Chicago ? A devastating fungus is sweeping the world, wiping out entire populations of amphibians at such a rate that biologists are helping pull together a massive “Noah’s Ark” project to capture frogs, toads and salamanders and put them in safe places.

A variety of 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.

When this fungal disease came along, amphibians the world over 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.

Chytridomycosis was first identified in 1998 and is not well understood. As it moves around the globe, it has caused massive amphibian die-offs in Australia and hit the population of boreal toads in the Rocky Mountains.

The disease is filtering down Central America – one of the most biologically diverse areas on the planet – at a rate of about 17 miles a year, faster than a frog can hop to the next pond. With support from the Houston Zoo, Mauricio Caballero is leading an effort to build a field facility in Panama to preserve species, but the fungus caught up to his El Valle region before the roof was up.

“We knew what was going to happen, and now we’re seeing the frogs starting to die,” he said Monday. “We weren’t expecting it to hit so soon. We were predicting it was going to hit in the rainy season.”