Hibernating little brown myotis

A small cluster of hibernating little brown myotis, each showing different stages of infection from the cold-loving fungus Geomyces destructans.

ALAN HICKS/Science magazine

For little creatures rarely seen, bats have stirred up a lot of Big Sky Country.

Recent research indicates Montana and British Columbia may have northern myotis bats – the same species the U.S. Fish and Wildlife Service has proposed for endangered species status because of a massive die-off in the eastern United States.

And acoustic studies hint that Montana bats may wake up from hibernation and fly about in sub-freezing weather – something unexpected in bat science.

All of this may feed into ongoing policy debates about how to protect bats while preserving the sport of caving – which has Montana cavers warily watching how the rest of the nation’s bat population progresses. A fungal infection called white-nose syndrome has killed millions of bats along the Eastern Seaboard westward beyond the Mississippi River. Caves in huge swaths of the nation have been placed off-limits.

“A couple years ago, the cavers were up in arms when the Forest Service said it intended to close caves in Region 1,” said Bryce Maxell, the senior zoologist for the Montana Natural Heritage Program. “Lots of biologists and agency scientists responded, and concluded that locking them out of the caves was not the right way to go. Now cavers are under contract with the Forest Service and Bureau of Land Management to gather information.”

Indeed, funding from a consortium of federal agencies, spurred by the white-nose syndrome threat, have ballooned the meager shelf of knowledge about bats. In Montana, the grants paid for more than 50 acoustic monitoring posts, which have been deployed throughout the state. They’ve nearly filled a 15-terabyte storage drive with nightly bat calls.

“Over nine months, we collected 100,000 bat passes,” Maxell said. “We’ve never really dealt with this huge volume of data. We found we needed an automated analysis software backed up with hand-checking to see what we had.”

Bat species have specific calls. By studying the nightly sound files, biologists can tease out which kinds of bats exist in what areas. Each monitor also tracks the temperature and time, so the report shows the conditions different bats fly at. That’s how we learned some bats fly when we thought they were hibernating.

“The fact a couple of species are regularly active all winter long does tip over some apple carts,” Maxell said. “It’s a classic situation, where we’d never really looked at this before. It turns out bats are a lot more flexible than we ever gave them credit for in past.”

***

A “bio-blitz” of naturalists scouring the Upper Flathead River drainage of British Columbia to catalog what lives there turned up evidence of northern myotis bats this June. The Flathead has extensive karst rock formations, which are common bat hibernating shelters. But caver reports from both sides of the border find few bats hibernating in the region’s massive caves.

“We think that particular drainage is one of the most important of any major drainage in the southern part of Canada,” said John Bergenske of Wildsight, a B.C.-based conservation group that participated in the bio-blitz. “The Flathead, because of its relative isolation – where it sits – we’re optimistic there may be a full array of bats for the western continent.”

That could have implications for eastern bat survival. Five of Canada’s eastern provinces have suffered die-offs because of white-nose syndrome.

South of the border, 22 U.S. states have suffered white-nose syndrome die-offs, and another five have reported traces of the fungus that causes the disease. A 2010 study reported at least 5.7 million bats have died from the disease, including more than 99 percent of the northern myotis bats in the Northeast.

“Bats are so wide-ranging, it’s difficult to get a handle on each species’ rangewide impacts from white-nose,” said Jeremy Coleman, the U.S. Fish and Wildlife Service’s white-nose syndrome coordinator. “We also know wind-energy development is whacking bats, and climate change is creating other unknown problems. It becomes a real challenge.”

A big part of that is simply knowing where the problem exists.

“We knew bats were missing from sites we knew about, but white-nose syndrome revealed many hibernating populations that were never counted before,” Coleman said. “We only found them because dead bats were spilling out of hillsides, or showing up at people’s houses, dying.”

That prompted the agency to recommend nationwide closures of public land caves in an effort to stop the spread of the fungus, which has been shown to travel on human clothing. The closure proposal stirred up cavers in the Rocky Mountains, who argued they shouldn’t be kept out of caves where few, if any bats were known to live.

Coleman said any closure plans would have been temporary as biologists worked to find a possible cure or defense for bat populations. But the debate also exposed the serious lack of basic information about the nation’s bats.

“Montana is not like the caves back east or south with large hibernacula,” said Missoula caver Bob Bastasz, who participated in talks with U.S. Forest Service Region 1 officials about how to manage Rocky Mountain caves. “The largest collection of bats in caves around here is under 2,000, which is nothing compared to hundreds of thousands or millions of bats back on the East Coast.”

And of the suspected 15 different species of bats in Montana, few remain year-round. Those that do often hibernate on cliff walls, trees or other places instead of caves.

An agreement reached last year had cavers agreeing to ensure they don’t take potentially fungus-contaminated gear into wild caves and decontaminate the equipment they do use. In turn, private cavers are helping develop a new database of public land caves and their bat populations.

Maxell said preliminary results from that information-gathering shows Montana has the temperature and humidity conditions to foster the white-nose fungus.

“How it might get here – who knows?” Maxell said. “We don’t know how much longer we might have. It might never get here. But the agencies realized if they didn’t collect this information now, if bat species decline, they can’t defend themselves on an (endangered species) listing issue. Then there’s the potential lost opportunity. If we don’t gather now, we might not be able to gather in the future.”

Reporter Rob Chaney can be reached at 523-5382 or at rchaney@missoulian.com.

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