Elephants, Ecosystems and Survival
How are elephants affected by the ecosystems in which they live and by upheavals in their families? What impact do the elephants have on their habitat and neighboring human communities?
The answers to these questions hold a key to the African elephant's long-term survival--and researcher Charles Foley hopes to find them. A Princeton University doctoral candidate who has been studying elephants for nearly a decade, Foley is conducting--with AWF support--a two-year study of the elephants in Tanzania's Tarangire National Park to learn more about the elephant's role in the ecosystem.
In recent years, reestablishing elephant populations devastated by poaching during the 1970s and 1980s has been a major area of interest and attention. And in places such as Tarangire, the effort has been successful.
"More than 3,500 elephants have been recorded recently in Tarangire," says AWF President R. Michael Wright, "making it one of the premier parks for viewing large numbers of elephants in all of Africa." As the population has grown-thanks in part to the CITES (Convention on International Trade in Endangered Species) ban on ivory trade imposed in 1989-the focus has shifted toward understanding the elephant's role in the ecosystem and its relationship to surrounding human communities.
One aim of the Foley study is to find out just where the elephants go in the dry season by tracking matriarchs wearing radio collars. The Tarangire elephants migrate out of the park for water and food, but the rapid growth of human settlements and crop farming has exacerbated relations between elephants and people. If the specific needs of the elephants can be identified and their migratory patterns analyzed, as Foley proposes, then management plans can be made to protect animals and humans alike.
The project will also survey areas used by the elephants to determine their impact upon the environment, and vice versa, to get a clearer picture of elephant migration routes outside the park. Finally, Foley will attempt to assess the long-term impact of past poaching on the elephants' social system-an area of research not yet explored. (AWF's Cynthia Moss, during more than 25 years of research in Kenya's Amboseli National Park, has generated valuable findings on the social systems of stable elephant populations.)
Foley has already drawn some conclusions from his many years of working with Tarangire's elephants. "Poaching is a selective process," Foley told the Wildlife News. "First they go after the old bulls, who have the biggest tusks, and then they go after the old females, mostly because they are good targets." Matriarchs, usually age 25 or older, are easy to spot, he says, because their bodies "stop growing upwards and elongate like a sausage."
Foley's research indicates that when matriarchs die, younger elephants--particularly females--have a harder time learning the skills necessary to survive dry seasons and tend to wander-often with their calves-from group to group, disrupting group dynamics. Thus, removing older females from the ecosystem can have what Foley calls "dramatic effects." He has also found that poaching increases stress levels of female elephants, which in turn affects pregnancy and birth rates.
The information that Foley will glean from this comprehensive study of Tarangire's elephants, says Wright, "is potentially precedent setting, because to date only generalities are known."