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05 June 2018 Photo Supplied
Digging up truth South Africa was way different to what you thought
Archaeological excavations in the Wonderwerk Cave, north of Kuruman in the Northern Cape.

Research fellow Dr Lloyd Rossouw from the Department of Plant Sciences at the University of the Free State (UFS) recently published an article in the Nature Ecology and Evolution journal with Dr Michaela Ecker from the University of Toronto as lead author, and Dr James Brink, research fellow at the UFS Centre for Environmental Management. The findings described in “The palaeoecological context of the Oldowan-Acheulean in southern Africa” provides the first extensive paleoenvironmental sequence for the interior of southern Africa by applying a combination of methods for environmental reconstruction at Wonderwerk Cave, which have yielded multiple evidence of early human occupation dating back almost two million years ago.

Where water once was
The Wonderwerk Cave is found north of the Kuruman hills (situated in Northern Cape) a 140m long tube with a low ceiling. The surroundings are harsh. Semi-arid conditions allow for the survival of only hardy bushes, trees, and grasses. But during the Early Pleistocene, stepping out of the Wonderwerk Cave you would have been greeted by a completely different site, the researchers found. Using carbon and oxygen stable isotope analysis on the teeth of herbivores (Dr Ecker), fossil faunal abundance (Dr Brink), as well as the analysis of microscopic plant silica remains (phytoliths) excavated from fossil soils inside the cave (Dr Rossouw), the results show that ancient environments in the central interior of southern Africa were significantly wetter and housed a plant community unlike any other in the modern African savanna. 

What difference does it make?
While East African research shows increasing aridity and the spread of summer-rainfall grasslands more than a million years ago, the results from this study indicate an interesting twist. During the same period, shifts in rainfall seasonality allowed for alternating summer and winter-rainfall grass occurrences coupled with prolonged wetlands, that remained major components of Early Pleistocene (more or less the period between one and two million years ago) environments in the central interior of southern Africa. That means our human ancestors were also living and evolving in environments other than the generally accepted open, arid grassland model.

News Archive

Fire as a management tool questionable in arid and semi-arid grassland areas
2015-03-24

Wild fire in the grassland
Photo: Supplied


The influence of fire on the ecosystem in the higher rainfall ‘‘sour’’ grassland areas of southern Africa has been well established. However, less information is available for arid and semi-arid ‘‘sweet’’ grassland areas, says Prof Hennie Snyman, Professor in the Department of Animal, Wildlife, and Grassland Sciences, about his research on the short-term impact of fire on the productivity of grasslands in semi-arid areas.

Sour and sweet grassland areas can be defined as receiving either higher or lower than approximately 600 mm of rainfall respectively. In quantifying the short-term impact of fire on the productivity of grasslands in semi-arid areas, a South African case study (experimental plot data) was investigated.

“Burned grassland can take at least two full growing seasons to recover in terms of above- and below-ground plant production and of water-use efficiency (WUE). The initial advantage in quality (crude protein) accompanying fire does not neutralise the reduction in half of the above-ground production and poor WUE occurring in the first season following the fire.

“The below-ground growth is more sensitive to burning than above-ground growth. Seasonal above-ground production loss to fire, which is a function of the amount and distribution of rainfall, can vary between 238 and 444 kg ha -1 for semi-arid grasslands. The importance of correct timing in the utilisation of burned semi-arid grassland, with respect to sustained high production, cannot be overemphasised,” said Prof Snyman.

In arid and semi-arid grassland areas, fire as a management tool is questionable if there is no specific purpose for it, as it can increase ecological and financial risk management in the short term.

Prof Snyman said: “More research is needed to quantify the impact of runaway fires on both productivity and soil properties, in terms of different seasonal climatic variations. The information to date may already serve as valuable guidelines regarding grassland productivity losses in semi-arid areas. These results can also provide a guideline in claims arising from unforeseen fires, in which thousands of rands can be involved, and which are often based on unscientific evidence.”

For more information or enquiries contact news@ufs.ac.za

 

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