Secondary production of Rhyacophila minora, Ameletus sp., and Isonychia bicolor from streams of low and circumneutral pH in the Appalachian Mountains of West Virginia

Abstract

We estimated the secondary production of Rhyacophila minora, Ameletus sp., and Isonychia bicolor in three acidic streams and one circumneutral stream in Randolph County, West Virginia. Quantitative benthic samples were collected monthly from these second-order streams from November 1990 to October 1991. Mean pH values in the acidic streams were 4.5, 4.8, and 4.8, and mean pH in the circumneutral stream was 6.7. Production estimates for Rhyacophia minora in the acidic streams were 49.6, 19.2, and 15.8 mg m−2 y−1. Production of R. minora in the circumneutral stream was 1.0 mg m−2 y−1. Ameletus sp. production estimates for the acidic streams were 144.8, 176.8, and 208.3 mg m−2 y−1. Ameletus sp. production in the circumneutral stream was 7.4 mg m−2 y−1. Secondary production of I. bicolor in the circumneutral stream was 116.6 mg m−2 y−1. No Isonychia were collected from the acidic streams. The higher production of R. minora and Ameletus sp. in the acidic streams may be associated with differences in macroinvertebrate community structure.