A distant lakeshore inside Yosemite National Park teems with life: coyotes, snakes, birds, tadpoles, frogs. Frogs are at the guts of the scene, which was very different a decade ago. It was quiet — and never in an excellent way. The frogs which are central to this ecosystem were missing, worn out by a deadly fungal disease referred to as amphibian chytrid fungus.
Now, because of the continued and focused efforts of researchers and conservationists to rescue, then reintroduce, mountain yellow-legged frogs to this and a number of other other lakes in Yosemite, their populations are once more thriving.
A brand new landscape study led by UC Santa Barbara (UCSB) biologist Roland Knapp, with colleagues from UCSB, the University of Colorado, Boulder, the University of Tennessee, and Yosemite National Park, details the long-term effort. Including 24 reintroductions in 12 different regions. Over 17 years of web sites in Yosemite. During this time, remarkably, the frogs have developed some resistance to the chytrid fungus, allowing them to persist in its presence. The paper has now been published within the journal Nature Communications.
“Going back to some of the lakes where the frogs are recovering now, and just sitting and watching reminds you of what's been done,” said Knapp, who relies at UCSB's Sierra Nevada Aquatic Research Laboratory. ” “You're sitting on the bank and there's tadpoles within the water throughout you and there's adult frogs sitting on the shore with you. You've got birds flying around and eating them, and snakes crawling on them. You have a lake that comes back to life.”
As it has done to amphibians world wide, it has decimated the native frog population in Yosemite. Once essentially the most common amphibian within the high-elevation portion of California's Sierra Nevada Mountains, the Sierra Nevada yellow-legged frog () has disappeared from greater than 90 percent of its historic range over the past century. It is currently listed as “endangered” under the Endangered Species Act. But of their long-term study, Knapp and co-researchers were in a position to successfully re-establish breeding populations by moving resistant frogs to sites where the species had been worn out. The success of their recovery efforts is a ray of hope for amphibian conservation.
“In our study, the results of viable modeling show that many reintroduced populations are likely to persist for more than 50 years,” Knapp said. “These findings provide a rare example of how the reintroduction of resistant individuals can allow the recovery of disease-affected species on land, and have broad implications for amphibians and many other taxa. which are threatened with extinction by novel pathogens.”
Amphibians are essentially the most threatened vertebrate class, with greater than 40% of species susceptible to extinction. In lower than a generation, the emergence of the amphibian chytrid as human
The fungus (Bd) has devastated global amphibian biodiversity, with hundreds of populations declining or extirpated, and dozens of species now extinct within the wild. Even amphibians in essentially the most protected habitats have fallen victim to what Knapp calls the “invisible killer.”
All of this makes the study's success much more “mind-blowing,” he said. “It's mind-blowing where we were 10 or 15 years ago, when we weren't sure if we were going to have this frog in the landscape anymore, to see how things are changing. To see that. Unbelievable.”
It's taken some seriously labor to get here.
Reintroduction requires careful planning. When identifying optimal sites for reintroduction, team members should consider site elevation, winter severity, and predation risk. And monitoring migratory frogs is an intensive, long-term effort, often requiring researchers to go to and capture each frog at a site several times a 12 months.
By monitoring these translocated populations over several years, the team observed the recruitment of recent adult frogs, indicating successful recovery. Held inside the protected confines of a national park, their efforts, Knapp noted, show the importance of maintaining and restoring natural processes in these ecosystems.
What about the potential for expanding this approach across the Sierra Nevada range — whilst a proof of concept, and possibly as a model, of comparable conservation world wide? For efforts?
“Having that broader perspective is really important,” Knapp said. Allowing to do. This frog, which was pushed to the brink of extinction by this pathogen, is now becoming one. An example of how we are able to restore amphibians world wide.”
Knapp's co-authors on the study are Mark Wilber on the University of Tennessee Institute of Agriculture; Maxwell Joseph, of CU Boulder and Planet; Thomas Smith, also of UC Santa Barbara; and Robert Grasso in Yosemite. Funding for the project was provided by the Yosemite Conservancy, the National Park Service and the National Science Foundation.