Herpetofaunal and vegetational characterization of a thermally-impacted stream at the beginning of restoration

Pen Branch, a third order stream on the Savannah River Site (SRS), located near Aiken, SC, USA, received thermal effluents from the cooling system of a nuclear production reactor from 1954 to 1988. The thermal effluent and in creased flow destroyed vegetation in the stream corridor (i.e, impacted por tion of the floodplain), and subsequent erosion created a braided stream sy stem with a greatly expanded delta. Restoration of the area began with plan ting of bottomland hardwood species in 1993. Occurrence of amphibians and r eptiles was monitored by daily sampling from 1 January 1995 through 30 Sept ember 1996 to characterize the course of the restoration. Vegetation was sa mpled in the summer of 1996 to characterize the habitats in the unimpacted riparian zone and the impacted stream corridor. A total of 12 580 individua ls representing 72 species of herpetofauna were captured. There were no sig nificant differences in relative abundance or diversity of herpetofauna in unplanted versus planted zones within the impacted corridor 3 years after p lanting. Likewise, there were no significant differences in abundance or di versity of herpetofauna in the upper and lower corridor areas, which differ ed in site preparation before planting, or in riparian zones of different w idths. However, species diversity of amphibians and reptiles in the unimpac ted riparian zone was significantly higher than on vegetated islands locate d between stream braids within the impacted floodplain corridor. There were also significantly more species and individuals within the riparian zone t han in the corridor, and the species assemblage within the riparian zone di ffered from that of the corridor. Woody vegetation within the unimpacted ri parian zone was significantly higher in basal area than on islands within t he corridor. (C) 2000 Elsevier Science B.V. All rights reserved.