Mysterious disease still killing bats
By KATHRYN FLAGG
ALBANY, N.Y. — The first time he stepped into a cave hit by what scientists have dubbed white nose syndrome (WNS), Peter Youngbaer was startled — and horrified. Almost all of the bats in the hibernation colony had died.
“There were hundreds and hundreds of carcasses littering the floor,” Youngbaer, president of the Vermont Cavers’ Association and an avid caver himself, said. “We didn’t know if it was an isolated incident. You started seeing it in other places — and then the white noses, the fungus, became this evident sign.”
Youngbaer joined between 80 and 90 other scientists, wildlife specialists and conservationists in Albany, N.Y., last week to discuss the mysterious syndrome behind these die-offs, which have escalated from just two incidents in caves in New York a year ago to documented mortalities at caves and mines in New York, Vermont, Massachusetts and Connecticut, with suspected sites in Pennsylvania.
The syndrome is estimated to have killed hundreds of thousands of bats this year. Last week’s conference brought together individuals from two countries and over 25 organizations to identify the most urgent research questions for the scientists and management agencies struggling to unravel the causes fueling the unprecedented bat mortalities.
Scientists at the meeting identified starvation and dehydration, direct mortality from pathogens, the effects of environmental contaminants or multi-factoral causation as the most promising hypotheses driving the mortalities — but the meeting called into sharp perspective the long road that faces specialists investigating the syndrome.
“I think that we now have a focus that we can test,” said Scott Darling, a wildlife biologist for the Vermont Fish and Wildlife Department. “I can only hope that the answer lies somewhere in one of those four hypotheses.
“If it does,” he continued, “we will make headway this year. I’m pretty confident on that.”
Conference participants also drafted plans for collection and contamination protocols, field diagnostics, summer data collection surveys, maternity colony assessments and communication plans, among other priorities, to tackle WNS in the coming months.
“Through this last winter, we thought this was strictly a winter issue,” said Darling. He and many others close to the issue hoped that the bats that survived the winter, when they came out of hibernation this spring, would regain their strength. Reports so far, however, are grim.
“We continue to get reports of dead and dying bats throughout much of the state,” he said. “It’s clear that the animals are still dying out there.”
Biologists cannot accurately estimate the number of bats which died last winter until the bats settle in for hibernation next fall, but rough estimates currently put the number of dead animals between 500,000 and 600,000 bats. The syndrome has a mortality rate of upwards of 90 percent.
The months ahead will be busy ones for Darling and others at work on this puzzling phenomenon.
“It seems that across the range where WNS has been confirmed, bats are being observed with scaly skin on their forearms and wings. A lot of scar tissue is showing up on their wings, and some of their wings are even torn,” he said. “We’ll be doing some surveys this summer just to see if we can observe this.”
He also said that documenting the condition of the bats when they enter into hibernation will be a critical task in the next few months. All of the animals that have died showed signs of starvation, but scientists do not yet know whether or not the animals are entering into hibernation with enough fat stored for the winter.
Though the atmosphere at the end of the conference was not optimistic, Darling said, a sense of accomplishment and renewed purpose marked the occasion.
“It’s not easy to get 80, 90 people in a room and agree on a strategy,” he said, “but we did that.”
Youngbaer, who also serves as the liaison on WNS to the National Speleological Society and the vice president of the Northeastern Cave Conservancy (NCC), which closed its New York caves after an emergency meeting last winter, agreed that the meeting was a remarkable step for the many individuals investigating the syndrome.
“It was the first time that all of the people working on this … were all together in the same room,” said Youngbaer. “I don’t think you can overestimate the value of actually physically being together and being able to converse.”
Because no baseline research exists yet, said Darling, it is difficult to speak conclusively about the immediate effect these mysterious deaths will have on the ecosystem, including the summer insect population.
“There are anecdotal reports coming in,” said Darling, but he stressed that it is difficult to isolate the roles bats play in “all of that.”
“I can tell you that when do you the math for losing 500,000 bats,” said Darling, “we’re looking at 2 billion insects a night” that would have been consumed.
In Vermont, affected caves have been documented in Rutland, Bennington and Orange counties, as well as nearby Essex and Warren counties in New York — though Addison County could be impacted as well.
“The distribution of sites that are affected does raise the real possibility that there are sites in Addison County that are affected,” Darling said.
Last week’s conference included a briefing from experts at work on Colony Collapse Disorder (CCD) in bees, a similarly mysterious malady responsible for the disappearance of pollinators. Though Darling stressed that bees and bats are very different animals, he noted the parallels are “a bit scary.”
More importantly, he said, the study of CCD has important implications for the way scientists — and a vast array of state, federal and university organizations — approach the research.
“Communication is key,” he said. “We don’t want to waste resources.”
Darling also noted that the cases of both the bee and bat mortalities points to the necessity of monitoring weakened populations in local ecosystems — a system not unlike the highway infrastructure, he said.
“You have to pay attention to the potholes and the cracks in the bridges,” Darling said. “I view these … as cracks in our ecological infrastructure that we need to pay attention to.”