Bats Undisturbed By Forest Fires
March 8, 2013

Some Bats Don’t Mind A Good Forest Fire

Alan McStravick for - Your Universe Online

Forest fires are responsible for laying waste to entire ecosystems. As the flames rush through, animals attempt to make their escape, seeking shelter in less incendiary locales. Charred remains of trees and ground cover are completely unsuitable for sustaining the life of the animals that once called the area home. However, a new study led by bat ecologist Winifred Frick of the University of California, Santa Cruz (UCSC) reports the above may not necessarily hold true for all animals.

The survey of local bat populations in burned and unburned areas after a major wildfire in the southern Sierra Nevada mountains established that there was no evidence of detrimental effects on bats one year after the fire. Not only do the researchers suggest that bats are resilient to high-severity fire, they also claim some species of bat may even benefit from the effects of fire on the landscape.

Along with study leader Frick, co-authors Paul Heady of the Central Coast Bat Research Group, John Hayes of the University of Florida, Joseph Fontaine of Murdoch University  in Perth, Australia and Michael Buchalski of Western Michigan University published their findings this week in the online journal PLOS ONE.

The team says its findings are important because current understanding of how wildlife responds to fire is based almost entirely on previous studies that focused on a limited number of species, most of them birds. According to Frick, bats comprise a significant portion of mammalian diversity in forest ecosystems. Their role in the ecosystem is important as they are among the most voracious insect predators.

"This is the first study to directly address species-level response by bats to stand-replacing fire, and our results show that moderate to high-severity fire has neutral or positive impacts on a suite of bat species," Frick said.

The importance of studying animals and their response to fire is relevant as these results may help to inform the public policy debate over forest fire management — specifically, the question of whether to suppress fires on public lands or allow them to run their course.

"A great deal of tension exists between public land managers, environmental groups, and other stakeholders — including homeowners, ranching interests, and the timber industry — over allowing stand-replacing crown fires on public forests," Fontaine said. "This study fills a critical gap on how fire affects an important group of animals."

This current bat study centered in on an area of Sequoia and Inyo National Forests after the 2002 McNally Fire burned in excess of 150,000 acres. Not every area experienced the same level of fire damage, however, and some areas escaped the ravages of the fire altogether.

One year after the McNally Fire, researchers, utilizing high-frequency microphones conducted their survey of the 16 bat species known to live in the area. The microphones were able to sense and record the ultrasonic echolocation pulses bats use to hunt insects. Among the 16 native species, the team separated their echolocation sounds into six distinct ℠phonic groups,´ including three individual species and three groups of species.

Based on their results, the team was able to determine that the responses of the six phonic groups to both moderate and high-severity fire were either neutral or positive. Furthermore, according to Frick, the heterogeneity of the landscape caused by forest fires may even result in a habitat structure that benefits a range of species.

"Bats could be resilient to this kind of natural disturbance," she said. "We go out there and see a charred landscape and we think it's totally destroyed, but the bats may find it a productive habitat for their needs."

While the team agrees that further research on the topic is needed, they claim some species actually seem to prefer a charred landscape for the purpose of foraging. This may be due to reduced clutter that helps to increase the visibility and availability of prey and roosts after a fire. “Fire may provide a pulse of insects immediately after the fire and create roosting habitat later on as snags decay and their bark peels back,” claimed Buchalski.