The amazing recovery of Yosemite’s yellow-legged frog

Date: October 5, 2016

Source: University of California, Santa Barbara

They say what doesn't kill you makes you stronger.

That old adage appears to hold true for the endangered Sierra Nevada yellow-legged frog (Rana sierrae), whose remarkable recovery in the face of myriad threats has now been documented in an expansive, data-rich study of the species in Yosemite National Park.

New research from UC Santa Barbara biologist Roland Knapp and colleagues shows that after decades of decline -- and despite continued exposure to stressors including non-native fish, disease and pesticides -- the frog's abundance across Yosemite has increased seven-fold, and at an annual rate of 11 percent, over the 20-year study period.

Those increases, occurring over a large landscape and across hundreds of populations, Knapp said, provide a rare example of amphibian recovery at an ecologically relevant scale. The findings appear in the early online edition of the Proceedings of the National Academy of Sciences.

"We now have a parkwide picture of what's happening in Yosemite, and it shows convincingly that these frog populations are increasing dramatically, " said Knapp, based at UCSB's Sierra Nevada Aquatic Research Laboratory in Mammoth Lakes. "These new results show that, given sufficient time and the availability of intact habitat, the frogs can recover despite the human-caused challenges they face."

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