3 California Frogs Win Protection Under Endangered Species Act

A female Yosemite Toad | Photo: Natalie McNear/Flickr/Creative Commons License

Good news for frogs and their admirers: the U.S. Fish and Wildlife Service has granted protection to three species of frogs in California -- or more precisely, two frogs and a toad -- under the U.S. Endangered Species Act.

On Friday, USFWS announced it had ruled it would list the Sierra Nevada yellow-legged frog, along with a population of the mountain yellow-legged frog, as endangered under ESA. USFWS will also be listing the Yosemite toad as Threatened.

All three species are found in high-elevation lakes and streams in the Sierra Nevada that historically had no fish populations, and all three have been seriously harmed by California's stocking of those lakes with trout for sportfishing.

The listings resolve the cases for three more species included in a 2011 agreement between USFWS and the Center for Biological Diversity that the agency would make listing decisions on a backlog of 757 species that had been languishing in "candidate" status.

The Sierra Nevada yellow-legged frog (Rana sierrae) and the mountain yellow-legged frog (Rana muscosa) are very similar in appearance, close enough so in fact that until 2008 they were considered to belong to the same species. They grow to just under four inches long at their maximum with appealingly mottled brown and light markings on their tops, and pale orange or yellow undersides that give them their common name.

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Sierra Nevada yellow-legged frogs range through the mountains for which they're named from Lake Almanor in Plumas County south to Kings Canyon National Park. The northern population of the mountain yellow-legged, which was listed Friday as a Distinct Population Segment (DPS), legally equivalent to a species for ESA purposes, ranges from Kings Canyon south to the southern end of the Sierra.

The Southern DPS of the mountain yellow-legged frog, whose range is in the San Gabriel, San Bernardino, and San Jacinto mountains, has been listed as Endangered since 2002. Fewer than 100 adults are thought to remain in the wild, despite the fact that the mountain yellow-legged frog was once the most common amphibian on those mountain ranges.

As for the Yosemite toad, Anaxyrus canorus, the new addition to the Threatened species list is an unprepossessing little toad that lives in Sierra forests from Ebbetts Pass to Kings Canyon. A true toad, it lives its adult life out of the water but returns to creeks and ponds, and snowmelt-flooded meadows to breed, making its eggs and tadpoles vulnerable to those planted trout. Maxing out at just under three inches long, male Yosemite toads are pale yellow-green to olive above with lighter countershading below, while the females have striking and distinctive dark mottling above.

In addition to predation by introduced fish, Yosemite toads are thought to suffer from increased raven populations, grazing in the mountains, pesticide drift from Central Valley farms, and drought. It's thought that the species has lost 50 percent of its range over the 20th Century.

Though USFWS has proposed 1,831,820 total acres of critical habitat for the three frogs, that designation has already generated controversy among Sierra Nevada business interests. A final ruling isn't expected until next year.

Still, good news on a Friday for some of California's most threatened amphibians.

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

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