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the south-eastern and eastern parts of the country (to the east of the eastern edge of the Kalahari sands) where they occur on suitable rocky outcrops, a number of species, particularly members of the Asclepiadaceae, are able to survive in the Kalahari sands area under semi-desert conditions (see Hargreaves 1990 and Plowes 1989). Succulents occur all over Zimbabwe, but the greatest numbers are in the eastern highlands area (see Percy-Lancaster and Richards 1991).

Conservation status

Data on the conservation status of southern African succulent species were obtained from a variety of sources. The primary sources were the Southern African Red Data Book: Plants — Succulent and Nama-Karoo Biomes (Hilton-Taylor, in prep.) and the Red Data List of southern African plants (Hilton-Taylor 1996b) and the subsequent update (Hilton-Taylor 1996c). The latter is a collaborative project with information obtained from the threatened plants databases maintained by the various conservation agencies in southern Africa (Cape Nature Conservation: R. Stanvliet and T. Anderson; Natal Parks Board: R. Scott-Shaw; Orange Free State Directorate of Nature and Environmental Conservation: J. du Preez; Transvaal Directorate of Nature and Environmental Conservation: W. Boyd; Namibian Ministry of Tourism and Environment: M. Strohbach; National Herbarium of Namibia: G. Maggs; and the Swaziland National Trust Commission: K. Braun). A number of publications on the threatened plants of specific geographical or political regions also provided valuable baseline data, particularly on the past conservation status of certain taxa. These included Everard (1988); Fourie (1984, 1986); Hall et al. (1980); Hall and Veldhuis (1985); Hilton-Taylor and Smith (1994); Jankowitz (1975, 1977); Kimberley (1971, 1975, 1980, 1991) and Müller (1985). Information was also obtained from the Plants Database maintained by WCMC, particularly for Zimbabwe. In addition, a number of amateur and professional botanists were consulted and are listed in the acknowledgements.

All the data obtained is stored in a database (known as 'SARARES') developed at the Ecology and Conservation Research division of the National Botanical Institute in Kirstenbosch, Cape Town. This database is updated regularly, and it is hoped that it will provide the basis for the future development of a southern African threatened plants working group, which will enable better coordination of research and conservation activities concerning threatened plants across the subcontinent. Having all the data in one centralised database, also enables one to look at the conservation status of each species across its entire distribution range rather than in just certain political or geographical areas. This will help to prevent limited conservation resources being spent unnecessarily on species which are only locally threatened. The conservation status as listed in Annex 8, is therefore the global status for each taxon. Only seven of the 576 taxa listed are not endemic to the FSA region, and all of these are in effect endemic to the greater southern African region in that they occur in the adjoining countries of Angola, Mozambique, and/or Zimbabwe, where they are also under threat.

The IUCN Red List Categories (see Annex 16) were used in describing the conservation status of each taxon considered to be rare or threatened. In some cases where there was uncertainty as to which category was most appropriate hybrid categories as used by the WCMC were given. A new set of categories with rigorous quantifiable criteria has been developed (see Mace et al. 1993; Mace and Stuart 1994; IUCN 1994b) but have not been used here as much of the southern African data is too sparse to apply the new criteria at this stage. Once consensus has been reached on which taxa should be on the southern

Table 3.6 Numbers of globally threatened succulent taxa in the Flora of southern Africa region based on information in Annex 8

EX = Extinct in the Wild, E = Endangered, V = Vulnerable, R = Rare, 1= Indeterminate, K = Insufficiently known, Percent = percentof total number of succulent species in that family in FSA region which are threatened.

Family EX E V R 1 K Total Percent

Aizoaceae

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