Multimetric macroinvertebrate indices for mid-continent US great rivers

Abstract

AbstractWe developed a set of great-river macroinvertebrate indices of condition (GRMINs) for the littoral benthos of mid-continent great rivers in the US (Missouri, Upper Mississippi, and Ohio). We used a multiscale (site, reach, landscape), multimetric abiotic stressor gradient to select macroinvertebrate assemblage metrics sensitive to human disturbance. We used the same stressor gradient to derive reference expectations by empirical modeling. We developed GRMINs for each of 5 reaches: the upper Missouri River, the lower Missouri River, the unimpounded Upper Mississippi River, the impounded Upper Mississippi River, and the Ohio River. We created 2 versions of each index. One version was based on the absolute value (AV) of the correlation between invertebrate metrics and the stressor gradient and potentially included all types of metrics (e.g., diversity, composition, tolerance to pollution, feeding guild). The second version included no tolerance-value-based metrics (NTV). Each index included up to 10 ...