Thicket types:

Dune thicketValley ThicketXeric Succulent ThicketMesic Succulent Thicket Spekboom Succulent Thicket

6. XERIC SUCCULENT THICKET

Synonym:

Xeric Succulent Thicket

Valley Bushveld (A23).

Statistics:

8 408 km²; ± 51% transformed; 8.01% conserved.

Locality & Physical Geography.

This succulent thicket occurs mainly in dry areas of the Fish and Sundays River valleys.

Climate:

Rainfall in these hot, dry valley basins is 300 to 450 mm per year and temperatures range from 0 to greater than 40C with a mean of 18C. Valley mists are common.

Geology & Soil:

Soils are deep lime-rich, sandy loams or solonetic soils derived from the Uitenhage and Ecca Group shales.

Vegetation:

There is a high proportion of succulents and the flora is transitional from Tongaland-Pondoland to Karoo-Namibian. It includes leaf- and stem-succulent shrubs, trees and lianas and small- and large-leaved sclerophyllous shrubs and trees, succulent herbs, grasses and forbs. This low, relatively sparse thicket has a shrub canopy 2 to 2.5 m in height. The number of succulents and endemics is high, although species richness is low compared to other thicket types. Characteristic woody species are Karoo Cross-berry Grewia robusta, Small Bitterleaf Brachylaena ilicifolia, Maytenus capitata and Lycium campanulatum. Succulent species include Sweet Noorsdoring Euphorbia coerulescens, Spekboom Portulacaria afra and Euphorbia bothae. There are few herbs and grasses such as Anchorkaroo Pentzia incana, Bitterbush Chrysocoma ciliata and Couchgrass Cynodon dactylon.

Key Environmental Parameters:

Plants obtain their moisture from valley mists in the drier regions. Xeric Succulent Thicket, like Valley Thicket, is invasive into savanna and grassland. The lack of large browsers, such as rhino and kudu, to contain the larger plants is resulting in its now spreading into neighbouring vegetation types.

Economic Uses:

Goat farming is the major activity, with some ostrich farming. Along the rivers, lands are under irrigation for lucerne and other crops, and orange orchards occur in the Addo region.

Conservation Status:

It is under threat where there is intensive, poorly managed farming with goats or ostriches. It is represented in the Addo Elephant National Park.

Key Reference:

Everard (1987).

Author.

Roy Lubke.