Multifactor classification of forest landscape ecosystems of Jocassee Gorges, southern Appalachian Mountains, South Carolina

Abstract

Ecosystem classification identifies interrelationships within and among the geomorphology, soils, and vegetation that converge to form ecosystems across forest landscapes. We developed a multifactor ecosystem classification system for a 13 000 ha southern Appalachian landscape acquired in 1998 by the South Carolina Department of Natural Resources. Using a combination of multivariate analyses, we distinguished five ecosystem types ranging from xeric oak (Quercus spp.) to mesic eastern hemlock (Tsuga canadensis (L.) Carrière) ecosystems. Ecosystems segregated along geomorphic gradients influencing potential moisture availability, with soil properties such as solum thickness distinguishing among ecosystems occupying similar topographic positions. Our results suggest that different combinations of geomorphic and soil factors interact to form similar ecosystems across the landscape, and a given environmental factor can impact ecosystem development at some constituent sites of an ecosystem type but not at other sites. A regional comparison of ecosystem classifications indicates that environmental variables important for distinguishing ecosystems in the southern Appalachians vary, with Jocassee Gorges characterized by unique suites of environmental complexes. Our study supports the contention that the strengths of ecosystem classification are providing (i) comprehensive information on the interrelationships among ecosystem components, (ii) a foundation from which to develop ecologically based forest management plans, and (iii) an ecological framework in which to conduct future research on specific ecosystem components or processes.