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White-Nose Syndrome: Will This Deadly Fungal Disease Cause Bats to Become Extinct?

December 06, 2013 | 3,327 views
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By Dr. Becker

You may have read or heard about the deadly white-nose syndrome that is destroying bat populations throughout the eastern U.S. Sadly, the disease is threatening to put one bat species in western North Carolina on the endangered species list.

The U.S. Fish and Wildlife Service (FWS) is proposing to list the northern long-eared bat as endangered under the Endangered Species Act. This tiny mammal, about half the size of a mouse, is found in western N.C. and upwards all the way into Canada.

There are seven species of bats in western N.C. that are susceptible to white-nose syndrome, and other species are being affected as well, including the little brown bat and the tri-colored bat.

Deadly White-Nose Syndrome is Decimating Bat Populations

White-nose syndrome first appeared in bats in upstate New York in 2006. It’s a fungal disease that causes a white fungus to grow on the faces, ears, wings and feet of hibernating bats. When effected bats come out of hibernation, they are severely malnourished and susceptible to starving to death before the insects they feed on emerge in the spring.

The reason the northern long-eared bat is so susceptible to white-nose syndrome is because of its size – about three to three and a half inches long and less than a half ounce in weight. This tiny bat also reproduces only one pup (baby) a year, which means the species doesn’t have much time to recover from disease.

The white-nose fungus irritates the bats’ skin, invading and degrading the tissue. It also burns off fat reserves, which is why the bats emerge from hibernation emaciated, hungry and thirsty. The fungus also eats into the skin tissue of the wings, which makes it difficult for them to fly well. Bats’ wings are also important for water balance and temperature control.

The fungus responsible for white-nose syndrome thrives in low temperatures and high humidity – typical climates found in the caves and mines where northern long-eared bats hibernate.

The fungus is spread from bat to bat as they hibernate in caves and mines. There’s no evidence to suggest white-nose syndrome affects humans, but people can transfer the fungus from one cave or mine to others on their shoes and clothing. In western N.C., the public is prohibited from going into any cave or abandoned mine on public lands.

'One of the most devastating wildlife diseases of our time.'

Since its first appearance in 2006, white-nose syndrome has killed an estimated 5.5 million bats in the U.S. and Canada. According to Sue Cameron with the FWS in Asheville, N.C., populations of the northern long-eared bat in the northeastern U.S. have declined by 99 percent in just seven years.

Biologists in western N.C. perform bat counts in local mines and caves during the winter months. A mine in Avery County that once had over 1,000 bats before white-nose syndrome, had 65 bats last winter. A mine in Haywood County that typically had 4,000 bats before white-nose only had 250 bats last winter.

According to Cameron of the FWS:

“Bats are a really important part of the ecosystem. They are a major predator of night flying insects. They eat mosquitoes and pests that can impact forests and crops, so people should really be concerned about this. Bats are pretty amazing animals and we hate to see losses of any species.”

And according to Gabrielle Graeter, wildlife diversity biologist with the N.C. Wildlife Resources Commission:

“People consider this one of the most devastating wildlife diseases of our time. It is affecting multiple species across a huge geographical range and spreading rapidly over a very short time. You can’t find the northern long-eared bat in the Northeast anymore.”

The N.C. Wildlife Resources Commission has been studying white-nose syndrome in several states for the last three years, looking for ways to slow the spread of the disease and searching for biological treatments that might reduce the effect on bats.

Unfortunately, they haven’t come up with much other than to advise people to stay out of caves and mines, put up bat boxes to provide safe alternative spots for bats to nest, and most importantly, learn to appreciate bats.

If a final decision is made to list the northern long-eared bat as endangered under the Endangered Species Act, the bat will be protected from “take” – harming, harassing or killing. Federal agencies will begin work to conserve the species and its habitat, and a recovery plan will be developed.

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