Population studies are critical for vulnerable and endangered animals because they help conservationists determine what efforts are needed to help the remaining populations persist.
One such animal is the wild cheetah. According to the International Union for Conservation of Nature’s Red List of Threatened Species, cheetahs have vanished from approximately 90% of their historic range in Africa, and are extinct in Asia except for a single, isolated population of perhaps 50 individuals in central Iran.
With the world’s wild cheetah population now numbering less than 7,000, an accurate estimate of numbers and densities across their range are critical to sound conservation and management efforts and choices.
To help provide the key data needed for effective stewardship and protection of this vulnerable species, three MSU alums—all formerly part of MSU’s Ecology, Evolutionary Biology and Behavior program—launched a cheetah population study almost 16 years ago.
A paper on the long-term study and its progress to date was recently published in the journal Population Ecology.
The project began in 2004 when Stephanie Dloniak, now adjunct assistant professor in the MSU Department of Integrative Biology in the College of Natural Science, received funding to conduct the first cheetah population study in the Masai Mara National Reserve.
“In 2005, I couldn’t believe that no one had estimated the number of cheetahs inside the Masai Mara, one of the world’s most famous wildlife areas—and definitely one of the most important carnivore areas,” said Dloniak, who also serves as chair of the International Union for Conservation of Nature Hyena Specialist Group (IUCN HSG). “The Mara-Serengeti is one of the best, if not the best, large carnivore strongholds that we have.”
Over a 10-month period that year, Dloniak traveled throughout the 1,500 square kilometers of the MMNR, visiting all accessible areas repeatedly to collect sightings and re-sightings of individual cheetahs following the traditional capture and recapture method, but with a twist.
Instead of literally capturing each cheetah, Dloniak photographed every cheetah she saw, being sure to snap both sides of each subject to record individual spot and tail ring patterns, which are as unique as human fingerprints. She also noted where and when each cheetah appeared, as well as its sex, age class and behavior.
“Basically, I’d drive around a section of the Mara each day, varying the area regularly to ensure I covered the entire 1,500 square kilometers several times,” Dloniak said. “When I saw a cheetah, I’d record the location using a GPS and then photograph their spot patterns so I could distinguish new individuals versus re-sightings.”
Dloniak recorded more than 40 individual cheetahs in 2005, and the modeling revealed an average density of 1.2 cheetahs per 100 square kilometers—a very strong population density.
In 2013, cheetah researchers Elena Chelysheva and Salim Mandela of the Mara-Meru Cheetah Project began collecting new survey data in the MMNR. They teamed up with Dloniak and two other MSU alums (David Green, currently a research associate at the Institute for Natural Resources, Oregon State University; and Daniel Linden, now a biological statistician for NOAA’s National Marine Fisheries Service) to examine whether the cheetah population size had changed over time.
Their initial analyses indicated a decline of almost 50 percent in MMNR cheetah numbers since 2005, piquing their interest in expanding the project.
In 2016, another group of scientists studying cheetahs in the area released data that suggested there was no decline in the cheetah population density in the greater Mara for 2014. Dloniak and her team asked why and decided to use additional years of data that Chelysheva and Mandela had continued collecting to explore the discrepancy.
In addition, Linden chose to expand the analysis of their data using a more complex version of their spatial capture-recapture model, leveraging information on the environment and the timing of their surveys.
“Because where an individual animal is captured or encountered relates to where that individual lives,” Linden explained, “the spatial capture-recapture model allows us to apply a form of reverse engineering to determine an animal’s ‘home range’ based on the pattern of spatial detections. This information allows us to assess how individual movements interact with our spatial surveys to produce the data collected.”
The group also added photographic survey data to the project from 2014 to 2016, noting that the data often varied from year to year due to a number of transient young male cheetahs that moved in and out of the MMNR. This variation, it turned out, didn’t suggest population loss from year to year as much as it showed a roaming male population that occasionally skewed annual counts but may not have been indicative of population health overall.
“We were really happy to see that the Mara cheetah population is stable,” Dloniak added. “With this extensive data, we have strong evidence of stability even if there are annual fluctuations in observations due to cheetahs moving around a lot.”
The study continues. The team now has data from 2017 to 2019 and is collecting data for 2020. They have plans to refine their analyses and incorporate more mechanistic models of spatial population dynamics to it, including individual survival and immigration to improve the understanding of cheetahs in the MMNR.
“What I love about this story is that three MSU EEBB alums worked together,” Linden said. “I spent eight years in East Lansing and I’m a passionate Spartan; my life was changed there, so it’s good to know we could come together and produce something that hopefully furthers wildlife conservation, especially in the Mara.”
Dloniak agrees.
“David and I both did our doctorates in Professor Kay Holekamp’s lab at MSU, and were instructors on the Behavioral Ecology of African Mammals (BEAM) study abroad course. It is a testament to Kay’s mentorship and the opportunities she gave us, and MSU’s EEBB graduate program, that we continue to work together on interesting questions across disciplines, species, and many time zones!”
Banner image: Five young adult male cheetahs are a formidable coalition in the Masai Mara, and a symbol of the health and stability of the population. Photo credit: Dr. Elena Chelysheva, Mara-Meru Cheetah Project, Kenya