Regional Frameworks and Candidate Metrics for Assessing Biotic Integrity in Mid-Atlantic Highland Streams

Abstract
Regionally stratified biological criteria are being used increasingly to assess stream quality. We used multivariate analysis of variance and canonical analysis to examine the utility of two regional frameworks (basins and ecoregions) and 14 candidate metrics of local fish assemblages for assessing the biotic integrity of streams in the mid-Atlantic highlands (montane areas from Pennsylvania to Virginia). In particular, we determined (1) how metrics varied naturally among basins and ecoregions and (2) which metrics varied most consistently with site quality. We also examined the ability of preliminary multimetric indices (MMIs) to distinguish site quality. Metrics varied meaningfully among both basins and ecoregions, but most metrics differed more among basins. The basin effect was especially strong for taxonomic metrics (e.g., number of species [TOTSP]), which reflected the influence of zoogeography on fish community composition. Few metrics differed strongly among both basins and ecoregions. Co...