A native California frog once on the brink of extinction is making an encouraging comeback in Yosemite National Park, raising hopes for amphibians like it worldwide that are dying off at an alarming rate, researchers said Monday.
The Sierra Nevada yellow-legged frog — little more than 3 inches long and known for the coloring under its hind legs — was once the most abundant amphibian in the mountain range.
They were so numerous that they bounded by the dozens into lakes and streams with each step of an approaching person, says lead researcher Roland Knapp of the University of California Sierra Nevada Aquatic Research Laboratory.
Their numbers began to plummet roughly a century ago as they were gobbled up by non-native trout stocked for fishing. Disease later struck, removing them from 90 percent of their native habitat in the Sierra, scientists say.
Efforts to save the frog from extinction have led to a sevenfold increase in their numbers in Yosemite in the last 20 years, says Knapp, who charted the frog's rebound in a study published Monday in the Proceedings of the National Academy of Sciences.