African Wildlife & Environment Issue 77 FINAL ISSUE

FAUNA, FLORA & WILDLIFE

Quartzite boulder country on the top of Mariepskop near Hoedspruit with Aloe arborescence in flower (Krantz aloe). In the surrounding vegetation there are many ericoid-leaves shrubs typical of many heathlands as well as Podocarpus latifolius trees (Upright yellowwood) festooned with the grey-coloured lichen Usnea barbata (Old man’s-beard) because of the high rainfall and frequent mist

that he had stumbled on a system where plant- available nutrients, and not climate, determine the vegetation cover - namely heathlands. Whoa now! Surely heathlands are those treeless Calluna vulgaris hills of Scotland (now Erica vulgaris ) and parts of Ireland? And most certainly they are. But what is poorly known and understood by almost all South African botanists, ecologists and rangeland managers is that right here in South Africa we have extensive heathlands of our own, only we just do not recognise them as such – the reason being that we are fixated on the heathlands of the northern hemisphere and not recognising that here in the southern hemisphere we have extensive heathlands of our own – many with a tree overstorey. Over time I have also learned from Michelle Henley of Elephants Alive , that breeding herds in Kruger generally favour alluvial sites that are some of the most nutrient rich landscapes in the park.

success. What Mike also discovered was that Greywing only occurred above 1,940 masl, while Redwing were not constrained by altitude. This restriction of distribution was because Greywing have a short gut and need a high-quality diet to thrive and the 1,940 contour coincided with the lower level of the basalt – nutrient rich volcanic soils. Below 1,940 the geology is Karoo sediments that are severely weathered and nutrient poor by comparison. His basic conclusion was that phosphate (P) was the key nutrient – and where P is limiting, productivity is minimal. He goes on to give other examples such as Red Grouse in Scotland and starving Wildebeest in an apparent sea of grass - where fire is a key ecological driver. And from then on Mike understood the role of nutrients, especially P, and how the recycling of these nutrients, either by fire of by wildlife, is critically important. But what he did not know is

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