Climate change, disease threaten North American bats

TRAVERSE CITY, Michigan (AP) —

More than half of North America’s bat species are likely to decline significantly due to climate change, disease and habitat loss, scientists warned Monday.

A report by experts from the United States, Canada and Mexico says that 81 of the 154 bat types known on the continent “are at risk of severe population decline” over the next 15 years.

The “state of bats” report was released by the North American Bat Conservation Alliance, a consortium of government agencies and private organizations.

“They need our help to survive,” said Winifred Frick, chief scientist at Bat Conservation International, one of the participating groups. “We are facing a global biodiversity crisis and bats play a very important role in the healthy ecosystems needed to protect our planet.”

According to the US Geological Survey, bats give US agriculture an annual boost of $3.7 billion by devouring crop-destroying insects. Some are plant pollinators. Bats also serve as prey for other animals, including hawks, owls, and weasels.

Millions of people have died since 2006 from a fungal disease called white-nose syndrome, which attacks hibernating bats and creates fuzzy patches on their faces and wings. It causes them to wake up early from hibernation and sometimes fly out. They can burn off winter fat stores and eventually starve.

Eight U.S. bat species are listed as endangered or on the verge of extinction.

Last year the Federal Fish and Wildlife Service designated the northern long-eared bat as endangered and proposed listing for the tricolor bat. The little brown bat is being evaluated for a potential listing. White nose syndrome is the primary killer for each of the species.

More than 150 agencies, nonprofits and universities are collaborating to fight the disease, said Jeremy Coleman, a wildlife biologist who coordinates service engagement and co-authored the report.

Methods under development include vaccines, antifungal sprays, and ultraviolet light treatments for hibernation spots.

“We have a number of tools that are showing great promise,” Coleman said. “There is very little precedent for managing a wildlife disease, especially one so devastating and pervasive.”

The report says bats are also endangered by forest fragmentation: logging and urban sprawl in Canada, fire suppression in the United States, and cattle ranching in Mexico. Many bats live in older trees during the summer.

People sometimes disturb hibernating bats in the winter by exploring caves and abandoned mines.

Climate change is expected to intensify the challenges, causing more extreme storms and temperature swings. The report says that 82% of the continent’s species are at risk from the effects of global warming.

More than 1,500 bats were rescued in December after suffering hypothermic shock during a flash freeze in Houston, where they lost their grip and fell from roosting spots under bridges.

Drought and increasingly arid conditions will leave bats with less drinking water, killing some and preventing others from breeding, the report said. As surface waters dry up, there are fewer places to fly over for aquatic insects.

Ironically, wind turbines, a major source of renewable energy that can help slow climate change, pose another problem for bats. An estimated 500,000, representing 45 species, die each year in collisions with structures, the report said.

But those figures were based on 2021 calculations, said Frick, a research associate professor of ecology at the University of California at Santa Cruz in addition to his position at Bat Conservation International. Since then, so many turbines have been built that the latest estimate is 880,000 dead.

His organization is collaborating with manufacturers and others to research solutions, including acoustic devices that cause bats to steer clear of turbines. Reducing the rotational speed of the blade, particularly during the fall mating season when bats are particularly active, would help, Frick said.

Cori Lausen, director of bat conservation at Wildlife Conservation Society Canada, who was not involved in compiling the report, said it provided a solid overview of the plight of North American bats. But some guys she described as “seemingly secure” based on their current status have bleak prospects, she said.

“The government process is slow, deciding when to list a species and when not. If anything, this report is a bit conservative,” Lausen said. “Many of these bats shouldn’t be listed as OK.”


Follow John Flesher on Twitter:


The Associated Press’s climate and environmental coverage receives support from several private foundations. Learn more about AP’s climate initiative here. The AP is solely responsible for all content.

Leave a Reply

Your email address will not be published. Required fields are marked *