Good news for bats

Little brown bats were once the most widespread .bat species in New York State, but its population has declined about 90 percent since the discovery of white-nose syndrome in a cave south of Albany several years ago.

Little brown bats in hibernation. Photo by Larry Master.

Now there may be a bit of good news: the latest survey of caves in the Albany region detected an increase .in the number of little browns.

“While we remain cautiously optimistic of encouraging trends for some species seen more recently, it will likely take several years before we fully know how to interpret this,” said Kathleen Moser, assistant commissioner of natural resources for the state Department of Environmental Conservation. 

DEC’s full news release follows.

DEC REPORTS: 2012 WINTER BAT SURVEY RESULTS

The results of the winter survey of hibernating bats in New York are now available, the New York State Department of Environmental Conservation (DEC) announced today.  This survey was a cooperative effort among state wildlife officials, the U.S. Fish and Wildlife Service and numerous volunteers to monitor the effects of white-nose disease, a fungal infection that has devastated regional bat populations since it was first documented in New York in 2006.

The most encouraging observations came from surveys of the five hibernation caves in the greater Albany area where the disease was first discovered. Previous reports have suggested that little brown bat counts at these sites seem to be stabilizing in recent years. This year’s surveys saw substantial increases in little brown bats at three out of five of these caves. The largest and best documented of these sites saw an increase from 1,496 little brown bats in 2011 to 2,402 this year.  It is premature to conclude that population recovery is underway for this species, however, because of the small number of hibernation sites that have experienced increases and the fact that alternate explanations are plausible.  Bats are highly social animals and observed increases could be the result of consolidation of individuals from other hibernation sites, for example.

“While we remain cautiously optimistic of encouraging trends for some species seen more recently, it will likely take several years before we fully know how to interpret this,” said Kathleen Moser, DEC’s Assistant Commissioner of Natural Resources.  “DEC is assisting in national bat research and with those seeking solutions to the effects of the white nose disease.  As a preventative measure we can take now, we encourage the public who enter caves recreationally, to refrain from entering hibernation sites while bats are there.”

Based on this year’s survey, total observed declines in population attributed to the disease for tri-colored bats have been revised upward.  Prior to the arrival of white-nose disease in 2007, a total of 2,285 tri-colored bats were counted at 37 representative hibernation sites in the state.  Since that time, a total of 112 bats were observed during surveys of those same sites, suggesting a statewide decline of 95 percent for the species. Northern long-eared bats have also been affected with a 98 percent observed decline (18 individuals observed in 36 sites compared to a pre-disease total of 911 bats at the same sites).  Although neither bat was considered a threatened species prior to the arrival of white-nose disease, both species are now extremely rare in New York.

No surveys were performed this year for the federal and state endangered Indiana bat. Previous surveys indicate that losses for this species have totaled 71 percent statewide (15,650 individuals remaining, down from a high of 54,689).  The population status of Indiana bats in New York will be reassessed in 2013.

Records of small-footed bats, a rare species even prior to the disease, show only a relatively small decline of 13 percent.  This species is difficult to count due to its secretive habits when hibernating, but focused survey efforts this season have bolstered previous observations that the impact of the disease is far less severe for small-footed’s than for most other hibernating bats.

Prior to the arrival of white-nose disease, the little brown bat was the most common bat species in New York State and has been observed hibernating in more than 100 caves and mines here.  Statewide losses for the species attributed to white-nose disease remain at approximately 90 percent. For more information on white nose syndrome in New York, visit the DEC website at http://www.dec.ny.gov/animals/45088.html.

Scientists pin down cause of bat disease

Researchers analyze the air near a hibernating bat in the Adirondacks. Photo by Carl Heilman II.

A study published in the journal Nature confirms that the disease decimating bat colonies in New York and many other states is caused by a fungus known as Geomyces destructans.

Known as white-nose syndrome, the disease causes lesions on the bats’ skin and a white growth on their muzzles. Since its discovery in a cave near Albany in 2006, it has spread to sixteen states and four Canadian provinces.

The disease has so devastated bat populations that some species are in danger of extinction.

Earlier this year, Winnie Yu reported in the Explorer that the number of little brown bats in the Adirondacks—once the most common bat in the region—has plummeted 90 percent. Northern bats are down 98 percent. Indiana bats, an endangered species, are down 60 percent.

Biologist Jeremy Coleman of the U.S. Fish and Wildlife Service, one of the five authors of the study, said today that the disease is continuing to spread, though there is some evidence that it has stabilized in some colonies.

Scientists had suspected that Geomyces destructans was the cause of white-nose syndrome, but the new study confirms it. Researchers at the National Wildlife Health Center in Wisconsin found that healthy bats exposed to the fungus developed lesions and other symptoms associated with the disease. Before the study, some experts speculated that the fungus was itself a symptom, not a cause, of illness.

The researchers say little can be done to control the spread of white-nose syndrome. One possibility is manipulating the habitats of caves to make them less hospitable to the fungus.

The same fungus exists in Europe, but it has not decimated bat populations there. It’s thought that the fungus may have been inadvertently carried to the United States by a human and introduced to a commercial cave in Schoharie County, whence it spread to bat hibernacula.

Coleman’s co-authors included three scientists from the U.S. Geological Survey: microbiologist David Blehert, wildlife pathologist Carol Meteyer, and wildlife disease specialist Anne Ballmann. The fifth researcher was Justin Boyles of the University of Tennessee.

For more information about white-nose syndrome and its impact on the Adirondacks, we encourage you to read Winnie’s story.

Bat die-off continues

White-nose syndrome, the disease decimating bat populations in the Northeast and beyond, is believed to have spread to all known bat caves in New York, according to the state Department of Environmental Conservation.

The fungal disease has reduced the populations of some bat species in the state by 90 percent since it was first documented in 2008.

Bat with white-nose syndrome. Photo by Larry Master.

The Graphite Mine in Hague, once the largest hibernaculum in the state, has been especially hard hit. The number of little brown bats has fallen from 185,000 to 2,000, DEC says. Two other species, the northern bat and the endangered Indiana bat, have disappeared from the mine entirely. Another, the tri-colored bat, has been reduced to a lone specimen.

DEC surveyed hibernacula early this year. “Caves and mines that avoided infection in the early years of the disease, perhaps by chance, are now infected,” acting DEC Commissioner Peter Iwanowicz said in a news release. “This year’s survey included hibernation sites that had not been visited by DEC in decades. What we found was disturbing. We now have sampled sites that represent the full range of environmental conditions across the state—and none have been spared. It is likely the sites not yet inspected are infected as well.”

But the populations held steady in two caves in the Capital Region, albeit at at roughly 10 percent of their pre-disease count. “Infected animals were present at these two sites, so it’s too early to say the decline here has halted,” said DEC bat biologist Carl Herzog, “but these two caves represent the most hopeful results in an otherwise negative report.”

DEC is working with the U.S. Fish and Wildlife Service to find ways to treat the disease and check its spread.

Click here to learn more about white-nose syndrome.

Our vanishing bats

Over the past four years, the number of endangered Indiana bats in New York State has plummeted about 50 percent. And that’s the good news.

The populations of other bat species in the state have fallen as much as 90 percent.

State biologist Al Hicks told the Adirondack Park Agency on Thursday that three species—the little brown, northern, and eastern pipistrelle bats—could be extirpated in the Northeast within a few decades.

A little brown bat with white-nose syndrome. Photo by Larry Master.

“Extinctions are not out of the question here,” Hicks said.

The bats are dying from white-nose syndrome. The disease’s name comes from the white fungus that appears on the animals’ snouts and wings. Infected bats often use up their fat reserves during hibernation and die of starvation. Many will leave caves in winter in a desperate search for food, but the insects they depend on for survival cannot be found at that time of year.

White-nose syndrome was first documented in 2008, when state scientists found thousands of dead bats in a cave south of Albany. They now think the disease originated in Howe Caverns, a commercial cave in Schoharie County. Photos taken at the cave in 2006 showed bats with the white fungus. In recent years, the disease has spread throughout New England, as far south as Kentucky, and as far west as Missouri.

Before the onslaught of white-nose syndrome, New York boasted the country’s third-largest population of Indiana bats, which are on the federal list of endangered species. Hicks put the population at 54,000. This paled in comparison to the number of little brown bats, the most common of the state’s bat species. One cave in the Adirondacks once harbored 200,000 little browns each winter. The Indiana bat, however, seems to be more resistant to the disease.

“There is a chance that the Indiana bat will be the most common bat in New York State, not because it’s doing well, but because it’s not dying out as much,” Hicks said.

When white-nose syndrome was first discovered, Hicks sent out pictures of infected animals to bat scientists around the country. None had ever seen anything like it. However, European scientists had. Apparently, bats in Europe have been living with white-nose syndrome for years, but for some reason it is not as lethal there.

Hicks said it’s possible that European bats have developed a resistance to the disease. Over time, he said, the same could happen here. If not, the die-offs will likely continue.