Combining data from multiple agencies to assess benthic macroinvertebrate communities in a large gravel-bed river

Abstract

AbstractGovernment agencies frequently conduct benthic macroinvertebrate surveys for bioassessment at large spatial scales in a variety of aquatic habitats, including large rivers. However, these data are rarely used by investigators outside the specific regulatory agency. We used data from 150 benthic macroinvertebrate samples collected over a period of 20 y from 10 locations in a large, shallow river system (the Susquehanna River and 2 major tributaries) by personnel in 4 government agencies to explore broad spatial and temporal patterns in benthic assemblages. We standardized sample size and taxonomy to account for differences in sampling, processing, and identification methods among agencies. Invertebrate assemblages were dominated by mayflies and caddisflies (46–83%). Percent Ephemeroptera, Plecoptera, Trichoptera (EPT) and standard diversity measures were inversely correlated, indicating that traditional macroinvertebrate Index of Biotic Integrity (IBI) approaches might not be applicable to large ri...