Distribution in southern Africa

Although succulents are found in practically all parts of southern Africa, by far the greatest numbers of species, genera, and families are found in the western arid parts of the region (Hilton-Taylor 1994, 1996a; Van Jaarsveld 1978) (see also Chapter 1 for details on their distributions). In terms of phytochoria, biomes, and vegetation types, succulents within South Africa tend to predominate in the Karoo-Namib Region (see White 1983), the Desert, Succulent Karoo, and Nama-Karoo Biomes (sensu Rutherford and Westfall 1986), and in the various karroid and false-karroid Veld Types (vegetation types) described by Acocks (1953). J├╝rgens (1990) coined the term "leaf succulent zone" to describe part of this area which is extremely rich in leaf succulent species. High numbers of succulent species are also found in dry habitats along the east coast of South Africa, extending from the Eastern Cape along the coast of KwaZulu-Natal, through Swaziland into the Eastern and Northern Transvaal (see Figure 3.1). Succulents generally avoid the interior plateau above the Great Escarpment because of the occurrence of frost (Figure 3.1). Some species, however, are able to survive the harsh highveld winters by establishing themselves in relatively frost-free niches or by developing a degree of tolerance to frost as for example, in some of the Aloe species (see Hilton-Taylor and Smith 1994).

Succulent taxa occur in nearly all parts of Namibia except for the central dune field of the Namib Desert and the sandy and semi-humid eastern and north-eastern parts. Major centres of endemism with concentrations of succulent species in Namibia include the Southern Namib Desert (Sperrgebiet or Diamond Area No. 1), the Hunsberge, the Warmbad-Pofadder region, the Karasberge, Damaraland, and the Kaokoveld.

In Botswana, although succulents are mostly found in

Table 3.5 Numbers of succulent, pachycaul and caudiciform taxa found in Zimbabwe

(Source: Totals modified from Percy-Lancaster and Richards, 1991.)

Table 3.5 Numbers of succulent, pachycaul and caudiciform taxa found in Zimbabwe

(Source: Totals modified from Percy-Lancaster and Richards, 1991.)

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