States work to save the last bats

By JUDY BERNSTEIN

Contributing writer

Five years after the first dead bats were found in a cave west of Albany, the disease known as white-nose syndrome has killed off most of the region’s hibernating bats.

The situation has gotten so dire that wildlife officials in Vermont and New Hampshire are now considering rounding up whatever surviving bats they can find and allowing them to spend the winter in abandoned military bunkers where the climate can be controlled.

In the meantime, state wildlife experts are urging homeowners to let them know if they find any bats in attics this spring and summer – and to avoid at all costs killing or chasing away the winged creatures.

“Now that we really are down to ‘last bat standing,’ each individual bat’s become more important,” said Ann Froschauer, a bat expert with the U.S. Fish and Wildlife Service. The federal agency announced in late May a plan to make it easier for the dozens of groups and individuals nationwide to work together to try to stop the spread of the disease. The plan will facilitate communication between more than 100 federal and state agencies, research institutions, universities, organizations and individuals trying to get to the bottom of the mysterious illness, Froschauer said.

White-nose syndrome is now affecting bats in four Canadian provinces and in 19 states stretching from Maine to North Carolina and as far west as Indiana. Five new states joined the list this spring.

The loss of “well over a million” bats is considered North America’s “most precipitous wildlife decline in the past century,” said Nina Fascione, executive director of Bat Conservation International, in testimony to a congressional subcommittee in April.

Experts are warning that the massive die-off of bats will likely have economic and environmental consequences, given that bats normally eat large numbers of insects considered crop and forest pests. This concern is particularly strong as the disease spreads major agricultural states in the Midwest and Great Plains.

An analysis in Science magazine in April concluded that failing to save bats could mean damaged crops and the need to use more pesticides, costing the agriculture industry at least $3.7 billion per year -- and possibly many times that.

In some areas of the country, such as Texas, which was a focus of the article, bats eat insects that target corn and cotton. The females in particular eat so many insects in early summer while pregnant that they can actually delay farmers’ application of expensive pesticides by one or two applications.

The report’s authors extrapolated their findings to the rest of the country to get their estimate of the possible cost of the loss of the bats.

Tracking the cause

White-nose syndrome got its name from the white fungus that can be seen on the muzzle and wings of infected bats.

Identified as Geomyces destructans, it is a cold-loving fungus also found in northern Europe. Experts said it is not killing bats there, perhaps because the bats and fungus evolved at the same time, allowing those bats to adapt and build resistance to it. The latest research reported at a national conference in May showed that the fungus is the cause of the disease and that it was brought over from northern Europe or western Asia, most likely by a bat in a transport carton, to New York state.

The fungus spreads between bats huddling together in caves and mines during their winter hibernation. All of the nation’s 25 hibernating species are considered at risk. Infected bats wake up repeatedly during hibernation, which causes them to burn up the fat reserves they need to survive the winter. They often emerge early from hibernation, before their food supply of insects is available, and freeze or starve to death.

So far, bats in the Northeast have been the hardest hit. In New York and Vermont, where white-nose syndrome was first identified, nearly 90 percent of hibernating bat species have been killed off, said Scott Darling, a biologist at the Vermont Fish & Wildlife Service.

Darling said his agency is in the process of listing several of the species affected by the disease as endangered, as Massachusetts and some other states are also doing. “In Vermont, we’re really in the mode of trying to conserve what’s left and buy us some time to keep some of these animals alive until a treatment’s available,” Darling said. Fungicides have been found to kill the fungus in laboratory petri dishes, but treating bats in their caves ends up disrupting their hibernation and leads to as many deaths as the disease does, he said.

So he said Vermont wildlife officials are also looking at “radical or creative” ways to keep the bats from dying in caves and mines in the next hibernation season. One idea involves the possibility of moving bats into abandoned military bunkers for the winter hibernation, allowing the bats to live in a fungus-free environment where researchers could control temperature and humidity.

Consequences unknown

In New York, the toll of the disease can be seen by the loss of nearly all of the state’s little brown bats, a half-million of them. They used to make up most of New York’s hibernating bat population, said Carl Herzog, a wildlife biologist at the state Department of Environmental Conservation.

The Indiana bat, already listed as endangered, showed a significant decline in a recent survey, as did others.

“In general, you have to say the decline continues,” Herzog said. Herzog said he hopes some behavioral changes or immune system adaptations will save the bats. But he said there’s no way of knowing how soon that might occur. Sometimes diseases wipe out an entire population.

Meanwhile, he said, there’s also no telling what the loss of bats could mean to the environment.

They eat some mosquitoes, but they eat more moths and beetles, which could affect local trees and crops. But Herzog said no studies have been done in the Northeast to show cause and effect the way the Texas studies cited in the Science article did.

Fascione, of Bat Conservation International, said in her congressional testimony that, in addition to eating vast numbers of insects, bats also pollinate crops and disperse seeds.

Bat droppings in caves also support unique ecosystems, including microorganisms that could provide the resources for detoxifying industrial wastes and producing safer pesticides and antibiotics, she said.

“Bats are vital to our ecosystem, and they’re vital to our economy,” Fascione said in an interview. “If there’s any kind of silver lining or bright side to white-nose syndrome, it is that people are now learning about bats and caring about bats.”

Herzog said he tells people they should be concerned about the loss of any species, because the web of interactions between all the living things in the biosphere is complicated.

“It’s more than complicated; it’s chaotic in a way that we may not be able to understand,” he explained. That should be cause for concern when you start messing with that, intentionally or unintentionally. We don’t know what the ramifications could be.”