Nama Karoo types:

Bushmanland Nama KarooUpper Nama KarooOrange River Nama Karoo Eastern Mixed Nama KarooGreat Nama KarooCentral Lower Nama Karoo

54. CENTRAL LOWER NAMA KAROO

Synonyms:

Central Lower Nama Karoo

Karroid Broken Veld (A26), Central Lower Karoo (A30), Steytlerville Karoo (A31b).

Statistics:

24 727 km²; area transformed unknown; 0.04% conserved.

Locality & Physical Geography:

This region incorporates the eastern part of the large flat basin lying between the escarpment to the north and the mountains of the Cape Fold Belt to the south. While altitude and rainfall patterns are similar, the soils of this region are not everywhere as shallow and stony as in the Great Nama Karoo.

Climate:

Rainfall of about 150 to 250 mm per year is low and occurs mostly in autumn. The Central Lower Nama Karoo lies in the rainshadow of the Great Escarpment to the north but obtains some cyclonic rain from the south-east.

Geology & Soil:

The Beaufort Group shales and sandstones give rise to poor stony soils, which are slightly deeper than those of the Great Nama Karoo.

Vegetation:

Although sharing many dwarf shrubs with the Great Nama Karoo, such as Rhigozum obovatum and Anchorkaroo Pentzia incana, this vegetation type has a considerably greater incidence of succulent plants such as Delosperma spp., Thorn Vygie Eberlanzia ferox, Ruschia spp. and Noorsdoring Euphorbia ferox. Grasses only occur in abundance following good summer rains and then species such as Lehmann's Lovegrass Eragrostis lehmanniana, Aristida spp. and Digitaria spp. are common. Sweet Thorn Acacia karroo is an important tree of the dry river beds.

Key Environmental Parameters:

This vegetation type receives sporadic winter rains derived from frontal systems, as well as summer thundershowers. This results in a relatively high incidence of both succulent shrubs and summer-rainfall grasses. Plant cover is generally higher than in the Great Nama Karoo to the west, which has a lower rainfall. Frosts occur frequently.

Economic Uses:

Mainly grazing by small stock including Angora and Boer Goats, Merino and Dorper Sheep.

Conservation Status:

Very poor. Several reserves occur in this vegetation type, but their area is small. The Central Lower Nama Karoo has been heavily grazed since the 1770's when Europeans first colonized the area. Although its has been degraded as a consequence, the effect of overgrazing is largely reversible and careful farming can restore the vegetation cover. The effects of overgrazing can easily be seen along fence-lines between neighbouring farms.

Key Reference:

Acocks (1988).

Author:

Timm Hoffman.