California red-legged frogs may be an endangered species, but those in the Santa Monica Mountains of California are also proving to be a resilient species. While the Woolsey Fire swept most of the Santa Monica Mountains National Recreation Area in November 2018, two separate populations of the frogs became found in the fire-scorched area.
According to park biologists, there have been no wild red leg frogs at these locations for perhaps 50 years
During recent stream surveys, researchers discovered three egg masses in a Los Angeles County location. At another location in Ventura County, biologists found a female and a male frog, and then, a week later, voila – a single egg mass. This was proof that the frogs successfully brooded on their own. All egg masses have successfully hatched since then.
“It was a welcome surprise,” said Katy Delaney, an ecologist at the Santa Monica Mountains National Recreation Area who has led the project for a decade.
In 2014, NPS biologists established two river sites to reintroduce the species to the Santa Monica Mountains. Two years later, egg masses were reintroduced at two other brook locations. These are the two websites that are currently experiencing new activity.
A population discovered in the nearby Simi Hills was used to repopulate these four mountain locations. Translocated eggs were raised into tadpoles and released into the four streams. The idea was that translocated individuals would eventually mature, mate, and reproduce on their own.
The project was buzzing before the Woolsey Fire in November 2018. Frogs survived in each of the four streams – from tadpoles to adult adults. The adult adults of the first two reintroduction pens had already started to reproduce on their own. For the two newer pages it was still a little early to be reproduced.
The wildfire was followed by catastrophic mudslides that wiped out much of the frog’s habitat. The frogs require deep breeding tanks with year-round water and foliage that are not easy to find in the arid Santa Monica Mountains. Many streams have been filled in with mud, mud, and debris.
Since frogs are picky about where to reproduce, Delaney had doubts about their future, and therefore about the future of their project.
She wondered if this could be the end of these newly established populations of nocturnal amphibians. However, she is pleased that the frogs have proven to be more resilient than she initially thought.
“Here we are two years later, and the streams have recovered enough to create ponds that the frogs must have liked,” Delaney said.
The exception is one of the resettlement sites introduced in 2014. The habitat is in poor condition and very few frogs have been studied, the researchers said. Frogs bred there before the Woolsey Fire, but not since then.
Regardless of this, biologists see this latest development as a positive milestone for the project, since wild game breeding has been successfully carried out at every release point.
“This is another step towards our goal of self-sustaining the populations of these frogs in our region,” said Delaney.
Biologists regularly conduct examinations for tadpoles. They will be looking for frogs later this summer.
The last known record of California red leg frogs in the Santa Monica Mountains dates back to the 1970s. As a result, they are classified as threatened nationwide under the Endangered Species Act and are a particularly worrying state species.
California State Parks, the Mountains Recreation and Conservation Authority, the Santa Barbara Zoo, the Santa Monica Bay Restoration Commission, the Santa Monica Mountains Conservancy, the California State Coastal Conservancy, the US Fish and Wildlife Service, and the USA Geological Survey are partners in the reintroduction project (USGS).