ROCKPORT - Biologists with the Michigan Department of Natural Resources found no sign of a harmful fungal infection in 33 locations where bats are known to hibernate, including at Rockport State Recreation Area.
Along with assessing the state's bat population, biologists were looking for White Nose Syndrome, a fungus that attacks bats as they hibernate, DNR Wildlife Biologist Bill Scullon said. Its presence has been confirmed in 24 states and five Canadian provinces, and in some places it's caused 95 percent mortality rates in infected bats.
The DNR contracts with Eastern Michigan University to do the survey work, Scullon said. After decontaminating to avoid accidentally introducing it themselves, surveyors check hibernation spots, swabbing the bats themselves and checking their surrounding environment. They'll also shine an ultraviolet light around, as the fungus will glow under blacklights.
"We do what we can to try and detect it as early as possible, and try to document what we have for bat resources in Michigan so we know what resources will be impacted," he said.
Biologists are looking at sites where White Nose Syndrome might first show up in Michigan, Scullon said. While Rockport's bat population is small - only about 85 hibernate there - it's the most critical site on the Lake Huron shore. The fungus is already present on the other side of the lake, and while the site is not well-known, people do visit it.
"It's a good barometer for us of what's going on Lake Huron's shore," he said.
Scullon and others are working to improve the hibernation sites at Rockport, he said. Bats spend the winter in two abandoned conveyor tunnels used in a former limestone quarrying operation at the site. Alpena High School students welded together metal grates to block the entrances to these tunnels, allowing bats to get in but keeping people out. White Nose Syndrome can easily hitch hike on shoes, clothing and equipment, and people can unwittingly spread it after visiting contaminated areas.
Similar grates have been installed in abandoned mine shafts in the Upper Peninsula, Scullon said. There, bats take advantage of miles of underground tunnels from old iron or copper mines. A few sites are used by 50,000 or more bats each year.
While these old mine shafts are great places for bats to spend the winter, they're dangerous to people and a challenge for surveyors to reach, Scullon said.
"Some of these sites are quite involved to get to," he said. "They're out in the middle of nowhere, we're rappelling down into multiple levels, down hundreds of feet... we did one last winter where we spent ten hours underground at one site. There were several miles of underground tunnels."
Along with the grates, Scullon and others would like to push some of the crushed limestone at Rockport over one of the tunnels to better insulate it, he said. This would keep it warmer in the winter, making it a better place for bats to hibernate.
Several organizations are involved in the project at Rockport, including the DNR's Parks and Recreation Division, the United States Fish and Wildlife Service, the Michigan Sea Grant and Friends of Rockport/Besser Natural Area, Scullon said.
White Nose Syndrome thrives in environments where bats typically hibernate, Scullon said, doing well in temperatures below 65 degrees and in high humidity. Bats hibernate in humid places where temperatures are between 35 and 40 degrees, and their immune systems are suppressed during hibernation. The fungus irritates their skin, causing them to lose moisture and dehydrate. It can also wake them during hibernation, exhausting their energy reserves.
"Bats will actually emerge out of caves in the middle of winter time, desperate for food," he said.
Since White Nose Syndrome first was detected in New York, it's killed an estimated seven million bats. The Indiana bat, which is found in southern Michigan as well, might go extinct in nine years because of the fungus.
While Scullon and other biologists are keeping a lookout, it's likely White Nose Syndrome will eventually make its way to Michigan, he said.
"What we're trying to focus on right now is to try mitigating it as long as possible," he said. "In all likelihood, it is not something we can prevent."
Anyone looking to get involved can find out more at www.whitenosesyndrome.org, including decontamination directions, Scullon said. The state also has a website where people can report bats behaving strangely at www.michigan.gov/emergingdiseases, then by clicking "White Nose Syndrome in Bats" to the left.