Global amphibian declines are of increasing interest and concern, and have puzzled scientists for years because of the inability to identify causal factors. Reports of amphibian declines even in protected areas have led to a recent focus on global stressors such as increasing UV radiation or environmental contaminants as the cause of amphibian declines. The results of a recent study by Roland Knapp (MSI Professional Researcher) and Kathleen Matthews (Research Scientist, Forest Service Pacific Southwest Research Station) in the Sierra Nevada, based on surveys and analyses conducted at an unprecedented geographic scale, clearly links the introduction of non-native fish to the decline of the mountain yellow-legged frog, a once common amphibian species. Their study is unique in that it is one of the first to link amphibian declines to an anthropogenic cause and provides the encouraging finding that with some simple management changes the decline of this species could be reversed. Their findings will soon be published in the journal, Conservation Biology.