SAVING THE mountain yellow-legged frog

The mountain yellow-legged frog was once the most abundant amphibian in the Sierra Nevada Mountains and Transverse Ranges of Southern California. Only a few decades ago, it was difficult to walk around many of California’s alpine lakes without tripping over these diminutive “mountain gnomes.” Today the hardy survivors of freezing, high-elevation winters are vulnerable to a host of modern threats, which have driven the frogs extinct in more than 93 percent of their old mountain homes.

The mountain yellow-legged frog has two different populations that may actually be separate species: a northern and central Sierra Nevada population and a southern Sierra Nevada and Southern California population. Both populations are adapted to high-elevation habitats without aquatic predators. So it’s not surprising that the main reason for the frog’s decline is the California Department of Fish and Game’s introduction of nonnative trout to high alpine lakes. These stocked fish prey upon tadpoles and juvenile frogs, and scientists predict that the yellow-legged frog could be extinct within decades.

Although the frog has disappeared from the vast majority of known historical locations — and most of the largest remaining populations have recently collapsed — the U.S. Fish and Wildlife Service continues to refuse to protect the Sierra Nevada population under the Endangered Species Act. The Center filed a petition to add the Sierra Nevada population to the endangered species list in 2000, but the Service instead placed these frogs on the candidate list, a regulatory purgatory that offers no substantive protections.

The Center is working to gain full federal Endangered Species Act protection for Sierra Nevada mountain yellow-legged frogs — and meanwhile, thanks to our work, the California Fish and Game Commission designated all populations of the mountain yellow-legged frog as a candidate species, the first step toward a state listing as endangered or threatened.

Southern California mountain yellow-legged frogs have been protected under the Endangered Species Act for about a decade, but the Service has yet to develop a recovery plan to guide their management. To speed recovery of the frogs and other imperiled California amphibians without recovery plans, the Center launched a lawsuit to force the Service to develop the legally required plans.