GC7K7J3 HP6 Biomes (Traditional Cache) in Gauteng, South Africa created by WorsEd

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The Biomes and vegetation of South Africa

At is simplest, vegetation can be described as the group of plants forming the plant cover of a geographical area. As humans, we tend to classify things, and so vegetation has been classified too. Vegetation types are typically used in classifying biomes.

Biomes (large-scale biotic communities) have been described for plants and/or animals living together with some degree of permanence, so that large-sized patterns in global plant cover can be observed. Biomes broadly correspond with climatic regions, although other environmental controls are sometimes important. Each biome has a characteristic set of plant and animal species as well as a characteristic overall physiognomy ( for example a general appearance given by the plant shapes.

Biomes are also referred to as habitats, but the term can also refer to a set of conditions/ factors within which a specific organism lives for example a vlei, an anthill or a koppie.

In South Africa there are eight distinctive plant growth zones or biomes:

Savanna Biome

This is the largest of all of the biomes in southern Africa, covering 46% of its area and over one third the area of South Africa. It is well developed over the lowveld and Kalahari region of South Africa and is the dominant vegetation in neighbouring Botswana, Namibia and Zimbabwe.
It is characterized by a grassy ground layer and a distinct upper layer of woody plants. Where this upper layer is near the ground the vegetation may be referred to as shrubveld.
Rainfall in these areas varies from 235 to 1000mm per year, frost may occur 0 to 120 days per year, and almost every major geological and soil type occurs within the biome. A major factor delimiting the biome is the lack of sufficient rainfall which prevents the upper tree layer from dominating, coupled with fires and grazing, which keep the grass layer dominant. Summer rainfall is essential for grass dominance.
Most of the Savanna vegetation types are used for grazing, mainly by cattle or game.

Grassland Biome

This biome is found chiefly on the high central plateau of South Africa, and the inland areas of Kwazulu-Natal and the Eastern Cape. The topography is mainly flat and rolling, but includes the escarpment itself. Altitudes varies from near sea level to 2850m above sea level.
Grasslands are dominated by a single layer of grasses. The amount of cover depends on rainfall and the degree of grazing. Trees are absent, except in a few localised habitats. Frost, fires and grazing maintain the grass dominance and prevents the establishment of trees.
There are two categories of grass plants: sweet grasses have a lower fibre content, maintain their nutrients in the leaves in winter and are therefor palatable to stock. Sour grasses have higher fibre content and tend to withdraw their nutrients from the leaves duringwinter so that they are unpallatable to stock and have low nutitional value
Much of the Grassland Biome has been converted to corn production.
The Grassland Biome is considered to have an extremely high biodiversity, second only to the Fynbos Biome. Rare plants are often found in the grasslands, especially the escarpment area. Very few grasses are rare or endangered.

Forest Biome

Forests are restricted to areas with mean annual rainfall of more than 525mm in the winter rainfall region and 725mm in the summer rainfall region. They occur from sea level to over 2100m above sea level. At higher elevations they may be limited by the extended frost season. Forests rarely burn, mainly due to the high humidity. Forests tend to occur in patches, few of which covers areas grater than a square kilometre, with areas greater than this only common along the South Coast and Lowveld Escarpment. Even added together forests cover less than 0,25% of soutern Africas surface area, making it the smallest biome of the subcontinent, and the smallest temperate forest biome in the world.
The canopy cover of forests is continuous, comprising mostly evergreen trees, and beneath the vegetation is multi-layered. The ground layer is often poor developed due to the dense shade.

Fynbos Biome

The Fynbos Biome is considered by many to be synonimous with the Cape Floristic Region. The Cape Floral Kingdom is the smallest of the six Floral Kingdoms in the world, and is the only one contained in its entirity within a single country. It is characterised by its richness in plant species (9000 species) and its high endimicity (68% of plant species are confined to the Cape Floral Kingdom).
Although this biome covers less than 6% of the area of the country, it contains over one third of all plant species in South Africa.
Distressingly, some three-quarters of all plants in the South African Red Data Book occur in the Cape Floral Kingdom: 1700 plant species are threatened to some extent with extinction. The biggest threat to this biome is urban expansion but more seriously is the threat of alien plants. Fynbos must burn, but fires in the wrong season or too frequently eliminate species.

Thicket Biome

Thicket vegetation occurs instead of forest where there is a degree of fire protection, but rainfallis too low to support forests. Thickets do not have the required height to be classified as forests, and the strata below the canopy is poorly developed. Nor are they Savanna type, in that there is no consicuous grassy ground layer.
Subtropical thicket is a closed shrubland to low 'forest' dominated by evergreen, sclerophyllous or succulant trees, shrubs and vines, many of which have stem sines. It is often almost impenetrable, is generally not devided into strata, and has little herbaceous cover. Thicket types contain few endemics, most of which are succulents of Karoo origin.
At least 5 thicket types are recognised on the basis of their distribution and the degree of succulance in the shrub and tree species: Dune Thicket, Valley Thicket, Xeric Succulent Thicket, Mesic Succulant Thicket and Spekboom Succulent Thicket.

Nama Karoo Biome

This biome occurs on the central plateau of the western half of South Africa. at altitudes between 500 and 2000m, with most of the biome falling between 1000 and 1400m. It is the second largest biome in the region.
The geology undrlying the biome is varied, as the distribution of this biome is determined primarily by rainfall. The rain falls in summer, and varies beween 100 and 520mm per year. This also determines the predominant soil type - over 80% of the area is covered by a lime-rich, weakly developed soil over rock. Although lerss than 5% of rain reaches the rivers,the high erodibility of soils poses major problems where overgrazing occurs.
The dominant vegetation is grassy, dwarf shrubland. Grasses tend to be more common in depressions and on sandy soils, and less abundant on clayey soils. Grazing rapidly increases the relative abundance of shrubs.
The amount and nature of the fuel load is insufficient to carry fires and fires are rare within the biome.
The large historical herd of Springbok and other game no longer exists. The Brown Locust and Karoo Catterpillar exhibit eruptions under favourable, local rainfall events, and attract large numbers of birds and mammal predators.Most of the land is used for grazing, by sheep and goats.

Succulent Karoo Biome

Most of the biome covers a flat to gently undulating plain, with some hilly and broken veld, mostly situated to the west and suth of the escarpment, and north of the Cape Fold Belt. The altitude is mostly below 800m, but in the east it may reach 1500m. A variety of geological units occur in the region. The soil is lime-rich, weakly developed and on rock.
The biome is primarily determined by the presence of low winter rainfall and extreme summer aridity. Rainfall varies between 20 and 290mm per year. Because the rains are cyclonic, and not due to thunderstorms, the errosive power is far less than of the summer rainfall biomes. During summer temperatures in excess of 40 degrees Celsius are common. Fog is common neare to the coast.
The vegetation is dominated by dwarf, succulent shrubs, of which Vygies and Stonecrops are particularly prominent.Mass flowering displays of annuals ( mainly Daisies and Asteraceae) occur in spring, often on degraded or fallow lands. Grasses are rare, except in some sandy areas.The number of plant species mostly succulents- is very high and unparalleled elsewhere in the world for an arid area of this size.
Ostrich farming with considerable supplementary feeding is practised in the Little Karoo in the sout of the biome.

Extreme Desert Biome

"true" desert is found under very harsh environmental conditions which are more extreme than those found in the Succulent Kasroo Biome and Nama Karoo Biomee. The climate is characterised by occasional summer rainfall, but high levels of summer aridity. Mean rainfall is from approximately 10mm in the west to 80 mm on the inland margin of the desert. In reality, the rainfall is highly variable from year to year. Most true desert in souterh Africa is found in Namibia, although an outlier does occur in a small part of Sout Africa, mainly in the Springbokvlakte area of the Richtersveld in the lower Orange River valley.
The vegetation is characterised by dominance of annual plants. This means that after a season with rarely abundant rains, the desert plains can be covered with a sea of short grasses. In normal years, the plains can appear bare with the annual plants persisting in the form of seed.
The Desert Biome includes an abundant insect fauna which includes many tenebrionid bettles, some of which can utilize fog water.

Sources

http://www.plantzafrica.com/vegetation
Cowling,RM, Richardson,DM &Pierce,SM. 1997, Vegetation of Southern Africa. Cambridge University Press, Cambridge,UK.
Wikipedia
Butchart,D. 2012,Natuurlewe van Suid-Afrika.Struik Uitgewers, Kaapstad RSA.

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