The flora of the Addo Elephant National Park, South Africa: Are threatenedspecies vulnerable to elephant damage?

The Addo Elephant National Park in the warm-temperate Eastern Cape was proc laimed in 1931 to protect one of the four elephant populations in South Afr ica which survived into the present century. However, since the late 1970s, a major objective of the Park is to protect intact a viable example of suc culent thicket - the regional ecosystem. Succulent thicket is endemic to th e Eastern Cape and forms the major component of the Albany Centre, a floris tic region of high diversity and endemism, especially among succulent shrub s and geophytes. This ecosystem is poorly represented in the reserve system and is highly threatened by overgrazing and clearing for agriculture. Unde r the present stocking rate of more than two elephants/km(2), succulent thi cket in the Park has been severely impacted: in particular, biomass, statur e and plant diversity have been reduced. We show that the flora of the Park is of great regional significance. Of a total of 581 species, 12.4% were c lassified as regional endemics and/or Red Data Book species (collectively t ermed 'species' of special concern), and 32.2% were not known to be conserv ed in any other succulent thicket protected area. Relative to the remainder of the flora, both categories of species were over-represented among succu lent shrubs (predominantly Euphorbiaceae and Mesembryanthemaceae) and geoph ytes (predominantly Asphodelaceae and Hyacinthaceae). This taxonomic and bi ological profile coincides with that of species vulnerable to local extinct ion as a result of elephant impacts. The Park authorities will need to find a solution to the conflict between maintaining a large population of megah erbivores, and maintaining the structure and diversity of succulent thicket .