Project overview: Restore native amphibian populations, including by reintroducing Sierra Nevada yellow-legged frogs, California red-legged frogs, and Yosemite toads to healthy lakes and meadows.

How your support helps: Amphibian populations are threatened around the globe, as habitats are destroyed or deteriorate, and invasive diseases (such as chytridiomycosis) and species arrive. Since the late 1990s, our donors have supported efforts to study and save Yosemite’s native amphibians through surveys of lakes, ponds, and meadows; and ambitious captive rearing and reintroduction efforts. In recent years, donor-funded work has focused on three imperiled amphibians: Yosemite toads, Sierra Nevada yellow-legged frogs, and California red-legged frogs.

  • Yosemite toads: Through Conservancy-supported research, scientists have increased their understanding of the park’s population of Yosemite toads, a rare and endemic species.
  • Yellow-legged frogs: Starting in 2013, the Conservancy began funding targeted efforts to restore high country lakes and reintroduce once-common, now-endangered Sierra Nevada yellow-legged frogs. That effort has resulted in a measurable increase in yellow-legged frog numbers in Yosemite, one of few examples of a frog population rebounding as amphibians decline worldwide.
  • Red-legged frogs: In 2016, with support from donors, scientists turned their attention to another imperiled amphibian, California red-legged frogs, which hadn’t been seen in the park in half a century. In recent years, biologists have reintroduced thousands of red-legged frog eggs, tadpoles, and adults in Yosemite Valley, where the species is now successfully reproducing and regaining a foothold in the ecosystem.

The park’s successful amphibian work is anchored in innovative approaches to wildlife research and restoration. With donor support, scientists have been able to identify healthy habitat using environmental DNA (eDNA) techniques; study the prevalence of chytrid fungus, which causes the potentially deadly amphibian disease chytridiomycosis; use tiny microchips to monitor red-legged frogs; partner with the San Francisco Zoo to raise young amphibians in a protected space; and more.

This year: Through this 2022 grant, scientists are continuing the critical work of restoring and protecting native frogs and toads, ensuring that populations are healthy, resilient, and growing. This year, park teams will introduce foothill yellow-legged frogs for the first time to their native habitat in Yosemite Valley and El Portal.

Biologists will also prepare to release Yosemite toads — which Conservancy-funded research identified as particularly vulnerable to drought and climate change — for the first time to their native habitat in park meadows. A reintroduction has never been attempted with Yosemite toads; if successful, this effort could set the stage for additional work to save the species.

Project partners: Yosemite National Park; University of California, Santa Barbara; and San Francisco Zoo

Rob Grasso

Aquatic Ecologist, Yosemite National Park

Project Notes

“We are excited to continue our successful species recovery projects. Yosemite is one of the only places in the world where amphibian populations are increasing as a result of adaptive management.”