National Geographic : 2009 Apr
arrived in Sixty Lake Basin and swept from lake to lake, around a hundred of them, in a predict- able and deadly line. A er removing sh and restoring habitat, "to have this disease wipe the frogs out again---it breaks my heart," he says. Oddly, the fungus infects but doesn t kill tad- poles, which is why wriggling schools remain in otherwise lifeless ponds. Mountain yellow- legged frogs take some six years to mature. "Those tadpoles are from years ago---there s been no breeding in this pond since chytrid arrived," Vredenburg explains. "As soon as they transform into frogs, they ll die." Yet Vredenburg remains doggedly optimis- tic. He calls pond number 8 his victory pond. When he saw the frogs start to die, he removed some of the adults and treated them with an antifungal medication, then put them back. e population---though tiny---has now been stable for three years running. Vredenburg plans to apply his painstaking capture-treat- release method to animals in other ponds in Sixty Lake Basin. (Recently announced, a similar treatment project by a U.K. team aims to mitigate disease in the Mallorcan midwife toad of Spain.) If enough fungal spores can be cleared from frogs bodies, he says, the disease may lose its hold. Other sites are also yielding good news. Some amphibians aren t a ected by the fungus or can carry it without being hobbled. Certain Costa Rican tree frogs have skin pigments that allow them to bask in the sun without drying out, killing the fungus with heat. Most encourag- ing, Reid Harris of James Madison University and colleagues have found an innate defense in salamanders and some frogs: symbiotic skin bacteria that inhibit chytrid infection. (Some naturally occurring skin proteins show similar fungus- ghting properties.) "If we can augment the good bacteria to help lower transmission, Amphibians have evolved into 6,000 singular species as beautiful, diverse---and imperiled---as any on Earth. there may be time for the animals to ramp up their own immunity," Harris says. "And we wouldn t be putting anything into the environ- ment that isn t already there. Perhaps we can stop the epidemic outbreaks of chytrid." Upcoming Amphibian Ark projects may help researchers test these measures. In Panama, chytrid has only recently jumped the canal and begun a march eastward toward the still pristine Darién Province, where at least 121 amphib- ian species are known. One rescue facility is already up and running there; U.S. and Pana- manian partners are now planning another--- in part for research into how to boost enough healthful skin microbes in wild populations to stop the fungus cold. If the strategy works, the golden frog, for one, may be returned in healthy numbers to Panama s forests. Mean- while, in frog-rich Ecuador, Coloma and Ron have petitioned the government for an environ- mental audit of the Limón road project. Con- struction has ceased for now, and some habitat restoration may be done. ough perhaps too late to save the choked stream s animals, media attention there could help future land preservation e orts. WHY CARE ABOUT FROGS? "I could give you a thousand reasons," says Coloma. Because their skin acts not only as a protective barrier but also as a lung and a kidney, they can provide an early warning of pollutants. eir insect prey carries human pathogens, so frogs are an ally against disease. ey serve as food for snakes, birds, even humans, playing a key role in both freshwater and terrestrial ecosystems. " ere are places where the biomass of amphibians was once higher than all other vertebrates com- bined," says David Wake. "How can you take that out of the ecosystem without changing it in a major way? ere will be ecological conse- quences that we haven t yet grasped." " e story is much bigger than frogs," says Vredenburg. "It s about emerging disease and about predicting, coping with, and fighting things we don t fully understand. It s about all of us. Everyone should care." j Gaping defensively, a single Budgett's frog stands among many in the fight for amphibian survival. Researchers have ramped up the search for solutions, and each small victory breeds new hope.