The influence of adjacent land uses on macroinvertebrate communities of prairie streams in Missouri

The impact of adjacent land uses on aquatic macroinvertebrate communities was assessed in three low gradient, prairie streams in Missouri, USA. Aquatic macroinvertebrates were collected from 17 sites during fall 1999, and spring and summer 2000; each site was bordered by a single land use practice. We found no significant differences in taxa, diversity [richness, abundance, or Fisher's log-series alpha (FLSA)] or composition metrics (richness and abundance of EPT taxa, functional feeding groups or Chironomidae) attributable to adjacent land use during any season. However, FLSA was significantly affected by the distance of a site from the beginning of the perennial stream during the spring and summer. Little of the variation in taxa diversity was attributable to physicochemical factors. However, these factors were more important in explaining differences in diversity among sites during the drought (fall 1999) than in other seasons. Taxonomic composition of the macroinvertebrate community effectively discriminated among sites bordered by different land uses. Although compositional differences were season-specific, predators and chironomids were the most important groups accounting for significant differences among land use groups regardless of season. Moreover, compositional analysis, based on proportional abundances of taxa, revealed the importance of both stream identity and adjacent land use to community structure.