1994 LTER SITE AUGMENTATION AWARDS--PROPOSAL SUMMARIES Coweeta Hydrologic Laboratory & North Temperate Lakes - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Long-Term Studies of Ecosystem Response to Disturbance Along Environmental Gradients at Coweeta Hydrologic Laboratory Judith L. Meyer $499,959, 24 months Our goal is to develop a predictive understanding of the social, economic, and environmental factors that drive land cover change in the Southern Appalachians and the ecological consequences of those changes in landscape pattern for regional C cycles and for terrestrial and aquatic biodiversity. We will do this with an integrated program that recognizes humans as an integral part of the Southern Appalachian landscape. We combine the long-term perspective of change in the vegetation and in C stores since the Pleistocene with recent changes in land cover and modeling of human decisions regarding land use to understand past and likely future drivers of change sin landscape pattern in the region. We consider the effects of these landscape changes on regional C storage and rates of flux and on the biota of a region that is characterized by high biodiversity. The proposed research has six specific objectives: 1. Understand the role of fire in governing vegetation and C cycling changes in the Southern Appalachians since the late Pleistocene; 2. Document the history of land cover change in the region during the past 50 years; 3. Identify and model economic and social factors structuring landscape pattern; 4. Document and model the ecological consequences of land cover change for regional C pools and fluxes; 5. Predict effects of land cover change on native tree, herb, and bird assemblages; and 6. On assemblages of stream benthic invertebrates and fishes. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LTER: Comparative Studies of a Suite of Lakes in Wisconsin John J. Magnuson $498,906, 24 months Inland lakes are important features of the Upper Great Lakes region of North America. As collectors of water, solutes, and pollutants from overland or groundwater flow, as habitat for aquatic biota, and as attractors of human activities, lakes both affect and are affected by natural and human-induced changes in the regional landscape. The work proposed here will scale up the North Temperate Lakes Long-Term Ecological Research project to address the regional feedbacks that link lakes, landscapes, and human activity. Two primary objectives of the proposed research are to determine (1) whether and how dominant factors controlling lake ecosystems vary systematically as spatial scales expand from individual lakes, to watershed, to lake districts, to the Upper Great Lakes region, and temporal scales extend from years, to decades, to centuries; and (2) how natural and human-induced changes in the landscape have interacted with aquatic ecosystem structure and dynamics in the Upper Great Lakes Region over the past two centuries, and what changes can be expected over the next hundred years. These objectives will be accomplished using several approaches. First, regional studies at a range of spatial scales will be used to determine large scale patterns and generality of smaller scale results. These studies will involve scientists and data from three other lake districts in the Upper Great Lakes region: the agricultural and urban catchments near Madison, Wisconsin; the Experimental Lakes Area of western Ontario; and the Dorset Research Area of eastern Ontario. Second, comprehensive site histories will be developed to evaluate past interactions between land use changes and inland lakes. These histories will include archived data and paleolimnological work coupled with detailed histories of land use in the lake districts. Finally, alternative scenarios for future land use-lake interactions will be developed and tested through cooperation of natural and social scientists. The work will be grounded in ecology, limnology, geology and water chemistry, but the context and feedbacks will be relevant to issues of conservation, economic development, sustainability, and ecosystem management. The generality of key results from individual lake districts will be tested in other lake districts within the region. Specific issues for the next two years include the importance of landscape position in influencing lake dynamics, cyclic patterns of water clarity in lakes with simple fish communities, the utility of stable isotopes for assessing water balances, and the potential impact of a generally warming climate on inland lakes. Models linking landscapes and lakes will also be developed. In the northern parts of the region major landscape changes have been associated with clearcutting of forests, subsequent regrowth, and increased development of seasonal and permanent houses on lake shorelines. Consequently, spatially explicit models linking water flow to lakes and biogeochemical cycling of forest ecosystems will be developed to determine potential impacts of various scenarios of changing climate and forestry practices on lakes. In the south, major changes have been transformation of savanna to agriculture and urban uses. Models linking surface flows to phosphorus input to lakes will be developed to test effects of alternative management scenarios. Collectively, the understanding of landscape-lake-human interactions built by this study will be directly relevant to those making policies affecting the future of the Upper Great Lakes region. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - The full proposal is posted on the North Temperate Lakes LTER site Web page at http://limnosun.limnology.wisc.edu/augmentation_proposal/