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Bat Mines

In less than a decade, white nose syndrome has spread to caves in 22 states, killing nearly 7 million bats.

By Lindsay Renick Mayer

The day starts ominously.

I’m standing in a gas station parking lot by the side of a highway in Washington County, Maryland. With me are Deborah Landau, conservation ecologist for The Nature Conservancy in Maryland/DC; Andy Vecchio, ranger for the Maryland Park Service, and Dan Feller, western regional ecologist for the Maryland Department of Natural Resources.

We’re moments away from leaving for Roundtop Mountain, where we plan to search an abandoned mine complex for hibernating bats. That’s when Dan decides to point out that this adventure could be our last.

“Rocks bigger than this car,” Dan says, pointing to his Chevy Trailblazer, “come down in between the years when I’m in there. If you don’t feel comfortable, you don’t have to go in.”

The White Blight Rises

Despite Dan’s warning, no one balks. I woke up early — the Monday after the jump to daylight saving time, no less — determined to help survey bats that are facing a more pressing danger.

In less than a decade, white nose syndrome has spread to caves in 22 states, killing nearly 7 million bats. It starts as a fungus that invades the wing membranes of hibernating bats, waking the slumbering creatures when their energy reserves and food sources are scarce.

In the United States, the loss of bats is palpable. Bats are nocturnal insect-hawkers. A single little brown bat can eat a thousand mosquitoes per hour.

Without bats patrolling our night skies, pests can ravage farmers’ crops. White nose syndrome stands to cost U.S. agriculture up to $53 billion, according to an article in the journal Science.

Before the fungus hit here in 2010, nearly 400 bats hibernated at Roundtop. Today we’ll be lucky to find 70.

Descent into Darkness

Dan reviews the species we might see in the seven mines on our itinerary: little brown, big brown, small-footed, tricolor, Northern big-eared, possibly even rare Indiana bats. He instructs us to look closely for signs of the fungus — a white fuzz on the bats’ arms, legs or especially their snouts.

Somewhat self-consciously, I rock-surf down the steep path into the first mine. We descend one at a time down this black-diamond slope to avoid sending loose shale tumbling down onto the person ahead. And then we are in darkness.

Switching on our headlamps, we’re immediately rewarded with a big brown bat sighting. Big browns tend to hibernate close to entrances and remain relatively immune to white nose, Dan explains, though researchers aren’t sure why.

Though I’ve seen plenty of photos, I’m still struck by how cute this bat is — yes, cute — and I’m amazed that it can so casually hang upside down defying gravity. And it appears so fragile.

Dan reminds us to keep our voices down so we won’t disturb our dozing friend. We scan the surrounding walls, cracks and crevices before squeezing through a narrow passage.

The first thing we see inside the next chamber is a dead bat. Dan guesses it might be a little brown, but the body is too decayed to say for sure until he can perform a closer inspection in a lab. White nose has hit little brown bats particularly hard, with a mortality rate upwards of 90 percent in Maryland.

Origins of a Bat Apocalypse

Dan tells a story about the days before white nose erupted. In one cave in Cumberland, Maryland, he watched the bat population grow from 25 to 330 over 20 years.

“As an ecologist, I work a lot with rare, threatened and endangered species, and it’s not normal to see populations rebound like that with so little effort,” Dan says. “It was a very positive thing in my career.”

But in 2010 when white nose hit, that population plummeted to 27. And the next year, Dan found only one living animal.

Then, in the very shaft where we’re standing, Dan became the first to document white nose syndrome in Washington County. Andy adds that he met Dan just moments after that heartbreaking discovery.

“When he came out, he pulled up the photos on his camera, zoomed in and we could clearly see that some of the bats were impacted by white nose,” Andy says. “There was a sense of doom in the air.”

We continue on through each otherworldly passage. Remnants of a once-thriving limestone-mining operation lie crumbling or submerged in water. Mine four is particularly eerie, with steep drops either side of the shale piled up along the center.

Dan tells us he barely recognized this mine after a 2011 earthquake. Reaching the end of the fallen rock, we shine our lights out over, seemingly, a crystal-clear cave lake. A thin layer of calcium somehow, impossibly, is starting to grow over the water.

Doom and Gloom — and Hope?

At the end of the day, we’ve tallied 77 bats total: 51 big browns, 13 little browns and 13 tricolors. There’s more than doom and gloom in these mines, and our survey ends on a positive note.

In the last mine, where Dan came up empty a year ago, we discover 10 bats. And Dan says he’s seeing more hopeful signs in other tunnels he surveys.

Researchers are scrambling to better understand white nose syndrome in hopes of preventing mass extinctions. The data we’re collecting today is part of a state survey that Dan has led since 1990, but also will be included in a University of California study of how bat behavior and micro-climates in mines and caves affect the fungus’ prevalence.

In addition to these mines, which The Nature Conservancy bought and transferred to the state in 1989, Dan will lead surveys in another six caves and four tunnels. The Conservancy owns two of these sites, specifically to conserve bats and rare invertebrates.

“We’ve seen severe declines and even complete extirpation of bat populations in all our caves,” Dan says. Abandoned tunnels, however, seem to offer a safe haven for at least some bat species. “There is some hope that natural resistance could lead to a recovery.”


About the Author

Lindsay Renick Mayer is an associate director of marketing based in Bethesda, Maryland.

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