Elephants versus baobabs in our
Evidence is mounting that elephants are killing baobabs in our regional parks, and saplings are increasingly
Days before the 2022 dry season ended, Clive Stockil stood in front of a 1,000-year-old-plus baobab on the Runde River floodplain in Gonarezhou National Park, Zimbabwe.
A recipient of the inaugural Prince William Award for Conservation in Africa and founder of Chilo Gorge Safari Lodge, Stockil has lived in the area all his life. He knows individual trees.
This particular specimen was in flower, great bowls of pollen and nectar on offer to bats. It was also decked out in wire mesh fencing, wrapped firmly around its portly torso to a height of 3m from the ground – a low-fi method of elephant protection.
Yet the mesh was not enough. Stretching out around the giant baobab were long furrows in the sandy earth. A renegade elephant, denied access to the trunk, had spent considerable energy digging up and consuming its moist roots. Whether the giant tree would survive would have to be seen.
The strange, smooth bark of baobabs (Adansonia digitata) has long been eaten by elephant. People, too, have used its bark for rope, and eaten its vitamin C-filled fruit.
Baobabs have evolved to cope with such attention. Given time, the bark heals over and the baobab continues clocking up years on centuries-long timelines. Even roots can recover. Their great age, size and bulbous shape have made baobabs important heritage symbols, never mind keystone species in semi-arid ecosystems.
But in the past two decades, there is the sense that baobabs in national parks such as Mapungubwe, Gonarezhou, and to a certain extent Kruger, aren’t getting a break.
“The baobabs in [Gonarezhou] have been impacted by elephant for a long time,” says Simon Capon of the Gonarezhou Conservation Trust. “But we do feel that the impacts have increased in recent years, with many iconic baobabs ultimately felled by elephant.”
Bulls usually begin the process, stripping the bark and opening up the fibrous interior. Gouging out the pithy wood can then result in dramatic damage, such as holes that extend right through the tree. If enough damage is regularly inflicted, with little recovery time, the baobab can collapse in on itself – Stockil has seen cow herds come and feed on such fallen giants for a week.
As observational accounts of felled trees mount up, research is kicking in. Gonarezhou has about 11,000 elephant, or two animals per square kilometre. In 2016 they were more numerous than impala. The Makuleke Contractual Park in northern Kruger has seen elephant numbers rise since community members were forced off their land in 1969. Elephant density in the Makuleke area during the 2011 dry season was well over two elephant per square kilometre. And in Mapungubwe, park manager Mphadeni Nthangeni says pachyderm numbers, especially in certain areas, are high.
“Something is happening to our mature baobabs,” says Nthangeni. Elephant are ringbarking and gouging many, but he thinks “a more complex set of circumstances” is currently to blame. All the scientists spoken to for this article cited the need for more data that takes factors such as drought, security for elephant movement and water availability into account. No one thought high elephant numbers alone were causing the uptick in damage to trees – it’s more about why they’re utilising the trees so heavily.
Nthangeni also pointed to a dearth of young saplings in Mapungubwe.
“Where are the baby baobabs?” is a question Dr Sarah Venter of the Baobab Foundation has asked for some years. Goats and other livestock decimate them outside parks, and game consumes them in protected areas. Because baobabs are so long-lived, it’s hard for humans to know if this is a serious threat or just a blip in recruitment.
“If you live one-and-a-half millennia, you don’t need to be producing babies every second year,” says ecologist Dr Timothy O’Connor, who is helping Gonarezhou to set up research to understand the impact of elephants on the rest of the park’s biodiversity. “Baobab recruitment is episodic.” But he does say there should then be more evidence of various sizes of trees.
A 2020 study produced by SANParks Scientific Services reassessed data collected from 501 mature baobabs in Mapungubwe between 2005 and 2009. By 2020, eight percent of the trees had died. Severe debarking by elephant had increased dramatically, with the majority of trees 76% to 100% debarked.
Dr Corli Wigley-Coetsee, a SANParks Savanna and Grassland Research Unit ecologist, agrees that elephant impact on Mapungubwe’s baobab has increased, with estimates of 8% to 10% mortality over 15 years. It’s not just baobab: more preferred species, including kanniedood trees (Commiphora), have largely disappeared. “Baobab may be next on the menu in terms of palatability,” she says.
Wigley-Coetsee believes that Kruger’s baobabs are in better shape. There are multiple reasons: Kruger’s landscape is larger and less linear, with more rugged areas, located further away from water. Such places provide “spatial refugia” for mature baobabs and even saplings. Large specimens on favoured elephant routes close to water, however, can be severely damaged. To help monitor change in the future, field rangers will use apps on handheld devices to capture data on the trees’ health.
Wigley-Coetsee, Stockil and O’Connor all say that in good times, baobab should be low on elephant menus. They prefer and need grass, then will choose to browse on foliage, and turn to debarking when better food is depleted. Mapungubwe has seen incursions of cattle from across the Limpopo, which might be contributing to less grass for elephants. Water abstraction from mines and agriculture outside Mapungubwe could also be impacting the water table and quality to the detriment of the ecosystem.