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For Immediate Release, June 28, 2010

Contact: Jeff Miller, Center for Biological Diversity, (510) 499-9185

California to Consider Endangered Species Act Protection for Imperiled Mountain Yellow-legged Frogs

SAN FRANCISCO  In response to a Center for Biological Diversity petition, the California Department of Fish and Game last week recommended that the state formally evaluate the status of the highly imperiled mountain yellow-legged frog and consider listing the species as endangered or threatened under the California Endangered Species Act. Mountain yellow-legged frogs live in high-elevation lakes, ponds and streams in the Sierra Nevada Mountains and Transverse Ranges of California.

“With this recommendation, the mountain yellow-legged frog has a glimmer of hope for survival and recovery,” said Jeff Miller, conservation advocate with the Center. “Once the most abundant amphibian in the High Sierra, the mountain yellow-legged frog could be restored to its former glory with protection under the California Endangered Species Act.”

Only part of the population of Southern California mountain yellow-legged frogs is currently protected as endangered under the federal Endangered Species Act. In 2000, the Center for Biological Diversity petitioned for endangered status for the Sierra Nevada mountain yellow-legged frog. Although the U.S. Fish and Wildlife Service determined that population also warrants endangered status, the agency refused to confer federal protection, instead placing the Sierra population on the candidate list.

Just a few decades ago, mountain yellow-legged frogs were abundant around many of the Sierra’s alpine lakes. These hardy survivors of freezing Sierra winters are vulnerable to a host of modern threats that have driven the species to the brink of extinction. Surveys since 1995 show that 93 percent of the northern and central Sierra frog populations and 95 percent of southern frog populations have been lost. Both frog populations are on a rapid trend to extinction due to predation by introduced trout, spread of diseases that may be exacerbated by pesticide exposure, habitat alterations caused by both development and climate change, drought and livestock grazing.

The California Fish and Game Commission will vote at its August 5 meeting on whether to accept the listing petition and initiate a year-long formal status review of both the Southern California and Sierra Nevada species of mountain-yellow-legged frog. Public comments to the Commission regarding the need to list this imperiled species can be provided at the August 5 meeting; written comments should be sent by July 26.

The Center has twice sued the California Department of Fish and Game to force evaluation of the environmental impacts of the state’s fish-stocking program. In January the Department released a flawed environmental impact report on the effects of stocking hatchery fish on native fish and amphibians. The Center sued Fish and Game again in February since the state has failed to adopt adequate measures to reduce the harm from fish stocking to mountain yellow-legged frogs and other imperiled aquatic species.

The Center for Biological Diversity is a national nonprofit conservation organization with more than 255,000 members and online activists dedicated to the protection of endangered species and wild places.


Mountain yellow-legged frogs are adapted to high-elevation habitats without aquatic predators. Widespread stocking of nonnative trout in high-elevation Sierra lakes by the California Department of Fish and Game has been the primary cause of decline of the species. Introduced trout prey on tadpoles and juvenile frogs and change the food web of the aquatic ecosystems on which frogs depend. Since 2000, the National Park Service and U.S. Forest Service have begun removing nonnative trout from some high Sierra lakes on federal lands in an attempt to restore yellow-legged frog populations.

In 2006 the Center for Biological Diversity filed suit against Fish and Game for failing to complete an environmental review of the impacts of fish stocking on sensitive aquatic species; in 2007 a court ordered the state agency to conduct a public review of the stocking program’s impacts. In 2008 Fish and Game agreed to interim restrictions prohibiting stocking trout in water bodies with species sensitive to nonnative fish. In 2010 Fish and Game released a flawed environmental impact report regarding the fish stocking program, leading to another Center lawsuit in February. Although the state has taken some steps to reduce trout stocking in areas with yellow-legged frogs, stocked trout continue to harm frog populations and limit recovery. Permanent protection and management decisions to stop stocking and remove trout in key frog habitats are necessary to reduce trout predation of mountain yellow-legged frogs.

Recent research has linked pesticides that drift from agricultural areas in the Central Valley to declines of native amphibians in the Sierra Nevada. Pesticides and other pollutants can directly kill frogs and also act as environmental stressors that render amphibians more susceptible to diseases, including a chytrid fungus that has recently ravaged many yellow-legged frog populations.

Mismanagement of national forest lands has degraded frog habitat where livestock grazing, logging, off-road vehicles and recreational activity are allowed in frog habitat. Rapid climate change has brought warmer temperatures, decreases in runoff, shifts in winter precipitation in the Sierra from snow to rain, and habitat changes that are rendering frog populations more vulnerable to drought-related extinction events.

The mountain yellow-legged frog was recently re-described by scientists as two distinct species: the southern mountain-yellow-legged frog (Rana muscosa), which occurs in the southern Sierra and Transverse Ranges of Southern California; and the Sierra Nevada mountain yellow-legged frog (Rana sierrae), inhabiting the central and northern Sierra.

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