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Variation in pesticide tolerance of tadpoles among and within species of ranidae and patterns of amphibian decline

January 1, 2000

There is significant variation among and within amphibian species with respect to reports of population decline; declining species are often found in environments that are physiograpically similar to environments where the same species is thriving. Because variability exists among organisms in their sensitivity to environmental stressors, it is important to determine the degree of this variation when undertaking conservation efforts. We conducted both lethal (time-to-death) and sublethal (activity change) assays to determine the degree of variation in the sensitivity of tadpoles to a pesticide, carbaryl, at three hierarchical levels: among ranid species, among several populations of a single ranid species (Rana sphenocephala), and within populations of R. sphenocephala. We observed significant variation in time to death among the nine ranid species and among the 10 R. sphenocephala populations we tested. Four out of eight R. sphenocephala populations exhibited significantly different times to death among families. The magnitude of the activity change in response to exposure to sublethal carbaryl levels was significantly different among species and within R. sphenocephala populations. Chemical contamination, at lethal or sublethal levels, can alter natural regulatory processes such as juvenile recruitment in amphibian populations and should be considered a contributing cause of declines in amphibian populations.

Publication Year 2000
Title Variation in pesticide tolerance of tadpoles among and within species of ranidae and patterns of amphibian decline
DOI 10.1046/j.1523-1739.2000.99343.x
Authors C. M. Bridges, R. D. Semlitsch
Publication Type Article
Publication Subtype Journal Article
Series Title Conservation Biology
Index ID 70022433
Record Source USGS Publications Warehouse