Endangered frogs released in the San Jacinto Mountains near Idyllwild

A team of scientists from the San Diego Zoo Wildlife Alliance, University of California, Los Angeles, U.S. Forest Service, California Department of Fish and Wildlife, and the U.S. Fish and Wildlife Service reintroduced a group of 253 endangered mountain yellow-legged frogs to a remote site in the San Bernardino National Forest July 8.

The U.S. Forest Service said the release is the second in several years that will hopefully increase the number of the endangered frogs in the South Fork San Jacinto River east of Idyllwild. The exact location of the drop was not revealed with warnings posted not to disturb their habitat.

The California Department of Fish and Wildlife completed an extensive habitat improvement project at the site to benefit the frogs. An additional release is planned at this site later in July, bringing the total number of juvenile frogs released this year to close to 400.

"The frogs were bred by the San Diego Zoo Wildlife Alliance and are one year old. It is hoped that after completing successful overwintering in their mountain habitat, these frogs, which are a mix of males and females, will survive for the next few years to reproduce and establish a self-sustaining population in this portion of its range," a Forest Service news release said.

For more than 20 years, the U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, U.S Forest Service, U.S. Geological Survey, San Diego Zoo Wildlife Alliance and other partners have worked together on recovery actions for the Southern California population of mountain yellow-legged frogs.

"It will take many partners working together to help us fully restore mountain yellow-legged frogs throughout their Southern California range," Scott Sobiech, Field Supervisor for the U.S. Fish and Wildlife Service's Carlsbad Office, said. "Although the frogs still face many threats, this release is a tremendous example of the progress we are making towards recovery for the frog."

Getting the frogs to the release site involved transporting them by vehicle to a trailhead in special cooler backpacks that maintain a suitable temperature for this high-altitude species, and then making a more than 5-mile hike to the actual release location. Occasional small radio transmitters are attached to the one and one-half to two inch frogs to trace their success and what other fate nature brings to them.

"Climate change and chytrid fungus are creating challenges to mountain yellow-legged frog survival that the species has never faced before," Debra Shier Ph.D., the Brown endowed Associate Director of Recovery Ecology and Southwest hub co-leader, San Diego Zoo Wildlife Alliance, said. "Through our collaborative efforts to create and grow ex-situ insurance populations, to use science to understand and mitigate threats and to develop effective reintroduction strategies, we hope to successfully reestablish the mountain yellow-legged frog in its native habitat and allow the species to play its important role in the ecosystem into the future."

Historically, the Southern California population of mountain yellow-legged frogs was widely distributed across the San Gabriel, San Bernardino, San Jacinto and Palomar mountains. Several factors, including non-native predators, recreation impacts, and disease contributed to the disappearance of the species from most of its habitat by the time it was listed by the Forest Service as an endangered species under the Endangered Species Act in 2002. At the time of listing, the Service estimated there were fewer than 100 adult frogs left in the wild.

Over the years, recovery efforts have included management of lands on Angeles and San Bernardino National Forests to minimize human impacts to habitat; and conservation and research programs by the San Diego Zoo Alliance, U.S. Geological Survey, Los Angeles Zoo, Omaha's Henry Doorly Zoo and Aquarium, Santa Ana Zoo, and UCLA to inform future conservation and management of the species.

"As land managers, our main role is to protect the frogs and their habitat so populations can recover," Kim Boss, district wildlife biologist for the San Jacinto Ranger District, said. "One example is closing populated streams to public entry when frogs are active. We thank the public's continued adherence to the closure so these unique frogs have a fighting chance."  

Often visitors to campground sites may see Forest Service Volunteer Assn. members monitoring the creek to ensure the frogs' safety from human encroachment.

Although much of California is experiencing drought and heightened risk of wildfire, the conditions at the release site in the San Jacinto Mountains remain favorable to support the frogs.

"The Department has spent a lot of time evaluating, permitting and rehabbing release waters and we're optimistic about the location." Russell Black, senior environmental scientist supervisor for the California Department of Fish and Wildlife, said. "It has a large amount of drought resistant habitat that should provide a stable location for these frogs for many years."

The population of frogs across their historic range remains low, and recovery efforts will continue into the future, officials said.

This story is from a combined U.S. Forest Service, U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, U.S. Geological Survey, San Diego Zoo Wildlife Alliance and Tony Ault, Village News Staff Writer.