Biomes can be defined as the major communities of the world, classified according to their predominant vegetation and characterized by adaptations of organisms to that particular environment.
Ecosystems are communities of organisms that inhabit specific physical environments. Biomes are composed of several ecosystems and represent a regional community of organisms named after the dominant vegetation.
The Succulent Karoo Savannas Fynbos Grasslands Forests Nama-Karoo Marine and Coastal Ecosystems Wetlands |
The succulent Karoo is restricted to the year-round and winter rainfall areas and has the greatest summer aridity. This biome occurs mostly west of the western escarpment through the western belt of the Western Cape and inland towards the Little Karoo. This is the land of many spring flowers, which for a few weeks each year, draw large numbers of tourists from all over the world.
Succulent plant species with thick, fleshy leaves are plentiful here, the diversity of which is unparalleled anywhere else in the world. This, together with many geophytes (plants that survive by means of bulbs, tubers, etc. in times of unfavourable climatic conditions) and annual plants, makes the succulent Karoo unique and of international importance in terms of conservation. Examples of animals that occur here are the bat-eared fox (Otocyon Megalotis), suricate (Suricata suricatta) and the common barking gecko (Ptenopus garrulus).
Savannas are the wooded grasslands of the tropics and subtropics that account for 46% of the South African landscape. They are second only to tropical forests in terms of their contribution to terrestrial primary production. They are the basis of the livestock industry and the wildlife in these areas is a key tourist drawcard.
The fact that the public is well aware of African savannas may be explained by the variety of large mammals found here. Large game species such as lion (Panthera leo), buffalo (Syncerus Caffer) and elephant (Loxodonta africana) occur here. The large diversity of animals is associated with the rich plant diversity. A well-known tree species found in the Northern Province is the baobab (Adansonia digitata). Other species found here include the mopane (Colophospermum mopane), monkey-thorn (Acacia Galpini) and knob-thorn (Acacia Nigrescens). Savannas also include valley bushveld, the veld type containing the greatest range of rainfall seasonality in South Africa. Fire is a crucial factor in the ecology of all savannas and is, therefore, a regular natural feature of this environment.
South Africa is characterised by a wide diversity of plant life and is ranked as the third most biologically diverse country in the world (mainly due to the richness of plant life). Over 18 000 species of vascular plants occur in South Africa, of which over 80% occur nowhere else. This diversity is caused by variations in climate, geology, soils and landscape forms. However, South Africa also has the highest concentration of threatened plant groups in the world. Approximately 3 435 South African plant groups are considered to be globally threatened by extinction. A further 204 groups are estimated to be threatened at a local level.
Fynbos occupies 5,3 % of South Africa, occurring almost exclusively in the south-western and southern parts of the Western Cape Province. Fynbos comprises evergreen heathlands and shrublands in which fine-leafed low shrubs and leafless tufted grass-like plants are typical. Trees are rare, and grasses comprise a relatively small part of the biomass.
Fire is a very important component in fynbos. Most fynbos is highly flammable due to the common presence of flammable oils. Finely wooded fynbos plants are obligate seeders, which means that the whole plant dies after the fire and can only reproduce through seed. This distinguishes fynbos from the other ecosystems where the fire is common. Many plant species are dependent for pollination on small mammals or birds such as the Cape sugarbird (Promerops Cafer).
Fynbos, with its complement of at least 8 578 species of flowering plants, is now recognised as supporting one of the most diverse and distinctive floras in the world. All in all, 5 832 or 68 % of the plant species are endemic. Many of the fynbos plant species are restricted to extremely small distribution ranges, a fact which has rendered them dangerously susceptible to extinction.
Economic utilisation of fynbos vegetation is limited to selective grazing by small stock on newly burned lowland areas and to wild-flower production. Most commonly utilised are the protea species, which are exported fresh or dried.
The floristic diversity of the fynbos is not paralleled by an equally rich fauna due to the absence of grass and berry-producing plants. Fauna includes species such as the leopard (Panthera pardus) and the geometric tortoise (Psammobates Geometricus).
Fynbos products such as rooibos tea, buchu, veld flowers and thatching-reed are also harvested while table and wine grapes, wheat, fruit and olives are important agricultural products. South Africa’s oldest city, Cape Town, at the foot of Table Mountain, is located in the fynbos biome.
In South Africa, invasive plants cause billions of rands of damage each year. Over 160 plant species introduced into South Africa have become invasive. If left unchecked, these species will spread at an alarming rate, doubling within 15 years. Invasive alien plants have the following impacts:
For more information:http://www-dwaf.pwv.gov.za/wfw/
The grasslands cover the high central plateau of South Africa, inland areas of Kwazulu-Natal and the mountain areas of the Eastern Cape Province. Grasslands are defined as those areas where grasses dominate the vegetation and where woody plants are absent or rare. They occupy 24,1% of the country’s surface area. Most grassland occurs in high-rainfall areas, where thunderstorms and hail are common in summer and frost is common in winter.
The grassland biome is regarded as the third-richest area in terms of plant species diversity, with a total number of 3 788 species. The most noteworthy species with a wide distribution is, Themeda Triandra, more commonly referred to as 'rooigras'. In the past, the ungulate fauna (hoofed animals) of the Highveld grasslands included vast herds of blesbok (Damaliscus Dorcas Phillipsi), black wildebeest (Connochaetes Gnou) and the springbok (Antidorcas marsupialis). A surprisingly rich variety of birds are found in the grasslands, including the blue crane (Anthropoides Paradiseus), black korhaan (Eupodotis Afra) and helmeted guineafowl (Numida meleagris).
The forests of South Africa include the indigenous evergreen and semi-deciduous closed forests of the coastal lowlands and escarpment slopes and cover only about 0.25% of the land area.
With a few exceptions such as the forests of the Knysna area and the KwaZulu-Natal coastal dune systems, forests are small, usually occupying less than 1 000 ha. These forests amount to little more than patches scattered through the higher rainfall areas. The total area of forests in South Africa is probably less than 2 000 km². The forest structure results in reduced light levels in the area beneath the canopy where species such as tree ferns are common. Typical mammals include the bushbuck (Tragelaphus scriptus), bushpig (Potamochoerus Porcus) and blue duiker (Philantomba Monticola). Birds found in forests include the Knysna lourie (Tauraco Corythaix) and Rameron pigeon (Columba Arquatrix). Despite the small land surface area that they occupy, forests have relatively high species richness. Only fynbos exceeds the species richness found in forests.
The Nama-Karoo covers most of the vast central plateau region of the Western and Northern Cape Provinces. The area forms an ecotone or transition between the Cape flora to the south and the tropical savanna in the north. Many of the plant species of the Nama-Karoo also occur in the savanna, grassland, succulent Karoo and fynbos biomes.
Species that occur in the Nama-Karoo include the sweet-thorn (Acacia karroo), stone plant (Lithops-Ruschiorum) and blue Karoo daisy (Felicia australis). The former vast migratory herds of springbok (Antidorcas marsupialis) have been replaced by domestic stock, particularly sheep and goats. A rich variety of rodents and reptiles also occurs in the Nama-Karoo. The few, endemic or near-endemic bird species include the Sclater's lark (Spizocorys Sclateri). Sheep-farming is the main agricultural activity in this region.
The South African coastline covers a distance of over 3 000 km, more than 80% of which consists of sandy beaches and sand dunes. Other ecosystems include rocky shores, coral reefs, kelp beds and the open sea. Two hundred and seventy of the world’s 325 fish families occur in South African waters.
The east coast waters are characterised by the warm waters of the southward flowing Agulhas Current, while those of the west coast is characterised by the upwelling of cold, nutrient-rich waters of the Benguela Current. Along the southwest and south coast, there is an extensive mixing of water masses. The currents influence the composition of the animal and plant communities along this coastline.
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The term "wetlands" groups together a wide range of inland and coastal habitats – from mountain sponges and midland marshes to swamp forests and estuaries – linked by rivers and streams. These wetlands share common and important functions in river catchments by providing a regular water supply, filtering the water naturally, reducing the effects of floods and droughts, and by providing vital wildlife habitat and superb recreational areas for people.
Most wetlands are characterised by a high-water table, water-carrying soil and hydrophytes (water-loving plants), but in semi-arid Southern Africa, there are numerous pans that support few if any hydrophytes and that may contain shallow water only once in five or more years.
Wetlands play an important role in maintaining biodiversity since they support an extraordinary variety of plant and birdlife e.g. the red bishop (Euplectes Orix), the South African shelduck (Tadorna Cana), insects, mammals, reptiles, amphibians, e.g. the striped stream frog (Strongylopus Fasciatus), fish and invertebrate species.
Wetland plants such as the bulrush (Typha Capensis), play an important role in the healthy functioning of a wetland ecosystem by generating organic matter, the primary element for any foodweb. They also provide the soil and water with oxygen, prevent erosion and serve as a filter that purifies the water. These plants provide food, shelter and breeding sites for many birds and aquatic animals such as the hippopotamus. Attractive plant species such as the arum lily (Zantedeschia aethiopica) and the red-hot poker (Kniphofia Caulescens) are common to wetlands. Wetlands are likely to occur in the catchment of all river systems in South Africa, but their form and abundance vary considerably owing to regional differences in topography, climate, vegetation, soil, land use and hydrological conditions. South African wetlands, being at the southern tip of the continent, host a number of endemic and highly isolated bird species, e.g. the Cape shoveller (Anas Smithii). A number of Palearctic migrants visit Southern African wetlands during the northern hemisphere's winter, some of which come all the way from the Taimyr Peninsula in Siberia (a distance of approximately 15 000 km). South Africa extends into the tropics, providing the southern limits to a number of tropical species such as the pink-backed pelican (Pelecanus Rufescens), the Rufous-bellied heron (Butorides Rufiventris), the dwarf bittern (Ixobrychus Sturmii), the open-billed stork (Anastomus Lamelligerus) and the pygmy goose (Nettapus Auritus.