Mmegi (Botswana)

A crisis of too many, not too few (Part 2) 

There are now at least 130,000 elephants in Botswana, which is part of approximately 216,000 elephants in the Kavango Zambezi TFCA and the largest elephant population in Africa.

By CORRESPONDENT Fri 03 May 2019, )

However, elephant poaching in the rest of Africa does not imply that southern Africa should accept a massive and destructive over-population of elephants. Like any excesses – too many elk in Yellowstone, too many cattle on the range – this has visible and less visible environmental and human consequences.

In Botswana’s case, these are magnified by poverty and the fragile complexity of dry savannas. Forests of dead and dying trees are visible for all to see, but elephants are also causing massive changes in the composition and function of these ecosystems that are less visible to the casual observer.

If you enter Chobe National Park along the original road from Kasane town, you will pass a small ruined house on the banks of the Chobe River near the old park gate. This was built by my father in 1965. It replaced the tent where my mother and I lived while my father spent many weeks deep in the field mapping and measuring the environment before the days even of reliable radios, let alone maps and satellite images.

Set amongst huge riverine trees, this ‘house’ overlooked the dense reed beds of the Chobe floodplain. We could not see the cars on the nearby road because the riverine bush was so thick. Today, the extensive reedbeds are gone, and there is no longer any thick bush to hide the ruins of our old house, one small symptom of the radical alterations to Botswana’s ecosystem since the 1960s wrought by tens of thousands of elephants.

My late father, as Botswana’s first professional ecologist, played a significant role in shaping Chobe and other national parks, as well as creating Botswana’s Department of Wildlife and National Parks.

Indeed, the agency logo is a bat-eared fox, the legacy of our pet Nipper rescued from a python in the Kalahari. My father was mentored by Thane Riney, who led FAO’s Africa Special Project for wildlife and later played a prominent role in IUCN. With powers of observation that I always found miraculous, my father had an exceptional capability for ‘reading’ the environment, while scrupulous observation about the number and condition of animals, grass, and trees fill his worn notebooks and carefully cross-referenced forms. This is how we know that, in 1965, 299 trees lined a mile-long river transect from our camp, including 17 species of big, impressive giants.

One of my greatest pleasures as a new professor at the University of Florida in 2004 were the many months I spent with my students and my father as he unwrapped the ecological and human history of northern Botswana and eastern Namibia for us, and as we redid some of his measurements.

It is not good enough to be appalled by the devastated riverine habitats in Chobe. To quantify these losses we recounted these trees and repeated some of his early transects. Much to our surprise, there were now slightly more trees – 324 to be exact. However, the structure of the habitats had been transformed, and not in a good way. Fully 270 (83%) of the ‘trees’ along the Chobe riverbank were the scrubby bush Croton megalobotrus. Huge knob thorns (Acacia nigrescens) that had constituted 51% of the forest were now down to 1.3 percent – indeed, only four of the 152 large had survived. Six slow growing large species disappeared altogether.

The only ‘real trees’ to survive are the unpalatable Natal mahoganies (Tricelia emetica). Six of the 14 species recorded in 1965 disappeared, including Ziziphus micronata, Diosyrus mespliformis, Kigelia africana (pinata), Acacia albida, Acacia galpinii and Acacia erioloba.

Many of these are big, impressive (and palatable) trees. Three species not previously present have colonized the strip, Markhamia obtusfolia, Markamia zanzibarica and Capparis tomentosa, which is actaully a vine that grows into the tree layer and can be self-supporting.

Despite the obvious damage and obvious cause – too many elephants –, more than one politically correct scientist has sought fascinating explanations to shift the blame away from elephants and to avoid the need to tackle a looming problem.

One would expect these radical changes in vegetation to be transmitted to the animal kingdom through the intricate hand of ecological feedback mechanisms. Repeating my dad’s transects and dung plots from the 1960s showed that this was the case, with a radical shift in the composition of wildlife diversity. Increaser species like elephant, impala and kudu respond positively to shrub encroachment and were doing well, as were giraffe which, historically, never occurred on the riverfront.

However, ecology is a story of winners and losers. There were substantial declines in warthog and waterbuck, and we no longer counted a single example of the bushbuck, puku and wildebeest of yesterday in the sample plots. Ironically, the Chobe bushbuck is now rare in Chobe, except near human habitation where thickets are protected from elephants.

With too few samples to be statistically sure, we nevertheless express concern about declines in rare antelope like tsessebe, while and perhaps roan and sable, were perhaps also less common at lower numbers. This places great responsibility and poses tough decisions for those of us who claim to promote healthy ecosystems, or praise the mantra of biological diversity.

In 1968, my father expressed his concern that elephants were damaging the health of the ecosystem to higher authorities. At this time, there may have been as few as 15,000 elephants in Botswana, and surface water was more abundant.

He documented a widespread tendency for elephant to concentrate on particular species of trees in given areas, often destroying them in a short period of time.

The majority of mukwa and mugongo nut trees were ring barked in an area just to the north of Ngwezumba Bridge in 1963.  Virtually all the Kirkia and Commiphora trees were pushed over in a large area on the face of the sand ridge west of Ihaha in 1965.

All but one of the 124 lone Acacia tortilis trees scattered through the mopane woodland in the eastern Mababe had been pushed over by elephant that year. Many of the old majestic camel thorn trees, Acacia erealoba, around the Savuti channel and to the south of the Gubatsa hills were also killed by elephant in that or the next year.  Returning to Kasane in 2007, he wrote: “The once magnificent riparian strip with its attendant species of birds and small animals has all but disappeared except where it is protected by the old Park Headquarters, and even there it is under threat. When we left Kasane there was a magnificent belt of mainly camel thorn trees (Acacia erioloba) running up the length of the Sedudu valley where Selous camped in 1874, but elephant had already started work on them. Today virtually all of the 600 odd trees that had been over 400 years old stand as stark skeletons in a sea of scrubby croton bushes.”

Was this an isolated problem, limited to the Chobe riverfront? My father and Tim Fullman, my PhD student, bounced 80km south of the river on old cutlines to count trees and tree damage, complaining bitterly about having to cross the “haemorrhagic plains” of the upper Ngwezumba catchment, once a permanent source of water and home to a band of bushmen. It is hard to be scientific about what is not there, but many of the palatable species that one would expect in these environments were ‘missing’ from Tim’s data. We saw the same thing in Moremi, when my father trained my students in ecological methods by repeating his old transects. In a transect near the Khwai community, tasty species like Ziziphus macronata and good old knob thorns recorded on my father’s 1967 transect forms were gone, or stood as stark skeletons.

The elephants had eaten all the sweets in the shop. They also seemed to be ‘farming’ mopane, which was spreading because of its ability to coppice when knocked down. Indeed, 70% of the huge mopane trees near Third Bridge were gone, often lying supine and sprouting brush.

My father said this was perhaps the most magnificent stand of cathedral mopane he had seen – likening them to the old oak forests of Europe in his notebooks.  As had happened in Chobe several decades before, almost every Acacia nigrescens that we passed was dead or damaged as elephant populations pushed ever deeper into the Okavango delta.

People may not worry too much about mere plants if the alternative is to deal with the elephant ‘problem.’ But with elephants constituting 92% of the large mammal biomass in Chobe by 2011, this imposes costs in terms of the other animals and the loss of palatable species and habitats.

Tsessebe are far rarer than elephants, but used to be the favoured species for bush rations by scientists like my father, because they were numerous in Chobe and Moremi. He measured every one he shot and, writing a detailed paper about them claimed, with a grin, that he was a world expert – on tssesebe. Tssesebe thrive in ecotones, between the woodlands and the grasslands.

Elephants destroy these edges through tree destruction and shrub encroachment. With these sharp ecotones between woodlands and grasslands now largely gone, so therefore are the tssesebe.

Always learning from local people and history, my father put together a history of the elephants in Botswana, which I have summarised from his memoirs. Before 1912, A. G. Stigand, District Commissioner, explored and mapped Ngamiland District extensively for 10 years. He stated categorically that there were then no elephant or buffalo in the area.

Chobe District also had very few elephants. Several early hunters recorded their explorations in northern Botswana. In 1853, Chapman found about 250 elephant near the Shinamba hills in the south east of what is now the Chobe National Park, but he found no elephants north of this all the way to the Linyanti River.

Courtney Selous hunted and explored the south bank of the Chobe in 1874. Along the entire Chobe riverfront between Kasane and Ngoma, he found about a hundred elephant, shooting a number of them.

Elephants were uncommon

This does not imply that there were no elephants in north eastern Botswana and the eastern Caprivi prior to the mid-1940s, comprising a few as they were certainly know there before then, but apparently only in small scattered herds.

Nonetheless, elephant were uncommon, and the ecology was arguably a lot healthier than it is today. My father tracked down and interviewed several elderly Bushmen who had grown up around the source of the Ngwezuma River, which is now in the centre of the park. According to them, elephant were unknown to the Bushmen living in the east of the Chobe Game Reserve for several generations, at least until the mid-1940s.  Then, the “country filled with elephant” in a single year.

By 1963, Pat Hepburn, the park warden and our neighbour in Kasane, counted an average 497 sets of tracks along the ‘main’ Chobe road each day in 1963. This increased to 619 by 1966, an increase of at least 20% although 1966 was a wet year when many of the pans held water late into the dry season and elephants did not need to move to the river.

Well-used elephant paths now linked Wankie (Hwange) National Park to Chobe, as the rapidly growing elephant population in Hwange spilled over into Botswana.

In the early 1930s, when the warden of Hwange, Ted Davidson, started pumping water for elephants in the early 1030s, he estimated there were 2,000 elephants. However, Zimbabwe’s elephant population exploded from only 4,000 in 1900 to over 76,000 by 1991. Culling some 46,775 animals to save the vegetation caused only a minor blip in the inexorable increase in elephant numbers and the accompanying habitat destruction.

The Chobe-Hwange elephant population now numbers some 200,000-250,000 animals, and has spread into Namibia, Angola and western Zambia. Interestingly, this was not the primary elephant population in the early and mid-20th century, which were a different sub population, centred on the Tuli Block and the Limpopo River, in what was then called the ‘Tati Concession.’

This land on the borderlands of the Bechuanaland Protectorate near Francistown, was granted to Sir John Swinburne by the Ndebele King Lobengula in the late 19th century, in the region of Francistown, and was incorporated into Botswana in 1911.

In good rainfall years, elephants were seen and reported along the northern fringe of the Makgadikgadi Salt Pans, apparently travelling west to Lake Ngami and north to the Shinamba hills. The Bechuanaland authorities set up a special unit to eliminate the survivors in the late 1950s or early 1960s.

In an irony shared with many countries in Africa, Botswana’s Elephant Control Unit, run by Pat Bromfield and John Benn, evolved into the Game Department and finally today’s Department of Wildlife and National Parks.

My father was employed by the FAO Africa Special Project to plan and map Chobe and northern Botswana, and to create this new department, together with the former chief game warden of Uganda, Lawrence Tennant, and my father’s good friend Alec Campbell the anthropologist.

In 1963, his FAO boss, Dr Thane Riney, who was establishing projects all over Africa, described the wildebeest, zebra, gemsbok and springbok around western Makgadikgadi Pans as ‘the largest herds of plains game left in Africa today,’ the Serengeti notwithstanding.

My father’s interviews with old residents of Botswana, both black and white, often mention springbok treks. A number of authors from the late 19th and early 20th Century in South Africa describe hundreds of thousands of springbok swarming for hundreds of miles, consuming all the vegetation in their path.

Conwright-Schreiner, who wrote one of the most authentic accounts of the treks in 1925, observed 50, 000 springbok using binoculars from a single point in a trek that covered 130 by 15 miles.

Davis (1921) describes ‘100 million head’ from part of a trek through which he drove for 47 miles, and where the shooting of thousands of animals did not seem to reduce their number.  The 1950 trek took place on a front of at least 200 miles and took three days to pass Tshabong.

The truly spectacular springbok migrations are not the only Botswana phenomenon that has passed into the realms of history.

My father’s memoirs offer a glimpse into Botswana’s wildlife as it used to be. Having also worked in Egypt and Saudi Arabia, he was at pains to emphasise that the well-grassed Kalahari was the last ‘natural’ desert in the world, with regular sightings of springbok, gemsbok, hartebeest, and less frequently, eland. This was interspersed with occasional but vast herds of mobile antelope, mainly wildebeest or hartebeest, probably exceeding 100,000 head.

At least a quarter of a million wildebeest were recorded on the open grassland around the Makgadikgadi pans from the mid-1930s to the late 1950s, until the population crashed between 1962 and 1965.

Waking up in his tent on the Makgadigadi after a spectacular rainstorm, my father recalled one of the most spectacular scenes of his life – in the crystal clean air, his tent was surrounded by over 25,000 wildebeest and zebra, 1,000 springbok, a handful of hartebeest and one hyaena.  As we discuss the future of Botswana’s wildlife industry, it does us well to remember that what we see today, spectacular as it can be, is but a ragged remnant of the pulsing wilderness and extravagant wildlife phenomena that my father enjoyed but sixty years ago.

*Dr Brian Child is an Associate Professor at the University of Florida where he focuses on wildlife economy and governance, and higher education in African leadership development. With a D.Phil from Oxford about the economics of wildlife and livestock, he grew up in Botswana, served private landholders and the CAMPFIRE programme for Zimbabwe Parks for 12 years, and established CBNRM and park management systems in Zambia for 10 years. His current interest is building a $ 30 billion wildlife economy in southern Africa by 2020.

This is the second part of a serialised article made available exclusively to Mmegi.