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Sovth Af11can Jovnml of Botany 2001 67 26 t-273 . .._l?.f!Y!~9/Jt If> N/SC Pty Lid-· . Prmteel m Sovt/J Afrrc,, - All 11gh/s rcsoiVOCI SOUTH AfRI CAN JOURNAL OF BOTANY ISSN 0254- 6299 Conservation of the Vegetation on the Melville Ridge, Johannesburg WN Ellery', K Balkwill2*, K Ellery' and RA Reddy2 ' School of Environmental Sciences, University of Natal, Private Bag X10, Dalbridge 4014, South Africa .. Department of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag X3, Wits 2050, South Africa ·Corresponding authour. e-mail: [email protected] Received 8 November 1999, accepted in revised form 24 October 2000 The Melville Koppies Ridge in Johannesburg is an area subject to contrasting management histories, with the of natural wilderness within the urban environment. The Melville Koppies Nature Reserve having strictly con­ aim of the study was to establish the relationship trolled and limited access and exclusion of fire, while between vegetation distribution and environmental con­ access to the eastward and westward extensions of the ditions on the ridge, as well as to determine the impacts reserve were not controlled at all. This has led to the of management on vegetation distribution. The ridge development of new vegetation communities in the has had a long history of settlement and disturbance, reserve, but higher diversity in the uncontrolled area. but the vegetation on the ridge is surprisingly species Thus, clear conservation objectives are required to rich, with little evidence of former disturbance. Over the guide management. past three decades, vegetation on the ridge has been Introduction The presence of natural wilderness within the urban envi­ natural environment has been greatly disturbed. Attempts ronment is being increasingly recognised as a valuable are being made to manage the vegetation along the entire alternative to the more typical manicured, formal garden that ridge for conservation and recreation, with the primary characterises most cities around the world (Poynton and objective being to maintain the vegetation in as natural a Roberts 1985). These wilderness areas offer the same state as possible. opportunities for recreation and relaxation as do formal gar­ The Melville Ridge provides an interesting contrast of dens, but they also offer opportunities for conservation and management approaches. MKNR itself has been used for education that extend beyond that which more conventional educational purposes on ly, with access limited to the gener­ parks and gardens offer. However, conservation of natural al public on a small number of days during the summer wilderness within the urban environment poses particular months as well as to a few individuals belonging to conser­ problems for migration, the free exchange of genetic materi­ vation and/or educational institutions. Burning within MKNR al, and the survival of small populations of plants and ani­ has been controlled, and excluded as far as possible. In con­ mals. The theory of island biogeography, and its extension, trast the SEP is freely accessible to the general public, and reticular biogeography, are considered to offer a theoretical has had a history of use by the African Independent framework on which overall planning can be based (Poynton Churches, who worship in large numbers on Sundays, each and Roberts 1985). However. at the local scale, manage­ congregation of several dozen worshippers meeting at a ment should focus on meeting particular objectives, and designated site in th e open air. In order to prevent soil ero­ these need to be appropriately addressed by the urban sion church members keep paths in a good state of repair, authority charged with management of open spaces in the and meet on concrete slabs that they have laid themselves urban environment. in amongst the natural vegetation. The LGVS, also an open The Melville Ridge, including the Melville Koppies Nature access area, is not used formally by any group, although Reserve (MKNR) and its eastward and westward exten­ there are several paths crossing it. Fires occur regularly (at sions, the Sima Eliovson Park (SEP) and Louw Geldenhuys intervals of between 2 and 3 years) in both the SEP and Vi ew Site (LGVS) respectively, represent some of the most LGVS as a result of accidental ignitions. This contrasting interesting and diverse natural vegetation of the land use and fire regime within an area of similar climate and Witwatersrand Ridge. The area has a history of settlement geology, provides an ideal opportunity to compare the by both Stone Age as well as I ron Age Peoples (Mason impacts of different management approaches. 1984 ). It is in the largest city in the country, one in which the The aim of this study was to establish the relationship 262 Ellery. Balkwill, Ellery and Reddy between vegetation distribution and environmental condi­ Rocky Highveld Grassland (Bredenkamp and Van Rooyen tions, and furthermore, to determine the impacts of man­ 1996). The vegetation is described as being predominantly agement on vegetation distribution. grassland with many dicotyledonous forbs. Woody vegeta­ tion of Zambezian and Afromontane affinities occurs in shel­ Study Area tered islands, where the vegetation is described as 'temper­ ate mountain bushveld within the Grassland Biome' by these Locality and Climate authors. The conservation status of this vegetation type is poor and The study area is situated along the Witwatersrand ridge in continues to be threatened by urbanisation, industrial the Johannesburg suburbs of Melville and Westdene. It expansion and agriculture (Bredenkamp and Van Rooyen occupies an area of approximately 1 .6km~. covering a dis­ 1996). The Melville Koppies and its extension represent a tance of 4km and with an average width of just 0.4km. As sincere attempt by the City of Johannesburg to conserve such it is a linear feature with a high edge to area ratio. The remnants of this vegetation type within the urban setting. altitude of the study area varies between 1 680 and 1 740m. The climate of Johannesburg can be described as tem­ Geology perate with warm, wet summers and cool, dry winters. Average daily temperatures in December and January are The geology of MKNR (Figure 1) has been described and between 19 and 20°C, and in June and July between 9 and mapped by Van Biljoen (1984). The area comprises a sedi­ 1ooc (Weather Bureau 1986). Average daily maximum tem­ mentary sequence at the base of the Witwatersrand peratures in December and January are approximately Supergroup, overlying diorite which occurs in the north of 26°C, while average daily minimum temperatures in June the study area. The sedimentary sequence exposed in the and July are approximately 2°C. Frost is common in mid­ southern half of the study area is part of the Hospital Hill winter. series, comprising a number of layers of shale and slate, Rainfall typically occurs in the form of short, intense thun­ which occur between layers of quartzite. The entire derstorms, averaging approximately 700mm per annum, of sequence has been tilted, with strata dipping towards the which 80% occurs in the summer months from October to south (Figure 2). March (Weather Bureau 1986). Quartzite is extremely resistant to weathering and erosion, and forms the rocky ridges that run from east to west along Vegetation and its conservation status th e entire study area. By creating ridges of prominent relief they make the area scenically attractive. Soils on the The study area is in the grassland biome which is dominat­ quartzite are virtually non-existent, extremely acid, and of ed by a single stratum of vegetation, herbaceous plants that extremely low nutrien t status, particularly those on slopes have their perennating organs close to ground level with a southern aspect that occur on the former contact sur­ (Rutherford and Westfall 1994) . Vegetation of the area is faces between th e quartzite and the shales and slates. Shales. slates and granites are more prone to weathering, and these occupy the depressions between the rocky 28' 00' E quartzite ridges. The soils derived from slates, shales and LEGEND s N Shale t.;;::I +----Study area ---~ 1?2] Ouartzile ~Diorote c:::J Alluvium B Stonowall c:::J Dlabaso [I[] Smalling lurnaco D Shale [I] Iron ore o.xposur o c:::J Ouartzlto D oto~ to c::::;:] Quartz volns l Figure 1: Geology of the Melville Koppies Nature reserve (after Van Figure 2: Geological cross-section of the lower Witwatersrand Biljoen 1984) and distribution of Iron Age settlement sites (after Supergroup showing the stratigraphy and dip of sedimentary strata. Mason 1984) and the location of the study site in relation to rock outcrops South Afncan Journal of Botany 2001. 67 161- 168 263 granites are better developed than on the quartzite. but are habit, growth form, life history strategy, habitat and origin nevertheless shallow and somewhat skeletal. They are more (i.e. whether foreign or indigenous) for each taxon on the basic and potentially have a higher nutrient status than the Computerised Herbarium Management System of the CE quartzite, giving rise to soils of intermediate fertility. Moss Herbarium on a species by species basis. The classi­ fication presented in Table 2 was used; trees were differen­ History tiated from shrubs on the basis of having a South African tree number. Habitat was classified into grassland, wood­ The prehistoric people of MKNR are described by Mason land and forest on the basis of notes made on herbarium (1984}. The area of MKNR has been inhabited by Stone Age labels. The checklist was compared to the list of southern as well as Iron Age Peoples. Their presence is indicated by African plants and their distributions (Arnold and De Wet the discovery of stone artifacts (Stone Age}, as well as of 1993) and to the Red Data List (Hilton-Taylor 1996} to deter­ stone walls, iron furnaces, iron implements and pottery (Iron mine whether any were endemic to the former Transvaal Age}.

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