Elephants in the Addo Elephant National Park force rhinos to eat low quality grass.
In a limited but unique study just published in PLOS ONE there seems to be evidence that when elephants and black rhino live in the same area the rhino loses out in the browsing game and rely on stored body fat and lower quality grasses. This could be important in rhino conservation policy as elephant numbers in South Africa increase.
The study was undertaken at the Addo Elephant National Park, South Africa and the researchers looked at elephant and rhino droppings to see what sort of food competition there was between the two so called megahebivores.
Although the study was in quite a small area the results did show a clear seasonal separation of resource use between the two animals and when there were no elephants the rhinos expanded their browsing habits away from poor quality grasses and back to their more ‘normal’ shrub browsing.
The researchers from the Nelson Mandela University in South Africa and University of the Sunshine Coast, Australia, point out that trying to manage areas with high densities of elephants could impact on other browsers such as the rhino.
Being aware of potential competition issues is import and despite many African countries seeing their elephant population killed off by poachers the elephant population in other countries such as South Africa is growing at a healthy rate. In some parts of Africa the elephant population has even extended beyond the carrying capacity of the local region.
In South Africa, for instance, despite the elephant population hitting a low point of just 120 elephants in 1920 there are now over 12,000 elephants in the country. Many of the local populations are in fenced wildlife reserves and parks which could lead to overcrowding. In the Addo Elephant National Park where the study was undertaken the elephant population is growing at a rate of 5% a year.
Some areas of Addo have had to be fenced off to keep elephants out to help conserve some of the rare plants of the park. Could there be a time when parts of wildlife reserves in Africa are fenced off to elephants in order to help give the extremely rare black rhino a chance of survival?
The researchers make it clear that their study is a small look at competition between elephants and rhino in a small area and much more work needs to be done to confirm the finding. It could though make a difference in future wildlife conservation policy in southern Africa.
External sites:
PLOS One: Shift in Black Rhinoceros Diet in the Presence of Elephant: Evidence for Competition?