THIS FEATURE IS FROM VELD & FLORA MARCH ISSUE 109 (1), PAGES 8-11

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Circle of life

Take a journey with Bruce McKenzie to discover how plants deal with nature’s loadshedding and why size and shape matter in life’s energy flow

Mar 22, 2023 | WRITTEN AND PHOTOGRAPHS BY BRUCE MCKENZIE

Above: Sunset – the time when plants and animals prepare for another night of nature’s own loadshedding, remarks botanist, ecologist and author Bruce McKenzie.

ON THE DRIER, INLAND PLAINS to the East of southern Africa are where botanist and ecologist Dr Bruce McKenzie (71) has found time and space for relaxation and introspection for most of his life. Time and space in which he also enjoys pondering the network of many different ecosystems that shape the life of the bushveld.

Now BotSoc’s former CEO (1997-2008) has crystallised that pondering in his intriguing 195-page book, An Ecological Guide to the Bush (Jacana, R235). It is his answer to the many people who have asked him to provide them with some ecological understanding of the bushveld and crystallises his evolving thinking over 40 years of lecturing on ecosystems at the University of the Transkei (now Walter Sisulu University), University of the Western Cape and Cape Peninsula of Technology.

“I wanted to pass on information and insights that I had gathered about the bushveld and what makes it tick in a format that is readable, less scientific and novel,” he recalls. “Covid 19 provided me with the space to concentrate on this challenge and the book took about two years to complete.

Above: Bruce McKenzie has made a point of experiencing the bush and learning from local people – in this case in Botswana.

DUST TO DUST

“Scientifically, I changed my focus over the years from concentrating mainly on identifying different species to including the function of plants and animals as well. Lecturing, interacting with students and discussions in the field with peers and friends gave me the opportunity to consider how energy flows through the different feeding, or trophic, levels.”

Plants have a premium position in this energy cycle, growing by absorbing nutrients from the earth and being eaten by herbivores and browsers of all sizes, which in turn become the prey of carnivores. Dung then enriches the soil and eventually, whether plant, plant-eater or carnivore, their decaying bodies become the food of decomposers, also enriching the soil for another generation.

Using examples of species that you might commonly see in the bushveld, from larger mammals to insects and tiny reptiles, Bruce explains how the food that a species uses for fuel can control its size, shape, digestive system type – even how many stomachs a mammal might have. In an eye-opening way, he shows how all this relates to how much energy these creatures need to function and control their body temperature.

Above: The world’s tallest herbivore takes a pause from browsing.

Above: Sociable weaver nests are a great example of interdependence in the bush.

ROAMING THE VELD

Bruce grew up on a livestock farm outside Kimberley where roaming the veld nurtured his interest in plants and animals.

“As youngsters, my cousin Simon and I tried to hunt birds and small mammals with catapults,” he recalls. “In our teens, we hunted springbok on bushveld properties within about a 100-kilometre radius but in our early twenties, we both stopped hunting and concentrated on visiting larger game parks throughout South Africa, Namibia and Botswana.”

Bruce moved to Cape Town for university studies and he and his family have been based there for most of the time since. Even so the bushveld still calls him regularly.

Above: Bruce McKenzie (centre with beard) exchanges information with citizen scientists.

“I really enjoy drier bushveld places such as the Kalahari and Namibia because the biology there often has interesting examples of extremes in terms of heat and dryness. Among the moister areas, my favourite is Savuti in Botswana because I feel you are really in the natural world of the African savanna with its immense animal and plant diversity – true safari country.”

Bruce has travelled briefly to game parks in east Africa and would love to go back to spend a month or two. He also hopes to make a return trip to see the gorillas in Rwanda. Writing the book has also shown him that the lecturing life still has a pull for him.

“I would love to be a short-term guest lecturer at some wildlife educational unit anywhere in the bushveld,” he says.