NORTHWEST ARKANSAS — Confirming the cause of a disease that’s killed more than a million bats in North America will help wildlife officials develop a management plan, but it won’t mean the caves in Northwest Arkansas and other parts of the state will reopen soon.
Most cave enthusiasts who visit Devil’s Den State Park in Washington County already know about the bat-killing disease known as white-nose syndrome and aren’t expecting to enter any of the park’s caves, said Tim Scott, assistant park supervisor.
Most caves in the state have been closed since 2009 to curb the spread of the disease, which can be carried by humans and passed on to bats. The disease has been documented in Tennessee, and suspected in Missouriand Oklahoma, but no cases have been documented in Arkansas.
Rebekah Spurlock, park interpreter, said all of the 60 sandstone fracture caves at Devil’s Den State Parkare closed, and the popular Ozark big-eared bat cave is equipped with an alarm. She said the alarm was in place before the disease was discovered because there are only about 1,200 big-earedbats left worldwide.
Scott said signs posted on trails explain why the caves will be closed indefinitely and so far there hasn’t been any impact on visitation.
Last week, the U.S. Geological Survey National Wildlife Health Center released the findings of a study confirming the Geomyces destructans fungus causes white-nose syndrome. The first documented case of white-nose syndrome in the U.S. was found in February 2006, about 40 miles west of Albany, N.Y.
More than 1.25 million bats have died from the disease since its discovery but the true number is assumed to be much higher, said Jeremy Coleman, the services’ national white-nose syndromecoordinator.
All along, researchers have been working under the assumption the fungus was causing the disease, but having scientific confirmation will help move the overallinvestigation forward, Coleman said.
“It’s a big hurdle because we have to demonstrate the cause to really work on solutions,” he said.
INVESTIGATIVE STEPS
The fungus has long been thought to cause the disease, but it had to be scientifically proven to build a strong foundation for further research, said David Blehert, a U.S. Geological Survey microbiologist and an author of the study.
Blehert said biologists from several agencies and universities in Tennessee, Pennsylvania and Wisconsin worked on the project, which involved placing drops of a solution made from Geomyces destrucants spores on the wings of captive small brown bats. He said 100 percent of the bats that had spores placed on them developed white-nose syndrome, thereby proving the fungusis the cause and that it can be spread by bats as well as humans.
It’s similar to the common cold, in that a sick person can spread germs by sneezing or shaking hands, Blehert said. In fact, he said many researchers believe the fungus was transported into the U.S. by a someone who had been in caves in Europe, he said.
Blehert said the syndrome was first spotted in a cave attached to New York’s Howe Caverns, which sees about 250,000 visitors a year. He said the first documented case was not in the tourist section of Howe Caverns, but the large number of visitors makes the concept of human introduction plausible.
In the course of researching the cause of the disease, researchers developed methods that will be used to test possible disease management techniques, Blehert said. He said to conduct the research, scientists had to develop a system for maintaining hibernating bats in a lab.
Blehert said they developed a caging system that uses incubators.
“It’s not quite as realistic as an artificial cave, but it meets biological standards and is humane,” he said.
Coleman said work is under way to create a better means of identifying the presence of the fungus.
Because white-nose syndrome is affecting such a large number of bats it is considered an epizooitic, which is the animal equivalent of an epidemic, Coleman said.
Until now, researchers have relied on the presence of sick bats to determine the fungus is in a cave, Coleman said. If the fungus is in a cave, but bats are not, he said, it could be spread by people or transient bats.
Coleman said he prefers people stay out of caves, but if they go in they need to decontaminate their equipment. He said there is no way to stop bats from spreading the disease, but people don’t need to help.
“For the immediate future, we need to make it no worse than what the bats do themselves,” Coleman said.
STAY OUT
Most public caves in Arkansas are closed, but the vast majority are on private property, said Blake Sasse, nongame mammal biologist for the Arkansas Game and Fish Commission.
Sasse said there are 3,500 documented caves in the state, though most don’t have significant bat populations. He estimates at least 600 caves are closed statewide, though the most well-known remains open for tours.
Blanchard Springs Caverns, which is operated by the U.S. Forest Service, remains open to guided tours, Sasse said. Visitors are required to go through decontamination procedures before and after the tours, he said, and are not allowed to use items that may have been in contaminated caves.
Sasse said though most of the caves are on private property, landowners tend to restrict access to caves on their property anyway, and are often receptive to putting up gates.
So far there have not been any confirmed cases of whitenose syndrome in the state,Sasse said, but there have been in Tennessee and Kentucky. There also have been suspected cases of white-nose syndrome in Missouri and Oklahoma, he said.
Sasse said the state is home to 16 bat species, of which three are endangered: the Indiana bat, Ozark bigeared bat and gray bat, all of which are found in the Ozarks. It’s difficult to estimate the number of bats in the state, he said, because many hibernate here but summer in other states.
There are only about 500 Ozark big-eared bats in the state, Sasse said, and that particular species can only be found in Arkansas and Oklahoma. There are probably about 2,000 Indiana bats in the state, he said, and about 500,000 gray bats hibernate here.
Sasse said there are only about 100,000 gray bats that live in maternity colonies in Arkansas during the summer. He said that even though some bats can live 30 years, they only have one offspring a year so it is hard for them to recover from disasters.
White-nose syndrome iseven more threatening because it affects the young as well, Sasse said. He said in some places the disease has killed at least 90 percent of the bat population, which could be especially devastating to the endangered bats.
The Boxley Bat Cave along the Buffalo National River is one favored by hibernating Gray bats, said Chuck Bitting, geologist for the Buffalo National River.
Bitting said during winter the Boxley cave, which is also known as the Cave Mountain cave in Newton County, has more than 300,000 Gray hibernating bats. It is also among hundreds that are closed to the public, he said.
There are a handful of caves in the park that remain open, Bitting said. He said the caves at Lost Valley Trail and some along Buffalo Point are open because there isn’t a practical way to close them off.
Bitting said while some caves are posted as closed, Boxley Bat Cave is fenced.
Sasse said the Gray bat had recovered well enough over 20 years that it was about to be removed from the endangered species list, but it was left on after the discovery of white-nose syndrome. He said there aren’t many caves that have populations of Gray bats as large as Boxley Bat Cave.
Winter is the only time researchers can actively monitor the disease because it appears to only attack the bats while they hibernate, Sasse said, so teams are preparing to survey 75-100 caves.
Bitting said researchers can’t conduct as many surveys as they used to because it takes so long to disinfect equipment before entering each cave.
“For now all we’re doing is buying time until we figure out if there is some way to eliminate the fungus or we can some how treat the bats,” Bitting said.
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Northwest Arkansas, Pages 7 on 11/07/2011