摘要：I examined the sensitivity of 16 biological metric scores derived from benthic macroinvertebrate assemblages of small streams in New River Gorge National River. A stream presumed to have its macroinvertebrate assemblage structure impaired by an abandoned landfill (Rush Run) was used to represent the “impacted” condition. It's fauna were collected from two longitudinally distinct loci and compared to two sets of reference streams because upper and lower elevation streams exhibited marked difference in benthic community structure. Thus, a site on upper Rush Run was contrasted to five other “upper” reference streams and a site on lower Rush Run was compared to five “lower” reference streams with a one sample t-test. Most of the selected metrics highlighted the impairment of lower rush run, relative to lower streams. Whereas only Ephemeroptera-Plecoptera-Trichoptera richness and three variants of the biotic index described impairment of upper Rush Run. Subsequent power analysis indicated that both upper and lower reference streams had similar statistical sensitivity, but that environmental sensitivity was greatly reduced at upper elevations streams. This was probably due to harsher environment of upper streams (intermittent flow, reduced buffering capacity).
