An unprecedented loss of the variety and numbers of plant and animals species around the world is occurring. Habitat destruction, over-harvesting, chemical pollution, introduced exotic species, and climatic change are among the major threats to living species. In particular, many species of amphibians are undergoing drastic population declines and range reductions. The amphibian declines are especially perplexing because many species are disappearing in pristine habitats. Atmospheric factors, perhaps acting with other agents, may be contributing to the declines. Using amphibians, Dr. Blaustein and his colleagues propose to investigate one potential atmospheric source of biological trauma, ultraviolet radiation (UV), that may have significant biological effects ultimately contributing to population declines. Amphibians are excellent "bioindicators" of environmental change, due in part to their relatively thin, permeable and unprotected skin. The decline in amphibians may be an early warning signal and ultimately, other organisms, including humans, may be in peril. Results should yield information with broad implications regarding the potential for atmospheric effects on other organisms. The investigation will be focused at several levels of biological organization including molecular, individual, and population levels. Laboratory and field experiments will examine the effects of natural levels of UV on developing tadpoles and on the reproductive physiology of adult frogs. How UV-damaged DNA is repaired will also be examined. An ecological survey of declining species will be conducted to document their overall population status. This is one of the first studies to incorporate field experiments to investigate the effects of UV on development in wild vertebrates. Since conditions likely to promote increased UV are becoming manifest, it is important to examine whether natural levels of UV have begun to affect the more sensitive animals, like amphibians, so that steps can be taken to reduce a potentially serious environmental threat.
