Fleshing Out the Predator-Prey Balance

Saturday, January 18, 2014

David Christianson sleeps next to lions. For an expert in large mammal conservation and ecology, that's just the nature of the beast.

Christianson, an assistant professor in the School of Natural Resources and the Environment at the University of Arizona, focuses on large mammal behavior and the predator-prey relationships of Africa's most iconic carnivores and herbivores, as well as elk and wolves in Montana and the endangered Sonoran pronghorn in the southwestern United States.

By studying the behavior of these animals, Christianson hopes to identify why certain species or populations teeter on the brink of extinction and what forces determine whether they live to flee or fight another day, regardless of where they fall on the food chain. 

"Populations ebb and flow, sometimes disappearing." Christianson said. "The role of carnivores as ‘killers' is one force we often look at to try to understand these dynamics, but predation alone can be a poor explanation for the trends we see in prey populations. That's partly because predators can play a larger role in the ecosystem beyond simply killing and eating prey."

One of Christianson's projects involves better understanding how predation risk from large carnivores drives the behavior of large herbivores in Zambia in southern Africa. As co-investigator on the project, he collaborates with Montana State University and the Zambian Carnivore Programme, a non-profit trust dedicated to conserving the region's large meat eaters, to study the ways populations persist. In particular, they examine behavior in dominant herbivores such as wildebeest, antelope, and Cape buffalo in relation to lions, cheetahs, African wild dogs, leopards, and hyenas.

Christianson also has assisted conservation and resource managers with reintroducing lions to Liuwa Plain National Park in western Zambia, where proximity to the Angolan civil war and poaching had reduced the lion population to a single lioness by the late 1990s. A documentary film features this "Last Lioness," Lady Liuwa, who slept near Christianson's tent when he last visited there.

During the Liuwa Plain project, one 250-pound lioness bolted toward the park boundary. Christianson helped track and dart her, but she plunged into a swamp before the tranquilizer completely kicked in.   

"She was in the water with her head barely above the surface," Christianson said. "Every time she almost fell under sedation, I had to tug her tail to keep her awake. Eventually, once she was completely sedated, I held her head until we could pull her out of the swamp and into the helicopter sling."

Read more from this 2013 feature of the UA Environment and Sustainability Portal at the link below.

More Information