Photo by Hunter Harding
Written by Hunter Harding
The California red-legged frog, the state amphibian, has declined sharply due to human activity, despite its long-standing cultural significance dating back to an 1865 Mark Twain story, “The Celebrated Jumping Frog of Calaveras County.” The CI Conservation Center, in partnership with the Santa Barbara Zoo, is working to ensure that these frogs keep their place in the California ecosystems.
The Conservation Story
As reported by the Center for Biological Diversity, the California red-legged frog was once common throughout the state’s waterways but now occurs in only about 30% of its historic range, representing about a 90% population decline. Nadya Seal, a conservation science associate with the Santa Barbara Zoo, explained in an interview that various factors have led to the decline of the population in the Santa Monica Mountains.
The California red-legged frog’s conservation story begins with the Gold Rush. “They were actually eaten by gold miners,” Seal said. “They thought frog legs were delicious, so they brought in bullfrogs to supplement the supply.”Native to the eastern United States, the bullfrog became an invasive species in California, disrupting the red-legged frogs’ ecosystems.
Due to their use as food and replacement by bullfrogs, the historical local populations of these frogs were made locally extinct by 1970. However, one population remained and was unable to reach its historic habitat due to expanding infrastructure and the creation of the 101 freeway. Now federally listed as a threatened species, the CI Conservation Center has taken in its first batch of eggs this year to restore populations of this iconic frog.
Seal mentioned another issue impacting these frogs today. “Amphibians worldwide are affected by a fungus called chytrid,” Seal said. Chytrid causes the infected amphibian to develop a skin disease called chytridiomycosis that eventually leads to death. “There are different strains of chytrid and there are local strains that amphibians have adapted to, but there’s also really global, kind of nasty strains that can wipe out populations.” While the California red-legged frog is more likely to adapt to different strains, chytrid is still a big issue because of its ability to travel. Seal explained that people play a big role in how the fungus spreads. “People that will hike in one area, drive and then hike in another area without cleaning their boots in between can bring chytrid.” Because humans can travel much faster and farther than other animals that may transport the fungus, the sudden introduction leaves little time for species to adapt. “We spread things because we have engineered ways to travel quickly,” Seal stated.
Why Do These Frogs Matter?
All of the Earth’s species have particular and important roles they play in their ecosystems, but frogs in general carry a significant amount of responsibility. Seal explained that frogs are a critical aspect of agriculture. With a diet made up of mostly insects, “they eat a lot of pests that affect crops and so they can actually have a pretty decent impact on the agricultural success of the area.”
Frogs are also indicator species. “Amphibians are very sensitive to changes in their environment.” The traits that enable them to live in water and on land simultaneously make them highly sensitive to change, providing early signs of disruption in their ecosystems. “The amphibian population is going to be the first one that you’ll notice those changes happening and the importance of that is that it’s a lot easier to act earlier on than it is when it’s potentially too late.”
Without species like the California red-legged frog, conservation could look very different. “If we don’t have the kind of indicator species telling us early on when there’s a problem, then you could potentially have ecosystems that are beyond our capacity to repair.” Seal goes on to stress that “we’re talking about water sources and water sources are essential to everything.”
The Conservation Project
In 2014 the National Park Service asked the zoo to help with the translocation of the species to build resilience and grow populations. By taking half of the eggs from 10% of the egg masses they found and moving them into designated pens, the park service monitored and supported the growth of a new generation of California red-legged frogs.
After the partnership began and success rates increased, the Woolsey fire in 2019 burned through all but one of the sites. The following storms worsened conditions. Seal recalled, “In an emergency, before the storms, we took in some of the egg masses and we reared them at the zoo and those ended up being the only tadpoles that survived from the translocation.” The team took in more masses before 2023’s severe storms, prompting the park service to request that the zoo continue rearing the frogs.
Seal explained that while there are many benefits to rearing animals in their natural habitats, there are also many risks. The significance of these risks led the team to decide that bringing the tadpoles into a conservation setting would be the most beneficial until stronger populations are established. “Let’s take the opportunity to pull some of those egg masses and headstart them at the zoo and let’s just be a little more proactive about this,” Seal stated about the decision.
In April of 2023 CI announced its partnership with the zoo, providing the necessary room to expand conservation efforts. Now located on the western edge of campus in Modoc Hall, the conservation center is proud to boast the California red-legged frog as their first conservation animal in the building.
Seal reflected on her role in conservation, stating, “On a personal note, I have three kids and I grew up fascinated with nature and wildlife and, you know it’s a little cliché to say. But I want that same thing, the same opportunities, to be there for them.” She continued, “I want to keep the world as intact as I can.”
Intersection of Music and Conservation
Nicolas Burdick, a musician and seventh year biology and psychology student, is aiding in the conservation of the California red-legged frogs through bioacoustics.
Burdick began his higher education journey as a music major at Santa Barbara City College, focusing on sound engineering for film. As the pandemic decreased his ability to go to music studios, he began to dive into the world of audio on his own while studying psychology. Burdick soon took an interest in neuroscience and animal behavior, leading him to take a few biology courses, where he became hooked on bioacoustics.
“I found out that Dr. Alvarado had been doing a bat project where they were listening for bats on the Channel Islands and I just really wanted to go,” Burdick stated in an interview. “I was still a psychology major, but I asked her if I could do research with her and so we started putting out recorders on Santa Rosa Island.” Burdick continued his research in bioacoustics and biology, now a double major in biology and psychology.
Burdick explains that these listening devices “record their vocalizations and then we’re training a machine learning classifier to recognize them automatically.” Currently, they are putting the devices in locations where they know the California red-legged frog is present to collect recordings. Once this information is used to train the classifier, Burdick stated that “we can put recorders out in areas where we don’t know if they’re present.” These devices may help the conservation center track the population following their release. Data from the recorders would tell researchers whether the population is present, when they vocalize and which species are in the surrounding area, such as the invasive bullfrog.
Burdick anticipates that one day these systems will be available to everyone, much like bird sound-ID apps, allowing the public to aid in conservation by listening for and reporting species in their local area. “The big difficulty with endangered species is just like you don’t know where they are because there’s so few of them, but the more people you have out there looking for them, the better chances you have to know where they are.” He stated that he has been in contact with a developer of a California red-legged frog sound-ID system coming to BirdNet soon, who asked to use his recordings for classifier training.
When asked about his first realization that he has a talent that can be used to help the greater good, Burdick responded: “Probably with recording people.” He continues, “Doing that on my own trained me to do what I’m doing now, because you have to figure out a song from start to finish, and you have to engineer each section of the songand record everyoneand put it all together.” With hopes of studying drones, DNA and bioacoustics at UCSB after earning his bachelor’s from CI, Burdick plans to use his skills as a musician, researcher and engineer to support environmental conservation.
