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Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Survey Design 2
Design and indicator considerations for a probabilistic survey of U.S.A. great rivers: Missouri, Mississippi, Ohio
B.H. Hill1, D.W. Bolgrien1, T.R. Angradi2, and E.W. Schweiger2. 1U.S. Environmental Protection Agency, Mid-Continent Ecology Division, Duluth, MN, USA 55804, 2U.S. Environmental Protection Agency, Mid-Continent Ecology Division, Denver, CO, USA 80202
Great River ecosystems (GRE) include the river channel and associated backwaters and floodplain habitats. The challenge in designing a GRE monitoring and assessment program is to choose a set of habitats, indicators and sampling locations that reveal the ecological condition of the GRE at an appropriate scale, without bias, and at an affordable price. A comprehensive and reliable assessment requires sampling a variety of biotic assemblages, including organisms of contrasting size and mobility, in a variety of GRE habitats. These assemblages may be rich in taxa or they may be important for ecosystem structure and function. Measurements of the toxicity of waters and sediment and contaminant levels in fish tissues are needed to assess the extent of toxic contamination within the river system. The influence of physical structure across spatial scales ranging from substrate particles to channel and floodplain morphology is needed to interpret biological responses to anthropogenic stressors. Large-scale habitat structure influences the processes of groundwater flow, inundation, water velocity, and the mobilization, transport, and deposition of sediments, organic matter, and dissolved substances. These, in turn, determine micro- and meso-scale habitat structure, which act as a template for aquatic biota that varies in their habitat requirements.
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