Evaluation of Herpetofaunal Communities on Upland Streams and Beaver-Impounded Streams in the Upper Piedmont of South Carolina

Abstract

Beavers (Castor canadensis) create numerous scattered wetlands in the southeastern United States that alter the composition of aquatic and adjacent terrestrial communities. However, the influence of beaver ponds on communities of amphibians and reptiles (herpetofauna) is poorly known. We used drift fences, coverboards and aquatic traps to compare herpetofaunal communities from unimpounded streams (n = 3) with those of beaver ponds (n = 3) in the Piedmont of South Carolina during 1998 and 1999. We also characterized differences in environmental and upland habitat attributes between beaver ponds and unimpounded streams. There were no significant differences in overall herpetofaunal abundance between unimpounded streams and beaver ponds, although significantly more salamanders were captured at unimpounded streams and significantly more anurans, lizards and turtles were captured at beaver ponds. Estimates of amphibian and reptile species overlap were high for beaver ponds and unimpounded streams. However, the richness (S), diversity (H′) and evenness (J′) of amphibians were significantly higher at unimpounded streams than at beaver ponds. In contrast, the abundance, richness and diversity of reptiles were significantly higher at beaver impoundments. Differences in amphibian and reptile community attributes between beaver ponds were related to the lotic or lentic habitat requirements of individual species and the effects of beaver impoundments on surrounding terrestrial habitats. Our study indicates that natural disturbances resulting from beaver-created wetlands increase regional abundance and diversity of herpetofauna.