Bergwind Botanical Surveys & Tours CC

Botanical Assessment
of site for proposed Life Sciences Building at the University of the Western Cape, Bellville,
City of Cape Town

Report by Dr David J. McDonald

Bergwind Botanical Surveys & Tours CC.

14A Thomson Road, Claremont, 7708

Tel / Fax: 021-671-4056

University of the Western Cape: Botanical Assessment of site for New Life Sciences Building

1. Introduction

The botanical assessment covered in this report was commissioned by the University of the Western Cape, Bellville (UWC). UWC proposes to develop a tract of land of 0.89 ha within the University precinct for the purposes of constructing a new Life Sciences building. The botanical evaluation of the site forms part of an environmental sensitivity assessment that is necessary because the site is on deep sands that supports Sand Fynbos. This vegetation type has been heavily impacted by development on the Cape Flats – where UWC is situated – and elsewhere. This report examines the state of the site of the proposed development in terms of its botanical attributes and the future of the Cape Flats Sand Fynbos in the designated area in the light of the proposed development. The recommended guidelines for specialist studies of this nature (Brownlie 2005, De Villiers et al. 2005) have been followed.

2. Terms of Reference

ø To examine and record the vegetation of the proposed development site for a new Life Sciences complex at UWC.

ø To look for any sensitive habitats and rare or endangered plant species that should be avoided or that may require ‘search and rescue’ interventions should the development proceed on the proposed site and the habitat be unavoidably impacted by the proposed development.

ø To identify ‘no go’ zones and areas of opportunities and constraints from a botanical perspective.

ø To provide recommendations re mitigation for any negative impacts on the natural vegetation at the site.

3. Study Area

3.1 Site description, location and history

The site under investigation is situated on the Cape Flats within the property of the University of the Western Cape (Figures 1 & 2). It is currently an undeveloped portion of land that has a ‘dog-leg’ shape. It is closely adjacent to Modderdam Road on its western boundary whereas to the north it is bordered by a UWC parking area and to the east prefabricated buildings and the precinct where the security dogs are housed. The southern boundary is a fence that separates the site from another portion of vacant land forming part of the Senate House area.

Figure 1. Location of the University of the Western Cape (UWC) on the Cape Flats in relation to Cape Town.

The Cape Flats Nature Reserve (CFNR) (Figure 2) is on the campus of the UWC but is specifically set aside for the conservation of plant and faunal communities typical of the sandy Cape Flats. It was officially proclaimed in 1977 under Section 12(4) of the Nature Conservation Ordinance of 1974 and was declared a National Monument in 1978. It serves for experimental and research work and environmental education (Low 1986).

This study is confined to the ‘dog’s leg’ area (Figure 2) that has been managed as part of the CFNR but which is not formally part of the proclaimed CFNR as surveyed and recognized by the UWC Planning Department. The ‘dog’s leg’ has been part of discussions and memoranda concerning ‘land swaps’ between the CFNR and the ‘main campus’ to consolidate the area available to the UWC authorities for development of buildings on the UWC main campus. In 1988 it was extracted from the CFNR in a re-survey of the boundaries of the CFNR where the ‘dog’s leg and the northern portion of the CFNR (where the School of Government is now situated and from there southeastwards to the railway line) were ‘traded’ as part of a land swap for a triangular portion of

University of the Western Cape: Botanical Assessment of site for New Life Sciences Building

Figure 2. Aerial image GOOGLE (Image from Google-Earth 2006 ©)

University of the Western Cape: Botanical Assessment of site for New Life Sciences Building

land that has now been incorporated into the CFNR at the southwestern end of the ‘dog’s leg’ portion, however, has been recognized as an important fragment of Cape Flats habitat that augments the CFNR and its conservation purposes. In the period since the inception of the CFNR and subsequent to the resurvey of the boundaries it has been managed as part of the CFNR. Thus the evaluation of the vegetation and flora of the ‘dog’s leg’ is made in the context of the Cape Flats Nature Reserve as a whole for comparative purposes but the focus is on the merits and demerits of the ‘dog’s leg’ itself and how it will be impacted by any proposed development.

3.2 Geology and topography

The study area is almost flat and lies at an elevation of approximately 60 m a.m.s.l. The substrate consists of deep, alkaline to acid sands of Recent and Tertiary origin. The area would have consisted of a series of dunes and depressions but the southern boundary was bulldozed to form a ‘berm’. An underground cable was also laid diagonally across the site from a mid-point on the southern boundary north-westwards and a linear depression was formed. These activities introduced some physical disturbance to the site and changed its topography. The site is therefore slightly higher (by 1-1.5m) in the south and is lower and flattens out to the north and west. A low depression is also found in the narrow portion near the footbridge (Figure >).

3.3 Climate

The Cape Flats is subject to a mediterranean-type climate with hot, dry summers and cool, wet winters. The average rainfall is in excess of 500 mm per annum and mean temperatures are 20.4 °C in mid-summer (January) and 11.8 °C in mid-winter (July). Mists occur mainly in May and strong desiccating bergwinds can occur preceding the arrival of cold fronts in winter. Frosts occur rarely in winter. The study site falls within this climatic regime.

4. Evaluation Method

The ‘dog leg’ site was evaluated by walking around the site on the existing paths to obtain an overall impression of the site. Then the area was traversed on foot during which time the site was ‘searched’ for the species occurring there. A list of species was made and notes were compiled on the vegetation and plant species at the site. This was compared with existing records for the site while in the field. Co-ordinates were taken of random points throughout the site using a GPS and notes made that were linked to these points in order to build up a ‘picture’ of the vegetation (Figure 3). Particular attention was given to the possibility of finding ‘red data’ species. Other site characteristics such as geology, soil, disturbance and faunal activity were also recorded. Photographs were taken to provide a record of the vegetation at the site.

Figure 3. Map of portion of UWC showing proximity of the site to Modderdam Road and the sampling track logged by GPS while on the site, with waypoints denoted as UWC #.

Mapping of the vegetation of the ‘dog’s leg’ was also informed by two colour aerial photographs taken of the CFNR in 1996 and 2001.

5. The Vegetation

5.1 The vegetation in context

The unabated demand for land for urban development has seen the unprecedented growth of housing and industrial developments on the Cape Flats since the early 1980’s. In a survey of conservation priority of the Cape Flats by McDowell (1990) stated,

‘The objective of the survey, as described within this report, has been to promote the protection of that privately and / or publicly owned open space which still supports natural plant cover within the study region. At present, the total area of remnant vegetation enjoying formal conservation status is negligible.

On the other side of the coin, the survey recognizes the dire demand for land to be used to meet the escalating demands of a rapidly burgeoning population for residential, industrial and educational facilities. It is the actual siting of such development which is at issue. The present study has demonstrated that large open areas still exist which have negligible quality as natural ecosystems. Such areas should be earmarked for development – not those sites containing highly valued natural assets.’

Significant further loss of natural habitat has occurred since the time of McDowell’s report and with it many endemic plant species (Maze, Kätzschner & Myrdal 2002). Historically the vegetation on the Cape Flats was mainly Sand Fynbos. The exceptions were areas where limestone or calcareous dunes occurred, where the vegetation was more a thicket and was referred to as Dune Thicket (Low & Rebelo 1996) or Cape Flats Fynbos – Thicket Mosaic (Cowling et al. 1999; Cowling & Heijnis 2001). The national classification of the vegetation of South Africa, recently published as maps, classifies the vegetation as Cape Flats Sand Fynbos (FFd5) (Mucina, Rutherford & Powrie 2005). For practical interpretive reasons, Helme et al. (2005) grouped the vegetation type found on the Cape Flats with other types under the heading of ‘Lowland Fynbos Ecosystems’, incorporating Sand Fynbos and Limestone Fynbos. Estimates as at 1996 were that 81% of the Cape Flats Sand Fynbos had been transformed (Rouget et al. 2004), however, due to substantial urban pressure it is now believed that even more of this vegetation type has been lost with possibly more to follow. It is thus a CRITICALLY ENGANGERED vegetation type (Rouget et al. 2004; Helme et al. 2005). Every fragment of land on the Cape Flats that harbours natural vegetation is thus important and should be seen as vital in the patchwork of conservation areas necessary to ensure the continued survival of the vegetation types and the plant species they contain.

5.2 The vegetation of the Cape Flats Nature Reserve (CFNR).

The vegetation and flora of the CFNR was described by Low (1986) where he identified two veld types, Strandveld, a broad-leaved, sclerophyllous shrubland and alkaline Coastal Fynbos, now known as Sand Fynbos. Details of the vegetation according to Low’s (1986) description are given in Appendix 1. A map of the vegetation as described by Low is given in Figure 4.

Figure 4. Vegetation of the Cape Flats Nature Reserve (from Low 1986) showing the reserve prior to the augmentation of the triangle at the southwestern end. The ‘dog’s leg’ portion is highlighted by enclosure in a red line.

Portions of the two aerial photographs taken of the CFNR in 1996 and 2001 were extracted to show the ‘dog’s leg’ section specifically (Figures 5 & 6). The 1996 photograph (Figure 5) shows the vegetation 19 years after the reserve was proclaimed and 10 years after the vegetation was mapped by Low (1986). The 2001 photograph (Figure 6) shows the vegetation five years after 1996. The Google Earth ® image shown in Figure 7 shows the vegetation presently (2006), five years after 2001. These images provide a useful record of the changes that have occurred in the vegetation at the study site over the past 10 years.

University of the Western Cape: Botanical Assessment of site for New Life Sciences Building

Figure 5. The ‘dog’s leg’ section of the Cape Flats Nature Reserve indicated by the red boundary line. Aerial photograph taken in 1996.

Figure 6. The ‘dog’s leg’ section of the CFNR, red boundary line as in 2001.

Figure 7. Aerial photo of the ‘dog’s leg’ extracted from Google Earth ® showing the vegetation as in 2006.

University of the Western Cape: Botanical Assessment of site for New Life Sciences Building

Low (1986) distinguished four vegetation units in the ‘dog’s leg’ section of the CFNR. Thamnochortus erectus Veld occupied the largest area, to the southeast of the footbridge and along the eastern to mid-central area of the western limb. Ehrharta Grassland was found partly on the southern boundary and extending in a band from the mid-central area to the western boundary. Closed and tall Coastal Fynbos (now called Sand Fynbos) was found along the southern boundary and in the narrow section eastern limb. Imperata cylindrica Grassland was to be found in the extreme northwestern corner.

The 1996 aerial photograph was not easily stratified but the vegetation as described by Low (1986) could be distinguished although the Imperata cylindrica Grassland in the extreme northwest corner had become overgrown with thicket vegetation by that time. The state of the vegetation had not change much by 2001. The plant communities were mature and the thickets dominated by Rhus species were encroaching more into the grassland units.

In 2005 there was a fire that burnt the major part of the eastern limb of the ‘dog’s leg’ section up to the footbridge and a large part of the mid-central are up to the western boundary at Modderdam Road. A portion from more-or-less the middle of the western limb to the northern boundary was not burnt.

The presence of burnt and unburnt areas within the ‘dog’s leg’ section of the reserve provided an opportunity for comparison of the vegetation in a post-fire ‘pioneer’ phase with vegetation in a mature state. The drawback, however, was that the field work was conducted in late October so most of the winter-flowering geophytes had already set seed and were not readily identified.

5.2.1 Description of the vegetation at random positions within the ‘dog’s leg’