One of the most serious wildlife issues today is a disease decimating bat populations in the eastern United States. Called white-nose syndrome (WNS), this disease was first discovered during the winter of 2006-2007 in caves near Albany, New York. It has since spread to caves in 15 states and Canadian provinces. More than one million bats have died and, in some caves, nearly 100% of the hibernating bats have died.
The disease is predicted to have a devastating impact on little brown bats, one of our most common species and threatens several already endangered species, such as Indiana bats and the big-eared bat. It is shaping up to be the largest mass mortality event in North American wildlife in recorded history.
The cause of WNS remains elusive but has been linked to a cold-loving fungus that forms a white covering on bats' faces, wings, and body. The fungus strikes bats when they are most vulnerable - during hibernation when their immune system is dormant. It causes bats to wake from hibernation using energy reserves long before spring comes. This results in death by starvation or freezing.
Although white-nose syndrome was named after the obvious symptom of white noses on affected bats, their wings may be the most vulnerable point of infection. Wing membranes represent about 85% of a bat's total surface area and help regulate body temperature, blood pressure, water balance, and gas exchange - not to mention the ability to fly and to feed.
Wind Cave National Park hosts eleven species of bats, eight of which are cave-dwelling. The few bats seen in Wind Cave are generally found along the Natural Entrance Tour Route. They enter by squeezing through the door at the cave entrance since they have difficulty going through the small Natural Entrance with its strong airflow. At this point white-nose syndrome has not affected the park's bat population. However, cave managers are keeping a watchful eye on the situation.
Even though WNS fungus does not affect humans, it may be possible for us to spread the disease from cave to cave which could, in turn, affect bats.
Wind Cave National Park has undertaken the following to prevent the spread of WNS fungus by humans:
– All backcountry caves in the park are closed. They may be entered by permit for management or research purposes only.
– All cavers entering Wind Cave, including visitors taking the Wild Cave Tour, must have clean clothing and caving gear. If they have been in a cave within an affected state, they cannot use that gear unless it is cleaned using accepted decontamination procedures.
– The park will conduct a survey to determine the use of caves within the park by bats. Resource managers hope to help establish a year-round record of bat usage of the park.
– The park is providing information about WNS to park visitors through brochures and by adding information to the park's website.
The cooperative response to this unprecedented wildlife disease has been tremendous as scientists work together to protect all bat species. The impact of losing our bat populations would be immense.
Bats are the primary predators of night-flying insects and play a vital role in maintaining a balance in nature. Different bat species hunt at different heights, preying on different kinds of insects. Larger bats eat various moths and worms that are harmful to agriculture and forestry. Smaller ones eat mosquitoes and other double-winged insects. Some species of bats can eat 600 mosquitoes in an hour! The Forest Service estimates that the die-off from white-nose syndrome means that at least 2.4 million pounds of bugs will go uneaten. This could result in a financial burden to farmers, possibly requiring more insecticide, raising environmental worries, and pushing up grocery prices.
Many plants, including tropical fruits, are pollinated by bats. Bats that eat fruit or flowers disperse seeds and pollinate flowers of more than 500 species of trees, cactus, flowers, and shrubs. If it were not for bats, the harvest of tropical fruits such as bananas, cashews, avocados, and pineapples would decrease. Bats are an important part of the world's ecosystem and need our awareness and protection.
For additional information regarding bats and white-nose syndrome visit:
The US Fish and Wildlife Service at www.fws.gov/WhiteNoseSyndrome/
The National Speleological Society's WNS page at www.caves.org/WNS/
Bat Conservation International at www.batcon.org/
The South Dakota Bat Working Group at www.sdbwg.org/