Professor Cerling used analysis of carbon and other isotopes in the tail hair of African elephants (Loxodonta africana) to find out their dietary preferences. The research team added Global Positioning System mounted on radio collars to monitor the movements of animals. This was a useful adjunct to the experiment. The area selected for the unique experiment was Buffalo Springs National Reserves in northern Kenya.
Vivid Mosaic of Nature
The study gave a vivid picture of the interplay of rainy season, growth of grass, elephants’ eating habits and their breeding and parturition. The outcome was a fascinating mosaic of events that can be used by conservationists in the management of elephant reserves.
Season, Diet and Tail
Two weeks after sprouting of grass the grass grows to a height where the elephants can grab it with their trunks. Here an analysis of elephant tail hair showed different forms of carbon. It also gave a clear-cut indication of peak levels of high-protein grass. During dry seasons, isotope ratios showed the elephants switching over to trees and shrubs.
Conception and Birth
Five weeks after the rainy season starts the grass is very rich in nutrients and the elephants gorge on it. Females in the 800-member Samburu-Buffalo Springs elephant population become perfectly fit and ready to conceive. 22 months after the conception the elephants start giving birth. Peak births occur just in time for another rainy season and this ensures enough water and grass for the offspring. Fifty to sixty calves are born annually in the Samburu-Buffalo Springs
Impact of Overgrazing by Domestic Animals
The research also brought to light the impact of overgrazing by cattle on the typical wet season diet of elephants. According to the researchers competition with cattle results in poor access to high-quality grass forage because cattle keep the grass very short to the disadvantage of elephants. The increased competition for grass with domestic cattle might threaten the elephants' ability to bulk up for pregnancy.
Utilization of Water and its Impact
Another important finding of the research was the variability in the utilization of water. During the course of dry season, rivers tend to be very dry and have different isotope ratios than in rainy season. This brings about remarkable changes in the isotope composition of the blood of elephants, which in turn is reflected in the isotope composition of the hair.
Real Benefits of the Study for Conservation
The advantage of the latest monitoring technique is that even without any one monitoring on the ground, tail-hair isotope analysis provides a record of the elephants’ diet and behavior across its entire range. This has enormous conservation significance. Park managers devising ways of management for elephants, in this time of increased pressure of humans on the environment, would find the new methods highly appropriate for their needs. The findings have been published in the online edition of the journal Proceedings of the National Academy of Sciences.
References
Stable isotopes in elephant hair document migration patterns and diet changes. Thure E. Cerling,George Wittemyer,Henrik B. Rasmussen,Fritz Vollrath,Claire E. Cerling,Todd J. Robinson,Iain Douglas-Hamilton. Journal Proceedings of the National Academy of Sciences
Mohan Alembath - I am a retired wildlife warden who has put in 30 years service in the wildlife reserves of Kerala,India. I was trained at Forest College ...
