With support from the Conservancy, scientists have started to bring endangered Sierra Nevada yellow-legged frogs back from the brink of extinction in recent years by moving them to predator-free lakes. In 2016, in addition to expanding those efforts, scientists began restoring the populations of two other native water-loving species: California red-legged frogs and western pond turtles.

Through this grant, park experts, with help from youth volunteers, released a group of adult turtles in the Merced River; before that introduction, the once common species had not been reported in the Valley for more than 50 years. They also released approximately 2,000 red-legged frog tadpoles, which had been absent from Yosemite for a half-century. After the introductions, the team monitored the new Valley residents using radio transmitters (for the turtles) and eDNA sampling (for the tadpoles).

At higher elevations, scientists focused on yellow-legged frogs, introducing the species at two additional lakes and working with volunteers to rescue more than 9,000 tadpoles imperiled by the effects of the multiyear drought.

Your gift helped Yosemite scientists continue to protect frogs and turtles, restore ecosystem balance and ensure future generations will experience the joy of seeing native wildlife. Thank you for supporting your park!

Completed in partnership with Yosemite National Park, Dr. Roland Knapp (University of California, Santa Barbara), California Department of Fish & Wildlife, Student Conservation Association, San Francisco Zoo, U.S. Fish & Wildlife Service, U.S. Forest Service and U.S. Geological Survey. 


Rob Grasso

Aquatic Ecologist, Yosemite National Park

Project Notes

The endangered Sierra Nevada yellow-legged frog has declined drastically in Yosemite over the last two decades. However, past Conservancy-funded research indicates that populations are increasing 10% per year. This year, we reintroduce California red-legged frogs and western pond turtles to Yosemite Valley.