ACADIA NAT’L PARK — White-nose syndrome, an often deadly fungal disease, has drastically reduced the population of bats across much of North America, including in Acadia.
Wildlife biologists here are working to find the places that the park’s remaining resident bats like to roost so they can protect them from being disturbed.
The researchers also hope to gain insight into why there are still any bats left in Acadia.
“By a lot of estimates they should be all but gone,” said Bik Wheeler, a biological science technician. “But they are still here, even though in much depleted numbers.”
At dusk on summer evenings, members of Wheeler’s team go into the park and deploy nets across corridors where bats are known to fly in search of insects.
“We capture them and then attach a really tiny radio transmitter to them,” Wheeler said. “With the transmitter, we can locate them the next day. We’re focusing on those bats that are pregnant or lactating, and we track them to their roost.
“We want to find out where they are and what types of habitats are important. If we can figure that out, then we can further guide our operations in the park to avoid impacting those permanent populations.”
Wheeler said routine park activities such as trail work, vista clearing and building maintenance can inadvertently disturb or even destroy important bat habitats.
“We realize there is the likelihood of impacting the bat populations, particularly in their sensitive period, the maternity season,” he said. “So, we’re looking to find out where they are.”
Before the fungus that causes white nose syndrome was detected in Acadia about eight years ago, the park had large, healthy bat populations. The most common species were the little brown bat and northern long-eared bat. Less numerous was the eastern small-footed bat.
Today, the northern long-eared bat is listed as threatened under the federal Endangered Species Act. That bat and the little brown bat are listed as endangered under Maine’s Endangered Species Act, and the state lists the eastern small-footed bat as threatened.
The three species are closely related and they are very small, with some bats weighing only two ounces.
Wheeler describes the fungus that causes white nose syndrome in bats as “a pretty nasty beast,” because it is not spread just by animal-to-animal contact.
“Once a (bat habitat) is infected, the spores of the fungus can lay dormant for quite some time,” he said. “So, the bats can leave, but if they show back up again, they can get re-exposed. Even if a bat survives an infection, it can become re-infected by the fungus.”
Rebecca Cole-Will, Acadia’s chief of resource management, told members of the Mount Desert Summer Residents Association last week that protecting bats is important because they are a “fundamental keystone species.”
“You can thank bats if you don’t have mosquitoes in your back yard,” she said.
A bat can catch as many as a thousand small insects such as mosquitoes in an hour.
Cole-Will said white-nose syndrome has caused “something in the neighborhood of a 90 percent decrease” in the number of resident bats in Acadia.
“But the good news is that this year we are seeing a lot of healthy pregnant females,” she said. “So, we’re hoping that we’re seeing some kind of a (reversal) of the decline of healthy animals and that they are going to repopulate.”
Cole-Will said Acadia’s bat research efforts over the past several years have yielded “some of the best information about bats anywhere in New England.”
“And we have the best information about what has happened to bat populations in the aftermath of white nose syndrome.”