Study: Fungal disease killing over 90% of 3 bat species in Pa., elsewhere

Southwestern Pennsylvania bats were part of a new large national study that flagged a die-off nationally of more than 90% of certain bats in less than 10 years.

The bats in question are the northern long-eared, little brown and tri-colored bats. Researchers also found declines in Indiana bat and big brown bat populations.

All of those bat species are found in Pennsylvania.

The study was published in Conservation Biology.

The bats were killed by white-nosed syndrome, which is caused by a fungus that grows in cold, damp and dark places frequented by hibernating bats in the winter. The fungus grows on the skin of bats, causing them to wake up in the winter, resulting in dehydration, starvation and often death, according to WhiteNoseSyndrome.org.

“The severity of the impact of this disease on bat populations is staggering,” said Winifred Frick, chief scientist of Bat Conservation International, one of the paper’s authors.

“We found that nine out of 10 bats of the most vulnerable species are now gone,” he said.

“Bats are essential to our ecosystems, and our results that stem from working with so many biologists across the United States and Canada focus our efforts on how best to protect these important mammals.”

The Pennsylvania Game Commission’s Non-Game Mammal Section Supervisor Greg Turner, who is a co-author of the new paper, conducted bat surveys for the study throughout the state including locations in Westmoreland, Armstrong, Butler, Beaver, Cambria, Fayette, Somerset, Bedford, and Huntingdon counties and elsewhere in the state.

The large national study drew on the most comprehensive data set on North American bat populations to date, which includes data from over 200 locations in 27 states and two Canadian provinces. The study included research conducted over 23 years.

Turner was among the first group of biologists to work on tracking the deadly bat disease since it was detected in New York in 2006. Turner started to survey bats for the disease to understand its prevalence in Pennsylvania and published his research.

“At that time, we didn’t know if it was a problem that was localized or a new disease,” he said.

“It’s a big thing now that the spread has gone from five and six states,” he said. White-nose syndrome has since spread to 35 states and seven Canadian provinces,.

It has been confirmed in 12 North American bat species.

The study demonstrates the depth of devastation of the white-nose syndrome “so people have a grasp of how serious the problem is,” he said.

Pennsylvania is home to nine bat species, six that hibernate and three that migrate. All six species that hibernate get the white-nose syndrome — four of those species are “decimated with population declines in excess of 95% here,” Turner said.

Mortality rates vary by species, region and hibernation location, he said. For example, little brown bats in New York declined by 91% but declined by 99% in Pennsylvania, he said.

Among the caves Turner and researchers visited was one in Butler County where they found a population of about 100,000 bats hibernating around 2006. Then in 2011, Turner and his crew re-surveyed the Butler cave and found only 40 bats.

The loss of the bats will impact the ecosystem as they eat bugs — lots of bugs. A single bat consumes 900,000 to 1 million insects a year, Turner said.

“If you lose a couple million bats, which we did in Pennsylvania, hundreds of millions of insects were not consumed,” he said.

The implications of losing a predator that eats that many insects are not yet known, but could potentially cause a greater spread of diseases carried by mosquitoes and more agricultural crop damage by insects, Turner said.

Currently, Turner has found “a little” stabilization of bat populations affected by the disease.

“There’s a lot of movement of the survivors on the landscape now,” he said.

Jeremy Coleman, national white-nose syndrome coordinator for the U.S. Fish and Wildlife Service and an author of the paper said there is hope.

“Through strong collaborative efforts like this analysis, we continue to learn more about the dynamics of this disease. And we will build the infrastructure we need to conserve native bats for future generations.”

For more information about white-nose syndrome, visit whitenosesyndrome.org.