GROWTH AND SECONDARY PRODUCTION OF PARACAPNIA-ANGULATA HANSON (PLECOPTERA, CAPNIIDAE) IN APPALACHIAN STREAMS AFFECTED BY ACID PRECIPITATION

Paracapnia angulata in West Virginia occurs in headwater streams that range in pH from 4.5 to 7.5. It is representative of a number of speci es of Plecoptera, which often increase in abundance in acidic streams because they are tolerant of low pH and related changes in water quali ty associated with acid precipitation. We compared growth rates and se condary production of P. angulata in four streams, SFR, WS4, WS3, and HSR, in which mean streamwater pH was 4.26, 5.99, 6.07, and 7.48, resp ectively. Mean specific growth rates, in terms of dry mass for P. angu lata, were higher in the two neutral streams than in the more alkaline stream or the acidic stream. Secondary production of P. angulata was highest in the acidic stream SFR, 106.2 +/- 16.4 mg . m-2 . yr-1 (mean +/- 2 SE), and was 34.0 +/- 12.1 mg . m-2 . yr-1 in WS4, 32.7 +/- 3.8 mg . m-2. yr-1 in WS3, and 35.4 +/- 3.6 mg . m-2 . yr-1 in HSR. The i ncreased secondary production of P. angulata was related to greater me an abundance and biomass in SFR; and the production/biomass ratio for this acidic stream was lower than for the other streams.