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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Bioassessment
RELATIONSHIPS BETWEEN RIPARIAN VEGETATION, WATER CHEMISTRY, AND STREAM INVERTEBRATES IN A SOUTHERN ILLINOIS AGRICULTURAL LANDSCAPE.
M.L. Stone1, M.R. Whiles1, J.A. Webber2, and K.J. Williard2. 1Department of Zoology, University of Southern Illinois, Carbondale, IL 62901, 2Department of Forestry, University of Southern Illinois, Carbondale, IL 62901
Invertebrate bioassessment, habitat analysis, GIS analyses of watershed land use and riparian land cover, and water chemistry data were used to examine relationships in an agricultural region of Southern Illinois. Invertebrate rapid bioassessment and in-stream physical habitat analyses of 15 headwater streams were conducted in April 2001. Water chemistry samples were collected monthly at each of these sites for 1 year. Three of the 15 streams were also intensively monitored by collecting quantitative benthic cores and by establishing automated water sampling stations. Invertebrate data indicated biological integrity was most closely linked to in-stream habitat, riparian land cover, and water chemistry. Hilsenhoff index scores were negatively correlated with in-stream physical habitat scores (r2 = 0.64, P = 0.0003) and percent forested land cover in 15-m riparian zones (r2 = 0.54, P = 0.0018), and positively correlated with orthophosphate (r2 = 0.65, P = 0.0003) and ammonium (r2 = 0.43, P = 0.0075) concentrations. Quantitative invertebrate data from the three intensively monitored streams supported these same trends. Results show that macroinvertebrate assemblages in these highly degraded streams can reflect differences in land use and physicochemical habitats. Results also indicate that riparian land use is an important component of biological integrity in agricultural streams.
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