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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Disturbance Ecology IV
ASSESSING THE IMPACTS OF ENVIRONMENTAL STRESSORS ON MACROINVERTEBRATE INDICATORS IN OHIO.
S. Majumder1, F.A. Fulk2, and S.M. Cormier2. 1SoBran, Inc.; c/o U.S. Environmental Protection Agency, Cincinnati, Ohio, 2Ecosystems Research Branch/Ecological Exposure Research Div./National Exposure Research Lab., U.S. Environmental Protection Agency Cincinnati, Ohio
Macroinvertebrate indicators are used as assessment endpoints for surface water quality monitoring in Ohio. The purpose of this study is to explain and predict the impacts of environmental stressors on macroinvertebrate communities as measured by the Ohio Environmental Protection Agency's Invertebrate Community Index (ICI). First, the impact of each stressor on macroinvertebrate communities was identified. Among water chemistry variables, ammonia, total Kjeldahl nitrogen, phosphorus and pH were found to have the greatest impacts. Physical conditions that had the greatest impacts were riffles, pools and the degree of channelization. Second, statistical models were developed to predict the probability of criterion attainment for the ICI and its metrics as a function of the environmental stressors and the interactions between them. The statistical modeling was done using a variant of the logistic regression procedure. The results indicate that by using data for the entire state, scores for the ICI and its metrics can be predicted correctly at 60-65% of the sites. These results can potentially be used for identification of sites with high risks of macroinvertebrate community degradation, and for "threshold" development of stressors. The statistical models are currently being crossvalidated for further use and detailed focus on smaller areas.
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