June 5, 2009

Mysterious Fungus Is Decimating US Bat Populations

Experts warned Congress on Thursday that a mysterious fungus attacking America's bats represents the most serious threat to wildlife in a century and could spread nationwide within years.

The condition, known as white-nose syndrome, gets its name from the white fungus speckled amongst the bats, reports the Associated Press.

Experts told two House subcommittees on Thursday about discovering caves where bats had been decimated by the disease.

"One cave there was turned into a morgue, with bats freezing to death outside and so many carcasses littering the cave's floor the stench was too strong for researchers to enter," said one state wildlife biologist from Vermont.

Bat experts warned that the fungus could strike caves and mines with some of the largest and most endangered populations of hibernating bats in the United States if nothing more is done to stop its spread.

So far the six species of bats that have been stricken by the fungus can eat up to their body weight in insects a night, reducing insects that destroy crops, forests and carry disease such as West Nile Virus.

Thomas Kunz, director of the Center for Ecology and Conservation Biology at Boston University, said that between $10 million and $17 million is needed to launch a national research program into the fungus

"We are witnessing one of the most precipitous declines of wildlife in North America," he said.

White-nose syndrome is probably the most serious threat to wildlife in the past century, according to Merlin Tuttle, a world-renowned bat expert and president of Bat Conservation International in Austin, Texas.

He also called for more research to determine its cause and how it was being spread.

Tuttle told the panel he never dreamed anything could pose this serious a threat to America's bats.

"This is the most alarming event in the lifetime of a person who has devoted his life to recovering these populations," he added.

White-nose syndrome has spread to 65 caves in nine states since it was first discovered in a cave west of Albany, N.Y., in March 2007.

Federal wildlife officials said it even turned up last winter in West Virginia and Virginia. There are also several caves suspected of harboring the fungus in Canada.

The condition has caused the deaths of between 500,000 to 1 million common species bats, and wildlife officials say the fungus looks to be on the verge of entering the Southeast and Midwest, where some of the most endangered and largest populations of bats live.

The fungus is known to occur in caves used by the Virginia big-eared bat, which has a population of only 20,000.

Marvin Moriarty, acting deputy director of the Fish and Wildlife Service, said there are likely to be some serious bat issues if it spreads any further.

"If it makes that jump, we have a real problem."

While there is no evidence that people can be harmed by the fungus, they may be contributing to its spread. The Interior Department and Forest Service have both closed caves to people on forest lands in 33 states and urged the public not to enter caves or abandoned mines in states with white-nose syndrome.

Some $5 million has already been spent researching the problem.

Del. Madeleine Z. Bordallo, D-Guam, said the severe mortality and sudden spread of white-nose syndrome demonstrates the need for a rapid response beyond closing caves where bats live.

She said the syndrome "could be an ecological and economic disaster if it remains unchecked."

Moriarty said one possible consequence of the syndrome's toll on bats is increased use of pesticides to control inspect populations.

He said the fungus attacks bats during winter hibernation when they are most vulnerable and their temperature is lowered so they can last through the winter on the fat they've put on by feasting on insects.

The fungus seems to thrive in cold temperatures and the densities of bats huddled on the ceilings and walls of cave likely help it to spread, according to research.

Experts say it is still unclear exactly how the fungus kills the bats, but they do know that once it attaches to them it invades tissues, causing the bats to burn up excess energy.

Most of the infected bats simply starve and die, while others perish after leaving the cave prematurely to look for nonexistent food in the winter.

Moriarty and his colleagues told the House panel they went into the Greeley mine in Vermont last spring where there were supposed to be 3,000 bats in the cave and they could only find 33.

"And I don't think a single bat was going to make it out of the cave," he said.


On the Net: