Bracing for white nose syndrome
Western scientists take precautions against a deadly bat disorder
When the members of Boy Scout Troop 958 emerged from Fort Stanton Cave near Ruidoso, N.M., into the bright August day, they headed immediately to a nearby restroom. There they shed their muddy clothes, kneepads and gloves, stuffing them into plastic Wal-Mart bags. They took the bags to the cave bunkhouse, some distance from the restroom, and tossed everything into washing machines. Then they plopped their helmets into a barrel of disinfectant and swabbed their headlamps with disinfecting wipes.
The sanitation efforts were meant to help protect bats from a disease called white nose syndrome. It's killed over a million bats in the Eastern United States since 2006, but it hasn't hit the West -- yet. The disease is likely caused by a cold-loving fungus that strikes bats during winter hibernation, when their lower body temperature allows it to take hold. It's called white nose syndrome because it smudges the bats' faces and wings with white.
Similar fungi (think athlete's foot), annoy, but don't kill. Scientists suspect this particular fungus annoys the bats so much that it disrupts their hibernation: They wake up to scratch and groom it away, using up their fat reserves and starving to death before food becomes available in spring. The syndrome has wiped out nearly all of the bats in the caves it hits.
In the East, wildlife managers have been powerless to stop the fungus, which is thought to spread when bats rub against each other during hibernation, in maternity colonies and while mating. But humans may play a role in moving it from region to region and even from continent to continent. White nose syndrome was unknown in the U.S. before 2006, but bats with a similar white fuzz on their faces and wings had been seen for decades in Europe, where the syndrome does not appear to be lethal.
Land managers and wildlife biologists are divided on whether white nose syndrome will come to the West. Some believe it is inevitable, and that the threat to Western bats has grown since mid-April, when white nose syndrome was confirmed for the first time west of the Mississippi River, in a cave in eastern Missouri. "I think you would have to be terribly naïve to think that the sites in the West haven't been at risk," says Pat Ormsbee, a bat biologist for the U.S. Forest Service who serves as white nose syndrome committee chair for the Western Bat Working Group.
It's not just human travelers who might carry white nose syndrome from East to West; there are three bat species whose ranges span the continent, says Ormsbee. Back East, these bats mingle with others of their kind from hundreds of miles away. If Western bats behave like their Eastern cousins, it may give white nose syndrome a path to the West.
Some scientists believe that Western caves are generally too warm and dry to support the fungus, though, and that the region's bat hibernation colonies are too small and spread-out for white nose syndrome to take root. Scientists don't even know where most of the bat hibernation caves in the West are. "For the number of bats we see in the summer," Ormsbee says, "we don't know where they go in the winter."
The West is home to roughly 30 bat species, two of which are endangered: the lesser long-nosed in Arizona and New Mexico, and the Mexican long-nosed in New Mexico and Texas. Another rare species of bat, Townsend's big-eared, hibernates in Fort Stanton Cave. This bat has a scrunched-up face and ears that would do a jackrabbit proud. Its numbers have been declining, and two Eastern subspecies are federally endangered.
Bats are a key part of any ecosystem they inhabit. They eat bugs, literally tons of them. Bat Conservation International once calculated that one colony of about 20 million bats near its home city of Austin, Texas, ate 250 tons of insects a night. Given the importance of bats, "we have to do everything possible to defeat this thing," says Mike Bilbo, Bureau of Land Management cave program manager for Fort Stanton.
Although Fort Stanton Cave is about 1,000 miles away from the nearest infected site, the BLM is not taking any chances. Last year, the agency added a new condition to its cave-access permits: Groups must decontaminate their gear and clothing at home before entering, and use the field decontamination station near the cave's entrance upon exiting.
Another New Mexico cave system, Carlsbad Caverns National Park, is an unlikely site for white nose syndrome. The fungus grows at temperatures below 68 degrees Fahrenheit, but the Carlsbad bats roost in a part of the cave that is 70 degrees. And the bat that is known for its spectacular summer flights out of the cave, the Brazilian free-tail bat, doesn't hibernate; it migrates to Mexico. Nonetheless, the park is taking precautions. Visitors to the main cavern are not asked to decontaminate because the area is not bat habitat. But recreational cavers, who crawl in the smaller passageways where there may be bats, are requested to do so.
If spelunkers have visited any disease-stricken sites in the past five years, they are asked to leave all the gear and clothing they used in that cave at home. If they have caved anywhere in the East in the past five years, they are asked to follow the U.S. Fish and Wildlife Service's decontamination protocol -- the same process the BLM uses at Fort Stanton Cave -- before entering. The National Speleological Society, a cave recreation, science and conservation group, has asked its members not to bring caving gear from the East into caves in other regions, and to decontaminate gear and clothing between caves.
At least six Western states have added decontamination to their scientific collection permits, which biologists must obtain before they capture any bats for study, at the recommendation of the Western Bat Working Group. New Mexico and Montana merely require scientists to read the federal decontamination protocol. New Mexico also forbids the use of bat-trapping equipment that has been used in the East.
In Arizona, scientists are in the process of checking approximately 100,000 abandoned mines for bats before those mines are sealed for safety reasons, says Angie McIntire, bat management coordinator for Arizona Game and Fish. The department previously required scientists to decontaminate collection equipment between each cave -- a time-consuming process, given that some entered up to 30 caves a day. "We are evaluating how stringent we need to be," she says. It makes sense to ask for decontamination when researchers travel from East to West, but less so for researchers traveling within the Western states, she says.
Even Ormsbee, whose committee originally requested the stringent procedures, is pulling back. "At first, we thought we had to decontaminate everything. But now we just try to do the best we can under the circumstances. The objective isn't to sterilize 100 percent of all surfaces."
And scientists and land managers are taking other actions to prepare for white nose syndrome -- looking for the syndrome's tell-tale scarring on the wings of bats during summer surveys and conducting winter counts at hibernation sites to determine normal population levels. Whenever they examine abandoned mines, they report any new hibernation sites they find.
White nose syndrome is still an abstraction to most people, even those who care about the West's bats, but for BLM manager Bilbo, the threat is all too real. "We had a scare last year," he says. "Cavers photographed bats with white stuff on their faces." It turned out to be a false alarm -- powdery limestone from the cave walls.
"If humans are part of it, then we are doing everything possible" at Fort Stanton Cave, says Bilbo. "If it is spread by bats, then all we can do is wait."