This U.S. EPA STAR-supported research project was the product of an interdisciplinary team of Ohio University researchers and members of the Appalachian Watershed Research Group. Although much early environmental research traditionally occurred within narrow scientific disciplines, today’s environmental challenges and solutions cross disciplinary boundaries and necessitate expertise in biology and ecology, hydrology, geology and geomorphology, chemistry, geography and engineering.

This project refined the classification of fish and macroinvertebrate assemblages in least impacted reference sites of the Western Allegheny Plateau (WAP) ecoregion of Ohio and developed tools for identification of environmental stressors in watersheds of this region. Classification of waters is fundamental to develop of accurate biological endpoints for Clean Water Act (CWA) aquatic life uses. Our research affirmed that the existing classification based on stream size was appropriate and that refinements to include level IV ecoregions (subregions) were not required. Analysis of non-geographically dependent abiotic variables in reference sites identified stream gradient as a variable that should be incorporated into Ohio’s biocriteria in the WAP ecoregion.

Ohio’s reference sites are “least impacted,” not pristine, and our analyses identified an anthropogenic signature in the data related to land use and dissolved materials. This pattern is expected given that these are human occupied landscapes. In managing Ohio’s waters this was accounted for in development of Ohio’s tiered aquatic life uses (ALUs) designed to protect baseline CWA goals (e.g., Ohio’s Warmwater Habitat ALU) and those performing better (Ohio’s Exceptional Warmwater Habitat ALU). Related research summarizing trends in Ohio’s reference sites statewide over the past 15 years has documented improvements in biological reference site condition from point source pollution reductions (larger streams) and what is likely the implementation of agricultural best management practices to reduce soil erosion in small waters.

Our effort to develop regional, watershed, and stream-based tools to identify stressors responsible for aquatic life impairment resulted in the development of a series of univariate ceiling or floor response curves that can be used in local stressor identification efforts. In addition we tested a process for using multiple multivariate data exploration tools at sites in the WAP ecoregion that can be used to select stressor variables likely limiting to aquatic life in regions of the WAP and used to develop watershed and regional TMDLs, Acid Mine Abatement (AMDAT), and watershed restoration plans. Both the uni-variate stressor associations and the regional multivariate tools reduce limitations from local assessments that lack a sufficient stressor gradient to identify meaningful limiting stressors.

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