endemism the endemism of vascular plants in southern africa is exceptionally high, and more like...
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ENDEMISM
The endemism of vascular plants in southern Africa is exceptionally high, and more like what you expect on an oceanic island.
This is attributable to diverse ecological conditions that has resulted in high speciation within genera (species to genus ratio is 9.6) paralleling the product of adaptive radiation occurring on oceanic islands.
Genera with many species are mostly found in Fynbos and Succulent Karoo biomes.
Compared to the global flora the southern African flora comprises a distinct phylogenetic sequence.
The southern African flora contains most of the world's species of Mesembryanthemumaceae (now Azoaceae), Ericaceae, Amaryllidaceae, Iridaceae, and Restionaceae, as well as high proportions of Geraniaceae, Proteaceae and Rutaceae.
The southern African flora has 13 endemic or near endemic families (with the revised classification – in press – this is reduced to 6 or 7).
Most of the endemic families are/were monogeneric, and mostly all are restricted to the winter rainfall regions (the CFR).
Biodiversity is not evenly distributed e.g. CFR covering 3.5% of the region has 41% of the species.
Country Endemism %
Country Endemism %
New Zealand 82 Ecuador 21
Southern Africa 80 United Status 21
Australia 80 Costa Rica 15
New Caledonia 80 Greece 15
Madagascar 68 Mexico 14
Indonesia 67 Panama 14
China 56 Algeria 8
Papua New Guinea 55 Mozambique 4
Chile 51 Nigeria 4
Zaire 29 Zambia 4
Sri Lanka 28 Zimbabwe 2
Argentina 25 Germany less than 1
Angola 24 Sweden less than 1
CENTRES Area km2
# of spp.
End. (%)
Rainmm yr-1
Rainfall Season
Vegetation
Wolkberg 5 980 2 700 4 500-2000 Summer Temp. & Subtropical Grassland
Maputaland 26 734 1 100 15 600-1200 Summer Savanna
Eastern Mountain
40 000 1 750 30 1500-2000 Summer Temperate Grassland
Pondoland 1 880 1 500 8 1000-2000 Summer Subtropical Grassland
Albany 22 500 2 000 10 350-750 All year Subtropical Thicket
Succulent Karoo
111212 4 750 35 20-300 Winter- all year
Succulent Shrubland
Cape 90 000 8 600 68 250-3000 Winter- all year
Sclerophyll Shrubland
Kaokoveld 70 000 952 12 10-300 Summer Deciduous Shrubland
Endemism, based on the IUCN centre of plant diversity project, ranges from 4% to 68% - which compares with tropical rainforest of 44%.
The Cape with 6 000 endemic spp. is the hottest hotspot, and the Succulent Karoo with 1 600 endemic spp. is the only semi-arid area that is a global hot spot.
8830 endemic spp. and exceptionally high spp. to genus ratios of southern Africa is one of the most important areas for biodiversity conservation action.
CONSERVATION STATUS
The protected area network in South Africa is not optimally located with respect to hotspots, plant diversity and endemism. Reasonably large conservation areas exist for Wolkberg and Maputaland.
Mountain areas of the Cape are well conserved. The succulent Karoo is desperately poor as are the lowlands of the Cape Floristic region. Conserved areas and number of Red Data Book (RDB) taxa in southern African centres follow …
CENTRE Area conserved %
RDB extinct RDB other
Wolkberg 13.3 0 32
Maputaland 10.0 ? ?
Eastern Mtns.
5.5 0 27
Pondoland 7.0 0 33
Albany 6.5 1 51
Succulent Kar.
2.0 18 978
Cape Lowlands
3.0 29 1406
Cape Mtns. 50.0 ? ?
Kaokoveld 7.0 ? ?
Major threats to southern African hot-spots
CENTRE Threats
Wolkberg Afforestation, invasive plants, overgrazing
Maputaland Afforestation, agric., invasives, mining, overgrazing, harvesting, tourism, urbanization
Eastern Mountain Afforestation, agric., invasives, overgrazing, plant harvesting
Pondoland Agric., invasives, harvesting, population growth, overgrazing, burning
Albany Agric., invasives, overgrazing, urbanization
Succulent Karoo Agric., mining, plant harvesting, overgrazing
Cape Agric. (lowlands), mining, harvesting, overgrazing, urbanization
Kaokoveld Overgrazing, harvesting, tourism
MEASUREMENTS OF PLANT BIODIVERSITY
α = within plot/site/stand biodiversity. E.g. CFNR plots for species area, i.e. the number of spp. in one sample of a community.
β = within community biodiversity. E.g. Between several plots in the same community/stand, i.e. the number of spp. in the whole community, or the rate of change as one moves through the community (within community change-over).
γ = within landscape biodiversity. E.g. Taking plots from the whole of the CFNR, or along an altitudinal gradient, i.e. the rates of spp. change over from one community to another in the same landscape.
δ = between landscapes e.g. Comparing the Cape Peninsula and Kogleberg, i.e. beween geographic regions.
http://www.calflora.net/southafrica/floralkingdoms.html
http://www.calflora.net/southafrica/map.html
http://www.calflora.net/southafrica/temperature.html
http://www.calflora.net/southafrica/rainfall.html
http://www.calflora.net/southafrica/temperature.html
http://www.calflora.net/southafrica/biomes1.html
http://www.plantzafrica.com/vegetation/vegimages/biomes800.jpg
http://www.calflora.net/southafrica/conservationareas.html
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