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Past Research 1996-2002 P-IIA: Disturbance history, land-use, and impacts on biodiversity at various spatial scales Summary: Using a combination of field and modeling studies, we are investigating the interaction between life-history strategies and habitat fragmentation that affect species diversity and abundances. The importance of human land-use for explaining the patterns of biotic diversity observed in today's landscapes has been recognized recently. The field studies we initiated in 1995 focused on only the fragmentation of native habitats into smaller patches, and their effects on vascular plants and breeding birds in mesic cove forests. Two other factors are likely to explain substantial variability in the plant and animal communities. First, even within small forest fragments, the natural sources of environmental heterogeneity are important. Second, the past use(s) of the forest (e.g. logging, agriculture, pasture) or the occurrence of natural disturbances appear to have a strong influence on both biotic and abiotic components of the environment at a variety of spatial scales. By continuing our studies of the effects of land-use on the native biota and expanding our work to other taxa (arthropods, mammals and salamanders), we are able to explore the mechanisms underlying the effects of habitat fragmentation and land-use on the plant communities. Our study addresses four questions: 1) How does the legacy of land-use affect community composition in forest patches? 2) Do land-use practices change the spatial scale of heterogeneity of the biota within forest patches as compared to undisturbed forest patches? 3) In forest fragments, how do within and between-patch heterogeneity interact with species life-history traits to determine presence and abundance of forest herbs? 4) How does species abundance and diversity vary in naturally occurring patches in relatively undisturbed portions of the forest landscape? An essential complement to our field studies is the development of spatially-explicit models of how populations respond to landscape-scale habitat changes. We have already developed rule-based models that describe the spatial distribution of suitable habitat across the landscape for individual species. A model developed under current funding integrates species' life-history characteristics in a spatial context to permit dynamic simulation of populations across heterogeneous and changing landscapes. The model provides a broader-scale context for our field studies and will permit evaluation of impacts on species of alternative land-use and fragmentation patterns overlaid on natural environmental heterogeneity. This work complements the efforts on understanding the effects on environmental heterogeneity on communities and on understanding and predicting human land-use dynamics in the region. Investigators and Collaborators:
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