Fungus kills off 90% of NJ bat population

Get news from the world where animals and oddities rule!

April 6, 2010 5:10:22 AM PDT
A fungus has killed off about 90 percent of the state's bat population, according to scientists who recently conducted a count of hibernating bats.

The devastation was shocking in the largest hibernation spot for bats in New Jersey - Morris County's Hibernia Mine. As many as 30,000 bats normally spend the winter, but a recent count found only about 1,700 alive - and many of those showed signs of infection, said Mick Valent, principal zoologist with the state's Endangered and Non-game Species Program.

"The results we had from Hibernia Mine were certainly not good news," Valent said.

The fungus, called white-nose syndrome for the whitish powder that appears on the nose, ears and wing membrane of infected bats, was first discovered on bats in New York in 2006. It has since been linked to the deaths of more than a million bats in 11 states, from New Hampshire to Virginia, and has also spread to Ontario, Canada. The virus appears to be following the path of the Appalachian Mountains.

"This is unprecedented and scary," said Lance Risley, a bat researcher and chairman of the biology department at William Paterson University. "This wave has killed more mammals in the United States than anything in recent memory. It is entirely possible it could sweep all the way across the country to California, killing millions more bats."

Experts warn that the widespread loss of bats has potential ramifications for humans, since bats consume huge quantities of bugs, including insects that damage crops or carry West Nile and other potentially fatal diseases.

The bat deaths come at a particularly bad time in New Jersey, where mosquito control experts worry that the recent rains and floods have created ample breeding grounds for mosquitoes that could result in an unusually large mosquito population. A single bat can consume more than 3,000 mosquitoes on a single summer night.

Last November, Congress approved $1.9 million for research to identify the cause and seek solutions for white-nose syndrome.

Biologists in affected states are discussing ways to help the decimated bat population recover. They are testing various fungicides, hoping to find one that might help bats recover without harming them.

New Jersey scientists, meanwhile, are considering capturing several dozen infected bats, nursing them back to health, then reintroducing them to a contaminated hibernation spot to see if they have developed immunity to the mysterious disease. Valent first saw signs of white-nose syndrome among bats in New Jersey in the winter of 2008-09.

The recent count confirmed his fears that it would decimate the population.

Officials say all six species of bats that hibernate in New Jersey - big brown, little brown, Indiana, northern long-eared, small-footed and tri-colored or eastern pipistrelle - have been affected by the fungus.

"If this keeps going, our bat populations will disappear," Valent said. "Once the population drops so dramatically, the genetic variability of the species goes down, and they are more susceptible to a variety of illnesses."

Scientists are under pressure to quickly find a way to save the remaining bats and stop the spreading to other states. "There's not a lot of evidence of any silver bullet that could work," said Jeremy Coleman, national white-nose syndrome coordinator with the U.S. Fish and Wildlife Service. "Part of the problem is we still don't know how the fungal infection leads to death."

The running hypothesis among scientists is that the fungus irritates hibernating bats in some way, making them act erratically. They will emerge from their winter sleep, move about their caves and sometimes even fly outside as if in search for food - but all the activity causes them to burn through their fat reserves so they are unable to survive the winter.

Another theory is that some unknown agent attacks and weakens the bats initially, and the fungus acts as an opportunist by attacking the weakened bats, Risley said. The fungus causes serious damage to the bats' wing membranes, which makes flying difficult, Risley said.

Valent said New Jersey experts are contemplating capturing several dozen infected bats from hibernation sites in New Jersey and Pennsylvania over the next month and taking them to a center where they would be fed, given fluids and nursed back to health.

"We're hoping that once we get their metabolism back up, their immune system could recover, and they might be able to fight off the fungus," Valent said.

Then, at hibernation time in the fall, those bats would be sent to a New Hampshire hibernation site whose population was wiped out by the fungus.

Scientists would conduct air studies to make sure the site, a former mine tunnel, still contains fungus spores.

If the rehabilitated bats survive the winter without illness, it could be a sign they have built immunity to the fungus, and rehabilitation of sick bats on a wider scale might be worthwhile, Valent said.

Meanwhile, other researchers, are experimenting with the ingredients of various fungicides to see if they might be useful to combat white-nose syndrome.

But even if researchers come up with something that kills the fungus, it could impact other plants and animals in a treated cave. In addition, it would require multiple applications to kill the fungus, and Coleman said it would be difficult to go into a hibernation cave to apply the fungicide to hundreds of thousands of bats.

Each foray into the cave would disrupt the bats from their hibernation, causing them to burn through fat reserves and creating the same dangerous scenario that the fungus causes.

The ideal situation would be to discover and culture a biological control agent that would be self-replicating and spread from bat-to-bat contact, a bacteria or fungus that would eat this other bad fungus," Coleman said.


Load Comments