Almost four years ago, in January 2007, biologists at the New York State Department of Environmental Conservation received a disturbing report: Dead bats lay on the ground near a known hibernation area.

According to Jeremy Coleman, national white-nose syndrome coordinator for the US Fish and Wildlife Service, when the state biologist went out to investigate, he found bats lying in the snow and others still trying to fly. Inside the hibernaculum, he found more bats with white fungus growing on their muzzles; others were already dead on the ground, and some were flying around haphazardly.

A quick check revealed three additional hibernation sites with sick bats—for a total of four sites within approximately 10 miles of one another. The following year, biologists found the fungus in three more states: Vermont, Connecticut and Massachusetts.

The fungus found on the bats' muzzles is only newly described, and scientists have just finished mapping its genome to learn more about it and the white-nose syndrome it causes in bats. Biologists also don't know its origin; it may have spread from Europe, though bats there aren't being affected in similar ways.

As white-nose syndrome devastates bat populations on the East Coast—it's killed more than one million bats already—biologists remain unsure how exactly the fungus affects the hibernating mammals.

Coleman says there are a number of hypotheses: The fungus may physically irritate the bats and prevent them from achieving hibernation. It might also damage their wings, dehydrating them and preventing them from maintaining their water balance, or else affecting other physiological functions.

"Another [hypothesis] is they're waking up and not necessarily starving to death, but they're agitated and recognize there is a problem in the cave," he says. They recognize a danger and feel compelled to leave the caves—"not because they're out looking for food necessarily, but because they're looking to escape and find someplace else to hibernate." In northern climes during the winter, he says, they inevitably die before finding new shelter.

One fact is all too clear, however: The fungus is spreading fast.

Coleman points out there is a difference between the fungus and the disease white-nose syndrome. In Oklahoma and Missouri, biologists have confirmed the fungus, but not the disease.

Coleman suspects that's because "we're finding it earlier in the cycle than we have in the past."

Nationally, the Fish and Wildlife Service is currently working on a plan, which is open to public comment, for managing white-nose syndrome in bats.

Here in New Mexico, state, federal and tribal agencies are preparing for the disease's inevitable arrival. Officials from a variety of agencies met in Albuquerque in November to discuss how to protect New Mexico's bats.

For the US Bureau of Land Management, which manages 13.4 million acres in New Mexico alone, protecting the bats is a major proposition. According to Donna Hummel, acting chief of the Office of External Affairs for the BLM's state office in Santa Fe, those lands include at least 1,000 caves and approximately 30,000 abandoned mines.

Based on an environmental assessment process, an interagency group has decided to have targeted closures, rather than close access to all caves and abandoned mines in the state. The BLM has identified 28 caves with known and significant bat populations—and closed access to those 28 caves.

"If we don't see that targeted closures are protecting bats, or if the fungus comes in, we may have no choice but to close all of them," Hummel says. "But at this time, we don't think that's necessary."

In September, the Southwest region of the Fish and Wildlife Service announced it was closing access to caves on all of its national wildlife refuges in Arizona, New Mexico, Oklahoma and Texas. There are only eight known caves on the 43 refuges in those states.

While the ultimate impact of white-nose syndrome remains to be seen, Coleman believes bats' ecological value can not be over-estimated.

"It's hard to express what the value of these organisms is, in part because we don't have a dollar figure to attach to the services that they provide—and it's hard to overcome the negative press bats have had over the years," he says. "But I don't think people understand how prevalent bats are in the environment: They are out consuming insects and performing important ecological functions that I'm afraid we're not going to fully appreciate until they're gone."