Aid Improved for Sierra Nevada Amphibians

WASHINGTON (CN) - Citing the effects of climate change, invasive species and disease, regulators listed three Sierra Nevada amphibians under the Endangered Species Act.

The Center for Biological Diversity and the Pacific Rivers Council had originally petitioned the U.S. Fish and Wildlife Service to list the mountain yellow-legged frog and the Yosemite toad in 2000. Four years later, the two environmental groups legally challenged the agency's "warranted but precluded by higher listing priorities" determination.

Though the court ruled for the agency, a 2006 appellate decision found that the agency's determination did not meet the requirements of the Endangered Species Act.

Announcing the listing of the species late last month, the Center for Biological Diversity attributed the protections to a 2011 agreement "between the center and the service to speed up endangered species protection decisions for 757 imperiled animals and plants around the country."

A recent change in taxonomic classification has resulted in a split within the mountain yellow-legged frog species complex to which the proposed listing regulation referred.

The final regulation lists the Sierra Nevada yellow-legged frog and the northern distinct population segment of the mountain yellow-legged frog as endangered. The Yosemite toad is listed as threatened. The three amphibians are native to the higher elevations in California's Sierra Nevada range.

Fish and Wildlife has estimated that the Sierra Nevada yellow-legs have declined by 70 percent, that the mountain yellow-legs have declined by over 80 percent, and that the Yosemite toad has declined by almost 50 percent.

The frogs are threatened by the introduction of non-native trout into areas that were historically fishless or areas historically populated by smaller fish. One survey noted that the frogs were "five times less likely to be detected in waters where trout were present," according to the action.

Another major threat is a fungus that has attacked amphibian populations worldwide, causing massive die-offs and even extinctions, the regulation states.

These threats, along with habitat fragmentation caused by dams, grazing, roads, recreation and timber harvests, have weakened the frog populations and increased their vulnerability to the effects of climate change.

Since Yosemite toads breed in shallow meadow pools, introduced predatory fish have not so challenged them. They face similar habitat fragmentation threats as the frogs, and they may be even more vulnerable to climate changes that affect snowfall and snowmelt patterns because their pools are not year-round water sources. Changes in soil-moisture levels contribute to the encroachment of trees into the meadow habitats, the action notes.

Drought has caused some toads to switch breeding activities to small streams because of a decrease in the number of meadow pools, which has resulted in their exposure to predatory fish. The same fungus that affects the frogs also affects the toads.

Fish and Wildlife said the critical habitat determination for the amphibians "is expected to be made early next year." Last year's proposal for critical habitat totaled more than 1.8 million acres.

"Once abundant, all three species have been in decline for several decades and are now found primarily on publicly managed lands at high elevations including streams, lakes, ponds, and meadow habitats located within national forests and national parks," the agency said in a statement.

The listings are effective June 30.

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