helios-juno powerline: vegetation assessment · helios-juno powerline: vegetation assessment iii...

92
The Proposed Helios-Juno Powerline Project, 765kV Transmission Powerline and substations upgrade, Northern Cape and Western Cape Provinces Vegetation Assessment Date: October 2013 Updated July 2015 Report drafted for: Mokgope Consulting Tel: 011 440 1817 Fax: 086 6079481 49 3 rd Avenue, Highlands North Email: [email protected] or [email protected] Report drafted by: Copyright Copyright in all text and other matter is the exclusive property of the author. It is a criminal offence to reproduce and/or use, without written consent, any matter, technical procedure and/or technique contained in this document. Criminal and civil proceedings will be taken as a matter of strict routine against any person and/or institution infringing the copyright of the author and/or proprietors. This document may not be modified other tan by the author and when incorporated into overarching studies, it should be included in its entirety as an appendix to the main report.

Upload: others

Post on 02-Jun-2020

6 views

Category:

Documents


0 download

TRANSCRIPT

  • The Proposed Helios-Juno Powerline Project, 765kV

    Transmission Powerline and substations upgrade,

    Northern Cape and Western Cape Provinces

    Vegetation Assessment

    Date: October 2013

    Updated July 2015

    Report drafted for:

    Mokgope Consulting

    Tel: 011 440 1817

    Fax: 086 6079481

    49 3rd Avenue, Highlands North

    Email: [email protected] or

    [email protected]

    Report drafted by:

    Copyright

    Copyright in all text and other matter is the exclusive property of the author. It is a criminal offence to reproduce and/or use, without

    written consent, any matter, technical procedure and/or technique contained in this document. Criminal and civil proceedings will be

    taken as a matter of strict routine against any person and/or institution infringing the copyright of the author and/or proprietors. This

    document may not be modified other tan by the author and when incorporated into overarching studies, it should be included in its

    entirety as an appendix to the main report.

    mailto:[email protected]:[email protected]

  • Indemnity

    This report is based on survey and assessment techniques which are limited by time and budgetary constraints relevant

    to the type and level of investigation undertaken. The findings, results, observations, conclusions and recommendations

    given in this report are based on the author’s best scientific and professional knowledge as well as available information

    at the time of study. Therefore, the author reserves the right to modify aspects of the report including the

    recommendations if and when new information may become available from ongoing research or further work in this

    field, or pertaining to this investigation.

    Although the author exercises due care and diligence in rendering services and preparing documents, she accepts no

    liability, and the client, by receiving this document, indemnifies the author against all actions, claims, demands, losses,

    liabilities, costs, damages and expenses arising from or in connection with services rendered, directly or indirectly by

    the author and by the use of this document.

    The Environmental Impact Assessment Regulations (Regulation 17 of Government Notice No. R345 of 2010), requires

    that certain information is included in specialist reports. The terms of reference, purpose of the report, methodologies,

    assumptions and limitations, impact assessment and mitigation (where relevant to the scope of work) and summaries

    of consultations (where applicable) are included within the main report. Other relevant information is set out below:

    Expertise of author:

    Working in the field of ecology, and in specific vegetation related assessments, since 2007;

    Is registered as a Professional Natural Scientist with the South African Council for Natural Scientific

    Professions in the field of ecology (Reg. No. 400019/11); and

    Has been working with plants indigenous to South Africa since 1997.

    Declaration of independence:

    Dimela Eco Consulting in an independent consultant and hereby declare that it does not have any financial or other

    vested interest in the undertaking of the proposed activity, other than remuneration for the work performed in terms of

    the National Environmental Management Act, 1998 (Act 107 of 1998). In addition, remuneration for services provided

    by Dimela Eco Consulting is not subjected to or based on approval of the proposed project by the relevant authorities

    responsible for authorising this proposed project.

    Disclosure:

    Dimela Eco Consulting undertake to disclose, to the competent authority, any material information that has or may have

    the potential to influence the decision of the competent authority or the objectivity of any report, plan or document

    required in terms of the National Environmental Management Act, 1998 (Act 107 of 1998) and will provide the

    competent authority with access to all information at its disposal regarding the application, whether such information is

    favourable to the applicant or not.

    Based on information provided to Dimela Eco Consulting by the client, and in addition to information obtained during

    the course of this study, Dimela Eco Consulting present the results and conclusion within the associated document to

    the best of the authors professional judgement and in accordance with best practise.

    _________________________________ _____29/07/2015______

    Antoinette Eyssell-Knox Date

    SACNASP Reg. No. 400019/11

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    i

    EXECUTIVE SUMMARY

    Eskom has appointed Mokgope Consulting to undertake an Environmental Impact Assessment

    of the “Proposed Northern Alignment 765kV Powerline Project”. The length of the route is

    approximately 800km from Juno to Helios to Aries to Kronos to Perseus substations. As part of

    the Environmental Impacts Assessment (EIA) process, Mokgope Consulting appointed Dimela

    Eco Consulting to undertake a vegetation assessment of the areas that could be affected by the

    construction and operation of the proposed infrastructure and to indicate which of the proposed

    corridors will have the least impact on natural vegetation and sensitive ecological features (e.g.

    ridges and wetlands). This report presents the findings of the proposed Helios-Juno sub-project.

    The proposed powerline corridors stretch from the Helios substation about 50km north of the town

    of Loeriesfontein in the Northern Cape Province, to the Juno substation situated between the

    towns of Lutzville and Vredendal in the Western Cape Province and will traverse through fifteen

    national vegetation types that are mapped at a broad scale. Of these the Vanrhynsdorp

    Gannabosveld is considered to be vulnerable to extinction. The literature review indicated that

    the corridors, especially within the Knersvlakte, comprise a number of sensitivities that should be

    regarded as development constraints. Corridor 3 and Corridor 2 will traverse or come in close

    proximity of the Moedverloren (Knersvlakte) Nature Reserve, while most of the proposed Helios-

    Juno powerline routes pass through Knersvlakte Hantam focus areas for the expansion of

    protected areas. It is advised that electrical infrastructure in this area be planned in consultation

    with the South African National Biodiversity Institute (SANBI) as well as the Department of

    Environmental Affairs (DEA) and CapeNature. In addition, Critical Biodiversity Areas (CBAs) as

    well as Ecological Support Areas (ESAs) occur within all three of the Helios-Juno Corridors.

    Additional sensitivities included areas of high botanical sensitivity within all three corridors, as well

    as farms with a high irreplaceability index within Corridor 3. In July 2015, after the report was

    drafted, Eskom proposed deviations to Corridor 3. This report was thus updated in July 2015 with

    the new deviations.

    Based on the field survey and the literature reviewed, the vegetation that could be impacted on

    by the proposed powerline corridors were classified into six (6) broad vegetation groupings. A

    summary of the broad vegetation groupings and their sensitivity to the proposed powerline

    development are as follows:

    Broad vegetation

    grouping Summary

    Succulent Karoo

    The southern extent of the corridors is situated within the Succulent Karoo vegetation

    group and were characterised by dwarf to low shrubland with a high frequency of

    succulent plants, especially vygies and crassulas. The vegetation is dominated by

    leaf succulents and some shrubs spread amongst the succulents. The grass layer is

    limited as well as tall shrubs and trees. The dominant vegetation displayed is mainly

    members of the Mesembryanthemaceae. Argyroderma species (dwarf compact

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    ii

    Broad vegetation

    grouping Summary

    plants resembling pebbles) as well as Crassula- and Aloe species are widespread in

    this vegetation group. Within the Vygieveld, varied habitats occur, which lead to

    another subdivision of the Vygieveld group into Quartz Vygieveld, Shale Vygieveld

    and Northern & Central Vygieveld. All areas supporting extensive surface stone or

    rock and have been rated as having a high sensitivity and regional conservation

    value. The two main vegetation types with significant surface stone or rock

    (Knersvlakte Dolomite Vygieveld and Knersvlakte Quartz Vygieveld, and their

    subtypes) are the core element of the world renowned plant diversity of the

    Knersvlakte, and are home to a very high proportion of the many rare and localised

    plant species; the dwarf succulents and bulbs characteristic of these units are very

    sensitive to soil disturbance, and to being crushed by machinery or even by human

    feet; rehabilitation potential of rocky and stony habitats is very low or negligible (but

    is considered feasible in areas with deeper soils); and most of the study area is a

    terrestrial Critical Biodiversity Area.

    Conservation is now the primary land use in at least 25% of the Knersvlakte, and is

    rapidly replacing sheep farming as the primary land use throughout the region

    Gannabos

    Within the Knersvlakte, the Vanrhynsdorp Gannabosveld support succulent

    shrubland that is dominated by Salsola species. Salsola plants are commonly referred

    to as saltwort or Gannabos, due to their ability to tolerate high salt conditions in soils.

    The Gannabos is found on silty soils, and has already lost at least 21% of its original

    total regional extent (mostly to gypsum mining and agriculture), and is consequently

    listed as a Vulnerable vegetation type. A number of endemic species (species

    restricted to this vegetation type) occur here including Eriospermum eriophorum

    which is a Critically Endangered species, as well as the Vulnerable specie Euphorbia

    fasciculata, Cotula pedunculata and Brownanthus glareicola.

    Mixed Karoo

    This vegetation group comprised the grouping of vegetation that is predominantly arid

    grassland and vegetation that is predominantly dwarf shrubveld as well as the where

    these vegetations intersperse. This mixed vegetation is a mixture of Karoo bossies

    (

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    iii

    Broad vegetation

    grouping Summary

    From Helios south-westward, the corridors pass through the Hantam Karoo which

    was also grouped into the Mixed Karoo as it comprises a mixture of succulents (Aloe,

    Euphorbia, and Ruschia) and dwarf, karroid shrubs with small leaves (Eriocephalus,

    Pentzia and Pteronia). This vegetation occurs west of Loeriesfontein and extends into

    the Western Cape.

    A large extent of the typical vegetation encountered still exists nationally and this

    vegetation is currently regarded by the National Spatial Biodiversity Assessment as

    least threatened nationally. Both substations are situated in the Mixed-Karoo

    vegetation group. However, it must be noted that numerous solar and wind farms are

    proposed to be developed within this vegetation group and that cumulative impacts

    could lead to a decrease in the natural extent of the Mixed-Karoo.

    Vegetation on rocky

    outcrops, ridges,

    inselbergs

    The vegetation on rocky areas in proximity to Helios substations could include the

    Rare succulent Conophytum corcodans. Trees were limited or completely absent

    from the landscape. Although, from here the corridors pass through a mountainous

    area that includes succulents such as the Vulnerable Aloe dichotoma (Tree

    Aloe)(mostly on north facing slopes) the Endangered Aloe pillansii (Bastard Quiver

    Tree), as well as Pachypodium namaquanum (Halfmens). About 35km south-west of

    the Helios substation, all three corridors pass through the Namaqualand Klipkoppe

    Shrubland which is associated with huge granite and gneiss domes and boulder

    koppies. The vegetation includes tall shrubs (1m) but is dominated by dwarf to

    medium sized shrubs with small or succulent leaves. Corridor 3 includes portions of

    the Kammiesberg Mountain Shrubland which is structurally very similar and also has

    species in common with the Namaqualand Klipkoppe Shrubland. It was found that a

    significant number (>25) of endemic species occur primarily or wholly within these

    two vegetation types.

    The vegetation on ridges, inselbergs, rocky outcrops and koppies are known to

    comprise higher species diversity and therefore their protection contributes to

    conservation of biodiversity.

    Riparian vegetation

    Much of the riparian areas observed at the time of the field survey were being utilised

    for agricultural purposes such as cultivation and grazing. In addition, the alien invasive

    weeds Prosopsis glandulosa and Tamarix species were found to have invaded large

    extents of riparian habitat. About 60km south-west of the Helios substation, all three

    corridors traverse the Namaqualand Riviere vegetation type which is restricted to the

    seasonal river valleys and floodplains throughout the Namaqualand region. The

    vegetation unit is listed as Least Threatened, even though at least 17% of its original

    total. The vegetation grows in the dry riverbeds and banks of the intermittent rivers

    and comprises shrubland with an abundance of halophytes (salt tolerant species)

    such as Suadea fructicosa, Limonium dregeanum and Salsola species. Trees and tall

    shrubs occur in riparian thickets and include Acacia karoo (Sweetthorn), Melianthus

    pectinatus and Searsia burchelii. Grasses and sedges also occur.

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    iv

    Broad vegetation

    grouping Summary

    Vegetation within the riverbeds is invaluable when sporadic high rainfall events do

    occur. The vegetation stabilises the soil and keep it from washing away, preventing

    degradation of the non-perennial rivers and sedimentation further downstream.

    Riparian areas are protected by legislation and impacts on riparian areas as well as

    a regulated buffer zone should be avoided.

    Vegetation

    associated with pans

    The pans within the area studies are large depressions of marine origin with white to

    grey silt and clay soils corridors and occasionally support sparse vegetation

    comprising of salt tolerant shrubs such as Salsola and Malephora species. The pans

    are mostly dry and can disappear under layers of wind-blown sand Pans (being a

    type of wetland) are protected by national legislation and therefore should be

    regarded as sensitive to developments. If the proposed powerline infrastructure can

    span the pan areas, it is assumed that the impact of the development on pans would

    be low or negligible. However, note that activities within 500m of a wetland

    (Regulation 1199 of the National Water Act, 1998 (Act 36 of 1998) are subjected to a

    Water Use License.

    Preferred route options:

    This report found that all three Corridors are sensitive to the proposed development as they

    traverse protected areas and areas with significant botanical value within the Knersvlakte. This

    report suggests a combination of Corridor 1 and 2, with Deviation 1F and 1G to be ground-truthed

    as a potential final corridor, or that Corridor 1 with Deviation 1E and 1G, where an existing

    powerline is situated in, are further researched. Corridor 1 will limit the need for access roads if

    the proposed powerline is placed in close proximity to the existing powerline. However, Corridor

    1 will need to be thoroughly ground-truthed during the growing and flowering period of plants in

    the area (mainly winter) in order to avoid localised sensitivities that is known to occur within this

    corridor. It is recommended that the route be ground-truthed once the tower positions is known,

    in order for the specialist to advise whether tower positions needs to move from localised

    sensitivities.

    The precautionary principle suggests in this case that all rocky and stony areas in the Knersvlakte

    should be considered highly sensitive to disturbance and effectively unrehabilitable, and that the

    burden of proof to the contrary should rest on the applicant or proponent of any disturbance.

    Both substations are situated in vegetation groupings of medium sensitivity. Although localised

    sensitivities are to be expected along all the route corridors (e.g. occurrence of threatened plant

    species), this study was broad scales and the final route alignment should be ground-truthed, and

    be allowed to deviate to accommodate the conservation of such local sensitivities by small

    diversions.

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    v

    Plants of Conservation Concern

    At least 140 plant species of conservation concern could occur within the proposed corridors.

    About half these are currently listed as Rare, in that they are not known to be currently threatened

    by any ongoing pressures, and the remainder are listed as threatened, with the main pressures

    being mining and/or prospecting (gypsum, diamonds, rare earths, dolomite), agriculture (in

    Vanrhynsdorp Gannabosveld and Namaqualand Spinescent Grassland) and very low population

    numbers and/or extremely localised populations.

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    vi

    TABLE OF CONTENTS

    EXECUTIVE SUMMARY ................................................................................................................................... i

    1. INTRODUCTION ............................................................................................................................. 1

    1.1 Terms of reference ........................................................................................................................ 1

    1.2 Assumptions and Limitations ........................................................................................................ 2

    1.3 Methodology ................................................................................................................................. 2

    2. BACKGROUND TO THE STUDY SITE ............................................................................................... 4

    2.1 Locality ........................................................................................................................................... 4

    2.2 Climate ........................................................................................................................................... 5

    2.3 Topography and Hydrology ........................................................................................................... 7

    2.4 Protected Areas and Protected Areas Expansion .......................................................................... 7

    2.6 Succulent Karoo Ecosystem Programme (SKEP).......................................................................... 11

    2.7 Expected Vegetation and Related Conservation Status .............................................................. 13

    2.7.1 Biomes ................................................................................................................................. 13

    2.7.2 Broad-scale Vegetation Types (National Vegetation Map)................................................. 14

    2.8 Listed Ecosystems ........................................................................................................................ 14

    3. RESULTS OF THE FIELD ASSESSMENT .......................................................................................... 17

    3.1 Broad Vegetation Groupings ....................................................................................................... 19

    3.1.1 Succulent Karoo .................................................................................................................. 19

    3.1.2 Gannabos ............................................................................................................................ 24

    3.1.3 Mixed-Karoo vegetation ..................................................................................................... 25

    3.1.4 Vegetation on hills .............................................................................................................. 27

    3.1.5 Riparian vegetation ............................................................................................................. 30

    3.1.6 Namaqualand Salt Pans and associated vegetation ........................................................... 31

    3.2 Plants of Conservation Importance ............................................................................................. 31

    3.2.1 Nationally Protected Plant (Plants of Conservation Concern) ............................................ 31

    3.2.2 Provincially Protected Plants .............................................................................................. 33

    3.3 Alien Invasive Plant Species ......................................................................................................... 33

    4. Vegetation Importance and Sensitivity ....................................................................................... 35

    4.1 Sensitivity Ratings and Analysis ................................................................................................... 35

    4.2 Vegetation Sensitivity .................................................................................................................. 36

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    vii

    4.2.1 Vegetation of Medium Sensitivity ....................................................................................... 36

    4.2.2 Vegetation and areas of High Sensitivity ............................................................................ 37

    5. Comparison of route ALTERNATIVES ........................................................................................... 42

    6. IMPACT ASSESSMENT AND MITIGATION .................................................................................... 45

    6.1 Potential Impacts of Powerlines on Vegetation .......................................................................... 45

    6.2 Impact Assessment Criteria ......................................................................................................... 47

    6.3 Impacts Assessment .................................................................................................................... 50

    6.4 Mitigation Measures ................................................................................................................... 55

    6.4.1 Destruction of natural vegetation ....................................................................................... 55

    6.4.2 Exposure to erosion ............................................................................................................ 57

    6.4.3 Removal / Destruction of protected plants and plants of conservation concern .............. 58

    6.4.4 Potential increase in invasive vegetation ........................................................................... 59

    6.4.5 Positive impact by removing alien invasive plants ............................................................. 59

    6.4.6 Disturbance to non-perennial and perennial rivers ............................................................ 60

    6.4.7 Soil compaction and disruption of quartz fields ................................................................. 61

    6.4.8 Impact on protected areas .................................................................................................. 61

    6.4.9 Deterioration of natural vegetation and bush encroachment ........................................... 62

    6.4.10 Destruction of natural vegetation ....................................................................................... 63

    6.4.11 Possible increase in exotic vegetation ................................................................................ 63

    7. CONCLUSION ............................................................................................................................... 63

    8. REFERENCES................................................................................................................................. 65

    9. GLOSSARY .................................................................................................................................... 69

    APPENDIX A: SAMPLE AREAS MAP ............................................................................................................. 73

    APPENDIX B: METHODOLOGY ..................................................................................................................... 74

    APPENDIX C: SPECIES OF CONSERVATION CONCERN THAT COULD OCCUR WITHIN THE PROPOSED

    CORRIDORS .................................................................................................................................. 76

    APPENDIX D: RATING OF ROUTE ALTERNATIVES ........................................................................................ 78

    APPENDIX E: ADDITIONAL BOTANICAL INPUT REPORT, NICK HELME (2013) ............................................. 81

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    viii

    TABLES

    Table 1: Vegetation types that occur within the study area....................................................................... 15

    Table 2: Vegetation groupings observed compared to the National Vegetation Map (Mucina &

    Rutherford, 2006) ........................................................................................................................ 18

    Table 3: Weighting scores ........................................................................................................................... 35

    Table 4: Scoring of vegetation that occur within the study area ................................................................ 36

    Table 5: Route Alignment comparison and order of preference ................................................................ 44

    Table 6: Assessment of the likely impacts associated with the construction phase of the powerline from

    Helios to Juno substation ............................................................................................................ 50

    Table 7: Assessment of impacts associated with the operational phase of the powerline from Helios to

    Juno substation............................................................................................................................ 54

    FIGURES

    Figure 1: Locality of the proposed corridor alternatives .............................................................................. 6

    Figure 2: Protected areas, protected areas expansion focus areas, as well as Critical Biodiversity Areas

    and Ecological Support Areas along the proposed corridors and deviations to corridor 1 .......... 9

    Figure 3: Planning domain of SKEP indicating the Knersvlakte and Moedverloren (Knersvlakte) Nature

    reserve (http://bgis.sanbi.org/skep/project.asp)........................................................................ 12

    Figure 4: Vegetation types present along the proposed Helios-Juno route corridors ............................... 16

    Figure 5: Broad vegetation groupings within the proposed Helios-Juno corridors .................................... 20

    Figure 6: Topographic features common in the Karoo (picture taken from Esler et al, 2006) ................... 28

    Figure 7 Threatened species and species of conservation concern ........................................................... 32

    Figure 8: Other sensitivities within the Helios-Juno corridors and proposed deviations to corridor 1...... 41

    Figure 9: Deviation 1E avoids the area of high botanical sensitivity associated with the mountainous area

    (Google Earth imagery) Sensitivity as per Helme (2013) ............................................................. 42

    Figure 10: Deviation 1G crosses a small quartz patch that must be avoided by the line (Google Earth

    imagery) Sensitivity along 1G as received from N Helme on 23/7/2015 .................................... 42

    LIST OF PHOTOGRAPHS

    Photograph 1: View of the Knersvlakte from Vanrhyns Pass ....................................................................... 7

    Photograph 2: Quartz Vygieveld with Argyroderma and Crassula species................................................. 21

    Photograph 3: Brunsvigia within Corridor 1 – note existing powerline in the background - arrow ........... 22

    Photograph 4: (Northern) Vygieveld in Corridor 3 ..................................................................................... 23

    Photograph 5: Vygieveld during the dry summer (top) and after good winter rains (bottom) (pictures

    from Helme, 2013) ...................................................................................................................... 24

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    ix

    Photograph 6: Vegetation around the Juno substation, note the deeper soil (right) ................................ 25

    Photograph 7: Sparse vegetation in the Helios substation vicinity. Note existing pylons in Corridor 1 & 2

    ..................................................................................................................................................... 27

    Photograph 8: Typical inselbergs within the Mixed-Karoo vegetation grouping ....................................... 29

    Photograph 9: Namaqualand Klipkoppe Shrubland with Vygieveld in the foreground (within Corridor 3,

    close to the N7 highway) ............................................................................................................. 30

    Photograph 10: From Helme (2013): Four Knersvlakte limestone endemics co-occurring in less than

    0.1m2! The three clump forming vygies are all species of Antimima (A. evoluta, A. turneriana,

    A. fenestrata), and the geophyte Bulbine margarethae is at top right. Some of these plants may

    be at least forty years old. Photographed on Varsche Rivier Extension B (within Corridor 1). .. 32

    Photograph 11: Eriospermum arachnoideum (spiderweb cottonseed) is a summer flowering geophyte

    with a very characteristic winter growing leaf, and is restricted to a handful of Knersvlakte

    limestone localities. The species is never common at any locality, and is Red Listed as

    Endangered (Raimondo et al 2009). ............................................................................................ 33

    Photograph 12 From Helme (2013): View of damage caused to a quartz field by a single pass of a tractor

    more than two years previously (photo taken in Knersvlakte Quartz Vygieveld). The quartz sits

    on top of a soft and erodible soil layer, and the survival of most succulents in this habitat is

    dependent on the quartz layer being left intact and undisturbed. Heavy vehicles used for

    powerline installation could result in large areas of similar or worse damage, as they may need

    to follow a lines not supported by existing tracks. ...................................................................... 46

    Photograph 13: From Helme (2013): Closeup of a healthy, undisturbed quartz patch, as indicated by

    abundant lichens, and dwarf shrubs in background (top) and (bottom) an adjacent area that

    has been sterilised by occasional (a couple of times per year) use as a parking area for light

    vehicles – note the complete lack of lichens and shrubs, and lack of micro - topography......... 47

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    1

    1. INTRODUCTION

    Eskom has appointed Mokgope Consulting to undertake an Environmental Impact Assessment

    of the “Proposed Northern Alignment 765kV Powerline Project”. The length of the route is

    approximately 800km from Juno to Helios to Aries to Kronos to Perseus substations.

    Due to the lengthy proposed route, the project has been sub-divided into four sub-projects which

    are:

    The proposed Helios-Juno 765kV Transmission Powerline and substations upgrade, Northern

    Cape Province.

    The proposed Aries-Helios 765kV Transmission Powerline and substations upgrade, Northern

    Cape Province.

    The proposed Aries-Kronos 765kV Transmission Powerline and substations upgrade, Northern

    Cape Province.

    The proposed Kronos-Perseus 765kV Transmission Powerline and substations upgrade, Northern

    Cape and Free State Provinces.

    Three corridors are proposed to be assessed to find the corridor and route that will have the least

    impact on the Environment. As part of the Environmental Impacts Assessment (EIA) process,

    Mokgope Consulting appointed Dimela Eco Consulting to undertake a vegetation assessment of

    the areas that could be affected by the construction and operation of the proposed infrastructure

    and to indicate which of the proposed corridors will have the least impact on natural vegetation

    and sensitive ecological features (e.g. ridges and wetlands). This report presents the findings of

    the proposed Helios-Juno sub-project.

    In July 2015, after the original report was drafted, Eskom proposed deviations to Corridor 1. This

    report was thus updated in July 2015 with the new deviations. Thus these deviations were not

    known at the time of the site visit and were not ground-truthed.

    1.1 Terms of reference

    The terms of reference was interpreted as follows:

    Field survey with specific reference to sensitive habitats and potential habitats for plants of

    conservation concern that could occur along the proposed powerline corridors. Due to the

    large area assessed, the field survey focussed on verifying land uses that likely impacted

    on primary vegetation, thereby delineating areas where primary and thus likely sensitive

    vegetation remains;

    Compare the floral assemblages that are expected to occur within the corridors to the actual

    vegetation found to be present along the proposed corridor options;

    Map the localities of plants of conservation concern that were identified during the field

    survey or suitable habitat where these plants could potentially occur;

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    2

    Assess the possible impacts that the proposed construction and operation of a transmission

    line could have on the surrounding vegetation,

    Recommend the corridor that is likely to have the least impact on sensitive vegetation, and

    Recommend mitigation measures to aid the conservation of vegetation during construction

    and operation.

    1.2 Assumptions and Limitations

    In order to obtain a comprehensive understanding of the vegetation composition and species

    present along the proposed corridors, including identification of species of conservation concern

    (also called Red data plants) studies should include seasonal assessments through the year and

    over a number of years. This helps to identify trends, account for seasonal variability and to

    capture data in favourable growing conditions. In order to identify as much flowering species as

    possible, two field assessments should be undertaken during the growing period of plants e.g.

    winter in the winter rainfall areas. However, this assessment comprised of only a single site visit

    during April 2013 to gain a strategic overview of potential and confirmed vegetation and ecological

    sensitive features within the proposed corridors.

    The area studied experience early autumn rainfall around the Helios substation and winter rainfall

    through much of the remainder of the corridors situated in the Western Cape. Prior to this survey

    (early April), the Northern Cape Province received some rainfall over the Easter weekend.

    However, the preceding months were mostly dry and the rainfall received at the time did not

    contribute greatly to species identification. Much of the vegetation was dry and many areas along

    the corridor were found to be used for grazing, with just a few grasses and shrubs in flower.

    Local variations in the vegetation are not always distinguishable on the broad scale assessment

    undertaken or on aerial photographs. Due to the extent of the proposed powerline corridor, the

    time and budget constraints, as well as inaccessibility of large portions of vegetation within the

    proposed corridors, comprehensive mapping of all the different vegetation communities present

    in the study area was not feasible as this can only be accomplished through thorough sampling.

    Although the vegetation observed along the corridors could be subdivided into numerous smaller

    vegetation units or plant communities, this would have involved numerous sampling points within

    the proposed corridors. For a project of this extent, extended time on site and thorough sampling

    would be costly and was deemed unfeasible at this stage of the impact assessment. In addition,

    a large extent of the proposed corridors traversed through the Knersvlakte which is a sensitive

    vegetation habitat. The area receives winter rainfall and at the time of the study, limited rainfall

    was experienced and therefore the vegetation was sparse with only a few species in flower.

    1.3 Methodology

    The study was undertaken during the week of 15 April 2013. The assessment entailed a literature

    review which included short listing plants of conservation concern that could potentially occur

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    3

    along the proposed routes, a field visit, the analysis of data collected during the field survey as

    well as the literature review and reporting.

    Literature Review:

    The description of the regional vegetation relied on literature from Mucina & Rutherford (2006).

    Plant names followed Le roux, (1994), Shearing (1994), Van Wyk & Van Wyk (1997), Van Wyk &

    Malan (1997), Pooley (1998), Henderson (2001), Van Oudtshoorn (2002), Van der Walt (2004),

    Anderson (2011a), Anderson, (2011b) and Bromilow (2010). In the absence of biodiversity

    assessment guidelines in the Northern Cape Province, this study was undertaken in accordance

    with the Gauteng Minimum Requirements for Biodiversity Assessment (GDARD, 2012) as best

    practice guideline. In addition, the Western Cape Guideline for involving biodiversity specialists in

    EIA processes was also consulted (Brownlie, 2005). During the literature survey it was noted that

    the corridors traversed the Knersvlakte. This area is a biodiversity hot-spot and is known for

    supporting a high number of threatened plant species. As precautionary measure, a botanist with

    extensive knowledge and experience of the area, Nick Helme, was also consulted (Helme, 2013).

    Field survey:

    The field survey focussed on identifying natural and untransformed vegetation, unique features

    that could indicate local sensitivities such as threatened and protected plants, as well as sensitive

    ecological features such as wetlands, ridges and rivers that are essential for the maintenance of

    ecosystems and ecological processes and which is likely to support plant species of conservation

    concern. Sampling was undertaken randomly in accessible areas within the 2km wide proposed

    corridors. A map of the sampling areas is given in Appendix A. Any additional information on any

    other feature thought to have ecological significance within sampling areas, such as dominant

    species vegetation cover, soil type, erosion, rocky cover, alien/exotic/invasive plants, as well as

    plant species of conservation concern and/or their habitat was also recorded. Plant identification

    and vegetation description relied on species recorded in the sampling areas, as well as relevant

    literature and distribution data. As the deviations to Corridor 1 were added after the field survey,

    the assessment of this portion relied mainly on the literature review.

    Vegetation Sensitivity

    For the purpose of this study, the identification and basic descriptions of vegetation that are

    presented in this document should be adequate to highlight the likely status and sensitivities

    associated with the respective vegetation groups observed along the proposed corridors, as well

    as evaluating the possible impacts that will result from the proposed development. The criteria

    and weighting scores used to determine the vegetation sensitivity, function and conservation

    importance are given in Appendix B. Vegetation and ecological features protected by law e.g.

    watercourses and protected areas were regarded as sensitive along with primary vegetation and

    vegetation that were confirmed to support or is highly likely to support plants of conservation

    concern (e.g. ridges).

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    4

    2. BACKGROUND TO THE STUDY SITE

    2.1 Locality

    The proposed powerline corridors stretch from the Helios substation about 50km north of the town

    of Loeriesfontein in the Northern Cape Province, to the Juno situated between the towns of

    Lutzville and Vredendal in the Western Cape Province (Figure 1). Helios substation is within the

    jurisdiction of the Hantam Local Municipality and the Namakwa District Municipality, while Juno

    substation is situated in the Matzikama Local Municipality and the West Coast District

    Municipality. Three route corridors are proposed, of which one route will be implemented based

    on the least detrimental impacts (Figure 1).

    Route Corridors:

    Corridor 1: From the Helios substation, Corridor 1 aligns with the dirt road (access road to Helios

    substation from Loeriesfontein) for about 30km. From here Corridor 1 joins Corridor 2 for about

    13km. This portion also includes an existing transmission line. Hereafter, Corridor 1 splits

    southwards from Corridor 2 and includes the existing powerline up to Juno substation (Figure 1).

    For parts of this corridors extent, it comes into close proximity to Sishen-Saldana railway line.

    Deviation 1E: This route follows the same alignment as Corridor 1 for the first 65km. After crossing the

    R355 road, Corridor 1 crosses over a mountainous area that include areas of high botanical sensitivity.

    However, deviation 1E by-passes the mountain to its west, aligning between the mountain and the Krom

    River and re-joins corridor 1 after the mountainous area. This route was proposed due to erosion issues

    and to avoid the mountainous terrain.

    Deviation 1F: This deviations links Corridor 1 and 2 and was pproposed by the vegetation specialist in

    the original assessment (Dimela Eco Consutling, 2013) as an alternative to avoid sensitive vegetation.

    The preferred route east of this link would thus be Corridor 2, and west of this link Corridor 1 (within the

    servitude of the existing line) would be preferred.

    Deviation 1G: This route follows the same alignment as Corridor 1 for the majority of the route. However,

    where corridor 1 crosses the N7 highway (north of Vanrhynsdorp), deviation 1G splits from Corridor 1for

    about 10km before it re-joins it again. This deviation comprises a 4km corridor as both CapeNature and

    the Avifauna Specialist have proposed two different deviations within that 4km Corridor.

    Corridor 2: From the Helios substation, Corridor 2 remains between Corridor 1 and 3. This corridor

    includes an existing transmission line. Corridor 2 joins Corridor 1 and Corridor 3 after the initial

    30km and aligns over the Bokkeveldberge. After about 28km, Corridor 3 splits southwards (and

    with it the existing powerline), while Corridor 1 and Corridor 2 align together for another

    approximate 22km. Before the Moedverloren (Knersvlakte) Nature Reserve, Corridor 2 splits from

    Corridor 1 and align more east. After is crosses over the N7 road, this corridor joins Corridor 3 for

    the remaining 15km to Juno substation (Figure 1). For parts of this corridors extent, it comes into

    close proximity to Sishen-Saldana railway line.

    Corridor 3: From the Helios substation, Corridor 3 is the most northern corridor. After the initial

    30km form the Helios substation, this corridor joins Corridor 2 and Corridor 1 for about 28km, over

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    5

    the Bokkeveldberge. West of Loeriesfontein, Corridor 1 and Corridor 2 align more northwards and

    join for another approximate 22km. From here Corridor 2 splits more southward and Corridor 3

    traverses through the Moedverloren (Knersvlakte) Nature Reserve. About 10km after crossing

    over the N7 road, Corridor 3 turns southwards to reach the Juno substation about 32km further

    (Figure 1).

    2.2 Climate

    The Northern Cape Province is considered semi-arid and the western portion of this province

    receives rainfall in winter, whereas the eastern portion usually receives summer rainfall. Rainfall

    increases to the east of the province and average approximately 400mm per annum. The area

    studied around Loeriesfontein, receives autumn and winter rainfall of about 200mm per year.

    Temperatures can reach 40°C in summer, while frost and temperatures below 0°C are recorded

    in winter. Whirl winds are common on hot days.

    The portion of the proposed powerline routes situated within the Western Cape receives winter

    rainfall. Rainfall is low, between 100 and 200mm per year and very dry in summers. Average

    temperatures can range from 35°C in summer to between 5 and 10°C in winter (Mucina &

    Rutherford, 2006). During summer, temperatures in excess of 40°C are common. Fog is common

    nearer the coast. Frost is infrequent.

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    6

    Figure 1: Locality of the proposed corridor alternatives

    Corridor 1

    Corridor 2

    Corridor 3 Deviation 1E

    Deviation 1F

    Deviation 1G

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    7

    2.3 Topography and Hydrology

    The Provinces comprise mainly of flat to undulating landscapes. The western extent of the

    proposed powerline routes covers a flat to gently undulating plain, with some hilly and "broken"

    veld, mostly situated to the west and south of the escarpment. The Juno substation is situated at

    an altitude of 90m, while the Helios substation is situated much higher at an altitude of 930m.

    From Juno substation, the corridors thus traverse mountainous areas (Kammiesberg Mountains

    / Bokkeveld Mountain). Photograph 1 shows the significant drop in altitude as viewed from the

    Vanrhyns Pass towards the Juno substation. Pans can characteristically be observed within

    depressions and riparian areas along the lowest points in the landscape. The proposed powerline

    routes will cross numerous perennial and non-perennial rivers and drainage lines. Perennial rivers

    include: Doring River, Twee Rivier, Spitskop Rivier, Sout (Salt) Rivier, Geelbeksrivier and

    Holrivier.

    Photograph 1: View of the Knersvlakte from Vanrhyns Pass

    2.4 Protected Areas and Protected Areas Expansion

    Protected Areas

    Protected areas (PAs) in South Africa should be regarded as sensitive to developments. South

    Africa’s legislated PAs are grouped as the following types:

    Type 1: includes National Parks, Provincial Nature Reserves, Local Authority Nature

    Reserves and Department of Forests and Fisheries’ Forest Nature Reserves Forest

    Nature Reserves.

    Type 2: includes Mountain Catchment Areas, Wildlife Management Areas, private nature

    reserves, National Heritage Sites, Department of Forestry and Fisheries (DAFF) Forest

    Areas, South African Defence Force (SANDF) property, bird sanctuaries, and botanical

    gardens.

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    8

    Type 3: includes game farms, private game reserves and conservancies.

    Corridor 3 will traverse large sections of the Moedverloren (Knersvlakte) Nature Reserves, while

    Corridor 2 will cut through small portions thereof (Figure 2).

    Protected Areas Expansion Strategy

    South Africa’s PA network currently falls far short of sustaining biodiversity and ecological

    processes and therefore the National Protected Area Expansion Strategy (NPAES) are being

    implemented (DEA, 2009). The NPAES was commissioned by the Department of Environmental

    Affairs (DEA), co-ordinated by the South African National Biodiversity Institute (SANBI), and

    drafted in close collaboration with the South African National Parks (SANParks), other national

    conservation agencies and the Provincial conservation agencies. A project team comprising

    SANBI, SANParks and DEAT provided oversight to specialist consultants contracted to draft the

    strategy. The goal of the NPAES is to achieve cost effective protected area expansion for

    ecological sustainability and increased resilience to climate change. The NPAES sets targets for

    PA expansion, provides maps of the most important areas for PA expansion, and makes

    recommendations on mechanisms for PA expansion. The NPAES uses two factors, importance

    and urgency, to identify priority areas for PA expansion in the terrestrial environment. Although

    not currently protected, these areas should be considered as being of high development

    constraint for infrastructure proposed to be located within or in close proximity to these areas.

    Most of the proposed Helios-Juno powerline routes pass through Knersvlakte Hantam focus areas

    for the expansion of protected areas (Figure 2). Therefore, it is advisable that any electrical

    infrastructure in this area be planned in consultation with the South African National Biodiversity

    Institute (SANBI) as well as the Department of Environmental Affairs (DEA) and CapeNature.

    As per Helme (2013): “Given its global significance as a biodiversity hot-spot (Cowling and Pierce

    1999), and its long-standing recognition as a regional conservation priority (Hilton-Taylor 1994a,

    Rebelo 1994), the current protected area system in the Succulent Karoo is woefully inadequate.“

  • Oct 2013 Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    9

    Figure 2: Protected areas, protected areas expansion focus areas, as well as Critical Biodiversity Areas and Ecological Support Areas

    along the proposed corridors and deviations to corridor 1

    1E

    1F

    1G

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    10

    Only 2.1% or 2 352km² of the Succulent Karoo is conserved in six statutory reserves (Hilton-

    Taylor 1994a). Larger reserves (>10 000 ha) occur in only four of the Succulent Karoo’s 12

    bioregions and conserve only 80 (9%) of its 851 Red Data Book plant species (Lombard et al.

    1999).

    “...there has been substantial investment in the area by the Leslie Hill Succulent Karoo Trust,

    which is administered by and is the primary funding source for the WWF (World Wildlife Fund -

    SA) projects in the Succulent Karoo region of South Africa. There are currently at least eighteen

    significant properties (portions, remainders and original farms) in the Knersvlakte owned by WWF

    – SA and managed by the state conservation organisation CapeNature. These areas are all

    regarded and managed as declared nature reserves and are in the final stages of being

    proclaimed as Provincial Nature Reserves. Nature conservation and protection of the unique

    biodiversity (and especially the dwarf succulent plants) on these properties is the primary reason

    why these properties were acquired from the original landowners. Conservation is now the

    primary land use in at least 25% of the Knersvlakte, and is rapidly replacing sheep farming as the

    primary land use throughout the region (pers. obs.).” (Helme, 2013)

    2.5 Municipal Biodiversity Sector Plans

    The corridors within the Namakwa District Municipality (Northern Cape Province) of the Helios

    Juno line are included in the Namakwa Biodiversity Sector Plan (Desmet & Marsh, 2007). This

    comprises the area from Helios substation to the border of the Western Cape and Northern Cape

    provinces, a distance of about 75km. The remainder of the corridors to Juno substation is situated

    within the Matzikama District Municipality which is included in the Biodiversity Sector Plan for the

    Saldanha Bay, Bergrivier, Cederberg and Matzikama Municipalities (Maree & Vromans, 2010).

    However, the Bokkeveld portion of the Hantam Municipality (including the corridors situated within

    this municipality) was also included in the Biodiversity Sector Plan for the Saldanha Bay,

    Bergrivier, Cederberg and Matzikama Municipalities and therefore, only this sector plan is referred

    to here (Maree & Vromans, 2010). The Sector Plan maps areas of biodiversity concerns to ensure

    that biodiversity information can be accessed and utilized by local municipalities to inform land

    use planning and development as well as the decision making processes within the municipalities.

    The biodiversity maps indicate where Critical Biodiversity Areas (CBAs) as well as Ecological

    Support Areas (ESAs) occur within the Helios-Juno Corridors (Figure 2).

    Critical Biodiversity Areas (CBA) are those terrestrial (land) and aquatic (water) areas which must

    be safeguarded in their natural state as they are critical for conserving biodiversity pattern and

    maintaining ecosystem functioning (Maree & Vromans, 2010). These areas include:

    a) Areas requiring safeguarding in order to meet national biodiversity thresholds;

    b) Areas required to ensure the continued existence and functioning of species and

    ecosystems, including the delivery of ecosystem services; and/or

    c) Special Habitats or locations where Species of Special Concern occur.

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    11

    Note that large parts of the three routes are within areas mapped as terrestrial Critical Biodiversity

    Areas (Figure 2). The areas are designated terrestrial CBAs for various reasons, including the

    ecological connectivity that they provide between existing conservation areas (all of which are

    known to support many rare and localised plant species), the ecological connectivity that they

    provide between other CBAs, the known occurrence of many rare and localised plant species,

    and the presence of irreplaceable examples of sensitive habitat (such as quartz patches, quartz

    ridges, and shale and limestone outcrops) (Helme, 2013).

    Ecological Support Areas (ESA) is supporting zones or areas which must be safeguarded in order

    to prevent degradation of Critical Biodiversity Areas (CBA) and formal Protected Areas. In

    Ecological Support Areas, the ecological processes need to be maintained while in Protected

    Areas and Critical Biodiversity Areas, both pattern and process need to be safeguarded against

    degradation (Maree & Vromans, 2010).

    All three proposed Helios-Juno powerline corridors will traverse ESAs and CBAs, albeit in varying

    degrees (Figure 2). Juno substation is situated in a large CBA area, traversed by all three

    corridors. The CBA is associated with the Knersvlakte Hantam protected areas expansion focus

    area. In the vicinity of the Helios substation, all three corridors traverse an ESA associated with

    the Krom River, while further south, another ESA and CBA are associated with the

    Bokkeveldberge (mountain) and Krom Rivier. Corridor 3 aligns the most in this ESA.

    The Biodiversity Sector plan recommended biodiversity compatible land and resource use

    guidelines (Maree & Vromans, 2010). Within these guidelines, infrastructure development such

    as the proposed powerline, are restricted, indicating the powerline construction is possible under

    strict controls only in order to avoid impacts on biodiversity (Maree & Vromans, 2010).

    2.6 Succulent Karoo Ecosystem Programme (SKEP)

    The Succulent Karoo Ecosystem Programme (SKEP) is a long term, multi-stakeholder bioregional

    conservation and development programme with the aim of defining a way to conserve this

    Succulent Karoo ecosystem, and to develop conservation as land-use. The Succulent Karoo

    ecosystem is one of the Western Cape’s three biodiversity hotspots (a biogeographic region with

    a significant reservoir of biodiversity that is under threat from human activities).

    The Succulent Karoo biodiversity hotspot covers 116 000 square kilometers of desert

    (SKEP, 2013) and extends from the southwest through the northwestern areas of South Africa

    and into southern Namibia. The Succulent Karoo was the first only arid region to be recognised

    as a Biodiversity Hotspot and is home to over 6000 plant species, of which 40 percent are

    endemic, found nowhere else on earth. Succulents account for 29% of all plant species, as the

    region supports the richest succulent flora on earth (SKEP, 2013). Within the landscape, the

    heuweltjies (raised mounds of calcium-rich soil) support distinct plant communities. Despite its

    importance, less than 3.4 percent of the region existed in formal protected areas.

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    12

    In order to protect the Succulent Karoo, nine (9) geographic priority areas were identified as the

    most efficient locations for achieving the conservation targets of SKEP. These geographic priority

    areas were refined on the basis of their ability to contribute to the maintenance of Red Data List

    species, and maintain important ecological processes, particularly in the face of climate change

    (SKEP, 2013). In these priority areas, SKEP will seek to establish informal conservation networks

    that will achieve vegetation and process targets.

    One of the SKEP priority areas, the Knersvlakte, is situated within all three of the proposed

    corridors (Figure 3). This priority area has the greatest percentage of threatened endemics with

    128 species being listed. Threats to these species survival is largely due to small-scale mining for

    gypsum, diamonds and limestone/marble, overgrazing and the illegal harvesting of rare and

    spectacular species for national and foreign plant collections (SKEP, 2013). The SKEP

    partnership is coordinated through the South African National Biodiversity Institute (SANBI) and

    CapeNature and they should be consulted with regards to the proposed powerline corridors and

    preferred route.

    Figure 3: Planning domain of SKEP indicating the Knersvlakte and Moedverloren (Knersvlakte) Nature reserve (http://bgis.sanbi.org/skep/project.asp)

    http://bgis.sanbi.org/skep/project.asp

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    13

    The Knersvlakte has been identified by SKEP (Succulent Karoo Ecosystem Project; Driver et al

    2003) and numerous other studies (Hilton Taylor 1994, Desmet et al 1999, Van Wyk and Smith

    2001, etc.) as an area of exceptional botanical importance at the national and international level,

    with extraordinarily high numbers of endemic and localised plant species, making it one of the

    two richest areas for succulent plants in the world (along with the Richtersveld) (Helme, 2013).

    2.7 Expected Vegetation and Related Conservation Status

    2.7.1 Biomes

    The study area falls within two biomes: the Nama-Karoo Biome and the Succulent Karoo Biome

    of South Africa. The Helios substation and approximately the last 70km of the corridors before it

    reached Helios substation, is situated in the Nama-Karoo Biome which comprises an arid-to semi-

    arid region characterized by summer rainfall that varies between 100 and 520mm per year. The

    majority of this Biome is covered by a lime-rich, weakly developed soil over rock and although

    less than 5% of rain reaches the rivers, the high erodibility of soils poses a major problem where

    overgrazing and other disturbances that impact on the natural vegetation occurs (Mucina and

    Rutherford, 2006). The dominant vegetation is a grassy, dwarf shrubland wherein grasses tend

    to be more common in depressions and grazing rapidly increases the relative abundance of

    shrubs. This Biome is subjected to alien invasive species such as Opuntia aurantiaca (Prickly

    Pear) and Prosopis glandulosa (Honey-Mesquite). Most of the land is used for grazing and under

    conditions of overgrazing, some indigenous species may proliferate and even result in bush

    encroachment e.g. Rhigozum trichotomum (Three-thorn), Chrysocoma ciliata (Bitterbos) and

    Acacia karroo (Sweet Thorn). The Nama-Karoo has a relatively low floristic diversity (Mucina &

    Rutherford, 2006) and a limited number of rare or threatened plant species are expected to occur.

    The Nama-Karoo comprises a complex of plains dominated by low shrubs, mixed with grasses,

    succulents, geophytes (e.g. bulbs) and annual forbs (Mucina & Rutherford, 2006). Indigenous

    trees are mostly restricted to drainage lines or rocky outcrops.

    The Juno substation and the majority of the extent of the corridors are situated in the Succulent

    Karoo Biome which is a semi-desert region and is situated in a winter rainfall region. The area

    includes a high biodiversity. There is little difference between the soils of the Succulent Karoo and

    Nama Karoo Biomes - both are lime-rich, weakly developed soils on rock. The vegetation is

    dominated by dwarf, succulent shrubs, of which the Vygies (Mesembryanthemaceae) and

    Stonecrops (Crassulaceae) are particularly prominent. Mass flowering displays of annuals (mainly

    Daisies from the Asteraceae family) occur in spring, often on degraded or fallow lands. Grasses

    are rare, except in some sandy areas, while the number of plant species, mostly succulents, is

    very high and unparalleled elsewhere in the world for an arid area of this size (Mucina and

    Rutherford, 2006). Raised mounds of calcium-rich soil, thought to have been created by termites,

    often support distinctive plant communities. The area has little agricultural potential due to the

    lack of water and the lack of grasses limits grazing. Less than 0.5% of the area of the Succulent

    Karoo Biome has been formally conserved. The biome has a high number of plants of

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    14

    conservation concern. The high species richness and unique global status of the biome require

    urgent conservation attention.

    2.7.2 Broad-scale Vegetation Types (National Vegetation Map)

    A biome is made up of various vegetation types, based largely on soil, topography and climate

    variations within the biomes. The proposed powerline corridors could impact on fifteen (15)

    vegetation types as geographically presented in Figure 4 and listed in Table 1 below (Mucina &

    Rutherford, 2006). One of these vegetation types, Vanrhynsdorp Gannabosveld, is considered to

    be Vulnerable and is traversed by Corridor 2 & 3. None of this vegetation type is currently

    conserved and cultivation and open cast gypsum mining is posing a risk to this vegetation type.

    Most of the vegetation types along the propose powerline routes are not considered to be in

    danger as the remaining extent of natural vegetation (> 90%) is more than the conservation target

    (between 21% and 24%) for these vegetation unit. Although much of the vegetation occurring

    along the proposed powerline routes are classified as Least Threatened, very little or none of

    these vegetation types are formally protected e.g. in. reserves or other protected areas (Table 1).

    Although the Namaqualand Arid Grassland and Bokkeveld Sandstone Fynbos is not directly

    affected by the proposed routes, any deviation from the route as assessed here, may result in an

    impact and therefore they are listed here (Table 1).

    While the vegetation types occur over large areas and are classified as least threatened,

    cognisance must be taken of the extremely localised distribution of threatened species within

    these vegetation types. It follows that specific species might only be present in one locality within

    the larger vegetation type, making it extremely vulnerable to impacts.

    2.8 Listed Ecosystems

    The South African Biodiversity Act (Act 10 of 2004) provides for the listing of threatened or

    protected ecosystems. These ecosystems are grouped into Critically Endangered-, Endangered-

    , Vulnerable- and Protected Ecosystems (Section 52(1) (a) of the National Environmental

    Management: Biodiversity Act (Government Gazette 34809, Government Notice 1002, 9

    December 2011)). Development a listed ecosystem could have environmental authorization

    implications in terms of the National Environmental Management Act, 1998 (Act No 107 of 1998)

    [NEMA] and Environmental Impact Assessment (EIA) regulations.

    The Bokkeveld Sandstone Fynbos is listed as a Vulnerable ecosystem due to a high number of

    threatened plant species that occur within this system. Although no corridor as given in this report

    traverse through this ecosystem, Corridor 3 is in close proximity to this listed ecosystem.

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    15

    Table 1: Vegetation types that occur within the study area

    Biome

    Bioregion

    (vegetation organisation

    level between that of

    vegetation type and

    biome)

    Vegetation Type Conservation Status

    Nama-

    Karoo Bushmanland Bioregion Bushmanland Basin Shrubland

    Least Threatened but hardly

    protected

    Succulent

    Karoo

    Trans-Escarpment

    Succulent Karoo

    Hantam Karoo Least Threatened but hardly

    protected

    Western Bushmanland Klipveld Least Threatened but no formal

    protection in reserves etc

    Knersvlakte

    Northern Knersvlakte Vygieved Least Threatened but no formal

    protection

    Knersvlakte Shale Vygieveld Least Threatened but no formal

    protection

    Central Knersvlakte Vygieveld Least Threatened but no formal

    protection

    Knersvlakte Quartz Vygieveld Least Threatened but poorly

    protected

    Vanrhynsdorp Gannabosveld Vulnerable

    Namaqualand Hardveld

    Namaqualand Klipkoppe

    Shrubland

    Least Threatened but poorly

    protected

    Kamiesberg Mountains

    Shrubland

    Least Threatened but poorly

    protected

    Namaqualand Sandveld

    Namaqualand Spinescent

    Grassland

    Least Threatened but poorly

    protected

    Namaqualand Arid Grassland# Least Threatened, moderately

    protected

    Azonal*

    Inland Saline Vegetation Namaqualand Salt Pans

    (Inland saline vegetation)

    Least Threatened, no formal

    protection

    Namaqualand Riviere Least Threatened but hardly

    protected

    Fynbos Northwest Fynbos Bokkeveld Sandstone Fynbos# Least Threatened but hardly

    protected

    *water-logged and salt-laden habitats, the vegetation thus deviates from the typical surrounding zonal

    vegetation

    # situated just west / north from the proposed corridors, unlikely to be affected but possibility cannot be

    ruled out as route is not finalised yet

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    16

    Figure 4: Vegetation types present along the proposed Helios-Juno route corridors

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    17

    3. RESULTS OF THE FIELD ASSESSMENT

    Due to the corridors extending over two biomes, the vegetation observed in the southern extent

    of the corridors (including Juno substation and surrounds as well as the Knersvlakte) varied from

    the vegetation observed in the northern extent of the corridors, around the Helios substation. The

    southern extent is situated within the Succulent Karoo Biome and were characterised by dwarf to

    low shrubland with a high frequency of succulent plants, especially vygies and crassulas. The

    succulents, of which many belong to the Vygie-family (Mesembryanthemaceae) are referred to

    as Vygieveld and were grouped within the Succulent Karoo vegetation groups. Towards the

    Helios substation which is situated in the Nama-Karoo Biome, the plains comprised a mixture of

    arid grassland and dwarf shrubveld. This mixed vegetation covers most of the Great Karoo and

    comprises a mixture of Karoo bossies (dwarf shrubs

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    18

    Table 2: Vegetation groupings observed compared to the National Vegetation Map (Mucina & Rutherford, 2006)

    Vegetation grouping based on the field assessment

    Succulent

    Karoo Gannabos

    Mixed

    Karoo

    Vegetation

    on hills

    Salt pans

    vegetation Riparian

    Ve

    ge

    tatio

    n typ

    e a

    s p

    er

    Mu

    cin

    a &

    Ru

    therf

    ord

    (2

    006

    )

    Knersvlakte Shale

    Vygieveld X

    Northern Knersvlakte

    Vygieveld X

    Central Knersvlakte

    Vygieveld X

    Knersvlakte Quartz

    Vygieveld X

    Vanrhynsdorp

    Gannabosveld X

    Bushmanland Basin

    Shrubland X

    Namaqualand Spinescent

    Grassland X

    Hantam Karoo X

    Western Bushmanland

    Klipveld X

    Namaqualand Klipkoppe

    Shrubland

    X

    Kamiesberg Mountains

    Shrubland

    X

    Namaqualand Salt Pans

    (Inland saline vegetation)

    X

    Namaqualand Riviere

    X

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    19

    3.1 Broad Vegetation Groupings

    The bulk of the vegetation along the proposed powerline corridors was observed to be in a mostly

    natural state and was grouped as follows:

    1. Succulent Karoo;

    2. Gannabos vegetation;

    3. Mixed-Karoo vegetation (mainly around Helios substation);

    4. Vegetation on hills (rocky outcrops and ridges);

    5. Riparian vegetation (perennial and non-perennial); and

    6. Salt pans and associated vegetation.

    The vegetation groupings are discussed below and geographically represented in Figure 5.

    3.1.1 Succulent Karoo

    Land cover and land use

    The area is largely used for grazing. Vineyards were noted around Vredendal and the Olifants

    River Valley. Tourism, and in specific eco-tourism in the Knersvlakte is increasing. Conservation

    is now the primary land use in at least 25% of the Knersvlakte, and is rapidly replacing sheep

    farming as the primary land use throughout the region (Helme, 2013).

    Vegetation

    The southern extent of the corridors is situated within the Succulent Karoo vegetation group and

    were characterised by dwarf to low shrubland with a high frequency of succulent plants, especially

    vygies and crassulas. The succulents, of which many belong to the Vygie-family

    (Mesembryanthemaceae), are commonly referred to as Vygieveld.

    The vegetation is dominated by leaf succulents and some shrubs spread amongst the succulents.

    The grass layer is limited as well as tall shrubs and trees. The dominant vegetation displayed is

    mainly members of the Mesembryanthemaceae. Argyroderma species (dwarf compact plants

    resembling pebbles) as well as Crassula- and Aloe species are widespread in this vegetation

    group. Within the Vygieveld, varied habitats occur, which lead to another subdivision of the

    Vygieveld group into Quartz Vygieveld, Shale Vygieveld and Northern & Central Vygieveld:

    The Quartz Vygieveld is observed on undulating to flat landscapes covered by prominent and

    patchy layers of quartzite or on rocky ridges and slopes (Mucina and Rutherford, 2006; Helme,

    2013). Much of the terrain is covered with quartz gravel which provide habitat to unique dwarf

    succulents that are found nowhere else. The white quartz gravel reflects the sunlight, and is not

    as hot as the darker rocks and soil. Many of the succulents here are usually dwarf and compact -

    ideal to absorb thermal heat in the short cool winter growing season when rain occurs (SANBI,

    2012). Furthermore, the white quartz is likely at least three or four degrees cooler at ground level

    than soil without quartz pebbles, and that this is one of many reasons for the diversity of plants in

    this habitat (Schmiedel & Jurgens, 1999 In Helme, 2013). In these areas, succulents such as

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    20

    Figure 5: Broad vegetation groupings within the proposed Helios-Juno corridors

    1E

    1F

    1G

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    21

    the vygies are often well camouflaged and are sometimes referred to as ‘living stones’

    (Photograph 2). As stated by Helme (2013), although the vegetation itself often looks sparse and

    depauperate it is actually extremely rich in localised endemics, notably dwarf succulents

    (Photograph 2). Many of these are cryptic and hard to see, and all are very vulnerable to

    disturbance of any type, notably trampling, being squashed by vehicles, and disturbance of their

    quartz pebble habitat. This is the most sensitive habitat in the studied area (Helme, 2013). As per

    Mucina and Rutherford (2006): “The mosaic of floristically and ecologically distinct quartz

    vygieveld communities and the matrix of low succulent shrublands, with Rushia and

    Drosanthemum as the most prominent structure-determining genera, are very intricate and small

    scale in places”.

    Photograph 2: Quartz Vygieveld with Argyroderma and Crassula species

    Crassula columnaris

    subsp prolifera

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    22

    At least seventy dwarf succulent and geophyte plant species are known to be endemic (restricted)

    to this vegetation type (Mucina & Rutherford 2006), an astonishingly high level of endemism for

    a localised, arid vegetation type (Helme, 2013). Common species in the Quartz Vygieveld include:

    Didelta spinosa, Drosanthemum diversifolium, Ruschia species, Salsola species and geophetic

    herbs such as Oxalis species and Drimia intricata. Small succulents include Crassula species,

    Tetragonia echinata, and Mesembryanthemum species.

    Shale Vygieveld occurs on silty or shale derived soils in the region on level plains, hilltops and

    moderate to steep slopes (Mucina & Rutherford, 2006). The vegetation comprises shrubland with

    low cover of mat forming shrubs, mainly with succulent leaves and spiny shrubs. Common and

    dominant succulent shrub species include Asparagus capensis (Wag-‘n-bietjie), Augea capensis

    (Boesmandruiwe), Lampranthus uniflorus and Ruschia spinosa. A number of shrubs also occur

    including Eriocephalus eriocoides (Kappokbos), Atrilex vestita (Soutbos) and Galenia fructicosa.

    Succulent herbs noted include Brownlanthus species, Phyllobolus species and Tetragonia

    species. In addition, Brunsvigia cf bosmania was in flower and observed within Corridor 1,

    although likely occurring in all three corridors (Photograph 3). One endemic and Critically Rare

    species, Tyleocodon suffulutus is restricted to this Vygieveld

    Photograph 3: Brunsvigia within Corridor 1 – note existing powerline in the background - arrow

    Northern and Central Vygieveld combines vegetation types that are predominantly succulent with

    shrubs, as well as where the grass layer is more abundant (Photograph 4). It also includes

    vegetation that occurs only where the limestone (dolomite) is accessible at or very close to the

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    23

    soil surface (Helme, 2013). The vegetation on dolomite comprises less than 10% of the

    Knersvlakte but due to dolomite mining, species occurring here would rapidly become threatened

    (Helme, 2013). At least 14 plant species are thought to be restricted to this habitat, including

    Bulbine margarethae, Oxalis sp. nov., Conophytum uviforme ssp. subincanum (thought to be

    endemic to Wolwenes), Ixia acaulis, Babiana carminea, Moraea deserticola, Antimima dualis, A.

    turneriana, A. evoluta, A. fenestrata, Brunsvigia radula, Colchicum albofenestratum (ined.),

    Eriospermum calcareum and Eriospermum arachnoideum (Helme, 2013).

    Photograph 4: (Northern) Vygieveld in Corridor 3

    Images from Hemle (2013) indicate how the Vygieveld transforms after rainfall (Photograph 5).

    The Vygieveld is the most widespread along the corridors and as this vegetation group include a

    number of endemic and scarce species, the final route alignment will have to take cognisance of

    these. Within the Vygieveld, the invasive alien shrub Atriplex lindleyi subsp. inflata (Blasiebrak) is

    common in disturbed parts, especially where quartz fields have been disturbed.

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    24

    Photograph 5: Vygieveld during the dry summer (top) and after good winter rains (bottom)

    (pictures from Helme, 2013)

    3.1.2 Gannabos

    Land cover and land use

    Within the Knersvlakte, the Vanrhynsdorp Gannabosveld support succulent shrubland that is

    dominated by Salsola species. Salsola plants are commonly referred to as saltwort or Gannabos,

    due to their ability to tolerate high salt conditions in soils. The Gannabos is found on silty soils,

    and has already lost at least 21% of its original total regional extent (mostly to gypsum mining and

    agriculture), and is consequently listed as a Vulnerable vegetation type (Rouget et al 2004 In

    Helme, 2013) (Mucina & Rutherford, 2006).

  • Oct 2013

    Updated July 2015

    Helios-Juno Powerline: Vegetation Assessment

    25

    Vegetation

    Except for the Salsola species, Ruschia and Drosanthemum species are also abundant. Other

    than succulent shrubs and herbs such as Phyllobolus nitidus, Psilocaulon junceum (Asbos) and

    Euphorbia mauritanica, geophetic herbs as well as grasses such as Bromus pectinatus (Japanese

    brome), Enneapogon desvauxii (Eight Day Grass) and Stripagrostis ciliata also occur. A number

    of endemic species (species restricted to this vegetation type) occur here including Eriospermum

    eriophorum which is a Critically Endangered species, as well as the Vulnerable specie Euphorbia

    fasciculata, Cotula pedunculata and Brownanthus glareicola.

    3.1.3 Mixed-Karoo vegetation

    Land cover and land use

    The land cover comprised mainly of natural vegetation utilised for grazing. Solar plants and wind

    farms are proposed to be implemented around Helios substation. Eskom is also constructing a

    wind farm in Vredendal (Sere Wind Farm). Disturbances were limited to localised erosion or

    infrastructure development and other than overgrazing in some areas, the vegetation was

    relatively intact.

    Vegetation

    The Mixed-Karoo term comprised the grouping of vegetation that is predominantly arid grassland

    and vegetation that is predominantly dwarf shrubveld (e.g. around Helios substation) or succulent

    shrubland (e.g. around Juno substation). In addition, the grouping also includes areas where

    succulent shrubs and microphyllous karroid shrubs are dominant (e.g. Hantam Karoo).

    Around the Juno substation, the vegetation contained a higher grass frequency than other sample

    areas in the Knersvlakte. The soils here was noticeable deeper with a low stone content (Mucina

    & Rutherford, 2006). The grass layer was dominated by the spinescent Cladoraphis spinosa

    (Spiny Love Grass), while shrubs were succulent and non-succulent (Photograph 6).