America's caves may not need permanent closure to protect their bat populations, now that researchers have a better understanding of a bat-killing disease.
An article in the scientific journal Nature confirmed that the fungus Geomyces destructans causes White Nose Syndrome in hibernating bats. While that was the prime suspect for an epidemic that's killed an estimated 1 million bats in 16 states and four Canadian provinces, getting a solid answer frees up resources for more study.
"Now we don't have to look at other variables, like some other virus, or health problems, or environmental contaminants factoring into why bats are getting the disease," said Ann Froschauer, White Nose Syndrome coordinator for the U.S. Fish and Wildlife Service. "There is more interest now in potential effects and economic impacts on insect populations and the forest and agriculture industry. Those things are starting to happen."
Bats earn attention because they eat whopping amounts of insects. A 2010 study concluded that the million bats already killed by White Nose Syndrome are no longer consuming between 660 and 1,320 metric tons of bugs a year. If America loses its bat population, the cost to the agriculture industry in additional pesticides was estimated to be $22.9 billion.
The disease set off alarm bells for environmentalists and cave explorers. The Center for Biological Diversity called for a nationwide closure of caves to protect bats. Cavers thought that was overkill, especially as they were the only people likely to pay attention to the condition of bats in the wild.
Alpine Karst Foundation president and Montana caver Mike McEachern helped lead a campaign to challenge the closure calls. Instead, he and others favored a strong policy of decontaminating caving gear and only using local equipment to prevent cross-country spread of the disease. The new research appears to support those tactics, he said.
"The study showed it can be spread from bat to bat," McEachern said. "But it also showed that when you take bats that are not infected, and put them in cages an inch apart from infected bats, they didn't succeed in transmitting the disease. So airborne dispersal doesn't appear to be a factor."
That lowers the likelihood that people exploring caves can carry the fungus to bats without touching them - something cavers avoid doing anyway.
In Missoula, U.S. Fish and Wildlife Service researcher Chris Servheen said Montana cavers will be recruited this winter to place temperature and humidity monitoring devices near bat caves to gather baseline data on the state's populations.
"A lot of folks come to Montana to cave, and there are some very spectacular caves in Montana," Servheen said. "We have hibernacula (bat wintering sites), and we have some of same species that are vulnerable to the disease. That's a concern, so it's really important we partner with the caving community in this process. They're very sensitive to ecological conditions in caves, like bats and blind fish and specialized insects. They're leaders in cave ecology."
National models predict little brown bats in the Northeast could
be functionally extinct in the next 10 years, Froschauer said. That makes getting a handle on White Nose Syndrome a pressing concern.
"As it progresses through the Southeast and Midwest, you get larger populations and more diversity than we have in Northeast," she said. "If we have the same mortality there, those pest control impacts could be exponential to what we see in Northeast. It would be affecting huge hibernacula with millions of bats rather than thousands."
So far there's no cure or preventative treatment to stop White Nose Syndrome. But McEachern said keeping cavers involved and in caves could help rather than hurt the research effort.
"If you don't have a policy that people support, you've defeated what you're trying to do," McEachern said. "Now we have a policy that cavers support. I'm pleased how it all came out."