Climate change and human encroachment are making it hard for a young family of elephants to survive in the African savannas of Kenya, and a University of Utah-led study is pinpointing what can be done to save them.
The findings, which traced the diets and movement of "the Royals," Victoria, Anastasia and Cleopatra — three daughters of a mother elephant named Queen Elizabeth, who died of old age the first year of the study — were published Monday in the online edition of the journal Proceedings of the National Academy of Science.
"There are some elephant families that are good friends and socially near other elephant families, and some families that don't like each other and actively avoid each other," said Thure Cerling, a distinguished professor of geophysics and biology at the U. The Royals are "one of the dominant families, like the cheerleaders in high school. They camp out in the best places, where the food and water are best."
Cerling, the lead researcher, used Global Positioning System tracking collars and analyzed carbon and other isotopes in tail hair to monitor the elephants' behavior over a six-year period from 2000 to 2006.
Despite the locations they choose to feed, Cerling believes that changing environmental conditions, such as an infiltration of cattle in the area, are making life more difficult for the elephants.
With elephants endangered and their food sources threatened by climate change and human encroachment, tail-hair isotope analysis "provides a record of their diet and behavior" to guide conservation efforts, he says. "We get a continuous record of their diet even though we don't have anyone on the ground watching them."
By analyzing carbon isotope ratios along the length of a single elephant hair, the researchers could see the twice-annual switch when rain falls in the Samburu and Buffalo Springs reserves, and the elephants go from eating mostly trees and shrubs to eating mostly grasses, and then back again.
"The impact of overgrazing by cattle on the typical wet season diet of elephants is clear," researchers in the study stated. "Competition with cattle results in poor access to high-quality grass forage because cattle keep the grass very short and out-compete elephants."
The findings provide a hint that as Kenya's population continues to burgeon, and as global warming produces more droughts, increasing competition for grass with domestic cattle might threaten the elephants' ability to bulk up for pregnancy. When the elephants can't eat what they need, the herd could suffer, according to the research.
Cerling conducted the study with two U. colleagues, James Ehleringer and Christopher Remien, as well as conservation biologists George Wittemyer of Colorado State University and Save the Elephants in Nairobi, and Iain-Douglas Hamilton, who founded Save the Elephants and is affiliated with Oxford University. They hope to continue monitoring the elephants, including other families for another 10 to 15 years, which will allow them to "look at how climate and land use change affect the elephants," Cerling said.