ARNOLD AIR FORCE BASE, Tenn. (AFNS) --
On a cold, drizzly day in December, Arnold Air Force Base team members ventured into a wet, muddy cave to add to the data concerning white nose syndrome and tricolored bats.
The U.S. Fish and Wildlife Service proposed listing the species as endangered in September 2022 due to the impacts of WNS, a disease caused by the fungus Pseudogymnoascus destructans.
“WNS is caused by the growth of a fungus that sometimes looks like white fuzz on bats’ muzzles and wings,” said Dr. Amy Turner, National Environmental Policy Act, natural and cultural resources planner for Arnold AFB. “The fungus thrives in cold, dark, damp places and infects bats during winter cave hibernation. Impacted bats wake up more frequently, which often results in dehydration and starvation before spring arrives.”
The disease, for which there is no known cure, has been confirmed in 38 states since first being documented in the U.S. in 2006.
While there are no caves on Arnold AFB property, there are bat species that overwinter in the caves off base and are known to inhabit the forests of Arnold AFB the rest of the year.
The data collected in December and on a follow-up trip early this year will contribute to a study being conducted by researchers with Virginia Tech. The study is an investigation on how tricolored bats are surviving with WNS in some areas while in most of their range their population has declined.
According to the U.S. Fish and Wildlife Service website, “White-nose syndrome has caused estimated declines of more than 90% in affected tricolored bat colonies and is currently present across 59% of the species’ range.”
Locally, John Lamb, Arnold AFB biologist, has seen an 88.75% decline in capture rates of tricolored bats on base during summer survey work.
Arnold AFB team members took temperature measurements, swabbed bats and their surrounding environment and banded bats for future identification if recaught. The swabs and data are sent to the researchers for analysis, with Arnold AFB receiving reports of the results as a study participant. This was the second year that Arnold AFB has participated in the study.
While conducting studies of the bats and other wildlife is important, precautions must be taken to protect both bats and people. Only qualified biologists with a permit from the U.S. Fish and Wildlife Service may work with endangered species. In Tennessee, a permit is required from the Tennessee Wildlife Resources Agency to work with any wildlife species.
Biologists take care when handling bats to prevent transmitting diseases from humans to bats or between bats. They must also take precautions against transmission of disease from the bats to people, namely rabies. While cases of bats transmitting rabies to people is rare, according to Lamb, it is possible as all mammals can carry and transmit the disease. Biologists at Arnold who handle the bats receive rabies preexposure vaccinations.
The Virginia Tech study isn’t the first study of bats by Arnold AFB personnel. Since 2000, monitoring and various studies have been conducted of the bats that inhabit the forests on base and caves in the region.
“We at Arnold Air Force Base have been conducting bat research and conservation for more than 20 years with studies ranging from annual monitoring to radio telemetry tracking from airplanes,” Turner said. “Additionally, we manage our forests and waters to provide summer roosting habitat and foraging habitat for Tennessee bat species.”
Tricolored bats are just one of nine species of bats documented at Arnold Air Force Base. Six of those nine species are known to be susceptible to WNS due to hibernating in caves over the winter. They are the gray bat, Indiana bat, little brown bat, northern long-eared bat, tricolored bat and big brown bat. The red bat, evening bat and hoary bat live in forests year-round.
The gray bat and Indiana bat are classified as endangered. The northern long-eared bat is being reclassified from threatened to endangered effective Jan. 30.
“Gray and Indiana bats have been listed for many years due to declining numbers caused mostly by habitat loss and degradation,” Turner said. “However, the northern long-eared bat’s original listing in 2015 was due to declines caused by white-nose syndrome.”
In September 2022, a proposal to list the tricolored bat as endangered was announced by the U.S. Fish and Wildlife Service, citing white-nose syndrome as the primary factor for an increasing risk of their extinction.
“Another species, the little brown bat, is currently under a status review by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act also due to white-nose syndrome,” Turner said. “Currently, no forest bats have shown signs of infection, but monitoring will continue to determine if forest bats are susceptible.”
While some may find bats creepy, the winged mammals are beneficial to humans. The species that inhabit Tennessee are insectivores and help control insect populations, such as mosquitoes.
“It is estimated that insectivorous bats contribute $3 billion to $23 billion annually to the U.S. agricultural economy by reducing crop damage and limiting the need for pesticides, not to mention the reduction of pests in our backyards,” Turner said. “Most bats consume up to half their body weight in insects, while pregnant or nursing bats will consume 100% of their body weight each night.
“It is likely that the effects of declining insectivorous bat populations will influence insect populations, including possible increases in some geographic areas of insects that are economic and nuisance pests, likely leading to a need for more pesticide use.”
Knowing the potential impacts of a decline in the bat populations adds emphasis to the cooperative efforts by Arnold AFB team members and regional partners to gather and provide data for informed conservation decisions.
“Arnold Air Force Base personnel have made important contributions through cooperative efforts with partners, including the Tennessee Wildlife Resources Agency, The Nature Conservancy, U.S. Fish and Wildlife Service and others,” Turner said. “With the wide-ranging habits of some species – not to mention the 10,000 caves in Tennessee – cooperation and communication between agencies is important to accomplish big tasks that no one entity can do alone.”