Unfamiliar fungus threatens to wipe out bat population

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By Carey Shea, May 21, 2009

It began with a couple of photographs in the winter of 2005-2006. Bats were discovered dead on the floor of Howe Cave, New York’s largest natural cavern system, their noses, ears and wings covered in a strange white substance. Unbeknownst to anyone before that discovery, White Nose Syndrome, as it would later be called, was slowly attacking the bat populations throughout the state.

 

Those pictures were taken by cavers who had no idea of the importance of their find. One year later, in March of 2007 New York’s Chief of the Wildlife Diversity for the Fish and Wildlife Department, Alan Hicks, and his team made the first scientific documentation of the fungus.

 

“We had five infected sites before we knew we had anything and it was state-wide in a year,” said Hicks.

 

In just three years, WNS would spread from that single cavern in New York to eight states and kill more than half a million bats.

 

A fungus, WNS grows on many species of bats including the federally listed endangered species, the Indiana Bat. With fewer than 500,000 Indiana Bats left in existence, a threat like WNS is particularly dire. 

 

“It’s a rapidly spreading ailment with exceptionally high mortality rates,” said Scott Johnson, a non-game mammalogist for Indiana’s Department of Natural Resources. “From an Indiana perspective it’s at the doorstep of the highest population of Indiana Bats in the country.”

 

According to a press release issued at the beginning of May, as a precautionary response the DNR is shutting down caves, mines and other dwelling spots for bats from hikers and cavers. This step will slow the spread of the fungus by humans, but will do little to stop transmission by the bats themselves.

 

Andy King, a U.S. Fish and Wildlife Service biologist in Bloomington specializes in the study and maintenance of bat populations in the state. He said that up until recently, the Indiana Bat population had been growing.

 

“In 2007 Indiana had over 50% [of the Indiana Bat population]. New York had the distinction of having the fastest growing population and now the fastest declining,” he said.

 

That’s because New York was caught relatively off guard by the danger of this new fungus. Lab tests show that WNS is a psychophilic fungus, or one that grows fastest in cold climates. Early hypotheses state, however, that it could survive as far south as Florida. The bats also need to have lower body temperatures, achieved during hibernation, in order for the fungus to multiply.

 

“Had we known,” said Hicks, “we would have jumped in with both feet. Long-term, the only solution is finding a beast that kills the beast.”

 

Hicks is referring to the effort among many biologist to discover a biological control, such as a bacteria or insect that might eat the fungus but not harm the bats.

 

This course has been somewhat effective containing the invasive purple loosestrife plant that is choking out other species of plant across the country. In order to combat the plant, several plant eating insects have been released into the areas overgrown with purple loosestrife. Though their effectiveness is still unverified, this method has provided inspiration to bat conservationists.

 

According to Hicks, in order to find something to combat WNS, a similar fungus must be found elsewhere to be observed. Some scientists believe that there is the possibility that WNS is a foreign invasive species. There is a similar species of fungus that attaches itself to bats in parts of Europe, but bats don’t seem to be harmed by it. If this proves to be the same species, this link could be very useful.

 

As it is, little has been discovered over the past three years about how to stop WNS, and the threat is growing every day.

 

“There have been large, 350 mile jumps,” said Johnson. In fact, the disease jumped from caves in New York and Pennsylvania to Appalachian caves in Virginia and West Virginia.

 

With such daunting evidence, the DNR decided to close all caves on public lands, in the Hoosier National forest, and have recommended all privately owned caves be closed as well; however, there seems to be little optimism that this will stop WNS.

 

“The primary route of transmission is going to be bat to bat, but we can’t control that,” said King. “The only variable we can control is people.”

 

Since the jump to West Virginia was so sudden, it does point to the human variable as a source of transmission. Cavers are advised to decontaminate all of their equipment after outings because the fungus and may be able to lie dormant in clothes for long periods of time.

 

Efforts are being made to solve the problem. On June 10, 2008, Bat Conservation International, based out of Austin, Texas, hosted the first science strategy meeting in Albany, New York. There, more than 100 participants from 20 states and two Canadian provinces took part in the discussion on the threat facing the bats.

 

On May 27 they will be hosting another meeting in Austin to see if any progress has been made.

 

Hicks hopes to be present at this next meeting and is constantly emphasizing the importance of studying this threat.

 

“The whole issue with white nose syndrome is a national issue. [We are] moving with urgency and caution,” he said.

 

The main problems Hicks is facing are the same problems Johnson and King face as well – awareness of the problem and getting the public to care about the bats.

 

“Bats have gotten a bum rap,” said King. “They have incredibly important roles in the environment. They keep insect populations in check, especially crop-harming ones. Any time you take a predator out of a food web it has an effect on the ecological community.”

 

Indiana has been lucky so far, but it is a luck that many expect to run out soon. If a solution is not found soon, the Indiana Bat, as well as the many others being attacked, may face extinction. Though they are hidden both in day and night, the effect of losing such an important link in the ecosystem is certain to have visible effects.

 

For more information, or to find out how you can help stop the spread of WNS, visit Bat Conservation International at http://www.batcon.org/ or visit the National Speleological Society’s website at http://www.caves.org/WNS/.