Long-term Studies of Ecosystem Response to Disturbance Along Environmental Gradients at Coweeta Hydrologic Laboratory

This project will continue long-term studies of response and recovery of Southern Appalachian forested ecosystems to disturbances. To understand and predict responses to current and emerging environmental problems requires an expansion of research perspective from a watershed to a landscape. The project will emphasize new studies along a complex environmental gradient with a continued emphasis on use of experimental manipulation to examine ecosystem response to disturbance. An elevational sequence that represents a gradient in external driving variables (e.g. temperature, precipitation) as well as a gradient in ecosystem response will be used in this study. Three interconnected ecosystems are arrayed along this response gradient: forested slopes, riparian zone and stream. The PIs will test the following ideas in these landscape components: (1) Forest structure and processes in the Southern Appalachians are currently changing as a result of both historic factors and recent drought-induced tree mortality. (2) Differences in structural and functional characteristics of stream ecosystems along elevational and longitudinal gradients are a consequence of changes in the relative abundance of geomorphic patch types along the stream. (3) Rhododendron maximum is a keystone species in the Southern Appalachian landscape, regulating the rates of soluble and particulate element export from the forest and reducing stream productivity. This is an outstanding research group that is recognized at the national and international level as leaders in the area of forest ecosystem research. Institutional support is excellent and the project management is dynamic and effect. Coweeta Hydrologic Laboratory has been the site of interdisciplinary ecological research for over twenty years. This is an exceptional Long-Term Ecological Research (LTER) project.//