White-nose Syndrome
Eastern North American bat populations are experiencing precipitous declines as a result of White-nose Syndrome (WNS), a highly infectious disease caused by the fungus, Pseudogymnoascus destructans. Since 2006, over several million bats have died from this disease. P. destructans thrives in the cold, moist habitats typical of bat hibernacula. As the fungus grows, it invades the tissue of hibernating bats, causing severe damage to the wings and disrupting physiological systems. In a dormant state, the immune system of bats is suppressed, preventing them from effectively combating infection. While the exact cause of mortality is still unclear, bats with WNS appear to die of starvation, dehydration, and organ failure. There is no known cure at this time, and regional extinction of some bat species has been predicted to occur within 20 years. WNS does not affect humans.
Wind Turbines
A relatively new threat to bats is the construction of wind turbines for alternative energy. Along the east coast of the U.S., wind turbines are responsible for the death of 46 bats per turbine per year, on average. By 2020, it is estimated that wind turbines in the Mid-Atlantic region will kill up to 111,000 bats. While the risk of colliding with turbines or being struck by rotating blades exists, most bats die from internal hemorrhaging caused by the sudden drop in air pressure near the moving propellers. Conservationists are currently exploring strategies to minimize turbine-associated mortality, including ceasing turbine operations during periods of high bat activity.