Succulent Karoo Biome has an equal status to the other biomes in
South Africa - it is not a subtype of "a 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 south
of the escarpment, and north of the Cape Fold Belt. The altitude
is mostly below 800 m, but in the east it may reach 1 500 m. A variety
of geological units occur in the region. There is little difference
between the soils of the Succulent Karoo and Nama Karoo Biomes -
both are lime-rich, weakly developed soils on rock. The Olifants
and Doring Rivers are the major drainage systems in the west, with
the Gouritz River in the south-east of the biome.
The Succulent Karoo Biome is primarily determined by the presence
of low winter rainfall and extreme summer aridity. Rainfall varies
between 20 and 290 mm per year. Because the rains are cyclonic,
and not due to thunderstorms, the erosive power is far less than
of the summer rainfall biomes. During summer, temperatures in excess
of 40°C are common. Fog is common nearer the coast. Frost is infrequent.
Desiccating, hot, Berg Winds may occur throughout the year.
The vegetation is dominated by dwarf, succulent shrubs, of which
the Vygies (Mesembryanthemaceae) and Stonecrops (Crassulaceae) are
particularly prominent. Mass flowering displays of annuals (mainly
Daisies Asteraceae) occur in spring, often on degraded or fallow
lands. Grasses are rare, except in some sandy areas, and are of
the C3 type. The number of plant species mostly succulents - is
very high and unparalleled elsewhere in the world for an arid area
of this size.
Little data are available for the fauna of the Succulent Karoo.
Of importance in the area are heuweltjies, raised mounds of calcium-rich
soil, thought to have been created by termites. These often support
distinctive plant communities.
The area has little agricultural potential due to the lack of water.
The paucity of grasses limits grazing, and the low carrying capacity
requires extensive supplementary feeds. Much soil has been lost
from the biome, through sheet eriosion, as a consequence of nearly
200 years of grazing. Ostrich farming, with considerable supplementary
feeding, is practised in the Little Karoo in the south of the biome.
In areas adjoining the Fynbos Biome, wine grapes, fruit and other
crops are cultivated using the Fynbos water catchments. Tourism
is a major industry: both the coastal scenery and the spring mass
flower displays are draw cards. Mining is important, especially
in the north.
Less than 0.5% of the area of the Succulent Karoo Biome has been
formally conserved. The biome has a high number of rare and Red
Data Book plant species. The high species richness and unique global
status of the biome require urgent conservation attention. Fortunately,
there are few invasive alien plants, with only Rooikrans Acacia
cyclops a major problem in the southern coastal regions. Strip-mining
for diamonds is destructive in the northern coastal regions, and
legislation requiring revegetation of these areas is inadequate
for near-desert conditions.