environmental impact report: ecological study of the...

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ENVIRONMENTAL IMPACT REPORT:

Ecological study of the proposed Westgate Tarlton Kromdraai

132 kV Power Line and Substation Project for ESKOM in the

Gauteng Province

Prepared by

David Hoare (M.Sc., Pr.Sci.Nat.)

David Hoare Consulting cc

41 Soetdoring Ave Lynnwood Manor,

Pretoria

for

ARCUS GIBB (Pty) Ltd P.O.Box 2700,

Rivonia, 2128

4 September 2008

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REGULATIONS GOVERNING THIS REPORT

This report has been prepared in terms the National Environmental Management Act No. 107 of 1998 (NEMA) and is compliant with Regulation 385 Section 33 - Specialist reports and reports on specialised processes under the Act. Relevant clauses of the above regulation are quoted below and reflect the required information in the “Control sheet for specialist report” given above. Regulation 33. (1): An applicant or the EAP managing an application may appoint a person who is independent to carry out a specialist study or specialised process. Regulation 33. (2): A specialist report or a report on a specialised process prepared in terms of these Regulations must contain: (a) details of (i) the person who prepared the report, and

(ii) the expertise of that person to carry out the specialist study or specialised process;

(b) a declaration that the person is independent in a form as may be specified by the competent authority; (c) an indication of the scope of, and the purpose for which, the report was prepared; (d) a description of the methodology adopted in preparing the report or carrying out the specialised process; (e) a description of any assumptions made and any uncertainties or gaps in knowledge; (f) a description of the findings and potential implications of such findings on the impact of the proposed activity, including identified alternatives, on the environment; (g) recommendations in respect of any mitigation measures that should be considered by the applicant and the competent authority; (h) a description of any consultation process that was undertaken during the course of carrying out the study; (i) a summary and copies of any comments that were received during any consultation process; (j) any other information requested by the competent authority. Appointment of specialist

David Hoare of David Hoare Consulting CC was commissioned by ARCUS GIBB (Pty) Ltd to provide specialist consulting services for the Environmental Impact Assessment and Environmental Management Plan for the proposed Westgate Tarlton Kromdraai 132 kV Powerline and Substation Project in the Gauteng Province. The consulting services comprise an assessment of potential impacts of the proposed project on the flora, fauna and ecology in the study area Details of specialist

David Hoare David Hoare Consulting CC

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Postnet Suite no. 270 Private Bag X844 Silverton 0127 Telephone: (012) 804 2281 Fax: (012) 804 2281 Email: [email protected] Summary of expertise

David Hoare: • Registered professional member of The South African Council for Natural

Scientific Professions (Ecological Science, Botanical Science), registration number 400221/05.

• Founded David Hoare Consulting CC, an independent consultancy, in 2001. • Ecological consultant since 1995. • Conducted, or co-conducted, over 120 specialist ecological surveys as an

ecological consultant. • Published six technical scientific reports, 15 scientific conference presentations,

seven book chapters and eight refereed scientific papers. • Attended 15 national and international congresses & 5 expert workshops,

lectured vegetation science at 2 universities and referee for 2 international journals.

Independence:

David Hoare Consulting CC and its Directors have no connection with ESKOM. David Hoare Consulting CC is not a subsidiary, legally or financially, of the proponent, remuneration for services by the proponent in relation to this proposal is not linked to approval by decision-making authorities responsible for permitting this proposal and the consultancy has no interest in secondary or downstream developments as a result of the authorisation of this project. The percentage work received directly or indirectly from the proponent in the last twelve months is approximately 5% of turnover. Scope and purpose of report

The scope and purpose of the report are reflected in the “Terms of reference” section of this report

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TABLE OF CONTENTS

REGULATIONS GOVERNING THIS REPORT ...............................................................2

Appointment of specialist...................................................................................... 2 Details of specialist.................................................................................................. 2 Summary of expertise ............................................................................................ 3 Independence: .......................................................................................................... 3 Scope and purpose of report ............................................................................... 3

TABLE OF CONTENTS ........................................................................................................4

TERMS OF REFERENCE......................................................................................................6

1. Ecology study terms of reference................................................................. 6 2. General terms of reference............................................................................. 6 3. Exclusions .............................................................................................................. 7

INTRODUCTION ...................................................................................................................8

METHODOLOGY ..................................................................................................................10

Vegetation ................................................................................................................. 10 Threatened flora and fauna................................................................................ 10 Sensitivity Analysis ................................................................................................ 11 Conservation status of vegetation............................................................... 12

Impact assessment ............................................................................................... 13 Assumptions, uncertainties and gaps in knowledge................................. 14 Limitations................................................................................................................. 14

RESULTS: DESCRIPTION OF ECOLOGICAL PATTERNS WITHIN THE

STUDY AREA........................................................................................................................15

Broad vegetation patterns .................................................................................. 15 Carletonville Dolomite Grassland ................................................................. 16 Soweto Highveld Grassland............................................................................ 17

Vegetation and landcover of the study area ............................................... 17 Grassland............................................................................................................... 17 Wetlands ................................................................................................................ 18 Transformed areas............................................................................................. 19

Plant species of special concern ....................................................................... 19 Animal species of special concern ................................................................... 20 Mammals ............................................................................................................... 20 Reptiles................................................................................................................... 20 Amphibians ........................................................................................................... 21

SENSITIVITY ASSESSMENT ..........................................................................................22

Sensitivity of different parts of study area .................................................. 22 Sensitive sites along the proposed alignment ............................................ 24 Sensitivity assessment of different route alternatives ............................ 26

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Corridor 1 .............................................................................................................. 26 Corridor 2 .............................................................................................................. 26 Corridor 3 .............................................................................................................. 27 Corridor 4 .............................................................................................................. 27 Corridor 5 .............................................................................................................. 27 Corridor 6 .............................................................................................................. 28 Corridor 7 .............................................................................................................. 28 Corridor 8 .............................................................................................................. 28 Kromdraai substation site ............................................................................... 29

ASSESSMENT OF IMPACTS............................................................................................30

Potential impacts .................................................................................................... 30 Assessment of impacts ........................................................................................ 32 Destruction or disturbance to sensitive ecosystems leading to reduction in the overall extent of a particular habitat......................... 37 Destruction of vegetation in the footprint of tower structures leading to reduction in the overall extent of a particular habitat ... 37 Fragmentation of sensitive habitats ........................................................... 37 Destruction/permanent loss of individuals of rare, endangered, endemic and/or protected species .............................................................. 37 Disturbance of natural vegetation during construction phase

through trampling, compaction by motor vehicles etc. leading to degradation or destruction of vegetation or habitat or loss of

individuals of rare, endangered, endemic and/or protected species................................................................................................................................... 38 Impairment of the movement and/or migration of animal species resulting in genetic and/or ecological impacts ....................................... 38 Increased soil erosion, increase in silt loads and sedimentation .... 39 Establishment and spread of declared weeds and alien invader plants ...................................................................................................................... 39 Damage to wetland areas ............................................................................... 39 Increased dust during construction leading to potential loss of habitat or displacement of animals ............................................................. 40 Increased noise pollution during construction leading to potential displacement of animals .................................................................................. 40 Increased risk of veld fires leading to damage to sensitive habitats

or loss of individuals of rare, endangered, endemic and/or protected species or loss of vegetation production .............................. 40

Summary of recommendations for mitigation of impacts...................... 40 CONCLUSIONS ...................................................................................................................42

REFERENCES .......................................................................................................................44

APPENDIX 1: Preliminery checklist of plant species recorded. .......................46

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TERMS OF REFERENCE

1. Ecology study terms of reference It was required that the Ecology study provide technical advice on the following information, applicable to the proposed alternative power line corridors and the proposed substation location:

• A brief discussion on the vegetation types in which the study area is situated, using available literature, in order to place the study in context;

• A broad-scale map of the vegetation and landcover of the proposed alignments using available aerial photography. A description of the dominant and characteristic species within the broad-scale plant communities comprising each of these units;

• A list of Red List plant and animal species previously recorded within the quarter degree grids in which the study area is situated, obtained from the relevant authorities and literature reviews;

• Identification of sensitive habitats and plant communities. A map of sensitive areas along the proposed alignments;

• A general site visit to the proposed sites; • Preliminary investigation of the impacts of the proposed powerline and

substation and the provision of recommended mitigation measures; and • Indication of the preferred power line corridor alignment and location of the

substation. 2. General terms of reference General terms of reference also included the following:

• Design and undertake the specialist study in accordance with the specifications provided;

• Describe the baseline conditions that exist in the study area and identify any sensitive areas that would need special consideration;

• Provide an outline of the approach used in the study; • Assessment of all project alternatives including the no-go alternative; • Identify, assess and evaluate the possible impacts of the power line and sub

station during all development phases (construction and operation) of the proposed project;

• Identify and assess any cumulative impacts arising from the proposed project;

• Determine the significance of assessed impacts according to the methodology provided by ARCUS GIBB and provide a residual significance rating of assessed impacts after the implementation of mitigation measures;

• Undertake field surveys, as appropriate to the requirements of the particular specialist study;

• Identify areas where integration of studies with other specialists would ensure a better assessment and coordinate with other specialists in this regard;

• Apply the precautionary principle in the assessment of impacts, in particular where there is major uncertainty, low levels of confidence in predictions and poor data or information;

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• Recommend practicable mitigation measures to minimize or eliminate negative impacts and/or enhance potential project benefits;

• Recommend appropriate auditing, monitoring and review measures; • Compile all information into a stand-alone report according to the format

provided by ARCUS GIBB; and • All specialist studies must take cognizance of and comply with the relevant

guideline documents applicable to that specialist study. 3. Exclusions This study specifically excludes the following:

1. The avifauna impact assessment, which will be undertaken by a separate specialist.

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INTRODUCTION

Eskom appointed ARCUS GIBB (Pty) Ltd to undertake an EIA for the proposed Westgate Tarlton Kromdraai 132 kV power line and substation, including the compilation of a Scoping Report, Environmental Impact Report (EIR) and Environmental Management Plan (EMP). The project comprises of the construction of a 132 kV power line, which is proposed to start at the existing Westgate Substation and continue through either of two proposed alignments to the existing Tarlton Substation. From the Tarlton Substation there are three proposed alignments leading to the location of the proposed Kromdraai Substation. A detailed indication of the routes is given in Figure 1 and consists of the following components:

1. Corridor 1 (shown in red): begins at the existing Westgate Substation, travels westwards to Randfontein Estates, then meanders north-westwards to end at the existing Tarlton substation.

2. Corridor 2 (shown in purple): is an alternative alignment for a portion of corridor 1.

3. Corridor 3 (shown in light blue): is a crossover alternative between corridor 1 and 2.

4. Corridor 4 (shown in orange): is between the existing Tarlton substation to

Figure 1: General view of study area showing alternative alignments.

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the proposed Kromdraai substation that begins by first travelling northwards and then meandering east- to north-eastwards to the site of the proposed Kromdraai substation.

5. Corridor 5 (shown in pink): is an alternative alignment for a portion of corridor 4 slightly further northwards.

6. Corridor 6 (shown in blue): is a linkage between corridor 1 and 4. 7. Corridor 7 (shown in green) is primarily a combination of existing alignments

with an added section through the Krugersdorp Nature Reserve. 8. Corridor 8 (shown in dark blue) use some sections of other alignments, but

includes a section south of Tarlton substation and another section south of the proposed Kromdraai substation to the north of the Krugersdorp Nature Reserve.

A full EIA process for the project was required, including a scoping study, an EIR and EMP. The study was to be on a regional level, with the detailed studies of the tower footprints being undertaken during the detailed EMP phase (after Eskom have surveyed and pegged the approved route). David Hoare Consulting cc was appointed on 26 November 2007 by ARCUS GIBB (Pty) Ltd to provide specialist ecological consulting services for the Environmental Impact Assessment for the proposed Westgate Tarlton Kromdraai 132 kV powerline and substation Project in the Gauteng Province. The consulting services comprise an assessment of the proposed projecton the flora, fauna and ecology in the study area. This report comprises the ecological assessment of the project study area for the EIA study and assesses potential impacts of the proposed alignments of the proposed 132 kV powerline.

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METHODOLOGY

Vegetation

A literature survey was undertaken to locate studies done in the area. From this, broad vegetation patterns and more detailed plant community descriptions were obtained. These descriptions were detailed enough to compile a preliminary plant community map of the study area. This was done by mapping from aerial photographs of the study area using other environmental layers and maps for additional information, e.g. topography, land-types, etc. This preliminary map was ground-truthed during a brief field visit from 20-21 December 2007 and again on 17 July 2008. During the field surveys, additional data was collected in untransformed natural vegetation. This quantitative data was collected in natural vegetation by undertaking vegetation sampling according to the Braun-Blanquet approach (Mueller-Dombois & Ellenberg 1974; Westhoff & van der Maarel 1978). In each sample site the following data was collected:

• species present; • cover estimation of each species according to the Braun-Blanquet scale; • vegetation height; • amount of bare soil and rock cover; • slope, aspect in degrees, latitude and longitude position (from GPS) in

decimal degrees; and • presence of biotic disturbances, e.g. grazing, animal burrows, etc.

Additional checklists of plant species were compiled by traversing the study area on foot and recording species as they were encountered, although garden plants are not listed here. Plant names follow Germishuizen & Meyer (2003). Due to the brief duration of the survey and the lack of seasonal coverage, the species list provided for the area can not be regarded as comprehensive, but is nevertheless likely to include the majority of the dominant and common species present within the plant communities sampled. The published studies combined with the field data collected were sufficient to provide an indication of species composition, diversity and the presence of plant species of special concern within different plant communities. All exotic species categorised as alien invaders or weeds (as listed in amendments to Conservation of Agricultural Resources Act, 1983, Act No. 43 of 1983) were recorded. The general status of the vegetation was derived by updating the National Landcover data layer for the study area (Fairbanks et al. 2000) using available aerial photography. From this it could be determined which areas were transformed and no longer had primary vegetation. Threatened flora and fauna

A list of Red Data flora species which could potentially occur within the study area was compiled on the basis of existing data (from GDACE) for the quarter degree squares 2627 BA. A preliminary list was compiled and used to evaluate which species were likely to occur in the available habitats in the study area.

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No field surveys to determine the composition of the fauna was undertaken. To reliably assess the possible presence/absence of Red Data fauna species an assessment of the presence, status and linkage of available habitat in the study area was undertaken. These attributes were rated for each species using the available literature and personal field experience in studying habitat patterns. The three parameters used to assess the probability of occurrence for each species were as follows:

• Habitat requirements: most Red Data animals have very specific habitat requirements and the presence of these habitat characteristics within the study area were assessed;

• Habitat status: in the event that available habitat is considered suitable for these species, the status or ecological condition was assessed. Often, a high level of degradation of a specific habitat type will negate the potential presence of Red Data species (especially wetland-related habitats where water-quality plays a major role); and

• Habitat linkage: movement between areas used for breeding and feeding purposes forms an essential part of ecological existence of many species. The connectivity of the study area to these surrounding habitats and adequacy of these linkages are assessed for the ecological functioning Red Data species within the study area.

For all threatened organisms (flora and fauna) that occur in the general geographical area of the site, a rating of the likelihood of it occurring on site is given as follows:

• LOW: no suitable habitats occur on site / habitats on site do not match habitat description for species;

• MEDIUM: habitats on site match general habitat description for species (e.g. grassland), but detailed microhabitat requirements (e.g. rocky grassland on shallow soils overlying dolomite) are absent on the site or are unknown from the descriptions given in the literature or from the authorities;

• HIGH: habitats found on site match very strongly the general and microhabitat description for the species (e.g. rocky grassland on shallow soils overlying dolomite);

• DEFINITE: species found on site. Sensitivity Analysis

Sensitivity of habitats and sites within the study area was assessed using a combination of criteria, as follows: Criterion Definition

1 Conservation status of untransformed habitats occurring in the study area.

The extent of each broad vegetation type occurring within the study area that is conserved and/or transformed relative to a targeted amount required for conservation.

2 Presence and number of Red Data Species and other Species of Special Concern.

Presence or potential presence of Red Data Species within habitats.

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3 Within-habitat species richness of flora and the between-habitat (beta) diversity of the site.

Estimated per habitat type in the study area on the basis of existing knowledge/field data.

4 The type or nature of topography of the site, i.e. presence of ridges, koppies, etc.

Steepness and/or nature of topography in the study area.

5 The type and nature of important ecological processes on site, especially hydrological processes, i.e. wetlands, drainage lines etc.

Habitats and/or terrain features that represent ecological processes, such as water-flow, migration routes, etc.

The first two of these criteria are the most commonly used criteria for assessing the conservation value of a site and also constitute the criterion most commonly employed to justify the conservation of a site. Conservation status of vegetation

On the basis of a recently established approach used at national level by SANBI (Driver et al. 2005), vegetation types can be categorised according to their conservation status which is, in turn, assessed according to degree of transformation relative to the expected extent of each vegetation type. The status of a habitat or vegetation type is based on how much of its original area still remains intact relative to various thresholds. The original extent of a vegetation type is as presented in the recent national vegetation map (Mucina, Rutherford & Powrie 2005) and is the extent of the vegetation type in the absence of any historical human impact. On a national scale the thresholds are as depicted in Table 1, as determined by best available scientific approaches (Driver et al. 2005). Table 1: Determining ecosystem status (from Driver et al. 2005). *BT =

biodiversity target (minimum conservation requirement).

80–100 least threatened LT 60–80 Vulnerable VU *BT–60 Endangered EN

Habitat

remaining

(%)

0–*BT critically endangered CR The level at which an ecosystem becomes Critically Endangered differs from one ecosystem to another and varies from 16% to 36% (Driver et al. 2005). The national status is based on 1996 National Landcover data (Fairbanks et al. 2000) and is, therefore, out of date. Additional transformation has taken place since 1996 and satellite data is also not able to distinguish secondary vegetation from untransformed vegetation (Hoare et al. in prep.). For this reason updated transformation information is often required to improve the conservation assessment. Landcover data supplemented with topocadastral data (1:50 000 series from the Surveyor General), aerial photographs, satellite data and field verification can be used to produce improved landcover maps to indicate areas that are considered to be transformed.

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Impact assessment

Potential impacts are evaluated for each route alternative according to an impact rating methodology supplied by ARCUS GIBB (Pty) Ltd. The specified approach requires the following steps:

1. Identify possible impacts. 2. Prediction of impacts using the following criteria:

(a) Nature Whether it is positive, negative or neutral.

(b) Extent of the impact A description of whether the impact will be: (1) local extending only as far as the development site area; or (2) limited to the site and its immediate surroundings; or (3) will have an impact on the region, or (4) will have an impact on a national scale or (5) across international borders. The criterion is scored according to the number in brackets. (c) Magnitude (intensity or severity) The magnitude of the impacts is quantified on a scale from 0-10, where 0 is small and will have no effect on the environment, 2 is minor and will not result in an impact on processes, 4 is low and will cause a slight impact on processes, 6 is moderate and will result in processes continuing but in a modified way, 8 is high (processes are altered to the extent that they temporarily cease), and 10 is very high and results in complete destruction of patterns and permanent cessation of processes.

(d) Duration of the impact The impact is evaluated in terms of whether the lifespan of the impact would be (1) very short term (0-1 years), (2) short term (2-5 years), (3) medium term (5-15 years), (4) long term (> 16 years) or (5) permanent.

(e) Probability of occurrence The probability of the impact actually occurring is a description of the likelihood of the impact actually occurring and is estimated on a scale of 1–5, where 1 is very improbable (probably will not happen), 2 is improbable (some possibility, but low likelihood), 3 is probable (distinct possibility), 4 is highly probable (most likely) and 5 is definite (impact will occur regardless of any prevention measures). (f) Degree to which the impact can be reversed This is an indication of the ability of the environment to return to its pre-impacted state once the cause of the impact has been removed, where 1 is low (impacted functions and processes will return to their pre-impacted state within the short term), 2 is medium (impacted functions and processes will return to their pre-impacted state within the medium to long term) and 3 is high (impacted functions and processes will never return to their pre-impacted state).

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(g) Impact on irreplaceable resources Is an irreplaceable resource impacted upon, yes or no.

(h) Confidence level

3. Identify mitigation measures and predict the residual impact using the same criteria given above

4. Assign a consequence rating using a combination of intensity, extent and

duration

5. Assign a significance rating The significance is defined as a combination of the consequence of the impact occurring and the probability that the impact will occur.

Assumptions, uncertainties and gaps in knowledge

1. Assume databases and literature sources are adequate for determining the possible presence of threatened species. These often depend on good geographical coverage of species observations, which is seldom the case.

2. Assume species threatened status has been correctly determined and that no other species should be on the Red Lists.

Limitations

Descriptions of vegetation are based primarily on literature review in combination with two general site visits (one in early summer, December, and one in winter, August). No detailed assessment of the vegetation of the proposed alignments was undertaken.

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RESULTS: DESCRIPTION OF ECOLOGICAL PATTERNS WITHIN THE STUDY

AREA

The following section provides a description of the environment that may be affected by the activity. This description includes patterns of flora and fauna within the study area. Broad vegetation patterns

There are three general descriptions of the vegetation in the study area. Acocks (1953) published the first comprehensive description of the vegetation of South Africa, which was updated in 1988. This was followed by an attempted improvement (Low & Rebelo 1998) which has become widely used due to the inclusion of conservation evaluations for each vegetation type, but is often less rigorous than Acocks’s original publication. Recently, a more detailed map of the country was produced (Mucina et al., 2005). A companion guide to this map (Mucina & Rutherford 2006), containing up-to-date species information and a comprehensive conservation assessment of all vegetation types, has just been published. The grasslands in the general region that includes the study area have been studied in some detail (Coetzee et al. 1994a, 1994b, 1995; Grobler, 2000, 2006), although it is difficult to ascertain whether the area immediately surrounding the study area has been studied. There is therefore adequate published information that can be used to place the current study area in context (see Mucina et al. 2000), as well as the broad descriptions of Acocks (1953, 1988), Low and Rebelo (1998) and Mucina et al. (2006). The study area falls within Rocky Highveld Grassland (Low & Rebelo 1998), which in turn comprises part of the Grassland Biome (Rutherford & Westfall 1986). Rocky Highveld Grassland covers an area of approximately 24 063 km2 within South Africa, approximately 65% of which has been transformed and 1.4% of which is currently conserved. The transformation within this Vegetation Type is mainly attributable to urbanization and agriculture. The study area is in a part of Gauteng where this vegetation type is relatively fragmented. The most important conservation areas that contain examples of this vegetation type are Suikerbosrand, Rustenburg, Abe Bailey and Boskop Dam Nature Reserves. Acocks (1953) classified this area as Bankenveld. According to Acocks (1988), there are three variations of Bankenveld, a western, a central and an eastern one. The central variation occurs in the Witwatersrand area and represents the study area. It is a wiry and sour grassland on poor, acidic soils. Important species include the grasses Trachypogon spicatus, Tristachya leucothrix, Panicum natalense, Elionurus muticus, Heteropogon contortus, Eragrostis chloromelas, Eragrostis racemosa, Eragrostis capensis, Diheteropogon amplectens, Brachiaria serrata, Schizachyrium

sanguineum, Loudetia simplex, Tristachya rehmannii and many more, as well as a great wealth of forbs, including Helichrysum acutatum, Helichrysum pallidum, Sphenostylis angustifolius, Senecio coronatus, Senecio inornatus, Nidorella

hottentotica, Justicia anagalloides, Cycnium adonense, Pearsonia cajanifolia, Vernonia natalensis and many others. In sandier parts overgrazing will result in an abundance of Stoebe vulgaris.

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The most recent and more detailed description of this vegetation (Mucina, Rutherford & Powrie, 2005; Mucina et al. 2006) indicates that the proposed route falls within two main vegetation types, namely Carletonville Dolomite Grassland and Soweto Highveld Grassland (Figure 2). These are discussed in more detail below. There are also other vegetation types in the surrounding areas, but these will not be affected by the proposed powerline infrastructure. These include Egoli Granite Grassland, Gold Reef Mountain Bushveld, Gauteng Shale Mountain Bushveld and Eastern Temperate Freshwater Wetlands (Figure 2). Carletonville Dolomite Grassland

This is a species-rich mosaic of plant community types occurring on undulating plains dissected by rocky chert ridges. It is a vegetation type that is characterized by the presence of the species, Aristida congesta, Brachiaria serrata, Cynodon dactylon, Digitaria tricholaenoides, Diheteropogon amplectens, Eragrostis chloromelas, Eragrostis racemosa, Heteropogon contortus, Loudetia simplex, Schizachyrium

sanguineum, Setaria sphacelata, Themeda triandra, and a wide variety of herbaceous forbs and other grasses. This vegetation type is considered to be Vulnerable (Driver et al., 2005 and Mucina et al., 2006), and whilst the conservation target is 24%, only a small extent is currently protected and 23% is considered to be transformed, mostly by cultivation (17%), urbanization (4%), forestry (1%) and mining (1%) (Mucina et al. 2006).

Figure 2: Broad vegetation types of the study area (from Mucina, Rutherford & Powrie 2005).

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Soweto Highveld Grassland

This is a short to medium-high, dense, tufted grassland dominated almost entirely by Themeda triandra occurring on moderately undulating landscapes of the Highveld plateau. According to Mucina et al. (2006), this is a grassland that is characterized by the dominance of the species, Themeda triandra, accompanied by a variety of other grasses, such as Elionurus muticus, Eragrostis racemosa, Heteropogon contortus and Tristachya leucothrix. This vegetation type is considered to be Endangered (Driver et al., 2005 and Mucina et al., 2006), and whilst the conservation target is 24%, only a small extent is currently protected and 23% is considered to be transformed with 0.2% conserved of a target of 24% and approximately 47% transformed, mainly by cultivation, urban sprawl, mining and building of road infrastructure (Mucina et al. 2006). Vegetation and landcover of the study area

The study area within which the proposed powerline will be constructed currently consists of a mixture of urban areas, agricultural, stands of alien trees, degraded areas and some remaining fragmented patches of natural vegetation. The vegetation types and landcover classes along the proposed routes, as determined during the field survey, are described in general terms in more detail below and a map of these is given in Figure 3. Grassland

In the area that may be affected by the proposed infrastructure, there are four small areas of grassland and one larger extent of grassland (Figure 3). All of these are affected to a large degree by the surrounding land-use. In the southern parts of the study area mining has impacted heavily on remaining areas of natural vegetation and the grassland tends to be in poor condition and often extensively invaded by exotic trees, primarily Acacia mearnsii. This constitutes the remaining areas of the Endangered Soweto Highveld Grassland occurring primarily on Black Reef quartzite geology. In the broad study area, this is a medium to short grassland dominated by the grasses and forbs Cynodon dactylon, Eragrostis curvula, Sporobolus fimbriatus, Setaria sphacelata, Aristida congesta, Pollichia campestris, Bulbostylis burchellii, Eragrostis chloromelas, Brachiaria serrata, Conyza canadesis, Hyparrhenia hirta and Pentarrhinum insipidum. This species composition is indicative of a high disturbance regime. The larger area of grassland in the northern half of the study area (between Tarlton and Kromdraai and including the area within the Krugersdorp Nature Reserve) falls within Carletonville Dolomite Grassland and is classified as Vulnerable and occurring primarily on Chuniespoort dolomite geology. This area has been cultivated to a large degree, but many of the shallower soils were not ploughed and these, along with some areas of sandier soils, constitute the remaining expanse of grassland. There are portions of these grasslands that are in relatively good condition. In the broad study area this is medium height grassland dominated by the grasses and forbs Schizachyrium sanguineum, Themeda triandra, Brachiaria serrata, Digitaria erianthe, Eragrostis racemosa, Panicum natalense, Sporobolus fimbriatus, Eragrostis

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gummiflua, Heteropogon contortus, Diheteropogon amplectens, Eragrostis curvula, Eragrostis chloromelas and Cynodon dactylon. The remaining patches of grassland are considered to have elevated conservation importance due to the poor rates of conservation of this vegetation type nationally as well as the fact that all the threatened, near-threatened or declining plant species that could occur in the study area are most likely to occur in grasslands or in rocky areas within grasslands. There are also six threatened animal species (Hilltop hopper butterfly, Ketsi blue butterfly, Potchefstroom blue butterfly, White-tailed rat, South African Hedgehog, Striped Harlequin Snake) that could occur within this vegetation type in the type of habitats available in the study area. Untransformed natural grassland is therefore considered to have a HIGH sensitivity and conservation importance within the study area along the proposed route. Wetlands

There are two main wetland areas within the study area, one in the south near the Westgate substation and the other in the north near the proposed Kromdraai substation and southwards from there (Figure 3). The southern wetland constitutes a seasonal marsh wetland associated with an unchannelled drainage line and the northern wetland a permanent marsh wetland associated with the Rietspruit stream, a small tributary of the Bloubankspruit that flows into the Crocodile River. Within the marsh wetlands a number of habitats may be distinguished, based on the vegetation structure (e.g. vegetation physiognomy, life form structure and floristic composition)

Figure 3: Landcover of the study area showing natural and transformed areas.

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of the constituent plant communities. The major factors influencing the distribution of these zones include frequency and duration of inundation and/or elevated soil moisture levels. The lower parts of the slopes tend to be more channelled and contain more permanent wetlands than further up-slope, where temporary wetlands may occur. Within the study area, seasonal to temporary wetlands have been heavily impacted by mining, cultivation and urbanisation and are not in good condition. In some places, especially close to existing infrastructure, they are heavily invaded by alien plant species. It is difficult to assess the floristic value of affected wetlands along the proposed route due to the fact that no comprehensive regional conservation assessment of these systems has been undertaken for the Highveld region in the same way as terrestrial vegetation types. However, wetland vegetation is considered to have elevated conservation importance due to the importance of these habitats in hydrological and ecological processes. There is one animal species (Marsh sylph butterfly) that could occur within this vegetation type in the type of habitats available in the study area. Wetlands are therefore considered to have a HIGH sensitivity and conservation importance where it occurs along the proposed alignment. Transformed areas

There are various types of transformation in the study area, the most significant being mining, cultivation and urbanisation. There are significant areas covered by dense stands of alien trees, primarily Acacia mearnsii and Eucalyptus camaldulensis. There are also disturbed areas adjacent to transformed areas or areas with bare soil. Most of the area crossed by the proposed powerline consists of such transformed or degraded areas. From an ecological perspective, all these areas are considered to be transformed and have LOW conservation value and sensitivity. Species of special concern

Plant species of special concern are listed in Appendix 2, and animal species of special concern are listed in Appendix 3. For an explanation of the International Union for Conservation of Nature (IUCN Ver. 3.1) categories (IUCN, 2001), and Orange List categories (Victor & Keith, 2004), see Appendix 4. Plant species of special concern

Lists of threatened plant species previously recorded in the study area in which the proposed infrastructure is situated were obtained from the South African National Biodiversity Institute and literature sources for the quarter degree grid in which the study area is located. These are listed in Appendix 2, along with the habitats in which they are most likely to be found (see Appendix 2). Two threatened orchid species (Habenaria barbertoniae and Habenaria mossii) have a high probability of occurring within the study area, and one additional threatened species (Melolobium subspicatum) has a medium probability of occurring in the study area. Searches for these species in the study area during fieldwork did not locate any plants, but given the large area surveyed and the nature of the species, it is possible that they could have been overlooked. If any of the species are present, it would be

20

in untransformed areas, and it is possible that construction of pylons or substations could impact on these species by direct destruction or transformation of the habitat in which they occur. This could only be determined upon close inspection of any sites occurring in natural areas that will be affected by the proposed infrastructure. Two species (Hypoxis hemerocallidea and Eucomis autumnalis subsp. clavata) classified as LC (Declining) that have a medium and high probability of occurring in the study area are not of concern, since both are very widespread and destruction of a small part of the total population will not in any way impact on the chance of survival of these species in the future. Two species that are listed as DD and have a medium probability of occurring in the area (Cheilanthes deltoidea subsp nov. and Lotononis adpressa subsp. leptantha) are unlikely to be negatively affected by construction of the power lines, one being in a habitat that is inaccessible to transformation activities, and the other being a taxonomic problem. Animal species of special concern

The objective of this section was to compile a list of animal species that could occur in the study area for which there is conservation concern. These species are listed in Appendix 3. Those species with a geographical distribution that includes the study area are discussed further. Mammals

No red data mammals have been confirmed for the study area (information provided by GDACE). However, Geoffroy’s horseshoe bat (Rhinolophus clivosus), Peak-saddle Horseshoe bat (Rhinolophus blasii), Temminck’s hairy bat (Myotis tricolor), White-tailed rat (Mystromys albicaudatus) and the South African Hedgehog (Atelerix frontalis) occurred here historically (museum records). Other vertebrate species with a distribution and habitat preference that co-incides with the current study area are the Striped Harlequin Snake and Giant Bullfrog. On the basis of habitat preference and geographical distribution, the White-tailed rat and South African Hedgehog have only a MEDIUM chance of occurring at sites along the route, but no signs of any of them were found. The Southern African Hedgehog occurs in a wide variety of terrestrial habitats where there is ample ground cover. It could therefore occur in any untransformed terrestrial habitats in the study area. The White-tailed Rat occurs in Highveld and montane grassland, where it requires sandy soils with good cover. It has been previously recorded in this grid and could therefore occur in grasslands within the study area. Reptiles

There is one Red List reptile species that could occur in the study area, the Striped Harlequin Snake. This species has a MEDIUM chance of occurring in the study area and, on the basis of habitat requirements, could occur in old termitaria or under rocks in grassland. It could therefore occur in the grasslands in the study area.

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Amphibians

There is one Red List amphibian that could occur in the study area, the Giant bullfrog. This species occurs in seasonal, shallow grassy pans in flat open areas, but also utilizes non-permanent vleis and shallow water on the margins of waterholes and dams. It has not previously been recorded in the study area and, on the basis of habitat requirements, has only a MEDIUM chance of occurring in the study area as a whole.

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SENSITIVITY ASSESSMENT

Sensitivity of different parts of study area

The sensitivity assessment is an attempt to identify those parts of the study area that may have high conservation value or that may be sensitive to disturbance. Areas containing untransformed natural vegetation, high diversity or habitat complexity, Red List organisms or systems vital to sustaining ecological functions are considered sensitive. In contrast, any transformed area that has no importance for the functioning of ecosystems is considered to have low sensitivity. Information from various sources, including Gauteng Department of Agriculture, conservation and enviroment’s (GDACE) Conservation Plan (C-Plan) version 2, national assessments and observations made in the field, were used to provide information on the location of sensitive features. According to C-Plan version 2 there are a number of natural features within the study area that may be considered to have conservation value and that may be directly affected by the proposed alignment. This includes the following:

1. primary vegetation (grassland): the study identified two major vegetation types occurring in the study area. These vegetation types have been

Figure 4: Habitat sensitivity / conservation value of different parts of the study area.

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identified at a national level as having different conservation values depending on the amounts conserved and transformed. The Carletonville Dolomite Grassland is considered to be Vulnerable and the Soweto Highveld Grassland as Endangered;

2. non-perennial drainage lines representing a number of ecological processes (groundwater dynamics, hydrological processes, nutrient cycling and wildlife dispersal);

3. areas classified as ridges; and 4. habitat for Red Data plants, mammals, invertebrates or birds.

Some of these areas are classified in C-Plan version 2 as “Important” and others as “Irreplaceable”. For the distribution of these within the study area, refer to Figure 5. In addition to these features identified in C-Plan version 2 there are also a number of additional features that need to be taken into account in order to evaluate sensitivity along the proposed alignment. These include the following:

1. potential occurrence of populations of Red List organisms, including the following that have been evaluated as having a HIGH chance of occurring within habitats along the proposed alignment or within close proximity to it:

a. Habenaria mossii (orchid) b. Habenaria barbetoniae (orchid) c. Hilltop hopper butterfly

Figure 5: GDACE’s C-Plan 2 sites of conservation importance in the study area.

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2. potential occurrence of populations of Red List organisms, including the following that have been evaluated as having a MEDIUM chance of occurring within habitats along the proposed alignment or within close proximity to it:

a. Cheilanthes deltoidea subsp nov. (fern) b. Lotononis adpressa subsp. leptantha (plant) c. Melolobium subspicatum (plant) d. White-tailed rat e. Southern African hedgehog f. Marsh sylph butterfly g. Ketsi blue butterfly h. Potchefstroom blue butterfly i. Striped harlequin snake j. Giant bullfrog

3. occurrence of a number of wetlands. The study area has areas that have been transformed by various factors, including cultivation, mines and urban areas (Figure 3). There are also some degraded areas close to large urban settlements and areas invaded by alien trees. The degraded and transformed areas have been assigned a sensitivity score of “low” since they have little capacity to harbour biodiversity or threatened species and do not contribute to the conservation of vegetation patterns. This does not imply that they have no natural value, but that they have reduced conservation value in terms of preserving patterns of species distribution and species composition. The remaining natural areas have been given a sensitivity score of “high”. The study site is not close to any of the Centres of Plant Endemism (van Wyk & Smith 2001). A map of the sensitivity and conservation value of the different parts of the study area is shown in Figure 4, which shows the distribution of areas in different sensitivity classes (low, medium, high) relative to the proposed infrastructure. It is possible from this map to be able to identify areas where there are possible conflicts between the alignment of the proposed infrastructure and areas of high sensitivity or conservation value. Sensitive sites along the proposed alignment

There were a limited number of sites along the proposed alignment that were considered to be potentially sensitive. These are shown in Figure 6. The sites shown are all those areas that are considered to still contain natural vegetation of sufficient size and in sufficiently good condition to still be ecologically functional and potentially suitable for populations of threatened plant or animal species. The proposed route traverses a largely urban, mining and cultivated environment and this has had a major impact on the natural vegetation in the study area. There were, for example, various places that were covered with secondary grassland or grassland that was degraded to the extent that it is no longer considered to be natural.

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Figure 6: Potentially sensitive sites within the vegetation along the proposed alignments.

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Sensitivity assessment of different route alternatives

A summary of potential sensitivities along each corridor is provided below. The route sections are as shown in Figure 6 and described in the text. A separate small map of each alignment is also given next to each description.

Corridor 1

This route is approximately 19.0 km long. The majority of this alignment is through areas transformed by cultivation, small holdings, alien trees, mining or other activities. There is 2.1 km of grassland in the central portion that is in moderate condition, 0.5 km where it crosses a non-perennial stream (a tributary of the Rietspruit), which is adjacent to a small ridge, and approximately 800 m of moderate condition grassland at the northern end. The central section is classified in C_plan as “Important” due to the existence of primary grassland which is also a historical locality for a Red List invertebrate and a Red List plant species. An additional 2.0 km of grassland occurs on the southern end, but this is adjacent to a gravel road and existing powerline, infested with alien trees and in poor condition, the only

part clear of aliens is under the existing powerline. The extreme northern and extreme southern sections are classified in C-plan as “Irreplaceable” due to the existence of primary grassland and bird habitat. Approximately 24% of the alignment is within untransformed habitat.

Corridor 2

This alignment is approximately 8.0 km long and is an alternative to the southern portion of Corridor 1. The majority of this alignment is in areas transformed or disturbed by a combination of alien trees, a mine dump, cultivation, urban areas and existing roads. There is approximately 4.0 km of undisturbed natural grassland along this alignment. The alignment includes 3.4 kilometres classified in C-Plan as “Irreplaceable” (of which 0.8 km is considered from the current analysis to be highly disturbed) and 1.2 km classified as “Important”. There is, therefore approximately 3.6 km of this alignment that is potentially problematic in terms of the conservation value of the grassland. A comparison between this alignment and the section of Corridor 1

that it replaces indicates that Corridor 1 is favoured over this alignment due to the fact that it contains no “Irreplaceable” habitat(C-Plan).

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Corridor 3

This is a very short section, approximately 0.7 km long, that links a portion of Corridor 2 to Corridor 1. It is in a disturbed area adjacent to an existing mine dump. Half of this is classified as “Important” in C-plan, but fieldwork indicates that this section is highly degraded and therefore of no conservation value. The short alignment therefore contains no conservation issues. However, due to the fact that Corridor 1 is marginally preferred over Corridor 2, this small connector (Corridor 3) could potentially provide a favourable link to avoid the majority of Corridor 2 where there are conservation issues and still allow the southern section of Corridor 2 to be used.

Corridor 4

This route is a northern alternative connecting Tarlton substation to the proposed Kromdraai substation and is approximately 10.5 km long. Some small holdings and associated disturbance occur near the eastern end, but it crosses mostly natural grassland and a single permanent wetland system (near the eastern end). Approximately 3 km of this alignment is through cultivated lands. The alignment includes two 1.2 km sections and one 0.8 km section of grassland (total of 3.3 km) classified in C-Plan as “Irreplaceable”. Approximately 71% of the alignment is within untransformed habitat. Although this alternative contains a number of sensitive sites, it is preferable to its direct comparison, Corridor 5.

Corridor 5

This route is an alternative for approximately a third of Corridor 4 that links Tarlton substation to the proposed Kromdraai substation. It is approximately 5.6 km long. Some small holdings and associated disturbance occur near the eastern end, but it consists mostly of natural grassland and a single permanent wetland system. A significant length of this alignment is adjacent to an existing powerline. The alignment includes a 2.1 km section of grassland classified in C-Plan as “Irreplaceable”. Approximately 80% of the alignment is within untransformed habitat. Corridor 4 is preferable to this alignment.

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Corridor 6

This linking alignment is approximately 3.6 km long. It is entirely within cultivated lands. There is a small transformed non-perennial drainage line at the northern end (within a cultivated land). There are therefore few conservation concerns within this alignment. However, this is an alignment that links portions of Corridor 1 or 7 to Corridor 4. From an ecological perspective, this is preferable to using the western section of Corridor 4, because there are two areas of grassland designated as “Irreplaceable” in C-plan that would be crossed by this section of Corridor 4.

Corridor 7

This is an alignment that makes use of elements of other alignments, including Corridor 4, 5 and 1. It includes a section that passes through the northern part of the Krugersdorp Nature Reserve and along its south-western boundary, which is unique to this alignment. This section through the reserve is designated as “Reserved” in C-plan and will meet with opposition from provincial conservation authorities. The section through the nature reserve is also primarily untransformed natural grassland that is considered to be sensitive and to have elevated conservation value.

Corridor 8

This corridor consists of a number of segments that provide alternatives to the previous alignments. The unique component of this alignment is the section immediately south of the Tarlton substation that eventually ends up in a similar alignment to Corridor 2, where any of the southern alternatives could be combined with this alignment. There are a number of patches of grassland indicated as “Irreplaceable” in C-plan, but in reality, the sections of concern are the same as those for Corridor 2. There are no ecological features of concern between Tarlton and the joining with Corridor 2. The favoured alignment from an ecological perspective would be to use the Corridor 2 link, follow the alignment that is common with Corridor 1 and then follow the remaining section of Corridor 8 to Tarlton. The other unique

component of this alignment is the section south of the proposed Kromdraai

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substation to the northern boundary of the Krugersdorp Nature Reserve, where it meets up with Corridor 7. This crosses an area of untransformed grassland, which is thought to be potentially sensitive although it is not identified in C-plan as being of conservation concern. Kromdraai substation site

This site is primarily a disturbed area with ruins of a previous building surrounded by weedy vegetation. Surrounding this is natural grassland. Along the eastern side of the site is a gravel road across which is small holdings and agricultural activities for a significant distance away from the site. The site is not identified in C-Plan as important for conservation or ecological processes. According to 1:50 000 topocadastral maps, the site was previously cultivated. The site is therefore not considered to be ecologically sensitive.

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ASSESSMENT OF IMPACTS

Potential impacts

Impacts are described and assessed below. Impacts may arise due to various activities or infrastructure, including the following:

1. pylons; 2. temporary construction impacts; 3. access and service roads impacts; and 4. clearing within servitude, e.g. to maintain vegetation below 4 m height.

Potential impacts and issues include the following:

• Destruction or disturbance to sensitive ecosystems: This will lead to localized or more extensive reduction in the overall extent of a particular habitat. Consequences of this may include:

1. increased vulnerability of remaining portions to future disturbance; 2. negative change in conservation status of habitat; 3. general loss of habitat for sensitive species; 4. loss in variation within sensitive habitats due to loss of portions of

it; 5. general reduction in biodiversity; 6. increased fragmentation (depending on location of impact); and 7. disturbance to processes maintaining biodiversity and ecosystem

goods and services. • Destruction of vegetation in the footprint of tower structures: This will lead to

localized reduction in the overall extent of a particular habitat. This may only be an issue if the tower is situated within a sensitive habitat or upon a population of a species of special concern.

• Fragmentation of sensitive habitats: This will arise due to destruction of

habitat in such a way as to divide areas of habitat partially or fully into smaller parts. Consequences of this may include:

1. impaired gene flow within fragmented populations; 2. breakdown of ecological relationships, e.g. pollinator-plant; 3. breakdown of migration routes; and 4. reduced functional use, e.g. grazing.

• Destruction/permanent loss of individuals of Red List species during the

construction and/or operational phase: This may arise if the proposed infrastructure is located where it will impact on such individuals. Consequences of this may include:

1. negative change in conservation status of affected species; 2. fragmentation of populations of affected species; 3. reduction in area of occupancy of affected species;and

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4. loss of genetic variation within affected species. • Disturbance of natural vegetation through trampling, compaction by motor

vehicles etc.: This may occur around construction sites and in order to access infrastructure. Consequences of this may include:

1. destruction of vegetation or habitat; 2. degradation of vegetation or habitat; 3. loss of sensitive habitats; 4. loss or disturbance to individuals of rare, endangered, endemic and/or

protected species; and 5. fragmentation of sensitive habitats.

• Impacts on the movement and migration of animal species: This will occur if

the infrastructure imposes an insurmountable barrier to movement. Consequences of this may include:

1. impaired gene flow within fragmented populations; 2. breakdown of ecological relationships, e.g. pollinator-plant; and 3. breakdown of migration routes.

• Increased soil erosion, increase in silt loads and sedimentation: This will occur

due to soil disturbance, especially along the steeper slopes, increased run-off from compacted areas etc. Consequences of this may include:

1. loss of or disturbance to indigenous vegetation; 2. loss of sensitive habitats; 3. loss or disturbance to individuals of rare, endangered, endemic and/or

protected species; 4. fragmentation of sensitive habitats; and 5. impairment of wetland function

• Establishment and spread of declared weeds and alien invader plants: This

may occur in disturbed areas and/or where propagules of these plants are readily available. Consequences of this may include:

1. loss of indigenous vegetation; 2. change in vegetation structure leading to change in various habitat

characteristics; 3. change in plant species composition; 4. change in soil chemical properties; 5. loss of sensitive habitats; 6. loss or disturbance to individuals of rare, endangered, endemic and/or

protected species; 7. fragmentation of sensitive habitats; 8. change in flammability of vegetation, depending on alien species; 9. hydrological impacts due to increased transpiration; and 10. impairment of wetland function.

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• Damage to wetland areas: This may occur if wetlands are directly affected by the construction of infrastructure. Consequences of this may include:

1. Impairment of wetland function; 2. reduction in water quality, potentially leading to impacts on wetland

flora and fauna; and 3. change in hydrological regime, usually increased runoff.

• Increased dust during construction: This may affect animals and vegetation in

the vicinity. Consequences of this may include:

1. will cause stress in individuals of various animal species, which may result in them moving away or cause changes in behaviour;

2. will cause some territorial animals to be displaced; and 3. will result in deposition of dust on vegetation leading to impaired

photosynthesis and respiration, potentially causing damage to individual plants.

• Increased noise pollution during construction: This may affect animals in the

vicinity. Consequences of this may include:

1. will cause stress in individuals of various animal species, which may result in them moving away or cause changes in behaviour; and

2. will cause some territorial animals to be displaced.

• Increased risk of veld fires: There is a higher risk of veld fires around construction sites due to the use of fires for cooking, warmth, etc. by construction workers. Consequences of this may include:

1. damage to sensitive habitats; 2. damage to populations of sensitive plant species; and 3. loss of vegetation production leading to reduction in available

grazing/browing for wild or domestic animals. Assessment of impacts

The impacts are evaluated in more detail in Tables 2-4 and specific recommendations for mitigation of these impacts are given below.

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Table 2: Impacts assessed by combining the consequences (magnitude, duration, extent) with the probability of

occurrence before mitigation

Impact Nature Intensity Extent Duration Probability Non-

reversibility

Impact on

irreplaceable

resource?

Confidence

Destruction or disturbance to sensitive

ecosystems leading to reduction in the

overall extent of a particular habitat

Negative Low Local Long-term Definite High Yes High

Destruction of vegetation in the

footprint of tower structures leading to

reduction in the overall extent of a

particular habitat

Negative Low Local Long-term Definite High Yes High

Fragmentation of sensitive habitats Negative Low Local Long-term Probable High Yes High

Destruction/permanent loss of

individuals of Red List species

Negative High National Long-term Probable High Yes High

Disturbance of natural vegetation

through trampling, compaction by

motor vehicles etc. leading to

degradation or destruction of vegetation

or habitat or loss of individuals of rare,

endangered, endemic and/or protected

species

Negative Medium Local Long-term Probable Medium Yes Medium

Impairment of the movement and/or

migration of animal species resulting in

genetic and/or ecological impacts (Red

List species)

Negative High Regional Long-term Probable High No Medium

Increased soil erosion, increase in silt

loads and sedimentation

Negative Medium Local Medium-

term

Probable Medium No Medium

Establishment and spread of declared

weeds and alien invader plants

Negative High Local Long-term Highly

probable

Medium Yes High

Damage to wetland areas Negative High Regional Long-term Improbable Medium Yes Medium

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Increased dust during construction

leading to potential damage of habitat

or displacement of animals

Negative Low Local Short-

term

Probable Low Yes Medium

Increased noise pollution during

construction leading to potential

displacement of individuals


term

Highly

probable

Low No Medium

Increased risk of veld fires leading to

damage to habitats or loss of

individuals of species of concern or loss

of vegetation production


term

Highly

probable

Low Yes High

Table 3: Impacts assessed by combining the consequences (magnitude, duration, extent) with the probability of

occurrence after mitigation

Impact Nature Intensity Extent Duration Probability

Non-

reversibility

Impact on

irreplaceable

resource? Confidence

Destruction or disturbance to sensitive

ecosystems leading to reduction in the


Negative Low Local Long-term Highly

probable

High Yes High

Destruction of vegetation in the

footprint of tower structures leading to

reduction in the overall extent of a

particular habitat

Negative Low Local Long-term Highly

probable

High Yes High

Fragmentation of sensitive habitats Negative Low Local Long-term Improbable High Yes High

Destruction/permanent loss of

individuals of Red List species

Negative High National Long-term Improbable High Yes High

Disturbance of natural vegetation

through trampling, compaction by

motor vehicles etc. leading to

degradation or destruction of vegetation

or habitat or loss of individuals of rare,

endangered, endemic and/or protected

Negative Low Local Long-term Improbable Medium Yes Medium

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species

Impairment of the movement and/or

migration of animal species resulting in

genetic and/or ecological impacts

Negative Low Local Long-term Improbable High No Medium

Increased soil erosion, increase in silt

loads and sedimentation

Negative Low Local Medium-

term

Improbable Medium No Medium

Establishment and spread of declared

weeds and alien invader plants

Negative Low Local Long-term Improbable Medium Yes High

Damage to wetland areas Negative Low Regional Long-term Improbable Medium Yes Medium

Increased dust during construction

leading to potential damage of habitat

or displacement of animals


term

Probable Low Yes Medium

Increased noise pollution during

construction leading to potential



term

Highly

probable

Low No Medium

Increased risk of veld fires leading to

damage to habitats or loss of

individuals of species of concern or loss

of vegetation production

Negative Medium Local Short-

term

Probable Low Yes High

Table 4: Determination of the consequence and significance of impacts

Impact Probability Consequence Significance Confidence

Without mitigation Definite Low Low High Destruction or disturbance to sensitive ecosystems leading to reduction in

the overall extent of a particular habitat With mitigation Highly

probable

Low Low High

Without mitigation Definite Low Low High Destruction of vegetation in the footprint of tower structures leading to

reduction in the overall extent of a particular habitat With mitigation Highly

probable

Low Low High

Without mitigation Probable Low Low High Fragmentation of sensitive habitats

With mitigation Improbable Low Low High

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Without mitigation Probable High High High Destruction/permanent loss of individuals of Red List species

With mitigation Improbable High High High

Without mitigation Probable Medium Medium Medium Disturbance of natural vegetation through trampling, compaction by

motor vehicles etc. leading to degradation or destruction of vegetation or

habitat or loss of individuals of rare, endangered, endemic and/or

protected species

With mitigation Improbable Low Low Medium

Without mitigation Probable High High Medium Impairment of the movement and/or migration of animal species resulting

in genetic and/or ecological impacts


Without mitigation Probable Medium Medium Medium Increased soil erosion, increase in silt loads and sedimentation


Without mitigation Highly

probable

High High High Establishment and spread of declared weeds and alien invader plants

With mitigation Improbable Low Low High

Without mitigation Improbable High High Medium Damage to wetland areas

With mitigation Improbable Medium Low Medium

Without mitigation Probable Low Low Medium Increased dust during construction leading to potential damage of habitat

or displacement of animals With mitigation Probable Low Low Medium

Without mitigation Highly

probable

Low Low Medium Increased noise pollution during construction leading to potential


With mitigation Highly

probable

Low Low Medium

Without mitigation Probable Low Low High Increased risk of veld fires leading to damage to habitats or loss of

individuals of species of concern or loss of vegetation production With mitigation Probable Low Low High

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Destruction or disturbance to sensitive ecosystems leading to reduction in the


The potential magnitude of this impact is low due to the fact that grassland vegetation is not usually cleared below the power lines. It will have an impact at the scale of the proposed infrastructure (pylons and access roads), which is relatively local in extent. The duration of the impact will be permanent and the probability of occurrence is definite, unless the powerline is routed away from sensitive habitats. Mitigation measures:

1. During design stage, ensure powerline is routed outside of sensitive habitats. 2. If sensitive habitats cannot be avoided, then during construction, ensure construction

impacts are contained as much as possible to as small an area as possible. Destruction of vegetation in the footprint of tower structures leading to reduction in

the overall extent of a particular habitat

The potential magnitude of this impact is minor due to the small size of the pylons relative to the overall extent of the natural vegetation. It will have an impact at the scale of the proposed infrastructure, which is very local. The duration of the impact will be permanent and the probability of occurrence is definite. Mitigation measures:


impacts are contained as much as possible to as small an area as possible. Fragmentation of sensitive habitats

Fragmentation may occur if vegetation is completely cleared below the powerline, which does not appear to be the case in the study area where grasslands occur. It is therefore assumed that no clearing will take place and that localised fragmentation may only occur where access roads are required to be constructed. The potential magnitude of this impact is therefore low. This is not too contentious if the impact is located on the edge of the natural area of vegetation, but could be more severe if it cuts a contiguous block of vegetation into pieces. It will have an impact at the scale of the proposed infrastructure, which is relatively regional in extent, although fragmentation is only likely to occur in localised areas. It is therefore scored as being local. The duration of the impact will be permanent and the probability of occurrence is probable. Mitigation measures:


impacts are contained as much as possible to as small an area as possible. 3. Keep construction of access roads to a minimum.

Destruction/permanent loss of individuals of rare, endangered, endemic and/or

protected species

If populations or individuals of Red List species are directly affected by the proposed infrastructure, then the potential magnitude of this impact depends on the overall distribution and abundance of the species concerned. At worst a Critically Endangered or Endangered species may be affected, in which case the impact would be high in magnitude, possibly having a severe impact on the survival probability of the species. If a Critically Endangered or Endangered species is affected then the scale of the impact could be global. The duration of the impact will be permanent and the probability of occurrence is highly probable (depending on where the powerline is routed). Mitigation measures:

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1. During design stage, ensure powerline is routed outside of sensitive habitats or areas where populations of threatened species occur. Assess the footprint of the infrastructure where it occurs in untransformed natural habitat in order to determine whether any populations of sedentary threatened organisms will be affected by the infrastructure. Thereafter, plan to place powerline route and individual pylons and other infrastructure away from these sites. It will be necessary for specialists in different groups of organisms to undertake detailed filed assessments of the untransformed natural habitats where there is a high possibility of Red List organisms occurring. According to the Impact Assessment methodology, the significance remains high even if the probability is reduced to low. The mitigation measures reduce the likelihood of the impact occurring but do not reduce the significance of the impact if they do occur.

Disturbance of natural vegetation during construction phase through trampling,

compaction by motor vehicles etc. leading to degradation or destruction of

vegetation or habitat or loss of individuals of rare, endangered, endemic and/or

protected species

The potential magnitude of this impact is moderate. It will have an impact at the scale of the proposed infrastructure, although this is relatively regional in extent and is therefore scored as regional. The duration of the impact will be long-term, since the vegetation may recover, and the probability of occurrence is probable, unless sensitive habitats are avoided. Mitigation measures:

1. During design stage, ensure powerline is routed outside of sensitive habitats, where possible.

2. If sensitive habitats cannot be avoided, then during construction, ensure construction impacts are contained as much as possible to as small an area as possible. Avoid any sensitive habitats with construction vehicles and equipment during construction and limiting undue trampling, where possible.

3. Keep construction of access roads to a minimum. Impairment of the movement and/or migration of animal species resulting in genetic

and/or ecological impacts

Clearing under the powerline or other infrastructure may cause barriers to movement of animals. This is usually only a problem where the height of the vegetation is physically managed, which is not usually done in grasslands. The potential magnitude of this impact is therefore potentially small since it is unlikely to result in impairment of processes. However, if it affects a population of a sensitive species, the magnitude could be more serious and is scored as moderate. It will have an impact in remaining natural vegetation at the scale of the proposed infrastructure, which would be local in extent, but could affect regional population structure and is therefore scored as regional. The duration of the impact will be permanent and the probability of occurrence is probable, unless the powerline is routed away from sensitive animal populations. Mitigation requires routing the powerline away from known populations of sensitive animal species, in which case the significance can be reduced from a MEDIUM to a LOW negative impact. Mitigation measures:

1. During design stage, ensure powerline is routed outside of sensitive habitats, where possible.

2. During design stage, ensure powerline is routed outside of sensitive habitats or areas where populations of threatened animal species occur. Assess the footprint of the infrastructure where it occurs in untransformed natural habitat in order to determine whether any populations of sedentary threatened animals will be affected by the infrastructure. Thereafter, plan to place powerline route and individual pylons and other infrastructure away from these sites. It will be necessary for specialists from potentially affected groups of animals to undertake detailed filed assessments of the

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untransformed natural habitats where there is a high possibility of Red List animals occurring.

3. Keep construction of access roads to a minimum. Increased soil erosion, increase in silt loads and sedimentation

Where there are erodable soils, it is possible that construction of infrastructure may result in local exposure of the soil surface or increase in runoff off impermeable surfaces. The most severe likely impact would be on wetland systems, where siltation may occur. The potential magnitude of this impact is moderate. It will have an impact at the scale of the proposed infrastructure and possibly downstream, if a drainage area is affected. This infrastructure is relatively regional in extent and potential impacts may extend beyond the study area (in the case of impacts on wetlands). The impact is therefore scored as regional. The duration of the impact will probably be medium-term and the probability of occurrence is probable. Mitigation requires strict stormwater management, and, in which case the significance can be reduced from a MEDIUM to a LOW negative impact. Mitigation measures:

1. A stormwater management plan is required to manage potential runoff problems during construction and operation.

2. Following construction, rehabilitation of disturbed areas is required. 3. Avoid of areas with sensitive soils, steep slopes, etc.

Establishment and spread of declared weeds and alien invader plants

On the basis of existing alien invasions in the study area, the potential magnitude of this impact is considered to be high. It will have an impact at the scale of the proposed infrastructure, although this is relatively regional in extent and is therefore scored as regional. The duration of the impact will be long-term and the probability of occurrence is highly probable, unless effective measures are put in place to reduce the possibility of alien invasions. Mitigation measures:


impacts are contained as much as possible to as small an area as possible. 3. Following construction, rehabilitation of disturbed areas is required. 4. Avoid translocating stockpiles of topsoil from one place to another in order to avoid

translocating soil seed banks of alien species. 5. Keep construction of access roads to a minimum. 6. During operation, the clearing of alien plants within the powerline and infrastructure

servitude is required to control alien invasions. This is mandatory, according to current legislation.

Damage to wetland areas

The potential magnitude of this impact is moderate to high due to the fact that physical alteration to wetlands can have a severe impact on the functioning of those wetlands. It will have an impact at a localised scale, but could result in downstream impacts further away and is therefore scored as regional. There may also be secondary impacts beyond the boundaries of the study area, e.g. reduction in water quality downstream of the development. The duration of the impact will be long-term and the probability of occurrence is improbable since it is unlikely that pylons would be located within major wetlands occurring in the study area. If the powerline pylons and associated infrastructure is kept away from sensitive wetland habitats then the potential impact can be avoided. Mitigation requires keeping the powerline infrastructure outside of sensitive wetland habitats, in which case the significance can be reduced from a HIGH to a LOW negative impact. Mitigation measures:

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1. During design stage, ensure powerline is routed outside of sensitive wetland habitats or drainage areas.

2. A stormwater management plan is required to manage potential runoff problems during construction and operation.

3. Following construction, rehabilitation of disturbed areas is required. 4. Avoid of areas with sensitive soils, steep slopes, etc.

Increased dust during construction leading to potential loss of habitat or

displacement of animals

The potential magnitude of this impact is low to moderate. It will have an impact at the scale of the proposed infrastructure. It is unlikely to be a uniform impact across the entire powerline and more likely to be a localised issue. The impact is therefore scored as local. The duration of the impact will be short-term, primarily for the construction phase and the probability of occurrence is probable. Mitigation measures:

1. During construction, control potential dust problems at construction sites by regular spraying of water onto the ground.

Increased noise pollution during construction leading to potential displacement of

animals

The potential magnitude of this impact is low to moderate. It will have an impact at the scale of the proposed infrastructure. It is unlikely to be a uniform impact across the entire powerline and more likely to be a localised issue where construction is occurring. The impact is therefore scored as local. The duration of the impact will be short-term, primarily for the construction phase and the probability of occurrence is highly probable, depending on the method of construction. Mitigation measures:

1. No mitigation measures are proposed. Increased risk of veld fires leading to damage to sensitive habitats or loss of

individuals of rare, endangered, endemic and/or protected species or loss of

vegetation production

The potential magnitude of this impact is low due to the fact that vegetation already experiences seasonal burning. It is unlikely to be a uniform impact across the entire powerline and more likely to be a localised issue where construction is occurring. The impact is therefore scored as local. The duration of the impact will be short-term, primarily for the construction phase and the probability of occurrence is highly probable. Mitigation requires, in which case the significance can be reduced from a LOW to a LOW(er) negative impact. Mitigation measures:

1. During construction, management of fires emanating from construction camps is required and education of labourers concerning management of fires.

2. During operation, a burning programme should be compiled to reduce fuel loads under powerlines without implementing a fire frequency that is too high for the affected vegetation.

Summary of recommendations for mitigation of impacts

1. Undertake surveys to locate potentially occurring populations of Red List species. Such

populations should be avoided. Recommendations for such surveys are provided in the section below.

2. During and after construction of the infrastructure, ensure effective storm water management around permanent infrastructure, rehabilitate disturbed areas, protect

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topsoil and avoid sensitive soils on steep slopes. This will reduce the possibility of soil erosion.

3. Avoid translocating topsoil stockpiles from one place to another or importing topsoil from other sources that may contain alien plant propagules.

4. Alien plants must be controlled along the powerline and service road servitude as well as within any areas controlled by ESKOM. This should take place during and after construction and may require long-term follow-up.

5. Control dust on construction sites and access roads using water-sprayers. 6. During construction, sensitive habitats must be avoided by construction vehicles and

equipment, wherever possible, in order to reduce potential impacts. Only necessary damage must be caused and, for example, unnecessary driving around in the veld must not take place.

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CONCLUSIONS

There are parts of the study area that are classified as having High sensitivity due to the following factors:

1. the vegetation has a high conservation value due to low rates of conservation and high rates of transformation,

2. there is a possibility of encountering Red List species (plants and animals), 3. there are important ecological processes operating in some localised areas (ridges and

wetlands). There are also areas classified as having High sensitivity where these factors do not operate as strongly, but where the vegetation is still in a natural state. A summary of the spatial distribution of areas in different sensitivity classes is given in Figure 3. The proposed alignments and alignment alternatives cross different proportions of habitats in different sensitivity classes. Some of the proposed alignments may have impacts on sensitive habitats, whereas other alignments are less likely to do so. For example, Corridor 5 and parts of Corridor 4 cross a much greater distance of habitat classified as having High sensitivity than other alignments. A number of potential impacts were identified and assessed. A single impact was assessed as having potentially high residual significance, namely “Destruction/permanent loss of individuals or populations of Red List species”. Mitigation in this case is possible by undertaking surveys of sensitive sites to identify whether any Red List organisms occur there and then avoiding these areas in aligning the powerline. It would be required to study the footprint of the proposed infrastructure in detail to assess the potential for any of these species to occur there. If these species do not occur within this footprint then the impact will not be significant. All other potential impacts can be controlled by application of suitable mitigation measures. Ideally, all areas of High sensitivity should be avoided. On the basis of habitat transformation, the preferred combination of alignments is to use Corridor 1 (Corridor 2 and 3 are equally suitable as alternatives), Corridor 6 and then the remaining section of Corridor 4 to reach the new substation site. However, the comparative sensitivity of the remainder of Corridor 4 and the entire Corridor 5 is similar. Detailed field surveys to clarify the potential presence of Red List organisms is necessary to make a final assessment of the relative sensitivity of these route alternatives. It is recommended that all remaining natural grassland habitat within the alternative alignments (for those alignments that are considered feasible) be carefully searched for populations of Red List species. This could include a walkdown of the final alignment to check and optimise tower positions. On the basis of historical distribution and collection records, information from C-Plan and the assessment of the likelihood of Red List species occurring in the study area, this would require the following specialist studies:

1. Red List plant survey undertaken sometime from February to March to ensure that the flowering time of the potentially occurring plant species is covered. This includes two orchid species of concern that could occur in grassland on dolemite.

2. Invertebrate study in remaining natural habitats by an invertebrate specialist. The survey must take place during the flying season for flying invertebrates and during peak activity periods for non-flying invertebrates i.e. in the adult stage of development of the species. In most cases, the flying season and peak activity period is during the spring/summer months, usually after the first spring rains.

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3. Small mammal study in remaining natural habitats by a small mammal expert. Undertaking such surveys will increase the confidence in the assessment of potential impacts on affected Red List species and identify sites that have ecological features that would limit construction opportunities.

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REFERENCES

ACOCKS, J.P.H. 1988. Veld types of South Africa (3rd edn.). Mem. Bot. Surv. S. Afr. No 28.

Government printer, Pretoria. BARNES, K.N. (ed.) (2000) The Eskom Red Data Book of Birds of South Africa, Lesotho and

Swaziland. Birdlife South Africa, Johannesburg. BRANCH, W.R. (1988) South African Red Data Book—Reptiles and Amphibians. South African

National Scientific Programmes Report No. 151. COETZEE, J.P., BREDENKAMP, G.J. & VAN ROOYEN, N. 1994. Phytosociology of the wetlands of

the Ba and Ib land types in the Pretoria-Witbank-Heidelberg area of the Transvaal, South Africa. South African Journal of Botany 61: 123–133.

COETZEE, J.P., BREDENKAMP, G.J. & VAN ROOYEN, N. 1995. The phytosociology of the grasslands of the Ba and Ib land types in the Pretoria-Witbank-Heidelberg area. South African Journal of Botany 61: 123–133.

COETZEE, J.P., BREDENKAMP, G.J., VAN ROOYEN, N. & THERON, G.K.1994. An overview of the physical environment and vegetation units of the Ba and Ib land types in the Pretoria-Witbank-Heidelberg area. South African Journal of Botany 60: 49–61.

DENT, M.C., LYNCH, S.D. & SCHULZE, R.E. (1989). Mapping mean annual and other rainfall statistics in southern Africa. Department of Agricultural Engineering, University of Natal. ACRU Report No. 27.

FAIRBANKS, D.H.K., THOMPSON, M.W., VINK, D.E., NEWBY, T.S., VAN DEN BERG, H.M. & EVERARD, D.A. (2000). The South African land-cover characteristics database: a synopsis of the landscape. S. Afr. J. Sci. 96: 69–82.

FRIEDMANN, Y. & DALY, B. (eds.) 2004. The Red Data Book of the Mammals of South Africa: A Conservation Assessment: CBSG Southern Africa, Conservation Breeding Specialist Group (SSC/IUCN), Endangered Wildlife Trust, South Africa.

GERMISHUIZEN, g. & MEYER, N.L. (eds) 2003. Plants of southern Africa: an annotated checklist. Strelitzia 14. National Botanical Institute, Pretoria.

GERMISHUIZEN, G., MEYER, N.L., STEENKAMP, Y and KEITH, M. (eds.) (2006). A checklist of South African plants. Southern African Botanical Diversity Network Report No. 41, SABONET, Pretoria.

GROBLER, C.H., BREDENKAMP, G.J. and BROWN, L.R. 2006. Primary grassland communities of urban open spaces in Gauteng, South Africa. South African Journal of Botany. 72: 367–377.

GROOMBRIDGE, B. (ed.) 1994. 1994 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland.

HENNING, S.F. & HENNING, G.A. 1989. South African Red Data Book - Butterflies. South African National Scientific Programmes No. 158, Foundation for Research Development, CSIR, Pretoria.

HILTON-TAYLOR, C (1996) Red Data list of Southern African plants. Strelitzia 4 IUCN (2001). IUCN Red Data List categories and criteria: Version 3.1. IUCN Species Survival

Commission: Gland, Switzerland. LAND TYPE SURVEY STAFF. (1985). Land types of the maps 2628 East Rand, 2630 Mbabane.

Mem. Agric. Nat. Resources S.Afr. 4: 1–261. LOW, A.B. & REBELO, A.G. (1998) Vegetation of South Africa, Lesotho and Swaziland.

Department of Environmental Affairs and Tourism, Pretoria. MILLS, G. & HES, L. 1997. The complete book of southern African mammals. Struik Publishers,

Cape Town. MINTER, L.R., BURGER, M., HARRISON, J.A., BRAACK, H.H., BISHOP, P.J. and KLOEPFER, D.

(eds.) 2004. Atlas and Red Data Bookof the Frogs of South Africa, Lesotho and Swaziland. SI/MAB Series #9. Smithsonian Institution, Washington, DC.

MUCINA, L, BREDENKAMP, G.J., HOARE, D.B & MCDONALD, D.J. 2000. A National Vegetation Database for South Africa South African Journal of Science 96: 1–2.

45

MUCINA, L. AND RUTHERFORD, M.C. (editors) 2006. Vegetation map of South Africa, Lesotho and Swaziland: an illustrated guide. Strelitzia 19, South African National Biodiversity Institute, Pretoria.

MUCINA, L., HOARE, D.B., LÖTTER, M.C., DU PREEZ, P.J., RUTHERFORD, M.C., SCOTT-SHAW, C.R., BREDENKAMP, G.J., POWRIE, L.W., SCOTT, L., CAMP, K.G.T., CILLIERS, S.S., BEZUIDENHOUT, H., MOSTERT, T.H., SIEBERT, S.J., WINTER, P.J.D., BURROWS, J.E., DOBSON, L., WARD, R.A., STALMANS, M., OLIVER, E.G.H., SIEBERT, F., SCHMIDT, E., KOBISI, K., KOSE, L. 2006. Grassland Biome. In: Mucina, L. & Rutherford, M.C. (eds.) Vegetation map of South Africa, Lesotho and Swaziland: an illustrated guide. Strelitzia 19. South African National Biodiversity Institute, Pretoria.

MUCINA, L., RUTHERFORD, M.C. AND POWRIE, I.W. (editors) 2005. Vegetation map of South Africa, Lesotho and Swaziland, 1:1 000 000 SCALE SHEET MAPS. South African National Biodiversity Institute, Pretoria.

MUELLER-DOMBOIS, D. AND ELLENBERG, H. 1974. Aims and methods of vegetation ecology. Wiley, New York.

PASSMORE, N.I. & CARRUTHERS, V.C. (1995) South African Frogs; a complete guide. Southern Book Publishers and Witwatersrand University Press. Johannesburg.

PFAB, M.F. & VICTOR, J.E. (2002) Threatened plants of Gauteng, South Africa. South African Journal of Botany. 68: 370–375.

RUTHERFORD, M.C. & WESTFALL, R.H. (1994). Biomes of southern Africa: an objective categorization. Memoirs of the Botanical Survey of South Africa No. 63.

SACS (South African Committee for Stratigraphy) (1980). Stratigraphy of South Africa Part 1. (comp. Kent, L.E.) Lithostratigraphy of South Africa, South West Africa/Namibia and the Republics of Bophuthatswana, Transkei and Venda. Handbook of the Geological Survey of South Africa 8. Government Printer, Pretoria.

VAN WYK, A.E. & SMITH, G.F. 2001. Regions of floristic endemism in southern Africa. Umdaus press, Hatfield.

WESTHOFF, V. AND VAN DER MAAREL, E. 1978. The Braun-Blanquet approach. In: Whittaker, R.H. (ed.) Classification of plant communities. W. Junk, The Hague.

WHITE, F. 1983. The vegetation of Africa: a descriptive memoir to accompany the UNESCO/AETFAT/UNISO vegetation map of Africa. Natural Resources Research 20. Unesco, Paris.

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APPENDIX 1: Preliminery checklist of plant species recorded.

Species marked with an asterisk are naturalized exotics. Species taxonomy is according to Germishuizen and Meyer (2001). Trees and shrubs

*Acacia mearnsii (Declared invader category 2) *Eucalyptus camaldulensis (Declared invader category 2) *Melia azedarach (Declared invader category 3) Rhus pyroides

Grasses and sedges

Alloteropsis semialata

Aristida congesta ssp. congesta

Aristida diffusa

Brachiaria serrata

Bulbostylis burchellii

Cynodon dactylon

Cyperus margariticeus

Digitaria eriantha

Digitaria monodactyla

Diheteropogon amplectens

Elionurus muticus

Eragrostis chloromelas

Eragrostis curvula

Eragrostis gummiflua

Eragrostis racemosa

Eragrostis superba

Heteropogon contortus

Hyparrhenia hirta

Loudetia simplex

Melinis repens

Melinis nerviglumis

Panicum natalense

Schizachyrium sanguineum

Setaria sphacelata

Themeda triandra

Tristachya rehmannii

Herbaceous plants

Albuca species

Asclepias species

Blepharis integrifolia

Chaetacanthus costatus

Chamaecrista comosa

Chascanum hederaceum

Cyanotis speciosa

Felicia muricata

Helichrysum callicomum

Helichrysum kraussii

Hermannia depressa

Hypoxis iridifolia

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Indigofera comosa

Indigofera melanadenia

Ipomoea ommaneyi

Justicia anagalloides

Kohautia amatymbica

Ledebouria ovatifolia

Ledebouria revoluta

Lotononis eriantha

Nidorella hottentotica

Oldenlandia herbacea

Oxalis obliquifolia

Pellaea calomelanos

Pollichia campestris

Pseudognaphalium oligandrum

Raphionacme hirsuta

*Richardia brasiliensis

Scabiosa columbaria

Senecio venosus

Solanum sisymbrifolium

Sporobolus fimbriatus

Stoebe vulgaris

*Tagetes minuta

Tephrosia rhodesica

Tolpis capensis

Ursinia nana

Walafrida densiflora

environmental impact report: ecological study of the...

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