Included here is the Great Karoo (or Nama Karoo) east of the Western Cape in South Africa and lying at the centre of the South African plateau (or meseta). It also extends over the Orange River into Namibia in the northwest. The Great Escarpment, which runs parallel to the coast 100 km to 200 km inland, divides it into two parts: one between 550 m to 900 m in elevation, the other between 900 and 1300 m.
Noorsveld
Dominated by the endemic grey, shrubby, stem succulent Euphorbia coerulescens (Euphorbiaceae) this veld type can be found as a wide belt along the sinuous middle section of the Sundays River Valley north of Grootriver Heights and Suurberg and centered on Jamsenville but with outliers occurring on the lower slopes of Great Winterhoek Mountains. The vegetation is named after noors the local name for euphorbias. Other shrubs include Aloe ferox, Capparis oleoides, Carissa haematocarpa, Euclea undulata, Grewia robusta, Lycium austrinum, Maytenus capitata, M. polyacantha, Nymania capensis, Pappea capensis, Portulacaria afra, Rhigozum obovatum, Rhus undulata and Schotia afra, although apart from the dark green Capparis oleoides, Lycium austrinum, Pappea capensis and Schotia afra most of these shrubs are fairly inconspicuous. In the often-bare patches between the shrubs are scatterings of species such as Eragrostis obtusa, Eriocephalus ericoides, Euphorbia ferox, Indigo sessilifolia, Mestoklema tuberosum, Pentzia incana, Phymaspermum pubescens and Selago triquetra. However, this veld type is often badly affected by over grazing. Among the less common components is the local endemic Euphorbia jansenvillensis (Euphobiaceae).
Spekboomveld
Named after the dominant species, named locally as spekboom (Portulacaria afra), this veld type can be found on steep sandstone quartzite and shale mountain slopes in the east and south Cape. It forms a dense scrub, which includes various succulent species. Common trees and shrubs include Crassula portulacea, Euclea undulata, Grewia robusta, Lycium austrinum, Pappea capensis, Rhigozum obovatum, Rhus lucida, R. longispina, Schotia afra and Tarchonanthus minor. Typical small plants comprise a variety of Crassula species such as C. cultrata, C. lycopioides, C. obvallata, C. perfoliata, C. perforata, C. rogersii, C. rupestris, C. tetragona together with Adromischus poellnitzianus, Cotyledon orbiculata, C. ramosissima, Cyphia sylvatica, Delosperma frutescens, Euphorbia mauritanica, Panicum maximum, Sansevieria thyrsiflora and Senecio junceus.
Bloomkoolganna Veld (Arid Karoo)
This veld type, named after bloomkoolganna the local name for the dominant and also poisonous Salsola tuberculata, is thought to be the climax vegetation of the Arid Karoo. This is the driest part of South Africa with rainfall ranging from just 50-200 mm a year. Most of the Arid Karoo is at an altitude of 900 m but the terrain is extremely flat except along the northern zone of the Roggeveld Mountains where it forms an undulating landscape across the valley of the Sak River. Along the edge of the Orange River it drops to an altitude of about 450 m. Bloomkoolganna Veld is best developed on sandy calcareous tufa mainly found on the northeast and northern borders of the Arid Karoo. It forms a fairly dense growth dominated by Salsola tuberculata and the grasses Stipagrostis ciliata and S. obtusa. Despite the dryness ground cover is surprisingly well developed with short grasses such as Enneapogon desvauxii, Eragrostis nindensis, Ovopetium capensis, Sporobolus lampranthus and Stipagrostis brevifolia predominating. The latter species is said to be the hardiest of all Arid Karoo plants – in severe draught it sheds its leaves and curls up into a yellow-brown ball and can survive when all other plants succumb. Annuals and geophytes are fairly abundant but not very conspicuous. Among the geophytes is the fern Ophiglosssum polyphyllum. Other typical species are Aptosimum spinescens, Dicoma capensis, Eriocephalus spinosus, Hermania spinosa, Lycium oxycladum, Nestleria humilis, Pentzia spinescens, Pteronia glomerata, Rhigozum trichotomum, Ruschia ferox, Salsola glabresens, Sarcocaulon patersonii and Zygophyllum microphyllum. Species of less general occurrence include Acanthopsis hoffmanseggiana, Aizoon schellenbergii, Aptosimum steingroeveri, Berkheya annectens, Geigeria ornativa, Limeum aethiopicum, Lycium arenicolum, Monechma desertorum, Osteospermum armatum, Peliostomum leucorrhizum, Pentzia pinnatisecta, Phaeoptilum spinosum, Plinthus karrooicus, Polygala seminuda, Pteronia leucoclada, Selago minutissima, Tribulus terrestris, Zygophyllum gilfillani and so on. Much of the veld type known as Central Upper Karoo (see below) has now been invaded by Arid Karoo elements due to disturbance from excessive grazing and in places this is now little different from Arid Karoo, and therefore known as False Arid Karoo.
Central Upper Karoo
This fairly distinctive veld type occurs on the central part of the upper plateau south of the Orange River at altitudes ranging from 1050-1700 m. The area is generally flat with stony plains but includes a scattering of dolerite hills. The principal shrub of the hills is Rhus undulata var. tricrenata, but grasses, particularly ‘white’ types such as Aristida congesta and Eragrostis lehmanniana, are also well represented. On the plains the vegetation generally becomes richer with the occasional patches of sand providing habitat for vegetation typified by Aristida diffusa and Eriocephalus ericoides, while the flood plains include shrubs such as Rhigozum trichotomum and various grasses. The only succulent to be regularly encountered is Ruschia ferox. At one time the poisonous perennial Geigeria ornative used to cause loss of stock but today this species is quite rare and largely restricted to depressions where extra water is available. Other more typical species include Asparagus stipulaceus, Chrysocoma tenuifolia, Drosanthemum lique, Eriocephalus pubescens, Felicia ovata, Gnidia polycephala, Homeria pura, Lightfootia tenella, Moraea polystachya, Nestleria humilis, Osteospermum leptolobum, Plinthus karooicus, Salsola rabieana and Tetrogonia arbuscula. One of the most catastrophic changes to South African vegetation has been the conversion of some 32,200 square km of grassveld in to what is now known as False Upper Karoo. As a result of excessive grazing due to the introduction of Merino sheep these areas are now little different from Central Upper Karoo apart from the fact that they are slightly grassier. Much of the sweet grassveld between Orange River and Sneeuwberg has now been converted to so-called False Upper Karoo.
Karoo Central Lower Karoo
This veld type has affinities with Arid Karoo, but situated at lower altitudes (700-1050 m) is not quite as arid. It occupies flat, stony terrain partly on calcareous tufa and partly on stony sandstone and shale. It tends to be shorter and denser than Arid Karoo sometimes having almost complete ground cover. Eberlanzia vulnerans, Pentzia incana and other succulents play an important role, while typical grasses include Stipagrostis ciliata and S. obtusa, both of which are characteristic of Arid Karoo. Other typical species include Aptosimum steingroeveri, Asaemia axillaris, Drosanthemum framesii, Eriocephalus spinescens, Felicia filifolia, Hermannia cuneifolia, Justicia orchioides, Lycium prunus-spinosa, Nestlera conferta, Osteospermum spinescens, Phymaspermum pubescens, Ruschia uncinella, Sphalmanthus tetragonu and Zygophyllum incrustatum. In this dense vegetation very few annuals occur but species of Galenia may be present.
Western Mountain Karoo
Mostly found on very stony terrain including granite, sandstone and shale, with a topography ranging from undulating to steeply rolling, this veld type can be divided into two sub-types. These are the Upper or Typical Form which merges with Central Upper Karoo in the Fraserberg area and extends westwards along the northern slopes of the Roggeveld Mountains and northwards along the Hantamsberg to the Loeriesfontein area, and the Lower or Semi-Succulent Form found at lower elevations in the more arid country along the southwestern foot of the Roggeveld Mountains between Calvinia and Nieuwoudtveld and north of Loeriesfontein. The upper form can grow to heights of up to one metre and is usually characterized by Pentzia incana except where excessive grazing occurs. Perennial grasses, with the exception of Ehrhartia calycina and to a lesser extent Merxmuellera stricta, are scarce. Other typical species include Aloinopsis malherbei, Asparagus capensis, Cotyledon wallichii, Drosanthemum ambiguum, Euphorbia multiceps, Galenia fruticosa, Hirpicium alienatum, Lightfootia thunbergiana, Nestlera prostrata, Osteospermum sinuatum, Pteronia glauca, Ruschia tuberculosa, Salvia rugosa and Zygophyllum gilfillanii. The lower or semi-succulent form has many species in common with the upper form despite its lower stature, but differs in that mesembryanthemums are much more common. Examples include Aridaria calycina, Brownanthus ciliatus, Drosanthemum eburneum, Lampranthus watermeyeri, Leipoldtia constricta, Malephora framesii, Mesembryanthemum annuum, Psilocaulon utile and Ruschia pumila.
Orange River Broken Veld
This veld type can be divided into three sub-types. The more typical type is characterized by Aloe dichotoma and Euphorbia avasmontana. It occurs on steep rocky mountains between Prieska and Kakamas. The second type, largely dominated by Rhigozum trichotomum, occurs on gravel and stony plains; while the third type is predominantly Acacia mellifera subsp. detinens extends up the valleys of the Vaal-Hartz and Orange River valleys. However, only the typical veld type will be described here. It occurs on various rock types including banded ironstone, dolomite, quartzite and granite at altitudes ranging from 750-1350 m. Other typical trees and shrubs include Acacia mellifera, A. karoo, Boscia albitrunca, Lycium austrinum, Ehretia rigida, Phaeoptilum spinosum, Rhigozum trichotomum, R. obovatum, Sarcostemma viminale and Ziziphus mucronata. Among the many smaller plants are Aizoon burchelii, Barleria tigida, Corbichonia decumbens, Dicoma capensis, Euryops multifidus, Felicia muricata, Garuleum schinzii, Helichrysum lucilioides, Indigofera sessilifolia, Lasiocorys capensis, Osteospermum microphyllum, Pachypodium succulentum, Rogeria longiflora, Senecio longiflorus, Talinum caffrum and Zygophyllum suffrutocosum.
Karroid Broken Veld
Characteristic of very arid, stony places virtually devoid of soil this veld type includes a variety of stunted shrubs, and to make matters worse these areas experience the phenomenon known as ‘dry rain’ (wisps of precipitation evaporating before reaching the ground). The principal shrubs include Chrysocoma tenuifolia, Delosperma subincanum, Dicoma spinosa, Drosanthemum framesii, Eriocephalus spinescens, Euphorbia arida, Felicia filifolia, Galenia fruticosa, Garuleum bipinnatum, Helichrysum lucilioides, Hermannia cuneifolia, Lasiosiphon meisnerianus, Lebeckia spinescens, Limeum aethiopicum, Microloma massonii, Monechma pseudopatulum, Osteospermum sinuatum, Pentzia spinnescens, Polygala seminuda, Pteronia adenocarpa, Salsola rabieana, Sarcocaulon patersonii, Sericocoma avolans, Tetragonia fruticosa, Trianthema triquetra, Trichodiadema barbatum and Zygophyllum microphyllum. Some of the principal grasses are Aristida diffusa, Cenchrus ciliaris, Digitaria argyrograpta Enneapogon scaber, Eragrostis obtusa, Fingerhuthia africana, Heteropogon contortus, Oropetium capense, Sporobolus fimbriatus, Stipagrostis obtusa, Themeda triandra and Tragus koelerioides.
Northern Bushmanland Succulent Karoo
In contrast to the barren plains, the mountains and crags of northern Bushmanland support pockets of succulent karoo-type vegetation. These are found on cool, south-facing slopes where there is a decree of winter precipitation. In fact, the higher mountains (above 1000 m) can be shrouded in cloud during winter. Mesembryanthemums and asteraceous shrubs predominate. Characteristic succulents include Andromischus marianiae, Antimima vanzylii, Crassula saxifraga, Drosanthemum godmaniae, Ruschia cradockensis, Scleiiont toriuosum, Tylecodon paniculaius and so on. The associated non-succulent shrubs are typical of rock outcrops in Namaqualand. These include Anthospermum spalhulatum, Eriocephalus microphyllus, Penzia argeniea and Stachys rugosa. Among the local endemics is Abutilon pycnodon (Malvaceae), Aloe dabenorisana (Aloaceae), Antherothamnus personii (Scrophulariaceae), Bowiea gariepensis (Hyacinthaceae), Jatropha orangeana (Euphorbiaceae), Commiphora gracilifrondosa (Burseraceae), Diospyros acocksii (Ebenaceae), Ointeranthus micropsermus (family?), Ruschia barnardii (Aizoaceae) and Salvia gariepensis (Lamiaceae). However, it has been suggested that this succulent vegetation should be regarded as outliers of the Succulent Karroo biome rather than part of the Nama Karoo.
Felicia filifolia-Themeda triandra Mesa Formation
Studies on the Falminkskop and Tafelberg mesas in South Africa’s Middelburg district of the Nama Karoo show that parts of these support shrubby grassland characterized by Felicia filifolia and Themeda triandra. Unlike the surrounding plains this vegetation shows little impact from domestic herbivory and therefore much more natural. In contrast to the plains palatable species are common or dominant while unpalatable species generally occur at low densities. Three sub-association or communities has been recognized. On the Tafelberg plateau the vegetation is described as a Felicia filifolia – Dimorphotheca cuneata community, on the Falminkskop plateau a Felicia filifolia – Enneopogon scoparius community and on the southeast slopes of Tafelberg a Felicia filifolia – Eriocephalus africanus community. The most species-rich of these is the Felicia filifolia – Dimorphotheca cuneata community on Tafelberg. Here other species include Berkheya pinnatifida, Bulbine frutescens, Commelina africana, Dianthus bascuticus, Diospyros austro-africana, Grassula orbicularis, Kedrostis africana, Ruschia britteniae, Moraea pallida, Panicum maximum, Selago saxatilis and Sutera halimifolia.
Rhigozum obovatum-Rhus burchellii Mesa Formation
Grassy tall shrubland characterized by Rhigozum obovatum and Rhus burchellii can be found on the slopes of Falminkskop, Buffelskop and Talfelberg meses and on the Buffelskop plateau. The impact of domestic grazing on this vegetation ranges from negligible to high. Three sub-association or communities have been recognized but only the Rhigozum obovatum – Gymosporia buxifolia community is largely free from domestic herbivory. Palatable species are common to dominant and this vegetation can be regarded as near natural. It is found on all three mesas in places where there is limited access for domestic stock. Associated species include Blepharis mitrata, Crassula lanuginosa, Enneapogon desvauxii, Euphorbia brachiata, Fingerhuthia africana, Hermannia minutiflora, Indigastrum parviflorum, Indigofera sessilifolia, Lessertia carnosa, Pellaea calomelanos, Polygala ephedroides and Zygophyllum lichtensteinianum.
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