SUPERIOR, Wis. — The bat population in one Grant County, Wis., site declined 94 percent in a recent survey after the devastating white-nose syndrome fungus ravished the colony.
The Wisconsin Department of Natural Resources reported the news this week confirming that the disease is doing what it was predicted to do — kill bats and potentially wipe out entire colonies.
The DNR also said white-nose syndrome has been confirmed for the first time in Douglas, Iron, Pierce, Manitowoc, Sauk and Green counties.
“We are finding white-nose syndrome on a widespread basis, and the largest sites are all home to the fungus responsible for this disease,” said Paul White, Department of Natural Resources conservation biologist leading the Wisconsin Bat Program.
The DNR found evidence of the disease in 42 of 74 bat wintering sites inspected.
White-nose syndrome was first observed in North America in 2007 in a cave in upstate New York. The fungal disease spread fast, and has now been found in 28 states and five Canadian provinces and has killed more than 6 million bats. The disease was confirmed as killing bats in Minnesota for the first time in March when officials confirmed bats were dying outside the Soudan Underground Mine.
The deadly fungus is believed to have been carried to the U.S. from Europe by people who explore caves.
White-nose syndrome is named for the fuzzy white growth of fungus observed on the faces of infected bats. Those infected die from the disease, which causes wounds to the wing tissue as well as dehydration and starvation. It often first shows up as unusual behavior, such as flying during the day in summer or leaving caves during their usual winter hibernation, when no bugs are present for them to eat. They then die of starvation or exposure.
Bats can live more than 30 years in the wild but have a very low reproductive rate, which means it is very difficult for populations to rebuild after the disease hits.
Northern long-eared bats, a common bat in the Northland, have been placed under federal protections as threatened because they are very vulnerable to white-nose syndrome.
Experts say they are considering options to try to keep the disease out of specific caves, but once it enters it is impossible to eradicate.
The loss of bats, the only flying mammal, is considered troubling because bats play an important role in many ecosystems. A single bat can eat more than 1,000 mosquitoes in a single night. Bats are considered important agriculturally because of the huge number of insects they can keep away from crops, and in forested areas for reducing the number of tree-damaging bugs.
White-nose syndrome is not known to pose a threat to humans, pets, livestock or other wildlife.