Pacific Southwest RegionCalifornia, Nevada and Klamath Basin
‘All is not lost’
The Woolsey Fire burned nearly 100,000 acres, destroying more than 1,500 homes, businesses, and other structures from inland Thousand Oaks to the seaside town of Malibu between November 8 through November 16, 2018. When it was safe for residents to return home, a team of scientists struck out to visit sites where California red-legged frogs were reintroduced in recent years in the hope that the struggling population of frogs had survived. Credit: Ashley McConnell/USFWS
Rare California red-legged frogs fight for survival following SoCal wildfire
By Ashley McConnell
December 14, 2018
Amid an ashy creek bed in the Simi Hills, rare frogs are fighting for survival following the Woolsey Fire, which swept across Ventura and Los Angeles Counties this November, prompting mass evacuations. While thousands of residents fled their homes, California red-legged frogs, a threatened species, hunkered down in creek bottoms, and waited.
Fueled by persistent Santa Ana winds, the Woolsey Fire burned nearly 100,000 acres, destroying more than 1,500 homes, businesses, and other structures from inland Thousand Oaks to the seaside town of Malibu. Nearly half of the Santa Monica Mountains burned, including sites where California red-legged frogs were reintroduced in recent years to help boost the dwindling population.
The Woolsey fire ignited on November 8, 2018 and burned nearly 10,000 acres of land. The fire destroyed 1,643 structures, killed three people, and prompted the evacuation of more than 295,000 residents. It was one of several fires in California that ignited on the same day. Both the Woolsey Fire and nearby Hill Fire were contained on November 16. Credit: Peter Buschmann/USFS
When it was safe for residents to return home in the days following the fire, a team of scientists huddled around a creek bed surrounded by darkened hillsides. Emergency response helicopters flew overhead.
Chris Dellith, senior wildlife biologist with the U.S. Fish and Wildlife Service surveys the charred landscape in search of California red-legged frogs following the Woolsey Fire that swept through Los Angeles and Ventura Counties in November 2018. Credit: Hazel Rodriguez/USFWS
“There’s one there. It’s alive,” said Chris Dellith, senior wildlife biologist with the U.S. Fish and Wildlife Service. An adult California red-legged frog hopped from a tumbled tree branch into the water and disappeared.
Dellith and partners from federal and state agencies came together to assess damage areas where the threatened species is known to exist, including a site in the Simi Hills where for the past four years, scientists have collected frog eggs to transplant to new areas in the Santa Monica Mountains to aid in the recovery of the species. All four sites were impacted by the fire.
While driving southbound on Highway 101 en route to the survey site, Dellith looks at the charred landscape and reminisces about a childhood spent playing in those very hills. “These are my old stomping grounds.” When asked how many fires he’s been through since he moved to California in 1971, he said, “I’ve lost count.”
We rolled down the windows as we entered the town of Calabasas; the air is thick with the smell of a summer campfire.
Fueled by persistent Santa Ana winds, the Woolsey Fire burned nearly 100,000 acres. Nearly half of the Santa Monica Mountains burned, including sites where California red-legged frogs were reintroduced in recent years to help boost the dwindling population. Credit: Hazel Rodriguez/USFWS
It will be at least a year until scientists are able to determine the fire’s effects to the California red-legged frog population in the Simi Hills, and now, a new challenge for the rare amphibians - winter rains.
“The rains are a mixed blessing,” Dellith said. An hour-long deluge could send earth loosened by the fire into the stream bed, bringing with it toxic ash that could kill the frogs and leave their breeding habitat without clean water to mate and lay their eggs during the spring breeding season.
A consistent drizzle over a day, on the other hand, could have the opposite effect, providing just enough water to germinate the unburned seedbank, which in turn would grow roots and anchor the soil on the adjacent slopes in place.
Tim Hovey, senior environmental scientist with California Department of Fish and Wildlife, has monitored California red-legged frog populations in the area for the last 15 years.
“It’s terrible that this happened, but I’m encouraged by what I see,” Hovey said as he looked up at the blackened hillsides scattered with oak trees. “The sloping hillsides around this creek bed are not very steep, so we may not see a tremendous amount of sediment flowing down. We’ll see what happens after the rains.”
Hovey and the other scientists have a strategy to intervene following winter rains if needed.
Tim Hovey, senior environmental scientist with California Department of Fish and Wildlife, observes a California red-legged frog in an ashy creek bed near Calabasas following the Woolsey Fire. Hovey has monitored California red-legged frog populations in the area for the last 15 years. Credit: Hazel Rodriguez/USFWS
Following the Copper Fire in 2002 which impacted portions of the San Francisquito Canyon in Los Angeles County, “we created artificial pools alongside the existing stream channel that had been closed in by the sediment from heavy rains,” said Elizabeth Gallegos, biologist with the U.S. Geological Survey. “The frogs successfully bred in those pools until the habitat reestablished itself.”
Years later, Gallegos said, “the frogs in that area are doing great.”
The frogs in the Simi Hills have also been doing well in recent years, Gallegos said. She and others have been surveying the frog population there since 2009. In 2017, she documented 76 egg masses in just a 250 meter reach of the creek bed.
There were enough frogs in the Simi Hills to support a reintroduction program that began in 2014, when scientists moved the first egg masses from the Simi Hills into a site in the Santa Monica Mountains National Recreation Area.
Elizabeth Gallegos, biologist with the U.S. Geological Survey, kneels beside a creek bed near Calabasas, scanning the water for signs of life following the Woolsey Fire in November 2018. Credit: Hazel Rodriguez/USFWS
Since then, egg masses from the Simi Hills have been transplanted year after year, in the hopes that eggs would metamorphose into tadpoles and ultimately adult frogs that would then reproduce on their own. In 2017 and 2018, scientists rejoiced when frogs were documented reproducing at two of the introduction sites – a sign of the program’s remarkable success.
In 2016, California red-legged frog eggs were collected from an existing area in the Simi Hills and were transported to new areas in the Santa Monica Mountains, with the goal of creating a new population of reproducing adult frogs. Credit: National Park Service
“We’re concerned about the introduction sites, but we’re certainly not going to give up,” said Seth Riley, wildlife ecologist with the Santa Monica Mountains NRA.
Riley and the rest of the team plan to keep a close eye on the frogs in the Simi Hills and survey the introduction sites in the coming weeks. They’ll conduct nighttime surveys before and after winter rains to assess habitat impacts and collect data.
While the future of the reintroduction program remains uncertain following the fire, Riley said that the team “would not put frogs into unsuitable habitat.”
“It will take a while for the habitat to recover, but it will recover,” Hovey said. “Even now, we see little sprouts of green coming up. The vegetation will return.”
While wildfires remain a threat to the long-term sustainability of the California-red legged frog population in California, Hovey, Dellith and others remain optimistic.
“There’s still hope for this species. All is not lost,” Dellith said. “It’s just going to take time.”
While California red-legged frogs range from extreme northern portions of Baja California, Mexico to northern California, they exist in only a few watersheds in Southern California. They have been lost from 70 percent of their historical range due to habitat loss and competition for resources with non-native species, like the bullfrog.
The California red-legged frog was listed as threatened under the Endangered Species Act in 1996. Since listing, the U.S. Fish and Wildlife Service has worked alongside the U.S. Geological Survey, National Park Service, California Department of Fish and Wildlife, California State Parks, Santa Monica Mountains Conservancy, Mountains Recreation and Conservation Authority, and others to support the species’ recovery.
About the writer...
Ashley McConnell is the public affairs supervisor for the Ventura Fish and Wildlife Office. Ashley established her love of wildlife and the great outdoors as a child exploring national parks in South Africa. Today, she guides a team of communicators who tell stories about the unique and diverse wildlife and wild places of the southern and central California coast.
Other stories by Ashley:
- Salinas Children Restoring Monterey's Coastal Dunes
- The Refugio Oil Spill, One Year Later Biologists Reflect on Their Experiences
- Orphaned Western Snowy Plover Chicks Return to the Wild at Coal Oil Point Reserve in Santa Barbara
- USFWS Biologist Inspires "Sense of Wonder" in Southern California's Urban Children
- Monarch Butterflies of Ellwood Mesa