botanical assessment of the proposed clifton precinct ......proposed clifton precinct for city of...

T · +27 21 702 2884 26 Bell Close, Westlake Business Park F · +27 86 555 0693 Westlake 7945, Cape Town NCC Environmental Services (Pty) Ltd | Reg No: 2007/023691/07 | VAT No. 4450208915

REAL GROWTH FOR PEOPLE, PLANET AND BUSINESS www.ncc-group.co.za

PREPARED FOR:

Neil D. Eybers, Property Management Department, City of Cape Town

DATED:

17 June 2015

PREPARED BY:

Robin Jangle

M · 073 483 5504

E · [email protected]

Botanical Assessment of the

proposed Clifton Precinct Project,

Cape Town, Western Cape

Province

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NCC Environmental Services (Pty) Ltd Botanical Assessment: Proposed Clifton Precinct – Jun 2015 of 27 Reg No: 2007/023691/07

DECLARATION OF INDEPENDENCE

I, Robin Jangle as duly authorised representative of NCC Environmental Services (Pty) Ltd (NCC), hereby

confirm my independence (as well as that of NCC) as a specialist and declare that neither I nor NCC have any

interest, be it business, financial, personal or other, in any proposed activity, application or appeal, other

than fair remuneration for worked performed, specifically in connection with the Botanical Assessment for

Proposed Clifton Precinct for City of Cape Town. I further declare that I am confident in the results of the

studies undertaken and conclusions drawn as a result of it – as is described in my attached report.

Signed:

Robin Jangle

17 June 2015

Biodiversity Specialist – NCC Environmental Services (Pty) Ltd.

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DECLARATION OF INDEPENDENCE

I, Karien Potgieter, as duly authorised representative of NCC Environmental Services (Pty) Ltd. (NCC), hereby

confirm my independence (as well as that of NCC) as a specialist and declare that neither I nor NCC have any

interest, be it business, financial, personal or other, in any proposed activity, application or appeal, other

than fair remuneration for worked performed, specifically in connection with the Botanical Assessment for

Proposed Clifton Precinct for City of Cape Town. I further declare that I am confident in the results of the

studies undertaken and conclusions drawn as a result of it – as is described in the attached report.

Signed:

Karien Potgieter

17 June 2015

Senior Conservation Technician – NCC Environmental Services (Pty) Ltd.

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TABLE OF CONTENTS

1 INTRODUCTION ................................................................................................................ 5

2 SERVICE SCOPE ................................................................................................................. 5

3 ASSUMPTIONS AND LIMITATIONS ..................................................................................... 6

4 ALTERNATIVES .................................................................................................................. 7

5 ASSESSMENT METHODOLOGY ........................................................................................... 7

6 DESCRIPTION OF AFFECTED ENVIRONMENT ...................................................................... 8

6.1 BROAD SITE DESCRIPTION ....................................................................................................................8

6.2 ECOSYSTEM AND COMMUNITY LEVEL .................................................................................................8

6.3 REGIONAL CONTEXT OF VEGETATION ............................................................................................... 12

7 ASSESSMENT OF IMPACTS............................................................................................... 13

7.1 CONSTRUCTION ................................................................................................................................. 13

7.2 OPERATIONS ...................................................................................................................................... 17

8 MITIGATION MEASURES ................................................................................................. 18

8.1 CONSTRUCTION ................................................................................................................................. 18

8.2 OPERATIONS ...................................................................................................................................... 19

9 CONCLUSION AND RECOMMENDATIONS ........................................................................ 20

10 REFERENCES.................................................................................................................... 21

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1 INTRODUCTION

NCC Environmental Services (Pty) Ltd. (NCC) was appointed by City of Cape Town (the Client) to conduct a

botanical assessment of the proposed Clifton Precinct development on Cape Town’s Atlantic seaboard.

2 SERVICE SCOPE

The Terms of Reference are as per QUOTATION NUMBER: R031500910 (DESCRIPTION: The provision of

consulting services on the completion of a site specific Botanical Survey for the Proposed Clifton Precinct

Project):

“Based on the fact that this is a highly sensitive area from a heritage, environmental, and scenic drive point

of view it is intended that a level of detail that satisfies the desire to test the feasibility of aspects of the

development be achieved (study area indicated in Annexure A).

1. Produce a baseline analysis of the botanical attributes of the study area. 2. This report should clearly indicate any constraints that would need to be taken into account in

considering any development proposals further. 3. The baseline report must include a map of the identified sensitive areas as well as indications of

important botanical constraints. It must also: a. Describe the broad ecological characteristics of the site and its surrounds in terms of any

mapped spatial components of ecological processes and/or patchiness, patch size, relative isolation of patches, connectivity, corridors, disturbance regimes, ecotones, buffering, viability, etc.

In terms of biodiversity pattern, identify or describe:

Community and ecosystem level

a. The main vegetation type, its aerial extent and interaction with neighbouring types, soils or

topography;

b. The types of plant communities that occur in the vicinity of the site

c. Threatened or vulnerable ecosystems (cf. SA vegetation map/National Spatial Biodiversity

Assessment, etc.)

Species level

d. Plant Species of Conservation Concern (SCC; give coordinates if possible)

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e. The viability of and estimated population size of the SCC that are present (include the degree

of confidence in prediction based on availability of information and specialist knowledge, i.e.

High=70-100% confident, Medium 40-70% confident, low 0-40% confident)

f. The likelihood of other SCC occurring in the vicinity (include degree of confidence).

Other pattern issues

g. Any significant landscape features or rare or important vegetation associations such as

seasonal wetlands, alluvium, seeps, quartz patches or salt marshes in the vicinity.

h. The extent of alien plant cover of the site, and whether the infestation is the result of prior

soil disturbance such as ploughing or quarrying (alien cover resulting from disturbance is

generally more difficult to restore than infestation of undisturbed sites).

i. The condition of the site in terms of current or previous land uses.

In terms of biodiversity process, identify or describe:

j. The key ecological “drivers” of ecosystems on the site and in the vicinity, such as fire.

k. Any mapped spatial component of an ecological process that may occur at the site or in its

vicinity (i.e. corridors such as watercourses, upland-lowland gradients, migration routes,

coastal linkages or inland-trending dunes, and vegetation boundaries such as edaphic

interfaces, upland-lowland interfaces or biome boundaries).

l. Any possible changes in key processes, e.g. increased fire frequency or drainage/artificial

recharge of aquatic systems.

4. What is the significance of the potential impact of the proposed project – with and without

mitigation – on biodiversity pattern and process at the site and regional scale?

5. Recommend actions that should be taken to prevent or mitigate impacts.

Indicate how these should be scheduled to ensure long-term protection, management and

restoration of affected ecosystems and biodiversity.

6. Indicate limitations and assumptions, particularly in relation to seasonality.

3 ASSUMPTIONS AND LIMITATIONS

In the absence of a geo-referenced site layout, a non-referenced diagram had to be produced by an

NCC GIS technician. The accuracy of the overlay is questionable, however the potential impacts could

still be inferred.

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It is assumed that the pedestrian routes will be constructed of concrete or similar impervious material.

The site assessment was conducted during late autumn, which is generally accepted as an unsuitable

season for accurately identifying flora. The main flowering time period in the Fynbos Biome is

September-October. We are, however, confident that no flora of conservation concern (“Red List”

plants) occurs on the site.

4 ALTERNATIVES

Alternative 1: No Go

The majority of the proposed Clifton Precinct is an entirely transformed landscape of no conservation value.

There are, however, patches of Regionally significant vegetation (Cape Flats Dune Strandveld: Endangered)

below the transformed area. There are Significant impacts associated with the development in its proposed

layout to these patches resulting in residual impact.

Clifton Precinct in its proposed layout will have Significant residual impact to the natural vegetation patches

and is rated as a No-Go.

Alternative 2: Re-designed layout to avoid destruction of existing natural vegetation

The layout must be re-designed to avoid the patches of Cape Flats Dune Strandveld, as well as the Cape

Lowlands Freshwater Wetlands. This will Avoid the impacts associated with the development in its presently

proposed layout.

5 ASSESSMENT METHODOLOGY

A desktop study of the receiving environment was conducted to inform the site visit. Resources consulted

include: VegMap (2006), SANBI BGIS (City of Cape Town BioNet) and SANBI TSP: CREW data (consolidated

voucher records incorporating PRECIS).

A site assessment was conducted on 22 May 2015. The site was systematically traversed and the taxa and

assemblages were noted. The proposed route and construction methods were assessed against the

receiving environment’s sensitivity.

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6 DESCRIPTION OF AFFECTED ENVIRONMENT

6.1 BROAD SITE DESCRIPTION

The proposed Clifton Precinct is situated on the Glen Country Club and Maiden’s Cove. It is bounded to the

east by Victoria Road, to the south by Glen Beach to the west by the Atlantic Ocean and to the north by

Clifton Fourth Beach.

The natural area between Victoria Road and Lower Kloof Road has been assigned the status of Critical

Biodiversity Area (CBA) 2 in City of Cape Town’s BioNet. This area forms a buffer to the CBA 1 above Kloof

Road.

For the most part the site is transformed (sports fields, parking areas and lawns), however there are patches

of natural vegetation below the transformed areas down to the strandline. Refer to Appendix 1 (Figure 1).

6.2 ECOSYSTEM AND COMMUNITY LEVEL

The natural vegetation remnants on site are: FS 6 Cape Flats Dune Strandveld (Endangered, Anon., 2009),

AZd 3 Cape Seashore Vegetation, AZf 1 Cape Lowlands Freshwater Wetlands and FOz 6 Southern Coastal

Forest (sub-type: Western Milkwood Forest) (Mucina & Rutherford, 2006). Refer to Appendix 1 (Figure 2).

The Cape Flats Dune Strandveld (CFDS) is of particular significance. It occurs as two structurally distinct

patches on site. The northern patch (“1” in Figure 2) is situated immediately below and around the

bungalows at Clifton Fourth Beach and the southern patch (“2” in Figure 2) ranges from the southern parking

area to Glen Beach.

The northern patch is a low to mid-high, mid-dense to closed shrubland. The structural complexity is in

response to substrate depth (=water retention) as well as the height of the granite boulders (degree of

shelter provided). The vegetation is lowest closest to the sea where the granite is weathered (plants are

exposed to shearing salt-laden wind) and the soil is shallower. Conversely the tall shrubland is in deeper soil

with large sheltering boulders, furthest from the sea. Refer to Appendix 2: Figures 3 and 4.

The lower portion of this patch (below the granite batholith trending on a north-south axis to the west of Erf

491) is remarkable in that despite its very limited spatial extent, the floristic diversity is comparable (as an

equal-sized patch) to some of the larger continuous expanses, such as those along False Bay. The upper

portion of the CFDS patch, immediately south of Erf 491 (visible as a cultivated lawn) up to the north-west

corner of the tennis courts and along the western boundary of the tennis courts, has been severely disturbed

and in places transformed. This is due to access paths braiding and trampling the vegetation as well as

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transformation of the vegetation as private garden space. This strip has a lower conservation value than the

remainder of the CFDS in the northern patch.

Taxa noted:

Shrubs: Searsia glauca, S. laevigata, Euclea racemosa, Olea exasperata, Osteospermum monilifera, O.

incana, Salvia africana-aurea, Metalasia muricata, Asparagus capensis, Phylica ericoides, Eriocephalus

africanus, Helichrysum revolutum, Pelargonium capitatum, Linum africanum

Succulent shrubs: Cotyledon orbiculata, Carpobrotus acinaciformis, Tetragonia spicata, Ruschia macowanii,

Drosanthemum scandens

Graminoids: Ehrharta villosa, Sporobolus virginicus, Scirpoides nodosus

Herbs: Gazania maritima, Senecio elegans

Geophytic herbs: Satyrium c.f. odorum, Oxalis ecklonii, Trachyandra ciliata, Ornithogalum thyrsoides, Albuca

juncifolia, Ferraria crispa, Empodium plicatum, Spiloxene ovata.

This patch of CFDS grades into Cape Lowlands Freshwater Wetlands to the south and Cape Seashore

Vegetation to the west (high water mark).

The general inaccessibility of this patch has enabled its persistence. Trampling of, in particular the lower-

growing communities, as well as those in pockets on the rock, would result in the destruction thereof.

Of further concern is the high number of exotic taxa in this patch. These no doubt arise from the gardens of

the bungalows at Clifton Fourth. It would also appear as though some have been deliberately planted.

These exotics and Invasive Alien Plants (IAPs) have a negative impact on the ecosystem through affecting

nutrient cycling as well as competition for resources (space, nutrients, pollination and seed dispersal).

Exotic flora and IAPs noted:

Acacia cyclops (Declared Invader: Conservation of Agricultural Resources Act, 1983 (Act No. 43 of 1983)

(CARA) Category 2), Pennisetum setaceum (Declared Weed: CARA Category 1), Myoporum tenuifolium

(Declared Invader: CARA Category 3), Phoenix canariensis, Coprosma lucida, Pittosporum crassifolium, Yucca

aloifolia, Limonium perezii, Gypsophila c.f. paniculata, Aloe arborescens, A. thraskii (hybrids)

The southern patch is a dwarf to tall, mid-dense to closed shrubland. This patch also exhibits the increase in

height with distance from the sea. The slope rises steeply from the beach to the road above. Closest to the

beach the vegetation is a dwarf, mid-dense to closed shrubland. It gets progressively taller behind the

boulders and where the slope becomes steeper, resulting in a tall, closed shrubland. On more water

retentive, richer soils along the Atlantic seaboard this tall shrubland is generally a precursor of Southern

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Coastal Forest (SCF). The shrubland in the southern patch however does contain a significant asteraceous

component which could indicate that it is in a state and not in transition to SCF.

Taxa noted:

Shrubs: Lycium ferocissimum, Morella cordifolia, Searsia glauca, S. laevigata, S. lucida, Euclea racemosa,

Olea exasperata, O. europaea subsp. africana, Gymnosporia buxifolia, Osteospermum monilifera, O. incana,

Salvia africana-aurea, Metalasia muricata, Asparagus capensis, Phylica ericoides, Eriocephalus africanus,

Helichrysum revolutum, Pelargonium capitatum

Succulent shrubs: Carpobrotus acinaciformis, Tetragonia spicata, Ruschia macowanii

Graminoids: Ehrharta villosa, Sporobolus virginicus, Scirpoides nodosus

Herbs: Gazania maritime, Senecio elegans,

Geophytic herbs: Oxalis ecklonii, O. pes-caprae, Trachyandra ciliata, T. revoluta, Albuca juncifolia, Ferraria

crispa

The southern patch is only lightly infested with exotic flora and IAPs and is of high conservation value.


Acacia cyclops (Declared Invader: CARA Category 2), Myoporum tenuifolium (Declared Invader: CARA

Category 3), Coprosma lucida

The Cape Seahore Vegetation (CSV) occurs in the dynamic strandline. At Clifton Precinct it was encountered

immediately below the northern patch of CFDS in coarse substrate comprising gravel and seashells. It is

generally composed of opportunistic taxa that possess traits that enable them to survive the high incidence

of system disturbance e.g. surging tides and shifting substrate.

The CSV at Clifton Precinct is a dwarf, sparse to mid-dense shrubland comprising succulent mat-forming

shrubs.

Taxa noted:

Succulent shrubs: Drosanthemum scandens, Chenolea diffusa, Tetragonia decumbens

A single continuous patch of Cape Lowlands Freshwater Wetlands (CLFW) occurs below the sports fields –

from the tennis courts in the north to approximately midway along the lower boundary of the fields. Refer

to Appendix 2: Figures 5 and 6.

The vegetation is a low to mid-high, closed graminoid-shrubland. Both the structure and flora are typical of

a wetland embedded in CFDS in that they are not particularly species-rich or diverse in structure.

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The wetland is as a result of a basin formed by the granite batholith and is fed by both precipitation and up-

slope seepage. It would appear as though the up-slope seepage is negatively impacted by over-recharge

from both the sports fields and a garden that has extended beyond the boundaries of Erf 491. This has

resulted in the establishment of exotic and indigenous invasive flora such as Typha capensis and Pennisetum

clandestinum. Whilst T. capensis is indigenous, it most likely would not have occupied the spatial extent that

it does. The constant recharge has enabled T. capensis to colonise what would’ve been ecologically

unsuitable habitat for it i.e. shallow substrate that is completely dry during summer resulting in desiccation

of the rhizomes.

Taxa noted:

Megagraminoids: Typha capensis

Graminoids: Scirpoides nododus, Paspalum vaginatum

Shrubs: Senecio halimifolius, Plechostachys serpyllifolia

Although species-poor, the wetland contributes to the overall diversity of the natural space as it supports

fauna that would otherwise not be present such as amphibians and various avifauna. Furthermore the

wetland serves an important function in regulating the water flow to the surrounding CFDS. Any water-

obstructing structure through the wetland would result in upslope becoming overly wet to support CFDS

whereas downslope would become more xeric and result in a significant shift in the vegetation structure and

floristics.

Of concern is the high density of transforming exotic flora. Not only are these structurally altering the

vegetation, but also the functioning of the wetland. If the recharge was consistent with the precipitation the

exotic flora would still persist, albeit it reduced density.


Phoenix canariensis, Pennisetum clandestinum

The wetland is bordered to the north and west by CFDS and to the south by CSV.

A small patch of Southern Coastal Forest (SCF) is situated at the main entrance off Victoria Road. This patch

has been negatively impacted by rubble dumping, IAPs (in particular Acacia cyclops and Myoporum

tenuifolium), as well as cutting of the indigenous trees to improve security.

The vegetation comprises small trees (<5m tall) of Euclea racemosa, Gymnosporia buxifolia and Olea

europaea subsp. africana.

The patch is completely cut off from any other patches of natural vegetation by roads and parking areas.

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6.3 REGIONAL CONTEXT OF VEGETATION

The CFDS at Clifton Precinct represents the last remaining significant patch on the Atlantic seaboard

between Mouille Point and Noordhoek. North of Mouille Point the only remaining significant patch is

situated in Milnerton (Sunset Beach continuing to Melkbos). There is a small patch on Paarden Island,

although this is in a perturbed state, species depauperate and unlikely to persist without intensive

management intervention. To the south there are very compressed, depauperate patches at Llandudno.

These are compressed between the SCF and the actual beach and hardly comparable to the patches at

Clifton Precinct in terms of structural and floristic complexity. The only remaining significant patches on the

Atlantic seaboard are therefore from Noordhoek southwards to Cape Point. The patches at Clifton Precinct

however are unique. They differ from CFDS elsewhere in that the substrate is marine sand over Cape

Granite. This represents a unique ecosystem and these patches are therefore not only of Local but also

Regional significance and I would consider them irreplaceable. The CSV and CLFW are intrinsically connected

to the CFDS at the site and any further perturbance or impact to them is best avoided as it will result in

cascading effects on the CFDS. The patch of SCF is also of Local significance. Although structurally and

floristically compromised, it does represent the northern-most remnant of the vegetation type. To the south

of the proposed Clifton Precinct there are small patches of SCF along the coast with significant patches at

Llandudno and Noordhoek.

CFDS is listed as Endangered (EN) under Criterion D1 (Anon., 2009). Under Criterion D1 an ecosystem must

harbour 60-79 “threatened Red Data list plant species” to qualify for EN status (Anon., 2009). Whilst no flora

of conservation concern (“Red List” flora) were encountered on site, this does not detract from the

conservation value of the vegetation as noted under the description of each patch thereof. The uppermost

portion of Patch 1 (northern patch) is however severely disturbed and in parts transformed. It is of low

conservation value. Whilst considering that CFDS is listed as EN based on the number of species of

conservation concern and not remaining spatial extent, it stands to reason that patches thereof that are in a

poor state and of low conservation value can be considered for development. The impact hereof is rated

below.

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7 ASSESSMENT OF IMPACTS

7.1 CONSTRUCTION

Impact 1: Loss of Cape Flats Dune Strandveld (Endangered) (Southern Patch)

Table 1: Assessment of impact on ecosystem: Loss of Cape Flats Dune Strandveld (Southern Patch)

Nature Negative

Impact Source Construction of parking area on, and pedestrian routes through patches of Cape Flats Dune Strandveld resulting in nett loss.

Magnitude Extent Medium

Intensity High

Duration High

Potential for impact on irreplaceable resources

High

Consequence High

Significance Without Mitigation High H

With Mitigation High H

Probability High

Construction of pedestrian routes through the patches of CFDS would result in fragmentation with an

increase in edge effect and ultimately a reduction in structural and floristic complexity, thereby reducing its

regenerative capacity. Intensity is therefore rated as High due to the potential of impact to alter the

functioning of the ecosystem and result in a transformed state.

Extent is rated as Medium as the impact would affect the Local to Regional surroundings.

Given the Regional significance of these patches of CFDS, as well as their unique abiotic features, they are

considered irreplaceable (not possible to recreate) hence the Potential for impact on irreplaceable

resources is rated as High.

Significance With Mitigation is ranked as High because the impact cannot be mitigated due to the

compressed spatial extent of the ecosystem and the abiotic complexity.

Impact 2: Loss of Cape Flats Dune Strandveld (Endangered) (Northern Patch)

Table 3: Assessment of impact on ecosystem: Loss of Cape Flats Dune Strandveld (Northern Patch)

Nature Negative

Impact Source Construction of pedestrian walkway through patch of Cape Flats Dune Strandveld resulting in nett loss.


Intensity High

Duration High


High

Consequence High

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With Mitigation Low H

Probability High

Construction of pedestrian routes through the patches of CFDS would result in fragmentation with an

increase in edge effect and ultimately a reduction in structural and floristic complexity, thereby reducing its

regenerative capacity. Intensity is therefore rated as High due to the potential of impact to alter the

functioning of the ecosystem and result in a transformed state.

The impact can however be Mitigated. The Consequence would then be Low as a result of Intensity,

duration, extent and impact on irreplaceable resources all rated Low. This is because if the walkway is

constructed of wooden slats and pinned to the granite batholiths only, thereby avoiding all contact with the

vegetation (including shading) there won’t be an impact.

Impact 3: Loss of Cape Flats Dune Strandveld (Endangered) in poor condition (eastern limit of Northern

Patch)

Table 3: Assessment of impact on ecosystem: Loss of Cape Flats Dune Strandveld (Northern Patch)

Nature Negative

Impact Source Transformation of patch of poor condition Cape Flats Dune Strandveld (adjoining the tennis courts) resulting in nett loss.


Intensity Low

Duration High


Medium

Consequence Medium

Significance Without Mitigation Medium M

With Mitigation Medium M

Probability High

Transformation of the poor condition CFDS adjoining the tennis courts is rated as Medium for Potential for

impact on irreplaceable resources as the portion is species and structurally depauperate and can be

recreated by planting the floristic component. The Consequence is rated as Medium as a result of the

Medium rating for irreplaceable resources as well the low intensity. Intensity is rated as Low as a result of

the impact affecting the environment in such a way that natural functions and processes are minimally

affected. This is because the vegetation is in a poor state and is somewhat separated from the high

conservation value vegetation closer to the sea.

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Significance With Mitigation is rated as Medium because the mitigation recommended is Compensation. It

is rated as Medium because the mitigation will still not replace the resource. The impact of the

transformation (by development) can be managed by preventing alteration of the hydrology.

Impact 4: Loss of Cape Lowlands Freshwater Wetlands

Table 4: Assessment of impact on ecosystem: Loss of Cape Lowlands Freshwater Wetlands

Nature Negative

Impact Source Construction of pedestrian routes through Cape Lowlands Freshwater Wetlands


Intensity High

Duration High


High

Consequence High


With Mitigation Medium M

Probability High

Construction of pedestrian routes or any hard, obstructing structure through the CLFW would result in

altered hydrology. Wetland flora are obligate hydrophytes, only capable of persisting under hydrological

regimes that are within their range of tolerance. Obligate hydrophytes have a narrow range of tolerance and

this accounts for the specific flora found in the wetland occurring nowhere else in the landscape at Clifton

Precinct. Altered hydrology would result in transformation of the ecosystem. Intensity is therefore rated as

High due to the potential of impact to alter the functioning of the ecosystem and result in a transformed

state.


Given the Local significance of the wetland (reducing and slowing the seepage to the CFDS, thereby enabling

its persistence) as well as their unique biotic and abiotic features, they are considered irreplaceable (not

possible to recreate), hence the Potential for impact on irreplaceable resources is rated as High. It is

important to consider the wetland as an ecological support system for the more threatened CFDS. Altering

the hydrology will have cascading effects (cumulative impacts) on the Strandveld, resulting in

transformation. This aspect is therefore rated cumulatively with this support function in mind.

Significance With Mitigation is rated as Medium because the impact can be mitigated to an extent where

the hydrological function is not impeded, but the wetland flora could be somewhat altered. The Intensity

would then be Medium (with Mitigation) as the affected environment would be altered, but natural

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functions and processes can continue albeit in a modified way; and important, sensitive communities are

negatively affected. Mitigation is discussed further in “Mitigation Measures”.

Impact 5: Loss of Southern Coastal Forest

Table 5: Assessment of impact on ecosystem: Loss of Southern Coastal Forest

Nature Negative

Impact Source Destruction of WMF in development footprint

Magnitude Extent Low

Intensity Low

Duration High


Medium

Consequence Low

Significance Without Mitigation Low L

With Mitigation Low L

Probability High

Construction of Clifton Precinct in its proposed format will result in the destruction of a patch of SCF. The

patch is depauperate and has been severely impacted by management activities and IAPs. It is a remnant,

no longer contiguous with any other vegetation at Clifton Precinct.

Extent is rated as Low as it comprises a few small trees sandwiched between roads and buildings. The

impact is therefore Local (site-specific). Intensity is rated Low as the natural functions and processes are

minimally affected as the ecosystem is already mostly transformed. Potential for impact on irreplaceable

resources is rated as Medium, as the resources can be replaced with effort i.e. they can be replanted

elsewhere on site (in an ecologically suitable area) together with milkwood, Sideroxylon inerme to recreate a

patch of WMF.

Significance Without Mitigation is rated as Low, because the impact is limited to a very small area of already

mostly transformed ecosystem. Significance With Mitigation is rated as Low, because the ecosystem is

mostly transformed and does not contribute to the ecological integrity of the site.

It is a novelty and a nice-to-have, however and it can either be left intact and incorporated into the site

design and then augmented with milkwood trees (from elsewhere on the site) and managed as a feature.

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7.2 OPERATIONS

Impact 1: Alteration of hydrology resulting in transformation of ecosystems

Table 6: Assessment of impact on ecosystems: Alteration of hydrology

Nature Negative

Impact Source Alteration of hydrology (increased recharge) resulting in transformation of ecosystems.


Intensity High

Duration High


High

Consequence High


With Mitigation Low L

Probability High

The ecosystems (=vegetation units) at Clifton Precinct are as a result of complex interaction between the

physical environment and between the ecosystems themselves. The ecosystems are intrinsically linked to

one another, so much so that one cannot be viewed in isolation without considering the impacts to the

other. From a vegetation zonation perspective the CLFW at Clifton precinct is seen as being embedded in

the CFDS, thereby acknowledging the complex interaction between the two ecosystems. Although the

recharge of the wetland is seasonally dependent and varies from year to year, the ecosystems have been

shaped by this disturbance regime. Altering the hydrology would result in transformation of the ecosystems.

Intensity is therefore rated as High due to the potential of impact to alter the functioning of the ecosystem

and result in a transformed state.


Given the Regional significance of the CFDS, it is considered irreplaceable (not possible to recreate) hence

the Potential for impact on irreplaceable resources is rated as High. It is important to consider the wetland

as an ecological support system for the more threatened CFDS. Altering the hydrology will have cascading

effects (cumulative impacts) on the Strandveld resulting in transformation. This aspect is therefore rated

cumulatively with this support function in mind.

Significance With Mitigation is rated as Low because the impact can be mitigated. The Intensity would then

be Low (with Mitigation) as the receiving environment will not be affected. Mitigation is discussed further in

“Mitigation Measures”.

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8 MITIGATION MEASURES

All impacts must be considered under the Mitigation Hierarchy to arrive at an ecologically suitable solution.

The Mitigation Hierarchy is:

Avoidance: impact is prevented or substantially prevented (most preferred);

Reduction: impact is reduced in magnitude and/or significance;

Rectification: impact is mitigated after it has occurred, e.g. rehabilitation of areas disturbed by

construction;

Compensation: providing a substitute resource for a resource that has been lost because of the

project (e.g. “conservation offsets”);

No action (least preferred).

8.1 CONSTRUCTION

Impact 1: Loss of Cape Flats Dune Strandveld (Endangered) (Southern Patch)

This is a Significant impact that cannot be mitigated as the ecosystem has been rated as irreplaceable (due

to its unique abiotic features), as well as having Regional significance (being the only remaining patch of

CFDS on the Atlantic seaboard). This impact must be Avoided (No-Go)

Impact 2: Loss of Cape Flats Dune Strandveld (Endangered) (Northern Patch)

This impact can be entirely Avoided by utilising a wooden boardwalk as opposed to an impervious concrete

walkway. The boardwalk must remain on the granite batholith and avoid contact with any vegetation nior

shade it.

Impact 3: Loss of Cape Flats Dune Strandveld (Endangered) in poor condition (eastern limit of

Northern Patch)

Significance With Mitigation is rated as Medium which is the same without mitigation because thresholds

have been crossed and it is therefore in a lesser functioning state than the remainder of the vegetation. The

portion could no doubt be reverted to a state that is along a trajectory (“in transition”) to a similar previous

state, the real scenario however is one of making the resources available to do this. In biodiversity

management reality the resources do not exist for the management intensity that is required to revert this

portion to a more relevant state. Resources are more likely to be allocated to managing existing high

conservation value areas. For this reason the Mitigation recommended is Compensation. Transforming the

patch will not alter the vegetation lower down (seaward side) provided the hydrology is not altered

(excessive recharge). The level of compensation (funding of management activities) must be decided with

the City of Cape Town: Biodiversity Management.

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Impact 2: Loss of Cape Lowlands Freshwater Wetlands

Significance With Mitigation is rated as Medium because the impact can be mitigated to an extent where

the hydrological function is not impeded, but the wetland flora could be somewhat altered. The impact is

therefore Reduced.

To achieve Reduction in impact the proposed pedestrian walkway must be constructed in such a way that it

does not obstruct the flow of water. In order to achieve this, the walkway will have to be a bridge with all

the supports bedded into the exposed granite batholith. No supports are allowed in the actual wetland.

The impact will be reduced in that the hydrology will not be affected (thereby avoiding the cascading effects

associated with altered hydrology) but the flora will be moderately impacted by shading. The shading will

not eliminate the flora if the bridge is of a slat type that allows light through.

Impact 3: Loss of Southern Coastal Forest

Significance With Mitigation is rated as Low because the ecosystem is mostly transformed and does not

contribute to the ecological integrity of the site. Rectification is recommended as mitigation.

The trees can be moved and utilised in the Precinct for landscaping. Whilst Olea europaea subsp. africana is

known to respond favourably to transplanting it is not known whether Euclea racemosa is as forgiving. If,

however, the Precinct design is altered and the patch can be kept as a feature, with milkwood trees and

other aesthetically pleasing indigenous flora associated with Southern Coastal Forest added, then it would

be a positive outcome. However, there is no ecological reason for maintaining the patch. The trees however

are a valuable resource and should be utilised for landscaping if the patch cannot be incorporated into the

layout of the proposed Clifton Precinct.

8.2 OPERATIONS

Impact 1: Alteration of hydrology resulting in transformation of ecosystems

Significance With Mitigation is rated as Low because the impact can be mitigated.

Catchment hardening in particular is associated with increased recharge. It is therefore imperative that all

stormwater resulting from the proposed Clifton Precinct be diverted away from the downslope ecosystems.

Under no circumstances may any stormwater or run-off be allowed to discharge into the existing natural

vegetation downslope of the proposed development.

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9 CONCLUSION AND RECOMMENDATIONS

The proposed Clifton Precinct in its present layout will have Significant residual impacts. The layout must be

redesigned to take the patches of vegetation into account and Avoid them.

The patches of CFDS and CLFW must be avoided and the proposed layout re-designed to avoid these.

All milkwood, Sideroxylon inerme trees that are planted in the parking area at Clifton Fourth Beach must

be moved if they are going to be impacted by the development. Department of Agriculture, Forestry and

Fisheries (DAFF) must be consulted as to whether a licence will be required to move Protected Trees that

were planted.

The large gwarrie, Euclea racemosa tree in front of the garages at Clifton Fourth Beach must be retained

and incorporated into the design. It must not be moved.

The large gwarrie, E. racemosa trees situated between the tennis courts and the substation must be

incorporated into the design. They must not be moved.

A low-growing, multiple-stemmed milkwood, S. inerme shrub was found growing above the Law

Enforcement Offices inside the proposed Clifton Precinct (alongside the steps above the gate through the

palisade fence). This shrub has been severely damaged by vagrants (it comprises mostly dead wood) and

is not of conservation-value. A licence must be acquired from DAFF to destroy it.

All Invasive Alien Plants must be eradicated from the CFDS and CLFW and all the cut material must be

removed from site i.e. not left as brushpiles in the veld. .

City of Cape Town Biodiversity Management must be approached regarding conservation stewardship.

The CFDS and CLFW are of high conservation significance and in dire need of management intervention.

Acquisition of these patches into the Conservation Stewardship programme is essential for the continued

persistence of the natural vegetation.

A Biodiversity Management Plan must be compiled to guide the management activities required to

maintain persistence of the natural ecosystem and furthermore mitigate potential operational impacts.

Erf 491, Clifton has encroached beyond the boundaries of the erf onto the CFDS. The vegetation has

been partially transformed and developed into a garden with excessive irrigation that is also over-

recharging the wetland. The owner must be served a notice to cease this activity.

All trees used for landscaping must be of local origin. The City of Cape Town nursery in Hout Bay has

locally indigenous trees propagated from locally sourced seed. These must be used as opposed to those

sourced from commercial nurseries as the source of the seed may result in genetic contamination of local

populations.

All landscaping must be executed in accordance with the City’s landscaping policy.

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10 REFERENCES

ANONYMOUS, 2009. Threatened Ecosystems in South Africa: Descriptions and Maps. South African National

Biodiversity Institute & Department of Environmental Affairs and Tourism, Pretoria

MUCINA, L. & RUTHERFORD, M. 2006. Vegetation Map of South Africa, Lesotho and Swaziland. South

African National Biodiversity Institute, Pretoria.

PREPARED BY:

Robin Jangle

Biodiversity Specialist – NCC Environmental Services (Pty) Ltd.

M · 071 483 5504


REVIEWED BY:

Karien Potgieter Pri. Sci. Nat.

Senior Conservation Technician – NCC Environmental Services (Pty) Ltd.

M ·082 964 1667


mailto:[email protected]

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APPENDIX 1

Figure 1: Map showing the proposed Clifton Precinct in relation to the natural vegetation patches.

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Figure 2: Map showing the location and extent of natural vegetation patches at the proposed Clifton

Precinct.

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APPENDIX 2

Figure 3: Cape Flats Dune Strandveld Patch 1 immediately west of Erf 491, Clifton. Note the granite

batholith with marine sands.

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Figure 4: Cape Flats Dune Strandveld Patch 2 immediately south of the entrance to Glen Country Club. The vegetation is not transitional to Southern Coastal Forest.

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Figure 5: Cape Lowlands Freshwater Wetland immediately south of CFDS Patch 1. Note that the water seeps into the CFDS via the granite batholiths.

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Figure 6: Cape Lowlands Freshwater Wetlands viewed from the southern edge. This wetland receives

excessive recharge (from the sports fields immediately above it) as is evidenced by the excessive

growth of Typha capensis (brown grass-like foliage).

botanical assessment of the proposed clifton precinct ......proposed clifton precinct for city of...

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