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DEVELOPMENT OF AN INDEX OF BENTHOS INTEGRITY USING MACROINVERTEBRATES FOR NEW JERSEY LAKES AND RESERVOIRS
Citation:
Blocksom, K A., J. P. Kurtenbach, D J. Klemm, F A. Fulk, AND S M. Cormier. DEVELOPMENT OF AN INDEX OF BENTHOS INTEGRITY USING MACROINVERTEBRATES FOR NEW JERSEY LAKES AND RESERVOIRS. Presented at North American Benthological Society, Keystone, CO, May 29-June 2, 2000.
Impact/Purpose:
The goal of this research is to develop methods and indicators that are useful for evaluating the condition of aquatic communities, for assessing the restoration of aquatic communities in response to mitigation and best management practices, and for determining the exposure of aquatic communities to different classes of stressors (i.e., pesticides, sedimentation, habitat alteration).
Description:
Recently there has been a greater focus by the USEPA on bioassessment and biocriteria development for lakes and reservoirs. In this study a multimetric index was developed to evaluate the condition of New Jersey lakes and reservoirs using benthic macroinvertebrates. Samples were collected from 58 New Jersey lakes during summer 1997. Thirty-three candidate metrics were evaluated using a step-wise process to evaluate discriminatory power, relative scope of impairment, redundancy, and stressor relationships with metrics, eliminating those failing to meet specific criteria. Five metrics were selected for the Lakes Macroinvertebrate Integrity Index (LMII): Hilsenhoff Biotic Index, percent chronomid individuals, percent collector-gatherer taxa, percent oligochaetes and leeches, and number of Diptera taxa. Scores were based on the cumulative distribution function of each metric, and metric scores represent the fraction of the best attainable value (95th or 5th percentile) achieved at a site. The five metric scores were summed into the LMII. The LMII discriminates well between reference and impaired lakes and is strongly related to several stressors. Biocriteria were created based on the distribution of LMII scores among reference lakes. The results suggest that lakes in more heavily populated areas are more likely to be in poor condition.