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For Immediate Release, February 2, 2012

Contact: Jeff Miller, (415) 669-7357

California Protects Vanishing High Sierra and Southern California Frogs
Under State Endangered Species Act

SACRAMENTO, Calif.The California Fish and Game Commission voted unanimously today to designate two species of native frogs inhabiting high-elevation lakes in the Sierra Nevada and Southern California mountain ranges as threatened and endangered species under the state’s Endangered Species Act. More than 75 percent of the state’s high-elevation frog populations have disappeared because of introductions of nonnative trout, disease and pesticides. Sierra mountain yellow-legged frogs are now protected as threatened species and Southern mountain yellow-legged frogs are designated as endangered.

“With formal state protection, California can start recovering an important part of mountain ecosystems to bring back formerly abundant amphibians,” said Jeff Miller at the Center for Biological Diversity, which petitioned for state protection in 2010. “Taking out exotic trout and getting rid of pollutants to restore mountain yellow-legged frogs will have ripple effects beyond these species — it’ll help to heal some of the damaged high-elevation habitats of the Sierras and Southern California mountains.”

Following the Center’s petition, in 2011 the state’s Department of Fish and Game completed an evaluation of the status of both species and recommended threatened and endangered listings, respectively, for Sierra and southern frogs.

The Center originally petitioned to protect the Sierra frog population under the federal Endangered Species Act in 2000. Mountain yellow-legged frogs in Southern California were protected as a federal endangered species in 2002, but although the U.S. Fish and Wildlife Service determined Sierra frogs also deserved endangered status, it instead placed them on an indefinite waiting list. A recent settlement agreement with the Center, which will also speed protection decisions for 756 other species, requires the Service in 2013 to make a decision about whether to add the Sierra frog to the federal endangered list.

Just a few decades ago, mountain yellow-legged frogs were abundant around many of the Sierra’s alpine lakes. Tadpoles must survive up to four freezing winters at the bottom of deep lakes before metamorphosing. These hardy frogs are vulnerable to predation by introduced trout and diseases that may be exacerbated by pesticides; other threats are habitat changes caused by water developments, climate change and livestock grazing. More than half of frog populations found in 1995 have now gone extinct.

The new state listing makes it unlawful to “take” (defined as killing, harming or capturing) frogs without state authorization. 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, which introduces exotic trout into the high-elevation habitats where species such as the mountain-yellow-legged frog evolved without aquatic predators. The Department is recommending no trout stocking in the state without a fish management plan, and no further stocking of trout in areas that would conflict with protecting yellow-legged frogs.

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

Widespread stocking of nonnative trout in high-elevation Sierra lakes has been a primary cause of the species’ decline. Introduced trout eat tadpoles and juvenile frogs and change the food web of the aquatic ecosystems on which the native frogs depend. Since 2000, the National Park Service and Forest Service have begun removing nonnative trout from some high Sierra lakes on federal lands in an attempt to restore yellow-legged frog populations. The state has taken some steps to reduce trout stocking in areas with endangered frogs; 113 high-elevation lakes in California have been dropped from the stocking program to protect frogs and an additional 504 have been dropped to protect other native species, such as endemic trout. Fish and Game also has 63 ongoing nonnative fish removal projects and is translocating frogs to repopulate former habitats.

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, water diversions, 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.

Read more about the Center’s 757 species settlement and our campaign to save mountain yellow-legged frogs.

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