vrijdag 24 mei 2013

South Africa, Cape Floral Region Protected Areas

A serial site – in Cape Province, South Africa – made up of eight protected areas, covering 553,000 ha, the Cape Floral Region is one of the richest areas for plants in the world. It represents less than 0.5% of the area of Africa but is home to nearly 20% of the continent’s flora. The site displays outstanding ecological and biological processes associated with the Fynbos vegetation, which is unique to the Cape Floral Region. The outstanding diversity, density and endemism of the flora are among the highest worldwide. Unique plant reproductive strategies, adaptive to fire, patterns of seed dispersal by insects, as well as patterns of endemism and adaptive radiation found in the flora, are of outstanding value to science.




The Cape Floral Region is located in the south-west corner of South Africa in the Cape Province. The site's eight clusters form a representative sample of the eight phytogeographical centres of the region. Elevations range from 2,077 m in the Groot Winterhoek to sea level in the De Hoop Nature Reserve. A great part of the area is characterized by rugged mountain passes, rivers, rapids, cascades and pools.
The area has been called the world's 'hottest hot-spot' for plant diversity and endemism and has been designated as one of the World Centres of Plant Diversity. It has some 44% of the subcontinental flora of 20,367 species (vascular plant species), including endemic and subendemic families and threatened species. The Cape Peninsula contains almost half of these species, with 25% of the flora of the whole region. The richness is due to the wide variety of macrohabitats and microhabitat mosaics resulting from the range of elevations, soils and climatic conditions, including the co-existence of winter-rainfall species with summer-rainfall species from further east. The flora is also characterized by concentrations of relict endemics and massive ongoing speciation due to its isolation in an area of very long established climatic stability. The flora of each area is sufficiently distinct to justify representation of the region by several sites, each of which is large enough to preserve the genetic viability of its types of diversity and to accommodate large-scale natural processes such as fire and drought. Eight phytogeographical centres of endemism have been distinguished in the Cape Floral Region.
The distinctive flora of the region, comprising 80% of its richness, is the fynbos (fine bush), fine-leaved vegetation adapted to both the Mediterranean type of climate and to periodic fires, and defined by the location or dominant species. Plant variety is based on soil types which vary from predominantly coarse, sandy, acidic nutrient-poor soils, to alkaline marine sands and slightly richer alluvials. There are pockets of evergreen forest in fire-protected gorges and on deeper soils; in the east are valley thickets and succulent thickets, which are less fire-dependent, and in the drier north, low succulent Karoo shrubland.
Four other characteristics of the Cape Floral Region of global scientific interest are:
  • the responses of the plants to fire;
  • seed dispersal by ants and termites;
  • the high level (83%) of plant pollination by insects, mainly beetles and flies;
  • its linkages to Gondwanaland allowing reconstruction of the flora's ancient connections.
Adaptation to fire include geophytes that sprout from underground and seed storage both underground and in the canopy, some species requiring fire for germination. Ants take the seeds to eat the lipid deposits; about 28% of the region's flora, including over half of the Proteaceae, is dispersed by them. Most of the shrubs so dispersed are both endemic and threatened species but the latter lack a way of regenerating after fire. Pollination and nutrient-cycling by termites, and termite-mound communities are notable and the region has very high levels of bird- and mammal-pollinated plants.

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