Researchers are gathering information about the park's bats to help combat white nose syndrome.
White-Nose Syndrome and Bats
In the dark of the night, in the forests of Great Smoky Mountains National Park, there's something going on that you might not imagine. Thousands of winged crusaders are taking flight and providing an important service to the world. So who are these beneficial creatures? Bats. And these amazing animals are more deserving of our fascination than our fear.
Great Smoky Mountains National Park is home to at least 11 species of insect-eating bats, including the federally endangered Indiana bat. The mature forests and plentiful water here provide great roosting and foraging habitat for these flying mammals.
Bats are the primary predators of nighttime insects. They play a critical role in the health of ecosystems by consuming crop and forest pests. Bats fly swiftly and silently through the air, gobbling up insects like moths, beetles, and pesky mosquitoes. One Little Brown bat can eat up to 1,000 mosquito-sized insects in one hour, and one nursing female can consume her body weight in insects each night!
When winter arrives and insects are no longer abundant, many bats in the Smokies survive by hibernating in caves. Hibernation is a crucial time for bats, so a recently-discovered disease called white-nose syndrome has become a deadly threat to bats during this most vulnerable time.
KEVIN CASTLE: “White-nose syndrome seems to affect primarily cave-dwelling, insectivorous bats. It seems to be caused by a newly described fungus called Geomyces destructans. There may be other underlying causes of white-nose syndrome that are contributing to the bat deaths, and those are under investigation, but for now it looks like the fungus is the number one culprit.”
JOY O’KEEFE: “White-nose syndrome is causing fatalities for thousands of bats that roost in caves in the winter. It started in the northeast in 2006 and has spread from an epicenter near Albany, NY, in all directions, and it is moving south through cave systems. It has the potential to actually wipe out both federally endangered species of bats, such as the Indiana bat, and more common species of bats such as the little brown bat.”
The Geomyces destructans fungus thrives in the cold cave environments where bats spend the winter. It attacks the noses, ears, and wings of affected bats. Scientists theorize that this fungus irritates the bats making them restless and causing them to burn precious fat reserves that were meant to last them through the months of hibernation.”
During hibernation, bats are vulnerable, with their immune systems and metabolic activities reduced. Bats may lose as much as half their body weight as they slowly use up their stored fat during hibernation. If they wake too early due to white-nose syndrome, they could freeze to death or starve. Another hypothesis suggests that the fungus disrupts some of the bats physiological functions causing problems like dehydration which can damage the membranes on bats’ wings.
In a fight against time, researchers are looking for ways to stop the spread of white-nose syndrome. Record die-offs have already occurred in the Northeast. If the disease continues to spread at this alarming rate, some scientific models suggest that the Little Brown bat, which is one of the most common bat species and one of the hardest hit by white-nose syndrome, could face regional extinction in less than 20 years. There is still much to be learned about white-nose syndrome. No human illnesses related to the disease have been documented, but humans would certainly feel the effects of losing entire bat species which consume remarkable numbers of the insects we consider pests.
KEVIN CASTLE: “The Park Service is taking a very active role in dealing with the white-nose syndrome issue. Park service units across the country are contributing to white-nose syndrome surveillance methods by allowing researchers access to park units, by conducting surveys of their own, whether watching bats come out of caves or using acoustic equipment to listen to bats coming out of caves.”
In winter of 2010, Geomyces destructans, the fungus that is believed to cause White-nose syndrome, was found on two Little Brown bats in Great Smoky Mountains National Park.
Park biologists are taking steps to better understand bat populations, their habitat, and their health. Getting an accurate idea of the health and number of bats in the park can help park managers identify the impact this fungus is having here. Since the mid-1970s, biologists have conducted surveys to count bats within park caves during the winter hibernation period. These surveys allow the park to monitor changes in bat populations from year to year. Before and after entering caves, biologists follow rigorous decontamination procedures to minimize the possibility of spreading white-nose syndrome to uninfected hibernation sites, or hibernacula. Due to white-nose syndrome, all caves in Great Smoky Mountains National Park are now closed to the public.
DAN NOLFI: “The Great Smoky Mountains National Park has 16 caves with 17 entrances. One is the largest Indiana bat hibernaculum in the state of Tennessee, and it is critical habitat for the endangered Indiana bat. The Rafinesque’s Big-eared bat is a state species of concern in both Tennessee and North Carolina, and although we don’t have it in large numbers in our caves, we do have one of the largest known hibernacula populations in our mine complexes. During the summertime, the park uses another method—acoustic surveys—to monitor bat populations. Acoustic surveys are a non-invasive tool for counting bats and are conducted shortly after sunset when bats are in flight and actively feeding.”
BILL STIVER: “What we have here is a device called an anabat or a bat detector. We can strap it on top of our vehicle. We can drive down the road, and we can record the calls or the echolocations that bats are emitting. You can look on the computer and look at the frequency of the call and determine what species creates that call. We know that bats in the northeast have had in excess of 90% mortality related to white-nose syndrome. And so the goal with the anabat is to get some data on our bat populations before we have any major impact. And then we’ll continue these surveys the next several summers to see what impact if any white-nose syndrome is having on bats here in the Smokies.
Great Smoky Mountains National Park is working with other parks and protected areas across the country to protect bats and manage cave habitats... and we're asking for your help. For your own safety, please do not attempt to touch or handle any bat. If you see a bat that appears to be sick or injured, notify a ranger. Please do not enter caves in Great Smoky Mountains National Park. And finally, please spread the word about the importance of bats and the problems they face. By doing so, you'll be helping to encourage a brighter future for these fascinating creatures.
KEVIN CASTLE: “I often get asked the question of why people should care about bats, and I think there are a number of reasons. We know that they are important components of ecosystems. We know that they eat a lot of insects that might serve as pests whether for agricultural products or forest products that people are interested in. But for me, bats are just very interesting creatures that have a place in nature and I think we ought to respect them and protect them just because of that reason. I am optimistic that the efforts of the Park Service to save areas for bat populations and also to provide educational opportunities is going to be very important to recovery of the bat species that are being impacted by white-nose syndrome.”