MACROINVERTEBRATE COMMUNITIES IN HEADWATER STREAMS AFFECTED BY ACIDICPRECIPITATION IN THE CENTRAL APPALACHIANS

We collected quantitative macroinvertebrate samples monthly from Septe mber 1989 to October 1990 from four streams on the Allegheny Plateau o f West Virginia that were characterized by different bedrock geology a nd streamwater pH. Mean pH was 4.3, 6.1, 6.0, and 7.5 in the four stre ams. We compared species and functional group composition of the benth ic macroinvertebrate community in these streams to choose taxa that co uld be used as indicator species for differences in pH in bioassessmen t studies. The streams differed in species composition and abundance a nd several species were found that could be used as indicators for eac h of the levels of pH. Higher densities of Amphinemura sp., Leuctra sp ., Euryophella funeralis, and Paracapnia angulata were characteristic of the stream with a pH of 4.3. Higher densities of Peltoperla arcuata and Wormaldia moesta were found in the streams with a pH of about 6.0 . Gammarus minus, Baetis sp., Ephemerella dorothea, and Sweltsa sp. we re found at higher densities in the stream with a pH of 7.5.