A cave fungus that’s killing millions of bats across the country is threatening to become a big problem for Minnesota’s timber industry.
The U.S. Fish and Wildlife Service will decide next spring whether to add the northern long-eared bat, which is being wiped out in places by the disease called white nose syndrome, to the endangered species list.
Such a decision would trigger a blanket prohibition against killing the bats, even accidentally. That would halt logging in much of the country during warm months, when the little animals roost in the forest and raise their vulnerable young in trees.
Only an estimated 5,000 of the bats live across a wide area of Minnesota, but national efforts to protect the species raise the specter of a showdown between regulators and businesses dependent on cutting down trees. Road and pipeline projects could be affected, and an end to summer logging would cut off crucial supply lines for sawmills and paper and strand-board mills.
“It would be devastating for us in the woods” said Scott Pittack, a logger with a crew of five based in Bovey, Minn. “I don’t know there’s a mill that could survive without summer wood … Plus, we all need a paycheck through the summer.”
First discovered in 2006 in New York, white nose syndrome has raced south through the Appalachian Mountains, along the Ohio River Valley to Missouri and Arkansas, and across Ontario to Michigan’s Upper Peninsula. It’s likely that more than 7 million bats have died, and entire colonies of long-eared and little brown bats have been destroyed in Vermont, New Hampshire and Pennsylvania.
No bats have died yet in Minnesota, but evidence of the fungus has been spotted on four bats in two places in the state — Forestville/Mystery Cave State Park in the southeast and Soudan Underground Mine State Park in the northeast — leading many to say it’s only a matter of time.
While the bats’ problem is white nose syndrome and not its habitat, the threat to the species is so severe that concern for maternity colonies in trees is necessary, said Rich Baker, endangered species coordinator for the Minnesota Department of Natural Resources. He just hopes the Fish and Wildlife Service allows for flexibility.
“Reproduction is the basic building block of a species’ survival, and so the emphasis on preserving reproduction, these maternity colonies, that’s legitimate and that’s warranted,” Baker said. “But it’s got to be done in a way that’s also reasonable, more of a scalpel approach than a sledgehammer approach.”
Need for defense
Northern long-eared bats are small, fuzzy and light brown with oversized dark brown ears. They hibernate in caves.
“During the spring, summer and fall, it uses forest, and in the summer it’s in the forest that they give birth,” Baker said.
Loggers won’t be able to guarantee they won’t accidentally kill a colony of mother bats who are giving birth. Newborn bats tucked into cracks and loose bark would be helpless.
“Those young can’t fly for up to a month after they’re born,” Baker said.
As soon as the bats are listed as endangered, accidentally killing or harassing them would become a violation of federal law. Federal regulators have proposed that between April 1 and Sept. 30 any tree over 3 inches in diameter must be inspected for a maternal colony of long-eared bats before anybody cuts it down.
Bats are critical for the state, wrote Tom Landwehr, commissioner of the Minnesota DNR, but loggers can’t survey every tree for them. The available data is “inadequate to support such a broad restriction,” he wrote in a July letter to each member of the state’s Congressional delegation.
“Given the number of trees removed annually throughout the state,” he wrote, “the recommended surveys are impractical and unrealistic.”
Halt to logging?
Georgia Parham, a spokeswoman for the U.S. Fish and Wildlife Service, said the instructions for how to protect bats by inspecting trees are not a rule, but a guideline.
The agency wants help from industry and state conservationists to create rules that make sense. It is accepting comments on its proposal until Aug. 29, and will hold online information sessions starting Tuesday. A final decision is scheduled for April 2.
The regulatory options are complicated, however, because the Endangered Species Act is a “blunt instrument,” said Baker.
If regulators list the bat as endangered, businesses could seek “incidental take permits” that allow accidental killing of the animals. But those require a detailed study of habitat, how many bats would be killed, economic analysis and environmental review. “It’s a three- to five-year process,” Baker said.
Federal officials could also list the long-eared bat as threatened instead of endangered, which would give regulators more leeway to allow logging under certain circumstances.
“It’s a complete crapshoot,” said Wayne Brandt, spokesman for Minnesota Forest Industries.
It’s not just long-eared bats that face a threat to their survival. The more common little brown bats — of which Minnesota has an estimated 50,000 — are also highly susceptible to white nose syndrome.
It shows up on bats’ faces as if they’d been dunked in powdered sugar and causes them to wake up in the winter when they should be hibernating. Researchers found this year that the fungus lives in caves even without bats around. It grows into the bats’ snouts and wing tissue. The fungus is not harmful to humans, though humans can spread it.
Scientists across the country are launching studies of the disease and the little-understood bats that suffer from it.
Baker is trying to get legislative approval for a $1.25 million grant for the DNR, which already has a small project going. Enbridge Energy, which is trying to build a pipeline across northern Minnesota, has conducted a study of northern long-eared bat habitats. So have state conservationists in Wisconsin and Michigan.
But researchers are working from behind.
Bat populations are dropping in Missouri, where the disease is now endemic. The fungus was confirmed in Arkansas this past winter, and bats in Wisconsin just across the Mississippi River from Dubuque, Iowa, have died from the disease.
Park rangers started finding dead bats in Mammoth Cave in Kentucky in 2013, where 25,000 bats of various species hibernate in the world’s largest cave system and travel as far as Michigan. Rick Toomey, director of the Mammoth Cave International Center for Science and Learning, said he would be surprised if the dominant gray bats there don’t start dying in large numbers this winter.
Bats eat half their weight in insects each night, fighting major agricultural pests that afflict cotton and corn crops, Toomey said. If they aren’t around to eat the insects, farmers will end up using more pesticides, Toomey said. Bats also play a critical role in pollinating many crops and other plants.
“The loss of the bats,” he said, “is going to shift major things in the ecosystem.”
Adam Belz • 612-673-4405