Scientists: Endangered frog rebounding in Yosemite park (Update)

October 3, 2016 by Scott Smith

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, said 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, said Knapp, who charted the frog's rebound in a study published Monday in the Proceedings of the National Academy of Sciences.

"It's got a long way to go to get to where it was," he said. "It's certainly an important milestone."

Park officials stopped stocking non-native fish in some Yosemite lakes, helping the comeback, and it appears that the frog has developed a resistance to the disease deadly to amphibians, called the chytrid fungus.

The disease has led to the extinction of more than 200 species of amphibians around the world in the last 30 years, Knapp said.

The frog's ability to develop a resistance, combined with better management practices, could reverse the decline of amphibians elsewhere, researchers say.

The rebound of the yellow-legged frog is limited to Yosemite, which makes up 13 percent of its historical habitat in the Sierra. Researchers say that elsewhere in the range, the frog remains scarce.

It is still protected as a federally endangered species, and state wildlife officials consider it threatened in California.

Yosemite National Park called the rebound a rare success story in the world of endangered species, and one that made them hopeful the yellow-legged frog would eventually come off the endangered list.

"A lot of people think that species linger on this list in perpetuity and we very rarely see species coming off the list," said Rob Grasso, the park's aquatic ecologist.

"This shows it can be done, and even such an imperiled species as the Sierra Nevada yellow-legged frog can recover when the odds are highly stacked against it," Grasso said. "One day, it could be off the list. This gives us tremendous hope."

Explore further: Long missing frog, turtle species making return to Yosemite

More information: Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors, PNAS,

Related Stories

Rescue and recovery effort for endangered frog

December 22, 2015

Aiming to rebuild rapidly disappearing populations of a California native frog species, scientists from UC Santa Barbara are collaborating with wildlife agencies and two zoos in a unique rescue effort.

Climate change effects on imperiled Sierra frog examined

December 11, 2008

Climate change can have significant impacts on high-elevation lakes and imperiled Sierra Nevada Yellow-legged frogs that depend upon them, according to U.S. Forest Service and University of California, Berkeley, scientists.

Recommended for you

Galactic center visualization delivers star power

March 21, 2019

Want to take a trip to the center of the Milky Way? Check out a new immersive, ultra-high-definition visualization. This 360-movie offers an unparalleled opportunity to look around the center of the galaxy, from the vantage ...

Physicists reveal why matter dominates universe

March 21, 2019

Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Oct 03, 2016
What no pictures of said endangered frog?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.