Los Angeles Times
Hopping to it to preserve the rare mountain yellow-legged frog
Researchers' efforts to breed more of the California amphibians
include refrigerating them to mimic their winter hibernation.
March 06, 2010|By Louis Sahagun
Some like it hot. Apparently, the endangered mountain yellow-legged frog is not among them. The 3-inch-long amphibians much prefer it cold as melting snow. So conservationists at the San Diego Zoo have placed two dozen of the nearly extinct frogs in refrigerators they joshingly refer to as "Valentine's Day retreats" in hopes the amphibians will emerge with the urge. To mate, that is. The big chill at the zoo's Institute for Conservation Research represents one of the nation's most ambitious wildlife reintroduction experiments. If it is successful, the frogs could produce upward of 6,000 tadpoles next month -- all of them scheduled for a spring homecoming in a remote San Jacinto Mountains stream from which they have been absent for a decade. Scientists hope many of those tadpoles will mature and produce new generations in the wild, paving the way for the Rana muscosa population to reestablish residency in Southern California and grow exponentially. "Will it work? We think so," said Jeffrey Lemm, a zoo research coordinator. "A month from now, there could be tubs of tadpoles all over the place. Eventually, we may have thousands of adult frogs in self-sustaining populations for the first time in half a century."
Mountain yellow-legged frogs thrived for thousands of years in hundreds of streams cascading down the San Bernardino, San Gabriel and San Jacinto mountains. Since the 1960s, the species has been decimated by an array of threats: fires, mudslides, pesticides, fungal infections, loss of habitat as a result of development, and the appetites of nonnative trout, bullfrogs and crayfish. Today, fewer than 200 of their descendants are believed to exist in nine isolated wild populations, including a group in the San Gabriel Mountains' Devils Canyon that survived last year's devastating Station fire. Their minuscule, scattered population gives mountain yellow-legged frogs the distinction of being one of the most endangered amphibians on the planet. The most intimate details of their mating behavior are the focus of a master's thesis project being conducted at the institute by research technician Frank Santana.
In their native habitat, the frogs flock to streams gushing with spring snowmelt. Males announce their availability for amphibian amour with a low-pitched underwater bark. Parental discretion is advised for what follows: "A male gets a good grip of a female with his forearms, and the female, if she's in the mood, let's him," Santana said. "Then the male thrusts his whole body to stimulate the release of her eggs. The female goes into contractions as both arch their backs to line up their cloacae." Sperm and eggs are released simultaneously. Tadpoles emerge from the eggs about three weeks later. In the wild, only 3% to 5% mature into adult frogs. "In the laboratory, the hard work comes when we've got a bazillion 2-millimeter-long tadpoles on our hands in need of daily water changes, and meals of frozen lettuce and fish food," Santana said.
The zoo's recovery program was launched in the summer of 2006, with 82 tadpoles rescued from a drying creek in the San Bernardino National Forest. Two years later, institute researchers discovered a clutch of 200 eggs in one of their tanks. However, the frogs were younger than is typical for breeding and only a handful of the eggs were fertile. The institute became the first to breed a yellow-legged frog in captivity when one of those eggs produced a tadpole that matured into a still-surviving adult. Now the institute has 61 frogs, including the 16 females in the refrigerator -- each one of them, Lemm said, "looking nice and healthy and bulging with 200 to 300 eggs." All the tadpoles produced in the laboratory will be reintroduced into a mountain stream that U.S. Geological Survey biologists have determined is free of predators.
The recovery effort has been funded by the California Department of Transportation to mitigate for emergency work to stabilize a slope near the frog's habitat on California 330 in the San Bernardino Mountains. It is part of an ongoing collaborative effort of government and nonprofit partners to increase the number of frogs in native habitat and in captive breeding programs. The Fresno Chaffee Zoo recently received about 100 tadpoles rescued last summer from the Station fire area. The Los Angeles Zoo and the Living Desert in Palm Desert will each get 10 adult frogs for captive breeding purposes.
In the meantime, federal wildlife authorities are developing measures to reduce the effect of human activities in areas where the yellow-legged frog is still found and may be reintroduced. That includes a remote stretch of Tahquitz Creek in the San Jacinto Wilderness near Idyllwild, where two yellow-legged frogs were discovered last year. "A few years ago, there wasn't even a captive breeding program for these frogs," Santana said. "Now, we are hoping to reestablish populations by mimicking their natural cycles. For these frogs, that means winter hibernation, spring thaw and lots of tadpoles. Hopefully."
louis.sahagun @latimes.com
http://articles.latimes.com/2010/mar/06/local/la-me-frogs6-2010mar06
Copyright 2010 Los Angeles Times
The Press-Enterprise
Scientists release endangered frogs near Idyllwild
11:07 PM PDT on Thursday, April 15, 2010
By JANET ZIMMERMAN
In an icy mountain stream near Idyllwild on Thursday, scientists planted about 500 eggs of the endangered mountain yellow-legged frog as part of an unprecedented program they hope will save the species from extinction. Less than 200 of the frogs live in Southern California streams where they were once prolific, said Jeff Lemm, research coordinator for the San Diego Zoo's Institute for Conservation Research in Escondido. Thursday's release involved just half of the eggs laid so far this spring by pairs of frogs housed for captive breeding in 250-gallon tanks at the institute. Wildlife biologists plan to release the remainder as tadpoles this summer. "If all these eggs survive, we'll be tripling the population in the wild," Lemm said as the eggs were placed in a bucket on ice and driven more than two hours to Indian Creek, a tributary of the San Jacinto River.
CHILLED FROGS
Lemm's efforts go back to 2006, when 82 tadpoles were rescued from a dry creek bed not far from the release. Of those, 63 survived and they produced one offspring. Troubled by the limited breeding, Lemm and his colleagues decided to replicate the frogs' hibernation in chilly water before they mate in spring. They tucked half the frogs into clear plastic shoe boxes and stored them in wine refrigerators at 40 degrees for three months. The rest remained in their 55-degree tanks. While the warm-water frogs were less amorous, the "chilled" frogs immediately went to work 10 days ago. They produced more potential tadpoles than the institute could possibly house. So rather than waiting for summer, scientists with the U.S. Geological Survey urged an early release. They had staked out the perfect habitat at a private reserve owned by UC Riverside, which offers the deep, bedrock pools and undercut banks the frogs prefer.
EGG RELEASE
Waist-deep in the stream, federal scientists Adam Backlin and Liz Gallegos carefully lifted the gelatinous clumps of eggs -- black spots encased in clear sacs -- from a plastic tub. They slid them into submerged cages made of wire mesh and plastic pipe to shield the eggs from raccoons and other predators. By the time the tadpoles emerge in about two weeks, they will be able to swim free of the cages. They most likely will be tracked by underwater cameras with live video streaming 24 hours a day. "Definitely a portion of them won't survive. We're hoping it will be a low number," Backlin said. The disappearance of the frog is part of an overall decline of amphibian populations worldwide. A third fall victim to the chytrid fungus, the rest to predatory fish, pollution and habitat loss, he said. "That's why we feel it's now or never for this species," one of the most endangered amphibians in the world, Backlin said. The success, or failure, of the captive breeding program ultimately could affect humans. Frogs are considered indicators of environmental health; when they aren't thriving, something could be wrong with the streams that provide drinking water for humans, Lemm said.
Reach Janet Zimmerman at 951-368-9586 or jzimmerman@PE.com
http://www.pe.com/localnews/stories/PE_News_Local_W_frog16.44c8beb.html
Rare frog could earn state protection
10:00 PM PDT on Tuesday, June 29, 2010
The state will consider an environmental group's request to give endangered status protection to two species of the mountain yellow-legged frog, one that lives in the mountains of Southern California and the other in the Sierra Nevada. The California Fish and Game Commission will vote at its Aug. 5 meeting whether to accept a listing petition by the Center for Biological Diversity and start a year-long review on the status of both species. The frogs once were abundant in the state's mountains, but populations have dwindled because of predatory trout, pesticides, fungus and recreational activities, among other threats. The southern species is the focus of a San Diego Zoo breeding program that is reintroducing the frogs' eggs in a stream near Idyllwild; tadpoles that recently hatched at the zoo's lab will be planted there next month. The remaining adult population in the wild is estimated at 200 frogs. The southern mountain yellow-legged frog already is listed under the federal Endangered Species Act; a state designation could increase funding for stream restorations, give the frog higher priority for conservation actions and protect habitat where it was once found, said Jeff Miller, a conservation advocate for the center. The Sierra population is a candidate for listing under the federal Endangered Species Act.
--Janet Zimmerman jzimmerman@PE.com
ESCONDIDO: Endangered frogs get second chance
IDYLLWILD CREEK COULD HOLD KEY TO ENDANGERED SPECIES' SURVIVAL
By DEBORAH SULLIVAN BRENNAN - dbrennan@nctimes.com
Posted: Friday, May 7, 2010 9:14 pm
A pair of mountain yellow-legged frogs, which were captured in the wild, sit in a terrarium at the San Diego Zoo's Institute for Conservation, adjacent to the Wild Animal Park in July. (Photo by Hayne Palmour IV - Staff photographer)
An undulating mass of frog eggs in a San Jacinto Mountain stream contains what could be the next generation of a nearly extinct species, along with clues to a worldwide decline in amphibians. The mountain yellow-legged frog eggs had been incubating at the San Diego Zoo's Institute for Conservation Research near Escondido, where researchers had painstakingly bred some of the last remaining adult frogs known to exist.
Last month, they placed the eggs in a cold mountain creek near Idyllwild, 76 miles north of Escondido. With fewer than 300 adult mountain yellow-legged frogs in Southern California, state biologists have described the creature as the most endangered amphibian in the state and one of the most endangered in the country. Its plight is even more urgent in light of the global collapse of amphibian populations, they say. "One-third of the world's amphibians are in danger of extinction right now," said Jeff Lemm, research coordinator for the institute. "That's right on par with dinosaur extinctions. It's all happening at once." Mountain yellow-legged frogs were once common throughout high-elevation streams in Southern California, but by the turn of the century they had nearly vanished. In 2002, the species was listed as endangered with the U.S. Fish and Wildlife Service, meaning it's unlikely to survive without human intervention. In 2006, scientists with the U.S. Geological Survey rescued about 80 tadpoles from a dry creek bed in the San Jacinto Mountains, said Adam Backlin, an ecologist with the agency. They placed them at the zoo's research facility, where they were raised in tanks until they were ready to breed this year.
Breeding program
Yellow-legged frogs are a relatively long-lived species that can survive 10 to 15 years, but require two years to metamorphose from tadpoles to frogs and another two years to reproduce, Backlin said. Their long maturation period leaves them vulnerable to predators in the wild, and makes them tricky to breed in the lab. In addition, the high-altitude frogs need cold, pristine water and constant care from their handlers, Lemm said. "It's a lot of work to keep their water clean," he said. "When you get tadpoles, it's three times as much work." Researchers tried breeding the amphibians last year, but produced only one adult frog. This year, they tried simulating natural winter conditions by putting the frogs in tubs of mud placed in beverage coolers chilled to 40 degrees, Lemm said.
They wound up with more than 1,200 eggs. About half of those eggs remain in the lab, to be released as tadpoles. The others are now incubating in underwater cages in a creek running through the James Reserve in Idyllwild, a research area in the University of California's Natural Reserve System. There, reserve staffers observe them through an improvised monitoring system of video cameras designed to inspect boat hulls, and point-and-shoot underwater cameras purchased online for $100 each. Last week, the pale egg masses bobbed in the stream's currents, captured in real time on camera. Scores of black frog embryos were visible amid the transparent eggs. James Reserve director Becca Fenwick and other researchers scrutinize them daily for glimpses of developing tails and other signs they are ready to hatch. When the tadpoles emerge, they'll feed on what remains of their eggs, then swim through the mesh cage, seeking leaf litter for cover. The hope is that the tadpoles will congregate in a sheltered spot where researchers can place another webcam to watch their development, Fenwick said. As more tadpoles hatch in the lab, scientists will reintroduce them to the creek in batches, marking them with fluorescent dots under their skin to record their release dates. They'll measure survival rates of the different groups and schedule future reintroductions accordingly, studying elements of their environment that help or hinder recovery.
Threats to survival
Scientists have scrambled over the last decade to figure out why frog populations are dying out. One major factor in the decline of mountain yellow-legged frogs may have been predators such as the non-native trout stocked in mountain streams. Tim Hovey, a fisheries biologist with the California Department of Fish and Game, said the department has revisited its longtime policy of stocking those streams and instead is removing trout from areas containing frog habitat. Other possible reasons behind the frogs' disappearance include subtle changes in water chemistry and temperature, fungal infections and water contamination ---- hazards that may also affect human health.
The chytrid fungus is a disease infecting frogs worldwide that scientists believe damages the creatures' ability to breathe through their skin. Frogs are acutely sensitive to water quality, and serve as an indicator species, foreshadowing contamination that may eventually affect humans. Studies by UC Berkeley professor Tyrone Hayes showed that frogs suffer hormonal damage from the common pesticide atrazine at levels far below the legal limit, and that the chemical is linked to cancer and fertility problems in humans. Climate change and increased ultraviolet radiation ---- possible threats to humans ---- may be harming frogs as well. "For the last 10 to 15 years, globally, amphibians have been declining dramatically," Backlin said. "So there's a real interest in why that is occurring. So by putting them back in the environment, we can examine why that is happening. This is a way of determining if this will eventually affect us." Biologists also fear that the loss of frogs may have widespread consequences on their ecosystems, but warn that we might not identify those effects before it's too late. "We see every species as a playing card," Hovey said. "We have this house of cards. If you keep taking cards out, eventually it will collapse. They provide an intricate biological function, and we as a species have absolutely no idea what it is." Lemm said that restoring the frogs to San Jacinto Mountain streams is part of an increased effort to preserve local as well as exotic species at the institute. "This is a really big eye-opener for people of Southern California," Lemm said. "Pandas and tigers and rhinos are very important, but in our own backyard we have critically endangered species that are disappearing left and right. So this is an important step toward promoting the need for conservation here."
Call staff writer Deborah Sullivan Brennan at 760-740-5420
Copyright 2010
North County Times - Californian.
A pair of mountain yellow-legged frogs, which were captured in the wild, sit in a terrarium at the San Diego Zoo's Institute for Conservation, adjacent to the Wild Animal Park in July. (Photo by Hayne Palmour IV - Staff photographer)
Adam Backlin and Liz Gallegos of the U.S. Geological Survey lower a cage of mountain yellow-legged frog eggs into a San Jacinto Mountain stream last month. Scientists are trying to bring the frog back from the brink of extinction. (Photos courtesy Becca Fenwick)
U.S. Geological Survey ecologist Adam Backlin places mountain yellow-legged frog eggs in a protective cage in a San Jacinto Mountain stream last month. The frog was listed as endangered with the U.S. Fish and Wildlife Service in 2002, meaning it's unlikely to survive without human intervention. (Photos courtesy Becca Fenwick)
Adam Backlin and Liz Gallegos of the U.S. Geological Survey place mountain yellow-legged frog eggs in a San Jacinto Mountain stream last month. Scientists say the frog is the most endangered amphibian in the state. (Photos courtesy Becca Fenwick)
http://www.nctimes.com/news/local/escondido/article_b9e5927a-0933-5f05-a768-f5f15b84be5c.html
The Desert Sun
Endangered frog tadpoles released into stream near Idyllwild
DESERT SUN AUGUST 24, 2010
Three dozen tadpoles from an endangered species of frog bred at the San Diego Zoo were released into a stream near Idyllwild today. The tadpoles were released into the stream, within the University of California James San Jacinto Mountains Reserve, with the hope of restoring the Southern California population of the mountain yellow-legged frog. ``This is a very exciting day for everyone involved in this important effort to save this frog,'' said Becca Fenwick, director of the Riverside County reserve. ``We are proud to be part of the effort to save this species that once thrived throughout Southern California.''
Researchers and scientists will regularly monitor the progress of the tadpoles. ``We will be monitoring carefully in hopes these tadpoles will be the beginning of the species' resurgence,'' Fenwick said. Earlier this year, eggs from the yellow-legged were reintroduced in the same area. The project to save the species of amphibian is a collaboration between the San Diego Zoo's Institute for Conservation Research, U.S. Geological Survey, U.S. Forest Service, U.S. Fish and Wildlife Service, and California's Fish and Game and Transportation departments. The mountain yellow-legged frog is one of three frogs or toads on the federal Endangered Species List in Southern California.
Today, only a small population of less than 200 adult mountain yellow-legged frogs can be found in the San Gabriel, San Bernardino and San Jacinto mountains.
Endangered tadpoles released into SoCal stream
The Associated Press
Posted: 08/24/2010 05:27:06
PM PDT
IDYLLWILD, Calif. Researchers have released dozens of tadpoles into a Riverside County stream in hopes of reviving a frog species endangered in the region. San Diego Zoo officials say zoo researchers bred the 36 mountain yellow-legged frog tadpoles that were released Tuesday into a stream near the town of Idyllwild. The mountain yellow-legged frog is on the federal Endangered Species List in Southern California and has recently been proposed for listing under the California Endangered Species Act. Fewer than 200 adult mountain yellow-legged frogs are thought to remain in the region's mountain ranges. Researchers had released some 500 mountain yellow-legged frog eggs into the creek in April, but the tadpoles from those eggs remain too small for scientists to determine how many survived.
http://www.mercurynews.com/breaking-news/ci_15882476?nclick_check=1
Tadpoles bred in San Diego Zoo released
Aug 24,
2010 By City News Service
Yellow-legged frog tadpoles were released into a stream in Idyllwild Tuesday.
Photo
courtesy J.P. Crumrine/Idyllwild Town Crier
Three dozen tadpoles from an endangered species of frog bred at the San Diego Zoo were released into a stream near Idyllwild on Tuesday, zoo officials said. The tadpoles were released into the stream, within the University of California James San Jacinto Mountains Reserve in Riverside County, with the hope of restoring the Southern California population of the mountain yellow-legged frog. "This is a very exciting day for everyone involved in this important effort to save this frog," said Becca Fenwick, director of the reserve. "We are proud to be part of the effort to save this species that once thrived throughout Southern California." Researchers and scientists will regularly monitor the progress of the tadpoles. "We will be monitoring carefully in hopes these tadpoles will be the beginning of the species' resurgence," Fenwick said. Earlier this year, eggs from the yellow-legged from were reintroduced in the same area.
The project to save the species of amphibian is a collaboration between the San Diego Zoo's Institute for Conservation Research, U.S. Geological Survey, U.S. Forest Service, U.S. Fish and Wildlife Service, and California's Fish and Game and Transportation departments. The mountain yellow-legged frog is one of three frogs or toads on the federal Endangered Species List in Southern California. Tuesday, only a small population of less than 200 adult mountain yellow-legged frogs can be found in the San Gabriel, San Bernardino and San Jacinto mountains.
Yellow-legged frog tadpoles were released into a stream in Idyllwild Tuesday.
http://www.delmartimes.net/news/273502-tadpoles-bred-in-san-diego-zoo-released
The San Diego Union-Tribune, LLC
Endangered frogs find new life
By Mike Lee
Originally published August 24, 2010 at 2:39 p.m., updated August 24, 2010
at 6:08 p.m.
Ken Bohn / San Diego Zoo
Jeff Lemm, a specialist at the San Diego Zoo Institute for Conservation Research, examines tadpoles in a bag before they are transported to a wild stream near Idyllwild.
IDYLLWILD, Calif. A four-year campaign to keep mountain yellow-legged frogs from disappearing forever took a big jump forward Tuesday, when a team of researchers released 36 tadpoles into a crystalline stream in the San Jacinto Mountains.
After a painstaking review of possible release sites, scientists selected two shallow, rock-protected pools inside a University of California natural reserve at about 6,000 feet above sea level. They hauled 5-gallon containers of 1- to 2-inch long tadpoles through the forest to partly submerged pens designed to protect the young frogs from predators in the short-term. "I think that they will do fine now that they are here," said Jeff Lemm, an amphibian specialist at the San Diego Zoo Institute for Conservation Research. "The worst part is the transfer."
The project was the first known attempt to reintroduce yellow-legged tadpoles into the wild and it follows a similar effort with eggs of the same species four months ago. Fewer than 200 adults live in the mountains of Southern California, where they once thrived.
Drought, disease, predators, pesticides and development have threatened frog populations around the world, spurring international concern and conservation efforts. The mountain yellow-legged frog is one of three frogs or toads in Southern California on the federal Endangered Species Act list. That's why U.S. Forest Service biologist Anne Poopatanapong quickly called colleagues who were concerned about the species when she saw tadpoles in a parched stream bed in 2006. "I just went out in the evening and the creek was dry," she said. "They looked a little precarious."
The next day, biologists rounded up about 80 tadpoles and took them to aquarium tanks at the zoo's conservation center on the east edge of Escondido. Ever since, Lemm has been caring for the creatures and encouraging them to breed by putting them in chillers to simulate natural hibernation conditions. Historically, frogs have proved hard to breed in artificial conditions, but Lemm beat the odds and became the first to pull off the trick.
That allowed him and a multi-agency team to plan Tuesday's tadpole project near where the tadpoles' parents were initially found. Frank Santana, a graduate student at San Diego State University, surveyed several stream stretches in the region to find the best reintroduction sites. "We have done some statistical methods to figure out what are the habitat requirements of the frog," he said. "We are definitely learning a lot."
Four groups of tadpoles were freed under slightly different conditions and marked with color-coded plastic tags about the size of pin heads. The colors should allow biologists to figure out which groups fare best and what conditions are optimal for larger releases of tadpoles. It will take years to figure out if the project is successful, with the goal ultimately to restore thousands of tadpoles to their native habitat, said Adam Backlin, an ecologist for the U.S. Geological Survey. "We are going to be looking for (the tadpoles) and trying to keep track of them, but we are really not going to know until they turn into frogs," he said. "That would be the ultimate success sometime down the road to come here and see egg masses that were laid by these frogs. But it's going to be a waiting game." Despite the potential for setbacks including a lack of rain Poopatanapong is energized by the early successes of the program. "We are making these huge leaps of getting them back into the wild in such a short time," Poopatanapong said. "With other endangered species, it takes years and years or decades to try and get them reintroduced."
Mike Lee: (619) 293-2034; mike.lee@uniontrib.com; follow on Twitter @sdenvirobeat.
Jeff Lemm, a specialist at the San Diego Zoo Institute for Conservation Research, examines tadpoles in a bag before they are transported to a wild stream near Idyllwild.
http://www.signonsandiego.com/news/2010/aug/24/endangered-frogs-find-new-life-in-mountain-stream/