This biome comprises the Kaba Forest, Nonqausa Forest, Springmount Forest, Alexandria Bontveld and the inland Tootabie Forest.
The Tootabie Forest, comprising of tall evergreen trees with canopy heights varying from 10 – 15 m, with emergents of up to 20m (Van Wyk et al. 1988) occur in some valley bottoms and south-facing slopes in the moister areas of the Zuurberg. The Tootabie Forests are relatively isolated and therefore represent an important biogeographical link in the distribution of Afromontane forests in the eastern Cape and also between the eastern and southern Cape (Van Wyk et al. 1988).
The Kaba Forest is generally wetter, taller forest in the Alexandria coastal forests, limited to the wetter valley bottoms and south facing slopes. Found predominantly on limestone derived solid of the Nanaga formation, in the higher rainfall areas (750 – 850mm) in the coastal flats behind the primary dunes.
The Nonqausa Forest is generally a shorter version of the above, found in the drier areas (north facing slopes) and areas of decreased rainfall. Whilst the Springmount Forests found in the drier western areas of the Alexandria district is recognisable by a broken canopy of emergents.
The Alexandria Bontveld unit represents a transition zone between Nonqausa Forest and Grassland Biome, with discrete patches of grassland found on the taller hilltops and sometimes on the north facing slopes.
The Thicket Biome is characterised by dense thicket vegetation, with a broad range of plant growth forms (succulent, deciduous and evergreen shrubs, lianas, herbs, geophytes and grasses) and high diversity of woody shrubs and succulents. The phytogeographical origin of this vegetation is varied, and the plant communities are considered to be transitional in nature. This has led to a very high diversity, particularly of woody shrubs, but endemism is also high, particularly of geophytes and succulent forbs.
The Thicket Biome is under severe threat, particularly due to degradation through unsustainable pastoralism and other farming practices (Kerley et al. 1995). Nationally, 4.5 % are conserved, while the conservation status of the constituent land classes ranges from 1.8 to 14.5 %, which is generally below minimum of 10 %. Of particular concern is the fact that there are currently no areas of the unique Noorsveld (a subdivision of Xeric Succulent Thicket) conserved anywhere (Hilton-Taylor and Le Roux 1989). In addition, the Spekboomveld on the northern slopes of the Zuurberg (and not included in the current Addo Elephant national Park) differs significantly in terms of plant species composition from that south of the Zuurberg (Desmet and Ellis 1997).
The Mesic Thicket and the Xeric Thicket classes distinguish the Ticket Biome.
The Mesic Ticket has 15 land classes, namely the Wycombe Ticket, Boknes Thicket, Kromrivier Thicket, Ncanaha Thicket, Woody Cape Thicket, Enon Thicket, Olienhout Bontveld, Paterson Bontveld , Zuney Bontveld, Congoskraal Bontveld, Suurkop Bontveld, Coega Bontveld, Melkhoutboom Bontveld, Kruisrivier Bontveld and Colchester Strandveld.
This unit, found to the north of the Alexandria forest on Nanaga formation limestone derived soils, represents a transition zone between Nonqausa Forest and Kromrivier Thicket.
A mosaic of Woody Cape Thicket and Nonqausa Forest. The forest elements are generally found in the moister sites on the valley bottoms along river courses.
This unit is generally characterised by closed canopied (4 – 6m tall) stands dominated by non-succulent (succulent species are quite rare, other than Euphorbia triangular is), non-spiny species.
In contrast to the Coerney Spekboomveld, the plants in this unit are less spine scent.
9.Woody Cape Thicket
It is a non-succulent thicket type that occurs along the dunes, along the coastal strip. Here, this unit also includes Dune Forest, as these elements were too small to isolate. The unit is confined to the narrow strip seaward of the ancient dunes.
There is some degree of overlap in species between Enon thicket and Courtney Spekboomveld, but the abundance of the following species can generally be used as indicators of the unit: Aloe species, Euphorbia triangular is, Hippodromes pauciflorus, Pappea capensis (as opposed to Euclea undulata in Coerney Spekboomveld), Phyllanthus verrucosus, Ptaeroxylon obliquum and Schotia latifolia (as opposed to S. afra).
This unit is restricted to sites within the Nanaga formation where limestone is exposed or only covered by a shallow layer of sandy soils and Bokkeveld shales. It differs from the surrounding Savanna vegetation by lacking Acacia karoo.
This extensive unit is restricted to deep sandy soils of the Nanaga formation. The thicket clumps might be extensive where they occur in fire protected ravines in moister areas.
The Zuney Bontveld is found on calcareous sandstones derived from the Nanaga formation, and is dominated by woody plants with affinity to the Woody Cape Thicket, interspersed with strandveld species.
This unit is also restricted to the sandy soils of the Nananga formation. From the structurally similar Paterson Bontveld unit, it can be recognised in having a higher abundance of spinescent and succulent plants (e.g. Aloe africana, Azima tetracantha and occasionally also some Portulacaria afra) present in the thicket clumps.
Found in the Paterson district, on soils derived from the limestone of the Nanaga formation, this unit is in many respects similar to Coega Bontveld, but the thicket clumps are typical of wetter Enon Thicket, because the rainfall is higher.
Found on limestone outcrops, often as islands in a sea of thicket. Usually a mix of Fynbos, Grassland and Succulent Karoo elements.
Generally in small patches on lower north facing slopes, where the thicket has been heavily utilised (and perhaps burnt or bush cleared).
On sandy-loamy soils derived from sandstone, usually on the edge of extensive patches of Klein Winterhoek Grassy Fynbos.
A drier version of the Zuney Bontveld, comprising a scrubby mix of Woody Cape Thicket, Succulent Karoo and Strandveld species. Found close to the mouth of the Sundays River on finer estuarine alluvial soils, abutting the banks of the river, this unit supports a lower proportion of woody tree species than the Zuney Bontveld.
Whilst the Xeric Thicket comprises of ten land classes, namely the Kabouga Thicket, Coerney Spekboomveld, Vaalfontein Spekboomveld, Witrug Spekboomveld, Darlington Noorsveld, Ann’s Villa Noorsveld, Addo Bontveld, Kleinpoort Bontveld, Wapadskloof Bontveld and the Ongegund Bontveld.
Kabouga thicket is characterised by a high proportion of succulents and a high diversity in growth form, but is less spinescent than the thicket types found in the basin region (e.g. Coerney Spekboomveld). It is similar to Enon Thicket in species composition (especially the woody species), except that Portulacaria afra forms a more significant proportion of the canopy cover, particularly on the drier, steep, north facing slopes.
This unit supports a high proportion of succulents especially Secom. Secom tends to dominate entirely on the steeper north facing slopes.
Mostly limited to the Ripon Sandstone and Shale formation, with some of the mosaic formations found on Dwyka tillites. Generally, this unit is restricted to heavy clayey soils in the valley bottoms.
Where Spekboom (Portulacaria afra) is particularly dense, noors and Euphorbia bothae are generally displaced, particularly on hill slopes (mostly on north facing), where sandstone and tillite outcrops are exposed.
Witrug Spekboomveld differs from Darlington Noorsveld in that Portulacaria afra is found in high densities within this land class, particularly on north facing slopes.
Usually found on shallow (<1m) grey, clayey soils, which are often stony. The broad leafed, woody species, rarely form bushclumps and generally occur as individuals.
25.Ann’s Villa Noorsveld
When pristine, succulents are abundant. These areas would also support a number of palatable grasses. When degraded (overgrazed) the palatable grasses and most of the succulents are replaced by Aloe ferox, A. striata, Rhigozium obovatum and a number of other unpalatable shrubs.
On the deep, often red, loamy alluvial soils of the floodplain of the Sundays River. A rich grass (Eragrostis spp and Panicum spp.) component is well developed when pristine, but is usually reduced to Cynodon dactylon in heavily grazed areas.
The Karroid vegetation consists of a rich and unique combination of succulent and shrub species. When pristine, the grass component is well developed and consists of highly palatable species (e.g. Eustachys paspaloides and Themeda triandra), but this condition is now rare with less palatable species (Aristida diffusa) most common.
The karroid shrubland present is primarily restricted soils of the Witteberg, Ripon and Dwyka formations. In moist sites, such as south facing slopes, Renosterbos (Elytropappus rhinocerotis) may also be present, but it is never dominant. When pristine and especially after good rain, the grass component may be prominent, but this condition is now rare. The now present, and often dominant, karroid shrubs are probably secondary invaders, where the grass component (which replaced the thicket at cleared sites) has been overgrazed.
Found in the western portion of the study site, this unit consists of woody species of the Coerney Spekboomveld, which form bush-clumps within a mosaic of karroid vegetation.
The Fynbos Biome comprises the well-known heathlands of the south-western sector of South Africa. Fynbos is famous for its exceptionally high plant diversity (over 7000 species) and endemism (about 68 %).
This biome is divided into the following land classes: Zuurberg Proteoid Fynbos, Springvale Grassy Fynbos, Klein Winterhoek Grassy Fynbos and the Klipvlei Asteraceous Fynbos.
30.Zuurberg Proteoid Fynbos
Zuurberg Proteoid Fynbos is found primarily on the wet, steep to very steep south facing quarzitic sandstone slopes derived from the Rooirand Formation. Compared to the Grassy Fynbos elements, the cover of grass elements (largely C3 grasses) is fairly low.
31.Spring Vale Grassy Fynbos
Spring Vale Grassy Fynbos is found primarily in the moister regions of the eastern Zuurberg on the gently sloping south and east facing, quartzitic slopes on finer textured soils. In the south-eastern portions of the Zuurberg (east of the Sundays River) where mean annual rainfall is between 350-450mm, wet grassy fynbos is also found on the flatter ridge tops.
32.Klein Winterhoek Grassy Fynbos
Klein Winterhoek Grassy Fynbos is largely found on the gentle south facing slopes, on skeletal soils of quartzitic origins, in the drier western Zuurberg where mean annual rainfall is between 250-350mm, but does emerge onto the ridge tops to the north.
33.Klipvlei Asteraceous Fynbos
These dune scrub vegetation communities are generally characterised by the presence of Passerina rigida, Metalasia muricata, Helichrysum spp., Myrica chordifolia, Stenotaphrum secundatum and Chrysanthemoides monolifera. Furthermore, the communities with strong affinities to south Coast Dune Fynbos include Rapanea gilliana, Muraltia squarrosa, Ischyrolepis eleocharis, Agathosma ovata, Bonotea speciosa, Chironia baccifera. The dune pioneer communities, found in the less stabilised portions abutting the drift sands, include species such as Arctotheca populifolia, Carpobrotus edulis, Felicia echinata, Scaevola plumieri and Gazania rigens.
The Grassland Biome is characterised by a dominance of grasses, with few trees. Agriculture, pastoralism and human settlement are the major land-uses, resulting in extensive transformation of the habitat, and it has been shown that the Grassland Biome is the biome most in need of conservation (Rebelo 1997). The particular land class to be included in Addo National Park, Coastal Grassland, has only 11 % conserved, is limited to the Eastern Cape Province, and is under significant pressure from the development of coastal resort towns. The Grassland Biome is classified into the Round Hill Sour Grassland and the Modderfontein Shrubby Grassland.
34.Round Hill Sour Grassland
Found on north and west facing slopes on deeper shale derived soils. In the drier south-western portions of the Zuurberg, the grassland also tend to be found on the plateaus.
35.Modderfontein Shrubby Grassland
Generally found on the drier north facing quartzitic sandstone slopes of the western Zuurberg. A number of succulents are also found in varying degrees of abundance in the Modderfontein Shrubby Grassland e.g. Lampranthus spp.
Aloe ferox and Pteronia spp are often present in the more arid portions. Modderfontein Shrubby Grassland, which is also characterised by the absence of Restionaceae and Proteoids, is found mainly on the north facing slopes of the northern Zuurberg (from east to west); and in the western portions of the central and southern Zuurberg. Furthermore, in the drier south-western Zuurberg, it extends round to the south facing slopes.
The Nama Karoo Biome comprises the semi-arid, summer rainfall dwarf shrublands of the central plateau of South Africa. The Eastern Mixed Nama Karoo was considered by Acocks (1988) to be degraded of all vegetation types in South Africa. Paradoxically it also supports the highest diversity of plant species that Acocks recorded in the Karoo. None of the Central Lower Karoo veld type is formally conserved.
The Nama Karoo biome is classified into three land classes, namely the Crown Hill Broken Veld, Wolwefontein Pentziaveld and the Klipfontein Pentziaveld.
In the Crown Hill Broken Veld differs from the Wolwefontein Pentziaveld in that Eriocephalus africanus is more abundant, whilst Pentzia incana is less so. In these areas, the grass component would include Aristida congesta, Digitaria argyrograpta, D. ariantha amongst others.
A relatively dense, dwarf shrubland dominated by Pentzia incana and with subordinate cover of grasses, mainly species of Aristida, Eragrostis and Sporobolus.
This unit is found on poor, stony soils derived from the Ecca mudstones and sandstones, to the north east of Darlington Dam, in areas with rainfall of about 150 – 250mm a year. Many of the communities are rich in succulent plants. There is often a rich grass component, but only after good rains.
Azonal land classes
The azonal land classes include:
Two types of riparian woodland (Kirkwood Riparian Woodland and Waterford Riparian Woodland);
Algoa dunefield - this is the largest and least degraded in the world (Kerley and Boshoff 1997). It also acts as a surrogate for several key biological processes, and forms an important link between the terrestrial and marine environments. Key biological processes it supports include the maintenance of dune systems (e.g. erosion, stabilisation, succession), inland movement of marine sands producing gradients of soil development important for soil-specific plant assemblages and diversification of plant species, maintenance of nutrient-rich groundwater discharge that supports adjacent surf zone diatoms, which in turn drive the nutrient chain in the marine environment (Campbell and Bate 1991), and diurnal animal movement in and out of the dunefield.
Sundays Salt Marsh at the Sundays River mouth.
Acocks, JPH. 1988. Veld types of South Africa. Mem. Bot. Surv. S. Afr. 57: 1-128.
Desmet, P and Ellis, A. 1997. Brief assessment of the farm Modderfontein for inclusion into the Greater Addo Elephant National Park. Unpubl. Rep., Institute for Plant Conservation, Univ. of Cape Town.
Hilton-Taylor, C and Le Roux, A 1989. Conservation status of the fynbos and karoo biomes. In: Biotic diversity in Southern Africa: concepts and conservation. Huntley, BJ (ed.), Oxford University Press, Cape Town, pp 202 – 223.
Kerley, GIH, Knight, MH. and De Kock, M. 1995. Desertification of Subtropical Thicket in the Eastern Cape, South Africa: are there alternatives? Env. Monitor Assessment. 37:211-230.
Rebelo, AG. 1997. Conservation. In: Vegetation of Southern Africa, Lesotho and Swaziland. Dept. of Env. Affairs and Tourism, Pretoria, pp.1-85.
Van Wyk, BE, Novellie, PA and Van Wyk, CM. 1988. Flora of the Zuurberg National Park. 1. Characterization of major vegetation units. Bothalia 18: 211-220.