S. Afr. J. Bot.. 1995.61(1): 9-17 9 The grassland vegetation of the Low Drakensberg escarpment in the north-western KwaZulu-Natal and north-eastern Orange Free State border area C.M. Smit, G.J. Bredenkamp' and N. van Rooyen Department of Botany, University of Pretoria, 0002 Pretoria. Republic of South Africa Received: 17 Augll.u /99-1; revised I J October 1994 This study of the grasslands of the Low Drakenberg escarpment in the Newcastle-Meme] area forms part of the Grassland Biome Project. The 44 releves compiled in the Fa land type which represents the escarpment. were numer­ ically classified (TWINSPAN), and the results were refined by Braun-Blanquet procedures. The analyses revealed nine plant communities. A hierarchical classification, description and ecological interpretation of the nine plant communities are presented. Hi erdie ondersoek van die grasvelde van die Lae Drakensberg platorand in die Newcastle-Memel gebied maak deel uit van die Grasveldbioomprojek. Die 44 rei eves wat saamgestel is in die Fa landtipe wat die platorand verleen­ woordig, is numeries geklassifiseer (TWINSPAN) en die resultate is met behulp van Braun-Blanquet prosedures verfyn. Nege plantgemeenskappe is onderskei. 'n Hierargiese klassifikasie, beskrywing en ekologiese interpretasie van die nege plantgemeenskappe word aangebied. Keywords: Braun-8lanquet procedures, eastern escarpment, ecological in terpretation, Fa land type, grassland, vegetation classification . • To whom correspondence should be addressed. Introduction have been completed in the north-eastern Transvaal by Deall ct The Drakensberg Range forms part of the Great Escarpmenl at al. (1989) and Matthews et al. (1991. 1992a & 1992b). in the the eastern edge of the interi or plateau of southern Africa (Par­ eastern Oran ge Free State by Du Preez and Bredenkamp (1991), tridge & Maud 1987). The vegetation on the Low Drakensberg Du Preez et al. (1991) and Eckhardt et al. (1993a & 1993b). and escarpment in the Newcastle-Memel area (Figure 1) conforms to in KwaZulu-Natal by Smit et al. (1992. 1993a, 1993b & 1993c). Highland Sourveld (Acocks 1988) and Up lands Vegetation Generally. the vegetation within th e study area can broadly be (Edwards 1967), and forms part of the Afromontane Region divided into two di stinct types, namely grassland and woodland. (White 1978.1983). White (1983) indicated that this regi on con­ The woodland plant communit ies of the Fa land typl.! of the tains at least 4000 plant species, of which the remarkably hi gh escarpment were described by Smit et (It. (1993a) and were. in a proportion of 75% are endemic. Due to the complex origin and synthesis by Smit (1992), classified under Podocarpus l(llI/utitls evolutionary history of the Afromonlane flora, a strong plea for forest. In spite of these studies. little is known about the grass­ the preservation of the entire Afromontane flora was made by land plant communities of the escarpment arcas in the Newcas­ White (1981). Additi onally, the sources of many rivers are in tle- Memel area. Grassland vegetation is, however. of great the.«ie high-altitude catchment areas. Therefore, within a conser­ importance in these regions, as nearl y all of the 113 endemic vation frame of reference, the vegetation types of the eastern plant species recognized in the Wolkbcrg area of the eastern escarpment of southern Africa should have high priority, not only Transvaal escarpment are grassland-associated herbaceous plants because of the scenic beauty of the area (Dcall et ai. 1989), but (Matthews et al. 1993). This study aims to identify. classify, especially because of the high biodiversity and floristic richness describe and interpret ecologicall y the grassland communities of the endemic flora (Matthews et al. 1993; White 1983). On the fou nd on the Low Drakcnsberg escarpment. represented by the contrary, however, large parts of the southern African Afromon­ Fa land type (Land Type Survey Staff 1990) in th e Ncwcastle­ tane region are presently under considerable pressure due to Memel area (Figure I). development, especially by the timber industry (Matthews el al. 1993). In many parts. extensive afforestation has destroyed most Study area of the natural vegetation and alien trees have invaded large tracts This study formed part of a more extcnsive phytosociological of land . This is in direct connict with the need to protect moun­ survey of the Newcastle-Mcmel-Chelm sford Dam area (Smil tain catchmems. conserve natural ecosystems and preserve sce­ 1992). nic landscapes for the highly esteemed ecotourist industry (see The study area is situated between 27°33' and 28°00' S lati­ also Deall et ",. 1989). tude and 29°33' and 30°00' E longitude. representing the Grass­ Knowledge of the vegetation of a region forms the basis for land Biome in the border area of north-western KwaZulu-Natal understand ing and managing the natural resources and (he envi­ and north-eastern Orange Free State, South Africa. A detai led ronment, and rational land use planning is required to resolve description of the physical environment of the area was given by conflict between developers and conservationists (Ferrar et al. Smit (1992). The Fa land type comprises the principally cast­ 1988). Mentis and Huntley (1982) and Scheepers (1986) further­ facing escarpment of the Low Drakensberg at an altitude of more stated the necessity to identify and describe the major vege­ between 1530 and 1935 m. The position of the Fa land type tation types within the Grass land Biome of South Africa. This withi n the entire study area is indicated in Figure I. should clearly not only serve as inve ntori es but also as the sci en­ While not more than 15% of the land on the steep Drakensbcrg tific baseline for the development of resource managemcnt strat­ escarpment is arable (Land Type Survey Staff 1990), and due to egies. Within the escarpment area. phytosociological surveys the inaccessability of the terrain. th e land is mainly used for 10 S.-Afr.Tydskr.Plantk. 1995. 61(I) SCALE: ~O ______5~ ____~1~O ____~1~?~ __~~OKM Bb Land type Fa Land type ..........:::::::::::.. ~ Ad Land type EEITl............ Ea Land type ~ 1 :1Ac Land type CJ Ca Land type .::::;:r- Dra1nage lines Roads 1 :::::' 1Bd Land type -"-'" Natal IDE'S Border \I{,:.:~-.- '¥. Marshland Border of Study Area .. Ncandu Forest Reserve (e Zeekoeivlei Figure 1 Pusition of the land types in the Newcastle-Memel- Chelmsford Dam area. stock-farming. Exi sti ng conservational areas are the Natal Parks area by Smit (1992), the Fa land type consists mainly of the Board Ncandu Forest Reserve (Figure 1) where the Ncandu Lower Beaufort Stage (Visser & Bishopp 1976). Largely sand­ Ri ve r originates. and part of the farm Buffelshoek. which was stone , shale and mudstone of the Beaufort Group (provisionally proclaimed a natural heritage site and which hosts the Holkrans Estcourt Formation) occur here. with shale of the Volksrust For­ hiking trai l. mation (Ecca Group), as well as dolerite (Land Type Survey Staff 1990) present locally. Geology and topography The Fa land type refers to rugged hill s, ridges and steep moun­ According to the detailed description of the geology of the study tain slopes in which lime is rare or absent in the entire landscape S. Afr. J. Bot.. 1995.61(1) II (Land Type Survey Staff 1984). Most of it forms the escarpment approximation of the vegetation types of a particular area (Westhoff of the Low Drakensberg, incised by many streams and valleys. & Van der Maarel 1978; Behr & Bredenkamp 1988; Bredenkamp et Due to the steep and rugged terrain, the Fa land type is mainly of at. 1991). The semi-quantitative floristic data were therefore classi­ the multi phase terrain type (Land Type Survey Staff 1984). fied by TwINSPAN. These results were considered a first approxima­ Sheltered, moist valleys or ravines on the southern or south­ tion of the vegetation types of the area, and were then further refined eastern aspects arc often covered with temperate forest and asso­ by using Braun-Blanquet procedures. The results of TwINS PAN were ciated with permanent streams (Du Preez & Bredenkamp 1991; considered to be only preliminary. and are not discussed. The final Smit et al. 1993a), while the drier northern aspects and exposed results are presented in a phytosociological table (Table 1). ridges arc t:overed with grassland. Results and Discussion According to the Land Type Survey Staff (1990), the terrain types in the Fa land type in the study area arc all classified as DS . Classification 'D' means that less than 20% of the area has slopes less than 8% The grassland is classified as a Themeda triandm-Watsonia and '5' indicates local relief, and means that the difference lepida grassland with variations in vegetation associated with between the highest and lowest points in the landscape may vary slope, aspect, rockiness and degree of disturbance. A conspicu­ from 300 to 900 m. Sandstone cliffs are a common feature and ous difference between this grassland and the Themeda triandra­ where dolerite intruded, weather-resistant dolerite cliffs form the Monocymbium ceresiiforme Grassland of the B land type (Smit base for many spectacular waterfalls. er al. 1992). is the presence of the monocolyledonous geophyte, Walsonia lepida, in the former plant community. Soils The grassland communities were hierarchically classified as The predominant soil forms in the Fa land type arc Mispah and follows: Glenrosa. Due to the steep topography of the escarpment of the 1. The Themeda triandra-Watsonia lepida Grassland Low Drakensberg, it is described as a pedologic ally young land­ J .1 The Themeda triandra- Agapanrhus nutans Grassland scape that is not predominantly rock and not predominantly allu­ of steep, cool, non-rocky south-eastern aspects vial or aeolian. Rock weathering, the formation of orthic topsoil 1.2 The Themeda triandm-Rhus discolor Grassland on dry horizons and clay illuviation are the dominant soil-forming pro­ rocky north-western slopes on dolerite and sandstone cesses which have given rise to typically lithocutanic soil hori­ 1.3 The Themeda triandm-Monocymbium ceresiiforme zons (Land Type Survey Staff 1984; Van der Eyk et af.