Tennesseans fight illness in bats
CLARKSVILLE, Tenn. — Sparks flew in the air as Kristen Bobo fired her welding gun at the thick metal bars spanning the entrance of a cave in Montgomery County.
The angled bars are
Tennesseans fight illness in bats
CLARKSVILLE, Tenn. — Sparks flew in the air as Kristen Bobo fired her welding gun at the thick metal bars spanning the entrance of a cave in Montgomery County.
The angled bars are designed to let bats easily fly into the cave while keeping out people who could vandalize or disturb the unique habitat.
Interactive: Peek inside an artificial bat cave
Interactive: Understanding white nose syndrome in bats
"If it's hard for me to get in, it's going to be even harder for the vandals," Bobo said.
The Cookeville woman has built dozens of cave gates during the past decade, but never has her work with conservation groups to protect bat habitats been more crucial. In recent years, a deadly fungus has killed millions of bats across the eastern part of the country and is now extending its reach in Tennessee and nearby states.
Erecting gates across several entrances at the cave just outside Clarksville is one of the latest efforts by The Nature Conservancy to find ways to combat the bat illness known as white-nose syndrome.
The fungus, which attacks bats in hibernation, was first identified about eight years ago in New York and has since spread to the Midwest and as far south as Mississippi.
Last summer, vandals searching for American Indian remains dug scores of holes throughout the cave. Aside from damaging the priceless archaeological site, the disturbance made it harder for the bats to flourish in the cave, said Cory Holliday, director of the conservancy's cave program in Tennessee.
During the summer, as many as 10,000 mostly male bats use the cave to sleep during the day. But the conservation groups want it to eventually be a place for female bats to raise their pups, Holliday said, helping boost the population of a creature that plays an important role in the environment.
Bats' voracious consumption of flying insects keeps those populations in check. A population of a million bats eats 694 tons of insects per year, according to the conservancy, and their value to Tennessee agriculture has been estimated at more than $313 million annually.
In recent years, the cave often has been little used by the bats for winter hibernation, Holliday said. Instead, the winged mammals found other places to spend the winter to avoid the cave, which has been so prone to disturbances.
That's when human activity can do the most damage.
"When they're here for the winter, they're on a pretty tight energy reserve," Holliday said. The bats must stay asleep to conserve energy to make it through the hibernation.
"A group comes in for 30 minutes and (the bats are) awake the whole time," he said. "They have two grams of fat to get through the winter. It doesn't take long to burn through that."
A bunker for bats
The gating isn't the only effort that the conservancy has undertaken in an attempt to beef up local bat populations. It's also about two years into an experiment to find out whether bats will take up residency in an artificial cave it built in Montgomery County.
The concrete and rebar structure is sort of like an underground bunker, sitting just below the surface of a hill not far from other caves where bats nest. The conservancy completed the $300,000 structure in August 2012.
Conservationists can clean out the man-made structure between hibernation seasons, preventing the white-nose fungus from taking root.
"It takes about three years for the fungus to make any impact," Holliday said. "When the bats come in in the fall, if we can get them to hibernate there, they're coming into a clean environment."
The only clue to its existence is a pine plank portico that covers the opening for bats. Down below, netting and specially formed concrete on the ceiling provide crevices for the creatures to latch on. Cameras and microphones are rigged throughout the space to capture every squeak and flutter of a winged visitor.
But so far the group has had little luck getting bats to hibernate there.
"We've had some bats come in and roost, but they're coming in midwinter," Holliday said. "The bats that come in the fall, they check it out but then they take off."
Part of the problem, Holliday said, is the temperature at the bunker during the time bats look for a spot to spend the winter. A thermometer inside the artificial cave found it was about 15 degrees warmer than nearby natural caves.
This fall, the conservancy is toying with the idea of using air conditioners to cool off the bunker during those early fall weeks.
"It's a work in progress," Holliday said.
Other recent scientific developments also show promise at finding ways to fight the fungus in natural caves. Researchers at Georgia State University are testing bacteria that emit fumes noxious to the fungus but apparently harmless to the bats. Work is still underway to ensure the bacteria are safe for the ecology of natural caves.
"White-nose syndrome is still really new," Holliday said. "We're learning more literally every day. So our techniques and strategies are changing also."
Reach Josh Brown at 615-726-5964 and on Twi