The mountain yellow-legged frog was once the most abundant amphibian in the Sierra Nevada 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 t han 93 percent of their old mountain homes.

The mountain yellow-legged frog has two different populations that have been declared separate subspecies: 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 alpine lakes. These stocked fish prey upon tadpoles and juvenile frogs, and scientists predict that the yellow-legged frog could be extinct within decades. It has disappeared from the vast majority of known historical locations, and most of the largest remaining populations have recently fallen to near-collapse.

Gray wolfTrump threatens our nation's democracy, health and environment — including elephants.
Please take our pledge to resist Trump and stand up for wildlife.


The Center first filed a petition to add the Sierra Nevada population to the endangered species list in 2000. Finally in 2013, as a result of a historic 2011 settlement agreement with the Center that is also speeding protection decisions for 756 other species, the Service proposed federal Endangered Species Act protection for Sierra Nevada yellow-legged frogs, along with more than 2 million acres of proposed critical habitat — but after it had dragged its feet for years on taking next steps, in March 2016 we sued. In August we won a  settlement requiring the Service to determine whether the foothill yellow-legged frog warrants protection by 2020. Meanwhile that year, the U.S. Forest Service had been warned we'd sue that agency for authorizing livestock grazing on the Humboldt-Toiyabe National Forest without considering the potential impacts to federally protected Sierra Nevada yellow-legged frogs, as well as Yosemite toads.

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. In 2014 we reached a settlement agreement requiring the Service to develop a recovery plan for Southern California's mountain yellow-legged frogs by December 2018.

And thanks to our work, the California Fish and Game Commission has designated all populations of the mountain yellow-legged frog as "candidates" for listing, the first step toward a state listing as endangered or threatened.