LEGEND
2.7. FLORA
The vegetationof South Africa was studied and mapped bylP.H.Acocks and the publication in 1953 of 'Veld types of South Africa', which included a vegetation map followed. Acocks mapped and described the vegetation of South Africa in terms of the agricultural potential of the vegetation, whereas the map should have rather been structured for more than agricultural planning. Since Acocks's work approaches to and concepts in vegetation classification have changed markedly and a considerable amount of new information has been collected. These shortcomings, as well as there having been no new or updated maps of the vegetation of South Africa since 1953, lead to Low & Rebelo (1996) producing a vegetation map and guide of South Africa, Lesotho and Swaziland. Low & Rebelo (1996) described and mapped four vegetation types, which lie within the Karkloof Catchment (Figure 2.8. (p.21)). These vegetation types are units of vegetation, which would have occurred today, were it not for man-made transformations.The four vegetation types are:
1. 'Afromontane Forest' (plate 5. (p.33)).This extends along the KarkloofRange from west to east and southwards along the eastern boundary ofthe catchment.Itoccurs on south-facing ridges and in ravines where moisture is higher and the maximum effect of the south-westerly and south-easterly wind-driven rains is apparent. Itissignificant that the KarkloofForest occurs almost precisely along the delineated west to east extent of 'Afromontane Forest' in the catchment. The area also receives considerable rainfall (1152 mm mean annual rainfall), which is a requirement of 'Afromontane Forest' distribution. It is thought that the 'Afromontane Forest' would certainly spread into grasslands were it not for fires. The majority of the KarkloofForest in fact occurs in habitats relatively safe from fires such as on steep slopes.
Trees can be up to 30 m or 40 m tall and distinct strata of emergent trees, canopy trees, shrub and herb layers are present.
Tree species include: Podocarpus latifolius, P. falcatus, Trichocladus ellipticus, Rhus chirendensis, Curtisia dentata, Calodendrum capense, Apodytes dimidiata, Halleria lucida, Ilex mitis, Kiggelaria africana, Nuxia floribunda, Xymalos monospora, Rapanea melanophloeos and Ocotea bullata. Shrub and Climber species include: Maytenus heterophylla, Scutia myrtina, Carissa bispinosa, Secamone alpinii, Canthium ciliatum, Rhoicissus tridentata,Zanthophyllum capenseandBurchellia bubalina.Typical grasses, herbs and ferns include: Oplismenus hirtellus, Stipa dregeana, Centella asiatica, Cyperus albostriatus, Polypodium polypodioides, Polystichum luctuosum, Streptocarpus rexii and Plectranthusspp. Approximately 16.4% (of792 knr') of'Afromontane Forest' in KwaZulu- Natal and 17.6% (of 5877 km') in southern Africa is conserved.Levels are deemed as having the status of 'well conserved'.
Cooper (1985) undertook a survey of the conservation status of indigenous forests in the former Provinces of Transvaal, Natal and Orange Free State of South Africa.He classified the KarkloofForest as an example of 'Afromontane Forest' of the sub-type, 'Mist Belt Mixed Podocarpus Forest'. Especially relevant is Cooper's (1985) comment that the KarkloofForest is by far the most important private forest in the 'Mist Belt Mixed Podocarpus Forest' category.
He consideredit important not just for its size, but also because it afforded a suitable habitat for numerous birds, animals and plant species, which were listed as rare, threatened or endangered in South Africa. Cooper (1985) recommended that the forest and adjoining grassland should constitute one of the top conservation priorities for KwaZulu-Natal. A preliminary checklist of plants (Appendix 2. (p.B7») occurring on the farm 'Ehlatini', located in the KarkloofForest was prepared (Cooper& Moll 1967). Although the list was prepared only for 'Ehlatini', species cited in the list may be said to be representative of the greater KarkloofForest.
2. 'Moist Upland Grassland' (plate 6. (p.33». This extends throughout most ofthe catchment, but is more extensive towards the north-west in the vicinity of the farms 'Sherwood' and 'Weltevreden', and to the north-east along the KarkloofRange to Mount Gilboa.'Afromontane Forest' is scattered within the grassland. The climatic requirements of this vegetation type include:mean annual rainfall between 650 mm to 1000 mm, and mean annual temperatures between _3°C to 40 °c, with an average of 16°C.
This vegetation type is often evident on disturbed, ploughed or heavily overgrazed and degraded sites, indicating the secondary status of many of the representative plant communities. Poor grazing management of these grasslands encourages an increase of unpalatable grasses, such asAristida junciformisand the invasion of herbaceous weeds.The vegetation type may be termed, 'sourveld'. Scott (1947) states that in sourveld the majority ofthe grasses become unpalatable for livestock on reaching maturity. Palatable material is thus only available during the growing season.This has limitations for livestock grazing and production within the area.
Dominant grass species include: Themeda triandra (high to very high grazing value), Heteropogon contortus(average to high grazing value), Tristachyaleucothrix(variable grazing value), Eragrostis curvula (average grazing value under natural conditions) and Elionurus muticus (very low grazing value). Grazing value stated is that assessed by van Oudtshoom (1992). Diagnostic herbaceous species include: Walafrida densiflora, Cucumiszeyheri, C.
hirsutus, Berkheya onopordifolia, Spermacoce natalensis, Kohautia cynanchica, Tephrosia macropoda, T. multijunga, Conyza obscura, Corchorus confusus,Phyllanthus glaucophyllus, Richardia brasiliensis, Gomphrena celosioides, Aster bakerianus, Alysicarpus rugosus, Helichrysum coriaceum and H. rugulosum. Tree and shrub species include: Maytenus heterophylla, Zanthoxylum capense, Ziziphus mucronata, Rhus rehmanniana and Acacia sieberiana. These occur on sheltered sites, rocky hills and ridges. Approximately 7.5% (of 13800 knr') of 'Moist Upland Grassland' in KwaZulu-Natal and 2.5% (of 44012 km') in southern Africa is conserved.Levels are deemed as having the status of 'poorly conserved'. In fact only one large significant remnant patch of this grassland type occurs on the farm 'Sherwood' in the north-west of the catchment. Small scattered remnant patches also occur, mainly near the KarkloofForest and at Mount Gilboa.Much of the 'Moist Upland Grassland' which would have occurred today in the Karkloof Catchment, has been destroyed largely by exotic afforestation.
3. 'Short Mistbelt Grassland'. This extends across the remainder of the catchment to the south. The vegetation is dense Themeda triandra dominated grassland.Aristida junciformis is dominant in areas disturbed by intensive agriculture. The climatic requirements of this vegetationtype include mean annual rainfall between 900 mm to 1200mm,and mean annual temperatures between -2 GC to 38 GC,with an average of 17 GC.
Dominant grass species include:Monocymbium ceresiiforme (low grazing value), Trachypogon spicatus (average to low grazing value), Tristachya leucothrix (variable grazing value), Eragrostis racemosa (low grazing value) and Diheteropogon amplectens (average to high grazing value). Grazing value stated is that assessed by van Oudtshoorn (1992).Approximately 2.5%(of 4537krrr') of 'Short Mistbelt Grassland' in KwaZulu-Natal and 2.4% (of 4814km2)
in southern Africa is conserved. Levels are deemed as having the status of'poorly conserved'.
Conservation status is lower than that of the 'Moist Upland Grassland' type. Much of the 'Short Mistbelt Grassland' which would have occurred today in the KarkloofCatchment, has been replaced by intensive cultivation and exotic afforestation.
4. Small sections of 'North-eastern Mountain Grassland' are shown to extend slightly into the catchment towards the north-west and south-east.This grassland contains many endemic plant species. Approximately 3.9% (of 10 968 krrr')of 'North-eastern Mountain Grassland' in KwaZulu-Natal and 7.4% (of 41 905 km') in southern Africa is conserved. In the Karldoof Catchment,limited small isolated patches of this vegetation type remain.This may be attributed to the small sections, which would have occurred in the catchment and the destruction of these areas by the establishment of exotic afforestation.
The poor conservation status of the grasslands in the Karldoof Catchment is a cause for concern. Such poor status is further exacerbated because although fragmented pockets of the grassland types still remain, the condition of many of these, especially in terms of palatable grass species composition, is poor.Thus its conservation status is far more threatened than is spatially shown.Itis further estimated by Scott-Shaw (1999) that well over 90% of Acocks's (1988) Veld Type, 'Natal Mistbelt Ngongoni Veld (45)',into which category the grasslands of the KarldoofCatchment fall, has been transformed, with only 0.3% protected (proclaimed Protected Areas). Scott-Shaw (1999) rated the Veld Type as being one of the most threatened Veld Types in KwaZulu-Natal, stating that a disproportionately high number of threatened plants occur in only a few Veld Types which typically have high rainfallsand mild temperatures.
Such environments also attract intensive crop farming and habitation.