Twenty percent of known caves in the United States are located in Tennessee.
Nearly one thousand species, mostly crustaceans, insects and arachnids, live exclusively in caves within the lower 48 states. Twenty percent of known caves in the United States (10,000+) are located in Tennessee. The federal government has not extended the protection of the Endangered Species Act to most of our nation’s cave creatures, even though most are highly vulnerable.
Protecting Cave Ecosystems
Preserving cave ecosystems represents one of The Nature Conservancy’s highest priorities in Tennessee, for good reason. Little is known about the animals living in this complex subterranean landscape. Caves contain critical habitat that bridges fields and forests with groundwater below.
In 2001, TNC worked with world-renowned zoologist Dr. Julian Lewis on the largest cave-survey ever undertaken in the state on 100 caves located in the Cumberland Plateau. The results revealed astounding results: 48 previously unknown species, as well as more than 150 insects considered globally rare. TNC uses this information to develop conservation strategies for these delicate ecosystems.
This work begins on land. Subterranean systems depend on water and debris entering from sinkholes and other entrances to nourish cave-adapted species. Areas surrounding caves are critical to animals that exit to feed at night, like bats and cave crickets. Alterations to the landscape and water table surrounding a subterranean system can affect both the quality and quantity of food and water reaching a cave.
Understanding White-Nose Syndrome in Bats
Tennessee’s best known cave dwellers are bats, including gray bats and Indiana bats which are both listed as endangered species. Depending on the species, bats use caves for hibernation, maternity and as a respite during migration, forming colonies numbering in the thousands and sometimes the hundreds of thousands.
Bats are especially sensitive to disturbances in caves. Waking bats during winter hibernation causes them to use energy stored to survive the season. Disturbances during summer threaten young bats in maternity colonies that have yet to take flight.
Over the past decade, an epidemic called white-nose syndrome (WNS) has devastated bat populations in the eastern United States and Canada. The culprit, an invasive fungus called Pseudogymnoascus destructans (Pd.), damages the wings of cave-dwelling bats. Infected bats wake more frequently during winter hibernation and exhaust critical stores of fat required to get through the winter. Most caves where the fungus has appeared have resulted in bat die-offs of 90 percent or more for vulnerable species.
In response, TNC works with partners to monitor bat populations in caves across Tennessee to determine how WNS is affecting bats and share data that will inform treatment of this disease. One project, which employs bacteria used to prevent bananas from ripening too fast, shows promise in stopping the growth of the WNS fungus. TNC continues to work with partners on this and other strategies seeking keys to controlling this disease.
Bat Behavior Research
In an effort to learn more about bat behavior while on the wing in Tennessee, TNC scientists—together with colleagues from the Tennessee Wildlife Resources Agency and Copperhead Consulting—executed a ground and air-based radio telemetry study on foraging patterns in 2018. A year later, the same team executed a new study focused on migration patterns.
When gray bats migrate, they can fly faster and farther, for hundreds of miles, usually seeking out caves for rest. This study sought to answer the question of whether gray bats assume a straight line of flight or follow river corridors during summer migration. The prevailing theory favored the latter.
The data told a different story, revealing that gray bats traveled between their hibernacula and summer roosting spots in a straight line. The information will guide future efforts to protect gray bats at every point in their life cycle, especially in light of wind development projects proposed in the state.
More on Cave Conservation
- TNC works closely with the National Speleological Society to achieve cave conservation, research and management goals.
- Learn more about bat houses and how to build your own.
- Get up-to-date information about White Nose Syndrome, an epidemic threatening cave bats.
- Visit the Tennessee Bat Working Group for more excellent information about Tennessee's bats.
Tennessee Caves and Karsts
Purchased Hubbard’s Cave, a premier bat cave in the Southeast, and built the largest cave gate in the world to protect gray bats. (Since then, TNC has built 34 cave gates, with two more expected in 2020.)
Performed the first comprehensive biological inventory of a Tennessee cave, with assistance from local recreational cavers, to reveal overwhelming biodiversity and establish the subterranean world as a new conservation frontier in the region.
Co-founded the Tennessee Bat Working Group, a coalition dedicated to sharing information between academia, land managers and the public.
Constructed the world’s first artificial cave specifically designed for hibernating bats.
Initiated a shared network of towers featuring technology that gathers information on aerial wildlife, including bats. Worked with The Conservation Fund to acquire priority Indiana bat habitat in East Tennessee.