Cape Floristic Region

The Cape Floristic Region is located at the southwestern tip of the African Continent and lies entirely within the borders of South Africa. It is one of the five Mediterranean-type systems on the hotspots list, and is one of only two hotspots that encompass an entire floral kingdom (the other being New Caledonia). Indeed, despite having extremely infertile soils, this region has the greatest extratropical concentration of plant species in the world, with 9 000 plant species, 6 210 of them endemics, crammed into just 78 555 km². Furthermore, diversity and endemism are impressive not just at the species level, but at the generic and familial levels as well, with this region accounting for five of South Africa's 12 endemic plant families. Among the hotspots, only Madagascar and the Indian Ocean Islands (8) and New Caledonia (5) have comparable family-level endemism.

The characteristic and most widespread vegetation of the Cape, covering some 46 000 km², is fynbos, an Afrikaans word that translates as “fine bush” (Kruger 1979). Fynbos is a shrubland comprising hard-leafed, evergreen, fire-prone shrubs, which are, in geological terms, a relatively recent feature (Cowling and Richardson 1995). Before the predominance of these shrublands, the region was covered with a lush rainforest of mixed Gondwanan-Paleotropical affinities (Linder et al. 1992). With the development of the cold Benguela Current along the Cape west coast about 15 million years ago, there was a subsequent deterioration in climate, resulting in a retreat of the forests. They were replaced by flammable sclerophyllous plants, relatives of the ancient lineages that had persisted on locally dry sites since the birth of flowering plants.

Many different fynbos vegetation types have been described by plant ecologists (Cowling et al. 1997), and fynbos is characterized by four major plant types: restioids, ericoids, proteoids, and bulbs. Restioids, mainly members of the Gondwanan family Restionaceae, are evergreen rush or reed-like plants that are the uniquely diagnostic plant type of fynbos. The ericoids include more than 3 000 species of small-leafed shrubs (0.5–2 m tall), which give fynbos a heath-like appearance. The proteoids are the tallest fynbos shrubs (2–4 m), and comprise showy members of the Proteaceae, another Gondwanan family, among them the king protea (Protea cynaroides), South Africa's national flower. Finally, fynbos includes more than 1 500 species of bulbs or geophytes, many of which have been developed worldwide as valuable horticultural plants, e.g., freesias, agapanthus, gladioli, and ixias.

The Cape also includes several non-fynbos vegetation types. Of these, Renosterveld (Afrikaans for “rhinoceros veld,” referring to the presence of the black rhinoceros [Diceros bicornis], that used to browse there but is now extinct in this region) is the most extensive, covering some 20 000 km². This community comprises a low shrub layer (1–2 m tall) of mainly ericoids, usually dominated by the renosterbos (Elytropappus rhinocerotis, Asteraceae), with a ground layer of grasses and seasonally active bulbs.

Trees are very rare in pristine Cape landscapes and true forests occupy a mere 3 850 km², mostly in moist, fire-protected sites on the southern coastal forelands and lower mountain slopes. The Cape forests, 10–30 m tall, are essentially outliers of the Afromontane forests of the high mountains of tropical Africa, but also include relics from the mesic Tertiary times. A form of dwarf forest, 3–5 m tall and locally known as thicket, occupies about 4 500 km² of fire-protected habitat (mainly coastal dunes and river valleys) in drier areas; thicket is compositionally related to the subtropical forests of the Indian Ocean coastline (Vlok et al. 2003). In contrast to the plants of the fynbos and renosterveld, forest and thicket plants are not chemically and structurally adapted to burn, and new individuals that germinate from bird-dispersed fruits establish only over extended, fire-free periods.

The Cape owes its status as a distinct floral kingdom to the presence of five endemic plant families (of a total of 164), and 160 endemic genera (17% of 942 genera). Certain genera have undergone massive diversification —the 10 largest genera account for 21.5% of the flora—, with the two most speciose being Erica (Ericaceae: 658 species) and Aspalathus (Fabaceae: 257 species). Species richness and local endemism is greatest in the southwest; the Cape Peninsula (471 km²) alone supports 2 256 species (including 90 endemics).

Diversity and endemism among the fauna of the Cape Floristic Region appears to be much lower than in plants, although very little is known about some invertebrate groups (Johnson 1992). There are 90 mammal species recorded from the Cape Floristic Region, of which four are endemic. The list of endemic species includes two species of golden moles: the Fynbos golden mole (Amblysomus corriae) and Van Zyl's golden mole (Cryptochloris zyli, CR). The best mammal flagship in the region is the bontebok (Damaliscus pygargus pygargus, VU), a beautiful animal whose name in Afrikaans means “brightly colored antelope” and which was saved from extinction only by the foresight of conservationists.

Bird diversity, too, is not particularly high, owing to the structural uniformity of the vegetation and the shortage of food (McMahon and Fraser 1988). Only 324 regularly occurring species have been recorded from the region, and just six of these are endemics. Nonetheless, the area is considered an Endemic Bird Area by BirdLife International (Stattersfield et al. 1998), and is home to a number of true fynbos species such as the Cape sugarbird (Promerops cafer), one of only two species in the family Promeropidae; the orange-breasted sunbird (Nectarinia violacea); and the Protea canary (Serinus leucopterus).

Reptile diversity, on the other hand, is moderately high at 100 species, of which 22 are endemic. Among reptiles, the tortoises are the best flagship species, with five species occurring almost entirely within the Cape Floristic Region, including the South African bowsprit or angulate tortoise (Chersina angulata), the leopard tortoise (Geochelone pardalis), and the geometric tortoise (Psammobates geometricus, EN). The latter is among the most threatened tortoises in the world, having already lost some 97% of its original habitat to extensive agricultural development; its remaining habitat amounts to no more than 5 000 ha, and its population is estimated at only 2 000–3 000 individuals in 31 different localities (Baard 1997).

Amphibians and freshwater fish, though low in overall diversity, exhibit high endemism. In all, there are 51 species of amphibians (in 16 genera), 16 of them endemic (although no genera or families are endemic), and they include species like the enchanting arum lily frog (Hyperolius horstocki, VU) which, as its name suggests, lives within the flower of the arum lily (Zantedeschia aethiopica). In addition, two amphibian genera are endemic, both represented by single species: the micro frog (Microbatrachella capensis, CR), which is found in sandy, coastal fynbos heathland, and the montane marsh frog (Poyntonia paludicola), a species of mountain fynbos heathland. Of the 34 native fish species, 14 are endemic. Some distinctive fishes in the clear mountain streams characteristic of this region are the Cape galaxias (Galaxias zebratus), a peculiar, elongated and scaleless fish, as well as several endemic species of redfin minnows (Pseudobarbus spp.) (Skelton 1993).

Much less is known about the invertebrate fauna of the Cape. However, the few groups that have been studied suggest very high levels of endemism. For example, of the 234 species of butterflies in the region, 72 are endemic (Rebelo 1992). One regional study, carried out on the Cape Peninsula, recorded 111 invertebrate endemics in 471 km2, a higher number than for plant endemics (Picker and Samways 1996).

The Cape Floristic Region is seriously threatened by a battery of human activities that have seen the Coast Renosterveld and Sandplain Fynbos, both lowland habitats, reduced by 48% and 83% of their original extent, respectively; much of what remains exists in small and isolated fragments in a matrix of chemically treated agriculture (Rouget et al. 2003a). Even in the mountains, where impoverished soils previously limited agriculture, farming based on indigenous crops such as rooibos tea (Aspalathus linearis), honeybush tea (Cyclopia spp.), and cut flowers (mainly Proteaceae) is rapidly encroaching on natural habitat. Nonetheless, the greatest threat to the Cape Flora overall is undoubtedly the invasion of alien plants (Richardson et al. 1992), mainly originating from other Mediterranean-type climate regions such as southern Australia (wattles [Acacia spp.], myrtle [Leptospermum laevigatum]), the Mediterranean Basin (Pinus halepensis, P. pinaster), and California (P. radiata). Originally introduced to supplement the meager Cape tree flora, these fire-adapted species have invaded about 70% of both mountain and lowland fynbos. Overall, some 33% or 23 600 km² of the Cape Floristic Region has been transformed by agriculture, urbanization, and dense stands of alien plants (Rouget et al. 2003a). However, of the remaining area, only about 20% can be regarded as pristine in the sense that it is entirely free of alien plants and subjected to appropriate fire and grazing regimes.

An analysis of the World Database on Protected Areas reveals that approximately 14% of the hotspot has some level of protection, of which at least 13% of the hotspot area is classified in IUCN categories I to IV. However, according to Rouget et al. (2003b), approximately 25%, or 19 350 km2, of the Cape Floristic Region (including the Little Karoo enclave) is conserved in 189 protected areas. Statutory conservation areas (protected areas with secure organizational and institutional support) comprise 49% of this area, whereas non-statutory reserves (mainly private conservation initiatives) comprise the remainder. Despite a relatively healthy proportion under some form of conservation management, these reserves were established in an ad hoc manner and are not entirely representative of the Cape's biota. Thus, some 50% of mountain landscapes are conserved, exceeding targets for many individual habitat types, whereas only 9% of the lowlands are conserved. Furthermore, the conservation area does a relatively poor job in protecting the ecological and evolutionary processes that maintain the Cape's unique biodiversity. Obvious priorities include remnant habitat in the highly vulnerable and poorly conserved lowlands, as well as the expansion of upland reserves to accommodate the full spectrum of species and processes.

However, there have been some positive developments on the conservation front, including: the successful initiation of the “Working for Water Programme,” which aims to deliver a major fynbos ecosystem service—clean and plentiful supplies of water— cost-effectively by removing all alien plants from mountain catchments; the expansion of protected areas through proclamation of the Cape Peninsula National Park and the Cape Agulhas National Park; and investment by the Critical Ecosystem Partnership Fund (CEPF) and the Global Environmental Facility (GEF) to develop and implement a strategic plan for the sustainable conservation of the Cape Flora and associated biota (Cowling and Pressey 2003). Of particular interest within CEPF's $6-million investment portfolio is support for the region's three mega-reserves: Baviaanskloof, Cederberg, and Gouritz, where funds have been used to prepare strategic management and business plans to ensure that these areas will be able to meet future conservation challenges. Emphasis has also been placed on building the capacity of previously disadvantaged local conservationists through a $1-million CEPF small-grants fund administered by the Table Mountain Fund. If the programs mentioned above continue to be successful, then there is every hope that future generations will be able to benefit from and marvel at this most extraordinary biological phenomenon.

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