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Laurent, Ed
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Expertise Search
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Lee, Danny
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Danny is Director of the Eastern Forest Environmental Threat Assessment Center of the USDA Forest Service's Southern Research Station in Asheville, NC. He lead a diverse team of reearchers working to develop tools and information needed to detect, assess, and predict environmental treats to eastern forests.
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Expertise Search
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Novel climates, no-analog communities, and ecological surprises
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No-analog communities (communities that are compositionally unlike any found today) occurred frequently in the past and will develop in the greenhouse world of the future. The well documented no-analog plant communities of late-glacial North America are closely linked to “novel” climates also lacking modern analogs, characterized by high seasonality of temperature. In climate simulations for the Intergovernmental Panel on Climate Change A2 and B1 emission scenarios, novel climates arise by 2100 AD, primarily in tropical and subtropical regions. These future novel climates are warmer than any present climates globally, with spatially variable shifts in precipitation, and increase the risk of species reshuffling into future no-analog communities and other ecological surprises. Most ecological models are at least partially parameterized from modern observations and so may fail to accurately predict ecological responses to these novel climates. There is an urgent need to test the robustness of ecological models to climate conditions outside modern experience.
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Resources
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Climate Science Documents
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Palaeodata-informed modelling of large carbon losses from recent burning of boreal forests
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Wildfires play a key role in the boreal forest carbon cycle(1,2), and models suggest that accelerated burning will increase boreal C emissions in the coming century (3). However, these predictions may be compromised because brief observational records provide limited constraints to model initial conditions (4). We confronted this limitation by using palaeoenvironmental data to drive simulations of long-term C dynamics in the Alaskan bo- real forest. Results show that fire was the dominant control on C cycling over the past millennium, with changes in fire frequency accounting for 84% of C stock variability. A recent rise in fire frequency inferred from the palaeorecord5 led to simulated C losses of 1.4 kg C m?2(12% of ecosystem C stocks) from 1950 to 2006. In stark contrast, a small net C sink of 0.3 kg C m?2 occurred if the past fire regime was assumed to be similar to the modern regime, as is common in models of C dynamics. Although boreal fire regimes are heterogeneous, recent trends6 and future projections (7) point to increasing fire activity in response to climate warming throughout the biome. Thus, predictions (8) that terrestrial C sinks of northern high latitudes will mitigate rising atmospheric CO2 may be over-optimistic.
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Resources
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Climate Science Documents
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Predicting a change in the order of spring phenology in temperate forests
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The rise in spring temperatures over the past half-century has led to advances in the phenology of many nontropical plants and animals. As species and populations differ in their phenological responses to temperature, an increase in temperatures has the potential to alter timing-dependent species interactions. One species-interaction that may be affected is the competition for light in deciduous forests, where early vernal species have a narrow window of opportunity for growth before late spring species cast shade. Here we consider the Marsham phenology time series of first leafing dates of thirteen tree species and flowering dates of one ground flora species, which spans two centuries. The exceptional length of this time series permits a rare comparison of the statistical support for parameter-rich regression and mechanistic thermal sensitivity phenology models. While mechanistic models perform best in the majority of cases, both they and the regression models provide remarkably consistent insights into the relative sensitivity of each species to forcing and chilling effects. All species are sensitive to spring forcing, but we also find that vernal and
northern European species are responsive to cold temperatures in the previous autumn. Whether this sensitivity reflects a chilling requirement or a delaying of dormancy remains to be tested. We then apply the models to projected future temperature data under a fossil fuel intensive emissions scenario and predict that while some species will advance substantially others will advance by less and may even be delayed due to a rise in autumn and winter temperatures. Considering the projected responses of all fourteen species, we anticipate a change in the order of spring events, which may lead to changes in competitive advantage for light with potential implications for the composition of temperate forests.
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Resources
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Climate Science Documents
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Reviewing Existing Tools and Data on Hydrologic and Ecologic Flow Models
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The Aquatic Ecological Flows project reviewed existing tools and gathered available data within the project area on hydrologic and ecological flow models that would be suitable to use for the region.
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News & Events
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Reviewing Studies of Caves and Subterranean Biodiversity
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A status review of studies from the cave and karst classification and mapping research project examined an array of research regarding cave environments, cave/karst biodiversity, and previous techniques for mapping and modeling such ecosystems.
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News & Events
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Scott Robinson: Southeast Aquatic Resources Partnership
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Coordinator Scott Robinson addresses the obstacles of data collection, preparation, and development and how the LCCs can help standardized this process for all partners to use that will help professionals implement conservation actions.
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Our Community
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Voices from the Community
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Stream Impacts from Water Withdrawals Phase 1 Report
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The 1st phase of this research project involved reviewing existing tools and gathering available data within the project area on hydrologic and ecological flow model(s) that would be suitable for the region.
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Research
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Funded Projects
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Stream Impacts from Water Withdrawals in the Marcellus Shale Region
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Synthesis of climate model downscaling products for the southeastern United States
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Downscaling translates large-scale climate information to the local scale. There are several techniques for handling this process; recently, several downscaled climate products have been produced by government and academic researchers. Ecologists, conservation scientists, and practitioners require such local guidance to evaluate adaptation and conservation strategies. However, the large number of methods involved, different downscaling approaches, resolutions, time periods, and focal variables limits the ability of these users to form meaningful conclusions and evaluate the results of adaptation strategies. To address these issues, this project will summarize the methods used for downscaling, identify the metrics most appropriate for evaluation of climate model skill and usability for the ecological and conservation communities in the southeastern US, and begin a longer-term effort to evaluate the range of downscaled climate products over this geographic region.
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Research
