The little brown bat is among those threatened in the state.
Bunkers erected for war may soon offer sanctuary to Wisconsin's bats, threatened by deadly white-nose syndrome.
It's an experiment proposed by the Department of Natural Resources for the former Badger Army Ammunition Plant in southeastern Sauk County, near Devil's Lake State Park.
"In addition to turning the property into a new state recreational area, we're looking at other potential uses for what's there. This is one of them," says Robert Manwell, public affairs manager for the DNR's south central region.
Bats prey on biting and other insects, thereby protecting crops, and may also play an important role in reducing the risk of insect-borne diseases, such as West Nile virus, according to the DNR. The nonprofit Bat Conservation International estimates that a single bat can eat as many as 1,000 mosquitoes in an hour.
White-nose syndrome was discovered in 2006, in New York state. It's spread rapidly since then, killing as many as 6.7 million bats, the greatest decline of North American wildlife in recorded history, according to the DNR. In some regions, complete populations have simply been wiped out, with impacts cascading through ecosystems.
The fungal disease was discovered in Wisconsin last May. Tests showed that 2% of bats in one Grant County site had white-nose syndrome, named for its characteristic symptoms: white fuzz on bats' noses, wings and tails. Research suggests that it's spread by contact, such as when bats cluster together during hibernation.
Manmade structures, such as the bunkers at Badger Ordnance, offer hope. "As opposed to a naturally occurring cave or something like that, these bunkers could be disinfected once the bats leave in the spring," says Manwell.
Instead of rocky nooks and crannies, bunker surfaces are smooth and spacious. "You can enter it," Manwell says. "Some of them are big enough, for example, to drive a forklift through."
The former explosives storage areas are half above and half below ground, and provide most of the conditions that would be found in a natural cave, such as a relatively constant temperature and humidity level, which are necessary for overwintering.
"It's a very interesting idea," says Manwell. "We know that some of the bunkers are already being used by bats for roosting." Use of some bunkers for bat monitoring and study on a trial basis is being written into the master plan.
If successful, "we may try it on a permanent, larger scale if possible," says Manwell.
Badger Army Ammunition Plant, also known as Badger Ordnance, was built during World War II. At the time it was the largest munitions factory in the world. It served through the Vietnam War, after which it was idled and, in the 1990s, finally decommissioned. Cleanup of the sprawling site, more than 7,000 acres, has taken years.
"All of the surface soil, building materials -- things of that kind that had any contamination -- have been dealt with," says Manwell. "What remains, really, is monitoring the groundwater there. I suspect it will have to be monitored for many years yet."
Contractors continue to remove concrete rubble from building foundations at the site. "There was quite a bit of that out there, and that's actually being put to a beneficial use," says Manwell. "We've partnered with the Department of Transportation to use that concrete rubble as material for the rebuild of the Highway 12 bypass project that will go around Baraboo. So, we save some money and take care of the rubble."
The site includes three historic cemeteries. Of the rest, about 2,100 acres of the site have been transferred to the U.S. Department of Agriculture for dairy forage research. The Ho Chunk nation was recently successful in its bid to receive 1,600 acres via the U.S. Bureau of Indian Affairs. The DNR's 3,400 acres will be converted into a state recreation area to be called the Sauk Prairie Recreation Area.
"There's a huge range of possibilities there, just because of the size and the geography," says Manwell. "Hiking, biking, hunting, educational use, and there's quite a bit of discussion over whether there would be room for some ATV trails or possibly a shooting range."
The DNR is in the process of writing a master plan. A draft for public review and comment will likely be offered this summer.
Wisconsin's four cave-residing bat species are listed as "threatened," making it illegal to take action resulting in their death. The DNR advises people to not touch bats without wearing protective clothing, which should be disinfected afterward; the fungus that causes white-nose syndrome can be carried on clothes and the soles of shoes.
Sick or dead bats should be reported to the DNR's bat program website, dnr.wi.gov/topic/WildlifeHabitat/bats.html, which also offers suggestions on how to help the state's bat population.