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 species of Plecoptera, which often increase in abundance in acidic streams because they are tolerant of low pH and related changes in water quality associated with acid precipitation. We compared growth rates and secondary 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, respectively. Mean specific growth rates, in terms of dry mass for P. angulata, 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 increased secondary production of P. angulata was related to greater mean abundance and biomass in SFR; and the production/biomass ratio for this acidic stream was lower than for the other streams.