocean
    circulation rapidly cooled and then warmed the North Atlantic sea-surface.
    On both the site-specific scale and the continental-scale, vegetation
    changed only gradually during the millennia before (15,000-13,000
    cal yr B.P.) and after (11,000-9000 cal yr B.P.) the YDC, but climate
    changes ca 12,900 and 11,600 cal yr B.P. altered the vegetation on
    both spatial scales within centuries. Plant associations changed
    and some taxa rapidly migrated hundreds of kilometers (>300km within
    similar to100yr). In limited regions near the North Atlantic coast,
    abrupt cooling ca 12,900 cal yr B.P. resulted in a return to earlier
    vegetation types. Elsewhere, however, the vegetation patterns during
    the YDC were distinct from those of both earlier and later intervals.
    They indicate abrupt, 'non-reversing' seasonal temperature changes
    that were probably related to atmospheric circulation changes during
    the YDC, rather than to the direct influence of North Atlantic sea-surface
    temperatures. Atmospheric circulation patterns during the YDC were
    unique within the last 21,000yr because of a unique combination of
    climate controls. Insolation, ice sheet extent, and atmospheric composition
    were significantly different from their full-glacial states, even
    when the North Atlantic returned to near full-glacial conditions.
    The YDC vegetation patterns demonstrate (1) rapid ecological responsiveness
    to abrupt climate change and (2) spatially varied patterns of YDC
    climate change. (C) 2002 Elsevier Science Ltd. All rights reserved.
    BibTeX:
    @article{Shuman2002a,
      author = {Shuman, B and Thompson, W and Bartlein, P and Williams, JW},
      title = {The anatomy of a climatic oscillation: vegetation change in eastern North America during the Younger Dryas chronozone},
      journal = {Quaternary Science Reviews},
      year = {2002},
      volume = {21},
      number = {16-17},
      pages = {1777--1791},
      note = {http://geography.uoregon.edu/envchange/figures/Shuman-etal-QSR-2002a-figs/index.html}
    }
    					
    Edwards2001 Edwards, M.E.; Mock, C.J.; Finney, B.P.; Barber, V.A. & Bartlein, P.J. Potential analogues for paleoclimatic variations in eastern interior Alaska during the past 14,000 yr: atmospheric-circulation controls of regional temperature and moisture responses 2001 Quaternary Science Reviews
    Vol. 20 (1-3) , pp. 189-202  
    article modern climate analogues
    Abstract: The paleoclimatic history of a region can be viewed as a series of
    surface temperature and moisture anomalies through time. The effects
    of changes in large-scale climatic controls (e.g., insolation, major
    circulation controls) can be mediated by the influence of smaller-scale
    controls (e.g., topographic barriers, coastlines); this may result
    in heterogenous surface climatic responses at the regional and sub-regional
    scale. Divergent paleoclimatic trajectories between regions may be
    explainable in terms of such meso-scale patterns. Using modern analogues
    for paleoclimate we examine how the sequence of climatic variations
    in eastern interior Alaska during the interval 12,000-0 C-14 yr BP
    could have been generated by specific atmospheric circulation patterns.
    Fossil-pollen and lake-level records document the long-term trends
    in temperature and effective moisture for the region. Water-balance
    modelling provides additional estimates of paleoprecipitation. Synoptic
    climatological patterns are described using the modern (instrumental)
    record of upper-level and sea-level pressure, surface temperature,
    and precipitation. At 12,000 C-14 yr BP, eastern interior Alaska
    was cooler and drier than present, a situation generated today by
    a southward displacement of the jet stream. Conditions warmer and
    drier than present at 9000 C-14 yr BP may have been generated by
    increased ridging north of Alaska and a weakened westerly circulation.
    Warmer, wetter conditions than present possibly prevailed in the
    late-middle Holocene; these might reflect ridging over Alaska and
    troughing further west. Cool, wet conditions feature enhanced westerly
    flow into Alaska through an eastward shift in the east Asian trough
    and positive pressure anomalies in the North Pacific; they may be
    analogous to cold periods of the Little Ice Age. The analogues demonstrate
    how surface conditions in other parts of Beringia may sometimes be
    similar to, while at other times different from those in the eastern
    interior. These broader spatial patterns provide hypotheses about
    past climates that can be tested with paleoclimatological data. For
    example, the widespread positive temperature anomalies associated
    with the warm/dry (9000 C-14 yr BP) analogue fit with the expansion
    northward of the eastern Siberian treeline. The anomalously cool
    conditions in northeast Siberia associated with the warm/wet analogue
    may explain the continued (late-middle Holocene) treeline advance
    in Alaska while there was retreat in Siberia. (C) 2000 Elsevier Science
    Ltd. All rights reserved.
    BibTeX:
    @article{Edwards2001,
      author = {Edwards, ME and Mock, CJ and Finney, BP and Barber, VA and Bartlein, PJ},
      title = {Potential analogues for paleoclimatic variations in eastern interior Alaska during the past 14,000 yr: atmospheric-circulation controls of regional temperature and moisture responses},
      journal = {Quaternary Science Reviews},
      year = {2001},
      volume = {20},
      number = {1-3},
      pages = {189--202},
      note = {http://geography.uoregon.edu/envchange/figures/Edwards-etal-QSR-2001-figs/index.html}
    }
    					
    Gavin2001 Gavin, D.G. Estimation of inbuilt age in radiocarbon ages of soil charcoal for fire history studies 2001 Radiocarbon
    Vol. 43 (1) , pp. 27-44  
    article
    Abstract: Radiocarbon age determinations of wood charcoal are commonly used
    to date past forest fire events, even though such ages should be
    greater than the fire event due to the age of the wood at the time
    of burning. The difference in the C-14-derived age of charcoal and
    the time-since-fire (the "inbuilt age") may be considerable in some
    vegetation types and thus must be estimated before interpreting fire
    dates. Two methods were used to estimate the potential range of inbuilt
    age of soil charcoal dated to determine ages of forest fires on the
    west coast of Vancouver Island (Canada). First, 26 C-14 ages on charcoal
    in surficial soil were compared directly with ages of forest fire
    determined by tree-ring counts, suggesting inbuilt ages of 0-670
    years. Second, a simulation model that uses estimated fuel loads,
    fuel consumption, charcoal production, and the ages of charred wood
    (time since wood formation), suggests that the combination of slow
    growth rates and slow decay rates of certain species can account
    for inbuilt ages of more than 400 years in this forest type. This
    level of inbuilt age is large enough such that the actual age of
    a fire may not occur within the 2 sigma confidence interval of a
    calibrated charcoal C-14 age determination, and thus significantly
    affect the interpretation of fire dates. A method is presented to
    combine the error of a calibrated C-14 age determination with the
    error due to inbuilt age such that the larger adjusted error encompasses
    the actual age of the fire.
    BibTeX:
    @article{Gavin2001,
      author = {Gavin, DG},
      title = {Estimation of inbuilt age in radiocarbon ages of soil charcoal for fire history studies},
      journal = {Radiocarbon},
      year = {2001},
      volume = {43},
      number = {1},
      pages = {27--44}
    }
    					
    Gavin2001a Gavin, D.G.; McLachlan, J.S.; Brubaker, L.B. & Young, K.A. Postglacial history of subalpine forests, Olympic Peninsula, Washington, USA 2001 Holocene
    Vol. 11 (2) , pp. 177-188  
    article
    Abstract: To investigate subalpine vegetation history on the Olympic Peninsula,
    Washington (USA), two pollen, macrofossil and charcoal records were
    studied in climatically distinct zones: Martins Lake (1415 m) in
    the moist Tsuga mertensiana zone and Moose Lake (1508 m) in the drier
    Abies lasiocarpa zone. The interpretation of fossil pollen assemblages
    was aided by comparisons with 308 modern assemblages from the Olympic
    Peninsula and western North America. Both pollen records show a cold/dry
    period following deglaciation (>10000 radiocarbon years BP) with
    sparse tundra and little similarity to any modern pollen assemblage.
    In the early Holocene, when summer temperatures are thought to have
    been higher than present, high percentages of Alnus sinuata-type
    pollen at both lakes suggest increased avalanche activity. At Martins
    Lake warmer summers were not accompanied by forest establishment,
    possibly because persistent spring snow pack, snow avalanches, and/or
    edaphic constraints limited tree establishment at this site. The
    Martins Lake record shows a steplike shift in vegetation to modern
    Tsuga mertensiana/Abies amabilis parkland across the Mazama tephra
    (6730 BP). In contrast to Martins Lake, Abies lasiocarpa forest quickly
    established at Moose Lake in the early Holocene, though forests were
    probably initially open and fires may have been frequent. From 7800
    to 5100 BP forests near Moose Lake shifted gradually to cooler and
    moister species composition, with the addition of Chamaecyparis nootkatensis,
    Tsuga mertensiana and Pinus, though Abies lasiocarpa remained dominant.
    Forest cover was probably greatest during this transition, with parklike
    conditions at Moose Lake beginning at c. 5100 BP. The major differences
    in the records between the two sites may be due to differences in
    the local expression of regional climatic change and/or differences
    in soil development and stabilization.
    BibTeX:
    @article{Gavin2001a,
      author = {Gavin, DG and McLachlan, JS and Brubaker, LB and Young, KA},
      title = {Postglacial history of subalpine forests, Olympic Peninsula, Washington, USA},
      journal = {Holocene},
      year = {2001},
      volume = {11},
      number = {2},
      pages = {177--188}
    }
    					
    Gritzner2001 Gritzner, M.L.; Marcus, W.A.; Aspinall, R. & Custer, S.G. Assessing landslide potential using GIS, soil wetness modeling and topographic attributes, Payette River, Idaho 2001 Geomorphology
    Vol. 37 (1-2) , pp. 149-165  
    article
    Abstract: This study utilizes GIS modeling to determine if the location of 559
    landslides in the 875 km(2) catchment of the Middle Fork of the Payette
    River, Idaho can be predicted based on topographic attributes and
    a wetness index generated by the DYNWET model. Slope and elevation
    were significantly related to landslide occurrence at this landscape
    scale. Aspect was also retained as a variable for further analysis
    because, despite a non-significant chi-square relation to landslide
    occurrence, graphical analysis suggested a relation between aspect
    and mass wasting. Chi-square analysis indicated that plan and profile
    curvature, flow path length, upslope contributing area. and the DYNWET-based
    moisture index were not significantly related to landsliding. A Bayesian
    probability model based on combinations of elevation, slope, aspect,
    and wetness indicates that elevation exhibits the closest relation
    to landsliding. followed by slope; but that neither aspect nor wetness
    index values help in prediction. The Bayesian probability model using
    elevation and slope generates a map of relative landslide risk that
    can be used to direct activities away from mass wasting prone areas,
    The association between elevation and landslides is perplexing but
    is perhaps due to the location of logging road at specific elevations
    (roads could not be included in the input data for analysis because
    they have not been adequately mapped). The lack of explanation provided
    by the DYNWET wetness index was also surprising and may be due to
    the 30-m digital elevation model (DEM) and the soils data having
    resolutions too coarse to adequately portray local variations key
    to mass wasting. We believe the inadequacy of data to drive the models
    is typical of the majority of catchment scale setting. For now, the
    ability of researchers to effectively model landscape scale landsliding
    is more limited by the type, resolution, and quality of available
    data than by the quality of the landslide models. (C) 2001 Elsevier
    Science B.V. All rights reserved.
    BibTeX:
    @article{Gritzner2001,
      author = {Gritzner, ML and Marcus, WA and Aspinall, R and Custer, SG},
      title = {Assessing landslide potential using GIS, soil wetness modeling and topographic attributes, Payette River, Idaho},
      journal = {Geomorphology},
      year = {2001},
      volume = {37},
      number = {1-2},
      pages = {149--165}
    }
    					
    Hansen2001 Hansen, A.J.; Neilson, R.R.; Dale, V.H.; Flather, C.H.; Iverson, L.R.; Currie, D.J.; Shafer, S.; Cook, R. & Bartlein, P.J. Global change in forests: Responses of species, communities, and biomes 2001 Bioscience
    Vol. 51 (9) , pp. 765-779  
    article future vegetation changes
    BibTeX:
    @article{Hansen2001,
      author = {Hansen, AJ and Neilson, RR and Dale, VH and Flather, CH and Iverson, LR and Currie, DJ and Shafer, S and Cook, R and Bartlein, PJ},
      title = {Global change in forests: Responses of species, communities, and biomes},
      journal = {Bioscience},
      year = {2001},
      volume = {51},
      number = {9},
      pages = {765--779}
    }
    					
    Marcus2001 Marcus, W.A.; Meyer, G.A. & Nimmo, D.R. Geomorphic control of persistent mine impacts in a Yellowstone Park stream and implications for the recovery of fluvial systems 2001 Geology
    Vol. 29 (4) , pp. 355-358  
    article
    Abstract: A half-century after mine closure, metal contamination from sulfide
    ore mining in the headwaters continues to impair riparian vegetation
    and aquatic macroinvertebrates along Soda Butte Creek, Yellowstone
    National Park. A tailings dam failure in 1950 emplaced metal-rich
    sediment at high flood-plain levels, above 50 yr to 100 yr flood
    stages in 1996 and 1997. These large natural floods removed only
    a small part of the contaminated sediment through bank erosion; they
    also failed to lower in-channel Cu concentrations, because increased
    erosion of mine waste during high hows balances increased inputs
    of uncontaminated sediments, generating no net change in concentrations.
    Geomorphic processes controlling movement of contaminated sediments
    indicate that mine impacts will persist for centuries in Soda Butte
    Creek and imply long-lasting impacts in similarly affected streams
    worldwide.
    BibTeX:
    @article{Marcus2001,
      author = {Marcus, WA and Meyer, GA and Nimmo, DR},
      title = {Geomorphic control of persistent mine impacts in a Yellowstone Park stream and implications for the recovery of fluvial systems},
      journal = {Geology},
      year = {2001},
      volume = {29},
      number = {4},
      pages = {355--358}
    }
    					
    Mcdowell2001 McDowell, P.F. Dorava, J. & others (Hrsg.) Spatial variation of channel morphology at the segment and reach scales, Middle Fork of the John Day River, northeastern Oregon ( Geomorphic Processes and Riverine Habitat ) 2001 Geomorphic Processes and Riverine Habitat
    Vol. 4 , pp. 159-172  
    inbook fluvial geomorphology
    BibTeX:
    @inbook{Mcdowell2001,
      author = {McDowell, PF},
      title = {Geomorphic Processes and Riverine Habitat},
      publisher = {American Geophysical Union},
      year = {2001},
      volume = {4},
      pages = {159-172}
    }
    					
    McDowell2001 McDowell, P.F. & Edwards, M.E. Evidence of Quaternary climatic variations in a sequence of loess and related deposits at Birch Creek, Alaska: implications for the Stage 5 climatic chronology 2001 Quaternary Science Reviews
    Vol. 20 (1-3) , pp. 63-76  
    article paleoecology and paleoclimatology
    Abstract: A 45 m outcrop of Quaternary sediments on Birch Creek, near Circle,
    Alaska, reveals a record of fluctuating environmental conditions
    that probably spans several glacial-interglacial cycles. From base
    to top the deposits are forested floodplain (warm), colluvium with
    ice wedges (cold), forest soil (warm)? loess (cold), paleosol containing
    Old Crow Tephra (OCt) (cool-to-warm), loess (cold), lacustrine (very
    warm), loess (cold), and modern forest soil (warm). Resolution of
    the paleoclimatic history associated with the OCt event is critical
    to understanding the nature of stage 5 in the western North American
    Arctic. Application of recent age estimates for the OCt tephra (ca.
    140,000 yr BP) to the Birch Creek section would indicate that either
    (i) the tephra/paleosol dates from the 6/5.5 transition, a strongly
    developed glacial interval occurred within stage 5, and the overlying
    very warm interval occurred in 5.3 or 5.1, or (ii) the tephra was
    deposited during a "non-Milankovitch" warming event late in stage
    6. A paleoclimate chronology provides an alternative interpretation,
    (iii), in which the tephra/paleosol corresponds to stage 6 or even
    stage 7, the overlying loess to stage 6, and the lake sediments to
    all or part of stage 5, but the OCt is older than 140,000 yr BP.
    Chronologies (ii) and (iii) imply a very warm beginning to stage
    5, consistent with paleoclimate model simulations and data from other
    regions. (C) 2000 Elsevier Science Ltd. All rights reserved.
    BibTeX:
    @article{McDowell2001,
      author = {McDowell, PF and Edwards, ME},
      title = {Evidence of Quaternary climatic variations in a sequence of loess and related deposits at Birch Creek, Alaska: implications for the Stage 5 climatic chronology},
      journal = {Quaternary Science Reviews},
      year = {2001},
      volume = {20},
      number = {1-3},
      pages = {63--76}
    }
    					
    Shafer2001 Shafer, S.L.; Bartlein, P.J. & Thompson, R.S. Potential changes in the distributions of western North America tree and shrub taxa under future climate scenarios 2001 Ecosystems
    Vol. 4 (3) , pp. 200-215  
    article future vegetation changes
    Abstract: Increases in atmospheric greenhouse gases are driving significant
    changes in global climate. To project potential vegetation response
    to future climate change, this study uses response surfaces to describe
    the relationship between bioclimatic variables and the distribution
    of tree and shrub taxa in western North America. The response surfaces
    illustrate the probability of the occurrence of a taxon at particular
    points in climate space. Climate space was defined using three bioclimatic
    variables: mean temperature of the coldest month, growing degree
    days, and a moisture index. Species distributions were simulated
    under present climate using observed data (1951-80, 30-year mean)
    and under future climate (2090-99, 10-year mean) using scenarios
    generated by three general circulation models-HADCM2, CGCM1, and
    CSIRO. The scenarios assume a 1% per year compound increase in greenhouse
    gases and changes in sulfate (SO4) aerosols based on the Intergovernmental
    Panel on Climate Change (IPCC) IS92a scenario. The results indicate
    that under future climate conditions, potential range changes could
    be large for many tree and shrub taxa. Shifts in the potential ranges
    of species are simulated to occur not only northward but in all directions,
    including southward of the existing ranges of certain species. The
    simulated potential distributions of some species become increasingly
    fragmented under the future climate scenarios, while the simulated
    potential distributions of other species expand. The magnitudes of
    the simulated range changes imply significant impacts to ecosystems
    and shifts in patterns of species diversity in western North America.
    BibTeX:
    @article{Shafer2001,
      author = {Shafer, SL and Bartlein, PJ and Thompson, RS},
      title = {Potential changes in the distributions of western North America tree and shrub taxa under future climate scenarios},
      journal = {Ecosystems},
      year = {2001},
      volume = {4},
      number = {3},
      pages = {200--215}
    }
    					
    Whitlock2001 Whitlock, C.; Bartlein, P.J.; Markgraf, V. & Ashworth, A.C. Markgraf, V. (Hrsg.) The Mid-latitudes of North and South America During the Last Glacial Maximum and Early Holocene: Similar Paleoclimatic Sequences Despite Differing Large-Scale Controls ( Interhemispheric Climate Linkages in the Americas and their Societal Effects ) 2001 Interhemispheric Climate Linkages in the Americas and their Societal Effects , pp. 391-416   inbook paleoclimatic analysis and data-model comparisons
    BibTeX:
    @inbook{Whitlock2001,
      author = {Whitlock, C and Bartlein, PJ and Markgraf, V and Ashworth, AC},
      title = {Interhemispheric Climate Linkages in the Americas and their Societal Effects},
      publisher = {Academic Press},
      year = {2001},
      pages = {391-416},
      note = {http://geography.uoregon.edu/envchange/figures/Whitlock-etal-IHCL-2001-figs/index.html}
    }
    					
    Hostetler2000 Hostetler, S.W.; Bartlein, P.J.; Clark, P.U.; Small, E.E. & Solomon, A.M. Simulated influences of Lake Agassiz on the climate of central North America 11,000 years ago 2000 Nature
    Vol. 405 (6784) , pp. 334-337  
    article paleoclimatology
    Abstract: Eleven thousand years ago, large lakes existed in central and eastern
    North America along the margin of the Laurentide Ice Sheet. The large-scale
    North American climate at this time has been simulated with atmospheric
    general circulation models(1,2), but these relatively coarse global
    models do not resolve potentially important features of the mesoscale
    circulation that arise from interactions among the atmosphere, ice
    sheet, and proglacial lakes. Here we present simulations of the climate
    of central and eastern North America 11,000 years ago with a high-resolution,
    regional climate model nested within a general circulation model.
    The simulated climate is in general agreement with that inferred
    from palaeoecological evidence. Our experiments indicate that through
    mesoscale atmospheric feedbacks, the annual delivery of moisture
    to the Laurentide Ice Sheet was diminished at times of a large, cold
    Lake Agassiz relative to periods of lower lake stands. The resulting
    changes in the mass balance of the ice sheet may have contributed
    to fluctuations of the ice margin, thus affecting the routing of
    fresh water to the North Atlantic Ocean. A retreating ice margin
    during periods of high lake level may have opened an outlet for discharge
    of Lake Agassiz into the North Atlantic. A subsequent advance of
    the ice margin due to greater moisture delivery associated with a
    low lake level could have dammed the outlet, thereby reducing discharge
    to the North Atlantic. These variations may have been decisive in
    causing the Younger Dryas cold event(3,4).
    BibTeX:
    @article{Hostetler2000,
      author = {Hostetler, SW and Bartlein, PJ and Clark, PU and Small, EE and Solomon, AM},
      title = {Simulated influences of Lake Agassiz on the climate of central North America 11,000 years ago},
      journal = {Nature},
      year = {2000},
      volume = {405},
      number = {6784},
      pages = {334--337},
      note = {http://geography.uoregon.edu/envchange/figures/Hostetler-etal-Nature-2000-figs/index.html}
    }
    					
    McDowell2000 McDowell, P.F. American Water Resources Association Human impacts and river channel adjustment, northeastern Oregon: implications for restoration 2000 Riparian Ecology and Management in Multi-Land Use Watersheds Symposium Proceedings, Annual International Summer Specialty Conference, August 27-30, 2000   inproceedings fluvial geomorphology
    BibTeX:
    @inproceedings{McDowell2000,
      author = {McDowell, PF},
      title = {Human impacts and river channel adjustment, northeastern Oregon: implications for restoration},
      booktitle = {Riparian Ecology and Management in Multi-Land Use Watersheds Symposium Proceedings, Annual International Summer Specialty Conference, August 27-30, 2000},
      year = {2000}
    }
    					
    Millspaugh2000 Millspaugh, S.H.; Whitlock, C. & Bartlein, P.J. Variations in fire frequency and climate over the past 17 000 yr in central Yellowstone National Park 2000 Geology
    Vol. 28 (3) , pp. 211-214  
    article
    Abstract: A 17000 yr fire history from Yellowstone National Park demonstrates
    a strong link between changes in climate and variations in fire frequency
    on millennial time scales. The the history reconstruction is based
    on a detailed charcoal stratigraphy from Cygnet Lake in the rhyolite
    plateau region. Macroscopic charcoal particles were tallied from
    contiguous 1 cm samples of a 6.69-m-long core, and the data were
    converted to charcoal-accumulation rates at evenly spaced time intervals.
    Intervals of high charcoal-accumulation rates were interpreted as
    local fire events on the basis of information obtained from modern
    charcoal-calibration studies in the Yellowstone region. The record
    indicates that fire frequency was moderate (4 fires/1000 yr) during
    the late glacial period, reached highest values in the early Holocene
    (>10 tires/1000 yr), and decreased after 7000 calendar Sr B.P. The
    present fire regime (2-3 fires/1000 yr) was established in the past
    2000 Sr The charcoal stratigraphy correlates well with variations
    in July insolation through time, which suggests that regional climate
    changes are responsible for the long-term variations in fire frequency.
    In the early Holocene, summer insolation was near its maximum, which
    resulted in warmer, effectively drier conditions throughout the northwestern
    United States. At this time, the fire frequency near Cygnet Lake
    was at its highest. After 7000 calendar ST B.P., summer insolation
    decreased to present values, the regional climate became cooler and
    wetter, and fires were less frequent. The Cygnet Lake record suggests
    that long-term fire frequencies have varied continuously with climate
    change, even when the vegetation has remained constant.
    BibTeX:
    @article{Millspaugh2000,
      author = {Millspaugh, SH and Whitlock, C and Bartlein, PJ},
      title = {Variations in fire frequency and climate over the past 17 000 yr in central Yellowstone National Park},
      journal = {Geology},
      year = {2000},
      volume = {28},
      number = {3},
      pages = {211--214},
      note = {http://geography.uoregon.edu/envchange/figures/Millspaugh-etal-Geology-2000-figs/index.html}
    }
    					
    Mock2000 Mock, C.J. Rainfall in the Garden of the United States Great Plains; 1870-1889 2000 Climatic Change
    Vol. 44 , pp. 173-195  
    article human dimensions of climate change
    BibTeX:
    @article{Mock2000,
      author = {Mock, CJ},
      title = {Rainfall in the Garden of the United States Great Plains; 1870-1889},
      journal = {Climatic Change},
      year = {2000},
      volume = {44},
      pages = {173-195}
    }
    					
    Stoughton2000 Stoughton, J.A. & Marcus, W.A. Persistent impacts of trace metals from mining on floodplain grass communities along Soda Butte Creek, Yellowstone National Park 2000 Environmental Management
    Vol. 25 (3) , pp. 305-320  
    article
    Abstract: In Yellowstone National Park, tailings and associated trace metals
    from past mining have been deposited along 28 km of Soda Butte Creek
    by large flood events. This study documents grass species diversity,
    density, and biomass; trace metal concentrations in soils; and soil
    pH, salinity, and clay content in four selected floodplain meadows
    contaminated by these tailings. Trace metal levels frequently exceed
    acceptable concentrations for agricultural soils at sampling points
    within the meadows. pH levels within flood-deposited tailings are
    strongly to moderately acid, while pH levels outside of tailings
    deposits are neutral. The data analysis: (1) shows that metals and
    acidity associated with tailings affect plant biomass, density, and
    diversity; (2) documents that the vegetation/metal and vegetation/pH
    associations are more of a threshold than a linear relationship;
    and (3) suggests that other factors may be involved in structuring
    the community. Vegetation diversity, density, and biomass decrease
    at threshold levels of trace metal concentrations and soil pH in
    all four meadows. CuSum plots of diversity in relation to trace metal
    levels show a decrease in mean diversity at 315 ppm copper, 22 ppm
    arsenic, 4.2% iron, 65 ppm lead, and 170 ppm zinc. Densities of Phleum
    pratense and Poa pratensis were significantly lower(P less than or
    equal to 0.001) on plots with more than 250 ppm copper. Above-ground
    biomass of Phleum pratense was also significantly lower on plots
    with copper levels above 250 ppm. Decreased mean grass density was
    found on plots with pH < 6.4, but the only statistically significant
    difference was for Juncus balticus, which had increased density on
    plots with pH < 6.4. In contrast to the clear impacts of trace metals
    and pl-l on vegetation, other site characteristics did not alter
    measured vegetation characteristics.
    BibTeX:
    @article{Stoughton2000,
      author = {Stoughton, JA and Marcus, WA},
      title = {Persistent impacts of trace metals from mining on floodplain grass communities along Soda Butte Creek, Yellowstone National Park},
      journal = {Environmental Management},
      year = {2000},
      volume = {25},
      number = {3},
      pages = {305--320}
    }
    					
    Whitlock2000 Whitlock, C.; Sarna-Wojcicki, A.M.; Bartlein, P.J. & Nickmann, R.J. Environmental history and tephrostratigraphy at Carp Lake, southwestern Columbia Basin, Washington, USA 2000 Palaeogeography Palaeoclimatology Palaeoecology
    Vol. 155 (1-2) , pp. 7-29  
    article paleoclimatology and paleoecology
    Abstract: Sediment cores from Carp Lake provide a pollen record of the last
    ca. 125,000 years that helps disclose vegetational and climatic conditions
    from the present day to the previous interglaciation (120-133 ka).
    The core also contained 15 tephra layers, which were characterised
    by electron-microprobe analysis of volcanic glass shards. Identified
    tephra include Mount St. Helens Ye, 3.69 ka; Mazama ash bed, 7.54
    ka; Mount St, Helens layer C, 35-50 ka; an unnamed Mount St. Helens
    tephra, 75-150 ka; the tephra equivalent of layer E at Pringle Falls,
    Oregon, <218 ka; and an andesitic tephra layer similar to that at
    Tulelake, California, 174 ka, Ten calibrated radiocarbon ages and
    the ages of Mount St. Helens Ye, Mazama ash, and the unnamed Mount
    St, Helens tephra were used to develop an age-depth model. This model
    was refined by also incorporating the age of marine oxygen isotope
    stage (IS) boundary 4/5 (73.9 ka) and the age of IS-Se (125 ka).
    The justification for this age-model is based on an analysis of the
    pollen record and lithologic data. The pollen record is divided into
    11 assemblage zones that describe alternations between periods of
    montane conifer forest, pine forest, and steppe. The previous interglacial
    period (IS-5e) supported temperate xerothermic forests of pine and
    oak and a northward and westward expansion of steppe and juniper
    woodland, compared to their present occurrence. The period from 83
    to 117 ka contains intervals of pine forest and parkland alternating
    with pine-spruce forest, suggesting shifts from cold humid to cool
    temperate conditions. Between 73 and 83 ka, a forest of oak, hemlock,
    Douglas-fir, and fir was present that has no modem analogue. It suggests
    warm wet summers and cool wet winters. Cool humid conditions during
    the mid-Wisconsin interval supported mixed conifer forest with Douglas-fir
    and spruce. The glacial interval featured cold dry steppe, with an
    expansion of spruce in the late-glacial. Xerothermic communities
    prevailed in the early Holocene, when temperate steppe was widespread
    and the lake dried intermittently. The middle Holocene was characterised
    by ponderosa pine forest, and the modern vegetation was established
    in the last 3900 yr, when ponderosa pine, Douglas-fir, fir, and oak
    were part of the local vegetation. (C) 2000 Elsevier Science B.V.
    All rights reserved.
    BibTeX:
    @article{Whitlock2000,
      author = {Whitlock, C and Sarna-Wojcicki, AM and Bartlein, PJ and Nickmann, RJ},
      title = {Environmental history and tephrostratigraphy at Carp Lake, southwestern Columbia Basin, Washington, USA},
      journal = {Palaeogeography Palaeoclimatology Palaeoecology},
      year = {2000},
      volume = {155},
      number = {1-2},
      pages = {7--29},
      note = {http://geography.uoregon.edu/envchange/figures/Whitlock-etal-P3-2000-figs/index.html}
    }
    					
    Williams2000 Williams, J.W.; Webb, T.; Shurman, B.N. & Bartlein, P.J. Do low CO2 concentrations affect pollen-based reconstructions of LGM climates? A response to "Physiological significance of low atmospheric CO2 for plant-climate interactions" by Cowling and Sykes 2000 Quaternary Research
    Vol. 53 (3) , pp. 402-404  
    article vegetation and climate
    BibTeX:
    @article{Williams2000,
      author = {Williams, JW and Webb, T and Shurman, BN and Bartlein, PJ},
      title = {Do low CO2 concentrations affect pollen-based reconstructions of LGM climates? A response to "Physiological significance of low atmospheric CO2 for plant-climate interactions" by Cowling and Sykes},
      journal = {Quaternary Research},
      year = {2000},
      volume = {53},
      number = {3},
      pages = {402--404}
    }
    					
    Wright2000 Wright, A.; Marcus, W.A. & Aspinall, R. Evaluation of multispectral, fine scale digital imagery as a tool for mapping stream morphology 2000 Geomorphology
    Vol. 33 (1-2) , pp. 107-120  
    article
    Abstract: Multispectral digital imagery acquired from Soda Butte and Cache Creeks,
    Montana and Wyoming was used in conjunction with field data to classify
    and map hydrogeomorphic stream units on four stream reaches. The
    morphologic units that were field mapped were eddy drop zones, glides,
    low gradient riffles, high gradient riffles, lateral scour pools,
    attached bars, detached bars, and large woody debris. Unsupervised
    and supervised classifications of the imagery were used to develop
    a Maximum Joint Probability classification and an Alternative Joint
    Probability classification of the stream reaches. The Maximum Joint
    Probability classification allowed only one of the image classes
    to represent each hydrogeomorphic unit on the field map and resulted
    in relatively low overall accuracies for identification of these
    units of 10% to 50%. The Alternative Joint Probability classification
    allowed each image class to represent any geomorphic unit where the
    probability of a correct classification was greater than random.
    In this technique, two or three image classes were assigned to represent
    each hydrogeomorphic unit, resulting in higher overall accuracies
    of 28% to 80%. Accurate classification of hydrogeomorphic units was
    hampered by poor rectification of imagery with the field maps because
    of inadequate ground control points. In general, the largest hydrogeomorphic
    units were most accurately classified, whereas units that were small
    in area or spatially linear were least likely to be accurately classified.
    The results of this study demonstrated that multispectral digital
    imagery has the potential to be a useful tool for mapping hydrogeomorphic
    stream units at fine scales. Imagery to be an effective tool, however,
    careful measures such as accurate documentation of ground control
    points must be taken to ensure accurate rectification of the imagery
    with field maps. (C) 2000 Elsevier Science B.V. All rights reserved.
    BibTeX:
    @article{Wright2000,
      author = {Wright, A and Marcus, WA and Aspinall, R},
      title = {Evaluation of multispectral, fine scale digital imagery as a tool for mapping stream morphology},
      journal = {Geomorphology},
      year = {2000},
      volume = {33},
      number = {1-2},
      pages = {107--120}
    }
    					
    Farrera1999 Farrera, I.; Harrison, S.P.; Prentice, I.C.; Ramstein, G.; Guiot, J.; Bartlein, P.J.; Bonnefille, R.; Bush, M.; Cramer, W.; von Grafenstein, U.; Holmgren, K.; Hooghiemstra, H.; Hope, G.; Jolly, D.; Lauritzen, S.E.; Ono, Y.; Pinot, S.; Stute, M. & Yu, G. Tropical climates at the Last Glacial Maximum: a new synthesis of terrestrial palaeoclimate data. I. Vegetation, lake levels and geochemistry 1999 Climate Dynamics
    Vol. 15 (11) , pp. 823-856  
    article
    Abstract: Palaeodata in synthesis form are needed as benchmarks for the Palaeoclimate
    Modelling Intercomparison Project (PMIP), Advances since the last
    synthesis of terrestrial palaeodata from the last glacial maximum
    (LGM) call for a new evaluation, especially of data from the tropics.
    Here pollen, plant-macrofossil, lake-level, noble gas (from groundwater)
    and delta(18)O (from speleothems) data are compiled for 18 +/- 2
    ka (C-14), 32 degrees N-33 degrees S. The reliability of the data
    was evaluated using explicit criteria and some types of data were
    re-analysed using consistent methods in order to derive a set of
    mutually consistent palaeoclimate estimates of mean temperature of
    the coldest month (MTCO), mean annual temperature (MAT), plant available
    moisture (PAM) and runoff (P-E). Cold-month temperature (MAT) anomalies
    from plant data range from -1 to -2 K near sea level in Indonesia
    and the S Pacific, through -6 to -8 K at many high-elevation sites
    to -8 to -15K in S China and the SE USA. MAT anomalies from groundwater
    or speleothems seem more uniform (-4 to -6 K), but the data are as
    yet sparse; a clear divergence between MAT and cold-month estimates
    from the same region is seen only in the SE USA, where cold-air advection
    is expected to have enhanced cooling in winter. Regression of all
    cold-month anomalies against site elevation yielded an estimated
    average cooling of - 2.5 to - 3 K at modern sea level, increasing
    to approximate to - 6 K by 3000m. How ever, Neotropical sites showed
    larger than the average sea-level cooling (- 5 to - 6 K) and a non-significant
    elevation effect, whereas W and S Pacific sites showed much less
    sea-level cooling (- 1 K) and a stronger elevation effect. These
    findings support the inference that tropical sea-surface temperatures
    (SSTs) were lower than the CLIMAP estimates, but they limit the plausible
    average tropical sea-surface cooling, and they support the existence
    of CLIMAP-like geographic patterns in SST anomalies. Trends of PAM
    and lake levels indicate wet LGM conditions in the W USA, and at
    the highest elevations, with generally dry conditions elsewhere.
    These results suggest a colder-than-present ocean surface producing
    a weaker hydrological cycle, more arid continents, and arguably steeper-than-present
    terrestrial lapse rates. Such linkages are supported by recent observations
    on freezing-level height and tropical SSTs, moreover, simulations
    of "greenhouse" and LGM climates point to several possible feedback
    processes by which low-level temperature anomalies might be amplified
    aloft.
    BibTeX:
    @article{Farrera1999,
      author = {Farrera, I and Harrison, SP and Prentice, IC and Ramstein, G and Guiot, J and Bartlein, PJ and Bonnefille, R and Bush, M and Cramer, W and von Grafenstein, U and Holmgren, K and Hooghiemstra, H and Hope, G and Jolly, D and Lauritzen, SE and Ono, Y and Pinot, S and Stute, M and Yu, G},
      title = {Tropical climates at the Last Glacial Maximum: a new synthesis of terrestrial palaeoclimate data. I. Vegetation, lake levels and geochemistry},
      journal = {Climate Dynamics},
      year = {1999},
      volume = {15},
      number = {11},
      pages = {823--856}
    }
    					
    Gavin1999 Gavin, D.G. & Brubaker, L.B. A 6000-year soil pollen record of subalpine meadow vegetation in the Olympic Mountains, Washington, USA 1999 Journal of Ecology
    Vol. 87 (1) , pp. 106-122  
    article
    Abstract: 1 Subalpine meadow communities are influenced by edaphic and microclimatic
    gradients, and should be affected by climate change that affects
    these local controls. We used pollen preserved in meadow soils to
    investigate the long-term interaction of these factors in a 1-ha
    subalpine meadow in the Olympic Mountains, Washington, USA. 2 To
    describe the spatial scale at which soil pollen is related to neighbouring
    vegetation, pollen in 46 soil surface samples was compared with plant
    cover within concentric circular plots (0.5-1 m radii). Regression
    analysis of percentage pollen with plant cover at different distances
    from the surface sample had the highest correlation with radii <
    1 m, confirming that entomophilous meadow species have very small
    relevant pollen source areas. 3 We analysed pollen records in soil
    columns at three sites representing a range of growing season lengths
    and community types within the meadow. Soils had aggraded by the
    deposition of eolian silt. Radiocarbon dates of pollen concentrates
    were similar to or older than radiocarbon dates on charcoal pieces
    at the same depth, suggesting negligible downwards movement of pollen
    in the soil profile. 4 The oldest soil pollen profile was from the
    wettest microsite, currently dominated by a snowbed Carex nigricans
    community. This site was occupied by a dry Juniperus community prior
    to c. 6000 BP (before present), when it shifted to more mesic communities
    dominated by Poaceae and Polemonium. The first appearance of a snowbed
    Calex nigricans community at this site, c, 2500-1500 BP suggests
    a change to cooler and/or wetter regional climate. 5 High levels
    of Polygonum bistortoides at all sites indicated a shift to long
    snow-free periods and mesic summer conditions during an interval
    corresponding to the Medieval Warm Period (c. 1200-700 BP). After
    500 BP (during the Little Ice Age) Carex nigricans re-established
    in the wet microsite, while relatively little change occurred at
    the other two sites. Overall, the greater magnitude of change at
    this microsite than at the longer growing-season sites indicates
    that, in these subalpine meadows, short growing season sites are
    most sensitive to regional climate change.
    BibTeX:
    @article{Gavin1999,
      author = {Gavin, DG and Brubaker, LB},
      title = {A 6000-year soil pollen record of subalpine meadow vegetation in the Olympic Mountains, Washington, USA},
      journal = {Journal of Ecology},
      year = {1999},
      volume = {87},
      number = {1},
      pages = {106--122}
    }
    					
    Gavin1999a Gavin, D.G. & Peart, D.R. Vegetative life history of a dominant rain forest canopy tree 1999 Biotropica
    Vol. 31 (2) , pp. 288-294  
    article
    Abstract: Tetramerista glabra has a remarkable combination of life history traits.
    it is a dense-wooded, large, common canopy tree in primary pear swamp
    rain forest. Its seedlings, although shade tolerant, can grow rapidly
    in high light conditions, but frequently lack structural stability
    Most juvenile stems (94% in the understory and 38% in canopy gaps)
    collapse under their own weight or from branchfalls. Fallen stems
    then ramify into vegetative sprouts, which in turn may collapse,
    perpetuating a vegetative juvenile cycle. Most recruitment is from
    sprouts rather than from seed. Structural analysis of stem dimensions
    shows that stems 2-8 cm DBH (diameter at breast height) are dose
    to the theoretical buckling limit, especially for those dependent
    on neighboring vegetation to maintain vertical form. Trees > 4 cm
    DBH persisting as upright stems develop stilt root support and become
    structurally independent at ca 8 cm DBH. Eventually, as stems thicken,
    stilt roots anastamose and trees adopt the cylindrical growth form
    of mature canopy trees (up to 150 cm DBH). Thus, the vegetative life
    history strategy of the species is to: (i) regenerate a large "ramet
    bank" from the majority of juveniles that fail structurally while
    suppressed in the understory, and (ii) to maximize height growth
    at the expense of diameter growth in high light conditions. The growth
    pattern and plastic form of I:glabra shows how a shade tolerant species
    may adapt to utilize the ephemeral light resource in canopy gaps.
    The growth strategy of this species allows it to circumvent the normal
    trade-off between shade tolerance and rapid growth in Canopy gaps.
    BibTeX:
    @article{Gavin1999a,
      author = {Gavin, DG and Peart, DR},
      title = {Vegetative life history of a dominant rain forest canopy tree},
      journal = {Biotropica},
      year = {1999},
      volume = {31},
      number = {2},
      pages = {288--294}
    }
    					
    Hostetler1999 Hostetler, S.W.; Clark, P.U.; Bartlein, P.J.; Mix, A.C. & Pisias, N.J. Atmospheric transmission of North Atlantic Heinrich events 1999 Journal of Geophysical Research-Atmospheres
    Vol. 104 (D4) , pp. 3947-3952  
    article paleoclimatic analysis and data-model comparisons
    Abstract: We model the response of the climate system during Heinrich event
    2 (H2) by employing an atmospheric general circulation model, using
    boundary conditions based on the concept of a "canonical" Heinrich
    event. The canonical event is initialized with a full-height Laurentide
    ice sheet (LIS) and CLIMAP sea surface temperatures (SSTs), followed
    by lowering of the LIS, then warming of North Atlantic SSTs. Our
    modeled temperature and wind fields exhibit spatially variable responses
    over the Northern Hemisphere at each stage of the H2 event. In some
    regions the climatic responses are additive, whereas in other regions
    they cancel or are of opposite sign, suggesting that Heinrich event
    climatic variations may have left complex signatures in geologic
    records. We find variations in the tropical water balance and the
    mass balance of ice sheets, and implications for variations in terrestrial
    methane production from the contraction of northern permafrost regions
    and the expansion of tropical wetlands.
    BibTeX:
    @article{Hostetler1999,
      author = {Hostetler, SW and Clark, PU and Bartlein, PJ and Mix, AC and Pisias, NJ},
      title = {Atmospheric transmission of North Atlantic Heinrich events},
      journal = {Journal of Geophysical Research-Atmospheres},
      year = {1999},
      volume = {104},
      number = {D4},
      pages = {3947--3952},
      note = {http://geography.uoregon.edu/envchange/figures/Hostetler-etal-JGR-1999-figs/index.html}
    }
    					
    Hostetler1999a Hostetler, S.W. & Bartlein, P.J. Webb, R.S.; Clark, P.U. & Kaigwin, L.D. (Hrsg.) Simulation of the potential responses of regional climate and surface processes in western North America to a canonical Heinrich event ( Mechanisms of Global Climate Change at Millennial Time Scales ) 1999 Mechanisms of Global Climate Change at Millennial Time Scales , pp. 313-327   inbook
    BibTeX:
    @inbook{Hostetler1999a,
      author = {Hostetler, SW and Bartlein, PJ},
      title = {Mechanisms of Global Climate Change at Millennial Time Scales},
      publisher = {American Geophysical Union},
      year = {1999},
      pages = {313-327}
    }
    					
    Joussaume1999 Joussaume, S.; Taylor, K.E.; Braconnot, P.; Mitchell, J.F.B.; Kutzbach, J.E.; Harrison, S.P.; Prentice, I.C.; Broccoli, A.J.; Abe-Ouchi, A.; Bartlein, P.J.; Bonfils, C.; Dong, B.; Guiot, J.; Herterich, K.; Hewitt, C.D.; Jolly, D.; Kim, J.W.; Kislov, A.; Kitoh, A.; Loutre, M.F.; Masson, V.; McAvaney, B.; McFarlane, N.; de Noblet, N.; Peltier, W.R.; Peterschmitt, J.Y.; Pollard, D.; Rind, D.; Royer, J.F.; Schlesinger, M.E.; Syktus, J.; Thompson, S.; Valdes, P.; Vettoretti, G.; Webb, R.S. & Wyputta, U. Monsoon changes for 6000 years ago: Results of 18 simulations from the Paleoclimate Modeling Intercomparison Project (PMIP) 1999 Geophysical Research Letters
    Vol. 26 (7) , pp. 859-862  
    article paleoclimatology
    Abstract: Amplification of the northern hemisphere seasonal cycle of insolation
    during the mid-Holocene causes a northward shift of the main regions
    of monsoon precipitation over Africa and India in all 18 simulations
    conducted for the Paleoclimate Modeling Intercomparison Project (PMIP).
    Differences among simulations are related to differences in model
    formulation. Despite qualitative agreement with paleoecological estimates
    of biome shifts, the magnitude of the monsoon increases over northern
    Africa are underestimated by all the models.
    BibTeX:
    @article{Joussaume1999,
      author = {Joussaume, S and Taylor, KE and Braconnot, P and Mitchell, JFB and Kutzbach, JE and Harrison, SP and Prentice, IC and Broccoli, AJ and Abe-Ouchi, A and Bartlein, PJ and Bonfils, C and Dong, B and Guiot, J and Herterich, K and Hewitt, CD and Jolly, D and Kim, JW and Kislov, A and Kitoh, A and Loutre, MF and Masson, V and McAvaney, B and McFarlane, N and de Noblet, N and Peltier, WR and Peterschmitt, JY and Pollard, D and Rind, D and Royer, JF and Schlesinger, ME and Syktus, J and Thompson, S and Valdes, P and Vettoretti, G and Webb, RS and Wyputta, U},
      title = {Monsoon changes for 6000 years ago: Results of 18 simulations from the Paleoclimate Modeling Intercomparison Project (PMIP)},
      journal = {Geophysical Research Letters},
      year = {1999},
      volume = {26},
      number = {7},
      pages = {859--862}
    }
    					
    Thompson1999 Thompson, R.S.; Anderson, K.H. & Bartlein, P.J. Atlas of Relations Between Climatic Parameters and Distributions of Important Trees and Shrubs in North America 1999 School: U.S. Geological Survey Professional Paper 1650 A & B   techreport vegetation and climate
    BibTeX:
    @techreport{Thompson1999,
      author = {Thompson, RS and Anderson, KH and Bartlein PJ},
      title = {Atlas of Relations Between Climatic Parameters and Distributions of Important Trees and Shrubs in North America},
      school = {U.S. Geological Survey Professional Paper 1650 A & B},
      year = {1999},
      note = {http://pubs.usgs.gov/pp/p1650-a/}
    }
    					
    Ladd1998 Ladd, S.C.; Marcus, W.A. & Cherry, S. Differences in trace metal concentrations among fluvial morphologic units and implications for sampling 1998 Environmental Geology
    Vol. 36 (3-4) , pp. 259-270  
    article
    Abstract: This study examines the segregation of trace metals within and between
    fluvial morphologic units in sand-sized and finer bed sediments a
    cobble bed stream. The types of fluvial morphologic units sampled
    are low gradient riffles, high gradient riffles, glides, eddy drop
    zones, lateral scour pools, attached bars, and detached bars. Three
    to nine samples were collected from ten of each type of morphologic
    unit. All 12 metals show significantly different concentrations between
    some morphologic units in sediments smaller than 2 mm. Eddy drop
    zones and attached bars consistently have the highest metal concentrations,
    while low gradient riffles, high gradient riffles, and glides typically
    have the lowest concentrations. Metals showing the greatest between-unit
    variability are Al, Cr, Fe, Cu, and Ti, followed by Co, Mn, and Pb,
    while Mg, Mn, V, and Zn display relatively few differences between
    units. Lateral and longitudinal variations of metals within units
    are not significant, and there was no consistent, predictable variation
    in metal concentrations with distance downstream. Results indicate
    that metal studies in other gravel- and cobble-bed streams should
    include a reconnaissance survey to determine variations between morphologic
    units, stratify sampling by morphologic unit, and analyze spatial
    autocorrelation to determine sample spacing.
    BibTeX:
    @article{Ladd1998,
      author = {Ladd, SC and Marcus, WA and Cherry, S},
      title = {Differences in trace metal concentrations among fluvial morphologic units and implications for sampling},
      journal = {Environmental Geology},
      year = {1998},
      volume = {36},
      number = {3-4},
      pages = {259--270}
    }
    					
    Long1998 Long, C.J.; Whitlock, C.; Bartlein, P.J. & Millspaugh, S.H. A 9000-year fire history from the Oregon Coast Range, based on a high-resolution charcoal study 1998 Canadian Journal of Forest Research
    Vol. 28 (5) , pp. 774-787  
    article fire: paleo and modern
    Abstract: High-resolution analysis of macroscopic charcoal in sediment cores
    from Little Lake was used to reconstruct the fire history of the
    last 9000 years. Variations in sediment magnetism were examined to
    detect changes in allochthonous sedimentation associated with past
    fire occurrence. Fire intervals from ca. 9000 to 6850 calendar years
    BP averaged 110 +/- 20 years, when the climate was warmer and drier
    than today and xerophytic vegetation dominated. From ca. 6850 to
    2750 calendar years BP the mean fire interval lengthened to 160 +/-
    20 years in conjunction with the onset of cool humid conditions.
    Fire-sensitive species, such as Thuja plicata Donn ex D. Don, Tsuga
    heterophylla (Raf.) Sarg., and Picea sitchensis (Bong.) Carr., increased
    in abundance. At ca. 4000 calendar years BP, increases in allochthonous
    sedimentation increased the delivery of secondary charcoal to the
    site. From ca. 2750 calendar years BP to present, the mean fire interval
    increased to 230 +/- 30 years as cool humid conditions and mesophytic
    taxa prevailed. The Little Lake record suggests that fire frequency
    has varied continuously on millennial time scales as a result of
    climate change and the present-day fire regime has been present for
    no more than 1000 years.
    BibTeX:
    @article{Long1998,
      author = {Long, CJ and Whitlock, C and Bartlein, PJ and Millspaugh, SH},
      title = {A 9000-year fire history from the Oregon Coast Range, based on a high-resolution charcoal study},
      journal = {Canadian Journal of Forest Research},
      year = {1998},
      volume = {28},
      number = {5},
      pages = {774--787},
      note = {http://geography.uoregon.edu/envchange/figures/Long-etal-CJFR-1998-figs/index.html}
    }
    					
    Marcus1998 Marcus, W.A.; Milner, G. & Maxwell, B. Spotted knapweed distribution in stock camps and trails of the Selway-Bitterroot Wilderness 1998 Great Basin Naturalist
    Vol. 58 (2) , pp. 156-166  
    article
    Abstract: This article documents spotted knapweed (Centaurea maculosa Lam.)
    in 30 campsites and along 5 trails in the Selway-Bitterroot Wilderness
    and assesses the role of disturbance and environmental factors in
    controlling infestation. Spotted knapweed was present in only 6 of
    30 surveyed campsites and limited portions of all 5 trails that were
    sampled. All spotted knapweed in camps was below 1700 m elevation,
    in open canopy, and in areas with an opportunity class disturbance
    ranking of 3 or 4. Overall disturbance levels measured using U.S.
    Forest Service Site Impact Worksheets (SIWs) did not help predict
    occurrence of spotted knapweed, although bare mineral soil, vegetation
    loss, and development variables of SIWs provide some explanation
    of spotted knapweed presence or absence. There was no significant
    difference in knapweed frequency between areas used predominantly
    by horses and those used by humans within camps. Over 95% of spotted
    knapweed along trails was found within 0.5 km of the trailhead, occurred
    within 4.6 m of the trail, and had low reproductive potential. If
    the Bitterroot portion of the Selway-Bitterroot Wilderness is representative
    of forested wilderness areas in the Northern Rockies, then the perceived
    threat of spotted knapweed to wilderness areas may substantially
    exceed the actual danger in many instances. Study findings indicate
    that managers should conduct surveys before initiating costly control
    measures in wilderness areas, that eradication may be a viable alternative
    when spotted knapweed numbers are this low, and that regulations
    promoting minimum-impact camping should reduce spotted knapweed infestation.
    BibTeX:
    @article{Marcus1998,
      author = {Marcus, WA and Milner, G and Maxwell, B},
      title = {Spotted knapweed distribution in stock camps and trails of the Selway-Bitterroot Wilderness},
      journal = {Great Basin Naturalist},
      year = {1998},
      volume = {58},
      number = {2},
      pages = {156--166}
    }
    					
    McCarty1998 McCarty, D.K.; Moore, J.N. & Marcus, W.A. Mineralogy and trace element association in an acid mine drainage iron oxide precipitate; comparison of selective extractions 1998 Applied Geochemistry
    Vol. 13 (2) , pp. 165-176  
    article
    Abstract: Mineral and trace element characterization of an Fe-rich precipitate
    from an acid mine system was accomplished by X-ray diffraction (XRD),
    differential X-ray diffraction, and ICP chemical analysis. A primary
    objective was to evaluate the effectiveness of common selective dissolution
    treatments in determining the association of minerals with potentially
    toxic trace elements; The precipitate consisted primarily of goethite,
    a poorly crystalline phase resembling synthetic ferrihydrite, dolomite
    and gypsum in clay-size fractions. The ammonium oxalate and EDTA
    treatments, which are thought by some workers to dissolve only poorly
    crystalline phases, were found to dissolve a significant amount of
    crystalline goethite. However, the oxalate extraction did dissolve
    more ferrihydrite than the other treatments tested. A solution of
    0.1 M hydroxylamine hydrochloride in 0.1 M HNO3, which is thought
    by some to dissolve mostly the highly soluble Mn-oxides was found
    to also dissolve goethite, as did 0.25 M hydroxylamine hydrochloride
    in 25% (v/v) acetic acid, 0.25 M hydroxylamine hydrochloride in 0.25
    M HCl, 0.5 M HCl, and Na-dithionite buffered with Na-citrate and
    1.0 M NaHCO3. Both trace and major elements that were extracted with
    the various treatments were found to vary significantly and non-systematically
    when compared to the proportion of total extractable Fe. These selective
    extractions cannot be used to make reliable conclusions about trace
    metal and mineral associations. Gypsum was identified by XRD in clay-size
    separations from the sample, but this phase was not detected in diffraction
    scans of the bulk sample. This finding indicates that individual
    phases can be segregated by particle size. (C) 1998 Elsevier Science
    Ltd. All rights reserved.
    BibTeX:
    @article{McCarty1998,
      author = {McCarty, DK and Moore, JN and Marcus, WA},
      title = {Mineralogy and trace element association in an acid mine drainage iron oxide precipitate; comparison of selective extractions},
      journal = {Applied Geochemistry},
      year = {1998},
      volume = {13},
      number = {2},
      pages = {165--176}
    }
    					
    Mock1998 Mock, C.J.; Bartlein, P.J. & Anderson, P.M. Atmospheric circulation patterns and spatial climatic variations in Beringia 1998 International Journal of Climatology
    Vol. 18 (10) , pp. 1085-1104  
    article synoptic climatology
    Abstract: Analyses of more than 40 years of climatic data reveal intriguing
    spatial variations in climatic patterns for Beringia (North-eastern
    Siberia and Alaska), aiding the understanding of the hierarchy of
    climatic controls that operate at different spatial scales within
    the Arctic. A synoptic climatology, using a subjective classification
    methodology on January and July sea level pressure, and July 500
    hPa height anomaly patterns, identified 13 major atmospheric circulation
    patterns (26 pairs consisting of 13 synoptic/temperature and 13 synoptic/precipitation
    comparisons) that occur over Beringia. Composite anomaly maps of
    circulation, temperature, and precipitation described the spatial
    variability of surface climatic responses to circulation. Results
    indicate that nine synoptic pairs yield homogeneous surface climatic
    anomaly patterns throughout most of Beringia. However, many of the
    surface climatic responses illustrate heterogeneous anomaly patterns
    as a result of variations in circulation controls, such as troughing
    over East Asia and the Pacific subtropical high superimposed over
    topography, with small shifts in atmospheric circulation dramatically
    altering spatial variations of anomaly patterns. Distinctive contrasts
    in climatic responses, as suggested from ten synoptic pairs, are
    clearly evident for Western Beringia versus Eastern Beringia. These
    results offer important implications for scholars interested in assessing
    late Quaternary climatic change in the region from interannual to
    millennial timescales. (C) 1998 Royal Meteorological Society.
    BibTeX:
    @article{Mock1998,
      author = {Mock, CJ and Bartlein, PJ and Anderson, PM},
      title = {Atmospheric circulation patterns and spatial climatic variations in Beringia},
      journal = {International Journal of Climatology},
      year = {1998},
      volume = {18},
      number = {10},
      pages = {1085--1104},
      note = {http://geography.uoregon.edu/envchange/figures/Mock-etal-IntJClim-1998-figs/IntJClim.htm}
    }
    					
    Shafer1998 Shafer, S.L. & Murphy, A.B. The Territorial Strategies of IGO's: Implications for Environment and Development 1998 Global Governance
    Vol. 4 , pp. 257-274  
    article human dimensions of climate change
    BibTeX:
    @article{Shafer1998,
      author = {Shafer, SL and Murphy, AB},
      title = {The Territorial Strategies of IGO's: Implications for Environment and Development},
      journal = {Global Governance},
      year = {1998},
      volume = {4},
      pages = {257-274},
      note = {http://geography.uoregon.edu/envchange/figures/Shafer-and-Murphy-GlobalGov-1998-figs/igo.html}
    }
    					
    Thompson1998 Thompson, R.S.; Hostetler, S.W.; Bartlein, P.J. & Anderson, K.H. A Strategy for Assessing Potential Future Changes in Climate, Hydrology, and Vegetation in the Western United States 1998 (1153) School: U.S. Geoglogical Survey Circular   techreport future vegetation change
    BibTeX:
    @techreport{Thompson1998,
      author = {Thompson, RS and Hostetler, SW and Bartlein, PJ and Anderson, KH},
      title = {A Strategy for Assessing Potential Future Changes in Climate, Hydrology, and Vegetation in the Western United States},
      school = {U.S. Geoglogical Survey Circular},
      year = {1998},
      number = {1153},
      note = {http://geography.uoregon.edu/envchange/figures/circular/index.html}
    }
    					
    Webb1998 Webb, T.; Anderson, K.H.; Bartlein, P.J. & Webb, R.S. Late Quaternary climate change in eastern North America: A comparison of pollen-derived estimates with climate model results 1998 Quaternary Science Reviews
    Vol. 17 (6-7) , pp. 587-606  
    article
    Abstract: Late Quaternary pollen data from eastern North America and pollen-climate
    response surfaces provide tests of the climate simulations from Version
    1 of the National Center for Atmospheric Research (NCAR) Community
    Climate Model (CCM1) for 21, 16, 14, 11, and 6 ka. The model results
    are also compared to those from Version 0 of the NCAR model (CCM0).
    In contrast to CCM0, CCM1 used a slab ocean model to compute sea
    surface temperatures, included a seasonal cycle, and computed soil
    moisture. It also used an improved set of boundary conditions from
    21 to 6 ka. In eastern North America, CCM 1 simulated lower temperatures
    at the last glacial maximum (LGM) 21,000 years ago than did CCM0
    and therefore was in better agreement with the pollen data than the
    CCM0 simulations were. The simulations by CCM 1 for mean July temperatures
    from 16 to 11 ka, however, were much higher than those by CCM0 and
    were higher than present for much of the area south of the Laurentide
    ice sheet. These simulated conditions differ markedly from those
    reconstructed from the pollen data, which indicate July temperatures
    significantly lower than present from 16 to 11 ka. At 6 ka, CCM 1
    simulated climate conditions similar to today and therefore not too
    different from those simulated by CCM0 or those inferred from the
    pollen data. For 6 Era in the upper Midwest, however, CCM1 simulated
    moisture conditions similar to present, which is an improvement over
    CCM0. However, the new simulation still does not match the drier-than-present
    conditions inferred from the pollen data. Derailed analysis of the
    circulation variables and the surface-energy-budget terms simulated
    by CCM1 show that both dynamic and thermodynamic factors contributed
    to the major discrepancy in July temperatures from 16 to 11 ka. The
    simulated glacial anticyclone created less cloudiness and rainfall
    south of the ice sheet, and these conditions allowed the increased
    summertime insolation from 16 to 11 ka to overheat the surface. The
    impact of the ice sheet on model dynamics therefore led to overestimation
    of summer temperatures south of the ice for this time period. (C)
    1998 Elsevier Science Ltd. All rights reserved.
    BibTeX:
    @article{Webb1998,
      author = {Webb, T and Anderson, KH and Bartlein, PJ and Webb, RS},
      title = {Late Quaternary climate change in eastern North America: A comparison of pollen-derived estimates with climate model results},
      journal = {Quaternary Science Reviews},
      year = {1998},
      volume = {17},
      number = {6-7},
      pages = {587--606}
    }
    					
    Bartlein1997 Bartlein, P.J.; Whitlock, C. & Shafter, S.L. Future climate in the Yellowstone National Park region and its potential impact on vegetation 1997 Conservation Biology
    Vol. 11 (3) , pp. 782-792  
    article future vegetation change
    Abstract: Biotic responses to future changes in global climate are difficult
    to project for a particular region because the responses involve
    processes that operate at many spatial scales. This difficulty is
    exacerbated in mountainous regions, where future vegetation changes
    are often portrayed as simple upward displacements of vegetation
    zones in response to warming. We examine the scope of future responses
    that may occur in a mountainous area by illustrating the potential
    distributions of selected tree taxa in the region of Yellowstone
    National Park. The output of a coarse-resolution climate model that
    incorporated a doubling of carbon dioxide concentration in the atmosphere
    was interpolated onto a 5-minute grid of topographically adjusted
    climate data. The output was also used as input into statistical
    relationships between the occurrence of individual taxa and climate.
    The simulated vegetation changes include a combination of elevational
    and directional range adjustments. The range of high-elevation species
    decreases, and some species become regionally extirpated. The new
    communities have no analogue in the present-day vegetation because
    they mix low-elevation montane species currently in the region with
    extralocal species from the northern and central Rocky Mountains
    and Pacific Northwest. The projected climate changes within the Yellowstone
    region and the individualism displayed by species in their potential
    range adjustments are equal or greater than the changes seen in the
    paleoecologic record during previous warming intervals. Although
    the results support conservation strategies that include habitat
    connectivity, the magnitude of the changes may exceed the ability
    of species to adjust their ranges. The predicted patterns call into
    question the adequacy of current management objectives to cope with
    the scope of future changes.
    BibTeX:
    @article{Bartlein1997,
      author = {Bartlein, PJ and Whitlock, C and Shafter, SL},
      title = {Future climate in the Yellowstone National Park region and its potential impact on vegetation},
      journal = {Conservation Biology},
      year = {1997},
      volume = {11},
      number = {3},
      pages = {782--792}
    }
    					
    Bartlein1997a Bartlein, P.J. Huntley, B.; Cramer, W.; Morgan, A.V.; Prentice, I.C. & Allen, J.R.M. (Hrsg.) Past environmental changes: characteristic features of Quaternary climate variations ( Past and Future Rapid Environmental Changes: The Spatial and Evolutionary Responses of Terrestrial Biota ) 1997 NATO ASI Series Past and Future Rapid Environmental Changes: The Spatial and Evolutionary Responses of Terrestrial Biota
    Vol. 147 , pp. 11-29  
    inbook paleoclimatic analysis and data-model comparisons vegetation and climate
    BibTeX:
    @inbook{Bartlein1997a,
      author = {Bartlein, PJ},
      title = {Past and Future Rapid Environmental Changes: The Spatial and Evolutionary Responses of Terrestrial Biota},
      journal = {NATO ASI Series},
      publisher = {NATO ASI Series},
      year = {1997},
      volume = {147},
      pages = {11-29}
    }
    					
    Gavin1997 Gavin, D.G. & Peart, D.R. Spatial structure and regeneration of Tetramerista glabra in peat swamp rain forest in Indonesian Borneo 1997 Plant Ecology
    Vol. 131 (2) , pp. 223-231  
    article
    Abstract: We examined the spatial structure and regeneration of Tetramerista
    glabra, a dominant canopy tree in peat swamp rain forest in Borneo
    (West Kalimantan, Indonesia). T. glabra has strong spatial structure
    that changes dramatically during the life cycle, seedlings were highly
    aggregated, saplings were random and trees were evenly distributed.
    Germination and seedling relative growth were highest within canopy
    gaps, but seedling densities were highest at gap edges. Concentration
    of seedlings in gap edges, rather than localized seed dispersal,
    was responsible for seedling patchiness. The slope of the relationship
    between relative growth rate and seedling height decreased from gap,
    to gap edge to understory habitats, suggesting that competition within
    the seedling layer is more important in gaps than in the understory.
    The processes that break down seedling aggregation, leading to over-dispersion
    of trees, must be density dependent, but remain unknown.
    BibTeX:
    @article{Gavin1997,
      author = {Gavin, DG and Peart, DR},
      title = {Spatial structure and regeneration of Tetramerista glabra in peat swamp rain forest in Indonesian Borneo},
      journal = {Plant Ecology},
      year = {1997},
      volume = {131},
      number = {2},
      pages = {223--231}
    }
    					
    Magilligan1997 Magilligan, F.J. & McDowell, P.F. Stream channel adjustments following elimination of cattle grazing 1997 Journal of the American Water Resources Association
    Vol. 33 (4) , pp. 867-878  
    article
    Abstract: Cattle grazing practices in the western United States have contributed
    to widespread riparian degradation resulting in unstable channel
    morphologies and the loss of fish habitat. Because of prolonged disturbance,
    numerous riparian areas oil both public and private lands have been
    fenced to exclude cattle in order to promote vegetation establishment
    and riparian improvement. We selected four gravel-bedded, steep alluvial
    streams in eastern Oregon with cattle exclosures greater than 14
    years old for an analysis of geomorphic adjustments following the
    removal of cattle grazing. We compare channels inside exclosures
    and in adjacent grazed reaches to identify the salient stream channel
    properties that respond to the removal of riparian stresses and to
    document the magnitude of these changes. Results indicate that significant
    changes occur, with reductions in bankfull dimensions and increases
    in pool area being the most common and identifiable changes. At all
    four sites, bankfull widths are narrower by 10 to 20 percent, and
    the percentage of channel area occupied by pools is higher in the
    exclosure by 8 to 15 percent. The increase in pool area is primarily
    offset by a reduction in the percent glide area. Not all of the channel
    properties demonstrate adjustment, indicating that perhaps 14 years
    is an insufficient duration for these variables to adjust.
    BibTeX:
    @article{Magilligan1997,
      author = {Magilligan, FJ and McDowell, PF},
      title = {Stream channel adjustments following elimination of cattle grazing},
      journal = {Journal of the American Water Resources Association},
      year = {1997},
      volume = {33},
      number = {4},
      pages = {867--878}
    }
    					
    Mcdowell1997 McDowell, P.F. & Magilligan, F.J. Response of Stream Channels to Removal of Cattle Grazing Disturbance: Overview of Western U.S. Exclosure Studies ( Management of Landscapes Disturbed by Channel Incision ) 1997 Management of Landscapes Disturbed by Channel Incision , pp. 469-475   inbook fluvial geomorphology
    BibTeX:
    @inbook{Mcdowell1997,
      author = {McDowell, PF and Magilligan, FJ},
      title = {Management of Landscapes Disturbed by Channel Incision},
      year = {1997},
      pages = {469-475}
    }
    					
    Whitlock1997 Whitlock, C. & Bartlein, P.J. Vegetation and climate change in northwest America during the past 125 kyr 1997 Nature
    Vol. 388 (6637) , pp. 57-61  
    article paleoclimatology and paleoecology
    Abstract: Vegetation records spanning the past 21 kyr in western North America
    display spatial patterns of change that reflect the influence of
    variations in the large-scale controls of climate(1). Among these
    controls are millennial-scale variations in the seasonal cycle of
    insolation and the size of the ice sheet, which affect regional climates
    directly through changes in temperature and net radiation, and indirectly
    by shifting atmospheric circulation. Longer vegetation records provide
    an opportunity to examine the regional response to different combinations
    of these large-scale controls, and whether non-climatic controls
    are important. But most of the longer North American records(2,3)
    are of insufficient quality to allow a robust test, and the Long
    European records(4-9) are in regions where the vegetation response
    to climate is often difficult to separate from the response to ecological
    and anthropogenic controls. Here we present a 125-kyr record of vegetation
    and climate change for the forest/steppe border of the eastern Cascade
    Range, northwest America. Pollen data disclose alternations of forest
    and steppe that are consistent with variations in summer insolation
    and global ice-volume, and vegetational transitions correlate well
    with the marine isotope-stage boundaries. The close relationship
    between vegetation and climate beyond the Last Glacial Maximum provides
    evidence that climate variations are the primary cause of regional
    vegetation change on millennial timescales, and that non-climatic
    controls are secondary.
    BibTeX:
    @article{Whitlock1997,
      author = {Whitlock, C and Bartlein, PJ},
      title = {Vegetation and climate change in northwest America during the past 125 kyr},
      journal = {Nature},
      year = {1997},
      volume = {388},
      number = {6637},
      pages = {57--61},
      note = {http://geography.uoregon.edu/envchange/figures/Whitlock-and-Bartlein-Nature-1997-figs/nature.htm}
    }
    					
    Birkeland1996 Birkeland, K.W. & Mock, C.J. Atmospheric Circulation Patterns Associated with Heavy Snowfall Events, Bridger Bowl, Montana, U.S.A. 1996 Mountain Research and Development
    Vol. 16 , pp. 281-286  
    article synoptic climatology
    BibTeX:
    @article{Birkeland1996,
      author = {Birkeland, KW and Mock, CJ},
      title = {Atmospheric Circulation Patterns Associated with Heavy Snowfall Events, Bridger Bowl, Montana, U.S.A.},
      journal = {Mountain Research and Development},
      year = {1996},
      volume = {16},
      pages = {281-286},
      note = {http://geography.uoregon.edu/envchange/figures/Mock-and-Birkeland-MRD-1996-figs/mtsnow.htm}
    }
    					
    Kutzbach1996 Kutzbach, J.E.; Bartlein, P.J.; Foley, J.A.; Harrison, S.P.; Hostetler, S.W.; Liu, Z.; Prentice, I.C. & Webb, T. Potential role of vegetation feedback in the climate sensitivity of high-latitude regions: A case study at 6000 years BP 1996 Global Biogeochemical Cycles
    Vol. 10 (4) , pp. 727-736  
    article
    Abstract: Previous climate model simulations have shown that the configuration
    of the Earth's orbit during the early to mid-Holocene (approximately
    10-5 kyr) can account for the generally warmer-than-present conditions
    experienced by the high latitudes of the northern hemisphere. New
    simulations for 6 kyr with two atmospheric/mixed-layer ocean models
    (Community Climate Model, version 1, CCM1, and Global ENvironmental
    and Ecological Simulation of Interactive Systems, version 2, GENESIS
    2) are presented here and compared with results from two previous
    simulations with GENESIS 1 that were obtained with and without the
    albedo feedback due to climate-induced poleward expansion of the
    boreal forest. The climate model results are summarized in the form
    of potential vegetation maps obtained with the global BIOME model,
    which facilitates visual comparisons both among models and with pollen
    and plant macrofossil data recording shifts of the forest-tundra
    boundary. A preliminary synthesis shows that the forest limit was
    shifted 100-200 km north in most sectors. Both CCM1 and GENESIS 2
    produced a shift of this magnitude. GENESIS 1 however produced too
    small a shift, except when the boreal forest albedo feedback was
    included. The feedback in this case was estimated to have amplified
    forest expansion by approximately 50%. The forest limit changes also
    show meridional patterns (greatest expansion in central Siberia and
    little or none in Alaska and Labrador) which have yet to be reproduced
    by models. Further progress in understanding of the processes involved
    in the response of climate and vegetation to orbital forcing will
    require both the deployment of coupled atmosphere-biosphere-ocean
    models and the development df more comprehensive observational data
    sets.
    BibTeX:
    @article{Kutzbach1996,
      author = {Kutzbach, JE and Bartlein, PJ and Foley, JA and Harrison, SP and Hostetler, SW and Liu, Z and Prentice, IC and Webb, T},
      title = {Potential role of vegetation feedback in the climate sensitivity of high-latitude regions: A case study at 6000 years BP},
      journal = {Global Biogeochemical Cycles},
      year = {1996},
      volume = {10},
      number = {4},
      pages = {727--736}
    }
    					
    Marcus1996 Marcus, W.A. & Marcus, M.G. Geographer, explorer, friend: The worlds of Barry C. Bishop, 1932-1994 1996 Mountain Research and Development
    Vol. 16 (3) , pp. 193-198  
    article
    BibTeX:
    @article{Marcus1996,
      author = {Marcus, WA and Marcus, MG},
      title = {Geographer, explorer, friend: The worlds of Barry C. Bishop, 1932-1994},
      journal = {Mountain Research and Development},
      year = {1996},
      volume = {16},
      number = {3},
      pages = {193--198}
    }
    					
    Marcus1996a Marcus, M.G. & Marcus, W.A. Barry C. Bishop - In memoriam 1996 Mountain Research and Development
    Vol. 16 (3) , pp. 188-192  
    article
    BibTeX:
    @article{Marcus1996a,
      author = {Marcus, MG and Marcus, WA},
      title = {Barry C. Bishop - In memoriam},
      journal = {Mountain Research and Development},
      year = {1996},
      volume = {16},
      number = {3},
      pages = {188--192}
    }
    					
    Marcus1996b Marcus, W.A. Segment-scale patterns and hydraulics of trace metal concentrations in fine grain sediments of a cobble and boulder bed mountain stream, southeast Alaska 1996 Mountain Research and Development
    Vol. 16 (3) , pp. 211-220  
    article
    Abstract: This study documents and analyzes spatial patterns of variability
    in 12 trace metals in sand-size and finer sediments over a 2 km segment
    of a boulder and cobble bed mountain stream. The analysis focuses
    on concentrations rather than the total metal mass budget, because
    it is typically variations in metal concentrations that are important
    for assessing potential environmental impacts. There are no consistent
    downstream variations in metal concentrations, which indicates that
    there are no significant geochemical changes or external sources
    of metals in the study segment. In fact, much of the spatial variability
    within the stream segment appears to be random, although a dimensionless
    shear stress model predicts the majority of locations where peak
    concentrations of metals contained in heavy minerals occur. The dimensionless
    shear stress model, however, only predicts the potential for enrichment
    and many sites where potential enrichment is predicted contain low
    concentrations of metals. Peak concentrations do not appear to be
    associated with metal-rich sediment waves moving through the system,
    but instead are probably the result of local hydraulic variability.
    Sampling of boulder and cobble streams should be stratified by hydraulic
    environments in order to capture the full range of minimum and maximum
    metal concentrations within the stream system.
    BibTeX:
    @article{Marcus1996b,
      author = {Marcus, WA},
      title = {Segment-scale patterns and hydraulics of trace metal concentrations in fine grain sediments of a cobble and boulder bed mountain stream, southeast Alaska},
      journal = {Mountain Research and Development},
      year = {1996},
      volume = {16},
      number = {3},
      pages = {211--220}
    }
    					
    Mock1996 Mock, C.J. Climatic Controls and Spatial Variations of Precipitation in the Western United States 1996 Journal of Climate
    Vol. 9 , pp. 1111-1125  
    article synoptic climatology
    BibTeX:
    @article{Mock1996,
      author = {Mock, CJ},
      title = {Climatic Controls and Spatial Variations of Precipitation in the Western United States},
      journal = {Journal of Climate},
      year = {1996},
      volume = {9},
      pages = {1111-1125},
      note = {http://geography.uoregon.edu/envchange/figures/Mock-JClimate-1996-figs/Jclimate.htm}
    }
    					
    Bartlein1995 Bartlein, P.J.; Edwards, M.E.; Shafer, S.L. & Barker, E.D. Calibration of radiocarbon ages and the interpretation of paleoenvironmental records 1995 Quaternary Research
    Vol. 44 (3) , pp. 417-424  
    article paleoecology
    Abstract: Calibration of the radiocarbon timescale of paleoecological records
    is essential if they are to be explained correctly in terms of their
    governing ecological or climatological controls, The differences
    between calendar ages and radiocarbon ages that arise from variations
    in C-14 production through time can distort the chronologies of individual
    records and the interpretations based on them, Misleading impressions
    of synchrony or diachrony of events among multiple records can result,
    and estimates of the apparent duration of episodes and rates of sedimentation
    and local population changes can be biased, Displays of the temporal
    patterns of migration or extinction may also be affected, Spurious
    correlations may arise between records with radio carbon-controlled
    chronologies and time series of potential controls that are expressed
    on a calendar time scale, Support for particular explanations of
    features in a paleoecological record may vary depending on whether
    radiocarbon ages are calibrated or not, This situation is illustrated
    using the eastern Beringian Populus subzone as an example. When the
    radiocarbon ages that control the timing of the Populus subzone are
    calibrated, the contemporaneous decrease in ice volume and increase
    in summer insolation are implicated as the ultimate controls of the
    occurrence of the subzone. (C) 1995 University of Washington.
    BibTeX:
    @article{Bartlein1995,
      author = {Bartlein, PJ and Edwards, ME and Shafer, SL and Barker, ED},
      title = {Calibration of radiocarbon ages and the interpretation of paleoenvironmental records},
      journal = {Quaternary Research},
      year = {1995},
      volume = {44},
      number = {3},
      pages = {417--424}
    }
    					
    Clark1995 Clark, P.U. & Bartlein, P.J. Correlation of late Pleistocene glaciation in the western United States with North Atlantic Heinrich events 1995 Geology
    Vol. 23 (6) , pp. 483-486  
    article
    Abstract: A survey of the chronology of late Pleistocene glaciers in the western
    United States indicates a record of glacier advances during the last
    glaciation which is more variable than that predicted by orbital
    forcing. Numerical dating of late Pleistocene deposits from the Puget
    lobe of the Cordilleran ice sheet and alpine glaciers and ice caps
    in the Rocky Mountains and Cascade Range suggests that advances and
    retreats of these glaciers were in phase with episodes of growth
    and collapse of the Laurentide ice sheet associated with the North
    Atlantic Heinrich events. Specifically, the existing chronologies
    indicate that these glaciers were advancing to their terminal areas
    up to several thousand years before a Heinrich event and retreated
    shortly thereafter, Because midlatitude glaciers respond relatively
    rapidly to climate change, this complex record of glacial fluctuations
    suggests mechanisms of climate forcing in western North America that
    are in some way tied to Heinrich events, One possible mechanism involves
    southerly and northerly displacement of the jet stream across the
    western United States in response to growth and collapse of the Laurentide
    ice sheet.
    BibTeX:
    @article{Clark1995,
      author = {Clark, PU and Bartlein, PJ},
      title = {Correlation of late Pleistocene glaciation in the western United States with North Atlantic Heinrich events},
      journal = {Geology},
      year = {1995},
      volume = {23},
      number = {6},
      pages = {483--486}
    }
    					
    Marcus1995 Marcus, W.A.; Ladd, S.C. & Stoughton, J.A. Pebble counts and the role of user-dependent bias in documenting sediment size distributions 1995 Water Resources Research
    Vol. 31 (10) , pp. 2625-2631  
    article
    Abstract: Replicate subaqueous pebble counts show that measurement and selection
    bias can significantly affect sediment size distribution data. The
    standard deviation about replicate means increases linearly with
    sediment size and is independent of the sediment percentile (e.g.,
    d(50), d(84), etc.). For samples collected by one person, sampling
    error varies from 2 +/- 2.6 mm to 300 +/- 35.4 mm within one standard
    deviation. For samples collected by different individuals, sampling
    bias increases the error from 2 +/- 4.2 mm to 300 +/- 63.8 mm. Whenever
    possible, only one individual should select and measure pebbles,
    which improves the ability of the pebble count to delineate trends
    between sites or over time (although the absolute size values may
    be in error due to bias). Bias can be reduced by rigorous training
    of individuals, by using templates to measure sediment size, and
    by using grids on the stream bottom to select particles. If two or
    more individuals collect samples, they should conduct replicate samples
    to provide a basis for later calibration of results.
    BibTeX:
    @article{Marcus1995,
      author = {Marcus, WA and Ladd, SC and Stoughton, JA},
      title = {Pebble counts and the role of user-dependent bias in documenting sediment size distributions},
      journal = {Water Resources Research},
      year = {1995},
      volume = {31},
      number = {10},
      pages = {2625--2631}
    }
    					
    Mock1995 Mock, C.J. & Bartlein, P.J. Spatial variability of late-Quaternary paleoclimates in the western United States 1995 Quaternary Research
    Vol. 44 (3) , pp. 425-433  
    article modern climate analogues
    Abstract: Paleoclimatic interpretation of proxy data is complicated sometimes
    by the appearance of heterogeneous patterns of climatic responses
    across networks of sites. Modern climate analogues for the western
    United States, similar to those patterns of atmospheric circulation
    of 18,000 and 9000 yr B.P., were examined in order to explain such
    patterns of spatial heterogeneity, Modern analogues were defined
    by comparing modern atmospheric circulation patterns with those simulated
    by general circulation models, Maps of temperature and precipitation
    anomalies of the modern analogues reveal patterns of spatial heterogeneity,
    which resemble the patterns of effective moisture compiled from paleoclimatic
    data, January 1957 was found to be a reasonable 18,000 yr B.P. analogue,
    and it features isolated areas of increased wetness in the northern
    Great Basin and increased dryness in the Northwest interior, Analogues
    for 9000 yr B.P. from a composite of 11 Augusts display patterns
    of spatial heterogeneity of effective moisture over most of the mountainous
    areas, The analogues suggest that spatial heterogeneity of climate
    is the rule rather than the exception over much of the western United
    States, with the climatic anomalies at any particular time representing
    the outcome of the mediation of large-scale atmospheric circulation
    controls by smaller scale topographic features. (C) 1995 University
    of Washington.
    BibTeX:
    @article{Mock1995,
      author = {Mock, CJ and Bartlein, PJ},
      title = {Spatial variability of late-Quaternary paleoclimates in the western United States},
      journal = {Quaternary Research},
      year = {1995},
      volume = {44},
      number = {3},
      pages = {425--433}
    }
    					
    Whitlock1995 Whitlock, C.; Bartlein, P.J. & Van Norman, K.J. Stability of Holocene climate regimes in the Yellowstone region 1995 Quaternary Research
    Vol. 43 (3) , pp. 433-436  
    article paleoclimatology
    Abstract: A 12,500-yr pollen record from Loon Lake, Wyoming provides information
    on the climate history of the southwestern margin of Yellowstone
    National Park. The environmental reconstruction was used to evaluate
    hypotheses that address spatial variations in the Holocene climate
    of mountainous regions. Loon Lake lies within the summer-dry/winter-wet
    climate regime. An increase in xerophytic pollen taxa suggests drier-than-present
    conditions between ca. 9500 and 5500 C-14 yr B.P. This response is
    consistent with the hypothesis that increased summer radiation and
    the expansion of the east Pacific subtropical high-pressure system
    in the early Holocene intensified summer drought at locations within
    the summer-dry/winter-wet regime. This climate history contrasts
    with that of nearby sites in the summer-wet/winter-dry region, which
    were under the influence of stronger summer monsoonal circulation
    in the early Holocene. The Loon Lake record implies that the location
    of contrasting climate regimes did not change in the Yellowstone
    region during the Holocene. The amplitude of the regimes, however,
    was determined by the intensity of circulation features and these
    varied with temporal changes in the seasonal distribution of solar
    radiation. (C) 1995 University of Washington.
    BibTeX:
    @article{Whitlock1995,
      author = {Whitlock, C and Bartlein, PJ and Van Norman, KJ},
      title = {Stability of Holocene climate regimes in the Yellowstone region},
      journal = {Quaternary Research},
      year = {1995},
      volume = {43},
      number = {3},
      pages = {433--436}
    }
    					
    Anderson1994 Anderson, P.M.; Bartlein, P.J. & Brubaker, L.B. Late Quaternary history of tundra vegetation in northwestern Alaska 1994 Quaternary Research
    Vol. 41 (3) , pp. 306-315  
    article
    Abstract: Pollen analysis of a new core from Joe Lake indicates that the late
    Quaternary vegetation of northwestern Alaska was characterized by
    four tundra and two forest-tundra types. These vegetation types were
    differentiated by combining quantitative comparisons of fossil and
    modern pollen assemblages with traditional, qualitative approaches
    for inferring past vegetation, such as the use of indicator species.
    Although imprecisely dated, the core probably spans at least the
    past 40,000 yr. A graminoid-Salix tundra dominated during the later
    and early portions of the glacial record. The middle glacial interval
    and the transition from glacial to interglacial conditions are characterized
    by a graminoid-Betula-Salix tundra. A Populus forest-Betula shrub
    tundra existed during the middle potion of this transition, being
    replaced in the early Holocene by a Betula-Alnus shrub tundra. The
    modern Picea forest-shrub tundra was established by the middle Holocene.
    These results suggest that the composition of modem tundra communities
    in northwestern Alaska developed relatively recently and that throughout
    much of the late Quaternary, tundra communities were unlike the predominant
    types found today in northern North America. Although descriptions
    of vegetation variations within the tundra will always be restricted
    by the innate taxonomic limitations of their herb-dominated pollen
    spectra, the application of multiple interpretive approaches improves
    the ability to reconstruct the historical development of this vegetation
    type. (C) 1994 University of Washington.
    BibTeX:
    @article{Anderson1994,
      author = {Anderson, PM and Bartlein, PJ and Brubaker, LB},
      title = {Late Quaternary history of tundra vegetation in northwestern Alaska},
      journal = {Quaternary Research},
      year = {1994},
      volume = {41},
      number = {3},
      pages = {306--315}
    }
    					
    Hostetler1994 Hostetler, S.W.; Giorgi, F.; Bates, G.T. & BARTLEIN, P.J. Lake-atmosphere feedbacks associated with paleolakes Bonneville and Lahontan 1994 Science
    Vol. 263 (5147) , pp. 665-668  
    article
    Abstract: A high-resolution, regional climate model nested within a general
    circulation model was used to study the interactions between the
    atmosphere and the large Pleistocene lakes in the Great Basin of
    the United States. Simulations for January and July 18,000 years
    ago indicate that moisture provided by synoptic-scale atmospheric
    circulation features was the primary component of the hydrologic
    budgets of Lakes Lahontan and Bonneville. In addition, lake-generated
    precipitation was a substantial component of the hydrologic budget
    of Lake Bonneville at that time. This local lake-atmosphere interaction
    may help explain differences in the relative sizes of these lakes
    18,000 years ago.
    BibTeX:
    @article{Hostetler1994,
      author = {Hostetler, SW and Giorgi, F and Bates, GT and BARTLEIN, PJ},
      title = {Lake-atmosphere feedbacks associated with paleolakes Bonneville and Lahontan},
      journal = {Science},
      year = {1994},
      volume = {263},
      number = {5147},
      pages = {665--668}
    }
    					
    Vassiljev1994 Vassiljev, J.; Harrison, S.P.; Hostetler, S. & Bartlein, P.J. Simulation of long-term thermal-characteristics of 3 Estonian lakes 1994 Journal of Hydrology
    Vol. 163 (1-2) , pp. 107-123  
    article
    Abstract: A one-dimensional surface energy-balance lake model, coupled to a
    thermodynamic model of lake ice, is used to simulate variations in
    the temperature of and evaporation from three Estonian lakes: Karujarv,
    Viljandi and Kirjaku. The model is driven by daily climate data,
    derived by cubic-spline interpolation from monthly mean data, and
    was run for periods of 8 years (Kirjaku) up to 30 years (Viljandi).
    Simulated surface water temperature is in good agreement with observations:
    mean differences between simulated and observed temperatures are
    from -0.8-degrees-C to + 0.1-degrees-C. The simulated duration of
    snow and ice cover is comparable with observed. However, the model
    generally underpredicts ice thickness and overpredicts snow depth.
    Sensitivity analyses suggest that the model results are robust across
    a wide range (0.1-2.0 m-1) of lake extinction coefficient: surface
    temperature differs by less than 0.5-degrees-C between extreme values
    of the extinction coefficient. The model results are more sensitive
    to snow and ice albedos. However, changing the snow (0.2-0.9) and
    ice (0.15-0.55) albedos within realistic ranges does not improve
    the simulations of snow depth and ice thickness. The underestimation
    of ice thickness is correlated with the overestimation of snow cover,
    since a thick snow layer insulates the ice and limits ice formation.
    The overestimation of snow cover results from the assumption that
    all the simulated winter precipitation occurs as snow, a direct consequence
    of using daily climate data derived by interpolation from mean monthly
    data.
    BibTeX:
    @article{Vassiljev1994,
      author = {Vassiljev, J and Harrison, SP and Hostetler, S and Bartlein, PJ},
      title = {Simulation of long-term thermal-characteristics of 3 Estonian lakes},
      journal = {Journal of Hydrology},
      year = {1994},
      volume = {163},
      number = {1-2},
      pages = {107--123}
    }
    					
    Gavin1993 Gavin, D.G. & Peart, D.R. Effects of beech bark disease on the growth of american beech (Fagus grandifolia) 1993 Canadian Journal of Forest Research
    Vol. 23 (8) , pp. 1566-1575  
    article
    Abstract: We studied radial growth reduction in American beech (Fagus grandifolia
    Ehrh.) in relation to the level of defect induced by beech bark disease,
    in second-growth and old-growth northern hardwoods stands in New
    Hampshire. In the second-growth stand at Moose Mountain (n = 243
    trees), 1989-1990 radial growth declined significantly with increasing
    severity of external symptoms. The severity of external symptoms
    increased significantly with DBH. To examine temporal trends, internal
    defect induced by the disease was quantified as the percentage of
    growth sheath cankered in each year, by cross-sectioning a subsample
    of 40 trees. Internal defect first appeared in 1950, increased through
    1969, then declined until a major pulse of infection in the period
    1983-1987. Sectioned trees were divided into infection classes based
    on a cumulative measure of internal defect. Growth of severely infected
    trees first fell below that of uninfected trees in 1965, and was
    consistently lower after 1972. The growth ratio of severely infected
    to uninfected trees generally declined from 1960 to 1990; by 1990,
    growth of severely infected trees was reduced by more than 40% relative
    to healthy trees. This decline in the growth ratio corresponded well
    to the increase in cumulative internal defect in the stand, suggesting
    that disease stress had cumulative effects on tree vigor. The relation
    between beech bark disease and growth was also examined on an individual-tree
    basis; recent growth decline was significantly greater for trees
    with higher levels of internal defect. Internal defect was a better
    predictor of growth trends than was external defect. External defect
    was only moderately correlated with internal defect (r2 = 0.503).
    In the old-growth stand at Bartlett. N.H. (n = 40 trees) infection
    was quantified from external symptoms only. As in the second-growth
    stand, the growth of severely infected trees in the old-growth stand
    fell significantly below that of uninfected trees. However, significant
    differences in growth between uninfected and severely infected trees
    occurred earlier in the old-growth stand, first appearing in 1949.
    Delayed growth reductions in the second-growth stand may be associated
    with changes in shade and moisture affecting the beech scale, changes
    in tree physiological stress after selective logging, or changes
    in the density of large trees. Beech may survive long periods of
    infection by beech bark disease. However, our results demonstrate
    clearly that beech bark disease has reduced the growth of American
    beech in both second-growth and old-growth northern hardwoods stands
    for several decades.
    BibTeX:
    @article{Gavin1993,
      author = {Gavin, DG and Peart, DR},
      title = {Effects of beech bark disease on the growth of american beech (Fagus grandifolia)},
      journal = {Canadian Journal of Forest Research},
      year = {1993},
      volume = {23},
      number = {8},
      pages = {1566--1575}
    }
    					
    Marcus1993 Marcus, W.A.; Nielsen, C.C. & Cornwell, J.C. Sediment budget-based estimates of trace-metal inputs to a Chesapeake estuary 1993 Environmental Geology
    Vol. 22 (1) , pp. 1-9  
    article fluvial systems pollution
    Abstract: This article evaluates whether a sediment budget for the South River,
    Maryland, can be coupled with metals data from sediment cores to
    identify and quantify sources of historic metal inputs to marsh and
    subtidal sediments along the estuary. Metal inputs to estuarine marsh
    sediments come from fluvial runoff and atmospheric deposition. Metal
    inputs to subtidal sediments come from atmospheric deposition, fluvial
    runoff, coastal erosion, and estuarine waters. The metals budget
    for the estuary indicates that metal inputs from coastal erosion
    have remained relatively constant since 1840. Historical variations
    in metal contents of marsh sediments have probably resulted primarily
    from increasing atmospheric deposition in this century. but prior
    to 1900 may reflect changing fluvial sources, atmospheric inputs,
    or factors not quantified by the budget. Residual Pb, Cu, and Zn
    in the marsh sediments not accounted for by fluvial inputs was low
    to moderate in 1840, decreased to near zero circa 1910, and by 1987
    had increased to levels that were one to ten times greater than those
    of 1840. Sources of variability in subtidal cores could not be clearly
    discerned because of geochemical fluxes, turbulent mixing, and bioturbation
    within the cores. The sediment-metal budgeting approach appears to
    be a viable method for delineating metal sources in small, relatively
    simple estuarine systems like the South River and in systems where
    recent deposition (for example, prograding marshes) prevents use
    of deep core analysis to identify ''background'' levels of metal.
    In larger systems or systems with more variable sources of sediment
    and metal input, however, assumptions and measurement errors in the
    metal budgeting approach suggest that deep core analysis and normalization
    techniques are probably preferable for identifying anthropogenic
    impacts.
    BibTeX:
    @article{Marcus1993,
      author = {Marcus, WA and Nielsen, CC and Cornwell, JC},
      title = {Sediment budget-based estimates of trace-metal inputs to a Chesapeake estuary},
      journal = {Environmental Geology},
      year = {1993},
      volume = {22},
      number = {1},
      pages = {1--9}
    }
    					
    Prentice1993 Prentice, I.C.; Sykes, M.T.; Lautenschlager, M.; Harrison, S.P.; Denisekko, O. & BARTLEIN, P.J. Modeling global vegetation patterns and terrestrial carbon storage at the Last Glacial Maximum 1993 Global Ecology and Biogeography Letters
    Vol. 3 (3) , pp. 67-76  
    article
    Abstract: Global patterns of potential natural vegetation were simulated for
    present and last glacial maximum (LGM) climates. The LGM simulation
    showed good agreement with available evidence, most importantly in
    the humid tropics. Simple calculations based on these simulations
    indicate that terrestrial carbon storage increased by 300-700 Pg
    C after the LGM. The range is due to uncertainties in the mean carbon
    storage values for different biomes, and in the amount of carbon
    in boreal peats. These results are consistent with the global change
    in ocean delta-C-13, inferred from measurements on benthic foraminifera,
    reflecting the increased storage of isotopically light carbon on
    land.
    BibTeX:
    @article{Prentice1993,
      author = {Prentice, IC and Sykes, MT and Lautenschlager, M and Harrison, SP and Denisekko, O and BARTLEIN, PJ},
      title = {Modeling global vegetation patterns and terrestrial carbon storage at the Last Glacial Maximum},
      journal = {Global Ecology and Biogeography Letters},
      year = {1993},
      volume = {3},
      number = {3},
      pages = {67--76}
    }
    					
    Whitlock1993 Whitlock, C. & Bartlein, P.J. Spatial variations of Holocene climatic change in the Yellowstone Region 1993 Quaternary Research
    Vol. 39 (2) , pp. 231-238  
    article paleoclimatology
    BibTeX:
    @article{Whitlock1993,
      author = {Whitlock, C and Bartlein, PJ},
      title = {Spatial variations of Holocene climatic change in the Yellowstone Region},
      journal = {Quaternary Research},
      year = {1993},
      volume = {39},
      number = {2},
      pages = {231--238}
    }
    					
    Harrison1992 Harrison, S.P.; Prentice, I.C. & Bartlein, P.J. Influence of insolation and glaciation on atmospheric circulation in the North Atlantic sector - implications of general-circulation model experiments for the late Quaternary climatology of Europe 1992 Quaternary Science Reviews
    Vol. 11 (3) , pp. 283-299  
    article
    Abstract: Atmospheric general circulation models have been used to simulate
    the sensitivity of regional climates to Late Quaternary changes in
    insolation, ice sheets and atmospheric CO2. Model results for full-glacial
    conditions (18 ka) show the Atlantic Westerly jet strengthened and
    shifted south, a corresponding southward shift of the Icelandic low
    and a strengthening and northward shift of the subtropical anticyclone
    (STA). A glacial anticyclone developed over the European ice sheet
    and cold, dry conditions prevailed over much of Europe. The full-glacial
    climate anomaly for the North Atlantic sector is explained by a combination
    of low atmospheric CO2 (reducing global surface temperatures) and
    circulation changes caused by the ice sheets. By the Early Holocene
    (9 ka) the ice sheets were much reduced while the orbital anomaly
    was near its maximum, producing midcontinental summer warming and
    winter cooling and a reduced latitudinal temperature gradient in
    the northern hemisphere in both seasons. The jet and the Icelandic
    low were displaced to north of their present position, producing
    strong onshore flow and mild, wet winters in northern Europe, while
    the STA was also shifted northwards, producing offshore flow and
    dry summers in the same region. During the late-glacial transition
    the effects of insolation and glaciation were antagonistic for some
    features of the circulation and synergistic for others. The model
    results suggest palaeoclimatic hypotheses that could be directly
    tested by comparison with palaeoclimatic data mapped at a synoptic
    scale.
    BibTeX:
    @article{Harrison1992,
      author = {Harrison, SP and Prentice, IC and Bartlein, PJ},
      title = {Influence of insolation and glaciation on atmospheric circulation in the North Atlantic sector - implications of general-circulation model experiments for the late Quaternary climatology of Europe},
      journal = {Quaternary Science Reviews},
      year = {1992},
      volume = {11},
      number = {3},
      pages = {283--299}
    }
    					
    Houlahan1992 Houlahan, J.; Marcus, W.A. & Shirmohammadi, A. Estimating Maryland critical area acts impact on future nonpoint pollution along the Rhode River estuary 1992 Water Resources Bulletin
    Vol. 28 (3) , pp. 553-567  
    article
    Abstract: This paper presents the results of an investigation of the effects
    of the Maryland Critical Area Act on generation of nonpoint source
    loads of phosphorus, nitrogen, and sediment to the Rhode River estuary.
    The Simple Method model, the Marcus and Kearney regression model,
    and the CREAMS model were used to estimate annual loads under: (1)
    present conditions, (2) maximum land use development allowable under
    the Act, and (3) two sets of future land use conditions that might
    occur if the Act were not in place. Results indicate that the Critical
    Area Act can reduce the present generation of nonpoint nutrient and
    sediment loadings 20-30 percent from the regulated area. These reductions
    can occur while preserving agricultural lands and allowing limited
    residential and urban development. The decrease in nutrient loadings
    is primarily dependent upon implementation and enforcement of agricultural
    best management practices (BMPs). The BMPs could reduce present agricultural
    nutrient loadings by 90 percent to a level comparable to loadings
    from residential areas. The estimated effectiveness of the Critical
    Area Act is even greater when compared to potential future nutrient
    loadings if development in the area remains unregulated. Unrestricted
    residential and urban development could increase nutrient loadings
    by 200 percent to 1000 percent as compared to controlled development
    under Critical Area Act guidelines.The Critical Area Act primarily
    prevents these future increases by severely limiting woodland cutting,
    with lesser results obtained by requiring urban BMPs.
    BibTeX:
    @article{Houlahan1992,
      author = {Houlahan, J and Marcus, WA and Shirmohammadi, A},
      title = {Estimating Maryland critical area acts impact on future nonpoint pollution along the Rhode River estuary},
      journal = {Water Resources Bulletin},
      year = {1992},
      volume = {28},
      number = {3},
      pages = {553--567}
    }
    					
    Marcus1992 Marcus, W.A.; Roberts, K.; Harvey, L. & Tackman, G. An evaluation of methods for estimating Mannings-n in small mountain streams 1992 Mountain Research and Development
    Vol. 12 (3) , pp. 227-239  
    article fluvial geomorphology
    Abstract: This article evaluates eleven techniques for estimating Manning's
    roughness coefficient in a small mountain stream (hydraulic radius
    less than 0.25 m). Observed roughness values at 15 sites were very
    high compared to lower gradient streams, ranging from 0.056 to 0.183.
    Jarrett's (1984) technique produced the best estimates of Manning's
    n, although it overestimated roughness by an average of 32% in the
    steep, turbulent flow. The other ten estimation methods significantly
    under predicted Manning's n, often by an order of magnitude. The
    underestimates occur because the methods do not adequately address
    the effects on flow resistance of large sediment sizes, low ratios
    of flow depth to hydraulic radius, steep slopes, and severe turbulence.
    In addition, observers using subjective visual estimation techniques
    underestimated roughness because of their training in lowland settings.
    The poor performance of the estimation techniques suggests that discharge
    should be measured directly whenever possible in steep mountain streams,
    particularly when determining discharges at low flows where a significant
    portion of the bed sediments are near to or are breaking the water
    surface. If one must use roughness estimates to calculate discharge
    in a small mountain stream, then the Jarrett (1984) method provides
    the most reasonable estimates of resistance to flow, although care
    should be taken to avoid reaches with plunge pool sequences and hydraulic
    jumps.
    BibTeX:
    @article{Marcus1992,
      author = {Marcus, WA and Roberts, K and Harvey, L and Tackman, G},
      title = {An evaluation of methods for estimating Mannings-n in small mountain streams},
      journal = {Mountain Research and Development},
      year = {1992},
      volume = {12},
      number = {3},
      pages = {227--239}
    }
    					
    Solomon1992 Solomon, A.M. & Bartlein, P.J. Past and future climate change - response by mixed deciduous coniferous forest ecosystems in northern Michigan 1992 Canadian Journal of Forest Research
    Vol. 22 (11) , pp. 1727-1738  
    article
    Abstract: During the 21st century, global climate change is expected to become
    a significant force redefining global biospheric boundaries and vegetation
    dynamics. In the northern hardwood - boreal forest transition forests,
    it should, at the least, control reproductive success and failure
    among unmanaged mixed forest stands. One means by which to predict
    future responses by the mixed forests is to examine the way in which
    they have responded to climate changes in the past. We used proxy
    climate data derived from Holocene (past 10 000 years) pollen records
    in the western Upper Peninsula of Michigan to drive forest gap models,
    in an effort to define regional prehistoric vegetation dynamics on
    differing soils. The gap models mimic forest reproduction and growth
    as a successional process and, hence, are appropriate for defining
    long-term tree and stand dynamics. The modeled period included a
    mid-postglacial period that was warmer than today's climate. Model
    failures, made apparent from the exercise, were corrected and the
    simulations were repeated until the model behaved credibly. Then,
    the same gap model was used to simulate potential future vegetation
    dynamics, driven by projections of a future climate that was controlled
    by greenhouse gases. This provided us with the same "measure" of
    vegetation in the past, present, and future, generating a continuously
    comparable record of change and stability in forest composition and
    density. The resulting projections of vegetation response to climate
    change appear to be affected more by the rate than by the magnitude
    of climate change.
    BibTeX:
    @article{Solomon1992,
      author = {Solomon, AM and Bartlein, PJ},
      title = {Past and future climate change - response by mixed deciduous coniferous forest ecosystems in northern Michigan},
      journal = {Canadian Journal of Forest Research},
      year = {1992},
      volume = {22},
      number = {11},
      pages = {1727--1738}
    }
    					
    Webb1992 Webb, T. & Bartlein, P.J. Global changes during the last 3 million years - climatic controls and biotic responses 1992 Annual Review of Ecology and Systematics
    Vol. 23 , pp. 141-173  
    article
    BibTeX:
    @article{Webb1992,
      author = {Webb, T and Bartlein, PJ},
      title = {Global changes during the last 3 million years - climatic controls and biotic responses},
      journal = {Annual Review of Ecology and Systematics},
      year = {1992},
      volume = {23},
      pages = {141--173}
    }
    					
    Anderson1991 Anderson, P.M.; Bartlein, P.J.; Brubaker, L.B.; Gajewski, K. & Ritchie, J.C. Vegetation-pollen-climate relationships for the arcto-boreal region of North America and Greenland 1991 Journal of Biogeography
    Vol. 18 (5) , pp. 565-582  
    article
    Abstract: We examine modern pollen, vegetation and climate relationships for
    the arcto-boreal region of North America using isopollen maps, scatter
    diagrams and response surfaces. These analyses are based on an array
    of 1119 modern pollen sites extending from Alaska to Greenland (excluding
    the Pacific-Cordillera region of western North America) and north
    of 42-degrees-N latitude. The pollen sum consists of thirty-one taxa
    selected for their abundance on the modern landscape or significance
    as indicators of particular vegetation types. Response surfaces were
    calculated using a locally weighted-average procedure in order to
    display the percentages of the various taxa as a function of one
    to three climate variables. The isopoll maps accurately reflect taxa
    abundance and range limits, although the actual percentage at these
    limits may vary. Pollen of the major boreal taxa have optima at 10-20-degrees-C
    and dry (Pinus), moist (Abies) and intermediate (Picea) values of
    precipitation. Monospecific pollen taxa and those where the species
    have similar ecologies show a simple climate optimum, whereas pollen
    taxa with several species, such as Betula, show multiple optima.
    Each boreal taxon, even those with similar ranges, has a unique surface,
    suggesting that community level responses to climatic change, whether
    past or future, are likely to be complex and variable throughout
    North America.
    BibTeX:
    @article{Anderson1991,
      author = {Anderson, PM and Bartlein, PJ and Brubaker, LB and Gajewski, K and Ritchie, JC},
      title = {Vegetation-pollen-climate relationships for the arcto-boreal region of North America and Greenland},
      journal = {Journal of Biogeography},
      year = {1991},
      volume = {18},
      number = {5},
      pages = {565--582}
    }
    					
    Edwards1991 Edwards, M.E. & McDowell, P.F. Interglacial deposits at Birch Creek, northeast interior Alaska 1991 Quaternary Research
    Vol. 35 (1) , pp. 41-52  
    article
    BibTeX:
    @article{Edwards1991,
      author = {Edwards, ME and McDowell, PF},
      title = {Interglacial deposits at Birch Creek, northeast interior Alaska},
      journal = {Quaternary Research},
      year = {1991},
      volume = {35},
      number = {1},
      pages = {41--52}
    }
    					
    Marcus1991 Marcus, W.A. & Kearney, M.S. Upland and coastal sediment sources in a Chesapeake Bay estuary 1991 Annals of the Association of American Geographers
    Vol. 81 (3) , pp. 408-424  
    article
    BibTeX:
    @article{Marcus1991,
      author = {Marcus, WA and Kearney, MS},
      title = {Upland and coastal sediment sources in a Chesapeake Bay estuary},
      journal = {Annals of the Association of American Geographers},
      year = {1991},
      volume = {81},
      number = {3},
      pages = {408--424}
    }
    					
    Overpeck1991 Overpeck, J.T.; Bartlein, P.J. & Webb, T. Potential magnitude of future vegetation change in eastern North America - comparisons with the past 1991 Science
    Vol. 254 (5032) , pp. 692-695  
    article
    Abstract: Increases in atmospheric trace gas concentrations could warm the global
    average temperature 1.5-degrees to 4.5-degrees-C by the end of the
    next century. Application of climate-pollen response surfaces to
    three climate model simulations of doubled preindustrial atmospheric
    CO2 levels shows that the change in the equilibrium distribution
    of natural vegetation over eastern North America over the next 200
    to 500 years could be larger than the overall change during the past
    7,000 to 10,000 years and equivalent to the change that took place
    over the 1,000- to 3,000-year period of most rapid deglaciation.
    Some plant ranges and abundance maxima could shift as much as 500
    to 1000 km during the next 200 to 500 years; such changes would have
    dramatic impacts on silvicultural and natural ecosystems. Although
    unprecedented vegetation change is likely if climate changes as predicted,
    forecasting the exact timing and patterns of change will be difficult.
    BibTeX:
    @article{Overpeck1991,
      author = {Overpeck, JT and Bartlein, PJ and Webb, T},
      title = {Potential magnitude of future vegetation change in eastern North America - comparisons with the past},
      journal = {Science},
      year = {1991},
      volume = {254},
      number = {5032},
      pages = {692--695}
    }
    					
    Prentice1991 Prentice, I.C.; Bartlein, P.J. & Webb, T. Vegetation and climate change in eastern North America since the last glacial maximum 1991 Ecology
    Vol. 72 (6) , pp. 2038-2056  
    article
    Abstract: Response surfaces describing the empirical dependence of surface pollen
    percentages of 13 taxa on three standard climatic variables (mean
    July temperature, mean January temperature, and mean annual precipitation)
    in eastern North America were used to infer past climates from palynological
    data. Inferred climates at 3000-yr intervals from 18 000 years ago
    to the present, based on six taxa (spruce, birch, northern pines,
    oak, southern pines, and prairie forbs), were used to generate time
    series of simulated isopoll maps for these taxa and seven others
    (hickory, fir, beech, hemlock, elm, alder, and sedge). The simulations
    captured the essential features of the observed isopoll maps for
    both sets of taxa, including differences in migration patterns during
    the past 10000 yr that have previously been attributed to differential
    migration lag. These results establish that the continental-scale
    vegetation patterns have responded to continuous changes in climate
    from the last glacial maximum to the present, with lags less-than-or-equal-to
    1500 yr. The inferred climatic changes include seasonality changes
    consistent with orbitally controlled changes in insolation, and shifts
    in temperature and moisture gradients that are consistent with modelled
    climatic interactions of the insolation changes with the shrinking
    Laurentide ice sheet. These results pose new ecological questions
    about the processes by which vegetated landscapes approach dynamic
    equilibrium with their changing environment.
    BibTeX:
    @article{Prentice1991,
      author = {Prentice, IC and Bartlein, PJ and Webb, T},
      title = {Vegetation and climate change in eastern North America since the last glacial maximum},
      journal = {Ecology},
      year = {1991},
      volume = {72},
      number = {6},
      pages = {2038--2056}
    }
    					
    Hostetler1990 Hostetler, S.W. & Bartlein, P.J. Simulation of lake evaporation with application to modeling lake level variations of Harney-Malheur Lake, Oregon 1990 Water Resources Research
    Vol. 26 (10) , pp. 2603-2612  
    article
    BibTeX:
    @article{Hostetler1990,
      author = {Hostetler, SW and Bartlein, PJ},
      title = {Simulation of lake evaporation with application to modeling lake level variations of Harney-Malheur Lake, Oregon},
      journal = {Water Resources Research},
      year = {1990},
      volume = {26},
      number = {10},
      pages = {2603--2612}
    }
    					
    Anderson1989 Anderson, P.M.; Bartlein, P.J.; Brubaker, L.B.; Gajewski, K. & Ritchie, J.C. Modern analogs of Late Quaternary pollen spectra from the western interior of North America 1989 Journal of Biogeography
    Vol. 16 (6) , pp. 573-596  
    article modern analogues
    BibTeX:
    @article{Anderson1989,
      author = {Anderson, PM and Bartlein, PJ and Brubaker, LB and Gajewski, K and Ritchie, JC},
      title = {Modern analogs of Late Quaternary pollen spectra from the western interior of North America},
      journal = {Journal of Biogeography},
      year = {1989},
      volume = {16},
      number = {6},
      pages = {573--596}
    }
    					
    Bartlein1989 Bartlein, P.J. & Prentice, I.C. Orbital variations, climate and paleoecology 1989 Trends in Ecology & Evolution
    Vol. 4 (7) , pp. 195-199  
    article
    BibTeX:
    @article{Bartlein1989,
      author = {Bartlein, PJ and Prentice, IC},
      title = {Orbital variations, climate and paleoecology},
      journal = {Trends in Ecology & Evolution},
      year = {1989},
      volume = {4},
      number = {7},
      pages = {195--199}
    }
    					
    Huntley1989 Huntley, B.; Bartlein, P.J. & PRENTICE, I.C. Climatic control of the distribution and abundance of beech (Fagus L) in Europe and North America 1989 Journal of Biogeography
    Vol. 16 (6) , pp. 551-560  
    article vegetation and climate
    BibTeX:
    @article{Huntley1989,
      author = {Huntley, B and Bartlein, PJ and PRENTICE, IC},
      title = {Climatic control of the distribution and abundance of beech (Fagus L) in Europe and North America},
      journal = {Journal of Biogeography},
      year = {1989},
      volume = {16},
      number = {6},
      pages = {551--560}
    }
    					
    Marcus1989 Marcus, W.A. Dilution mixing estimates of trace-metal concentrations in suspended sediments 1989 Environmental Geology and Water Sciences
    Vol. 14 (3) , pp. 213-219  
    article
    BibTeX:
    @article{Marcus1989,
      author = {Marcus, WA},
      title = {Dilution mixing estimates of trace-metal concentrations in suspended sediments},
      journal = {Environmental Geology and Water Sciences},
      year = {1989},
      volume = {14},
      number = {3},
      pages = {213--219}
    }
    					
    Marcus1989a Marcus, W.A. Lag-time routing of suspended sediment concentrations during unsteady-flow 1989 Geological Society of America Bulletin
    Vol. 101 (5) , pp. 644-651  
    article
    BibTeX:
    @article{Marcus1989a,
      author = {Marcus, WA},
      title = {Lag-time routing of suspended sediment concentrations during unsteady-flow},
      journal = {Geological Society of America Bulletin},
      year = {1989},
      volume = {101},
      number = {5},
      pages = {644--651}
    }
    					
    Marcus1989b Marcus, W.A. Regulating contaminated sediments in aquatic environments - a hydrologic perspective 1989 Environmental Management
    Vol. 13 (6) , pp. 703-713  
    article
    BibTeX:
    @article{Marcus1989b,
      author = {Marcus, WA},
      title = {Regulating contaminated sediments in aquatic environments - a hydrologic perspective},
      journal = {Environmental Management},
      year = {1989},
      volume = {13},
      number = {6},
      pages = {703--713}
    }
    					
    Marcus1987 Marcus, W.A. Copper dispersion in ephemeral stream sediments 1987 Earth Surface Processes and Landforms
    Vol. 12 (3) , pp. 217-228  
    article
    BibTeX:
    @article{Marcus1987,
      author = {Marcus, WA},
      title = {Copper dispersion in ephemeral stream sediments},
      journal = {Earth Surface Processes and Landforms},
      year = {1987},
      volume = {12},
      number = {3},
      pages = {217--228}
    }
    					
    Bartlein1986 Bartlein, P.J.; Prentice, I.C. & Webb, T. Climatic response surfaces from pollen data for some eastern North American taxa 1986 Journal of Biogeography
    Vol. 13 (1) , pp. 35-57  
    article vegetation and climate and pollen
    BibTeX:
    @article{Bartlein1986,
      author = {Bartlein, PJ and Prentice, IC and Webb, T},
      title = {Climatic response surfaces from pollen data for some eastern North American taxa},
      journal = {Journal of Biogeography},
      year = {1986},
      volume = {13},
      number = {1},
      pages = {35--57}
    }
    					
    Bartlein1984 Bartlein, P.J.; Webb, T. & Fleri, E. Holocene climatic-change in the northern midwest - pollen-derived estimates 1984 Quaternary Research
    Vol. 22 (3) , pp. 361-374  
    article
    BibTeX:
    @article{Bartlein1984,
      author = {Bartlein, PJ and Webb, T and Fleri, E},
      title = {Holocene climatic-change in the northern midwest - pollen-derived estimates},
      journal = {Quaternary Research},
      year = {1984},
      volume = {22},
      number = {3},
      pages = {361--374}
    }
    					
    McDowell1983 McDowell, P.F. Evidence of stream response to Holocene climatic change in a small Wisconsin watershed 1983 Quaternary Research
    Vol. 19 (1) , pp. 100-116  
    article
    BibTeX:
    @article{McDowell1983,
      author = {McDowell, PF},
      title = {Evidence of stream response to Holocene climatic change in a small Wisconsin watershed},
      journal = {Quaternary Research},
      year = {1983},
      volume = {19},
      number = {1},
      pages = {100--116}
    }
    					
    Bartlein1982 Bartlein, P.J. Streamflow anomaly patterns in the USA and southern Canada - 1951-1970 1982 Journal of Hydrology
    Vol. 57 (1-2) , pp. 49-63  
    article
    BibTeX:
    @article{Bartlein1982,
      author = {Bartlein, PJ},
      title = {Streamflow anomaly patterns in the USA and southern Canada - 1951-1970},
      journal = {Journal of Hydrology},
      year = {1982},
      volume = {57},
      number = {1-2},
      pages = {49--63}
    }
    					

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