"The presence of pesticides and the decrease in cholinesterase activity in Pacific treefrogs suggest that other species, which are more closely associated with water, could be even more affected, said Dr. Gary Fellers, a research biologist and amphibian specialist at the USGS Western Ecological Research Center in California. "Mountain yellow-legged frogs, for example, spend two or three years as tadpoles before they metamorphose and then spend considerable time in the water as adults. Melting of pesticide-contaminated snow could provide a pulse of toxic chemicals at a critical time in the life history of these frogs."

As the nation's largest water, earth and biological science and civilian mapping agency, the USGS works in cooperation with more than 2,000 organizations across the country to provide reliable, impartial, scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, contribute to the sound conservation, economic and physical development of the nation's natural resources, and enhance the quality of life by monitoring water, biological, energy and mineral resources.

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Contact: Catherine Haecker
catherine_haecker@usgs.gov
707-442-1329
United States Geological Survey
6-Dec-2000