title: Pesticides are involved with population declines of amphibians in the California Sierra Nevadas.
abstract: Several species of frogs and toads are in serious decline in the Sierra Nevada Mountains of California. These species include the threatened red-legged frog ( Rana aurora ), foothill yellow-legged frog ( R. boylii ), mountain yellow-legged frog ( R. muscosa ), Cascades frog ( Rana cascadae ), western toad ( Bufo boreas ) and Yosemite toad ( B. canorus ). For many of these species current distributions are down to 10% of historical ranges. Several factors including introduced predators, habitat loss, and ultraviolet radiation have been suggested as causes of these declines. Another probable cause is air-borne pesticides from the Central Valley of California. The Central Valley, especially the San Joaquin Valley, is a major agricultural region where millions of pounds of active ingredient pesticides are applied each year (http://www.cdpr.ca.gov/dprdatabase.htm). Prevailing westerly winds from the Pacific Coast transport these pesticides into the into the Sierras.
authors.affiliation: USGS Patuxent Wildlife Research Center, Laurel, MD 20708-4017, USA. Don_Sparling@usgs.gov
authors.forename: D W
authors.initials: DW
authors.lastname: Sparling
authors.forename: G
authors.initials: G
authors.lastname: Fellers
authors.forename: L
authors.initials: L
authors.lastname: McConnell
mesh_terms: D000818:Animals; D002140:California; D010575:Pesticides / Q000506:poisoning*; D011157:Population Dynamics; D011898:Ranidae / Q000254:growth & development*
chemical_list: D010575:Pesticides