by Darren A. Miller, Ph.D.
Research on America's forest-dwelling bats has mostly involved older, unmanaged forests, although much of America's woodlands are now commercially managed tracts. How well can bats adapt to managed forests? And how can we best manage for timber and bats within these forests?
Weyerhaeuser Company, one of the world's largest forest-products companies, has decided to begin answering those questions. As a certified wildlife biologist and Weyerhaeuser's Southern Wildlife Program Manager, I embarked on a two-year research effort in managed pine forests in Mississippi.
The 2000-01 project with Francisco Vilella of the Cooperative Fish and Wildlife Research Unit at Mississippi State University and graduate student Leslie Welch made some encouraging discoveries about roosting habits of the eastern red bat (Lasiurus borealis). Previous work had concluded that the red bat preferred roosting in the foliage of large hardwood trees, which are uncommon in managed pine forests.
Tracking red bats with tiny, glued-on radio transmitters, however, revealed that they are much less picky about their roosts. We tracked the bats to 140 roost trees of 17 different species. The trees chosen for roosts ranged in size from just over an inch (2.5 centimeters) in diameter to more than 32 inches (81 centimeters). Red bats, like most other species that roost in foliage, change roosts frequently - almost every day in our study.
We also found that the average size of the home ranges of red bats was 203 acres (82.2 hectares) for adult females and 363 acres (146.9 hectares) for adult males. Our results, like those of other researchers, show that red bats can make themselves at home in a wide variety of forest types and managed pine forests most likely provide acceptable habitat for this species.
We are just beginning to understand the habitat needs of bats in southern forests, especially industrial pine forests. Continuing research should provide much information to help managers incorporate bats in their forest-management plans.
(The Mississippi project was funded by Weyerhaeuser Company, Bat Conservation International's Bats and Forests Initiative, the National Council for Air and Stream Improvement, and International Paper. The Bats and Forests Initiative is supported in part by the National Fish and Wildlife Foundation and the National Forest Foundation.)
BCI members can read the full story of Darren Miller's bat research in Mississippi and Georgia in the Spring 2003 issue of BATS magazine.
