Bat Caves Closed to Fight Deadly Fungus Foe
Little brown bats hang from a surface of a hibernation cave in New York. The bats' muzzles are covered with a white, powdery fungus.
Credit: Nancy Heaslip, NY DEC.

It's not likely you've visited any of the thousands of caves and mines in 33 states where bats are dying of a fungus infection. And you won't be visiting them now, either.

The U.S. Forest Service has closed them in an effort to control the fungus, according to news reports.

White-nose syndrome (WNS) is a poorly understood condition that, in the two years since its discovery, has spread to at least seven northeastern states and killed as many as half a million bats, according to Indiana State University researchers.

"Essentially these bats are hanging on the cave ceiling almost like a piece of food that you've forgotten about in your refrigerator and for whatever reason now they're getting moldy," microbiologist David Blehert of the U.S. Geological Survey told LiveScience in October.

The syndrome has baffled scientists since its discovery in the winter of 2006 in upstate New York, where hibernating bats were found with a mysterious white fungus growing on their faces and wing membranes. Hundreds of emaciated bats were found dead in and around their caves, suggesting that they had starved to death during their hibernating months, and affected populations commonly suffer 75 to 100 percent mortality.

Only in recent months have researchers began to untangle the mystery of WNS.

The killer is a member of a group of cold-loving fungi called Geomyces, Blehert's team announced in October.

They are still mystified by its relationship to such unprecedented bat mortality, according to a study of the situation led by Justin Boyles, a graduate student in biology at Indiana State University, published in March in by Frontiers in Ecology and the Environment.

The caves, in 20 states from Minnesota to Maine, plus caves and old mines in 13 Southern states, will be declared off limits later this month, according to an emergency declaration. Many of the caves are in the Monongahela National Forest in West Virginia.

Worldwide, bats play critical ecological roles in insect control, plant pollination and seed dissemination, and the decline of North American bat populations would likely have far-reaching ecological consequences, Blehert and his colleagues said. They noted that parallels can be drawn between the threat posed by WNS and chytridiomycosis, a lethal fungal skin infection that has recently caused precipitous global amphibian population declines.

"We are uncertain about the long-term effects of white-nose syndrome on North American bats, but we are quite concerned about future effects on bat populations wherever environmental conditions are conducive to growth of the fungus," Blehert said in October. "To manage and perhaps halt this disease, we have to first better understand it."

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