SAN FRANCISCO— The Center for Biological Diversity today filed a lawsuit over the U.S. Fish and Wildlife Service’s lengthy delay in deciding whether to extend Endangered Species Act protection to the foothill yellow-legged frog, which has disappeared from more than half of its former streams in California and Oregon. This stream-dwelling amphibian faces a host of threats, including impacts from dams and water diversions, logging, mining, livestock grazing, roads, marijuana cultivation, off-road vehicles, climate change, pollution, invasive species and disease.

“Foothill yellow-legged frogs need habitat protections and recovery efforts under the Endangered Species Act to avoid more population declines and stem the risk of extinction,” said the Center’s Jeff Miller. “If we can protect these frogs, it will benefit other wildlife and many river and stream ecosystems in California and Oregon that we already love and rely on for recreation, wilderness qualities, open space and drinking water.”

The 1.5- to 3-inch-long frogs, with a distinctive lemon-yellow color under their legs, live in low-elevation streams in Pacific Coast drainages, from the Willamette River basin in Oregon south to the San Gabriel River in Los Angeles County, Calif., as well as the lower western slopes of the Sierra Nevada mountains. They have disappeared from many portions of their historical range, especially in Southern California and Oregon. Frog populations have declined severely in the southern Sierra Nevada, central California coast, Bay Area, Southern California coast and central Oregon. Each of these areas may contain distinct populations or subspecies of yellow-legged frogs.

The Center petitioned in 2012 for protection of the foothill yellow-legged frog under the Endangered Species Act. In July 2015 the Fish and Wildlife Service determined that the species may warrant protection and initiated a formal status review. In August 2015 the Center submitted extensive information on declines of frog populations, demonstrating that the species should be protected. The Service is now more than three and a half years overdue in determining whether the frog should have the Act’s protection.

“With nearly a third of the world’s amphibians in danger of extinction, we should be paying attention and taking action when one of our native frogs is in rapid decline,” said Miller.

The foothill yellow-legged frog (Rana boylii) is nearly extirpated from the entire Willamette River drainage in central Oregon. The species has also declined in southwestern Oregon and the Umpqua River drainage, and may be extirpated from the upper Klamath River basin.

California’s northern coast ranges are the species’ stronghold. Although there have been some declines, healthy frog populations remain in the Smith, Klamath, Trinity, Eel and Russian river drainages, as well as Redwood Creek in Humboldt County and coastal tributaries in Mendocino County.

Frogs have declined severely in the central Sierra Nevada foothills, but populations still can be found in the Rubicon, American, Yuba and Feather river drainages, as well as Spanish Creek and Canyon Creek. They are nearly extirpated from the southern Sierra Nevada and are gone from Yosemite, Sequoia and Kings Canyon national parks.

There have been severe declines of frogs in the Bay Area and central California coast among populations in Sonoma County and the Diablo Range. The species is nearly extirpated from the south-central California coast and has been eliminated entirely from streams in Southern California and Baja California.

The foothill yellow-legged frog is one of 10 species the Center is prioritizing this year for Endangered Species Act protection decisions. Under a 2011 settlement agreement with the Service, the Center can seek expedited decisions on protection for 10 species per year. The other nine priority species for 2016 include the monarch butterfly, California spotted owl, Northern Rockies fisher, alligator snapping turtle, wood turtle, Virgin River spinedace, Canoe Creek pigtoe, Barrens topminnow and beaverpond marstonia. Under the settlement 144 species have gained protection to date, and 36 species have been proposed for protection.