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This study tested two key assumptions in developing regional biocriteria: (1) the accuracy of the ecoregion classification framework and (2) the accuracy of standardized qualitative sampling. Except for the Central Appalachians ecoregion, there was little or no correspondence of benthic macroinvertebrate distribution with the ecoregions or subregions of western Virginia. I found that it was more accurate to rearrange the subregions into three larger regions called bioregions: the forested hills and mountains (subregion 69a), valleys and plateaus (subregions 66c, 67a, and 67b), and the mountains (subregions 66a, 66b, 67c, and 67d). As an alternative to the ecoregion classification scheme, I classified my reference sites in biotic groups and then assessed the effect of several environmental variables on discriminating between the groups. There was a 69.8% correct classification rate using 14 environmental variables. Stepwise multiple discriminant analysis and graphical analysis showed that sampling date, slope, pH, habitat assessment score and distance to source were the best predictors of community structure. These environmental variables correctly classified 52.8% of the reference sites. These classification rates are comparable to rates published in similar studies. My study demonstrated that aggregations of subregions into bioregions and a biotic approach are more accurate classification schemes than ecoregions or subregions for biocriteria based on benthic macroinvertebrates. A second study evaluated the accuracy of a standardized qualitative sampling approach, commonly used in rapid bioassessments, in assessing the biological condition of lotic systems. I compared a typical standardized qualitative sampling method with subsampling with a typical quantitative sampling method on a stream with varying degrees of impairment. Although some metrics did respond to differences in sample abundance, overall the two methods made similar estimates of community composition. The two sampling methods made the same assessment an average 89% of the time using multimetric index developed for the Mid-Atlantic Region. I found no pattern showing one method was more accurate in making assessments of biological condition than the other. Given the greater time and costs associated with quantitative sampling methods, I conclude that standardized qualitative methods, are preferable for rapid bioassessment approaches to environmental assessment. / Ph. D.

Research was conducted in three areas of water quality assessment. Long term ecological monitoring data from Shenandoah National Park (SNP) were analyzed and a protocol for data analysis was presented. Streams in SNP were found to be comparable to the best that can be found in the Blue Ridge ecoregion. Land use in SNP (mostly for recreational purposes) does not appear to be causing impairment to the macroinvertebrate assemblages. Streams in the SNP were found to recover quickly from disturbance. The Macroinvertebrate Aggregated Index for Streams (MAIS) was found to have an overall classification efficiency (CE) of 86% in the Ridge and Valley ecoregion, and an overall CE of 91% in the Central Appalachians ecoregion. Refinement of the MAIS for use in the Blue Ridge ecoregion resulted in an increase of the overall CE to 78%. The CE for reference sites in the Blue Ridge was 75%, and the CE for degraded sites was 87%. An intensive study of a stream (Peak Creek) with suspected heavy metal impairment showed that capping of an industrial waste site has resulted in improvements to the macroinvertebrate assemblages. The source of the impairment was not linked solely to heavy metals, but was found to be a mixture of pollution sources and environmental stress. / Ph. D.

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