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Presented at the NABS Annual meeting, Anchorage, Alaska, 2006
in Hierarchical Relationships Across Spatial and Temporal Scales
Utilizing Path Analysis to model watershed structure and historical land use affects on local stream geochemistry and ecological responses.
T.S. Schmidt1, W.H. Clements1, S.E. Church2, R.B. Wanty2, D.L. Fey2, L. McEachron3, P.L. Verplank2, J.G. Crock2, M. Adams2, and M.W. Anthony2.1Fishery and Wildlife Department, Colorado State University, Fort Collins, CO, 2U.S. Geological Survey, MS 973 Denver Federal Center, Denver, CO, 3Department of Geography, Flordia State University, Tallahassee, FL
Watersheds are complex systems comprised of terrestrial and aquatic ecosystems which function together to determine local stream geochemistry and aquatic communities. Variance in geochemistry and community composition are influenced by both terrestrial landscape gradients and longitudinal aquatic gradients. Most studies that investigate the linkages between aquatic and terrestrial interfaces do so by means of correlation. However, this approach does not fit the prevailing paradigm to which most aquatic and terrestrial ecologists subscribe: that watersheds are in fact complex hierarchical systems. We are developing geoenvironmental models descriptive of the influence of landscape gradients (i.e. geology, vegetation) on local-scale stream habitat, geochemistry, and community composition. We used Path Analysis and Structural Equation Modeling techniques to develop geoenvironmental models of 200 watersheds from the Central Colorado Mineral Belt. These modeling techniques provide federal land use managers a means to understand the complexity of watershed processes at the landscape-scale and the influence of land use on stream ecology. Results of these studies describe how watershed geomorphology, geology, historical land uses (e.g., mining), and watershed vegetation composition influence sediment transport, water geochemistry and benthic community ecology.
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