A devastating fungus is sweeping the planet, wiping out entire populations of amphibians at such a rate that biologists are helping pull together a huge "Noah's Ark" project to capture frogs, toads and salamanders and put them in safe places.
Various factors already have combined to cause more than 120 amphibian species to vanish since 1980, in what one biologist has called "one of the largest extinction spasms for vertebrates in history."
A third of the world's nearly 6,000 amphibian species are threatened - their populations weak and susceptible to disease. If they go, ecosystems will tilt out of balance and potential medical breakthroughs - such as potent painkillers or HIV inhibitors - could be lost.
It is hard to determine how many species have been affected by the fungus because they cannot be assessed fast enough, but it has factored into most of the recent extinctions and declines, said Bob Lacy, population geneticist at Illinois' Brookfield Zoo and chairman of the Conservation Breeding Specialist Group.
That leaves no time for anything but a triage attempt to get some of the animals out of harm's way until this "tragically unique" disease can be further studied and countered, he said.
"It is a race against time, and it's a matter of months," Lacy said.
Among zoologists, some have begun to face questions of which species should be saved and why.
"It's terrible. I've never experienced anything like this," said David Wake, a biology professor and curator of herpetology at the University of California at Berkeley, the first scientist to officially declare a pattern of global amphibian declines in 1989. "It's really an awful prospect."
When this fungal disease came along, amphibians already faced significant stress from global warming, pesticides and herbicides, acid rain and habitat destruction, experts said.
Some scientists point to them as bellwether animals for the Earth's health. Their slippery, porous skin absorbs moisture around them, making them more vulnerable to environmental changes than mammals, birds and reptiles with their fur, feathers or scales.
But chytridomycosis, caused by the chytrid fungus, is adding a confounding new level of peril that is pushing many species over the brink - even in areas mostly untouched by human hands.
