Multiple mesohabitats and genera of Chironomidae in monitoring assessment protocols of two Ozark streams

Stream assessment is a critical factor in monitoring water quality nationally.  Criteria and measures may change with region according to natural variation and community dynamics.  In Missouri, the Stream Condition Index (SCI) was developed to efficaciously measure stream macroinvertebrate responses to organic pollution, agriculture, acidity, logging, heavy metals, insecticides, and habitat degradation.  Typically, stream assessment is conducted in riffles only and analyzed with Chironomidae left at the family level.  Our objectives were to quantify the effects of considering multiple mesohabitats and genera of Chironomidae on macroinvertebrate stream condition assessment.  We used the SCI (incorporates taxa richness, Ephemeroptera, Trichoptera, and Plecoptera richness, biotic index, and Shannon’s Diversity Index) to measure stream condition.  Five surface-fed and spring-fed tributary replicates of the Jacks Fork and Current rivers were sampled for benthic macroinvertebrates using a Brown vacuum sampler.  Taxa were identified to the genus level and Chironomidae larvae were analyzed at the generic level of taxonomic resolution.  Both individual metrics and the composite SCI score were used to determine stream condition in riffle mesohabitats.  Additional mesohabitats included pools and marginal vegetation for comparison to riffles using one-way ANOVAs to test differences in SCI and metric values.  Further, these same comparisons were made with the addition of Chironomidae genus-level data.  Results suggest both mesohabitats and Chironomidae at the generic level of recognition should be considered in regional stream assessments.