Because bats are essential to healthy ecosystem, understanding how climate change affects them is critical in identifying solutions that will help protect populations from adverse effects going forward.

11.01.23

By Kristen Schmitt

A bat drinks from a water tank in Arizona. Photo by Bruce D. Taubert.

Climate change will impact as many as 82% of bat species in North America over the next 15 years, resulting in sharp population declines and the potential to lose some species forever. Because bats are essential to healthy ecosystem, understanding how climate change affects them is critical in identifying solutions that will help protect populations from adverse effects going forward.

Extreme weather events continue to increase in severity and frequency. Widespread wildfires, prolonged drought, higher temperatures, and stronger storms all affect bat populations around the world. Chaotic weather patterns can change the timing of migration- causing mismatch with food resources, wipe out habitat used for roosting & reproduction, and result in an increase in mortality.

Severe droughts, wildfires, and storms impact bat habitat and survivability.
A portion of Mt. Hood Forest after the Oregon 36 pit fire in 2015 and the Riverside fire in 2020. Photo by Rachel Harper.

In the United States, Arizona & New Mexico have the highest bat diversity; but these states have been some of the hardest hit by climate change. The frequency and intensity of wildfires in the West is reducing roosting habitat as thousands of acres of native forest burn to the ground. Along with the complete disintegration of forest, wildfire debris flows into waterways, choking out streams, washing soil into the watershed, and clogging them with debris and ash. This eliminates riparian foraging habitats that bats rely upon during late summer when pups begin to leave the roost looking for food.

Severe drought has dried up a stock tank at Bracken Cave, Texas. Photo by Fran Hutchins.

With climate change, we experience more frequent, longer, and more intense droughts. While droughts drive wildfires, they also reduce water availability in arid environments- which have a high diversity of bats. Droughts mean fewer aquatic insects and less drinking water to quench bats’ hunger and thirst. These factors lead to the potential for a significant drop in bat reproduction rates, as research has found a high dependency on water during this life stage by both pregnant and lactating female bats.

Damage from Hurricane Rita to mature and old growth hollow roost trees, used by Rafinesque’s big-eared bats, in Angelina National Forest. Photo by Mylea Bayless.

Catastrophic weather events like tropical storms, typhoons, and hurricanes are increasing in prevalence across the globe, bringing extreme flooding, high wind, and damage to vegetation. Impacted bats lose habitat and insect prey, as well as clean water, causing fewer pups to be born or survive to adulthood. To cope, migration routes are often altered, causing bats to travel further to find resources necessary for survival.

Climate change is altering our landscapes, creating ripple effects in population growth and declines in species survival. All of this is related. When the forests burn and the drainages dry up, the entire forest structure changes, harming the habitat, the ecosystem, and the bats.