WASHINGTON, D.C. – White-nose syndrome (WNS) has killed 90 percent of northern long-eared, little brown and tri-colored bat populations in fewer than 10 years, according to a new study published in Conservation Biology. Researchers also noted declines in Indiana and big brown bat populations.

The findings, detailed in “The scope and severity of white-nose syndrome on hibernating bats in North America,” underscore the devastating impacts of the deadly fungal disease. The research tapped into the most comprehensive data set on North American bat populations to date, which includes information from more than 200 locations in 27 states and two Canadian provinces.

WNS is a disease that affects hibernating bats and is caused by an invasive, cold-loving fungus. The fungus grows on the bats’ skin, disturbing their hibernation and resulting in dehydration, starvations and often death. First documented in New York in 2006, WNS has since spread to 35 states and seven Canadian provinces. It has been confirmed in 12 North American bat species.

“Some states have been collecting data on their bat populations for a long time,” said Jenny Dickson, chair of the Association of Fish and Wildlife Agencies Bat Working Group. “They’ve looked at that historical data along with data since the arrival of white-nose to get an idea of how WNS has impacted the populations. Having that historical data is critical to monitor WNS.”

A combination of partners has collected the facts, Dickson said. In most cases, it has been fish and wildlife agencies but universities have also collected information and typically they will share that with fish and wildlife agencies.

“This study is taking a lot of information from those different partners and the North American Bat Monitoring Program,” Dickson said. “It is one of the more comprehensive looks that we’ve done for a suite of species.”

Currently, there is nothing to prevent or treat this pathogen, she explained. There have been some promising leads that look good in laboratory trials but doing things in a lab is very different from doing things in the natural world.

Typically bats have only one pup a year, and they live for a long time, so it is not unusual to have bats that are 40 years old (some recent studies show they might live into the 50s), Dickson explained. That combination of slow reproduction and a long life span means that it is going to take decades for populations to recover.

Bats are the largest predator of night-flying insects, the moth-based pests in particular that farmers have to deal with, like earworm and corn borer. In the United States alone, bats are estimated to save farmers at least $3.7 billion a year in pest control services, according to the Association of Fish and Wildlife Agencies.

“We’ve heard from farmers anecdotally who say they have noticed a difference,” Dickson said. “Some have said they’ve had to apply more pesticide to fill in the gap. The folks who are applying a lot of pesticides may not notice a big change. Those who are either working more organically or who try and use an integrated pest management program, they’re going to notice a difference.”

The one thing researchers want to stress is how critically important bats are for the ecosystem services, Dickson said.

“This is something we should all be concerned about because we have seen catastrophic bat population declines in a decade,” Dickson said. “It is going to take us multiple decades to recover from if we can stop it right now. It’s one of the biggest conservation challenges we have faced in our generation.”