Mark Twain National Forest caves close due to bat fungus

POPLAR BLUFF, Mo. -- Caves on Missouri Department of Conservation and Mark Twain National Forest land will be closed for one year following the discovery last week of white nose syndrome in Missouri. The fungus is blamed for the deaths of at least 1 million bats in the United States over the past four years.

This is the first time the department has closed bat caves for the fungus, according to Derek Shiels, cave biologist technician. The closure affects 80 of the department's 290 caves and all of its bat caves.

It includes Johnny Holt Cave and Mitchell Hollow Cave, both at Peck Ranch Conservation Area in Carter County, as well as Whisper Cave at Little Black Conservation Area in Ripley County.

The announcement represents a one-year renewal of closures issued last April for all of Mark Twain's approximately 600 caves and mines.

"We want to minimize the spread of this as much as we can," said Megan Harris, wildlife biologist with Mark Twain National Forest. "We're trying to be proactive."

Geomyces destructans is a cold-loving fungus that causes bats to emerge from hibernation early, Harris said. Depleting the bats' body fat puts them at risk of freezing or starving to death.

Little is known about white nose syndrome, and researchers have been unable to determine if the fungus is the sole cause of this change in behavior or part of a larger problem, Harris said.

The fungus is primarily spread bat to bat, Shiels said. For the Department of Conservation, the closures are more of an effort to minimize stress of already weakened bats.

"We want to reduce disturbance so we can give them the best chance of survival," Shiels said.

Studies done in Pennsylvania showed a 99 percent mortality of white nose-infected bats at a mine where the gate was repeatedly breached, according to the department. Mortality at a similar undisturbed location was only 85 percent.

Both agencies are working to develop monitoring plans.

Mark Twain National Forest began procedures last year to track the number and type of bats flying along specific routes. The information collected each year will be studied to determine trends in bat populations.

The conservation department would like to work with cave stewards who would monitor and report unusual activity at cave entrances, such as bats flying out in the middle of the day.

White nose syndrome was confirmed April 19 at a cave in Pike County in northeast Missouri.

This discovery came as part of hibernation surveys the department had been doing to look for visible signs of the fungus, Shiels said.

White nose syndrome has been found in the Little Brown Bat, the Northern Myotis, the Big Brown Bat, the Eastern Pipistrelle, the Small-footed Bat and the endangered Indiana Bat.

The Pipistrelle can be found in Johnny Holt Cave, the Big Brown Bat at Mitchell Hollow and the Pipistrelle, Indiana Bat and gray bat at Whisper Cave.

It is believed the syndrome was transported to the United States on contaminated caving gear from another country, Harris said. The fungus has also been found in European caves, but has not proved to be as fatal for bats there.

"If we continue to lose bats like we have ... it could have a huge impact on our agriculture," said Harris.

Bats reduce insect population and help keep crops healthy, she said.

Bat Conservation International estimates the bats already killed by the fungus would have consumed 700,000 tons of insects each year, equal to the weight of 175,000 elephants.

The Associated Press contributed to this report.