The North American Bat Conservation Alliance says more than half of the continent’s 154 known bat species could face “severe population decline” over the next 15 years, putting agriculture and ecosystem relationships at risk. White-nose syndrome has devastated bat populations since 2006, and forest fragmentation and climate change are further stressing the animals, but scientists are working on solutions to blunt the disease’s impact, including vaccines, sprays and ultraviolet light for clearing the fungus that causes the disease.