A giant leap for Southern California’s yellow-legged frogs

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Southern California’s cascading mountain streams were home for thousands of years to yellow-legged frogs. Until very recently, however, an estimated 122 of their descendants were believed to be clinging to existence in eight isolated wild populations of the critically endangered species.

On June 10, U.S. Geological Survey field biologist Elizabeth Gallegos stumbled upon an adult female yellow-legged frog in a remote stretch of Tahquitz Creek in the San Jacinto Wilderness near Idyllwild, where the amphibian was last seen half a century ago.


‘I saw it sitting on a rock,’ she recalled. ‘It leaped into a pool and I thought, Oh my gosh. It’s a yellow-legged frog!’

On June 25, another yellow-legged frog was sighted 2 1/2 miles away from the location by Drew Stokes, a field biologist with the San Diego Museum of Natural History. ‘I carefully reached for my camera,’ Stokes said, ‘and was able to take one photograph before it hopped into the water.’

Now, biologists across the nation are heralding the rediscovery of yellow-legged frogs in the San Jacintos as an important leap forward for a species decimated by an array of threats: firestorms, mudslides, pesticides, hungry trout, fungal infections and loss of habitat as a result of development.

In a statement, Adam Backlin, a USGS scientist who led the survey team that spotted the first new Tahquitz Creek frog, said, ‘If this population is large, it could play an important role in the reestablishment of this species across Southern California.’

The rediscovery is also a boon for an ongoing collaborative effort of government and nonprofit partners to increase the number of frogs in their native habitat, and in captive breeding programs designed to return eggs and tadpoles to places where they stand a good chance of morphing into juveniles.

The San Diego Zoo’s Institute for Conservation Research was first to successfully breed a yellow-legged frog in captivity. The zoo’s breeding program was launched with 82 tadpoles rescued from a drying creek in the San Bernardino National Forest.

Now the institute has dozens of frogs including females, each capable of laying 200 to 300 eggs. ‘It’s all good news because we are losing populations of this animal so quickly,’ said Jeff Lemm, the institute’s research coordinator. ‘Our frogs are expected to breed in the spring.’

The Los Angeles Zoo is planning to start its own captive breeding program with 11 of the institute’s frogs.

In the meantime, federal wildlife authorities are ‘undertaking measures to reduce the impact of human activities where the yellow-legged frog is still found,’ said Jane Herndon, a spokeswoman for the U.S. Fish and Wildlife Service.

‘The discovery in the San Jacinto Mountains coupled with the successful breeding program is a really big deal,’ Herndon added. ‘It gives us hope that we are on the right track and may see this species coming back within its historical range.’

-- Louis Sahagun