11.1 Overview 11.2 Legislative and policy requirements

Duplication of the Southern Expressway | Project Impact Report

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11. Flora 11.1 Overview

This assessment of the flora of the project area, and the potential effects of the project on that flora, is based on a vegetation survey and a review of relevant literature and data.

11.2 Legislative and policy requirements

Table 11.1 summarises the relevant key legislation.

Table 11.1 Relevant legislation (flora)

Legislation Description Relevant to project Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) (Commonwealth)

Protects the environment from impacts on Matters of National Environmental Significance Requires assessment and approval of actions likely to have a significant impact on a Matter of National Environmental Significance

A number of flora species were identified through the EPBC Protected Matters Search Tool as potentially occurring in the project area; none were identified during project surveys Two ecological communities were flagged for the area; one was identified in the project corridor

Environment Protection Act 1993 (SA)

The overarching environmental legislation that deals with the protection of the environment and environmental offences; administered and enforced by the SA Environment Protection Authority In relation to flora, Part 4 Section 25 states: A person must not undertake an activity which pollutes, or might pollute the environment unless the person takes all reasonable and practicable measures to prevent or minimise any resulting environmental harm.

Construction and operation of the project must comply with the Act, including prevention of environmental harm as detailed in Part 4 Section 25 of the Act

Natural Resources Management Act 2004 (NRM Act) (SA)

Provides for the establishment of natural resources management boards in SA Promotes the sustainable use and management of SA’s natural resources Establishes an integrated management arrangement that recognises the intrinsic value of natural resources and provides for protection of biodiversity, water resources, catchments and land Provides for the prevention and control of ‘pest’ species: Natural Resources Management Regulations 2005 establishes ‘pest’ (flora and fauna species) management actions on a state basis

The project lies in the Adelaide and Mount Lofty Ranges Natural Resources Management (AMLR NRM) Region Declared weed species identified in the project area will need to be controlled/managed


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Legislation Description Relevant to project Native Vegetation Act 1991 (SA)

Provides incentives and assistance to landowners for the preservation and enhancement of native vegetation, and controls the clearance of native vegetation Focuses on retaining areas of remnant native vegetation, in particular in order to prevent further: reduction of biological diversity and

degradation of the land and its soil loss of quantity and quality of native

vegetation loss of critical habitat

Approval is required under the Act for the clearance of native vegetation

National Parks and Wildlife Act 1972 (SA)

Developed to establish and manage reserves Provides for the protection of native flora and fauna, and identifies flora and fauna species considered to be of conservation significance for the state

Species listed as being of conservation significance should be protected; potential impacts to these species should be avoided or minimised to ensure their protection into the future Six species of conservation significance were identified during project flora surveys); each was planted and are therefore not subject to the Act

Development Act 1993 Provides for planning and regulation of development in the state States that development approval is required if any tree that meets certain size requirements, is removed or impacted upon as part of the project

The project is located in metropolitan Adelaide; therefore, provisions of the Significant Tree legislation under the Act apply Numerous trees meeting the Significant Tree criteria were observed during flora surveys Significant trees within the proposed concept design will be individually assessed and, if no viable option for retaining them is found, applications for their removal prepared, as necessary

11.3 Assessment methodology

The flora assessment included:

a literature review of previous investigations a search of flora database records from local, South Australian and Australian governments

including the Biological Databases of South Australia (BDBSA), maintained by the Department of Environment and Natural Resources (DENR) and a Protected Matters Search of the Environment Protection and Biodiversity Act 1999 (EPBC Act)

field surveys using the methodology outlined in the DTEI modified Vegetation Survey Guidelines consultation with South Australian Government groups and key stakeholders


PAGE 11–3

assessment of impacts to flora based on the criteria outlined in the EPBC Act Matters of National Environmental Significance Significant Impact Guidelines Version 1.1 (DEWHA 2009) and the Native Vegetation Survey Impact Assessment Criteria

assessment of trees in the project area under the Development Act 1993 to determine whether they are classified as Significant Trees

review and application in accordance with DTEI’s Native Vegetation Removal Policy.

11.4 Existing conditions

11.4.1 Flora communities before European settlement

Much of the project area is located in what was primarily an Adelaide Plains environment with vegetation communities of (Kraehenbuehl 1996; City of Onkaparinga 2010b):

River Red Gum (Eucalyptus camaldulensis) and SA Blue Gum (Eucalyptus leucoxylon) Woodland (along Sturt River)

Mallee Box (Eucalyptus porosa), Stipa spp., Danthonia spp. Low Woodland on the plains in City of Marion and Mallee Box Woodland over limestone on the plains in Onkaparinga

Coastal daisy (Olearia axillaris) and Acacia spp. tall Shrublands in the coastal dunes Sheoak (Allocasuarina spp.) or Bush Pale Turpentine (Beyeria lechenaultii) Low Shrubland in the

coastal cliff zone Grey Box (Eucalyptus microcarpa) Woodland on deep red brown clays within the foothills,

escarpment, Onkaparinga Plains and central ranges River Red Gum Open Woodland on sandy river soils in the riverine systems Stringybark (Eucalyptus obliqua) Woodland in wetter areas on acidic soils in the upper ranges.

Widespread urbanisation and development has significantly altered the project area. Pre-European vegetation associations are either extremely reduced in habitat quality and viability, or no longer occur in the area.

11.4.2 Flora communities in the project area

In the heavily modified suburban environment of the project area, exotic, indigenous and non-local native vegetation has been planted in a distinctly amenity-focused landscape environment, with long linear areas of revegetation providing a visual screen for residential areas adjacent to the Southern Expressway.

The project area is situated in the Adelaide and Mount Lofty Ranges Natural Resources Management (AMLR NRM) Region and in the Flinders Lofty Block Bioregion (SEWPAC 2010a). This bioregion, classified under the Interim Biogeographic Regionalisation of Australia (IBRA), represents dominant landscape-scale attributes. Specifically, the project area falls within the Mount Lofty Ranges IBRA subregion and the Aldinga association of this bioregion. Only 3% of the Aldinga Association is mapped as remnant, of which 44% is protected in Heritage Agreements or under the South Australian National Parks and Wildlife Act 1972 (NPW Act) (Laut et al. 1977).

Flora surveys in November 2010 along the length of the project area indicated that there are two main vegetation types (EBS 2010a; Rural Solutions 2010):

Vegetation Association 1: Remnant native vegetation Vegetation Association 2: Planted scattered exotic and native trees and shrubs.

Figure 11.1 illustrates the locations of the vegetation associations.


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Scattered remnant trees recorded in Vegetation Association 1 during the field surveys are very large or mature, isolated from revegetation areas, and of different cohorts than the surrounding vegetation (EBS 2010a). Individual remnant trees of River Red Gum were recorded along the bank of Sturt River at the Main South Road interchange at Darlington but some may have been planted or regenerated. The largest trees nearest to the Sturt River were recorded individually as remnant; the remaining trees in the revegetated areas away from the river were recorded as ‘planted’ (Rural Solutions 2010).

11.4.2.1 Vegetation Association 1

Four areas were identified as possibly containing remnant vegetation; an additional area contained native grasses. The vegetation structure and composition of these areas appears to be naturally occurring and not recently planted (i.e. vegetation configuration was not in defined rows or clumps, and individuals were of a mixed age) (EBS 2010a).

Remnant Group 1

This small patch is located west of the project area in the northern portion of O’Halloran Hill Recreation Park. It is characterised by SA Blue Gum Woodland over Drooping Sheoak (Allocasuarina verticillata) and Olive (Olea europaea ssp. europaea) and the understorey highly degraded by Oat Grass (Avena barbata) and Wild Mustard (Brassica sp.) (EBS 2010a). Olive is a declared weed species under the NRM Act.

Remnant Group 2

This group is located adjacent to the project area, east of Adams Road. The original advice was that the patch was remnant but the flora survey determined that many species in the patch were actually planted (EBS 2010a). The vegetation is described as Kangaroo Thorn (Acacia paradoxa) Tall Open Shrubland with planted River Red Gum, Golden Wattle (Acacia pycnantha), Drooping Sheoak, Scarlet Bottlebrush (Callistemon rugulosus) and Totem Poles (Melaleuca decussata) over riparian species such as Narrow-leaf Bulrush (Typha domingensis) (EBS 2010a). It is possible that Lignum (Muehlenbeckia florulenta) and Kangaroo Thorn are remnant species. Further degrading the understorey are many weeds including Western Coastal Wattle (Acacia cyclops), Olive, Salvation Jane (Echium plantagineum) (declared weed species under the NRM Act), Prickly Lettuce (Lactuca serriola), Scabious (Scabiosa atropurpurea), Fennel (Foeniculum vulgare) and Oat Grass (EBS 2010a).

Remnant group 3

This remnant group dominates the Field River riparian environs west of the Southern Expressway at Young Street bridge and is described as Narrow-leaf Bulrush, Common Reed (Phragmites australis) Closed Sedgeland (EBS 2010a). Most other vegetation growing along the creek line is a mix of planted and invasive exotic species, with the exception of scattered River Red Gums, which may also be remnant or self-seeded from remnant individuals (EBS 2010a). The area is highly degraded by years of weed invasion and overall neglect; however, the eucalypts growing along Field River are in good condition and provide some low level of habitat to native wildlife species in a largely urbanised environment cleared of most of its native vegetation. The dense native understorey stands of reeds and bulrushes also make a valuable refuge to fauna species from exotic and native predators in the area (foxes, birds of prey, domestic cats and dogs).

Remnant group 4

This group of remnant vegetation is located near Beach Road interchange to the west of the project area and was found to consist of Grey Box Woodland with Dryland Tea-tree (Melaleuca lanceolata), Native Apricot (Pittosporum angustifolium), Drooping Sheoak over Mealy Saltbush (Rhagodia parabolica), Ruby Saltbush (Enchylaena tomentosa), Large-leaf Eutaxia (Eutaxia diffusa), Austrostipa

Southern Expressway Duplication Project Impact Report

Vegetation associationswithin project area

Figure 11.1

Stu rt River

Field River

Christies Creek

Onkaparing a R iver

Happy ValleyResevoirTH

E CO

VE R

D

HAPP

Y VAL

LEY D

R

DYSO

N RD

MAIN SO

UTH R

D

YOUNG ST

St Vincent'sGulf

STATES RD

HONEYPOT RD

Remnant group 4see Figure 11.2

Main South RoadInterchange atOld Noarlunga

Main South RoadInterchange at

Darlington

Beach RoadInterchange

Sherriffs RoadInterchange

Panalatinga RoadInterchange

PANALATINGA RD

FLAXMILL RD

COXS H ILL RD

BAINS RD

BRIGHTON RD

SEACOMBE RD

COMMERCIAL RD

SEAFORD RD

ELIZA BETH RD

BEACH RD

FLAGSTAFF RD

GULFVIEW RD

MURRAY RD

LONSDALE RD

STURT RD

PENNEYS HILL RD

BLACK RD

O'SULLIVAN BEACH RD

WHEATSHEAF RD

MARION RD

PIMPALA RD

KENIHANS RD

SHERRIFFS RD

MORPHETT RD

MAJORS RD

LANDER RD

!

!

!

ELIZABETH

NOARLUNGA

ADELAIDE

Concept designVegetation association 1Vegetation association 2

Z Scale @ A4 1:85,0000 1,000 2,000500

m

Remnant group 1

Remnant group 2

Remnant group 3

Native grassland


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spp. and Austrodanthonia spp. (Rural Solutions 2010). The Grey Box trees were measured at up to 11 metres in height, a medium height for this species (Rural Solutions 2010).

Figure 11.2 shows the location of this remnant group in proximity to the project area at Beach Road interchange.

Native grassland

A small dense patch of Kangaroo Grass (Themeda triandra) Grassland was located on the northern side of Christie Creek crossing, west of the project area, with Common Tussock Grass (Poa labillardieri var. labillardieri) also prominent throughout (EBS 2010a). Exotic species found included Olive, Large Quaking grass (Briza maxima), Oat Grass and Ribwort (Plantago lanceolata var. lanceolata). It appears unlikely that this patch has been planted given the dense configuration of individuals and the insignificant location (EBS 2010a). It probably self seeded from remnant individuals in the area (EBS 2010a).


Vegetation Association 2, of planted exotic species and scattered natives, is widespread in the project area and represents previously revegetated areas (EBS 2010a). Landscaping and revegetation after the completion of both stages of the Southern Expressway in 1997 (Stage 1: Darlington to Reynella) and 2001 (Stage 2: Reynella to Old Noarlunga) has continued since. There have been recent efforts to confine plantings to local indigenous species mix but many other areas combine exotic and non-local native species.

Many tree species in this association have been grown for their amenity value and are predominantly local Eucalyptus species including River Red Gum, Grey Box, Mallee Box and SA Blue Gum. Mid-storey species featuring prominently in the revegetation areas include Sticky Hop Bush (Dodonaea viscosa ssp. spathulata), Southern Cypress Pine (Callitris gracilis), Drooping Sheoak, Kangaroo Thorn, Golden Wattle, Wreath Wattle (Acacia acinacea), Sticky Boobialla (Myoporum viscosum), Native Apricot and Twiggy Daisy Bush (Olearia ramulosa).

Some revegetation areas were found to be more aligned with species found in River Red Gum Woodlands associated with riparian environments, particularly those areas close to creeks, drainage areas and small soaks/sumps (Rural Solutions 2010).

Many areas were found to contain exotic plant varieties: some intentionally planted and some vigorous competitor/weed species invaders, including Oat Grass, Olive, Artichoke Thistle (Cynara cardunculus ssp. flavescens), Western Coastal Wattle, African Boxthorn (Lycium ferocissimum), Tangier Pea (Lathyrus tingitanus) and False Caper (Euphorbia terracina) (EBS 2010a). Olive, Artichoke Thistle, African Boxthorn and False Caper are declared weed species under the NRM Act.

Overall, the condition of this vegetation association varies considerably, from excellent examples of well-managed indigenous plantings to extremely degraded and highly modified areas dominated by exotic or non-local native overstorey species coupled with aggressive weeds in the understorey (EBS 2010a).

11.4.2.3 Aquatic flora

Several important waterways and associated environments lie in and around the project area. They include Sturt River (and the associated Warriparinga Wetlands), Field River and its tributaries (including Glenthorne Creek, Panalatinga Creek and Grant Creek), Christie Creek, Hackham Creek and Onkaparinga River in the south.


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The Sturt River embankments in the northern end of the project area are currently lined with River Red Gums of various ages including some very old significant trees (as defined by the Development Act 1993). However, the understorey is modified and contains native and exotic species. Significant restoration works (including plantings and weed control) have introduced native species of high diversity.

The Warriparinga Wetlands were developed in 1998 to improve the water quality of Sturt River. More than 8,000 trees, and 20 varieties of reeds and aquatic plants have been planted (City of Marion 2010b).

The majority of the original native vegetation in Field River catchment has been cleared or modified by agriculture and mining; the remaining native vegetation covers only a small percentage of the catchment area. These pockets of remnant vegetation are highly fragmented and isolated, and are vulnerable to invasion by exotic species. They include species such as Narrow-leaf Bulrush, Common Reed and River Red Gum (AMLR NRM Board 2010; EBS 2010a).

Christie Creek and its tributaries have been highly modified with realignment and artificial lining of the watercourse to address flooding and erosion. Across the catchment, most original native vegetation has been cleared; only 5% of remnant vegetation remains in isolated, fragmented pockets. Very little remnant riparian vegetation has good condition; typically remnants have large Eucalypts with most other native vegetation removed (AMLR NRM Board 2007).

The Onkaparinga River and its catchment is a major source of drinking water for metropolitan Adelaide and the catchment has been modified for the purposes of harvesting water (AMLR NRM Board 2010). The main tributary in the project area is Hackham Creek which contains stands of native vegetation upstream, and some reed beds downstream of the project area (Transport SA 1998).

The wettest parts of the project area have been recreated as small wetlands, with associated wetland plants such as Swamp Wattle (Acacia retinoides), Cyperus spp., Eleocharis spp., Schoenoplectus spp., Lignum (Muehlenbeckia florulenta), Common Reed and Narrow-leaf Cumbungi (Typha domingensis) (Rural Solutions 2010). In these areas natural regeneration is making revegetated understorey and naturally regenerated specimens impossible to separate.

11.4.3 Weed species in the project area

Given the highly modified condition of the Southern Expressway corridor, the flora surveys identified that the understorey in the project area was mostly dominated by exotic grasses and herbaceous weeds (EBS 2010a). Many of these species are known invaders of open and disturbed areas. It was also observed that there had been an effort to control weeds, such as Artichoke Thistle, in some areas and replanting has suppressed understorey exotics to some extent (EBS 2010a).

Olive is a declared weed species under the NRM Act with significant potential to invade natural bushland. The project area was found to contain a significant number of mature established Olive trees as well as historic commercial groves (EBS 2010a). Scattered self-seeded Olive saplings were noted in numerous locations in the survey area, probably sourced from the mature individuals (EBS 2010a).

Artichoke Thistle, also a declared weed species under the NRM Act, was found to be widespread throughout the project area and in extreme infestations some places (EBS 2010a). There have been some control works by groups such as Friends of the Onkaparinga River National Park, and DENR in O’Halloran Hill Recreation Park but many dense stands are proliferating (EBS 2010a).

Southern Expressway Duplication Project Impact Report

Vegetation association 1Remnant group 4

Figure 11.2

BEACH RD

!

!

NOARLUNGA

DARLINGTON

Concept designRemnant group 4 (Eucalyptus microcarpa)

Z Scale @ A4 1:2,0000 20 4010

m


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Approximately 400 species of exotic plants were identified in the project area during the flora surveys and through review of existing flora survey data from the immediate vicinity (EBS 2010a; Rural Solutions 2010; DENR 2010).

Table 11.2 lists some dominant and declared weeds found in the project area (EBS 2010a; Rural Solutions 2010; DENR 2010).

Table 11.2 Weed species in the project area

Species Common name Acacia longifolia Sallow Wattle Acacia saligna Golden Wreath Wattle Acacia cyclops Western Coastal Wattle *Allium triquetrum Three-corner Garlic *Allium vineale Field Garlic Asclepias rotundifolia Broad-leaf Cotton-bush *+Asparagus asparagoides Bridal Creeper *Asphodelus fistulosus Onion Weed *Cardaria draba Hoary Cress *Chrysanthemoides monilifera Boneseed Cichorium intybus Chicory *Convolvulus arvensis Field Bindweed *Cynara cardunculus Artichoke Thistle Cynodon dactylon Couch Grass Cyperus eragrostis Drain Flat-sedge Diplotaxus tenuifolia Lincoln Weed *Echium plantagineum Salvation Jane Emex australis Three-corner Jack Foeniculum vulgare Fennel Fraxinus rotundifolia Desert Ash Helminthotheca echiaides Ox Tongue *Lycium ferocissimum African Boxthorn Lactuca serriola Prickly Lettuce Malvella parvifolium Mallow *Olea europaea Olive Tree *Opuntia spp. except O. ficus-indica Prickly Pear *Oxalis pes-caprae Soursob Pennisetum clandestinum Kikuyu *Pinus halepensis Aleppo Pine Polygonum aviculare Wireweed Rhaphanus raphanistrum Wild Radish Rapistrum rugosum Wild Turnip Scabiosa atropurpurea Scabious


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Species Common name Sonchus oleraceus Sow Thistle Sorghum halepense Johnson Grass *Tribulus terrestris Caltrop

* species declared under the Natural Resources Management Act 2004 + Weed of National Significance

A reduction of exotic species, using various control techniques, would substantially benefit both the under and middle storey vegetation strata. Proposed measures to reduce the likelihood of spreading weeds during the construction and operation of the project are included in Section 11.7.

11.4.3.1 Phytophthora

Phytophthora is a plant pathogen that causes dieback in plants. It occurs in native bushland, farmland, nurseries and gardens (Phytophthora Technical Group 2006). It is a major threat to some of Australia’s threatened flora and fauna species. The project corridor has been assessed as a low risk phytophthora area and although no indications of its presence were noted at the time of the vegetation survey, controls according to TSD Operational Instruction 21.3 (Phytophthora (Dieback Control)) shall be implemented if it is found in the project area.

11.4.3.2 Mundulla Yellows

The term Mundulla Yellows refers to a phenomenon that causes plant dieback, yellowing of foliage and inter-veinal chlorosis of the leaves.

No indication of Mundulla Yellows was specifically noted during the flora surveys and none of the trees were recorded as showing signs of excessive dieback (EBS 2010a; Rural Solutions 2010).

11.5 Species and ecological communities of conservation significance

The EPBC Act Protected Matters database was searched to determine the potential presence of any matters of National Environmental Significance that may occur in, or may relate to, the project area. The search included a 2 kilometre buffer around the boundary of the Southern Expressway corridor.

The search identified the potential presence of 13 threatened plant species in the project area (SEWPAC 2010b) and the potential presence of two nationally threatened ecological communities.

A search of the Biological Database of South Australia (BDBSA), maintained by DENR, was conducted to obtain an inventory of flora species previously recorded in the project area, including species listed under the EPBC Act and the NPW Act. Species lists from the November 2010 surveys were also compiled and species of conservation significance observed during these surveys were recorded.

The BDBSA records 993 flora species (including approximately 400 exotic species) for the project area(DENR 2010). Many of these records are from historic surveys (i.e. more than 20 and up to 100 years ago) and it is very unlikely that many of the species still occur in the area given recent development. However, the list gives an indication of the variety of species that previously inhabited the area (EBS 2010a). The Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South Eastern Australia ecological community is recorded as occurring in the project area. An additional 29 species protected under the NPW Act are listed as potentially occurring in the project area (EBS 2010a; Rural Solutions 2010).


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Table 11.3 outlines the species and ecological communities of conservation significance potentially occurring in the project area, and the 38 flora species protected under the NPW Act identified as potentially occurring in the project area. The table also notes the likelihood that these communities and species currently occur in the project area.

Table 11.3 Threatened species and ecological communities of conservation significance in the project area

Species Common name

EPBC Act

rating

NPW Act

rating

Likelihood of occurrence in project area

Identified during

surveys Ecological community Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South Eastern Australia

EN Very Likely: results of the flora survey indicate that this ecological community occurs adjacent to the Beach Road interchange

Yes

Peppermint Box (Eucalyptus odorata) Grassy Woodland of South Australia

CE Unlikely: Peppermint Box trees occur in some areas but are considered to be planted and not remnant fragments of threatened ecological communities

No

Flora species Allocasuarina robusta

Mount Compass Oak bush

EN E Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species; any occurrences would be the result of planting (this species was recorded approximately 2 km east of the project area in Sturt Gorge Conservation Park on three occasions in September 2001)

No

Caladenia argocalla White Beauty Spider orchid

EN E Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Caladenia brumalis Winter Spider-orchid

VU V Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Caladenia conferta Coast Spider-orchid

EN E Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Euphrasia collina ssp. osbornii

Osborne’s Eyebright

EN E Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No


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Species Common name

EPBC Act

rating

NPW Act

rating


Identified during

surveys Glycine latrobeana Clover

Glycine EN V Unlikely: given the modified

nature of the project area, suitable habitat for this species is unlikely in the project area

No

Prasophyllum pallidum

Pale Leek-orchid

VU Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Prasophyllum pruinosum

Plum Leek orchid

EN V Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Prasophyllum validum

Mount Remarkable Leek orchid

VU V Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Pterostylis cucullata Leafy Greenhood

VU Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Thelymitra cyanapicata

Blue Top Sun-orchid

CE E Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Thelymitra epipactoides

Metallic Sun-orchid

E E Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Veronica derwentiana subsp. homalodonta

Mount Lofty Speedwell

CE Unlikely: given the modified nature of the project area, suitable habitat for this species is unlikely in the project area

No

Acacia dodonaeifolia

Hop bush Wattle

R Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting (EBS 2010a)

No

Acacia genistifolia Broom Wattle

E Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Acacia iteaphylla Flinders Ranges Wattle

R Very likely: this species was identified in the project area but was planted and not present due to natural generation

Yes


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Species Common name

EPBC Act

rating

NPW Act

rating


Identified during

surveys Amphibromus archeri

Pointed Swamp Wallaby grass

R Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Austrodanthonia tenuior

Short-awn Wallaby grass


No

Austrostipa densiflora

Fox-tail Spear grass


No

Austrostipa gibbosa Swollen Spear grass


No

Austrostipa multispiculis


No

Austrostipa tenuifolia

R Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting (EBS 2010a)

No

Bothriochloa macra Red-leg Grass


No

Carex bichenoviana U Highly likely: this species was found as a regenerating native sedge in weed patches and was planted in some revegetated areas

Yes

Carex gaudichaudiana

Tufted Sedge

U Highly likely: this species was found in revegetated areas of the project area

Yes


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Species Common name

EPBC Act

rating

NPW Act

rating


Identified during

surveys Cladium procerum Leafy Twig

rush R Unlikely: given the modified

nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Correa glabra var. leucoclada

Rock Correa R Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Dianella longifolia var. grandis

Pale Flax lily R Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Dianella porracea Pale Flax lily V Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Diplachne parviflora (NC)

Small-flower Beetle grass


No

Eucalyptus fasciculosa

Pink Gum R Highly likely: this species was identified in the project area but was planted and not present due to natural generation

Yes

Glycine tabacina Variable Glycine

V Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Logania saxatilis Rock Logania


No

Maireana decalvans

Black Cotton bush

E Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No


PAGE 11–13

Species Common name

EPBC Act

rating

NPW Act

rating


Identified during

surveys Myoporum parvifolium

Creeping Boobialla

R Highly likely: this species was identified in the project area but was planted and not present due to natural generation

Yes

Orobanche cernua var. australiana

Australian Broomrape


No

Pimelea curviflora var. gracilis


No

Ptilotus erubescens Hairy tails R Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

Senecio hypoleucus

Pale Groundsel

R Very likely: this species was found in a revegetated patch in the project area; it may have regenerated naturally or have been planted

Yes

Thelymitra grandiflora

Great Sun orchid


No

Thelymitra holmesii Blue Star Sun orchid

V Unlikely: given the modified nature of the project area, it is unlikely that there is suitable habitat for this species in the project area; any occurrences would be the result of planting

No

EPBC Act and NPW Act Ratings: CE – Critically Endangered, EN/E – Endangered, VU/V – Vulnerable, R – Rare, U – Uncommon

Six of the threatened species protected under the NPW Act were identified during the flora surveys but all were considered to be planted in revegetation areas (EBS 2010a). Three of these species – Pink Gum, Creeping Boobialla and Flinders Ranges Wattle – are rated as Rare under the NPW Act; the remaining three species – Pale Groundsel, Tufted Sedge and Carex bichenoviana – are rated as Uncommon under the NPW Act (Rural Solutions 2010; EBS 2010a).

Two ecological communities listed as threatened under the EPBC Act were identified in the Protected Matters Search as potentially occurring in the project area. The Peppermint Box (Eucalyptus odorata) Grassy Woodland of South Australia ecological community was not identified during the flora surveys


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nor through the review of literature and data, and is thus not discussed further (EBS 2010a; Rural Solutions 2010). The Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South-Eastern Australia ecological community was found adjacent to the Southern Expressway corridor at the Beach Road interchange (Rural Solutions 2010).

Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South-Eastern Australia ecological community

This ecological community occupies a landscape zone transitional between semi-arid communities and the temperate woodlands and forests of the lower slopes and ranges (Threatened Species Scientific Committee 2010). Many of the plant species present are widespread or occur in other vegetation types that adjoin or integrate with the ecological community. The Threatened Species Scientific Committee (2010) identified its key diagnostic characteristics:

The ecological community occurs on low slopes and plains from central NSW through northern and central Victoria into South Australia. Disjunct occurrences are known from near Melbourne and the Flinders–Lofty Block Bioregion of South Australia.

The vegetation structure of the community is typically a woodland to open forest.

The tree canopy is dominated (> 50% canopy crown cover) by Grey Box. Other tree species may be present in the canopy and, in certain circumstances, may be co-dominant with Grey Box but are never dominant on their own.

The mid-layer comprises shrubs of variable composition and cover, from absent to moderately dense. The mid-layer usually has a crown cover of less than 30% with local patches up to 40% crown cover.

The ground layer also is highly variable in development and composition, in ranging from almost absent to mostly grassy to forb-rich. Ground layer flora commonly present includes: Austrodanthonia spp., Austrostipa spp., Elymus spp., Entreropogon spp., Dianella spp. and Lomandra spp.; and one or more of the chenopod genera: Atriplex spp., Chenopodium spp., Einadia spp., Enchylaena spp., Maireana spp., Salsola spp. and Sclerolaena spp.

Derived grasslands are a special state of the ecological community, whereby the canopy and mid layers have been mostly removed to <10% crown cover but the native ground layer remains largely intact, with 50% or more of the total vegetation cover being native.

The disjunct occurrence of the community in the Flinders–Lofty Block shows some regional variation in vegetation structure and composition (Threatened Species Scientific Committee 2010).

Remnant group 4 is a threatened ecological community under the EPBC Act: Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South-Eastern Australia (Rural Solutions 2010). This patch of vegetation is located to the west of the project area adjacent to the Beach Road interchange (Figure 11.2).

11.6 Effects of the project on existing flora

The project area has been substantially modified through urban development and construction of roads and other infrastructure. Land use directly surrounding most of the project area is predominantly residential housing, light industry, pedestrian/cycling paths, roads and the occasional block of open vacant land.


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In the general vicinity there are several areas of environmental merit: Onkaparinga River National Park and Onkaparinga River Recreation Park, O’Halloran Hill Recreation Park, and various areas of remnant and non-remnant vegetation previously discussed (e.g. riparian habitat along Field River, remnant patch of Grey Box and artificial wetlands).

Both Onkaparinga River National Park and Recreation Park are outside the project area and will not be impacted by the project.

The vegetation in O’Halloran Hill Recreation Park was almost entirely cleared for agriculture and most remaining vegetation was replanted as early as the 1970s (Department for Environment and Heritage 2008). Some vegetation in the road corridor in O’Halloran Hill Recreation Park may need to be removed.

The project area supports zones of riparian vegetation associated with Field River, Christie Creek and various stormwater overflow areas and small wetland depressions. In addition, the project area supports revegetated mixed woodland and shrubland strips, mixed exotic tree plantings and scattered mature Eucalyptus species, which are either remnants or plantings (EBS 2010a).

The vegetation in the project area is considered to contribute significantly to the biodiversity of the region, particularly those areas containing mature eucalypts and remnant vegetation (EBS 2010a).

A direct effect of the construction of the project is removal of vegetation, including native (Vegetation Association 1), planted and exotic (Vegetation Association 2) species.

11.6.1 Construction


Native vegetation (remnant group 4)

Remnant group 4, located west of the project area at the Beach Road interchange, contains Grey Box trees and other remnant flora species comprising the threatened ecological community Grey Box (E. microcarpa) Grassy Woodlands and Derived Native Grasslands of South-Eastern Australia (Rural Solution 2010). Remnant group 4 contains a total of 134 remnant individual trees and shrubs (Rural Solutions 2010).

Remnant group 4 is part of a Trees for Life, Bush for Life conservation initiative, which has been supported by DTEI since it began in 2004. The management measures of the Bush for Life conservation group to reduce weed infestation and encourage the growth and recruitment of native species have led to an increase in native species in the understorey (Trees for Life 2010).

The project will not directly impact on the area of this threatened ecological community at Beach Road interchange. The proposed concept design for the interchange locates the roadway immediately to the east of the threatened community. Management measures will be implemented at this location to minimise indirect impacts during construction.

Native vegetation (remnant groups 1–3 and native grassland)

Based on the proposed concept design of the project, remnant groups 1–3 and the native grasslands may have some vegetation removed during construction (Table 11.4).


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Table 11.4 Potential clearance of remnant groups 1–3 and native grassland

Native vegetation

Location Area (ha) Total remnant

vegetation Potentially

affected Remnant group 1 Remnant Blue Gum patch 0.05 0.04 Remnant group 2 West of project area, east of Adams Road 0.32 0.05 Remnant group 3 Field River 1.2 0.67 Native grassland North of Christie Creek, west of project area 0.01 0.01

Many Rare, Vulnerable or Endangered flora species found in the project area were part of revegetation programs and are located in planted areas (Rural Solutions 2010). Revegetated plants are not covered under the Native Vegetation Act 1991, unless they were planted as a condition under the Native Vegetation Act before clearance. Flora surveys of the project area identified the presence of significant trees as defined by the Development Act. Removal of any of these trees during construction will require the approval of the Development Assessment Commission.

Threatened species identified as potentially occurring in the project area, are actually considered to be highly unlikely to occur here, due to the highly modified nature of the project area. This is particularly true for many of the orchid species (EBS 2010a; Rural Solutions 2010). The clearance or disturbance of native vegetation in the project area is therefore not considered likely to cause a significant impact to those flora species listed as threatened under the EPBC Act or the NPW Act, as defined in the Matters of National Environmental Significance, Significant Impact Guidelines 1.1 (DEWHA 2009).


Based on the proposed concept design, the final and/or exact extent of vegetation clearance within Vegetation Association 2 is currently unknown and will need to be further investigated during the detailed design stage. However, the vegetation in this area is composed of planted exotic species and scattered natives from previously revegetated areas.

11.6.2 Operation

Potential effects to native vegetation (including threatened species and ecological communities) from the operation of the duplicated Southern Expressway primarily include edge effects on habitats immediately adjacent to the carriageway. These edge effects may comprise air quality impacts (e.g. exhaust and dust), potentially contaminated runoff from the carriageway, introduction of new weed and pest species, and exacerbation of existing weed infestations. Genetic isolation due to the development of a roadway between two populations of a native vegetation community or species population would also be an issue if the existing Southern Expressway had not already been developed.

The region within which the project is situated is highly degraded, and most vegetation consists of degraded, weedy and planted species. The existing Southern Expressway already divides populations and communities. A significant impact on native vegetation and threatened species and communities due to the operation of the project is therefore unlikely.

11.6.3 Limitations

The flora surveys were conducted during spring and while the majority of plant species should be identifiable at this time, it is possible that not all flora species were identified due to a lack of


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distinguishing features. Thus there is a chance that species of conservation significance may be present in the project area.

Records of historic surveys maintained by the Department of Environment and Natural Resources in the BDBSA may be inaccurate or incomplete. These surveys have not necessarily been undertaken throughout all seasons or specifically in the project area. The data indicate which species have been identified as occurring in the region but cannot be used to determine which species do not occur there.

This assessment has not considered the cumulative impacts of construction or operation of other road networks, industry or residential developments. It considers only potential impacts associated with construction and operation of the project based on the concept design and level of information.

11.7 Mitigation measure to minimise the effects

Before construction of the project begins, a construction environmental management plan (CEMP) will be developed by the appointed contractor. It will include sub-management plans such as a weed management plan and a soil, erosion and drainage management plan. Implementation of the CEMP will help minimise effects to flora during the design, construction and implementation of the project by adopting principles and implementing measures such as those listed in Table 11.5.

Table 11.5 Management and mitigation measures to reduce the effects on flora

Project stage Potential impact Mitigation/management measures Design Loss of native flora Identify species, or species habitat, of conservation

significance in the project area Identify significant trees in the project area Design the project to limit the removal of native vegetation, in

particular to avoid the Grey Box (Eucalyptus microcarpa) Grassy Woodland and Derived Native Grasslands of South-Eastern Australia ecological community adjacent to the Beach Road interchange

Design the project to ensure surface water quality is not decreased through construction and/or operation of the new road corridor


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Project stage Potential impact Mitigation/management measures Construction Removal of native

flora habitat Spread of weeds and biological pathogens (i.e. Phytophthora) species Removal of amenity plantings

Implement a construction environmental management plan with measures such as: confine vehicle access to existing roads where possible to

reduce the spread of weeds do not dump materials/waste or divert drainage lines that

will impact native vegetation during construction develop a weed management plan for the project and

induct all contractors in this plan manage top soil containing weed seeds appropriately to

prevent the spread of weeds mark all vegetation for removal to minimise potential for

more than the required vegetation be removed place fencing around native vegetation located within

construction premises, which is not being removed as a consequence of the proposed project

clean up any pollution events (i.e. spilling of hydrocarbons) immediately to minimise impact on native vegetation

ensure any imported fill is clean and does not contain exotic species or propagules of exotic species

clean all earthmoving machinery of soil and vegetation material before entering or exiting the site

induct all site personnel and ensure they are aware of mitigation measures to be implemented to reduce impacts to flora and fauna

do not permit laydown areas within the designated no go area near the identified Grey Box (E. microcarpa) Grassy Woodlands and Derived Native Grasslands of South-Eastern Australia and require hand digging around vegetation

landscape and revegetate cleared areas implement DTEI: Phytophthora (Dieback) Control

Operational Instruction 21.3 (as required) adopt an adaptive management approach to identify

impacts associated with construction of the road network and develop or alter processes/procedures to eliminate or minimise these impacts

Operation Degradation of flora habitat adjacent to the project footprint

Maintain any rehabilitated areas including weeding, watering and replacement of dead plant stocks as necessary

Adopt an adaptive management approach to identify impacts associated with the operation of the road network and develop or alter processes/procedures to eliminate or minimise these impacts

Consider the local environment in landscaping and rehabilitation works and use indigenous species to enhance the local biodiversity

Control litter in the project area Control vegetation appropriately to prevent fire


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11.7.1 Significant environmental benefit and DTEI offset

The value of native vegetation for social, economic and ecological benefits is increasingly being recognised. Native vegetation in South Australia is protected by the Native Vegetation Act and Native Vegetation Regulations 2003. The purpose of the legislation is to prevent all broad-scale clearance, minimise smaller-scale clearance, and enhance and restore native vegetation in South Australia.

The Native Vegetation Council (NVC), established under the Native Vegetation Act , is responsible for advising the Minister on the preservation and enhancement of native vegetation, and in determining applications to clear native vegetation in South Australia.

For removal of native vegetation associated with the project, an application will be submitted to the NVC outlining how DTEI proposes to offset the impact of removal of this native vegetation. Significant environmental benefit (SEB) is the NVC’s preferred way to offset removals in South Australia. SEBs can be a monetary contribution into the NVC’s fund, which then is used to promote and enhance native vegetation growth and restoration in the state, or can be direct offsets through site rehabilitation with the same habitat types as those being removed.

As a requirement of the Native Vegetation Act, DTEI will provide SEBs to offset the removal of native vegetation for the project. A significant portion of the vegetation to be removed in the project area is amenity planting. DTEI’s Vegetation Offset Guidelines outline the requirements for remediation measures to offset the loss or damage to vegetation resulting from its construction activities. These guidelines also indicate the SEB offset area that would be required as part of the project, depending on the quality of native vegetation present in the project area.

Any vegetation requiring clearance in the project corridor, and for the project, will be replaced in accordance with DTEI’s Vegetation Offset Guidelines.

11.8 Conclusion

Native vegetation in the project area has been highly altered through the previous development of the Southern Expressway and through urbanisation. The majority of the vegetation in the project corridor is poor-to-moderate quality planted natives and exotic species, including amenity plantings from the first two stages of the Southern Expressway in 1997 and 2001. Vegetation clearance for the project, primarily on the western side of the current alignment, will be undertaken in line with DTEI’s Vegetation Removal Policy and Vegetation Offset Guidelines..

Four areas of remnant vegetation as well as an area of native grassland were identified in the project area. Remnant group 4 located at Beach Road interchange, is a threatened ecological community under the EPBC Act: Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South-Eastern Australia. These areas, along with the revegetated areas associated with Field River, Christie Creek and other stormwater ponds, represent vegetated habitat for fauna and an important link to the broader region.

Effects on native or remnant vegetation will be managed by implementing the measures outlined in Section 11.7. Specifically, the removal of native vegetation will be minimised through detailed design of the project footprint, and management of identified areas of native vegetation and of weed species while construction is underway.

On completion of construction works, the project area will be rehabilitated and revegetated in targeted areas of the corridor. The provision of SEB will help to minimise effects on native vegetation in the project corridor.


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11.1 Overview 11.2 Legislative and policy requirements

Documents

Transcript of 11.1 Overview 11.2 Legislative and policy requirements