18. MIXED BUSHVELD

Synonyms:

Mixed Bushveld (A18), Sourish Mixed Bushveld (A19); Broad-orthophyll Plains Bushveld.

Statistics:

66 647 km²; ± 60% transformed; 3.05% conserved.

Locality & Physical Geography:

This bushveld represents a great variety of plant communities, with many variations and transitions. The vegetation varies from a dense, short bushveld to a rather open tree savanna, covering the greater part of Northern Province and the northern parts of North-West Province. The area comprises mostly undulating to flat plains at an altitude of 700 to 1 100 m.

Climate:

The rainfall varies between 350 to 650 mm, occurring in summer. Temperatures range from -8C to 40C, with an average of 21C.

Geology & Soil:

The soil is mostly coarse, sandy and shallow, overlying granite, quartzite, sandstone or shale.

Vegetation:

The vegetation varies from a dense, short bushveld to a rather open tree savanna. On shallow soils Red Bushwillow Combretum apiculatum dominates the vegetation. Other trees and shrubs include Common Hook-thorn Acacia caffra, Sicklebush Dichrostachys cinerea, Live-long, Lannea discolor, Sclerocarya birrea and various Grewia species. Here the grazing is sweet, and the herbaceous layer is dominated by grasses such as Fingergrass Digitaria eriantha, Kalahari Sand Quick Schmidtia pappophoroides, Wool Grass Anthephora pubescens, Stipagrostis uniplumis, and various Aristida and Eragrostis species. On deeper and more sandy soils, Silver Clusterleaf Terminalia sericea becomes dominant, with Peeling Plane Ochna pulchra, Wild Raisin Grewia flava Peltophorum africanum and Burkea africana often prominent woody species, while Broom Grass Eragrostis pallens and Purple Spike Cat'stail Perotis patens are characteristically present in the scanty grass sward.

Key Environmental Parameters:

Fire and grazing determine the structure of this vegetation type.

Economic Uses:

Cattle and game farming, cultivated crops and ecotourism.

Conservation Status:

Conserved in various smaller provincial nature reserves, private game farms and conservation areas, such as Ben Alberts, Mabula, Vaalkop Dam, Rust der Winter Dam, Roodeplaat Dam, Loskop Dam, Nylsvley and Rustenburg, Pietersburg, Percy Fyfe and Ben Lavin Nature Reserves.

Key References:

Theron (1973), Coetzee (1975), Van der Meulen (1979), Van der Meulen & Westfall (1980), Van Rooyen (1984).

Authors:

Noel van Rooyen & George Bredenkamp.