Evaluating the "Representative Reach" Component of Rapid Bioassessment Protocol: Variation among Candidate Stream Reaches. (Environmental Science & Ecology).

Evaluating the "Representative Reach" Component of Rapid Bioassessment Protocol: Variation among Candidate Stream Reaches. Mike Buth * and James P. Dunn, Grand Valley State University, Biology Department, Allendale, MI 49401; 616/844-5433

Rapid Bioassessment Protocol (RBP) is a set of guidelines developed by the U. S. Environmental Protection Agency to standardize the practice of using qualitative survey techniques on aquatic organisms to gauge stream health. One component of RBP involves selecting a small section of a stream, known as a "representative reach," which is supposed to represent the conditions found over a larger area of the stream. This study was conducted to examine the variability between reaches in close proximity to each other, and to determine if that variability could be great enough to influence RBP results. Pour candidate "representative teaches" were sampled in each of three separate Michigan streams with varying anthropogenic disturbance. Differences among reaches were then evaluated using three common indices: the number of Ephemeropteta, Plecoptera, Trichoptera (#EPT); the Sequential Comparison Index (SCI); and the Michigan Department of Environmental Quality "Procedure-51" biotic index. Results indicate little variab ility between reaches in streams with little impact and much greater variability between reaches in streams impacted by development. This suggests that monitoring programs for impacted streams may need to sample more reaches to describe conditions compared to streams with little impact.

* Indicates the person who presented the paper