Relationships between Acidity and Benthic Invertebrates of Low-Order Woodland Streams in the Adirondack Mountains, New York

Benthic invertebrates were collected during January, April, July, and October 1985 from three low-order woodland streams in the Adirondack Mountains, New York to evaluate relationships between acidity and stream invertebrates. Total invertebrate generic richness, generic diversity, Ephemeroptera density and richness, collector–gatherer richness, and scraper density and richness were positively correlated to stream pH. Ephemeroptera and Naididae (Oligochaeta) were absent from the acidic sampling site. Enchytraeid oligochaetes and Turbellaria were collected at all sites, but in significantly higher densities at the acidic site. Elmid beetles (Optioservus ovalis, Oulimnius latiusculus, Promoresia tardella), mayflies (Cinygmula and Baetis) and caddisflies (Glossosoma, Apatania, and Micrasema) were abundant at the sites where pH was highest and were absent from other sampling locales. Total invertebrate density was not decreased at the acidic site when compared with most other sampling sites. Multiple regression analyses revealed that pH and benthic organic matter were the two most important measured stream parameters in describing the variance of invertebrate communities in the three study streams.