Elkhart Area Rivers Macroinvertebrate Assemblage Summary 2012

The Midwest Biodiversity Institute, Inc. (MBI) has conducted macroinvertebrate sampling of streams and rivers in the Elkhart, Indiana area on behalf of the City of Elkhart, Public Works and Utilities Department since 2004. Samples were collected from 14 sites in 2012 with 13 repeat locations and 1 new site. Sampling was conducted using modified Hester-Dendy artificial substrate samplers and a qualitative dip net/hand pick method in accordance with Ohio EPA macroinvertebrate assessment procedures. These methods and the attendant biocriteria have been used since 2004 primarily because Indiana then lacked a comparable assessment framework for macroinvertebrates. Of the 14 sites sampled in 2012, 4 sites met the EWH biocriterion (ICI ≥46; exceptional), 8 sites fully met the WWH biocriterion (ICI ≥ 36; good), one site was in non-significant departure of WWH, and one site did not meet the WWH biocriterion. In terms of comparisons to prior year results, four sites exhibited significant increases (>4 ICI units) in the ICI score while five sites exhibited a significant decline (Table 1). The remaining 5 sites exhibited changes that were within the 4 ICI unit departure threshold and were considered to be virtually unchanged.

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