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Cave restrictions aim to thwart bat fungus

Tue., April 12, 2011

Officials say shorter season reduces risk to colonies

A popular cave near Chinook Pass in central Washington will be closed for part of the tourist season to help prevent the spread of the deadly white-nose syndrome in bats.

Boulder Cave attracts about 35,000 visitors each year who hike though coniferous forests along a short, National Scenic Trail to explore the 475-foot long cave. During normal years, the cave and the trail are open April 1 through Oct. 31.

To protect the cave’s bat colonies, visitation will be cut back to April 30 through Oct. 1, said Doug Jenkins, a spokesman for the Okanogan-Wenatchee National Forest.

Three bat species hibernate in Boulder Cave, including the rare Pacific Western “Townsend” big-eared bats. Just a few colonies of the tiny Townsend bats are known to exist in the Cascades. (The adults have a 10-inch wing span but weigh less than an ounce.)

“If white-nose syndrome should reach Boulder Cave, it would have the potential to wipe out an entire gene pool,” Jenkins said.

The longer closure will reduce the risk of people introducing the fungus that causes white-nose syndrome into the cave while hibernating bats are present, Jenkins said. The fungus spreads from bat to bat and from cave to bat. People can carry spores on their clothing or gear, transporting the fungus to new locations.

White-nose syndrome has killed more than 1 million bats in the United States and Canada since the first major bat die-off was documented near Albany, N.Y., in 2006. The fungus that causes the disease, Geomyces destructans, is believed to have originated in Europe. It’s been found as far west as Oklahoma, and wildlife biologists say it’s a matter of time until the disease reaches the Northwest.

Seventy-six bats were counted in Boulder Cave during the last field survey. In addition to Townsend bats, big brown and little brown bats hibernate there.

White-nose syndrome gets its name from the fungal growth on the bats’ nose, wings and ears. Scientists are still learning how the fungus affects bats but have observed unusual behavior during hibernation, such as bats flying outside during the day. During die-offs, bats with white-nose syndrome become severely dehydrated or lose critical fat reserves.

Visitors to Boulder Cave can help avoid the potential for spreading the fungus spores by staying on the trail, Jenkins said. At some point, the Forest Service might consider requiring anyone who enters the cave to wear protective clothing, which would be removed and decontaminated when they leave.

At this time, however, the effort is on education, Jenkins said. Forest Service officials hope to hire an interpreter to talk to Boulder Cave visitors this summer.

“People need to realize how critical bats are to our environment,” Jenkins said.

Bats play a beneficial role in nature by eating mosquitoes and other flying insects. Some studies suggest that bats save the U.S. agricultural industry at least $3 billion per year through pest control.

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