The Desert Biome of South Africa

The Desert Biome is essentially the Namib Desert. It is a coastal plain, 100-150 km wide, stretching from southern Namibia to southern Angola. The southern part of the desert is characterised by a spectacular sea of linear and crescent-shaped sand dunes (some reach 300 m in height above the desert floor). The northward march of the dunes is blocked by the occasional flooding of the Kuiseb River. North of the Kuiseb, the dunes give way to gravel plains that are dotted with inselbergs of granite, schist and limestone.

The Namib Desert is an extreme desert, with a mean annual rainfall ranging between 5 mm in the west and 85 m in the east. Coastal fog, a characteristic feature of the Namib, is the desert’s crucial life-support system. It is this fog that contributes to the remarkably high diversity of animal life in this extremely arid environment.

The vegetation of the Desert Biome is characterised by theriophytes that persist as seeds through extended periods of drought. After good rainfall (at least 20 mm), the desert undergoes an incredible transformation, with an explosion of mainly Stipagrostis grasses. Other interesting plants of this desert include the well-known Welwitschia mirabilis, the camelthorn tree Acacia erioloba, various succulent plants, and a magnificent diversity of lichens.

Of the 89 desert vertebrates that occur in the Desert Biome, 29 are endemic. These include many reptiles (23 of 42 are endemic), three endemic mammals (a bat and two gerbils) and three endemic birds. The Namib Desert is probably best known for its very high species richness of beetles, particularly those belonging to the family Tenebrionidae.