For about six years,Cory Holliday,the Nature Conservancys cave specialist in Tennessee,has feared that white nose syndrome,a devastating fungal disease that kills hibernating bats by the millions,would come to Bellamy Cave. Last winter it did.
A few bats were found with the telltale fuzzy white growth on the muzzle,and Holliday knew it was time to act.
The disease,for which there is no treatment and no cure,was first spotted in New York in 2006. It spread to New England and has steadily moved south and west,crossing the Mississippi and just recently reaching Alabama. More than 5 million bats have died. The disease does not affect humans. But bats eat prodigious numbers of insects,and one study estimated that if the death toll continued to rise,the cost to farmers in increased use of pesticides would be in billions.
In Tennessee,a state with 10,000 caves and six species of hibernating bats,Bellamy is something special. It is the winter home,or hibernaculum,to 270,000 gray bats,listed as endangered partly because the entire species hibernates in only nine caves,three of those in Tennessee.
This is a species that could wink out in a few years, Holliday said.
So he and the Nature Conservancy decided it was time to dig in,literally. They built an artificial cave,roughly 80 feet long and 16 feet wide,with 11-foot ceilings. Completed this month,and buried under four feet of earth,it lies on a slope about 100 yards from Bellamy Caves entrance.
The conservancy is betting on the cave,a concrete bunker equipped with cameras and a temperature monitor. Most important,it can be scoured each spring after the bats leave,something that cannot be done in the complex ecosystem of a natural cave. The fungus takes a while to infect a whole colony.
White nose finds its way into a cave, Holliday said,and by year three youve got mass mortality. He hopes that disinfecting the bunker will stop the fungus in its tracks.
First,the bats have to come. Second,the cleaning has to work. Even at best,the bunker or others like it would be a refuge for some thousands of bats,while scientists scramble to find another way to fight the disease or surviving bats develop some resistance to the fungus. Although Holliday has consulted bat experts on every aspect of the cave – from temperature to airflow to varying the texture of wallshe believes the effort is a first.
If it works,the technique could be applied to abandoned mines and other built structures where bats hibernate. And whatever happens,the bunker is equipped with cameras and temperature sensors to study bats behaviour and see if their choice of microclimate affects their susceptibility to the fungus.
The lack of weapons to fight the disease is not surprising,since it was only in 2006 that it was first noticed.
The first step was determining the cause of the syndrome,which appears as a fuzzy white growth on the muzzles of sick and dying bats. David Blehert and his colleagues at the US Geological Survey identified the culprit as a previously unknown species of fungus that they called Geomyces destructans.
Hibernating bats have a lower metabolism and body temperature,and they are also densely packed together,so the fungus can spread easily. Sometimes bats fly in middle of winter when they should be hibernating.
For now,the finishing touches are being put on the Tennessee bat bunker. Recorded calls of bats will be used to attract them to the cave. Gray bats could begin to gather in the area in prehibernation mode any time now; most will be hibernating by mid-November. Win,lose or draw,the bet has been laid.