They knew it was only a matter of time, but laboratory results have confirmed one of Illinois biologists' worst fears: Our bat population is in trouble.
White nose syndrome was first found in a bat hibernaculum in New York state in 2006. Since then it is has killed more than 5.7 million bats across the eastern third of North America from Canada down through the Appalachian Mountains. It was later confirmed in Missouri. The Missouri confirmation told biologists at some point they were bound to find infected bats in Illinois caves and mines. Biologists submitted samples to laboratories in early to mid February and tests confirmed white-nose syndrome-infected bats in Hardin, Pope, LaSalle and Monroe counties.
Joe Kath, endangered species manager for Illinois Department of Natural Resources, said in a media teleconference Thursday the caves where the infected bats were found in Hardin, Pope and Monroe counties are on private property and the state does not have permission from landowners to disclose their locations. The LaSalle County cave is on a State of Illinois-owned Blackball Mines Nature Preserve, he said.
In Hardin and Pope county caves biologists found little brown bats and northern long-eared bats infected with white nose, though there are at least seven bat species in the region susceptible to it, including the big brown bat, tri-colored bat, eastern small-footed bat, the endangered Indiana bat and the endangered gray bat. Throughout the state there are 13 endemic bat species and five of those are on either the federal or state endangered species list. Undoubtedly, all those species that use caves containing the fungus that causes the disease are in danger of infection, either by coming in contact with soils harboring it or from bat-to-bat contact. White nose gets its name by white fungus that grows around the noses of infected bats. The Latin name of the fungus is Geomyces destructans.
The fungus damages the connective tissues, muscles and skin of the bats. It causes them to wake early from hibernation hungry and thirsty. They fly out into the cold in search of insects to eat when there are none available.
Normally during hibernation bats awake from hibernation every 10 to 20 days, but WNS-infected bats may awake every three or four days, expending their stored winter energy in futile flights for food.
The diverse locations of the infected bats are particularly unsettling. Pope and Hardin are in far southeastern Illinois.
Monroe is in north central Illinois and LaSalle is in northwestern Illinois.
“We certainly were expecting it around the state, but for the first year, unfortunately, it is in four different sites,” Kath said.
None of the infected bats were found dead.
“Of the four sites where we did find infected animals, all the animals were still alive. There were no signs of massive die-offs or anything. That's basically what we would expect in the first year of discovery,” Kath said.
But in ensuing years, biologists anticipate the bat populations to steadily decrease as they have done since 2006 in the eastern states. People there who had seen bats at their ponds at dusk or in bat boxes are reporting not seeing them anymore.
People have nothing to fear from the disease itself; it cannot be spread to humans, pets or livestock. Bat behavior could be altered at some point, according to Jeremy Coleman, National White Nose Syndrome Coordinator with the U.S. Fish and Wildlife Service.
“In the summertime in the first year of infection, there will probably not be anything the public or bat community will be able to detect in bat populations. In a few years it's likely that bats will just disappear from the landscape,” Coleman said.
In mid- to late-winter in the eastern states some residents reported bats leaving their hibernacula early and trying to get into houses. Bats typically leave their hibernacula in April to eat, mate or migrate.
But those who enjoy seeing bats flying in the sky at dusk and enjoy the dent they take out of the mosquito population will be disappointed in a few years with disease mitigation.
Bats have ravenous appetites for mosquitoes – a single brown bat may consume 3,000 to 7,000 mosquitoes a night – and for other bugs detrimental to crops. A large bat population may consume thousands of tons of forest and agricultural pests annually, according to a press release from the FWS.
FWS National White-Nose Syndrome Communications Leader Ann Froschauer said some estimate bats' appetites save the farming industry $3 billion a year in pest control spray.
Since the disease has been in New York and other eastern state for about seven years, one would expect there would be an increase in the insect populations there. Scientists have not verified an increase due to bat population loss, Coleman said. Insect populations rise and fall very quickly due to weather conditions and climate change may be a factor.
Long-term data will be needed to confirm a direct correlation between declining bat populations and increasing insect populations. He said federal agencies have been talking about doing projects to compare insect populations today with those prior to the white nose discovery.
Destructive and invasive winter moth populations have been on the rise in the eastern states and some draw the conclusion the lack of bats could be a cause, Coleman said.
The white nose infection nationwide may be greater than anyone currently realizes. There are 20 states where white nose has been identified.
“I would venture to say Illinois bat populations have been impacted already. What we report on are winter hibernacula. They may travel hundreds of miles through the summer. They only hibernate half their lifetimes,” Coleman said.
“They are feeding and reproducing in the summer, so their zones of influence are higher than areas you see on a map.”
Missouri is the farthest location west for the discovery of the disease. The Geomyces destructans fungus was confirmed in soils in Oklahoma with no bat outbreak.
“It's possible it is much further west than we currently know,” Coleman said.
In order to prevent the chance of humans spreading the disease all caves on the Shawnee National Forest were closed to spelunking in 2009 and all those owned by the state were closed in 2010. A national decontamination protocol was also developed for those who enter caves.
Caves that are tourist draws, such as Mammoth Cave National Park, have created decontamination stations that clean the shoes of cave visitors.
Coleman said the federal government has funded research into ways to stop the spread of white nose syndrome and a chemical spray has shown promise. There is also research into pharmaceutical and biological measures to combat the disease.
“The ideal scenario is the bug that eats the bugs,” Coleman said.