The elephant population problem in Zimbabwe: Can there be any alternative to culling?

C M Foggin

Wildlife Veterinary Unit, P/Bag BW 6238, Borrowdale, Zimbabwe


Aerial counting of elephant populations has been carried out in Zimbabwe since 1967. The latest census in 2001 revealed a total of approximately 88100 elephant in 4 separate populations (Table 1)

Table 1: Aerial Census of Zimbabwe’s Elephant in 2001

The total population has increased from an estimated 47,000 animals in 1980, with the greatest percentage increase occurring in Hwange National Park (HNP) which, on its formation in 1928, was believed to contain between 1000 and 2500 elephant. Overall, Zimbabwe’s elephant population has been increasing at approximately 5% per annum, and is therefore likely to be as high as 97,000 animals at the present time (Figure 1).


Figure 1: Elephant population increases in Zimbabwe, nationally and in Hwange National Park


In Hwange National Park (HNP), the provision of some 70 artificial, perennial water points has increased the dry season foraging range of elephants from 35% to 75% of the Park’s total area. Elsewhere, compression of the elephants’ range by the increase in the human population from 0.5 million in 1900 to 12.5 million in 2001 and the recent “land crisis” has raised elephant densities to as high as 6 per km2. The major effects of this increase in elephant density have been erosion, vegetation damage and the loss of biodiversity. Erosion has occurred as a result of the loss of tree cover and has led to the siltation of water points. Vegetation damage has included a severe loss of trees which, combined with uncontrolled fires, has caused a loss of palatable species of shrubs and grasses. The effect of the elephant over-population on biodiversity has been less easy to monitor. It has been estimated that at densities of < 0.5 elephant per km2, forage and biodiversity may actually be enhanced, while higher densities lead to a loss of biodiversity. Of particular concern has been the effect on rhino in HNP. They are now unable to utilize areas under heavy elephant pressure and may even be prevented from access to some water points.

In addition, there has been more human-elephant conflict because of increased damage to crops and water facilities. These elephant attacks are likely to increase since 15% of Zimbabwe’s elephant live outside the protected areas. The recommended elephant population for Zimbabwe is around 35000 - 40000 animals (0.6 per km2).

Efforts to control the elephant population
Cropping elephants by shooting was instituted in 1960, and by 1988 some 44000 elephants had been shot, mostly by eliminating whole breeding herds. Between 1989 and 1995, when elephant culling was stopped, approximately 2500 more animals were shot in problem animal control operations. In the 1980s, it was proposed that the number of elephant in HNP be reduced and held at 13000 (< 1 per km2). Although this target was reached in 1985, the policy was not continued and the population has been allowed to increase unchecked, to the point where a “die-off” is likely to occur in the Park in the near future.

No plans exist to re-institute cropping of elephant in the protected areas. This has resulted from international pressure against elephant culling and a lack to resources within the Parks and Wildlife Management Authority of Zimbabwe to undertake such large-scale operations.

Options for the future
Options for future control of elephant in Zimbabwe include a laissez-faire approach, culling, translocation and contraception. Inactivity will lead to massive die-offs in some areas of the country such as HNP, Chizarira and Mana Pools National Parks. It would also result in an unacceptable loss of vegetation and bio-diversity. For culling to be reinstated, the necessary resources would have to be found in a country that already faces a severe economic crisis. Even if it could happen the task will be difficult. At the peak of culling in the 1980s, a maximum of 5340 elephant were shot in one year. If that total could now to be increased to, say, 10000 per annum, the recommended total population of 40000 would only be attained after 10 years of sustained effort.

However, an attraction of culling would be the sizeable economic return if the skin, ivory and meat could be recovered and successfully marketed. It has been estimated that a 5% off-take of excess elephant by a combination of safari hunting, culling and problem animal control could return as much as US$ 320 per km2. This compares favourably with the calculation of US$ 200 per km2 to manage an intensively protected wildlife area, particularly when only US$ 10 per km2 is presently available in Zimbabwe. However, culling is not generally acceptable to the international conservation community, and Zimbabwe would probably receive widespread condemnation if large numbers of elephant were shot.

Translocation of elephant breeding herds was undertaken in Zimbabwe in 1992/3, when around 1000 elephant were successfully moved from Gona-re-zhou National Park following a severe drought. Most were moved to the nearby Save Valley Conservancy, and 200 were taken to South Africa. Therefore, mass translocations are certainly feasible, but they are very expensive at > US$ 1500 per animal and there are few areas to which the elephant can now be moved, all of which are outside Zimbabwe. Translocation cannot therefore be considered seriously as an option for significant population reduction.

Contraception or sterilization of males and females is an attractive alternative for elephant population control. However, it has been shown by modelling that at least 75% of breeding females would have to rendered infertile for a period of >10 years to produce a significant drop in the population and that it might be more efficient to sterilize pre-breeding females. However, this is unlikely to be achievable with the drugs and technology presently available. An ideal contraceptive would be deliverable as a single dose in a dart fired from a helicopter. Treated animals or their breeding groups would have to be identifiable, the cost per animal would be moderately high (at around US$ 150) and there would be no economic return for the effort. Problems with social and behavioural changes in treated individuals may occur, as well as the major disturbance during the treatment programme.

Ultimately, it appears likely that a combination of culling and contraception, with the latter having more application after elephant numbers have been reduced significantly, would find greatest acceptability. Those opposed to culling might be less vocal if contraception was being used simultaneously, while critics of population reduction without an economic return would be satisfied that the cropping option was not being ignored.

Conclusions
The following conclusions are pertinent to Zimbabwe’s elephant overpopulation problem:

· The elephant population in Zimbabwe has now reached crisis proportions and large-scale die-offs are probably imminent and unavoidable.

· Severe impacts on the environment and bio-diversity will continue for some time, even if population-reduction measures could be initiated rapidly. However, the resources needed to implement effective control and subsequent monitoring are lacking.

· A combination of culling and some contraception or sterilization would probably be the best solution. Local opinion would favour culling alone but the arguments for this course are not generally supported internationally.


References
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