September 27, 2011
Along the Cherohala Skyway that runs through the Cherokee and Nantahala national forests in Tennessee and North Carolina, a team of four Indiana State University scientists glowed in the falling mountain light thanks to their orange safety vests.
The four scientists bent over and peered into the connecting seams of the concrete bridge's walls. The 13-centimeter cracks, no wider than a pen or a 70-page notepad, provided homes for eastern small-footed bats and the occasional snake.
After a whispered consultation, the four decided to capture the bat waiting for nightfall in slot seven. Jen Heemeyer, who graduated in May 2011 with her master's degree in biology, inched a yardstick up the seam, bringing the protesting, chittering bat into the declining evening light and into her and Joy O'Keefe's hands.
Catching bats from the bridge was only one part of the research O'Keefe, ISU assistant professor of biology, conducted this past summer. Two teams of Indiana State students and technicians spent their summer working in the southern Appalachian Mountains on three projects researching the federally endangered Indiana bat, the little-known eastern small-footed bat and acoustic activity of bats.
Tara Thomson, a graduate student in biology from Duluth, Ga., began her field research investigating characteristics of the natural roost sites of eastern small-footed bats. She and the team captured and attached transmitters to the bats.
"They're a very rarely observed species because they're so small," Thomson said about the bats that as adults weigh between 4 and 6 grams, about the weight of one nickel, which weighs 5 grams. "They mainly roost in small aggregations."
Thomson found it exciting to research a little-known species, which could be put on the federal watch list.
"It's awesome knowing that you're one of the first people to figure all of this out," she said. "I can publish information that no one else knows."
What they have found in their tracking has surprised them.
"We were assuming that they wouldn't really fly that far to get to their natural roost sites. In one of the studies that has been done before, eastern small-footed bats really didn't move that far at all," Thomson said. "Our first bat actually moved five and a half miles from the bridge where we captured it. It took us four days to find him. The good thing was that he was roosting in a rock crevice like we expected him to."
Danny Schaefer, a senior biology major from Terre Haute, worked with Thomson in researching the eastern small-footed bat. His used an Anabat bat detector to record bats' echolocation calls.
"I've learned quite a bit about identifying different species of bats when we've been catching bats and learning a lot about the acoustic calls and distinguishing among species, and high frequency and low frequency bats," he said. "Hopefully, I'll be getting a lot more into that in the semester when I'm actually analyzing the data."
"There hasn't been a lot of call data to know how to distinguish (the eastern small-footed bat) from other species," Thomson said. "Using the Anabats is a way to research bats without putting our hands on them. It's a really great way to passively study bats."
Although in the Midwest the Indiana bat has been studied extensively, that is not true in the southern Appalachians.
"They were only discovered to be roosting here in the summer about 10 or 12 years ago and we're following up on some of the early pilot work to get a better understanding of what types of trees those bats are using," O'Keefe said. The bats roost in dead yellow pine or white pine trees. "We're interested in the effects of prescribed fire on those dead pine trees. Prescribed fire here in this region is used to regenerate pine and oak habitats, but fire also consumes dead trees."
O'Keefe began researching bats in the Appalachians while working on her doctoral dissertation, drawn there by the bats seeking refuge in a changing landscape surrounded by the cities of Knoxville, Tenn., Atlanta, Greenville, S.C. and Charlotte, N.C.
"This area is a haven for forest bats and we find a greater diversity of species here in the mountains than we would if we moved just a little bit east, west, north or south," she said, adding that 14 species may be found in the area. "There's not a lot known about the bats that live here."
To help gain that understanding and to further students' skills, O'Keefe brought Indiana State students to the Appalachians to research their own projects.
"I think it's tremendously important to get the students out in the field and have them experience hands-on what it takes to be a researcher," she said. "I want to get them skills that they need to go out and get a job when they finish their undergraduate or graduate degrees. I want them to be competitive in the workforce and so I want to expose them to as many different techniques as possible and then get them thinking about how to take what they've learned and translate that into something that can be understood by resource managers that work for agencies so that we can actually better conserve populations of animals we are concerned with here."
From tracking the bats up rock faces to assisting in transmittering bats, Schaefer thinks the experience will only help him in his future.
"It's a great hands-on experience," he said. "I'm learning a lot, taking a lot from it. Getting this experience, that's definitely a huge step forward. I don't know if I would be able to get the same experience elsewhere."
Kristina Hammond, a biology graduate student from Heartland, Vt., worked with O'Keefe investigating Indiana bat habitats but concentrated her research on reproductive females regarding their use of torpor, a lowering of their body temperatures, to conserve energy during the day.
"Reproductive individuals use torpor less because it inhibits gestation and milk production, which is very important for the growth of their pups because you want your pups to grow as fast as possible, put on weight as fast as possible and get ready for winter as fast as possible," Hammond said. "I'm trying to get a window into what they are doing to make up for loss of energy conservation. What other forms of energy conservation are they using?"
Through the use of a data logger, which records body temperatures and is tuned to the transmitters' frequencies, Hammond knows when transmittered bats go into torpor, when they leave the roost site and how long they stay out.
"We've seen a difference between our pregnant and lactating females. Pregnant females will go out for eight, nine hours a night and forage all night and not come back until right before dawn," she said. "Whereas when they have their pups, we've actually seen one of our pregnant bats shift her behavior. She'd go out for two, maybe three hours then come back for an hour, then go out for another two or three hours. So you can tell she's now concerned about that pup she just gave birth to."
A nearby stream burbled while katydids whirred in accompaniment at the gloaming in Great Smoky Mountains National Park. Beeping wristwatch alarms, set to eight minute intervals, broke through the conversation and night sounds.
Every eight minutes a pair of the researchers left the worksite to check the mist nets, where they found tri-colored bats (also known as eastern pipistrelles), other northern long-eared bats and big brown bats. But, the Indiana bat, the subject of their research in the Appalachian Mountains in North Carolina and Tennessee, remained elusive. For 10 nights, the research team that includes O'Keefe and Hammond, had set up nets searching for the bat. Each night their nets remained free of the federally endangered bat.
After an hour and a half of trips, two researchers walked out to check the four nets set up around streams and a park trail. At the first net, Dottie Brown, the project's lead technician, turned her head running her head lamp's light down the length of the finely woven mist net. Nothing. The next net yielded nothing. In the third net, Brown freed a beetle. In the last net, as Brown began to run her light along the net, the light caught the snared furry body of a struggling Indiana bat.
Because of Indiana bats endangered status, they can only be held for 30 minutes. The researchers worked together to measure and weigh the juvenile male Indiana bat, which weighed 6.75 grams, about the weight of three dimes.
"You're huge," O'Keefe told the bat. "You can totally handle a transmitter."
While attaching a transmitter, they hoped the bat would lead them to a primary maternity roost tree, where he might roost with other Indiana bats.
As O'Keefe opened her gloved hand to release the bat back into the night, she urged the bat onward with "Go, go, go."
Joy O'Keefe, assistant professor of biology, assists Jen Heemeyer with capturing an eastern small-footed bat. ISU Photo/Tony Campbell
The eastern small-footed bat. ISU Photo/Tony Campbell
Joy O'Keefe attaches a transmitter to an Indiana bat. ISU Photo/Tony Campbell
Joy O'Keefe and Katherine Caldwell, field technician, check an Indiana bat's wing conditions. ISU Photo/ Tony Campbell
Kristina Hammond, a biology graduate student from Heartland, Vt., releases a bat into the night. ISU Photo/Tony Campbell
Contact: Joy O'Keefe, Indiana State University, assistant professor of biology, at 812-237-4520
Writer: Jennifer Sicking, Indiana State University, associate director of media relations, at 812-237-7972 or Jennifer.Sicking@indstate.edu
Two teams of Indiana State students spent their summer working in the southern Appalachian Mountains on three projects researching the federally endangered Indiana bat, the little-known eastern small-footed bat and acoustic activity of bats.