A deadly fungal disease that infects northern long-eared bats has caused such a sharp decline in their numbers that the United States Fish and Wildlife Service (USFWS) declared the species endangered this week.
The disease, called white-nose syndrome, is caused by the fungus Pseudogymnoascus destructans, also called Pd. Pd attacks bats’ bare skin while they’re hibernating, forming a visible white fuzz on their snouts, ears and wings.
“This listing is an alarm bell and a call to action,” USFWS director Martha Williams says in a statement. “White-nose syndrome is decimating cave-dwelling bat species like the northern long-eared bat at unprecedented rates.”
The fungus was first documented in 2006, when explorers photographed bats with telltale white noses in a cave near Albany, New York. The disease has since spread to 12 bat species in at least 38 states and eight Canadian provinces, killing millions of the flying mammals across North America. At affected sites, white-nose syndrome has led to an estimated 97 to 100 percent decline of northern long-eared bats. The disease has spread to 80 percent of the species’ geographical range and will likely affect the bats’ entire territory by the end of the decade, per the USFWS.
Pd causes hibernating bats to wake up more frequently, leading them to burn up fat reserves and eventually starve. Even before they’re aroused from their slumber, sick bats use up energy twice as quickly as healthy ones do. Pd spreads from bat to bat through physical contact, but they can also pick it up on cave surfaces. Humans can accidentally spread the fungus from one area to another by tracking in spores on their clothes or shoes. Current evidence suggests humans are at extremely low risk for infection—the fungus only grows at temperatures much lower than the human body, and no cases of white-nose syndrome have ever been documented in humans exposed to infected bats, per the National Park Service.
In 2015, the Fish and Wildlife Service listed northern long-eared bats as threatened because of the disease.
“Bats are a critical component of our nation’s ecology and economy, maintaining a fragile insect predator-prey balance; we lose them at our peril,” Dan Ashe, former USFWS director, said in a 2015 statement. “Without bats, insect populations can rise dramatically with the potential for devastating losses for our crop farmers and foresters. The alternative to bats is greater pesticide use, which brings with it another set of ecological concerns.”
Annually, the pollination and pest control services that bats provide contribute at least $3 billion to the U.S. agriculture economy, per the USFWS statement. Efforts to help the species’ recovery will focus on forested areas where the bats roost in summer, writes John Flesher for the Associated Press (AP). The service also plans to work with wind companies to reduce fatalities from turbine strikes.
The bats’ endangered status takes effect on January 30, 2023.
“This species is in dire straits, but we never want to give up hope,” Winifred Frick, chief scientist with the nonprofit Bat Conservation International, tells the AP. “We can do amazing things when we work hard and have legal protections in place to protect these small colonies that are left.”