IDYLLWILD, Ca. -- Dozens of frogs hopped from plastic containers into a mountain creek on Wednesday as researchers began a reintroduction effort that they hope can save the most endangered amphibian in California.
Mountain yellow-legged frogs were once plentiful in streams across the mountains of Southern California, but they vanished from most areas during the past few decades in a rapid decline that scientists attribute to loss of habitat, disease and other factors.
Researchers are now for the first time trying to help the species survive by releasing captive-bred juvenile frogs. After being raised in a laboratory, 65 young frogs swam free in the shallow ponds of Indian Creek, a stream lined with ferns, pines and incense cedars at the University of California's James San Jacinto Mountains Reserve near Idyllwild.
"We're at a critical point where there's probably less than 300 adults remaining in the wild, and they're spread across three mountain ranges and nine locations," said Adam Backlin, an ecologist with the U.S. Geological Survey. "Our first objective is just to stabilize what's left."
Backlin and another researcher waded through the muddy creek as they opened up the plastic containers and let the frogs out.
Beforehand, biologists bathed the 1-year-old frogs in a solution with naturally occurring bacteria that can help the frogs withstand deadly fungal disease.
Each frog also was fitted with a monofilament belt attached to a radio transmitter, which will allow scientists to track the animals' movements.
"I'm hopeful and excited because this frog hasn't been seen out here since the mid-1990s," said Frank Santana, research coordinator at the San Diego Zoo's Institute for Conservation Research. "This is the first big step."
Two years ago, scientists reintroduced tadpoles into the same creek, but those tadpoles apparently didn't survive. Trying with juvenile frogs will allow researchers to determine whether fully grown frogs have a better chance of survival.
Forty more juvenile frogs are to be released on Thursday, along with a 2-year-old adult female frog, which was raised at the Los Angeles Zoo.
Santana, an amphibian specialist who during his childhood enjoyed exploring creeks and catching tadpoles, has been working with mountain yellow-legged frogs for seven years at a laboratory in Escondido. He said it took a great deal of work to learn how to achieve effective breeding in captivity.
"We're going to learn a lot and hopefully get them established at different creeks in the future," Santana said. "Hopefully, the ecosystems will have a better balance once the populations become established."
The frogs feed on insects and are preyed upon by birds, snakes, raccoons and other animals.
Biologists say that Southern California once was home to more than 160 populations of mountain yellow-legged frogs (Rana muscosa).
Up until the 1960s, the frogs lived in Tahquitz Canyon and the creeks that emerge from it in Palm Springs. But now the species is considered to be extinct in the Coachella Valley, and is found only higher up in the mountains, generally at elevations above 5,000 feet.
Backlin said that museum records in California show the frogs were consistently collected by the hundreds each year until 1969, when the frogs suddenly stopped being collected.
"Something happened at that time, and then we have some further evidence to suggest that it was probably a disease issue that came through Southern California at that time," Backlin said. "This species has declined over the last 30 years tremendously."
If the released frogs survive, they will become the fourth group living in the San Jacinto Mountains. Two of those populations, however, are thought to consist of fewer than 10 animals, making it especially important to spread the frogs into other areas to increase their chances of survival, Backlin said.
The San Diego Zoo and the Los Angeles Zoo have more than 250 additional captive mountain yellow-legged frogs, some of which are to be released in the future.
The mountain yellow-legged frog is one of many types of amphibians in danger of disappearing throughout the world. A nationwide scientific study released last month found that populations of frogs and other amphibians are declining rapidly across the nation, including in California.
David B. Wake, an amphibian specialist and professor at UC Berkeley, said the species is considered the most endangered frog in the state and one of the most endangered in the nation. Wake, who is not involved in the reintroduction program, called the effort critically important and said he thinks there is a chance the frogs can recover.
The scientists in the creek were similarly optimistic as frogs jumped from their hands into the water. When the first frog landed in the water, Santana said: "Free."
Biologists from other agencies, including the U.S. Forest Service, watched as the frogs swam to hiding spots on the mucky bottom. After all of the frogs had been let loose, Backlin said he's optimistic about their chances of survival.
"Amphibian declines are this global epidemic right now, and this is just the first attempt in Southern California to really try this and see if it works, and there are a lot of other amphibians that could probably use assistance, too," Backlin said.
Scientists say the frogs start breeding when they are about 4 years old and can live up to 16 years.
"The best case scenario is that these guys will establish long enough to breed naturally on their own in this creek," Backlin said. "We probably won't see breeding from these frogs next year, but hopefully the following year."
The Desert Sun