The Bat Cave: A radical bat rescue effort in Tennessee

The popularity of bats as a Halloween motif reaches back in time to the ancient origins of the holiday itself when bonfires were used to ward off “evil spirits.” The warmth and light offered by bonfires would attract insects, which would in turn attract hungry bats. So bats became, quite naturally, a feature of Halloween lore.

Unfortunately, the popularity bats enjoy at Halloween doesn’t help them out during the remaining 364 days of the year. Bats rank among our country’s most endangered wildlife, with seven in danger of becoming extinct in the United States alone. Their populations are declining as a result of habitat destruction (deforestation, cave flooding, vandalism, commercialization of caves), cave exploration disturbances, pesticide use, and “pest control” efforts. Bats also collide with wind-energy turbines; bat fatalities have been documented at nearly every wind facility in North America.

However, for cave-dwelling bats, their survival may actually depend on human intervention. More than one million bats have died since 2006 from an outbreak of white-nose syndrome, the result of a fungus (Geomyces destructans) that invades and ingests the skin and wings of hibernating bats. The disease causes bats to wake up more frequently during the winter, possibly because of water loss from damaged tissue. Bats aroused from hibernation burn up large amounts of limited winter fat reserves and often starve to death because of a lack of insects during cold months. In some cases, their wings are too damaged to fly. Dead or dying bats are frequently observed with white fuzz around their muzzles, hence the name “white nose syndrome.”

White-nose syndrome is believed to be transmitted from bat to bat, but there is increasing evidence that it may also be transmitted by humans carrying the fungus from cave to cave on footwear, clothing and gear.

Eleven cave-hibernating bats in the United States, including four endangered species and subspecies, have been affected by the disease or are immediately threatened by it: big brown bat, eastern small-footed bat, Indiana bat (endangered), little brown bat, Northern long-eared bat, tricolored bat, cave bat, gray bat (endangered), Southeastern bat, Virginia big-eared bat (endangered) and Ozarks big-eared bat (endangered).

The Bat Cave in Tennessee

Tennessee has more than 9,600 documented caves – more than any other state in the nation. These caves provide homes for 16 species of bats. Tennessee’s first documented white-nose syndrome cave was recorded in February 2010 in Sullivan County. Additional occurrences were recorded in 2010 and 2011. The Great Smoky Mountain National Park has also documented white-nose syndrome in a cave within the park.

Cory Holliday, cave and karst program director for The Nature Conservancy in Tennessee, says the spread of white-nose syndrome within the state is still limited, noting that the fungus has not been documented any further south than Van Buren County, Tenn.

Holliday is part of a radical project in Tennessee that aims to create safe havens for bats. The Nature Conservancy in Tennessee, in partnership with the University of Tennessee at Knoxville, and Bat Conservation International, has plans to build an artificial cave next to an existing natural cave in Middle Tennessee. The benefit will be that the artificial cave can be disinfected with anti-fungal agents to rid the cave of the fungus that causes white-nose syndrome, whereas the natural cave cannot.

“The fungus is really susceptible to a lot of things, such as heat and anti-fungal agents, but you can’t do what needs to be done in a natural cave setting because it would destroy other cave life forms, as well,” says Holliday. “This artificial cave is a pilot project, but if it works we are hopeful that we can build a lot of these things.”

Bats are constantly seeking new habitats and will move around looking for new places that meet their needs for roosting and hibernating, says Holliday. The purposefully textured, stone-like interior of the artificial cave is designed to perfectly replicate the limestone caves of Tennessee. The critical factors for the bats, says Holliday, are air flow and climate – the artificial cave must mimic a natural cave environment.

The design for the artificial cave, which will be located outside of Clarksville, Tenn., was recently finalized and the Conservancy expects to break ground in the spring of 2012. The group is urgently moving forward with the project despite the need for additional funds.

“The total cost to build the artificial cave is about $300,000, and we have raised about one-third of that,” says Holliday, who has been working on white-nose syndrome since 2009, when the killer fungus arrived in the South. “But we are forging ahead with the project because white-nose syndrome is so devastating.”

Bats account for about 25 percent of all mammals on Earth and provide enormous ecosystem services. They consume millions of pounds of night-flying insects each year and help keep in check bugs that are problematic for agriculture and forestry. Losing insect-eating bats could trigger massive insect explosions, which could have a catastrophic impact on agriculture and human health. A recent study by Gary McCracken, head of the Department of Ecology and Evolutionary Biology at the University of Tennessee at Knoxville, found that the value of bats’ pest-control services in the United States ranges from $3.7 billion to $53 billion per year.

 “I do have hope for the bats; however, it is very distressing to go to white-nose syndrome sites and see bats that are dead or bats missing from caves where they should be,” says Holliday. “At the same time, it also drives me come up with strategies to solve this problem.”

How to Help Bats Survive

Write to Congress: Effective response to this wildlife crisis has been hampered by a shortage of funding within federal and state wildlife agencies, says Holliday. He encourages the public to write letters to Congress in support of funding to support white-nose syndrome research, planning, coordination and management. To learn more, visit the Bat Conservation International website.

Help Fund the Bat Cave: To learn more about the artificial bat cave that will be constructed near Clarksville, Tenn., or to make a contribution toward the effort, visit The Nature Conservancy of Tennessee website or call the Tennessee Chapter Headquarters at (615) 383-9909.

Install a Bat House: Homeowners can provide safe bat habitats in their own backyards by installing bat houses. Learn more at the Bat Conservation International website.

Observe Cave Closures: Cavers are asked to observe all cave closures and advisories and to avoid caves or passages of caves containing large hibernating populations of any bat species.

Jenni Frankenberg Veal enjoys writing about the natural world and the people who work to protect it. She is rarely found without her daughters and a pair of shoes appropriate for hiking and rock-hopping in creeks. Visit her blog at YourOutdoorFamily.com.