There were no elephants in Kruger National Park until 1905. Then ten elephants pitched up (from Mozambique) and took up residence in the Olifants/Letaba river junction area. This was the only immigration group ever recorded. But there MUST have been more if we are to account for the rapid increase in elephant numbers after 1905.
By the 1940s Mr James Stevenson Hamilton (Snr Game Warden) and Albert Viljoen (Botanist), recognized a rise in elephant numbers and a corresponding damage to ever more numbers of large trees in the park. And in 1944 Viljoen set about demarcating large numbers of one-hectare research plots in the Satara area of the park – and the location, the species and the numbers of every tree with a canopy spread of 15 meters of more, was recorded, measured and mapped in every one of the research sample plots. The result: the average number of these (what Viljoen called “top canopy trees”) in these research plots was 13 trees per hectare.”
The Satara area was selected for this experiment because Viljoen believe that its deciduous woodland properties were a good reflection of the deciduous woodlands growing elsewhere throughout the national park. At first the trees were checked annually for tree damage.
What became known as the Satara Top Canopy Tree Study then began in earnest.
No damage to the Satara trees was recorded for the next sixteen years (and more). In 1959, however, elephants were recorded as having been responsible for the extinction of the succulent plant Aloe marlothii in the Sabi River area.
No Satara trees were recorded as having been damaged by elephant until AFTER 1960. But I have a suspicion there was a lapse in the counting process because, in 1965, the scientific staff at Skukuza were suddenly made aware of the fact that the Satara Top Canopy Trees had be reduced in number to, on average, 9 trees per hectare. This caused something of a panic in the scientific community. They called for a meeting at Skukuza with the South African National Parks Board Director, Dr Rocco Knobel – who was told the sad news when he pitched up at Skukuza for the planned meeting. The South African National Parks Board is now called SANParks.
The first thing Dr. Knobel asked was: How many elephants have you got in the national park? He was told 7000.
The next thing Dr Knobel asked was: What is the elephant carrying capacity of the Kruger National Park (KNP) habitats? Nobody could tell him. And nobody knew how to determine a quick answer to that question.
The scientific staff then requested of Dr. Knobel that they institute a culling operation in the national park. And they used the damage to the Satara Top Canopy Trees as justification for that request. They stated that the damage to the trees clearly indicated there were too many elephants in the national park. But they could not tell Dr Knobel “how many” were “too many”.,
In the absence of any further useful information, Dr Knobel agreed to the requested elephant culling programme but, because he had had no definitive answer to his elephant carrying capacity question, he agreed only that the elephant population should not be allowed in increase beyond the population’s current number (7000). And he said that he would consider a different culling target if (or when) his scientists advised him about the elephant habitat carrying capacity number (which he said was an imperative statistic for that purpose). And it most certainly is that.
It took the staff at Kruger two years to construct an abattoir that was big enough to process the numbers of elephant carcasses they expected to handle. During those two years the whole culling situation at Skukuza remained inoperative.
Culling commenced in 1967 by which time the elephants had reduced the Satara Top Canopy Trees from 9 per hectare (which was the count in 1965) to 6 per hectare in 1967. But from 1967 onwards the elephant population of Kruger National Park was annually reduced to 7000 animals.
Nobody (apparently) ever tried to provide Dr Kobel with an elephant habitat carrying capacity number. So, the Skukuza staff carried on with the culling programme reducing each annual population number down to 7000 every year for the next 27 years.
In 1974 the Satara trees were again counted. They had by then been reduced, on average, to just 3 trees per hectare.
In 1981 the Satara trees were again counted. And it was found that their number had been reduced, on average, to just 1,5 trees per hectare.
In 1994 the culling operation was concluded by which time there were no Satara trees left standing in any of the survey plots. And the Skukuza scientists stated, quite blandly, that since 1960 they estimated that the total number of top canopy trees, throughout the Kruger National Park, had been reduced by 95 percent (caused by too many elephants). A few years later they stated that the park’s top canopy trees had been reduced (by too many elephants) by more than 95%. And that is the statistic that still applies at this time. Why the culling was stopped is not clear. It has been suggested, however, that the culling was stopped because it did not stop the tree damage by elephants. After the last cull was over, the elephant population of Kruger National Park stood at a proven 7000.
A lot of biological information, however, was garnered by the Kruger scientists from the autopsies conducted on every dead elephant carcass recovered throughout the 27 years of the culling operation. One of the most important pieces of information – as far as I am concerned – is that throughout the culling operations the elephants of Kruger National Park consistently maintained an annual increment level of 7.5 percent. This is critically important information because it led to me accurately determining the elephant habitat carrying capacity figure for Kruger National Park – which is something that nobody else in the world has ever been able to do. And it was so simple!
Any animal population (including elephants) that has an incremental level of 7.2 percent is capable of doubling its numbers every ten years. So, a consistent incremental level of 7.5 percent means that the breeding rate of the Kruger elephants, throughout the twenty-seven years of the culling era, was easily capable of doubling its numbers every ten years. And I ask you to accept that 7.5 percent is only marginally greater than 7.2 percent – and 7.5 is slightly “better” because it is on the positive side of the scale. So, for the purposes of this exercise, I am going to accept that the Kruger elephants HAD a doubling time of ten years (and I am going to ignore the minor difference).
To keep you ‘with me’, therefore, I am now going to define what elephant carrying capacity means.
ELEPHANT CARRYING CAPACITY IS THE MAXIUM NUMBER OF ELEPHANTS THAT A HABITAT (OR GAME RESERVE) CAN SUSTAINABLY CARRY (AND “SUSTAINABLY CARRY” MEANS “THE MAXIMUM NUMBER THAT DOES NOT PERMANENTLY DAMAGE THE HABITAT”)
Now let’s understand that the KNP elephant population was maintained at the number 7000 by the annually culling-and-removal of all elephant numbers in excess of 7000. So when we consider the next series of arguments we have to accept that we are dealing here with a population that effectively numbers a static 7000 animals.
Now! How do we assess this number? Is 7000 the elephant carrying capacity figure for KNP? No, it is not! How do we know it is not? Because throughout the culling era the Satara trees continued to suffer permanent damage (check out the definition!) until no trees were left standing:
- 1965 – 7000 elephants – trees were reduced in number (between 1960 and 1965) from 13 trees per hectare to 9 trees per hectare;
- 1967 – 7000 elephants – trees were reduced in number (between 1966 and 1967) from 9 trees per hectare to 6 trees per hectare.
- 1974 – 7000 elephants – trees were reduced in number (between 1968, 69, 70, 71, 72, 73 & 74) from 6 trees per hectare to 3 trees per hectare;
- 1981 – 7000 elephants – trees were reduced in number (between 1975, 76, 77, 78, 79, 80 & 81) from 3 trees per hectare to 1.5 trees per hectare;
- 1994 – 7000 elephants – trees were reduced in number (between 1982, 83, 84, 85, 86, 87,88, 89, 90, 91, 92, 93, 94) from 5 trees per hectare to NO TREE LEFT STANDING.
So, what are we looking for? We want a time in the KNP’s history when we know that the elephants were not causing severe and permanent damage to the habitat; and we want to know how many elephants there were in KNP at that time. When was that time? It was certainly prior to 1960 because it was at ‘about’ 1960 that the elephants started to damage the Satara trees in a big way – but not, apparently, before 1960. It would appear, however, that no damage had occurred to the Satara trees by 1959 (When the Aloe marlothii was exterminated). So, it would be fair to say that we want to know how many elephants there were in KNP in, say, 1955 (The middle 1950s). And it just so happens we can determine those numbers quite easily. We have indicated that an elephant population with an annual increment of 7.2 percent doubles its numbers every ten years. We also know that throughout the culling era the Kruger elephants were reproducing at 7.5 percent (little different to 7.2 percent). We can also say, therefore, that because such an elephant population doubles its numbers (going forward in time) we can also determine how many elephants comprised the population ten years previously – simply by halving the current number. And we know that Kruger’s elephant population stood at 7000 in 1965. So – calculating backwards in time – we can find out how many elephants there were in 1955 simply by halving the 1965 population figure (7000). And that number comes to 3500.
So, my guess is that 3500 +/- 500 is the nearest anybody is ever likely get at determining the elephant habitat carrying capacity for Kruger National Park when the habitats were still healthy.
Going forwards in time from 1994 onwards, we can also calculate the KNP elephant population simply by doubling its standing population every ten years:
- 1994 – 7000.
- 2004 – 14000
- 2014 – 28 000
- 2024 – 56 000 (projected beyond 2022)
The Kruger Scientists after years of fudging the truth have finally admitted to an elephant population of 31 527 – but it is not clear how they came by this figure. As far as I know there have been no aerial elephant counts done in Kruger National Park since 1994. If I was to hazard a guess, however, I would say the real Kruger elephant population figure in hovering around 50 000 at this time.
Whatever the real population might be, however, to “do the right thing for the park’s biological diversity” Kruger needs to remove several tens of thousands of elephants to bring the population down to 3500. This is an acid test that still has to come.
Next, no doubt, will come the question of rehabilitating the old elephant-destroyed habitats where all the vegetation has been utterly destroyed!
Ron Thomson CEO -True Green Alliance of South Africa.