Hungry New Insectivores in Town

Researcher Frank Santana prepares to release his charges into a mountain stream.

Researcher Frank Santana prepares to release his charges into a mountain stream.

The little dotted frogs could not have picked a more picture-perfect day for their release into a remote mountain stream within their historic habitat. As wind rustles the swaying tree crowns and sunshine warms our backs, the team of multi-agency collaborators—along with a bevy of reporters—descends on Indian Creek in the San Jacinto Mountains. Bred at the San Diego Zoo Institute for Conservation Research, 65 juvenile mountain yellow-legged frogs Rana muscosa are stowed in pairs in Tupperware containers (with puncture holes) in 2 large, temperature-controlled coolers, awaiting their freedom…and a feast of fresh crickets skirting over the water’s surface. It’s an exciting milestone, years in the making.

Amphibian Adventure
In 2002, the U.S. Fish and Wildlife Service listed Southern California’s mountain yellow-legged frog (MYLF) as endangered, with fewer than 200 adult frogs scattered throughout perennial streams in the San Gabriel, San Bernardino, and San Jacinto mountains. In 2006, a group of tadpoles (once referred to as pollywogs) were collected from the wild and brought to the Zoo’s Institute for Conservation Research. Research Coordinator Frank Santana took painstaking care of little guys, monitoring tank temperature, water quality, ambient light, and everything that could possibly impact the froglets’ development.

Though there was high survivorship, breeding seemed to be at an impasse, so Frank came up with an experiment to let a subset of the frogs hibernate for 60 days in a wine chiller. This proved to be the answer to the amphibian amour riddle, as the hibernated individuals were soon mating after “waking,” with six clutches of eggs laid within two days. With the fertility issue solved, Frank was able to shift his focus to field reintroduction efforts, which culminated in the dozen people buzzing about the three release sites in the stream on June 12, 2013. By raising the tadpoles in captivity into their tailless juvenile stage (about 14 months), it is hoped that there will be less predation and higher survivorship of these animals in the wild. Driving up to the release site, Frank confides that these dappled frogs are “just as deserving of a CHP escort as the pandas.” Given the years of research and collaboration required to get to this MYLF release, I’d have to agree.

The radio telemetry "backpack" will enable researchers to keep tabs on the mountain yellow-legged frog for 30 days, when it will be removed.

The radio telemetry “backpack” will enable researchers to keep tabs on the mountain yellow-legged frog for 30 days, when it will be removed.

The Fungus Among Us
Mountain yellow-legged frogs have not graced this stream since the 1990s when the perfect storm of habitat loss and degradation, nonnative introduced trout, which eat the frogs and their eggs, and the deadly amphibian chytrid fungus sweeping the globe, conspired to destroy this species. It’s up to humans to repair MYLF habitat and safeguard against the chytrid fungus. As the road wound higher into the mountains, Frank shared with me the “extra step” taken to ensure these animals released have the best chance at survival. “We are soaking the frogs twice for 4 hours in water containing beneficial bacteria, to protect them against the chytrid fungus.” Dr. Vance T. Vredenburg, a professor at San Francisco State University, discovered that a naturally occurring strain of bacteria may help ward off the fungus in frogs. This could be a game changer for amphibian conservation!

Frank gently released 65 juvenile mountain yellow-legged frogs into the stream.

Frank gently released 65 juvenile mountain yellow-legged frogs into the stream.

Release Me
Frank and Adam Backlin from U.S. Geological Survey (USGS) crouch next to the stream with several Tupperware containers bobbing on the surface. Stream water seeps in through the air holes and the frogs seem giddy with their natural habitat so near. Other USGS staff is testing the tiny “backpacks” of radio transmitters, which will be strapped onto 15 of the frogs released. This will enable researchers to track the frogs for the next 30 days to see where they settle, and then remove the transmitters. Frank wades knee-deep into the creek and gently holds a spotted, two-inch long frog on his palm over the water. The frog pauses (for a photo?), then leaps into the water, diving deep into the blessed muck on the bottom. Frank scoops up another frog. Cameras click. The liberation process is mesmerizing. One frog hops back into his Tupperware, but quickly changes his mind. Splash! As we stand under the warm sun, the frogs begin to swim to the surface, eying their audience from their chilly element. They linger, as we do, savoring this giant leap for amphibian conservation.

THANK YOU! San Diego Zoo Global is grateful to mountain yellow-legged frog recovery collaborators at the Los Angeles Zoo, the U.S. Forest Service, U.S. Geological Survey, California Department of Fish and Game, and U.S. Fish and Wildlife Service.

Karyl Carmignani is a staff writer for San Diego Zoo Global. Read her previous post, Chillin’ Out with Cold-Blooded Creatures.


Facebook Winner Joins Us in the Field

From left to right: Facebook winner Jeff Williams, research technician Frank Santana, UC James Reserve Director Rebecca Fenwick

When we got to the gorgeous University of California James Reserve in the San Jacinto Mountains, the sun was high and the sky was a clear, deep blue. We lucked out. It was the perfect day to take our Facebook winner, Jeff Williams, with us into the field to take part in our mountain yellow-legged frog project. It was also apparent by the conversation we had in the two-hour car ride up to the mountains that Jeff was the perfect candidate to take with us.

An avid outdoorsman, Jeff’s passion for nature and the wildlife therein was palpable. It turned out that Jeff used to breed blue dart frogs, a hobby catalyzed by an encounter he had with wild frogs in Costa Rica. “I thought it was amazing to come across these fluorescent spots of light in the forest all around you,” he said. A love of wildlife also runs in Jeff’s family. After learning that meat came from animals at the age of four, his daughter chose to be vegetarian. “It’s kind of a good thing because it forces us to eat healthier,” Jeff said.

Jeff was also very interested in the project, and asked Frank Santana, our lead field technician, a million questions about mountain yellow-legged frogs (MYLF) and their plight. We learned that the chytrid fungus is the main reason for the frog’s alarmingly rapid decline. The fungus affects the keratin layer of skin and impairs the frogs’ ability to exchange oxygen and carbon dioxide through their skin, resulting in a slow suffocation. The species also faces threats from pollution and introduced predators like brown and rainbow trout. I also learned that historically there were 160 populations of MYLF in the region, now there are just 9. In fact, 33% of all amphibian species worldwide are threatened by extinction, with threats from habitat loss, pollution, introduced species, and chytrid. This knowledge gave our work renewed gravity and purpose in my mind.

When we broke off the beaten path toward the wild stream where we had released about 500 critically endangered mountain yellow-legged frog tadpoles earlier this year, it was clear that we were in for an adventure. Soon we were climbing over fallen logs, thrashing through dense foliage, and wading in knee-deep water. Our goal was to hike upstream in search of tadpoles that may have dispersed from their original release pools. Jeff didn’t get off easy. We put him to work searching for tadpoles and measuring the length, width, and depth of certain pools, and he gladly indulged us. He was an important part of the team for a day. He even brought some useful equipment with him, like a super-small, super-bright LED flashlight that really came in handy for searching dark pockets of water. In fact, many of the pictures we captured of tadpoles wouldn’t have come out without Jeff shining his flashlight in the water.

After a few hours of searching the stream we had yet to find tadpoles, even with the help of UC James Reserve Director Rebecca Fenwick. It wasn’t until we got to the most upstream release pool that we saw about five tadpoles, which believe it or not is a good sign, since tadpoles face threats from many predators in the wild. It was an incredible feeling to finally spot the little guys. “After all that work it’s good to see that they’re still there and hopefully they’ll start to see some success,” Jeff said. I think we can all agree.

It was an absolute pleasure having Jeff along with us. We appreciated his help and had an awesome time “doing science” with him. Like our facebook page for a chance to fill Jeff’s shoes and ride along with us into the field for our cactus wren project.

Matt Steele is the social media planner for San Diego Zoo Global. Read his previous post, Summer SCVNGR Safari.


Mountain Yellow-Legged Frogs: Life Beyond the City

The San Gabriel Mountains tower over the Los Angeles basin like sentinels. Heading up a winding highway into the mountain wilderness leaves all signs of the urban landscape behind. Stoplights, mini malls, and highways are replaced with trees, birds, and steep cliffs. Climbing further up the mountain reveals a wilderness teeming with amazing sights and a cacophony of sounds that stimulate the senses. Colorful butterflies, amazing wildflowers, and chirping frogs are all regular parts of the mountain landscape.

As a biologist with the San Diego Zoo Institute for Conservation Research, Southern California’s mountains are my office and outdoor laboratory. The goal of my research is to improve our understanding of the critically endangered mountain yellow-legged frog Rana muscosa with the ultimate goal of reintroducing poopulations back into the mountains of Southern California. Every summer for the last three years I have headed up into the mountains to learn as much as possible about these magnificent and beautiful frogs. One third of the world’s amphibians are in decline, and by focusing our research on the mountain yellow-legged frog, the San Diego Zoo is working to do our part to save frogs from extinction.

Scientists noticed that mountain yellow-legged frogs were experiencing severe declines in Southern California during the 1990s, and in 2001 they were listed as an endangered species under the Federal Endangered Species Act. The exact reason for the drastic declines are unclear, but we suspect that the deadly amphibian chytrid fungus may have played a major role in population declines. In addition, the species faces pressures from habitat loss, wildfires, water pollution, global warming, and introduced predators. Today only nine populations of mountain yellow-legged frogs exist in Southern California.

This summer I am focused on understanding the population demographics of wild mountain yellow-legged frog tadpoles. With the assistance of our summer research fellow Stephanie Wakeling, we are hoping to gain insight into the survival rates of tadpoles during their two to three years of life before they metamorphose into frogs. Keep an eye out for a regular series of blog entries as we share this exciting research with you throughout the summer.

Frank Santana is a research technician at the San Diego Zoo Institute for Conservation Research. Read his previous post, Desert Memories.