Rare Frog Population Increasing in Santa Monica Mountains

Frogs, like this rare red-legged frog, are considered an indicator species that provides information about habitat health. Photo courtesy NPS

Excited shouts, high fives and elated tears erupted among National Park Service (NPS) researchers surveying a stream recently, when they spotted signs of California red-legged frog reproduction. The nine egg masses found are the first known evidence in recent times of the species sustaining a population in the Santa Monica Mountains National Recreation Area (SMMNRA) without the help of humans.

These frogs, popularized by Mark Twain in the 1865 story, “The Celebrated Jumping Frog of Calaveras County,” are listed as threatened under the Endangered Species Act and has not been seen in the Santa Monica Mountains since the 1970s. A population discovered in the nearby Simi Hills in 1999 has been used to replenish the species in four spots in the mountains over the past four years. The idea was that translocated populations would eventually mature, mate and reproduce on their own. The sighting, on March 14, at an undisclosed location, confirmed that the project is headed in the right direction.

“I was literally crying when the stream team showed me the photos of egg masses,” exclaimed Katy Delaney, a NPS ecologist with SMMNRA. “The years of work we’ve put in is showing amazing progress.”

“When I heard the news that California red-legged frogs were breeding at one of the translocation sites, I was beyond thrilled. This success shows how collaborative, voluntary partnerships are truly making a difference for rare, native wildlife in Southern California,” said Chris Dellith, senior fish and wildlife biologist with the U.S. Fish and Wildlife Service’s Ventura Fish and Wildlife Office, which expanded translocation efforts beyond NPS lands to state parks in the Santa Monica Mountains through a Safe Harbor Agreement.

Such agreements provide the opportunity for private and non-federal landowners to proactively support the recovery of rare wildlife by restoring or managing habitat, with assurances that other land uses are not restricted.

Delaney and the team will continue to translocate egg masses from the Simi Hills source population at least until next spring, then monitor the population along with other aquatic species annually as part of a long-term monitoring protocol.

Partners in the reintroduction project are California State Parks, the Mountains Recreation and Conservation Authority, the U.S. Fish and Wildlife Service, the Santa Monica Bay Restoration Commission, the Santa Barbara Zoo, and U.S. Geological Survey (USGS).

The public is also being asked to continue stewardship of their public lands by treading lightly around aquatic habitat. Hiking at the edge of water features, such as waterfalls, streams and ponds, can create erosion, which could dam and dry out areas downstream.

California red-legged frogs (Rana draytonii) require deep pools of year-round water, not easy to find in the arid climate of the Santa Monica Mountains. Many of the streams in the Santa Monica Mountains are infested with non-native species, especially crayfish that prey on frog eggs and tadpoles.

Because frogs are considered an indicator species that provides important information about habitat health, USGS has documented precipitous declines nationwide among amphibians, which may be linked to habitat loss, invasive species and pollution.


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