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Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Unionid Ecology
Modeling mussel diversity from bankfull geometry and environmental factors in the Neversink River, New York, USA
B.P. Baldigo1, C.D. Apse2, G.E. Schuler2, and B.E. Westergard3. 1U.S. Geological Survey, 425 Jordan Road, Troy, NY 12180, 2The Nature Conservancy, Neversink River Program, 108 Main Street, New Paltz, NY 12561, 3National Weather Service, 1329 Airport Road, Jackson, KY 41339
Declines in the distribution, abundance, and diversity of freshwater-mussel communities have been reported worldwide. Identifying causes for observed alterations are problematic because previous studies have isolated only a few factors that directly affect mussel-species populations. Mussel communities, habitat, water chemistry, and bankfull hydrology and geomorphology were characterized at 40 reaches in the Neversink River of southeastern New York during 1997-2002 to evaluate factors that affect species diversity (richness). An empirical model of community richness was developed from relations with (1) chemistry (sulfate, calcium, phosphorus, and acid-neutralizing capacity), (2) drainage area and elevation, (3) bottom materials (percent sand and 84th-percentile particle size), (4) channel width, slope, and water velocity, and (5) shear stress at bankfull discharge. Combinations of these variables accounted for as much as 62% of the variability in mussel-species richness. The model correctly characterized richness at all sites to within 1 species and can predict the distribution of certain species because assemblages generally consist of fixed grouping (0-1 species upstream and 4-6 species downstream). This model can help evaluate effects that changes in hydrologic, chemical, or geomorphic conditions might have on mussel assemblages throughout this basin and increase the understanding of mussel communities in rivers of the region.
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