Bookmark and Share

More press releases

For Immediate Release, June 25, 2007


Jeff Miller, (510) 499-9185
Noah Greenwald, (503) 484-7495
Deanna Spooner, (541) 345-0119

Protection of Highly Endangered Mountain Yellow-legged Frog Delayed Again
Species Protection Waiting List Still Growing:
Not a Single New Species Has Been Protected in More Than a Year

SAN FRANCISCO, Calif.— In response to a lawsuit from the Center for Biological Diversity and Pacific Rivers Council, the U.S. Fish and Wildlife Service today published a “warranted but precluded” decision, agreeing with conservationists that the mountain yellow-legged frog deserves listing as an endangered species, but claiming listing is made impossible by “expeditious progress” on the listing of other species. This is the same decision the agency made more than four years ago, which the Ninth Circuit Court of Appeals determined it had failed to sufficiently support.

"This decision is obviously a political and callous delaying tactic that is a recipe for extinction of the frog," said Jeff Miller, spokesperson for the Center for Biological Diversity. “Given that the Fish and Wildlife Service has not protected a single species in over a year, their claim that protection of the frog is precluded by other listings falls flat.”

The last species protected by the Fish and Wildlife Service were 12 Hawaiian picture-wing flies listed in a single rule on May 9, 2006. Overall, the Bush administration has listed fewer species under the Endangered Species Act than any other administration since the law was enacted in 1973, to date only listing 58 species compared to 512 under the Clinton administration and 234 under the first Bush administration. Since 2001, the number of species designated as “warranted but precluded” and included on the Fish and Wildlife Service’s list of candidate species has grown from 252 to 279 species. At least 25 species have gone extinct on this waiting list after being recognized as candidates for protection.

“The Bush administration has closed the doors on the nation’s endangered species,” said Noah Greenwald, conservation biologist with the Center for Biological Diversity. “If the mountain yellow-legged frog and literally hundreds of other species don’t receive the effective protections of the Endangered Species Act, we will lose them forever.”

Noting the frog survives in as little as 10 percent of its original range in the Sierra Nevada, Deanna Spooner of the Pacific Rivers Council wondered: “How much more endangered does a species have to become before the Fish and Wildlife Service will take action? The intent of the Endangered Species Act is being subverted through administrative delay, sentencing the mountain yellow-legged frog and other species in need of immediate protection to extinction through inaction.”


The mountain yellow-legged frog was historically the most abundant frog in the Sierra Nevada, ranging from southern Plumas County to southern Tulare County at elevations mostly above 6,000 feet. In 1959, Dr. David Wake, a herpetologist with the U.C. Berkeley Museum of Vertebrate Zoology, reported so many of the frogs near Tioga Pass that "[i]t was difficult to walk without stepping on them." Surveys 30 years later revealed the frogs were gone.

The Service acknowledges that the frog has disappeared from the vast majority of known historical locations in the Sierra Nevada and that many of the largest populations have completely crashed in recent years; one of the largest remaining populations containing more than 2,000 adult frogs in 1996 had been reduced to only two frogs by 1999. Particularly disturbing are recent frog surveys in relatively pristine areas of the Sierra Nevada, in the John Muir Wilderness and Kings Canyon National Park, that revealed an alarming decline of more than 40 percent in the last five to seven years alone. At this rate of decline, scientists are predicting the frog will become completely extinct in the Sierra within decades.

The species is thought to be declining primarily due to predation by nonnative trout — stocked in many high-elevation Sierra lakes by the California Department of Fish and Game — which prey upon tadpoles and juvenile frogs. Other causes include habitat degradation due to livestock grazing and the impacts of drought and environmental changes caused by global warming. Disease has ravaged many frog populations recently; factors such as pesticides, acid precipitation, and increased ultraviolet radiation as a result of ozone depletion likely render frogs much more susceptible to disease. Recent research has linked pesticides that drift from agricultural areas in the Central Valley and other airborne chemical pollutants to adverse impacts to native amphibians in the Sierra Nevada; pollutants can directly kill amphibians, interrupt breeding and feeding activity and larval development, and also act as environmental stressors, which render amphibians more susceptible to disease.

The Center for Biological Diversity and Pacific Rivers Council submitted a formal petition to list the mountain yellow-legged frog in February 2000 and subsequently filed suit in May 2001 to compel the service to respond to the listing petition. In December 2001 the Service was ordered by the Northern District Court to make a final listing determination for the species, resulting in the first “warranted but precluded” determination in January, 2003.

A new genetic study of mountain yellow-legged frogs published in 2007 shows that there are two distinct species: one in the northern and central Sierra Nevada, and one in the southern Sierra Nevada and southern California. These distinct species have no range overlap and do not interbreed. Surveys since 1995 at 225 historic yellow-legged frog localities show extinction of 93% of the northern and central Sierra populations, and 95% of the southern Sierra and southern CA populations. Mountain yellow-legged frogs in southern California, which are geographically separated from frogs in the southern Sierra Nevada, are already listed as endangered. The new genetic information and resurvey efforts show that all three populations of both species should be listed as endangered.

Go back