Bats Prove a Bellwether for a Changing Habitat Paradigm

When the northern long-eared bat was added to the federal endangered species list this spring, the implications for Long Island proved thorny.

These bats — along with several other species that are likely to be listed as endangered this year — have been suffering for several years now due to white nose syndrome, a fungal infection spread during the bats’ hibernation in caves.

But Long Island long-eared bats, lacking caves to hibernate in large numbers, have proved to be resilient against the fungus, and this is one of the few places they’ve been found to be thriving.

This adaptation has been a boon for bats, but it has created new conundrums for ecologists working to restore forest health, and for developers looking to build in areas where the bats are now living.

The Central Pine Barrens Commission, which for years has been working on plans to burn sections of this fire-dependent ecosystem to reduce fuel loads, manage pests like the southern pine beetle and create a healthy habitat for woodland creatures, just began to be able to hire a seasonal prescribed fire crew last year, with the help of $1.25 million in funding from the New York State Department of Environmental Conservation.

In 2022, they were able to burn 57 acres of woodlands and 315 acres of grasslands, said Polly Weigand, the Science and Stewardship Manager of the Central Pine Barrens Commission, who has been working on the Commission’s prescribed burn program.

This spring, their work proved tricky, as they navigated the new federal restrictions imposed by the bats’ endangered status, which went into effect March 31. Prescribed burns already have to adhere to strict seasonal and weather-related guidelines, and are usually conducted in woodlands here mostly in the months of April and May, just when northern long eared bat pups are being born, and before they are able to fly.

“To burn under the new regulations, you have to have habitat management plans to move forward,” said Ms. Weigand this spring. “Some of the mitigations are already being implemented. Bats go into a state of torpor overnight, so we wait to start ignition until they’re awake. But this gets tricky during their pupping period. The pups can’t fly in that time frame. We hope we may be able to resume in mid-August.”

The CPB prescribed burn crew was able to get some work done this spring, burning grasslands at the Otis Pike preserve in Manorville and in DEC grasslands in Rocky Point, and woodland burn areas at Brookhaven National Laboratory, which had already been researching bat populations at the lab and had habitat management plans in place.

“The northern long eared bats here are considered a source population to repopulate the mainland,” said Ms. Weigand, adding that bats find it easier to forage in open areas that have been cleared by prescribed fire. “The management we’re doing is improving their habitat.”

Bats here serve a vital ecological function by eating pest insects that would otherwise eat crops.

BNL Prescribed Fire Program Manager and ecologist Kathy Schwager said the lab has been surveying on-site bat populations for several years, and was able to share that data with the Fish and Wildlife Service in order to get the go-ahead for this spring’s prescribed burns there. They’ve also worked to protect snag trees and trees with cavities in them, which are found to be nesting spots for Long Island bats.

Ms. Schwager said finding the exact right conditions for prescribed burns is always a challenge, on a day this spring that proved a perfect example, as the fire crew comprised of the Central Pine Barrens Commission’s crew, BNL’s professional firefighters and local volunteer firefighters gathered at the lab. By the time they were ready to get in the woods to work, the relative humidity had plummeted to the point where the burn had to be called off, which is known in wildland fire terms as “going out of prescription.”

“There are a lot of moving parts here,” she said. “We tend to learn as we go. Fire hasn’t been part of the ecosystem in recent years, and was we’re doing is adaptive management. Especially with climate change, what was appropriate 1,500 years ago king not be the right thing now.”

Researchers from SUNY Albany have been studying Long Island bat populations for several years, in the hopes of finding clues to help the bats become more resilient. 

They’ve found the bats on Eastern Long Island, on Nantucket and on Martha’s Vineyard, where they seem to hibernate in crawl spaces below people’s houses, with only five or six other bats, instead of in groups of hundreds, where the fungus can easily be transmitted from one bat to the next. They are also more likely to find insects to feed on during Long Island winters if they awaken during hibernation.

White Nose Syndrome was first identified among bats in a cave in Schoharie County, NY in 2006, and has rapidly spread throughout the country. It also affects other species of bats that are found on Long Island, including the tri-colored bat and the little brown bat, both of which are proposed to be added to the U.S. Fish & Wildlife Service’s Endangered Species list in September 2023.

“Since the Long Island sub-population (of northern long eared bats) is the most robust remaining in the entire state, and may constitute the only hope for continued presence of this species in New York State, projects on Long Island will be evaluated differently by both DEC and the FWS, and we are working together towards developing this region-specific guidance,” according to a DEC spokesperson.

The North Fork Audubon Society has also been exploring the presence of the northern long-eared bat at the Mill Road Preserve in Mattituck, adjacent to a proposed excavation project for yacht storage buildings at Strong’s Yacht Center.

After reading in the Draft Environmental Impact Statement for the project that there are likely to be northern long-eared bats and three other bat species in the woods, and hearing from a neighbor of the property who had seen bats swooping into his swimming pool to drink, North Fork Audubon board member Theresa Dilworth decided to learn more.

She has been visiting the Mill Road Preserve after dusk this spring with an Echo Meter, a device made by Wildlife Acoustics that attaches to a smartphone and can be used to detect bats.

Over the course of 10 evenings, she detected all nine species of bats known to live in New York State, including 32 instances of calls from northern long-eared bats, 25 from tri-colored bats and and 93 from little brown bats.

“The Audubon Society has been in touch with a bat biologist at the New York Department of Environmental Conservation and with Dr. Kristjan Mets, a bat specialist with a doctorate in biology and ecology from Stony Brook,” said Ms. Dilworth in an announcement of her work. “Recognizing that the devices are not infallible, the next step is to get the New York Department of Environmental Conservation to confirm the findings using their own equipment, and to have the recordings already taken analyzed in more detail by bat biologists.”

According to a DEC spokesperson, the DEC is aware of the Audubon surveys but did not partner with the group or conduct the surveys.  

“DEC has had an acoustic detection that encompasses the project site, and is already considering it occupied with a summer detection,” the spokesperson added. “Unless a northern long eared bat roost tree was found on site or a hibernacula on site, the acoustic detections from this survey would not change the DEC guidance for protection. The project is following guidance and would avoid impacts by doing clearing in the winter.”

The DEC recommends that property owners leave snag and cavity trees standing during the seasons in which the bats might be present, and only removing trees during their hibernation period, which in Suffolk County is believed to be between Dec. 1 and Feb. 28, “unless their removal is necessary for protection of human life and property.” and to contact the DEC if bats are observed flying from the trees. More info is at www.dec.ny.gov/animals/106713.html.