Ecosystem

The Reserve

A brief description of the Djuma environment

Djuma is situated in the Lowveld Savanna in the northeastern part of South Africa. The Lowveld Savanna stretches from the Drakensberg Mountains towards the Mozambican flood plains and coast. The soils are ancient eroded granite derived from the Granite / Gneiss bedrock. The undulating bedrock is reflected in the landscape and the vegetation in turn has distinct zones as a result. The plant communities follow the contour lines and are divided into three distinct plant communities: the footslope and drainage line zone, the midslope seepline and the crest or uplands zone.

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The reason for these distinct plant communities is due to the distribution coarser and finer soils along the slopes. Movement of soil particles and nutrients over time has separated the soils into sandy, relatively nutrient poor soils in the uplands or crest and finer soil particles and nutrients have accumulated at the footslope and drainage line. Since the granite bedrock is impervious to water, any rain water seeping through the sandy crest eventually seeps to the surface of the land where the sandy and clayey horizons meet, that is midslope. Refer to the diagram.

In summer this seepline becomes waterlogged and since most trees are unable to grow in waterlogged conditions, grasses are dominant in this midslope seepline. Just above the seepline, the Silver cluster-leaf (Terminalia sericea) grows, almost in a straight line along the sandy / clayey horizon. The crest plant community is the largest in the sense that it occupies the greatest percentage of the land surface. "Mixed grass" and trees such as the Marula (Sclerocarya birrea) and the various bushwillow (Combretum sp.) species characterize it. Mixed grass refers to a swath that includes both sweet grass as well as sour grass species, sweet grass refers to grass that retains its nutritional value even when it is dry in the winter months whereas sour grass loses its nutritional value when it dries.

These upland or crest trees are characterized by large unprotected leaves, i.e. as a rule no thorns on these species. The reason for this is that since these plants grow on relatively poor soils their leaves are not nutritious and are thus not sought after by browsers. That is, the trees do not have any need to protect their leaves.

The footslope and the drainage line has relatively rich soils and here the trees are protected from browsers, some are poisonous such as the Tamboti (Spirostachys africana) and others have small leaves and large thorns such as for example the acacias (Acacia sp.) and buffalo thorns (Ziziphus mucronata). This plant community is continuously under attack from browsers because the leaves are nutritious.

So when you drive through the Djuma landscape look for the patterns in the plant communities. Large leafed tree species with no thorns on the crest or uplands, the Silver cluster leaf fringe above the seepline and the mostly grassy seepline midslope. Finally, at the bottom of the slope, in the footslope and drainage, most tree species are thorny, small leafed or even poisonous.

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Djuma Game Reserve

P. O. Box 338, Hluvukani, 1363, Mpumalanga, South Africa

Tel: (+ 27 13) 735 5118

Fax: (+ 27 13) 735 5070