Mountain Zebra National Park has three vegetation types (Mucina et al. 2005): the Eastern Upper Karoo, Karoo Escarpment Grassland and Eastern Cape Escarpment Thicket making up 37%, 53% and 10%, respectively of the park. The park thus incorporates elements of three biomes: the Nama-Karoo, Grassland and Thicket.
The Karoo Escarpment Grassland is dominated by the grass species Merxmuellera disticha, with shrubs such as Euryops annuus, and Elytropappus rhinocerotis. The Eastern Upper Karoo is a mix of grass and shrub dominated vegetation types that are subject to dynamic changes in species composition depending upon rainfall. Shrubs such as Pentzia incana, Eriocephalus ericoides dominate, while grasses such as Aristida spp. Eragrostis spp. and Themeda triandra are common. Fires are fairly common in the Karoo Escarpment Grassland and may also occur occasionally in the Eastern Upper Karoo. The vegetation types in the Mountain Zebra National Park are poorly or hardly protected elsewhere in South Africa (Driver et al. 2005).
The combination of different vegetation types is important from the point of view of preserving biodiversity, as well as from an aesthetic viewpoint. The area is one of transition between biomes allowing for an interesting mix of flora and fauna, as well as preserving important ecological and landscape processes. The warm north-facing slopes (which characterise the park) with a wide diversity of habitats ranging from mountaintops to valley bottoms provide suitable habitat ideal to cater for the seasonal requirements of the large herbivores (Novellie et al. 1988). In addition the north aspect provides for productive land capable of supporting relatively high densities of game, with greater proportions of the more productive Karoo veld types allowing the carrying of large herbivores.
Herbivore densities within the rocky grassland areas are likely to be low. Importantly, all of the major vegetation types in the park are currently very poorly conserved elsewhere in South Africa: South Eastern Mountain Grassland (0.3% conserved), Eastern Mixed Nama Karoo (1.08%), Valley Thicket (2.2%) and Central Lower Karoo (0.05%). Hence, the park will play a critical role in the long-term preservation of biodiversity.
The interface between biomes promotes a rich flora, as well as preserving important ecological and landscape processes. An analysis of the flora (Pond et al. 2002) revealed 680 plant species in the park, thirteen of which are Red Data species. At 5.05 plant species per 100 ha, the density of plant species in the Mountain Zebra National Park is very high compared to other protected areas in the arid and semi-arid areas of South Africa, a feature which can be ascribed to the wide habitat and substrate diversity of the park (Pond et al. 2002).
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