The Elephants of Kruger National Park

By Ron Thomson

THERE IS NO RECORD OF ELEPHANTS being present in Kruger National Park, South Africa, at any time during the 19th century. They first put in an appearance in 1905 when ten elephants took up residence in the Letaba/Olifants River Junction area. These animals were thought to have escaped from elephant hunters in what is present-day Mozambique. From a very early period after the elephants’ arrival, it was noted that the new arrivals were causing serious damage to the game reserve’s habitats – serious enough to give the administration cause for concern.

In those days the Kruger National Park was still known as the Sabie Game Reserve and it was administered by James Douglas Hamilton in whose employ was a young botanist called Albert Viljoen. Acting on Douglas Hamiliton’ s instructions, in 1944 Viljoen demarcated multiple research plots in the Satara area.

These research plots were one hectare in size and Viljoen counted every single tree in every plot which had a canopy spread of 15 meters or more. On average each plot had 13 top- canopy trees growing inside its boundaries (i.e. per hectare). Viljoen called these big trees ‘top- canopy trees’. And every year he religiously re-counted their numbers in every study plot – anticipating an ever-increasing rate of damage by elephants.

He called the habitat type ‘mixed deciduous woodland. He had selected Satara for his study area because it comprised the best and most expansive example of deciduous woodland habitat in the game reserve as a whole. And mixed deciduous woodland was the most heavily fed upon by Kruger’s growing elephant population. It could be said, therefore, that the Satara area was representative of the game reserve’s most important and most expansive habitat type; and species-wise, it was the most important woody-plant food source, for elephants in the game reserve.

Contrary to what Viljoen expected, there was no permanent damage done to the top-canopy trees until 1965 – by which time a new generation of game ranger and research officer had taken over the reins of the park’s administration.

What did happen however, was that by 1959 the park’s elephants had eaten up all the specimens of Aloe marlotii in the game reserve’s middle Sabie Valley which effectively caused the total extinction of this succulent species in the game reserve. It was not until six years later, in 1965, that the first of Viljoen’s top-canopy trees was reported to have been damaged. In fact, that report recorded that by 1965, on average, Viljoen’s top canopy trees had been reduced to 9 trees per hectare.

This report caused something of a panic in the ranks of the Kruger National Park staff who pleaded for, and were granted, the right to start culling the now much enlarged elephant population. However, although it was determined that Kruger’s elephant population had increased to 7000 animals in 1965, nobody was prepared to hazard a guess at the elephant carrying capacity of the game reserve’s habitats.

The National Park’s Board Director of that time, Dr. Rocco Knobel, was unhappy about this lack of information; and he asked his research staff how they expected him to provide them with what amounted to an ideal elephant population size when nobody had bothered to calculate the sustainable elephant population carrying capacity. This was a serious omission in the research staff’s submissions.

Dr. Knobel and the Kruger park staff, however, arrived at a compromise. The Director was assured that the elephant population size in 1965, at 7000 animals, was correct. This number was derived from accurate arial helicopter counts. So he determined an acceptable interim elephant culling quota target of 7000. He reluctantly came to this conclusion by admitting that he knew 7000 elephants was too many for Kruger to carry, but, in the absence of a proper elephant carrying capacity figure, he would have to be satisfied with the figure of 7000 until one of his research staff could determine the game reserve’s real elephant carrying capacity. He determined that every year, for however long the culling program would continue, the elephants of Kruger should not be allowed to exceed 7000.

The first cull took place in 1967. And for the next 27 years the elephant population was reduced to 7000 every year. To clarify this statistic, at the end of every year, 7000 elephants remained alive after the cull for that year had been concluded.

Coinciding with the culling target, the numbers of trees in the Satara Top Canopy Tree Study were periodically counted also. The tree count progressed as follows: in 1973 – whilst the numbers of elephants were reduced to 7000, the number of trees per plot were reduced, on average, to 3 trees per hectare. In 1981 whilst the number of elephants was again reduced to 7000, the number of trees left standing in the Satara Tree Study area had been reduced, on average, to 1.5 trees per hectare. And by 1994, when the elephant culling program was finally terminated, there were no trees at all left standing in the Satara Top Canopy Tree Study area.

What does this series of events tell us? It tells us that 7000 elephants were far too many for the Kruger National Park to sustainably carry. That being the case, how can we determine an elephant number that represents the sustainable elephant carrying capacity for Kruger National Park? We are helped by recording the numbers of trees in the Satara Top Canopy Tree study area that survived along the way. Travelling back to 1944 we know that the average number of top-canopy trees surviving in the Satara Top Canopy Tree Study area every year was, on average, 13 trees per hectare. And we know that none of these trees were adversely affected by too many elephants until after 1959. So, throughout the period 1944 to 1959 the number of elephants living in Kruger National Park was ‘within’ the game reserves’ sustainable elephant carrying capacity.

We also know that in 1965 there were 7000 elephants living in Kruger National Park. But we are looking for a figure that equates to the numbers of elephants that were living in the national park in the middle 1950s. This was the last decade before serious damage to the top-canopy trees started to occur.

Another thing we know is that an incremental rate (annual breeding rate) of 7.2 percent doubles an elephant population number in a period of ten years. We also know that the Kruger scientists had recorded a consistent incremental rate of 7.5 percent, from autopsy results from the dissection of female elephants, throughout the culling era. That means the Kruger elephant population was more than capable of doubling its size every ten years.

Now, if we want to determine the size of an elephant population at any time during its growth pattern, all we need is its incremental rate. We know that the Kruger elephant population was 7000 in 1965. And we know that it was roughly doubling its number every ten years. And we were looking for the elephant population size in 1955. Now, we know that if an elephant population is doubling its numbers every ten years going forwards in time, to determine what its population size was ten years backwards in time, all we have to do is to halve its known current population size. And half of 7000 (the 1965 population figure) gives us the elephant population figure for 1955 (3500). And that tells us that 3500 (+/- 500) is the elephant carrying capacity for Kruger National Park.

Integrating this information into the Kruger elephant culling statistics, tells us that had Kruger’s elephant culling program been determined by a reduction in population size to 3500 (instead of 7000) the population objective would have been achieved.

But this didn’t happen. All culling stopped in 1994 and the population immediately started its numerical recovery. And the elephant damage that the Satara Trees endured from 1960 onwards spread into all the deciduous woodlands throughout the national park. This has caused a catastrophe of immense proportions because the elephants have destroyed all the big trees that the big eagles, vultures and ground hornbills used to use for breeding. This mis- management of Kruger’s elephants will result in the extinction of many large tree species and of the park’s large birds of prey – a process that has already begun.

In 1994, when the general public asked the Kruger scientists for their assessment of the total tree damage to the National Park’s woodlands during the culling era, they replied: ’95 percent’. Ten years later they replied to the same question: ‘More than 95%.’

The True Green Alliance (TGA), with financial help from South Africa’s new Sustainable Use Coalition NGO (SUCo), produced a You-Tube documentary on this wildlife mis-management program and we asked the staff at Skukuza, Kruger National Park’s head quarters, for constructive criticism on its content. Our request has been studiously ignored.

South Africans should be advised that, some time ago, SANParks was handed down a mandate from parliament which effectively passed on to SANParks the responsibility of maintaining species diversity in Kruger National Park. This mis-management example of the park’s elephant population has effectively negated this important mandate and it has placed many species of wild plants and wild animals on the slippery slope to extinction.

The True Green Alliance was hoping to enlist the support of SANParks and many ordinary South Africans including school children in the rehabilitation of the park’s woodlands by way of re-seeding. Such a program would be of immense proportions and would involve people from all walks of life. We cannot, however, do this on our own because we need at least the moral support of SANParks if such a program were to have any chance of success.