White-nose syndrome found in Maine bats

A little brown bat with white-nose syndrome.
Jonathan Mays | Maine Department of Inland Fisheries and Wildlife
A little brown bat with white-nose syndrome.
By John Holyoke, BDN Staff
Posted May 24, 2011, at 9:58 a.m.

BANGOR, Maine — A disease that could eventually kill three-quarters of the northeastern U.S.  population of hibernating bats has been confirmed in Maine for the first time.

State and federal wildlife officials announced during a Tuesday phone press conference that bats infected with White-Nose Syndrome were found in two Oxford County hibernacula, or wintering shelters, during surveys conducted during the winter hibernation season.

Until Tuesday’s announcement, Maine and Rhode Island had been the only New England States without confirmed cases of WNS. Last week Nova Scotia was added to the list of Canadian provinces — joining Quebec, Ontario and New Brunswick — where the disease has been detected.

And that’s bad news.

“In general, what we’re seeing across the northeast if we look sort of at the affected species as a whole, not just [Maine’s most common species], little brown bats, it’s somewhere in the 75 percent range, the mortality that the researchers are estimating,” Ann Froschauer, the U.S. Fish & Wildlife Service national White-Nose Syndrome communications leader, said.

Some hypothesize that a drastically reduced bat population will have far-reaching implications. Bats are voracious consumers of insects and a recent study published in Science magazine estimates that bats provide a pest-control service that saves the U.S. agricultural industry more than $3 billion a year.

John DePue, a Maine Department of Inland Fisheries & Wildlife biologist who conducted the hibernacula studies, said biologists were not surprised that the disease showed up in Maine.

“It was unfortunate. It was not disappointing, because we knew [the disease] was coming, but it kind of dashed a little bit of personal hope,” DePue said. “As a scientist, we were surprised it wasn’t here last year. We actually went back to one of the sites and checked twice [last year] because we didn’t believe it.”

White-Nose Syndrome was first detected in the United States in 2006 and has spread throughout the northeastern U.S. and Canada since. The disease, marked by a white fungus that appears on the muzzles of bats, spreads readily among hibernating populations and eventually can kill between 90 to 100 percent of the bats in a given hibernating area.

DePue said five dead bats were found during spring surveys conducted by DIF&W biologists at two Oxford County locations. Subsequent tests at the U.S. Geological Survey National Wildlife Health Center in Wisconsin showed that WNS was the cause of death.

Two of the eight species of bat that exist in Maine were found dead: the little brown bat and the northern long-eared bat. DePue said the little brown bat is the most common bat in the northeast and in Maine.

Froschauer said WNS has been detected in some bats that are listed as endangered, but can be devastating even for bats that are fairly common now.

“Science [magazine] has modeled that we may actually lose little brown bats in the northeast, they may be regionally extinct, in the next 15 to 20 years due to the mortality associated with White-Nose Syndrome,” Froschauer said.

Bats in the state’s third known winter hibernation hub, which is located in northern Maine, showed no sign of infection, DePue said.

Neither DePue nor two U.S. Fish & Wildlife officials would disclose the exact location of the bat colonies, citing the Federal Cave Protection Act of 1988. DePue said reducing human pressure on the bats was also a concern.

“We, the IF&W, don’t want to release that specific information getting out because we don’t want people going in to check them out. They are on private property, and we don’t want to disrupt the bats,” DePue said.

WNS is not harmful to humans but federal officials said they believe it can be spread from place to place by humans who climb in caves. The federal government in 2009 advised cavers to curtail their activities and pay particular attention to decontamination procedures in order to quell the spread of the disease, according to a DIF&W press release.

DePue said that biologists aren’t sure how many hibernacula exist in Maine, but said suitable wintering caves and mines likely are rare in the state. Fewer than 500 bats were hibernating in each of two Oxford County mines. The third site, which DePue said was not a mine, housed fewer than 100 bats.

“What little I know about the geology of Maine and what forms caves, we don’t have a lot of the rock that forms caves, so I don’t think we’re missing a lot [of hibernacula],” DePue said. “Certainly we’re missing some sites, but I bet it’s well less than a hundred. Probably less than 50.”

DePue said the DIF&W began systematic surveys of known bat hibernation sites in 2009, as WNS spread across the region.

DePue cautioned Mainers against touching or handling bats and encouraged those who find bats in their attics or camps to leave them alone until the end of the summer so that female bats will have the best opportunity to help their pups until they can fend for themselves.

Froschauer said the life cycle of bats presents one of the biggest challenge to the animals if WNS continues to spread unchecked. Bats live long lives — some can survive for 30 years — and females only raise one pup per year. Therefore, it would take a long time to re-establish a thriving bat population after a massive collapse.

A U.S. Department of the Interior press release issued on May 17 says researchers have identified a fungus known as Geomyces destructans as the “presumed causative agent” of WNS. A national management plan for WNS was also unveiled on May 17.

The USFWS says that bats with WNS act uncharacteristically during winter months, often flying outside during the day and clustering near the entrances of their hibernacula, or winter shelters. According to the fact sheet, more than 1 million bats have died due to WNS in the northeast and Canada, and some colonies of bats have suffered 90 percent to 100 percent mortality.

Of the 45 species of bats in the U.S., more than half hibernate in the winter. The 11 species that hibernate in caves — including four endangered species — are already affected or may be affected by WNS, the USFWS says.

For more information on white-nose syndrome in Maine, visit the MDIF&W website at www.mefishwildlife.com or send an email with your questions toifw.webmaster@maine.gov. Or visit www.fws.gov/whitenosesyndrome or www.nwhc.usgs.gov/disease_information/white_nose_syndrome.

http://bangordailynews.com/2011/05/24/outdoors/white-nose-syndrome-found-in-maine-bats/ printed on July 25, 2014