The behavior of large herbivores of the African savannah is governed by the availability of food, which in turn depends on rainfall. A study published in PLoS ONE, proposes to use the movement of elephants to better determine the beginning and end of the period of rainfall and drought in this ecosystem.
So far the limits of the wet and dry African savannah was marked by an arbitrary basis: the months of the calendar. According to research conducted in the Kruger National Park (South Africa) the movement pattern of elephants could be used as a biomarker of seasonal change. The results of this study are published this week in PLoS ONE.
Jane Patricia Birkett, a researcher at the University of KwaZulu-Natal in Durban (South Africa), and colleagues analyzed the migration pattern of 14 female elephant (Loxodonta africana) from different flocks. The movement of animals was followed daily by placing a collar with GPS technology from 2007 to 2009.
The researchers found that all groups of elephants changed their pattern of behavior in two very specific times of the year “at the end of the dry season, just before the start of the first rains, and at the end of the rainy season, when the average rainfall is the most of the year-”, explains Patricia Birkett, first author of the study.
In general, the elephants are moving more and more rapidly during the rainy season (in summer), and reach the maximum travel speed just as the drought begins.
During the dry season, “the nutritional value of food decreases, and this stresses the female” experts say. Your speed is reduced to “conserve energy and probably to exploit smaller areas of more intense.” The minimum travel speed of the elephants is when the rains return.
The important role of the elephant in the ecosystem
“In the African savannah, the resources such as vegetation and water vary with rainfall and temperature, and animals respond to these changes by altering their pattern of movement over time,” the researchers emphasize. Therefore, the distribution of animals not only responds to the varieties of landscape, but also to environmental factors.
Birkett’s team chose the elephant as a model because “it is a key species in the African savannah and its foraging behavior affects many ecosystem processes,” says the international research group.
According to scientists, it is important to know the limits of the seasons to understand many aspects of the environment and the ecosystem in Africa.