In just 7 years, a fungal disease known as white-nose syndrome has killed more than 5 million North American bats, nearly wiping out entire colonies, according to a new study. The disease, named for its initial discovery as a white fungus growing on bat noses, drains hibernating bats of their energy reserves. It was first discovered in North America in 2006 and spread rapidly, causing massive declines in bat populations across the northeast. To quantify the localized impact of the disease at known hibernation sites, scientists used 4 decades of population counts collected between 1976 and 2013 from more than 1000 winter colonies inclusive of six North American bat species and 10 European bat species for comparison. Prior to the emergence of white-nose syndrome, bat colonies in eastern North America were 10 times larger than those in Europe, the team reported online ahead of print in Global Ecology and Biogeography. Following the disease outbreak, however, populations fell to the low levels seen overseas, where the white-nose syndrome has been present for decades. Moreover, the researchers identified massive population declines, ranging from 60% to 98% for all six North American bats studied, and extensive local extinctions, the most severe being for the northern long-eared bat (pictured above), which has disappeared from 69% of its former hibernation sites. As important predators of nocturnal insects, bats are considered to be among the most overlooked, yet economically important, nondomesticated animals in North America. Resulting increases in mosquitoes and agricultural pests could have ecological and economic consequences for the continent, including financial losses from damaged crops and increased spread of human diseases.

*Correction, 6 February, 3:36 p.m.: The last sentence of this item was initially attributed to the researchers behind the new study. The attribution has been removed.