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A pH/UV-B synergism in amphibians.

abstract1 (full description below): Conservation Biology: 1301-1303.
pH/UV-B synergism. PDF/Acrobat file     Long, Saylor, and Soule

Introduction Some workers have proposed that synergistic interactions may contribute to the decline and disappearance of amphibians (Blaustein & Wake 1990; Carey 1993; Blaustein et al. 1994a). In this pilot study, we tested the effects of low pH and increased ultraviolet-B radiation (UV-B) on frog-embryo survival. Blaustein et al. (1994b) correlated differences in declines in three anuran species in the Cascades with differences in their abilities to repair UV-B-induced DNA damage and in embryo survival in UV-B-screened enclosures in the field. Low pH has been shown by numerous researchers to decrease the survival of amphibian embryos (Freda 1986). In a review, however, Dunson et al. (1992) found no evidence that low pH was a factor in declines of Rana muscosa and Bufo canorus in the Sierra Nevada, and they reported similar results for Rana pipicns and Bufo boreas in the Rocky Mountains. Several ranid frogs have apparently suffered recent population declines (Bradford 1991; Fellers & Drost 1993; Blaustein 1994&). We studied the possibility of a pH/UV-B synergistic effect on the mortality of Ranapipiens embryos.