Elephant Roundtable expert discusses culling

The elephant management issue in South Africa will once again assume centre stage when the department of environmental affairs reconvenes its second Elephant Science Roundtable this August. With so much debate ongoing over the controversial issue of culling elephants, Prof Norman Owen-Smith, one of the scientific experts on the roundtable, has written an article for the University of the Witwatersrand’s alumni magazine, Arena.

Entitled ‘Elephant culling : A measured approach’, the article discusses some of the history of elephant culling in the Kruger National Park (KNP), the current situation, and the role that scientists play in the elephant management debate. Owen-Smith writes, “How should the judgement of scientists be balanced against the ethical issues involved: The killing of highly intelligent animals versus protecting other species and aesthetic values from rampaging elephants?”

He acknowledges that aerial photos show a marked decline in big trees over much of the park, but says that “for scientists thenotion that ecosystems can be held in some stable state has been abandoned…. While some species might lose out, the overall species diversity might not change. Nevertheless, specific concern has been expressed regarding the consequences of the loss of large trees for vultures and other birds requiring big trees for nesting.”

Owen-Smith also points out that much of the tree loss occurred during the time that culling was ongoing, raising the question “As culling had seemingly not prevented the loss of these trees, how few elephants would be needed to halt woodland decline?” He refers to the past management strategyof maintaining Kruger’s elephant population at about 7,000 animals as an “aesthetic carrying capacity” as distinct from the area’s true ecological carrying capacity. “Based on observations in other parks, the elephant population in the Kruger Park could grow towards a regional density of around two animals per square kilometre.”

Owen-Smith points out that in areas like Chobe and Hwange which support much higher local densities of elephants than Kruger, scientists have found that “Woodlands were transformed into shrublands in areas close to water, but plant species affected are widely distributed and declines in the abundance of other animal species were not detected. “Most crucially, the biodiversity outcome of increased elephant numbers in Kruger Park will depend more on the seasonal distribution of the population than on its size.”

This is especially true for bull elephants, who do most of the damage to large trees. “Hence blanket culling does not target the problem…. Other actions, such as removing many of the artificial water sources located in areas away from rivers, could limit the extent of the damage caused to susceptibletrees that grow primarily in upland areas.”

One of the issues discussed at the first round table was the growth rate of Kruger’s elephant population, which has been around six percent annually, close to its maximum rate. “While biochemical contraception might be impractical for an elephant population as large as that in the Kruger Park, natural contraception arising through nutritional deficiencies affecting calf production and survival, as well as the age when females first give birth, will sooner or later become effective.”

Although the last roundtable meeting concluded that there is currently no need for large-scale reduction of elephant numbers in Kruger, Owen Smith reports that the scientists “acknowledged that local management of elephant density, distribution or population structure might be needed to meet biodiversity or other specified objectives in parts of the Kruger Park, as well as in smaller protected areas.” Owen-Smith concludes that “Action may be needed before critical components of biodiversity are lost, but this includes steps besides culling.”

He points out the need for computer models to project interactions between elephants and other parts of the ecosystem, but warns that global warming is likely to change the plant and animal species composition in Kruger within a few decades, “hence killing elephants may be a futile response.” He says that at the roundtable “scientificconsensus was reached” but that “the role of scientists is largely to establish the most effective actions to achieve specified objectives.” However, these objectives are not just determined by scientists, but by all stakeholders in society.