The Sierra Nevada yellow-legged frog was, historically, a common species inhabiting Yosemite’s meadows. Visitors once joyfully described their encounters with hundreds of frogs basking in the sun near high-elevation mountain lakes. Unfortunately, this keystone species is in danger of becoming extinct.

Park scientists are using promising new technology, called “environmental DNA,” to detect frog predators, such as trout, in Yosemite’s lakes. This minimally invasive survey tool means hard-to-find species can be detected reliably with decreased search efforts and personnel costs. In 2015, with your support, scientists and youth volunteers collected samples from restored alpine lakes in order to monitor the amount of trout DNA and assess habitat suitability for Sierra Nevada yellow-legged frogs.  This innovative technique has the potential to be used in similar work related to endangered or invasive species elsewhere in Yosemite and across the Sierra Nevada. In 2016, for example, scientists are using eDNA to support the restoration of two other water-loving species in Yosemite: the California red-legged frog and the western pond turtle.

Your gift supported important research and restoration work to ensure Yosemite’s endangered frogs and other creatures are protected for the future.

Completed in partnership with Yosemite National Park.

Rob Grasso

Aquatic Ecologist, Yosemite National Park

Project Notes

Environmental DNA (eDNA) is a promising new tool that has the potential to reliably detect trout in lakes, providing a simple means to monitor the success of restoration efforts. New eDNA techniques work to isolate DNA for a target animal from water samples from the lake environment, providing a minimally invasive survey tool with significant decreased personnel costs, when compared with traditional surveys.