41. Wet Cold Highveld Grassland

Synonyms:

Highland Sourveld (A44a); Rhus dentata-Leucosidea sericea Thicket.

Statistics:

9 502 km²; ± 60% transformed; 6,72% conserved.

Locality & Physical Geography:

This vegetation type is associated with rocky slopes and ravines of the lower slopes of the Drakensberg, at altitudes greater than 1 750 m.

Climate:

The rainfall is about 900 mm per year, occurring in summer. Temperatures vary between -5°C and 36°C, with an average of 16°C.

Geology & Soil:

Soils, typical of a mountain landscape, are shallow lithosols, mainly representative of the Glenrosa and Mispah soil

forms. Sandstones and mudstones of the Elliot and Molteno Formations (Karoo Sequence) and the Beaufort Group are predominant rock types.

Vegetation:

Structurally this is a grassland, but a woody layer - with an average height of 3 to 5 m - may form dense thickets in places. Oldwood Leucosidea sericea - the principal element in the woody layer, is the most conspicuous diagnostic species, while Small-leaf Guarri Euclea undulata, Bladdernut Diospyros whyteana, Cape Myrtle Myrsine africana and Rhus dentata are often present. The hot north-facing slopes are dry, poor in species, and dominated by the grasses Common Thatchgrass Hyparrhenia hirta and Copperwire Grass Aristida diffusa with Tassel Bristlegrass A. congesta dominating overgrazed sites. Other grasses include Ngongoni Bristlegrass Aristida junciformis, Redgrass Themeda triandra, Weeping Lovegrass Eragrostis curvula, Cymbopogon plurinodis, Tristachya leucothrix and Harpochloa falx. On relatively moist, steep, cooler, south-facing slopes, species-rich, dense thickets with a sparse undergrowth are dominated by a non-grassy herbaceous layer. Here the annual grass Annual Bluegrass Poa annua, the forbs Wild Phlox Sutera polelensis, Woundwort Stachys kuntzei and Small Arum Lily Zantedeschia albomaculata, and the lianas Sticky Madder Rubia horrida and Traveller's Joy Clematis oweniae, are characteristic components. Cape Waitabit Myrsiphyllum asparagoides, Wild Dagga Leonotis dysophylla, Lightningbush Clutia pulchella and the Parsley Fern Cheilanthes quadripinnata are often present.

Key Environmental Parameters:

This is mountain grassland, with the typical cool, wet Drakensberg montane climate and severe frost. Occasional snow and frequent burning have a major influence on the vegetation. The soils of the slopes are highly erodible.

Economic Uses:

The vegetation is utilised for grazing, but due to its scenic beauty the major economic use of the vegetation type is ecotourism.

Conservation Status:

This vegetation type is well conserved in the important Golden Gate National Park and Qwa-Qwa Conservation Area. Due to the inaccessibility of many parts of this vegetation, it is fairly well conserved, though overgrazing and severe erosion can be observed locally.

Key References:

Smit (1992), Eckhardt (1993), Eckhardt et al. (1993a, c), Smit et al. (1993).

Authors:

George Bredenkamp, Noel van Rooyen & Ed Granger.