Aquatic invertebrate monitoring at Ozark National Scenic Riverways, 2005-2014

Bowles, David; Cribbs, J.; Hinsey, Janice

In 2005, the National Park Service Heartland Inventory and Monitoring Network began intensively monitoring the condition of streams at Ozark National Scenic Riverways (OZAR) by assessing aquatic invertebrate community structure following a monitoring protocol developed specifically for the park. Two broad objectives are addressed by this protocol: 1) determine the status and trends of invertebrate species diversity, abundance, and community metrics, and 2) relate the invertebrate community to overall stream condition through quantification of metrics (species richness, abundance, and diversity) and to region-specific multi-metric indices as indicators of water quality and habitat condition. This report summarizes the results of monitoring from 2005 through 2014. Nine mainstem river sites (6 Current River, 3 Jacks Fork) and 6 tributary sites (sampled on a rotational basis) were sampled during a November-February index period. At each sampling site, three benthic invertebrate samples were collected from each of three successive riffles using a Slack-Surber sampler. Taxa were identified to the lowest practical taxonomic level (usually genus) and counted. Aquatic invertebrate metrics calculated for the samples included taxa richness; Ephemeroptera, Plecoptera, Trichoptera (EPT) richness; Shannon Diversity Index; and Hilsenhoff Biotic Index. The invertebrate metrics calculated for sampling sites were generally consistent with those previously reported for unimpaired streams in the Ozark region. Missouri Stream Condition Index (SCI) scores for all mainstem river sites across years indicated they were largely fully biologically supporting (SCI ≥16). These streams have the capability of supporting and maintaining a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of the natural habitat of the region. Tributaries also generally had SCI scores that indicated they were fully biologically supporting. Anthropogenic activities along the Current River and Jacks Fork and the majority of their respective tributaries generally have not reduced SCI index scores below biologically supporting. Ozark Rivers Stream Invertebrate Multimetric Index (ORSIMI) scores demonstrated a wide range of variation between 2012 and 2014 relative to the baseline. More data will be required to fully evaluate the utility of this metric. The general assessment of this report is that OZAR streams are of high quality. Aquatic invertebrate monitoring at OZAR provides a sound tool for early detection of a decline of water quality at OZAR.

Aquatic invertebrate monitoring at Ozark National Scenic Riverways, 2005-2014

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