Topic: College of Sciences and Humanities

August 7, 2008

A Ball State University biologist hopes that the data collected during a recent visit to a national forest in southern Illinois will eventually lead to methods to improve the recovery of a rare and endangered bat.

In a partnership with the U.S. Forest Service, Tim Carter led a student team in May and June to the Shawnee National Forest in southern Illinois to monitor two colonies of Indiana bats. The team was able to collect data by studying an unusually large and healthy colony of about 280 bats.

Indiana bats are medium-sized, gray, black or chestnut mammals listed as an endangered species by the U.S. Fish and Wildlife Service. The species, named after the state where it was discovered, lives primarily in the East, Midwest and in parts of the South.

"During our visit to the forest, we looked at the characteristics of the trees that the bats roost as well as the locations of the roosts on the landscape to see what habitats are needed," he said. "We also examined the temperature of the roosts.

"In addition, we looked at the bats' activity patterns to determine how much time these animals spend feeding and resting. We are comparing the different reproductive stages, including pregnant and lactating, to see if there are differences in needs at different times."

Managing habitat

Carter, who first discovered these colonies in 1999, captured bats by setting up large nets in the forest and then gluing tiny radio transmitters on the backs of females. The captured animals then led the team to the first of two colonies. A typical colony numbers about 100 in a roost tree.

Carter and his students will continue to analyze this data and much more throughout the summer in order to discover many important aspects of the life history of these animals. The analysis will help the U.S. Forest Service to better manage public lands for this rare species. 

"We've just started analyzing the data," he said. "But so far, it looks like the basic needs of these animals are similar to what others have found in other studies of this species. The new and really interesting part will be analyzing the temperature and activity data as that has not been done with this species yet."

Carter expects to have a report completed in 2009.

Environmental impact

Carter points out that like many other species of bats, the Indiana bat is declining due to various factors, including loss of habitat. In 2007 there were an estimated 450,000 animals, down from 883,000 in 1965.

Indiana bats feed entirely on night flying insects and are an integral part of the natural ecosystem, he said.

"As biologists, we have no idea what the impact would be if we were to lose the Indiana bat. It is like parts on your car," Carter said. "Some components like your radio are not essential, and your car will function without it. Other parts like a tire are essential for proper function. We do not fully understand the role that Indiana bats play in the ecosystem.

"We know that they are important insect predators and, along with other bats, help keep many insect populations in check, including many agricultural pests. We can't anticipate the ramifications to the ecosystem of losing the Indiana bat. For that reason as well as simple ethical reasons — like the fact that we caused the decline of this species — we are working hard to recover this species."