BAT-POCALYPSE

Greg Turner used to count bats by the thousands.

At an abandoned mine in Bucks County less than a decade ago, Turner, a mammalogist with the Pennsylvania Game Commission, says he used to find more than 10,000 bats spread over seven different levels. "When you got to the very bottom, there were literally thousands of them in one or two particular rooms," he says.

This might sound spooky. But Turner finds empty caves much, much spookier. "The sites are truly like ghost towns when you go back — there's just nothing left." Turner sighs. "When I go to that room that had 3,000 to 4,000 bats, there's two bats, or one bat." He counted about two dozen total throughout the mine the last time he was there.

That sort of decline isn't uncommon in Pennsylvania. "The largest site I counted went down to 40 from 100,000. I had sites with 50,000 that went down to single digits," Turner says. He sighs again. Every bat expert City Paper spoke to sighed a lot, actually — we're in the middle of a quiet and quickly spreading bat-pocalypse, and at the moment nobody knows how to stop it.

Why care about whether bats live or die, aside from the world getting slightly more depressing with every extinction? Prag­matically, bats have a vital, if often unnoticed, role in ecosystems.

"Bats are the night vacuum cleaners of the sky," says Brenda Malinics, who works with a number of wildlife rescues and is the main bat-rescue person for the Philadelphia area.

They can eat around a third of their body weight in insects each night, the equivalent of about 3,600 mosquitoes even for the tiny little brown bat. Bats vacuum up millions of tons of insects per year — insects that then can't bite people or destroy crops. A 2011 paper projected that bat depletion could end up costing U.S. farmers more than $3.7 billion a year.

Malinics has been working with bats for 25 years, and she says she's recently started getting a new kind of request: "I've had golf courses contact me pleading for help because of all the mosquitos — 'How can we attract bats?' 'We want bats at our country club!' Because people can't go outside during the day."

The reason behind all the empty caves first surfaced in North America seven years ago. A white fungus was noticed on the muzzles and wings of hibernating bats in a cave in upstate New York. It quickly became clear that the fungus was deadly, with mortality rates often above 90 percent of a colony. Since then, the fungus, called white nose syndrome when it affects bats, has spread to half the states. In many, like Pennsylvania, it's almost completely wiped out many species.

Turner has found the fungus in every cave and mine he used to survey. The last time the Fish and Wildlife Service made an estimate, in 2012, it said about 6.7 million North American bats had been killed by the syndrome. At the time, the fungus had been found in 12 states. Now, it's in twice that.

The spores were probably brought over from Europe by humans. It's a cold-loving fungus, one that only germinates at low temperatures. For the three species of migratory bats in Pennsylvania, it isn't a problem — an active bat's high body temperature keeps it safe. But when the other six species of bats go into hibernation — dropping their body temperatures and putting their bodies and immune systems into power-saving mode — it becomes lethal.

"The spore germinates and starts forming a fungal infection, and basically starts digesting the live cells of the wing membrane," says Turner. "Then as the fungus grows, it makes spores, then those spores get all over the bats next to them, so if they're in a nice cluster, pretty soon all of them will have these spores on them and all of them will have this infection."

This doesn't result in caves carpeted with dead bats like people picture, Turner says. The fungus causes the bats to waste stored energy, so that they use up their hibernation fat by January or February. At that point, says Turner, "They have a decision to make — stay in and die where they're at, or fly out and see what happens." Most fly out to search for nonexistent insects, where they freeze, starve or are picked off by predators.

A few are brought to Malinics. She says white nose syndrome isn't as visible as it sounds —"People think of the classic  white circle around the muzzle, but when white nose is exposed to warmer temperatures, it disappears" — but that she's seen plenty of bats with signs they've had it. They're emaciated, and "the wings look really ratty; they'll be almost like tissue paper, crinkly; sometimes they're shredded." Most of the time, she says, there's nothing she can do for them. She sighs.

"There's so much we don't know about bats," says Malinics. "They're not an animal that has been fully studied, because for a very long time they weren't valued for their importance to the environment. People just considered them vermin.

Now, everyone's saying, 'Oh my God, we've got to do something to save the bats,' and it may be too late, frankly.

"We never appreciated bats until they're gone," says Malinics.

Brent Sewall, an assistant biology professor at Temple Univer­sity, has published a few papers with Turner on white nose syn­drome. He says the situation is pretty bleak — there's no way to keep the fungus from spreading, no cure for it, and once fun­gal spores get into a cave, they're there for good. "In places like Pennsylvania, all or almost all of the suitable locations for hi­bernation have been contaminated with the fungus," Sewall says. With nowhere else to go, the surviving bats are "forced to go to locations where they're going to experience the fungus every winter."

But Turner and Sewall find a bit of hope in data they're about to publish.

"Back when this had just appeared in the state and the bats were in the mass-mortality phase, when we looked at the wings of those bats, about 60 to 70 percent of the wings were just covered in infection," says Turner. He and Sewall developed a method of using UV light to measure the amount of infection. Turner says they found that bats at sites where the fungus has been present for several years tend to have much less infection, on about 20 percent of the wing.

"We're hopeful that at some point it'll get to the same level as it is in the European range, where bats seem to do fairly well with it," says Turner. "They get infected over there, but they don't get heavily infected."

White nose syndrome likely came from Europe, you'll recall. "What's interesting is that though this fungus is widespread in Europe, it hasn't caused any [bat] population declines that we're aware of," says Sewall. He and Turner are seeking funding to look further into why, and how it may relate to the tiny survivor groups of bats in North America.

Sewall says his guess is that "the fungus probably has been in Europe for hundreds or thousands of years, and whatever damage it might have caused initially has long since passed."

He and Turner are also interested in how bat-mortality rates appear to bottom out on a similar timeline. "When we look at the epicenter area in New York, we see that around the sixth year, a few of the sites' populations start increasing. We were at year six in Pennsylvania last winter, and we're starting to see a little bit of an increase at some sites," says Turner. "So, hopefully, we're at rock bottom."

He quickly clarifies that those increases mean counting 10 bats instead of eight in caves that recently contained thousands. "Bats are very slow reproducers; a bat can live 30 to 35 years in the wild and produce one offspring per year," he says. "So it's going to take a long, long time for them to recover to anywhere close to where they were — probably 500 to 1,000 years."

That's why, Sewall says, it's extremely important to protect bats' foraging and cave habitats right now. "One of the most challenging things for a species to survive is getting hit with multiple threats at the same time," with disease, habitat loss and climate change generally being a big extinction-causing trium­virate, he says. "If we can reduce some of the other threats to bats, then they might be in a better position to respond to this new threat."
In 2012, the Pennsylvania Game Commission announced that it was considering listing three hibernating species of bats as endangered in Pennsylvania, but backtracked after legislators and timber, mining and oil industry reps threw a spotted-owl-referencing fit about the "disastrous" plan. A key opponent was state Rep. Jeffrey Pyle (Ford City), who later co-sponsored a bill to strip the Game Commission of its power to designate species endangered in the state.

"I'm not willing to sacrifice literally tens of thousands of jobs to save their little bats," said Pyle at the time.