43. North-eastern Mountain Grassland

Synonyms:

North-eastern Mountain Sourveld (A8), North-eastern Sandy Highveld (A57), Piet Retief Sourveld (A63); Loudetia simplex-Diheteropogon filifolius Grassland, Monocymbium ceresiiforme-Tristachya leucothrix Grassland.

Statistics:

42 458 km²; ± 45% transformed; 7.42% conserved.

Locality & Physical Geography:

This type comprises the grasslands of the northern parts of the great escarpment mountains in Mpumalanga. It stretches northwards along these mountains into Northern Province, and southwards through KwaZulu-Natal, reaching the northern parts of Eastern Cape. Altitude ranges from 1 400 to 1 900 m.

Climate:

The summer rainfall ranges from 700 to 1 100 mm per year. Temperatures vary from -8°C to 39°C, with an average of 15°C.

Geology & Soil.

Soils are mostly shallow lithosols derived from a variety of rock types.

Vegetation:

This grassland type contains many endemic plant species: 78 endemic or near-endemic species occur on the Black Reef quartzites. These are mostly representatives of the Lilies (Liliaceae - now split into several families), Irises (Iridaceae), Daisies (Asteraceae), Mints (Lamiaceae) and Orchids (Orchidaceae). A further 31 endemic species occur on the drier dolomites of the Chuniespoort Group. These are all grassland species - no forest species are endemic to the vegetation type. Typical species, always present, include the grasses Common Russetgrass Loudetia simplex, Giant Speargrass Trachypogon spicatus, Threadleaf Bluestem Diheteropogon filifolius, Aristida junciformis, Tristachya leucothrix, Alloteropsis semialata, Eragrostis racemosa, Sporobolus pectinatus and Microchloa caffra, and forbs such as Aeschynomene nodulosa, Geelkeurtjie Eriosema angustifolium, Bracken Pteridium aquilinum, Berkheya echinacea, Pearsonia sessilifolia, Crassula alba, Vernonia centaurioides, V natalensis, Clutia monticola, Stiburus alopecuroides, Helichrysum wilmsii, H. cephaloideum, H. acutatum and H. pilosellum. A number of species are, however, restricted to the mist belt zone of high mountain peaks and summits (exceeding 1 700 m). These include Tussock Fescue Festuca costata, Toothbrush Grass Rendlia altera, Everlasting Helichrysum platypterum, H. umbraculigerum, H. mariepscopicum, Selago hyssopifolia, Rabdociella calycina, Lobelia flaccida, Scilla ner vosa, Craterocapse tarsodes, Wahlenbergia squamifolia, Crassula vaginata, Hemizygia subvolutina and many more. At relatively lower altitudes, below 1 700 m, grass species such as Natal Panic Panicum natalense, Sicklegrass Ctenium concinnum, Junegrass Koeleria capensis and Eulalia villosa, forbs such as Everlasting Helichrysum oreophilum, Gifbossie Gnidea caffra, lndigofera sanguinea and Monsonia attenuata, and the woody species, Broadleaf Beechwood Faurea rochetiana, Common Sugarbush Protea caffra and African Sugarbush P. gaguedi are considered as diagnostic. Forest-related bush clumps occur on the Black Reef quartzites, situated at the edge of the escarpment in this area. Here woody species include Bastard Lemonwood Psychotria capensis, Broadleaf Waxberry Myrica pilulifera, Cape Beech Rapanea melanophloeos, Blueberry Vaccinium exul, Cliffortia serpyllifolia, Psydrax livida, Protea roupelliae, Rhus tumulicola, Aloe arborescens, Passerina montana, Ekebergia pterophylla, Erica caffrorum and Englerophytum magalismontanum.

Key Environmental Parameters:

Although it is predominantly a grassland area, Acocks classified North-eastern Mountain Sourveld as an Inland Tropical Forest type, due to the patches of forest occurring in the sheltered ravines, gorges and valleys of the escarpment. North-eastern Mountain Grassland is restricted to the high altitude escarpment areas of Mpumalanga and Swaziland. The rainfall is high, mist plays an important role, while low temperatures, frost, snow and fire are also important determinants of this vegetation type.

Economic Uses:

Forestry, grazing and ecotourism are the most important economic activities.

Conservation Status:

This is an area with many rare and endemic plant species, which are often threatened by the expanding forestry industry. Many patches of natural forest occur in the escarpment area of this grassland. The Blyde River Canyon

Nature Reserve is an important conservation area, but others include Gustaf Klingbiel, Mount Sheba and Pilgrim's Rest Nature Reserves.

Key References:

Deall et al. (1989), Matthews et al. (1992, 1993), Burgoyne (1995).

Authors:

George Bredenkamp, Ed Granger & Noel van Rooyen.