MADISON — Wisconsin wildlife officials want to add four cave bats to the state’s threatened species list as a deadly fungal disease sweeps across the nation.
The Department of Natural Resources is racing to prepare for the appearance of white-nose syndrome in Wisconsin. The disease has killed more than a million bats across 14 states and two Canadian provinces since 2006, and ecologists fear it could drive some species to extinction.
The Natural Resources Board, which sets DNR policy, is scheduled to vote Wednesday on an emergency rule that would list the little brown bat, the eastern pipistrelle, the northern long-eared bat and the big brown bat as threatened in the state. The board also plans to vote on an emergency rule that would classify the white-nose fungus as an invasive species.
DNR officials hope to limit bat deaths at the hands of humans to keep bat numbers high, giving them a better chance of avoiding extinction if the disease hits.
But some who have seen the disease up close say it won’t do any good.
“I have absolutely no belief it will do a thing for them,” said Tom French, assistant director of the Massachusetts Division of Fisheries and Wildlife.
French said white-nose syndrome has killed about 10,000 bats in that state’s largest hibernating site since the winter of 2007-2008, leaving the ground littered with carcasses.
White-nose fungus grows on a bat’s nose, wing membranes and ears during the winter while they hibernate in caves and mines. Researchers believe it causes them to wake from hibernation and quickly consume fat. They flee their winter roost, known as a hibernacula, in a desperate search for food, but can’t find any in the winter and starve to death.
The syndrome was discovered near Albany, N.Y., in 2006 and has spread quickly as bats travel hundreds of miles in the summer months, causing dramatic population declines. Biologists warn the disease could all but wipe out the little brown bat in the Northeast over the next two decades. Earlier this month, the U.S. Fish and Wildlife Service closed caves on its refuge system to prevent the fungus from spreading through cavers’ clothing and instruments.
Minnesota has proposed listing the big and little brown bat as species of special concern ahead of white-nose syndrome. Vermont officials also are evaluating the status of all their bat species for possible listing as endangered or threatened.
The disease could strike in Wisconsin soon. It was detected last spring along the Illinois-Missouri border about 230 miles south of Wisconsin and in Ontario, about 300 miles from Wisconsin’s northern border, said Erin Crain, an endangered resources manager with the state DNR.
The syndrome could have enormous effects on Wisconsin agriculture, Crain said.
Wisconsin’s bat population is far larger than ones in surrounding states, partly because the state has such abundant water sources, DNR bat ecologist Dave Redell said. Some 300,000 bats hibernate in the state’s three largest hibernacula alone, he said.
The bats devour thousands of insects each evening and dramatic population drops would leave more bugs to spread disease and damage crops. Fewer bats also could lead to the death of other cave-bound creatures that depend on bats to bring in nutrients from outside.
A threatened designation would restrict people from transporting, possessing or disturbing the bats. The DNR also has prepared a conservation plan to minimize mortality, with provisions calling for purging buildings of bats before demolition and roofing work and prohibiting non-emergency summer repairs on bridges unless bats were purged before April 1.
Classifying the white-nose fungus as an invasive species, meanwhile, would restrict people from transporting, possessing or selling the fungus. It also would require anyone who visits hibernacula where the fungus is present or large bat populations roost to decontaminate their gear.
Jeannie Cunningham, who co-owns the Crystal Cave tourist site in Spring Valley, said all four species of bats that would go on Wisconsin’s threatened list roost in her cave and behind the insulation and ceiling tiles in her gift shop.
She said she’s worried regulators may eventually force cave operators to close, even though the disease is nearly impossible to control.
“They’re such a mobile animal,” said Cunningham, who sits on a National Cave Association subcommittee studying white-nose syndrome.
Crain, the DNR endangered resources manager, said the proposals don’t call for cave closures and the agency doesn’t have the authority to close private caves anyway.
Tricia Bross, an organic vegetable farmer in Rio, said a depleted bat population could mean a giant crop problem for growers like her who resist using conventional pesticides.
“I watch the bats at night flying around my place,” she said. “I know they’re getting mosquitoes and other things flying around at night. If they’re not there to eat them, we’re going to have more damage due to insect pressure.
“I’m very concerned. It’s all about balance. If you lose something, something else is out of balance.”