hide captionThis young mountain yellow-legged frog, seen in San Bernardino County, Calif., is less than 1 1/2 inches long. Adults measure about 2 to 3 inches long. Scientists are trying to revive the frog population that has been decimated by drought, fire and diseases.
Scientists in California, working with the San Diego Zoo, are taking extraordinary steps to save an endangered frog. The mountain yellow-legged frog used to be found in nearly every mountain range in Southern California. But after years of drought, fire, floods and a deadly fungus, only about 150 adults live in the wild today.
Last summer, biologist Frank Santana put dozens of endangered yellow-legged tadpoles in a creek high in the San Jacinto Mountains, east of Los Angeles. They have been in cages the whole time, getting acclimated to the wild.
The tadpoles were rescued from a nearly dried-up pond not far from the stream. Years of low rainfall and a fire in the region had all but destroyed the endangered frogs' natural habitat.
Now, after the first winter snow, Santana has come back, ready to set them free. In chest-high waders, he steps into the frigid waters and opens the lids on one of the cages.
"All right, we got our first tadpole here — got him in the net," he says. "They look really good — they are swimming around, look nice and fine and fat and healthy. It's pretty awesome that they all survived for three months. We introduced them in late August, and they've been in the cages ever since, and we are pretty happy that they all survived."
Worldwide Frog Loss
Since the 1970s nearly 90 percent of the population of mountain yellow-legged frogs has been lost. Geologist Rebecca Fenwick attributes that loss to several reasons, including fires and floods, which are prevalent in Southern California. But she says it's also not as cold here as it used to be.
"In the last 15 years, it has gotten warmer in the winters," she says. "It doesn't stay cold in the same way, so the storms don't build up and create a large snowpack at this elevation."
Without a good snowpack, there isn't enough water to last through the summer, and the frogs — especially the tadpoles — haven't been able to survive. Fenwick says this creek is at a high enough elevation that it won't completely dry out, but habitat destruction is a problem not for just this species of frog.
Many species of frogs are on the decline worldwide, with about 30 percent of them in danger of extinction. Conservationists say not enough is being done to save these animals whose health says a lot about both the water and the land around us.
"They are disappearing much faster than any other vertebrate that we know of," she says.
Brian Gratwicke, an amphibian expert at the Smithsonian Conservation Biology Institute in Washington, D.C., says that since 1980, more than 120 amphibian species have vanished from the planet. In that same time period, only 5 bird species have been lost, and no mammals have gone extinct.
Gratwicke says thousands of people are dedicated to saving mammals and birds, but only a handful work to preserve amphibians. Gratwicke says that since frogs live in both the water and on land, they can be an early indicator for problems in either environment. He says that in the U.S., there are species of frogs that now survive only in zoos.
"I know that amphibians might not be as popular as other vertebrates such as birds and mammals, but they are, in my mind, a very important group of vertebrates," he says.