SACRAMENTO, Calif. (CN) – After vanishing from nearly half of their historic habitat, six populations of imperiled yellow-legged frogs will get new protections following a decision by the California Fish and Game Commission.
"This is really good news for these iconic but highly imperiled stream-dwelling frogs," said Jeff Miller, a conservation advocate with the Center for Biological Diversity.
The center filed a petition with the state in 2016 seeking protection for several populations of the frogs, named for the distinctive lemon-yellow color beneath their hind legs.
The commission voted unanimously Wednesday to classify the Southern Sierra, Central Coast and South Coast populations of the frog as endangered. The Northern Sierra and Feather River populations will be classified as threatened. The commission decided the foothill yellow-legged frogs in California’s North Coast do not currently warrant protection.
Once so plentiful that dozens of frogs would hop away with each step of an approaching person, the frog's Sierra Nevada population saw declines as steep at 90% due in part to non-native trout invading their habitats and a disease called chytrid fungus, which is deadly to amphibians.
In 2016, scientists announced a new vaccine against the deadly fungus, which has killed more than 200 species of amphibians across the globe over the last three decades. Officials at Yosemite National Park also stopped stocking non-native fish in some lakes, which has helped to the frog fight its way back from extinction, according to researchers.
The U.S. Fish and Wildlife Service in 2016 designated more than 1.8 million acres spanning 16 counties as critical habitat for the Yosemite toad, Sierra Nevada yellow-legged frog and northern distinct population segment of the mountain yellow-legged frog.
This year, a federal judge rejected a challenge to the frog's critical habitat designation brought by farming and ranching industry groups. U.S. District Judge Trevor McFadden in Washington found the groups' lawsuit was based on "hypothetical future harm that is not certainly pending.”
Though U.S. Fish and Wildlife has classified the Sierra Nevada yellow-legged frog as endangered, it has yet to render a decision on a 2012 petition seeking Endangered Species Act protection for the foothill yellow-legged frog. Under a settlement reached with the Center for Biological Diversity, Fish and Wildlife has vowed to decide by 2020 whether the foothill population warrants federal protection.
Foothill yellow-legged frogs face a wide variety of threats, including dams, water diversions, logging, mining, livestock grazing, climate change, pesticides, off-road vehicles, disease, urban and agricultural expansion and marijuana cultivation, according to the center.
Ranging in length from 1.5 to 3 inches long, adult yellow-legged frogs (Rana boylii) prefer to live in partially shaded, rocky perennial streams. Their life cycles are tied to the seasonal timing of stream flow conditions, and they require perennial water so they can forage in the summer and autumn months to survive.
At least half of the historical yellow-legged frog populations have disappeared from every northern and central Sierra county except Plumas County. Healthy frog populations remain in the northern and central Sierras in the American, Clavey, Cosumnes, Feather, Merced, Mokelumne, Stanislaus, Tuolumne and Yuba rivers, according to the center.
The frog's South Coast population, which lives west of the Salinas Valley in Monterey County into California's southern coastal ranges, has vanished from all coastal streams south of San Luis Obispo County.
"Protecting them will also help safeguard beautiful coastal and Sierra foothill streams which we all rely on for clean drinking water and recreation, said Miller, of the Center for Biological Diversity.