Many of the 1,300 species of bat are considered to be threatened and declining. A new analysis reveals trends and causes of death in bats around the world, shedding new light on the possible factors underlying population declines.
In the analysis, 1180 mortality events, each involving more than 10 bats, were represented in a detailed canvassing of the literature dating from 1790 to 2015, and could be divided into 9 categories.
Prior to the year 2000, intentional killing by humans caused the greatest proportion of mortality events in bats; the reasons for killing varied with region, but bats were killed as pests, for food, for vampire bat control, and to protect fruit crops. Since 2000, collisions with wind turbines and white-nose syndrome (in North America) have been the leading causes of mass mortality in bats. Storms, flooding, drought, and other abiotic factors also cause mortality, and are likely to increase with climate change.
The analysis is published in Mammal Review.