A Light at the End of the Tunnel for Endangered Bats
On a bright spring morning, about 20 biologists, researchers and students gather around the entrance to an abandoned railroad tunnel near Dubois, in central Pennsylvania. Everyone is in white Tyvex suits and rubber boots. They're gathered around Greg Turner, a biologist with the Pennsylvania game commission, who's previewing the day’s work.
The team is here to check on how little brown bats are doing. The species has been hit hard by white-nose syndrome, a decade old plague on America’s bat population. This team is looking at whether a commonly used chemical can slow the epidemic.
Wading into the tunnel in ankle-deep water, they get to higher ground about a quarter mile in. It’s pitch black, aside from headlamps and flashlights, which reveal tiny brown creatures wedged into crevices and cracks on the tunnel walls.
It's mid-March and these bats are still hibernating. White-nose attacks bats during hibernation. it disrupts their sleep pattern during winter, preventing them from storing up enough energy to survive. Turner shines his light onto clumps of bats, sometimes 3 or 4 of them piled into a small hole in the wall. Their heads are smaller than a mouse’s.
White-nose syndrome is caused by an invasive fungus — psedogymnoascus destructans — or Pd. Brent Sewall is one of the lead researchers on the project, a biologist at Temple University. He says the Pd fungus probably came to America from Europe or Asia around 2006.
European bats have a resistance to the fungus, but American bats don't. The disease has hit some species hard. Once common in Pennsylvania, the little brown bat is on the statewide endangered species list, and might be on the federal list soon.
We are just seeing massive declines… whereas you might have seen tens of thousands of bats previously, you might go to the same exact site today and only see tens
Scientists are trying lots of things to help these bats outs. Some are working on a vaccine. This group is trying something else. Last summer, they treated this abandoned railroad tunnel with the antifungal agent polyethylene glycol (PEG). It's a common nontoxic chemical found in products like toothpaste or laxatives. It doesn't kill the fungus, instead it tricks it into thinking there's a drought, so the fungus spreads more slowly. The idea came from a student of Barry Overton's, a biologist who studies fungi at nearby lock haven university. He says the treatment is just like spraying a field with insecticide.
Treating the Tunnels
Overton says he wants to see whether these treatments will have negative impacts on the state's native fungi. Microbial communities that live in Pennsylvania’s caves have been built up over millennia. Overton says he wouldn't want to disrupt these fragile ecosystems. But tunnels like this one were only created in the last century, so they could be fair game.
There's plenty of abandoned mines and plenty of railroad tunnels in Pennsylvania that we could treat, that could help get the population of bats up
Greg turner carries a ladder to a section of the tunnel where bats are packed into cracks and divots on the tunnel walls. He opens the ladder and climbs up, carrying a harvesting pole. It's a long thin rod with a piece of fabric wrapped around the end of it. He nudges the bats with the fabric tip, and they grab on with their claws. He then lowers the bats onto a net held by the team below. After capturing them, the team members put the bats, still half asleep, in small paper bags to weigh and measure. At first the bats are silent, but gradually they begin to stir, scratching at the bags with their claws.
Marianne Gagnon, a PhD candidate at Temple, is helping Sewall weigh and measure the bats. Little browns, she says, are worthy of their name.
The ones we had this morning were all between six and bit above 10 grams, for the little brown bats.
After each bat is weighed and measured, their wings are swabbed for DNA tests for Pd. Turner and Sewall then photograph each bat using a special UV light. Turner holds each bat wing down onto the light, while Sewall snaps a picture from a camera on a tripod. If there's any white-nose fungus on the wing, it will glow orange under the light. The orange is actually iron being pulled from the bat from a chemical secreted by the fungus. Some of the wings have orange splotches on them, signs of white-nose. But some look ok.
Turner says that overall these bats look like they're doing well.
The vast majority of them seem to have less infection, kind of a rate I'd put it equivalent to mid-season, so they probably did have a slight delay on getting exposed which is what we were kind of going for
He holds one of the last bats by its wings and lets it hang, until it starts flapping its wings.
The bat takes off down the dark tunnel. If all goes well, it will leave the cave in a few weeks, safe from white-nose for another summer. Turner says he will start to analyze his data when it comes in, in the next few weeks.
Reid R. Frazier is an energy reporter for The Allegheny Front, a Pittsburgh-based public media outlet covering the environment in Pennsylvania.