Comparative Effects of Global Climate on Ecosystem Nitrogen and Soil Biogeochemistry in the U.S. National Parks

Current long-term global climate (GC) change research combined with watershed studies meet DOI Secretarial, NPS and USGS priorities. Long-term biogeochemical monitoring coupled with ecosystem process research provides essential information to address current DOI and other land conservation issues. Information from long-term study of parks is key to understanding the effects of human activity on ecosystem processes. Long-term GC and watershed studies implemented by the NPS in collaboration with USGS, FORT are expanding our knowledge about the response of natural systems to stress, the sources of stress, climate, biota and soils interactions, aquatic and terrestrial biogeochemical cycles, especially nitrogen (N) and sulfur (S), and, surface water chemistry, biology, and hydrology. We now propose to employ these long-term data sets to test hypotheses regarding ecosystem response to N over a wide range of climatic (temperature and moisture) conditions at 5 National Parks national parks. Work is to be conducted in forests, montane, and arid/semi-arid areas to assess biogeochemical cycling, watershed response, and hydrology. Our concept in this proposal addresses multi-regional issues affecting the integrity of "natural" ecosystems. We ask basic questions of ecosystem function, in especially sensitive sites, and how the effects of atmospheric contaminant inputs, particularly inorganic N, coupled with shifts in temperature and/or moisture can affect species invasions and biodiversity. Nitrogen is the most pervasive limiting nutrient in terrestrial ecosystems. However, there is a high potential for present atmospheric inputs of N to be significantly augmented by mineral N release from soil organic matter pools with a slight gain in temperature and/or moisture. Once this process is initiated, in time it will lead to marked change in ecosystem biodiversity both above- and below-ground. Such ecosystem stress will be chronic, subtle, and very widespread making tactical mitigation, as through local management, nearly impossible. To anticipate effects before they are widespread requires a conceptual research approach with high potential to statistically detect incipient change and assess its magnitude in the ecosystem. Specific short-term (5 year) objectives are:

1) quantify long-term change in hydrologic, nutrient, and C budgets on a gradient of watershed ecosystem biota,

3) examine spatial and temporal change in subsurface soil water chemistry and flow to quantify N export and response to change in soil temperature and moisture,

4) examine how changes in soil N availability alters forest floor and soil production of dissolved organic carbon (DOC) and dissolved organic nitrogen,

5) quantify change in labile C and N compounds from microbial biomass in response to soil temperature and N availability,

6) evaluate long-term trends in forest floor and soil microbial activity, soil microbial biomass and functional diversity, and provide biological parameters for measuring ecosystem stability and response to disturbance,

7) assess spatial and temporal patterns in decomposition rates as decomposition of plant litter is a key ecosystem process linking the below-ground microbial component with primary ecosystem production,

8) assess impact of changes in forest structure alone and in combination with environmental changes (atmospheric inputs, global climate) on the function of forested watersheds (biogeochemistry and nutrient retention), and,

9) provide management recommendations concerning human impacts on Park watersheds.

Principal Investigator(s)

Herrmann, Ray
Zak, John
Urbanczyk, Kevin
Stottlemyer, Robert
Binkley, Dan
Edmonds, Robert
Marra, James
Murray, Geogia
Fagre, Dan
Van Miegroet, Helga
Nicholas, Niki
Tarboton, David
Solomon, Kip
Creed, Irena
Moore, Steve

Comparative Effects of Global Climate on Ecosystem Nitrogen and Soil Biogeochemistry in the U.S. National Parks

Project Description

Principal Investigator(s)