White nose syndrome decimating bat populationsWritten by Don Hendershot
It’s only a matter of time before the fungal infection white nose syndrome (WNS) appears in North Carolina, say wildlife experts.
White nose syndrome is decimating bat populations across the country. It was first reported in the winter of 2006-2007 from a cave near Albany, N.Y. The disease, named for the white fungus that often appears on infected bats’ noses, muzzles and wings, is responsible for the deaths of millions of bats across a variety of species and is spreading rapidly.
WNS has now been detected from Ontario and Quebec, Canada down the eastern seaboard from Vermont to Virginia and Tennessee and just recently westward to Missouri and Oklahoma. Oklahoma presents pause for added concern because WNS was detected in a new species — cave myotis — that ranges across the Southwest to southern California and south to Mexico and Central America. At least 14 states have documented the disease.
Coming soon to N.C.
WNS has not, at this date, been detected in North Carolina. It has been documented in Virginia, West Virginia and Tennessee. And North Carolina Wildlife Resources Commission biologist Gabrielle Graeter has reported finding bats in Swain County with damage to their wings that is consistent with WNS. But, according to Graeter, biologist won’t be able to determine if the fungus is present until the bats are in hibernation this winter.
One of the sites in Tennessee, the White Oak Blowhole cave in the Great Smoky Mountains National Park, raises special concern because it is the largest-known hibernacula in the state for the federally endangered Indiana bat, and might serve as the overwintering site for nearly nine percent of the entire Indiana bat population.
Bill Stiver, biologist for the park, said that it would probably be next spring before biologists would have any idea about mortality rates in the park.
“We are monitoring bats this winter, but primarily at the entrance to the caves. We don’t want to exacerbate the situation by disturbing hibernating bats,” he said. “We probably won’t go into the caves until late February.”
Stiver said that because of cave closures across the park and questions from the public the park is focusing on educational materials. “We’re working on new exhibits for the visitor’s centers and a new podcast regarding white nose syndrome.”
Impacts from WNS
Endangered species like the Indiana bat and gray bat are clearly in danger, but even more disconcerting are reports that common bats like the little brown bat (the most common bat in the east) could also be in danger of extinction. Researchers from Boston University and the University of California Santa Cruz ran computer models suggesting that little brown bats could be extirpated from the Northeast in as few as 25 years.
WNS has proven to be incredibly lethal across the Northeast with mortality rates in many hibernacula approaching 90 percent. According to reports from the New York Department of Environmental Conservation, one of the worst hit caves in the Adirondacks was Graphite Mine. The report noted that the population of little brown bats in that cave dropped from 185,000 before 2006 to approximately 2,000 now.
The environmental impact of the loss of bats across the landscape is a giant question mark. Bats are, without a doubt, the most prolific and successful organic bug zappers around. Studies done at Boston University point out that the million or more of bats that have died from WNS over the past four years would have consumed more than 694 tons of insects each year.
Bill Stiver, biologist with the Great Smoky Mountains National Park, said that most of the research done to date has been with bat populations in the Northeast and that researchers here are holding their breath.
“We’re hoping that since it’s a cold-loving fungus, our bats across the Southeast will not see such adverse impacts,” he said. “But we honestly don’t know at this point. The next couple of years will tell us how our bats will be impacted.”