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THE WESTERN LAKE SUPERIOR COMPARATIVE WATERSHED FRAMEWORK: A FIELD TEST OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED GEOGRAPHICALLY-INDEPENDENT CLASSIFICATION
Citation:
Detenbeck, N E., J. C. Brazner, V. J. Brady, D L. Taylor, AND J A. Thompson. THE WESTERN LAKE SUPERIOR COMPARATIVE WATERSHED FRAMEWORK: A FIELD TEST OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED GEOGRAPHICALLY-INDEPENDENT CLASSIFICATION. Presented at Lake Superior Basin Planning Committee Meeting, Minnesota Pollution Control Association Office, Duluth, MN, October 25, 2000.
Description:
Stratified random selection of watersheds allowed us to compare geographically-independent classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme within the Northern Lakes and Forest (NLF) Ecoregion. In our initial demonstration project, we assessed two hydrologically-based thresholds of impairment, one for watershed storage (5-10%), and one for mature forest coverage (40-60% of watershed in mature forest cover) across two different hydrogeomorphic regions within the Northern Lakes and Forest Ecoregion, the North Shore Highlands Ecological Unit and the Lake Superior Clay Plain Ecological Unit (Maxwell et al. 1995). Main and interactive effects of watershed storage and forest fragmentation on watershed exports, habitat quality, community composition and food-web relationships were compared within and across the two regions. In 1997-1998, 24 second-order stream watersheds were selected to establish a 3-way factorial design. In 1998-1999, third order watersheds in high and low fragmentation classes were selected along gradients of watershed storage within each HGM region to evaluate threshold effects of storage on hydrologic regimes and watershed exports.