Helios-Juno Powerline: Vegetation Assessment · Helios-Juno Powerline: Vegetation Assessment iii...
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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
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.
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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
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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
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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
(
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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.
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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.
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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.
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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
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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
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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
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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
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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;
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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
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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).
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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
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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.
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Figure 1: Locality of the proposed corridor alternatives
Corridor 1
Corridor 2
Corridor 3 Deviation 1E
Deviation 1F
Deviation 1G
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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.
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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.“
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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
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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.
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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.
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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
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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
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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.
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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
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Figure 4: Vegetation types present along the proposed Helios-Juno route corridors
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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
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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
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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
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Figure 5: Broad vegetation groupings within the proposed Helios-Juno corridors
1E
1F
1G
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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
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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
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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.
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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).
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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).