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ULTRAVIOLET RADIATION DOSE AND AMPHIBIAN DISTRIBUTIONS IN NATIONAL PARKS
Citation:
Diamond, S A., N E. Detenbeck, D F. Bradford, P. C. Trenham, M. J. Adams, P. S. Corn, B. Hossack, AND R. A. Knapp. ULTRAVIOLET RADIATION DOSE AND AMPHIBIAN DISTRIBUTIONS IN NATIONAL PARKS. Presented at 2002 SETAC Annual Meeting, Salt Lake City, UT, November 14-20, 2002.
Description:
Ultraviolet Radiation Dose and Amphibian Distributions in National Parks. Diamond, S. A., Detenbeck, N. E., USEPA, Duluth, MN, USA, Bradford, D. F., USEPA, Las Vegas, NV, USA, Trenham, P. C., University of California, Davis, CA., USA, Adams, M. J., Corn, P. S., Hossack, B., USGS, Knapp, R. A., University of California, Mammoth Lakes, CA., USA. Ultraviolet B radiation (UV-B) has increased globally over the last several decades due to reduction of stratospheric ozone. Although ozone loss has been largely controlled, UV-B may also increase as climate change alters cloud cover, rainfall, and distributions of vegetation. In aquatic systems, these factors also alter dissolved organic carbon, a strong absorber of UV-B. Because UV-B can be extremely toxic, even small increases are of great concern. This concern, and the suggestion that amphibians are in worldwide decline, has fostered the hypothesis that UV-B radiation affect amphibian populations. We addressed this hypothesis by using landscape-level surveys in which the relationship between amphibian distributions and estimated UV-B doses were examined. We used field surveys to quantify the UV-filtering capacity of wetland water and the effect of landscape, as well as models that incorporate the effect of ozone, clouds, landscape, location, specific date, and exposure duration. UV-B dose estimates and amphibian distribution surveys (as well as numerous habitat variables) were completed for 1026 wetlands. Analyses of the relationship of estimated UV dose and the presence of amphibian species indicated that UV dose was a good predictor of amphibian distribution for three of eight species/park combinations. However, for one species, Ambystoma macrodactylum, the relationship was positive in one park, and negative in another. In nearly all cases, pond type and elevation were the most consistent determinant of species presence. Generally, it appears that the species examined (except perhaps Rana cascadae) are largely unaffected by UV-B.