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A TEST OF WATERSHED CLASSIFICATION SYSTEMS FOR ECOLOGICAL RISK ASSESSMENT
Citation:
Detenbeck, N E., S L. Batterman, V. J. Brady, J. C. Brazner, V M. Snarski, D L. Taylor, J A. Thompson, AND J. W. Arthur. A TEST OF WATERSHED CLASSIFICATION SYSTEMS FOR ECOLOGICAL RISK ASSESSMENT. Environmental Toxicology & Chemistry. SETAC Press, Pensacola, FL, 19:1174-1181, (2000).
Description:
To facilitate extrapolation among watersheds, ecological risk assessments should be based on a model of underlying factors influencing watershed response, particularly vulnerability. We propose a conceptual model of landscape vulnerability to serve as a basis for watershed classification systems to predict resistance and resilience of aquatic ecosystems to hydrology-related stressors. Watershed area, storage capacity, channel slope, and soil permeability determine sensitivity of lotic systems to stressors associated with land-use activities that impact hydrologic regimes. natural hydrologic disturbance regimes also influence the resilience of aquatic systems by selecting for life history strategies. Natural hydrologic disturbance regimes also influence the variability in some of these physiographic driving factors can be partitioned by landscape classification schemes such as the U.S. Forest Service Ecological Unit Classification System, while others mat explain remaining variability within watershed storage and land-clearing activities in watersheds surrounding the western arm of Lake Superior. Initial results for second-order watersheds indicate significant watershed class effects on baseflow water quality, percent motile biraphid diatom species in periphyton communities, habitat quality, and fish community integrity. Future studies have been delayed to examine cumulative effects downstream.