Four California Foothill Yellow-legged Frog Populations Protected Under Endangered Species Act

“This is a lifeline for these diminutive lemon-legged frogs, which are an integral part of stream ecosystems along California’s coast and the Sierra foothills,” said Jeff Miller, a senior conservation advocate at the Center. “Protecting these frogs will benefit the rivers and creeks they need to survive and will guarantee clean water for people, too.”

The Service protected frog populations in the Southern Sierra Nevada and South Coast as endangered, and populations in the North Feather River and Central Coast as threatened. A separate frog population in the Northern Sierra Nevada is not proposed for federal protection but was listed as a state threatened species in 2019.

Foothill yellow-legged frogs are stream-dwelling amphibians that have disappeared from more than half of their historic California habitats. These frogs were formerly found in many streams and rivers along the lower western slopes of the Sierra Nevada as well as in Pacific Coast drainages from the Oregon border to at least as far south as Los Angeles County.

The frogs are threatened by a wide range of activities that damage their habitat, including dams and water diversions that alter stream hydrology, high-severity wildfires, flooding, logging, mining, livestock grazing, urban development and marijuana cultivation. They are also harmed by invasive species, climate change, disease and pesticide use.

Background

Adult foothill yellow-legged frogs (Rana boylii) are from 1.5 to 3 inches long, with a distinctive lemon-yellow color under their legs. They inhabit partially shaded, rocky streams that flow year-round, and their life cycle is synchronized with the seasonal timing of streamflow conditions. These frogs need perennial water where they can forage through the summer and fall months.

The Southern Sierra frog population ranges from the South Fork American River watershed, south through the Sierra foothills to the Tehachapi Mountains. The genetically unique Feather River frog population is primarily in Plumas and Butte counties. At least half the known historical frog populations have been lost in every northern and central Sierra Nevada county except for Plumas. Healthy frog numbers remain in the northern and central Sierras in the American, Clavey, Cosumnes, Feather, Merced, Mokelumne, Stanislaus, Tuolumne and Yuba rivers.

The Central Coast frog population inhabits streams in the East Bay and south of San Francisco Bay in the Coast Ranges to San Benito and Monterey counties, where significant numbers remain in the Diablo Range. The South Coast frog population is west of the Salinas Valley in Monterey County and south into the southern Coast Ranges. They have been extirpated from all coastal streams south of San Luis Obispo County.

In 2012 the Center petitioned to protect the foothill yellow-legged frog under the federal Endangered Species Act and in 2016 for protection under the California Endangered Species Act. The California Fish and Game Commission in 2019 listed the Southern Sierra, Central Coast and South Coast populations as endangered, and the Northern Sierra and Feather River populations as threatened. Both federal and state wildlife authorities have determined that foothill yellow-legged frogs in California’s North Coast and Oregon do not currently warrant protection.


[Photo: Foothill yellow-legged frog. Credit: Amy Lind.]


The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.


https://biologicaldiversity.org/w/news/press-releases/four-california-foothill-yellow-legged-frog-populations-protected-under-endangered-species-act-2023-08-28/