The number of bat deaths in the U.S. in just the last few years has been estimated at around 6 million and rising. The cause is a fungal infection called white-nose syndrome (WNS). The
fungus, Pseudogymnoascus destructans (formerly known asGeomyces destructans), that now infests many caves around the country was first identified and reported in New York in 2006-2007. It is currently found in hundreds of caves and mines ranging mostly throughout the Northeastern U.S. and spreading as far south as Alabama. It has also been identified in four Canadian provinces. Entire bat colonies have been decimated.
Many bat experts describe the impact as the gravest threat to bats ever seen. In some caves, there has been a mortality rate in excess of 90%. Nine hibernating bat species are confirmed to have fungal infections and at least five of those species are at risk of extinction. Some of those species are already on the U.S. Endangered Species list including the Indiana bat whose primary hibernaculum in New York has been affected.
I can recall as a child seeing many bats zooming around me on summer nights. Now I see none. Why does this matter? Bats play an important roll in insect control. A single insectivorous bat can eat 500-1000 mosquitoes an hour and can devour over 3000 larger insects per night. Illnesses vectored by mosquitoes are already on the increase. Bat losses could also mean a potentially huge problem for farmers trying to control damage to food crops and may result in the use of even more chemical sprays. The same holds true for the home vegetable, fruit and ornamental garden. Bats are also pollinators for certain crops, among them bananas, mangoes, peaches, figs, avocados and agaves.
It can take as little as two or three years from the time the fungus is found in a cave until the entire hibernating colony of bats is dead. A number of agencies, organizations and entities have now joined forces in an attempt to study and address the problem.
Just a few miles from me, the first man-made bat cave was recently completed. Described as a concrete box in a hillside, it’s almost as long as a basketball court and half as wide. It has high-tech surveillance cameras that detect heat without making any noise. The idea is to provide bats with a safe winter home that can be cleaned of any remaining fungus every summer to help keep white-nose syndrome in check. It has been reported that a number of bats did explore the new man-made cave and at least a few of them hibernated in the cave during the winter of 2012-2013.
On a more positive note, as many species of bats struggle against white-nose syndrome and possible extinction, natural adaption as well as micro-climates located within caves appear to be helping some species survive.
According to researchers at the University of California Santa Cruz, species that hibernate in dense clusters will continue to transmit the disease and their numbers will possibly decline to extinction. However, some species have surprised biologists by changing their social behavior. For example, the little brown bat appears to be going from a species that once preferred to roost in dense clusters to one in which most bats now roost apart from other bats. Scientific analysis suggests they are probably not going to become extinct because they are changing their social behavior in a way that will result in their survival, although in smaller numbers.
Gregarious species like the Indiana bat are predicted to continue to hibernate in dense clusters and their numbers will most likely continue to decline toward extinction.
Overall, some bat populations are bintang 4d stabilizing at lower abundances while others are on the way to becoming extinct. Data taken from bat surveys conducted between 1979 and 2010 shows a long period of population growth followed by dramatic declines caused by white-nose syndrome.
It is the hope of many that new research will provide more answers to this very serious problem. It is also hoped that natural adaption along with solutions like man-made bat caves will be successful in leading to a resurgence in the number of bats able to survive white-nose syndrome. Only time will tell. But time is short.