By Daniel Dunaief
A recent study of 57 species around the world, published in the journal Science, showed that mammals moved distances two to three times shorter in human-modified landscapes.
Catherine Markham, an assistant professor in the Department of Anthropology at Stony Brook University, contributed to this research, adding information about the ranges for baboons in the Amboseli Baboon Research Project in Kenya.
Marlee Tucker, an ecologist at the Senckenberg Nature Research Society based in Frankfurt, Germany, led the effort, which involved working with 114 other scientists who are studying mammals around the world. Tucker “brought together all these research groups on a scale and scope that had not been undertaken before,” Markham said. “She evaluated in an unprecedented way what the implications of human expansion and development are for wildlife movement.”
According to Tucker, a reduction in animal movement could have ecological implications. “It is likely that ecosystem functions such as nutrients and seed dispersal will be altered,” she explained in an email. “However, whether these impacts are negative, positive or neutral requires further research.”
Tucker suggested that it is “important to maintain landscape connectivity so that animals can move freely,” which could include the creation of corridors that link natural landscapes.
While the study made it clear in a comprehensive way that mammals tend to move less when humans interact with them, it didn’t offer specific indications about the causes of that reduction. Some of that, scientists say, could come from fear, as mammals may avoid humans. Alternatively, some mammals might find a new and concentrated food source at garbage dumps and elsewhere that would reduce the need to travel.
Susan Alberts, a professor of biology at Duke University and a collaborator with Markham on baboon research, said that the “take home message” is that “this is a pervasive phenomenon and occurs on a large scale in the mammalian world.”
Markham has been studying baboons in Kenya at the Amboseli site since 2004. When Tucker reached out to her to see if she could contribute to this work, Markham saw an opportunity to collaborate using information she was already gathering.
As it turns out, baboons in the research project in Kenya live in what Markham describes as a “relatively pristine area” so they did not see “over the time period an increase in the human footprint index.”
Markham shared information about 22 baboons for about 900 days as a part of this research. Tucker’s overarching conclusion included areas where people weren’t encroaching on a mammal’s range. “When she compared the movement of animals living in relatively pristine environments — like the baboons in Amboseli — to the movement of animals living in areas of higher human encroachment, that lead to exciting conclusions,” Markham said. Tucker indicated that future research should focus on exploring the underlying mechanism of the reduction in movement.
In the meantime, Markham is continuing her studies on baboons, exploring the energetic consequences of group size. Larger groups tend to beat out smaller groups when they are competing for food and water in a particular habitat. At the same time, however, those larger groups have stress levels caused by group competition, as one baboon might find the constant proximity and rivalry with another baboon stressful. Baboon group sizes range from a low of around 20 to a high of about 100. Markham is exploring the tension within and between groups.
Over the past few years, Markham, who has been studying this competitive dynamic extensively, has used noninvasive techniques, such as gathering fecal samples, to look for levels of thyroid hormones, which can indicate an animal’s energetic condition.
Alberts explained that Markham was an important contributor to the work at Amboseli, adding that Markham “asks questions at the group level that the rest of us don’t.”
Within the community, Markham has been involved in recent efforts to inspire middle school students at R.C. Murphy Junior High school in Stony Brook to enjoy and appreciate science, working closely with science teacher Dawn Nachtigall, who has been at Murphy for 20 years.
In her second year at Murphy, Markham visits seventh-grade classes several times, discussing her work and explaining how to analyze images from camera traps set up in Kenya and at Sweetbriar Nature Center in Smithtown.
The students receive about 30 photos per pair, Nachtigall explained. Based on the pictures, the students have had to generate questions, which have included whether young deer spend more time with male or female parents, or whether hyenas come out more on full or new moons.
According to Nachtigall, Markham “has such a friendly veneer and an approachable affect” that she readily engages with the students. “She has this wonderful demeanor. She’s soft-spoken, but strong.”
Students in her class appreciate the opportunity to interact with a Stony Brook researcher. “By the end of the period, they are glad to have met her,” Nachtigall added. “Some of them want to become her.”
At the same time, Nachtigall and the other science teachers appreciate the opportunity to hear more from local scientists.
“We live vicariously through her,” Nachtigall said. “It really ignites our own passion for science. Seeing the real-world science for science teachers is just as exciting as it is for students.” Markham is working to post materials online so that teachers and parents can access the information.
A native of Rockville, Maryland, Markham, who joined Stony Brook in 2014, resides in St. James. When she was young, Markham enjoyed the opportunity to join class events in kayaks along the Potomac River. She occasionally saw beaver and bald eagles. Indeed, along the way toward working with baboons, she has also conducted research on bald eagles, monitoring their nests with remote cameras.
As for her work on the Science article, Markham said she is pleased that this kind of collaborative research can provide broad ranging insight to address questions that extend beyond the realm of any one lab or species.