One thing is uniform to elephants everywhere. An annual incremental rate of 7.2 percent will cause elephant populations to double their numbers every 10 years.
But as the population groups increase, they begin to over-utilise the resources of their dry season habitats and that will cause the incremental rate to decline – which is something that is happening in Botswana. We cannot, and must not, therefore, be too stubborn about accepting or rejecting actual elephant population numbers – because, in the end, exactitude in this regard is not the issue.
What is important is the impact that an elephant population (no matter what its number) has on the dry season habitats that it occupies every year. This is a reflection of the size of the population relative to the sustainable elephant carrying capacity of its habitat.
NB: The elephants of Botswana have shown that they can roam away from water, each day of every six-months long dry season, for a distance of 25 kilometres during which ‘ranging’ they somehow find enough food to stay alive.
But in so doing so, they strip every vestige of food (all edible grass and browse) within that 25 kilometre range of their water supply.
So that 25 kilometre radius becomes a virtual food-desert for all the other game animals which share the elephants’ habitat during every dry season.
These lesser animals cannot walk 25 kilometres every day to find food. That is why, when the 2013 elephant count was made public, the Botswana government informed the world that “all other species” had declined by between 60 percent and 90 percent.
The elephants suffer too. At the height of every dry season, hundreds of elephant mothers with small babies at foot, suffer the consequences of this starvation regime.
They stop lactating and hundreds of starving baby elephants are abandoned because they cannot keep up with their mothers on their long daily treks.
These babies die of starvation, heat-fatigue or thirst, or they are killed and eaten by hyenas and lions.
And the general biological diversities of the affected national parks suffer immense losses of species of both plants and animals.
So, it would be a good idea for us to have at least “some idea” of the elephant carrying capacity of the Botswana dry season habitats. How do we come to determining that?
Well, if we can accept the fact that elephants can and do double their numbers every ten years going forwards; we can determine elephant population sizes at any time in the recent past by extrapolating backwards.
If we accept, for example, that there were some 60 000 elephants in northern Botswana in 1990; there must have been 30 000 in 1980; 15 000 in 1970; and 7 500 in 1960…. which was when the elephants started to demolish the Chobe riverine forest strip. 7 500, therefore, were too many elephants for Botswana in 1960. So, maybe 5 000 would be a good guess at the elephant carrying capacity for Botswana in 1960 – at which time the habitats were still reasonably healthy?
Today, by comparison, all the habitats in Botswana’s elephant sanctuaries have been trashed.