April 12, 2013
Two years ago there were ten thousand hibernating bats in one of the largest bat caves in Pennsylvania, the abandoned Durham mine in Bucks County. This winter, PA State Game Commission biologist Greg Turner found just 23 still alive.
The decline is due to white nose syndrome, a fungus that has been killing bats across the state since 2009. Turner says white nose syndrome is the biggest threat to all seven of Pennsylvania's hibernating bats species, including Little Brown bats, which are under consideration for designation as a state endangered species.
Turner says white nose syndrome came to the U.S. from Europe. It interferes with the natural cycle of cave-dwelling bats, which need to hibernate for six months.
"Somehow this fungus causes the bats to arouse more frequently than they should be. By doing this they're burning through their fat stores for the winter," Turner explains.
Infected bats fly out of caves too early, and die. Turner says the fungus has caused 99% of Pennsylvania's hibernating bats to die. The fungus is highly contagious, and efforts to control its spread and treat infected bats have largely failed.
But there is some hope. The fungus may have reached the end of its spread in other parts of the U.S.
"It looks like there are a couple sites in New York that have bottomed out and are starting to show signs of potential increase," Turner says.
So far, Turner says he hasn't seen signs of rebound in Pennsylvania bat populations. But he and other researchers are looking for signs that bats that have resisted the white nose syndrome infection are passing off some beneficial survival traits to their young.