Forecasting forest response to N deposition: integrating data from individual plant responses to soil chemistry with a continental-scale gradient analysis

Nitrogen deposition is altering forest dynamics, terrestrial carbon storage, and biodiversity. However, our ability to forecast how different tree species will respond to N deposition, especially key response thresholds, is limited by a lack of synthesis across spatial scales and research approaches. To develop our best understanding of N deposition impact on tree growth and survival, we will integrate plot-­‐ level studies describing plant growth and survival responses to N inputs and plant-­‐ available soil nutrients with a continental scale analysis across a N deposition gradient. Our primary outcome will be estimates of tree response to N deposition with explicit representation of uncertainty and the identification...

Categories: Project; Tags: Active, All Working Groups, Ecosystems, Land Resources, Nitrogen, All tags... Plants, Soil, Fewer tags

Novel multi‐scale synthesis of nitrogen fixation rates and drivers across the terrestrial biosphere

Biological nitrogen fixation (BNF) is a critical biogeochemical process that converts inert atmospheric N2 gas into biologically usable forms of the essential nutrient nitrogen. A variety of free-living and symbiotic organisms carry out BNF, and in most regions worldwide, BNF is the largest source of nitrogen that fuels terrestrial ecosystems. As a result, BNF has far reaching effects on ecosystem properties (water quality, carbon storage), sustainability (plant growth, soil fertility), and the global climate system. Despite this cross-cutting importance, existing syntheses of BNF have major gaps, with particular challenges in upscaling local measurements across large areas. These gaps, and a corresponding lack...

Categories: Project; Tags: Active, All Working Groups, Ecosystems, Land Resources, Nitrogen

Evidence for shifts in plant species diversity along N deposition gradients: a first synthesis for the United States

The impacts of nitrogen (N) deposition on plant diversity loss have been well documented across N deposition gradients in Europe, but much less so in the U.S. Published N fertilizer studies suggest losses will occur in the US, but many of these were done at levels of N input that were higher than modeled and measured N deposition, and higher than presumed N critical loads. The recent availability of modeled N deposition across the U.S. (e.g. using CMAQ) has provided a high‐resolution tool to identify regions where steep N deposition gradients facilitate detection of ecological shifts. A number of plant diversity (richness plus abundance) data sets across the U.S. have explained diversity shifts based on anthropogenic...

Categories: Project; Tags: Active, All Working Groups, Ecosystems, Land Resources, Nitrogen, All tags... Plants, Synthesis, Fewer tags

System analysis of land use and climate effects on ecosystem services affecting C and N exchanges with the atmosphere and water cycles

Current land use practices have affected ecosystem structure and processes in ways that have degraded delivery of key ecosystem services controlling exchanges of carbon and nitrogen with the atmosphere and surface and groundwater systems. These impacts are observed in the emissions of greenhouse gases (GHG) and N pollution in our nation’s water systems and coastal areas. Improvements in databases of climate, soils, and land use practices in the north central Great Plains (i.e., NCGP: Colorado, Kansas, Wyoming, Nebraska, Montana, South Dakota, and North Dakota) provide a unique opportunity for integration and synthesis of this information on the exchanges of C and N affecting our environmental resources. In addition,...

Categories: Data, Project; Types: Downloadable, GeoTIFF, Map Service, Raster; Tags: All Working Groups, Atmosphere, Carbon, Completed, Ecosystems, All tags... Ecosystems, Land Resources, Nitrogen, water cycle, Fewer tags