May 2, 2009

Caves Close Due To Bat-Killing Fungus

A fungus, which has reportedly already killed an estimated 500,000 bats, is causing the U.S. Forest Service to close thousands of caves and former mines in national forests in 33 states in an attempt to control the problem.

The problem was first noticed in New York and after two years had spread to caves in both Virginia and West Virginia. 99% of the bats infected have died.

While there is no reason to believe the fungus poses a threat to humans, bats have been dying at a startling rate from what scientists are now calling "white-nose syndrome", which is named after the white powdery substance on the face and wings of infected hibernating bats.

Experts say bats with white-nose syndrome wake up more often during their winter hibernation, which causes them to burn their stored fat. They are then compelled to leave the caves too early and cannot find insects on which they feed. Eventually, many starve to death.

Dennis Krusac, a biologist with the service's Southern region says that the researchers believe the fungus is spread from bat to bat, but it may be possible that people are carrying it from one cave to another on their shoes and equipment.

"We don't have the answers at this point," he says. "If we have answers in a year or sooner, we can open them back up."

The lack of information leaves experts to prepare for the worst possible scenario.

Becky Ewing, a Forest Service biologist says that the sites will be closed for up to a year after an emergency order was issued last week for caves in 20 states from Minnesota to Maine. She expects a second order to be issued later this month covering the 13-state Southern region.

The orders come on the heels of a March request for people to avoid visiting the caves in 17 states by the U.S. Fish and Wildlife Service.

Biologists are rightly concerned for endangered Indiana, Virginia and Ozark big-eared and gray bats that could become extinct. Pendleton County has the largest population of Virginia Big Eared Bats in the world, and white-nose syndrome is within five miles of one of their most densely populated caves.

Bats are extremely important in sustaining an ecological balance by keeping insects such as mosquitoes under control. Between April and October, they usually eat their body weight in bugs every night. Ewing emphasizes the importance of such a detail by noting that the loss of 500,000 bats means that an unbelievable 2.4 million pounds of bugs aren't eaten in a year. Bats also bring organic matter into the caves that other ecosystems subsist on such as invertebrates and small animals that are only found in one or two caves in the world.

New York caver Peter Haberland, who serves on the Northeastern Cave Conservancy's board, says caving groups should object to the temporary closures. He says, "For a period of a year, most people can deal with that."

Peter Youngbaer, white-nose syndrome liaison for the caving group National Speleological Society, believes that because many people exploring caves do not belong to an organized group, education is critical.

The Forest Service order states that people caught in a cave or mine will face up to six months in jail and fines reaching $10,000.

Youngbaer said he isn't convinced that humans are assisting in the spread of the fungus.
"There is no question that it's spreading bat to bat and spreading from bat to bat rapidly," he said. "If it turns out the fungus is living in the caves anyway ... humans moving around doesn't mean anything."

A study based on soil samples taken from 200 sites in 30 states should help clear this question.

The 910,000-acre Monongahela National Forest in West Virginia contains many of the caves in question. This week they announced that they would be extending the ban on high-risk caves put in effect last year. 

Despite having no evidence of the disease in Indiana, the Indiana Department of Natural Resources began closing caves Friday on state-owned property.

Krusac says that officials have closed all Great Smoky Mountain National Park caves, but that these orders will not apply to commercial caves on private property. 

Officials in the Ozark National Forest are now even debating whether to restrict access to wild cave adventures on the forest's Blanchard Springs Caverns.


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