Intra- and Inter-Watershed Variability in Benthic Macroinvertebrate Community Diversity, Taxa Richness, and Biotic Integrity: Citizen Scientist Sampling Within a Minnesota USA Region Dominated by Agriculture

ABSTRACT: Volunteer citizen scientists collected benthic macroinvertebrate samples from 35 streams throughout multiple watersheds in southeastern Minnesota, USA, during the period 1999–2013 to assess community diversity, taxa richness, and biotic integrity as indicators of water quality and general habitat conditions. In total, 452 invertebrate samples containing >46,000 organisms were collected, processed, and analyzed. Only 45% of the citizen scientists completed their 5-year sampling commitment. However, their samples generally demonstrated significant differences in total taxa richness, Ephemeroptera-Plecoptera-Trichoptera (EPT) taxa richness, Simpson and Shannon diversities, and a regional benthic index of biotic integrity (BIBI) within and/or among the watersheds examined. Streams in the two larger watersheds averaged significantly higher taxa richness and BIBI scores than those in smaller watersheds. Overall, streams in this region exhibited mostly poor or very poor biotic integrity based on their macroinvertebrate communities, indicating continued impacts from environmental stressors within these agricultural watersheds.