environmental report northern expresswaynorthern fl ora technicalpaper
FLORA TECHNICAL PAPER
Northern Expressway
Flora
Technical Paper
28 February 2007
Prepared by:
Kellogg Brown & Root Pty Ltd
186 Greenhill Road Parkside SA 5000
Telephone: + 61 8 8301 1234 Facsimile: + 61 8 8301 1301
Prepared for:
Department for Transport, Energy and Infrastructure
33-37 Warwick Street Walkerville SA 5081
PO Box 1 Walkerville SA 5081
Telephone: 1300 658 621 Facsimile: + 61 8 8343 2005 Email: [email protected]
© Kellogg Brown & Root Pty Ltd, 2007
Limitations Statement The sole purpose of this report and the associated services performed by Kellogg Brown & Root Pty Ltd (KBR) either directly or through its associates, Sinclair Knight Merz Pty Ltd (SKM) and QED Pty Ltd (QED) is to document the effects on vegetation and flora of the Northern Expressway project in accordance with the scope of services set out in contract reference 05C152 between KBR and the Department for Transport, Energy and Infrastructure (DTEI) (‘the Client’). That scope of services was defined by the requests of the Client, by the time and budgetary constraints imposed by the Client, and by the availability of access to the site.
KBR derived the data in this report primarily from document references as listed in Section 6 of this report, consultation with the Client and stakeholders as listed in Section 2 of this report, and site inspection of the region as limited by constraints on access to private property at the time of preparation of this report, and the prevailing dry environmental conditions (site inspection dates are listed in Section 2 of this report). The passage of time, manifestation of latent conditions or impacts of future events may require further exploration at the site and subsequent data analysis, and re-evaluation of the findings, observations and conclusions expressed in this report.
In preparing this report, KBR has relied upon and presumed accurate certain information (or absence thereof) relative to the site provided by the Client and others identified herein. Except as otherwise stated in the report, KBR has not attempted to verify the accuracy or completeness of any such information.
No warranty or guarantee, whether express or implied, is made with respect to the data reported or to the findings, observations and conclusions expressed in this report. Further, such data, findings, observations and conclusions are based solely upon information supplied by the Client in existence at the time of the investigation.
This report has been prepared on behalf of and for the exclusive use of the Client, and is subject to and issued in connection with the provisions of the agreement between KBR and the Client. KBR accepts no liability or responsibility whatsoever for or in respect of any use of or reliance upon this report by any third party.
Revision History
Signatures Revision Date Comment Originated Checked Authorised by by by 0 21/02/2007 AEC517.003-G-REP-002 RJA NB MEJ Issued for Client review 1 28/02/2007 AEC517.003-G-REP-002 RJA NB MEJ Issued for use
Table of Contents
1 Introduction 1 1.1 Project description 1 1.2 Topic explanation 2 1.3 Legislative requirements, policies and definitions 2 1.3.1 National 2 1.3.2 State 2 1.3.3 Department for Transport, Energy and Infrastructure 4 1.3.4 Local council 4 1.4 Sources 4 1.4.1 Significance criteria 4 2 Methods and materials 7
3 Existing conditions 9 3.1 Description of existing conditions within corridor 9 3.1.1 Existing regional environment 9 3.1.2 Pre-European settlement vegetation communities and flora 10 3.1.3 Vegetation and flora along the Northern Expressway 14 3.1.4 Vegetation and flora along the Port Wakefield Road Upgrade 15 3.2 Northern Expressway vegetation and flora survey information 15 3.2.1 Vegetation communities 15 3.2.2 Threatened communities 16 3.2.3 Flora (species) 18 3.2.4 Threatened species 19 3.2.5 Introduced and pest plant species 22 3.2.6 Threatening processes and plant pathogens 23 3.3 Port Wakefield Road Upgrade vegetation and flora survey information 24 3.3.1 Vegetation communities 24 3.3.2 Threatened communities 26 3.3.3 Flora (species) 27 3.3.4 Threatened species 27 3.3.5 Introduced and pest plant species 28 3.3.6 Threatening processes and plant pathogens 28 3.4 Summary of existing conditions 30
4 Effects of the project upon existing conditions 31 4.1 Environmental management 32 4.1.1 Principles adopted to minimise effects 32 4.1.2 Measures to minimise effects during planning and design 32 4.1.3 Measures to minimise effects during construction 34 4.1.4 Measures to minimise effects during post-construction 34
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5 Conclusions 35 5.1 Northern Expressway 35 5.1.1 Environment Protection and Biodiversity Conservation Act 36 5.1.2 National Parks and Wildlife Act 36 5.1.3 Development Act 36 5.1.4 Native Vegetation Act 36 5.1.5 Other species of conservation significance 37 5.2 Port Wakefield Road Upgrade 37 5.2.1 Environment Protection and Biodiversity Conservation Act 38 5.2.2 National Parks and Wildlife Act 38 5.2.3 Development Act 38 5.2.4 Native Vegetation Act 38 5.2.5 Other species of conservation significance 38 6 References 39
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List of figures
Figure 1.1 Study area 3
Figure 3.1 Pre-European settlement vegetation communities 11 Figure 3.2 Location of remnant native vegetation 17
Figure 3.3 Location of threatened species and potential impact sites (Northern Expressway) 21
Figure 3.4 Location of significant weed infestations 25 Figure 3.5 Location of species of conservation significance (Port Wakefield Road Upgrade) 29
List of tables
Table 2.1 Survey information 8
Table 3.1 Indigenous flora species recorded or predicted to occur in the region and study area and their conservation status for both sections of the proposed route 18
Table 3.2 Introduced pest plant species of particular importance present in both sections of the region and study area 22
Attachments
A Native (indigenous) flora species list for Northern Expressway and Port Wakefield Road Upgrade study areas B Introduced flora species in Northern Expressway and Port Wakefield Road Upgrade area
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List of abbreviations
CEMP Construction Environmental Management Plan
DEH (Cwlth) Commonwealth Department of the Environment and Heritage DEH (SA) South Australian Department for Environment and Heritage
DTEI Department for Transport, Energy and Infrastructure dGPS differential global positioning system ha hectare
EMP Environmental Management Plan
EPBC Act Commonwealth Environment Protection and Biodiversity Conservation Act 1999
NRM Act South Australian Natural Resources Management Act 2004
NPW Act South Australian National Parks and Wildlife Act 1972 (SA) NVC Native Vegetation Council
RMS roadside marker system (to mark significant roadside remnant native vegetation) RSS roadside significant site
SEB significant environmental benefit sp. species (singular) spp species (plural) ssp. subspecies
UFBP Urban Forest Biodiversity Program
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Glossary
Word Definition aeolian relating to or caused by wind, such as a dune Adelaide Plains a relatively flat area from the Northern Adelaide Plains to the Willunga basin in the south, covering about 560km² (see also Northern Adelaide Plains) agriculture the science of producing healthy plants and animals for food and other uses alkaline having a pH greater than 7 alluvium sediment deposited by flowing water, as in a riverbed, floodplain, or delta anthropogenic caused by humans aquifer a layer of permeable rock, sand, or gravel through which groundwater flows, containing enough water to supply wells and springs biodiversity the variety of all life forms; different plants, animals and micro- organisms, the genes they contain, and the ecosystems they form part of clearance application required under the Native Vegetation Act 1991 for assessment by the Native Vegetation Council, which must contain details of the clearance, aerial photography and the location of ameliorative measures (i.e. areas set aside on which significant environmental benefit may be achieved) depauperate less than fully grown or developed; lacking or depleted in the variety of species ephemeral wetlands wetlands that temporarily hold water gypseous containing large amounts of gypsum (calcium sulphate) habitat locality or environment where a plant, animal, population or community of interest lives; each living organism has a preferred habitat with the physical surroundings having a direct bearing on its function and survival horticulture intensive cultivation of flowers, fruits, vegetables, or ornamental plants indigenous originating and living or occurring naturally in an area or environment in-stream flora plant species growing in an aquatic environment
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Word Definition introduced species an animal or plant that has been introduced to an area where it normally does not occur invasive a species introduced by human action to a location, area or region where it did not previously occur naturally (i.e. is not native), and becomes capable of establishing a breeding population in the new location without further intervention by humans, spreading widely kunkar rock formed by the evaporation of calcium carbonate mineralised water at the surface of the soil net gain actions that contribute to improving the condition of the environment and biodiversity of the region (see also significant environmental benefit) outwash plain a broad, outspread flat or gently sloping alluvial deposit of soil or rock in front of or beyond the outflow of water Peachey Belt an area in the Northern Adelaide Plains defined by a 2 km stretch of road, Peachey Road, and characteristic mallee woodland communities that were mostly cleared for primary production in the first 80 years of European settlement
Port Wakefield Road The southern section of the Northern Expressway Project between Upgrade Taylors Road and Salisbury Highway, which is proposed for minor upgrade works only
Pre-European before European settlement (1836 in South Australia) recent geological time period from the present day to 10,000 years BP region the general vicinity in which the project is located remnant a small surviving component of an original extent; includes all intact and predominantly intact indigenous vegetation communities riparian relating to the banks of a watercourse or other water body salina a salt lake samphire salt-tolerant vegetation
Significant under the Native Vegetation Act 1991 the proponent must environmental benefit demonstrate SEB (commonly through restoration projects or (SEB) donation of funds) in order for the Native Vegetation Council to grant clearance of native vegetation (see also net gain)
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Word Definition
Significant Tree (under all exotic and native trees with a trunk circumference of 2 m or Development Act greater, or in the case of trees with multiple trunks, those with 1993) trunks with a total circumference of 2 m or more and an average circumference of 625 mm or more; measurements are taken at 1 m above natural ground level stratum a layer, such as of vegetation or soil study area within 500 m either side of the centreline of the proposed route for the Northern Expressway, and generally 100 m either side of Port Wakefield Road between Taylors Road and Salisbury Highway (expanded in some areas to include all of the area 500 m from the centreline of the alignment)
other specific impact sites that may, or will, be located outside of the alignment corridor, are also part of the study area, and include areas where indirect or consequential environmental effects may occur as a result of the project subcrop rock layer present just beneath the soil surface which does not outcrop terrestrial living or found on land, as opposed to in water bodies or the atmosphere threatening process a process that threatens, or may threaten, the survival, abundance or evolutionary development of a native species or ecological community native animals or plants that originate in the region in which they are found, i.e. not introduced and naturally occurring in an area
Northern Expressway the northern area of the project from Gawler to Port Wakefield Road (near Taylors Road) component of the route
Northern Adelaide a relatively flat area covering approximately 750 km2 centred Plains 30 km north of Adelaide’s CBD, and forming part of the larger St Vincent (Sedimentary) Basin overstorey the roughly horizontal uppermost layer of mature vegetation (i.e. trees) that overtops all other layers of foliage in the understorey (e.g. mallee, river red gums) understorey the small trees, shrubs, herbs and grasses which make up the lower layers of vegetation in a vegetation community (also referred to as groundstorey) vegetation community the make-up of the vegetation according to the plant species present and the relative amount and cover of each
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xii 1 Introduction
The proposed Northern Expressway project including the Port Wakefield Road Upgrade was developed from a planning and concept design process that considered a number of options. The final configuration of the Northern Expressway proposal, its construction method, and its environmental management during construction and operation may vary from the project described, however the project constraints, design principles and standards described in the Environmental Report would remain largely the same.
1.1 Project description
The proposed Northern Expressway, and the Port Wakefield Road upgrade, will form part of the AusLink National Network, replacing the increasingly congested Main North Road thereby providing road safety and amenity benefits. The Port Wakefield Road component involves the upgrade of the existing National Network road link that connects the Northern Expressway and the Port River Expressway. The proposed Northern Expressway between Gawler to Port Wakefield Road will provide significant State and regional benefits. It is primarily aimed at improving access to Adelaide for freight transport via the Sturt Highway, including freight for export from key areas such as the Barossa Valley wine producing area and the Riverland wine and citrus producing area. Together with the Port River Expressway, it will provide a high standard link between the Sturt Highway at Gawler and the Port of Adelaide, South Australia’s main shipping port. It will maximise the opportunity for freight transport to gain access to producers, transport hubs, freight gateways and markets, achieve better delivery times and increase cost efficiency to gain a competitive edge, while improving safety significantly. It will also improve the transport link to the regions north of Adelaide, such as Gawler and the Barossa, fringe rural communities will be more accessible to business, industry, tourists and commuters.
The Northern Expressway corridor crosses the Northern Adelaide Plains on the north west edge of the Adelaide metropolitan area. The Expressway links with the Gawler Bypass, south of Redbanks Road in the north, to Port Wakefield Road, approximately 500 m north of Taylors Road in the south. Port Wakefield Road would be upgraded between this southern terminal junction with the Expressway and the Salisbury Highway/Port River Expressway intersection.
The route passes through mainly rural and horticultural land, bypassing the township of Angle Vale on its eastern side and passing north of the Royal Australian Air Force Base Edinburgh and the land with potential for an intermodal facility at Waterloo Corner.
The proposed Expressway is about 23 km long; upgrades to Port Wakefield Road extend over 12 km.
The Expressway will be constructed to rural freeway standard in a new road corridor, providing dual carriageways, grade separation of access/connecting roads and restricted road access. The horizontal alignment of the new road has been designed for a posted speed limit of 110 km/h. The road would have a wide corridor, typically about 70 m, but may vary at some locations. Interchanges are proposed at the Gawler Bypass (partial), Curtis Road (partial), Heaslip/Womma roads and at Port Wakefield Road (signalised junction).
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The Expressway will have hard shoulders along both sides for emergency vehicles and breakdowns, space for services and drainage, and a 15m wide median. The Port Wakefield Road works would involve upgrading of the existing divided road at a number of intersections along the project length, including at Waterloo Corner Road, Bolivar Road, Ryans Road, Martins Road and the Salisbury Highway, as well as changes to service roads, traffic controls and access to properties at other locations. In most locations, Port Wakefield Road will be widened along the outside edge of the road. It is proposed that the posted speed limit on Port Wakefield Road will be typically 90 kph, but may vary at certain times to better manage safe traffic operations. Landscaping treatment and potential noise management measures will be developed where required following detailed design development. The proposed route of the Expressway and upgrade of Port Wakefield Road are shown on Figure 1.1.
1.2 Topic explanation
This technical paper assesses the vegetation and flora, including constraints and impacts, associated with the Northern Expressway and Port Wakefield Road Upgrade, and the region in which the project is to be located.
It includes a review of historical accounts of the region, the literature pertaining to past and present communities, habitats and species, the results of field surveys conducted during 2005–2007. Based on the background information and reviews, areas of biological importance and conservation significance were determined for both species and areas potentially impacted by the project. The assessment culminated in a summary of the actual and potential biological environmental impacts of the project and mitigation measures available.
1.3 Legislative requirements, policies and definitions
1.3.1 National The Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) relates to the definition, protection and management of all matters of national environmental significance such as ecological communities, species and sites. It also establishes national strategies and nationally applicable threatening processes, and provides for the development of recovery, action and threat abatement plans. It is illegal to undertake an action that will have a significant adverse impact on a matter of national environmental significance.
1.3.2 State The South Australian (SA) National Parks and Wildlife Act 1972 (NPW Act), and especially Schedules 7, 8 and 9 which list threatened flora and fauna species, protects native flora and fauna and provides lists of species that are endangered, vulnerable and rare in South Australia.
The Native Vegetation Act 1991 as amended plus Regulations, was established to protect and control the clearance of South Australia’s native vegetation.
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500m investigation corridor Study area Figure 1.1 Study Area
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The Natural Resources Management Act 2004 (NRM Act) repeals the Animal and Plant Control (Agricultural Protection and Other Purposes) Act 1986 and the Soil Conservation and Land Care Act 1997 and incorporates their functional requirements. The NRM Act establishes provisions for management of the State’s natural resources, including pest plants and animals, and land and water resources. The Development Act 1993 contains provisions for requiring approval for removal of significant trees.
The Local Government Act 1999 indicates that control of public roads is vested in the local council within local government districts. Management of native vegetation is included in this Act. The State Government policy, No Species Loss A Biodiversity Strategy for South Australia 2006–2016 (Draft) is undergoing public review. While it is still draft, this is considered to be the key policy for protection of biodiversity in the State and is applicable to the project
1.3.3 Department for Transport, Energy and Infrastructure The Department for Transport, Energy and Infrastructure (DTEI) has developed a comprehensive range of environmental policy, planning and management documents which will apply to all aspects of the project. The most important documents relevant to vegetation are: Care, Control and Management of Roads by the Commissioner of Highways (Section 26 of the Highways Act 1926) Operational Instruction 20.1 Environmental Approval Procedures Operational Instruction 21.1 Vegetation Removal Policy, which includes a detailed summary of legislative requirements applicable to DTEI in relation to native vegetation, Vegetation Assessment Guidelines and Vegetation Survey Guidelines Environmental Code of Practice for Construction Land Management Guidelines Phytophthora (dieback) Control Operational Instruction 21.3 Weeds of the Metropolitan Region and Environmental Weeds List.
1.3.4 Local council Specific policies applicable to the project include the environmental and sustainability policies and specific development plans for each of the local council regions. The provisions of the Local Government Act in relation to roads and roadside area management also apply.
1.4 Sources
Botanical names and associated nomenclature accord with Barker et al. (2005) unless stated otherwise.
1.4.1 Significance criteria Significance criteria were sourced from:
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National – the EPBC Act, including criteria for threatened communities and species, threatening processes and plans adopted to manage these matters South Australia – Department for Environment and Heritage and South Australian Museum databases, NPW Act and Schedules 7, 8 and 9 Regional – Lang and Kraehenbuehl (2002, FLORLIST 2006 update) and the City of Playford, City of Salisbury, City of Port Adelaide Enfield, Light Regional Council and DTEI databases and maps of the distribution of native vegetation and communities Local – all occurrences as all remnant native plants have some value in the study area and hence are locally significant.
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2 Methods and materials
These materials and methods apply to both the Northern Expressway (between Gawler and Port Wakefield Road) and the Port Wakefield Road Upgrade (along Port Wakefield Road to the Salisbury Highway and including the stormwater treatment wetlands complex adjacent to the Salisbury Highway and Port Wakefield Road).
Data generated by a literature survey and accession of database records from South Australian and local government authorities was compiled to provide a comprehensive model of the occurrence of communities, habitats and species in historical and current times.
The search tool of the then Department of the Environment and now the Department of the Environment and Water, (Cwlth) EPBC Act was used and provided a predictive assessment of matters of national environmental significance, primarily species and habitats of communities and species of national significance. Field surveys were undertaken by KBR and DTEI personnel between October 2005 and February 2007. Discussions and consultation with local council officers and representatives included Brian Pledger and Shauna Potter (City of Salisbury), Bill Doyle and Joanna Park (City of Playford), Andrew Philpott (Light Regional Council) and Andrew Cowley (City of Port Adelaide Enfield).
A colour aerial photograph with the proposed alignment marked on it was used as the basis for the field survey. The method used in the field was to identify areas of potential biological significance using information from the databases and literature survey, and mark these onto the aerial photograph. These formed ‘target areas’ for more detailed assessment.
In addition, all accessible areas of public land within a 1 km buffer zone around the alignment’s centre- line which could be impacted as a result of the proposed development were inspected for the Northern Expressway section. Generally a 100 m buffer zone either side of Port Wakefield road was assessed for the Port Wakefield Road Upgrade section; this buffer zone was expanded in areas where larger areas of habitat were present or consequential impacts could occur.
Those areas that might contain remnant native vegetation and which were not accessible, primarily due to private land ownership, will, if practicable, be reviewed at a later stage. The major land area not reviewed in detail was the disused Smithfield Magazine (a former ammunition storage area). If this area is accessible at a later stage, it will be reviewed then and the resultant information considered in the Supplement to the Environmental Report.
The assessment method used was to slowly (<5 km/h) drive along all roads and stop the vehicle where native plants or significant weed infestations or species were present. That area was assessed in detail on foot.
The location of each site assessed was recorded on the aerial photograph and by using a Trimble differential geographic positioning system (dGPS) with data logger. Field notes were recorded for each site, especially on species composition, presence of threatened species, abundance and threats, and photographs were recorded of many sites. The location co-ordinates of remnant trees were recorded using a dGPS and each tree was assessed under the provisions of the Development Act 1993 (SA) for significant trees i.e. those with a single trunk or multiple trunk circumference of 2 m or greater measured at 1 m above the natural ground level. (This Act does not apply to the project, but DTEI’s vegetation assessment and offset requirements will apply to any areas of native vegetation and large, significant trees proposed to be removed.)
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Table 2.1 summarises the survey dates and the primary region of each assessment period.
Table 2.1 Survey information
Survey dates Northern Expressway Survey dates Port Wakefield Road Upgrade 2005 13 October Flora 2 October Flora (and fauna) 17 November Flora 6 October Flora (and fauna) 18 November Flora (and fauna) 10 October Flora 19 November Flora (and fauna) 16 October Flora 23 November Flora (and fauna) 30 November Flora (and fauna) 16 December Flora (and fauna) 17 December Flora (and fauna) 27 December Flora 2006 17 February Flora (and fauna) 21 April Flora Flora 10 October Flora 18 October Flora Flora 25 October Flora Flora 4 November Flora (and fauna) 16 November Flora (and fauna) Flora 2, 3 December Flora (and fauna) Flora 9, 10, 15 December Flora 2007 27, 30 January Flora Flora 3 February Flora Flora
Multiple visits to particular sites were used confirm seasonal variation in the flora. Herbarium collections and seed collections were made at some sites. The identity of some species was confirmed using the reference collection of South Australia’s flora in the State Herbarium of South Australia.
Some assessments were undertaken during 2005, a year of average rainfall, and some during 2006– 2007, a year with below average rainfall over winter and spring. The suboptimal conditions, as well as continual mowing of roadside areas may have resulted in some populations and/or species not being recorded.
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3 Existing conditions
3.1 Description of existing conditions within corridor
For biological matters, past conditions are as important as those currently existing for influencing the distribution of communities and species. For example, understanding the distribution of soils and past vegetation provides a ‘picture in time’ of the original native vegetation, which in turn allows for the development of a predictive model for the current occurrence of vegetation communities and species. This is equally important in assisting with revegetation concepts and developing landscape plans for particular sites.
This section discusses both past and present information relevant to the distribution of flora (and fauna).
3.1.1 Existing regional environment The vegetation communities of the region were originally the result of the interaction between physical environmental factors such as climate, topography, soil type and water. Of these, geology, landform and soils are considered to be the most important influence on distribution of communities and species.
Geology, landform and soils
There is no obvious expression of parent geology in the region and outcrop and subcrop was not recorded by Laut et al. (1977). The only geology recorded in the literature is a shallow calcrete/kunkar limestone layer present in some soil profiles, or occasionally outcropping in eroded areas.
Laut et al. (1977) indicates that the region and study area are part of the outwash plain of the Mount Lofty Range. Most of the study area is within the Northern Adelaide Plains of the Adelaide Plains geographical region with a small section of the alignment north of the Gawler River on Reeves Plain (Beecroft et al. 1981). Areas of red-brown earths and red duplex soils (Dr 2.23 or Dr 2.33 of Northcote 1960) occupy much of the southern and central sections of the site and adjacent areas. Soils are typically alkaline (sometimes calcareous), deep, relatively fertile and with excellent water holding capacity. Some are medium clays to grey-black earths (Ug 5.1), especially in low lying areas which originally contained swamps and annual wetlands.
Other areas are naturally salty, primarily along the western edge of the region (saline muds); areas of secondary salinisation associated with irrigation are also present.
Smaller sections of the central study area and associated region contain shallow calcareous silty clays with calcareous gravels and a pan layer of kunkar limestone and/or marl. The area north of the Gawler River contains a complex of soil types with areas of medium and heavy clay, alluvium, alkaline, red-brown duplex earths and widely spaced red-brown sand dunes. The latter are derived from the weathering, transport and deposition of coastal and riparian soils further inland. They are a Pleistocene aeolian dune system of deep sands, usually >4 m deep and often 20+ m high.
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Red-brown sands (Uc 5.11) and brown calcareous loams (Gc 1.12) make up the dunes, calcareous loamy earths (Gc 1.11) the interdune swales. Around drainage lines, especially the Gawler River and Little Para River and, to a lesser extent Smith Creek and Dry Creek, areas of deep, transported soils (alluvium) occur as part of the riverine floodplain, combined with the outwash plain deposits. They contain gravel, cobble and boulder beds and silty clays, as well as shallow aquifers. All deposits are associated with the past flood and meander patterns of the watercourses.
Further to the west along the coastal plain is a complex of terrestrial, freshwater and marine deposits, including small areas of saline clays plus gypseous and saline deposits in the soil profile.
The slope of the project area is low and to the west, and due to its proximity, the region would have received large amounts of runoff water as overland and channel flow from the Mount Lofty Ranges foothills before European settlement. The region was prone to flooding during most winters and following intense rainfall at other times of the year. Shallow swale drains and deeper drains, usually based on existing drainage patterns, combined with detention basins, have been constructed through the region to allow for farming and closer settlement as part of flood risk mitigation. Consequently the natural drainage system has largely been destroyed.
Current land use Horticulture and intensive agriculture and residential, retail and industrial developments characterise the past and existing land use in the study area and region. Large land users of the area include horticulture (intensive use for vegetables and flowers, rose plant production, vines and trees and hay), livestock grazing (sheep and cattle), horse studs, housing, and stormwater drainage channels. Little to nil remnant native vegetation remains in most of the region.
Several major revegetation schemes and a variety of smaller areas of revegetation have been established in the region by the local councils, the South Australian Government and other groups.
3.1.2 Pre-European settlement vegetation communities and flora Kraehenbuehl (1996) provides the only detailed historical account of the vegetation in the region before European settlement and his information includes a summary of the conditions and species present in the past and up to 1995. Turner (2001) and Daniels and Tait (2005) also provide additional historical information about some aspects of the region, primarily the Adelaide Plains. Cleland (1953), Lange (1976) and Beecroft et al. (1981) contain historical information about the Reeves Plain and adjacent region.
Additional recent reports on the vegetation, primarily areas of remnant native vegetation, are available from local councils and these are referred to in this account.
Kraehenbuehl (1996) identified four main vegetation communities (Figure 3.1) which existed before European settlement in the area of the proposed alignment:
Eucalyptus camaldulensis (river red gum) woodland and forest along the margins and floodplains of the Gawler River and little Para River also included areas of E. largiflorens (black box) woodland along the floodplain of the Gawler River.
10 Peppermint box +/- Red mallee +/- Native pine Gawler mallee and woodland River red gum Two Wells Road River red gum woodland forest and woodland +/- Black box
Angle Vale Angle Vale Road
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K in Spear-grasses, gs R o Wallaby-grasses d a a d o R th y r a o w h N ig in H a y M r Parafield Grey u b s mangrove li Airport a woodland S Mc In tyr o e Ro d a a d o R e Mixed chenopod g d shrubland ri B 0 ± 2 Modbury km
Source: Kraehenbuehl (1996) Figure 3.1 Pre-European settlement vegetation communities
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Eucalyptus porosa (mallee box) woodland and mallee across the Peachey Belt Forest, as it was referred to in the past, dominated most of the area between Penfield, Angle Vale and Virginia, with trees approximately 8–10 m in height. Understorey species were varied and species-rich in some areas. Native tussock grassland was dominated by winter growing species such as Austrodanthonia spp. (wallaby-grasses) and Austrostipa spp. (spear-grasses) and summer growing species, such as Bothriochloa macra (red-leg grass), Chloris truncata (windmill grass) and Themeda triandra (kangaroo grass), to the west and south of the Peachey Belt, which includes the suburban areas of Parafield to Paralowie. Chenopod low shrublands, dominated by Halosarcia spp. (samphires), with areas of salt tolerant sedgelands, along the western edge of the coastal plain are bordered to the west by Avicennia marina (grey mangrove) woodlands along Gulf St Vincent. In discrete freshwater sites, such as seeps, soaks and swamps, and possibly flood-out areas of watercourses, small areas of tall grassland (common reed, Phragmites australis) and sedgeland (cumbungi, Typha domingensis and salt club-rush, Bolboschoenus caldwellii) and shrubland (lignum, Muehlenbeckia florulenta) occurred in the region, although they were too small to be mapped by Kraehenbuehl (1996). These communities were found in and adjacent to watercourses and freshwater swamps.
Kraehenbuehl (1996) documents the vegetation of the Adelaide region only up to the Gawler River. The Northern Expressway Project extends north of this river and Armstrong et al. (2003), Beecroft et al. (1981), Cleland (1953) and Turner (2001) provide additional information relevant to the region of Reeves Plain (known locally in the past as the Gawler Scrub) in their mapping of the vegetation of the region. They record communities of: open to dense mallee scrubland dominated by one or up to five mallee eucalypt species, particularly Eucalyptus porosa along the northern margin of the Gawler River floodplain and red mallee (E. socialis) and peppermint box (E. odorata) further north of the floodplain growing on inter-dune swales native pine (Callitris gracilis) low open forest and woodland north of the floodplain and growing on the sand dunes. Mallee box were recognised by the early settlers as growing on areas of relatively ‘heavy soil’ which had excellent cropping characteristics and they targeted these areas for cereal production. Local areas of this vegetation were cleared soon after European settlement in the region; a larger portion of the woodlands was progressively removed to make way for mixed farming (cereal growing and livestock production) in the Peachey Belt region. With time, this clearing has almost completely destroyed these woodlands. Between 1945 and 1990 a few small areas of remnant woodland in the region around Angle Vale and Virginia were removed for market gardening.
River red gum and black box forest and woodland along the floodplain grew on some of the best quality agricultural land in South Australia, which also had the advantage of good quality underground water that was accessible by shallow bores. These areas were cleared to a similar extent as mallee box, with much of the communities removed to provide arable land, and structural timber and firewood. Small areas, including the overstorey along the river bank fringe and more occasionally on the floodplain, were left. The only relatively large, intact area of woodland is a ‘ribbon’ along the banks of the Gawler River and the Little Para River. Occasional small areas of these woodlands remain on private property and on roadsides.
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The lack of permanent water in the rivers and creeks in the region indicates that the in-stream and riparian flora was probably never extensive. However, there probably would have been an intermittent to occasional low tree to tall shrubstorey of Broughton willow (Acacia salicina) with a lower shrubstorey of lignum in many areas and a more extensive grass, sedge and forb understorey, with in-stream herblands in some sites. The native grasslands in the region provided an ideal environment for grazing of introduced stock, especially sheep. Consequently, these areas were rapidly removed within a very few years of colonisation and European settlement and subsequently used for intensive grazing, especially dairying using lucerne, and various agricultural and horticultural crops.
Brown & Root (2001) and Seaman (2002) identified small areas of ephemeral and annual wetlands associated with the outwash plains of the region. These common swamp wallaby-grass (Amphibromus nervosus) low grassland with areas of common spike-rush (Eleocharis acuta) and wiry dock (Rumex dumosus) had five-spined copperburr (Sclerolaena muricata var. villosa) on their edges and on dryland areas of the sites. The only remaining area of this community in the region, and, indeed the state, was recorded over about 25 ha on Parafield Airport land and around Bennett Road and the Mawson connector road i.e. within the wider region and south-east of the study area.
Areas of nardoo (Marsilea) fernland, usually dominated by M. drummondii, were originally present along freshwater ponds, seeps and soaks in the region, including the Bennett Road region at Parafield (Brown & Root (2001)). This community was unlikely to have been extensive in area, but it would have occurred sporadically at small sites throughout the region. In the region the community can be found on South Australian Water Corporation (SA Water) land at the Bolivar Wastewater Treatment Plant (WWTP), along the Port Wakefield Road at Virginia and at Angle Vale (Smith and Brewer 2000, R Anderson, pers. obs., 2000 to 2005). A low herbland of rosinweed (Cressa cretica)+/- round-leaved wilsonia (Wilsonia rotundifolia) +/- small- spine bindyi (Sclerolaena uniflora) occurred on low lying areas in this region, including at Parafield (Brown & Root 2001), Bolivar (Smith and Brewer 2000) and elsewhere (R Anderson, pers. obs., 2004). Based on existing occurrence, the herbland was contiguous with, but not located in, the freshwater wetlands at Parafield. It currently has a patchy distribution, although more of it remains extant than the fernland. Anderson (pers. obs.) considers that this herbland is likely to have been a component of a cottonbush ( Maireana aphylla) +/- nitre bush ( Nitraria billardieri) low shrubland that originally occurred in the region and is still at Bolivar (Smith and Brewer 2000), around Two Wells and a few other sites in the region (R Anderson, pers. obs., 2004). Five-spined copperburr shrubland was also associated with this cottonbush shrubland, but its current distribution may represent areas of a relatively unpalatable species that has not been grazed, rather than a primary distribution.
Areas of dense to open lignum shrubland were associated with low lying sites, floodplains and swamps adjacent to drainage lines, especially Dry Creek and the Little Para River, and to a lesser extent along parts of the Gawler River. Some of these were apparently mono-specific shrublands without an overstorey, while others would have formed the understorey of part of the river red gum woodland and forest. Areas of cutting grasses (Gahnia spp.) occupied these poorly drained sites but almost all of these swamps have been cleared. Until recently a few tiny remnants existed west of Salisbury Highway (around the current location of Ryans Road) and adjacent to Port Wakefield Road. The largest remnant areas can be found at Bolivar through to St Kilda.
Small areas of all these communities originally occupied the region, and probably the study area.
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3.1.3 Vegetation and flora along the Northern Expressway Kraehenbuehl (1996) indicates that all major communities originally present in the region are still represented there. However, less than 4% of the natural vegetation communities remain on all of the Adelaide Plains and remnants are usually small and often degraded. For example, in the Northern Adelaide Plains within the City of Playford and City of Salisbury less than 1% of the original area of native vegetation remains. No conservation parks or similar are located in the region. The area north of the Gawler River – Gawler Belt and Reeves Plains – contains about 6% remnant native vegetation. Within the wider region (excluding the Reeves Plain region), 216 native species were probably originally present of which 57 species are considered to be extinct; relatively recent records are available for 161 species (Kraehenbuehl 1996).
Since European settlement much of the river red gum woodland and forest and areas of black box woodland have been cleared, leaving a ‘riparian ribbon’ of overstorey vegetation along the river and a degraded understorey. By observation, these woodlands extended further south than shown by Kraehenbuehl (1996), and patches extended to about Womma Road. Occasional individuals of shrub species occur as remnants in the region as do patches of tall grasslands and sedgelands dominated by common reed, cumbungi and salt club-rush. Clearance, cropping, the impacts of grazing by stock and the invasion of pest plants and animals, have left very little of the original understorey. Woody weeds dominate the shrub and understoreys of the communities, including the in-stream areas. Remnant vegetation of the Peachey Belt, which was primarily mallee box forest and woodland, is now confined to roadsides, small reserves, cemeteries and occasional sites on private land. Individual tree and plants to small patches of species from all storeys of vegetation are uncommon to rare. According to Kraehenbuehl (1996), mallee box woodland remnants adjacent to Taylors and Robert roads at Penfield and north of Penfield Road indicate that the upper and middle strata of the woodland were originally species rich. Roadside vegetation surveys within the Virginia area by Tout-Smith and Healy (1997) recorded small areas of good quality native vegetation with high conservation status at six major locations:
Short Road, north of Womma Road the eastern side of Taylors Road, north of Womma Road Womma Road Penfield Road corner of Huxtable and Taylors roads intersection of Mill and Greyhound roads. Pastock et al. (1998) reviewed the current distribution of river red gum woodland along the Gawler River between Gawler and Wingate Road. Based on their assessment criteria, the condition of the general area of the proposed crossing point of the road is fair. They also noted areas of accelerated erosion both generally and along this reach of the river. Eight plant species of regional conservation significance were recorded along the eastern section of the river surveyed by Pastock et al. (1998). None of these species was recorded west of Wingate Road.
Bagust (2000) provided information about roadside native vegetation in the vicinity of the study area. The best quality site was the northern section of Short Road which contained mallee box woodland with individuals and small occurrences of various shrubstorey and understorey species.
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Records of remnant vegetation communities in the region, including the location of roadside significant sites (RSS) and roadside marker system (RMS) provided by DTEI and officers of local councils respectively are displayed in Figure 3.2.
The current vegetation in the region mostly consists of anthropogenic (introduced plant species (weeds) in a disturbed environment) shrubstorey and groundstorey ‘communities’, with occasional indigenous plants as individuals or small patches along roadsides, with rare, larger areas on private land and along roadsides. Little overstorey vegetation remains in the southern and central sections of the study area. Where it does, it is limited to individual, isolated trees to small copses. Areas around the Gawler River contain tall eucalypt-dominated woodland and the Reeves Plain region of plains and dunes north of the Gawler River has areas of remnant mallee scrubland-woodland and native pine woodland. There are large areas of revegetation plantings in the region, many using locally sourced species. Much of the area is dominated by introduced plants, either agricultural crops or weeds.
3.1.4 Vegetation and flora along the Port Wakefield Road Upgrade As described by Kraehenbuehl (1996) and considered in the database of the SA Biological Survey (DEH, SA), very little native vegetation and indigenous flora remain along the Port Wakefield Road.
Detailed community and species information is available only for two sites:
the SA Water land on the floodplain of the Little Para River and land along the length of this river which retain areas of remnant river red gum woodland (Smith and Brewer 2000, Berkinshaw 2004a, b) the area from Dry Creek to the water treatment wetlands and adjacent samphire shrublands around Port Wakefield Road and Salisbury Highway at the southern end of the study area (PPK Consultants 1992, Cox 1993, Brown & Root 2000, KBR 2004). Most of this section of the study area is dominated by anthropogenic areas (weeds) and areas of planted native and indigenous vegetation, such as adjacent to the Little Para River.
3.2 Northern Expressway vegetation and flora survey information
In this section, descriptions of the vegetation communities and flora species recorded in the survey area and in the surrounding region during the field assessment, are complemented by comments on the integrity and significance of the communities and sites, with particular consideration of their conservation status
3.2.1 Vegetation communities Sites in the study area and region containing relatively large amounts or regionally significant native vegetation were assessed in the field as part of the current project (Figure 3.2). Surrounding the Gawler River is a corridor of remnant river red gum +/- black box woodland over an anthropogenic understorey dominated by a range of proclaimed and environmental weeds. Native species such as common reed, cumbungi and spiny sedge are present at a few sites in the study area
15
and elsewhere along the river, and other regionally threatened native sedges and shrubs have been recorded in the region east of Wingate Road by Pastock et al. (1998). The condition of the community around the proposed crossing is rated as fair to poor.
The river red gum woodland also occurs as scattered single trees and small areas of woodland remnants on private properties and roadsides throughout the survey area and region. Remnant mallee box woodland, grassland and sedgeland areas remain throughout the survey area. All sites are small in size and many are confined to individual or small groups of trees and or understorey plants. These sites are surrounded by anthropogenic vegetation and private land used for residential and retail developments, agriculture and horticulture. The best quality areas of remnant native species on public land have been listed as RSS and RMS and the location of these sites are shown on Figure 3.2. Areas of mallee woodland and scrubland (Eucalyptus porosa, E. socialis, E. dumosa and E. odorata) and Callitris gracilis woodland-forest north of the Gawler River is reasonably intact, though limited in distribution and fragmentary (Figure 3.2). All remnant communities have a high conservation priority in the region and the state (Neagle 1995, Armstrong et al. 2003, UFBP 2006) and the sites contain a relatively high diversity of plant species and small areas of good quality fauna habitat. A number of these sites are currently being managed by local councils through the Urban Forest Biodiversity Program (UFBP), such as the vegetation in the Willaston Cemetery, along the railway corridor from the Gawler Bypass bridge to Twartz Road (Clark 2000, UFBP 2006) and Atyeo Road (UFBP 2002). Most of the areas are distant from the alignment. Small areas of sparse, native shrubland, grassland and herbland vegetation are present throughout the study area. Many of these are degraded and secondary grasslands occur i.e. areas in which native grasses have remained or colonised after vegetation clearance. Revegetation areas throughout the region represent a considerable investment in local and state resources. Most roadsides are part of a landscape and revegetation scheme, with many areas planted using local indigenous species. Broadscale revegetation sites in the region include the various UFBP and One Million Trees Program. Smaller programs include Landcare projects, such as the Roadside Revegetation Project at Lewiston, various Trees for Life Bush for Life sites and the Gawler River Restoration Plan. The importance of these works is in the use of local provenance species in order to ensure that specific biotypes are not lost and that the local biodiversity is preserved and expanded.
3.2.2 Threatened communities All of the communities originally present in the region and study area are now considered to be threatened, although none is formally listed under Commonwealth or State legislation.
Neagle (1995) considers that mallee box woodland is poorly conserved in South Australia. The river red gum woodland of seasonally inundated flats of the region is considered to be vulnerable for the state (DEH (SA) 2005).
Neagle (1995) and DEH (SA) (2005) list irongrass (Lomandra) tussock grassland and kangaroo grass+/- wallaby-grass tussock grassland as rare and endangered in South Australia. Eucalyptus odorata (peppermint box) grassy woodland has also been ranked as endangered, primarily due to the species being almost entirely confined to the state and many examples of the community declining in distribution and integrity. All three of these communities have been nominated under the EPBC Act for
16 Remnant mallee and native pine communities Gawler
Two Wells Road
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RMS 088 RMS 089 RMS 095
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Port River Expressway DTEI roadside significant site (RSS) Council roadside marker site (RMS) Figure 3.2 Location of remnant Remnant native vegetation native vegetation
17
national protection and the nominations are currently being considered by the Threatened Species Scientific Committee. Irongrass tussock grassland does not appear to have been present as a community in the region. Nonetheless, both key species of this community are present as remnant individuals and small patches in the study area and region. Larger remnants of this community occur to the east of the region, for example in foothills suburbs such as Blakeview.
3.2.3 Flora (species) A total of about 220 species were recorded in the region and study area, of which about 70 were indigenous and 150 introduced (see Attachment). Table 3.1 lists those species with a conservation rating.
Table 3.1 Indigenous flora species recorded or predicted to occur in the region and study area and their conservation status for both sections of the proposed route
Family Common name Species Rating Location
AUS SA SL NE PWU Apocynaceae sea box Alyxia buxifolia R 9 - Chenopodiaceae cotton bush Maireana aphylla V 9 9 black cottonbush Maireana decalvans E E - 9 bead glasswort Halosarcia flabelliformis V V V - - fragrant saltbush Rhagodia parabolica V 9 -
five-spine copperburr Sclerolaena muricata R 9 9 var. villosa small-spine bindyi Sclerolaena uniflora Q 9 9 Convolvulaceae rosinweed Cressa cretica V 9 9 round-leaved wilsonia Wilsonia rotundifolia V 9 9 silky wilsonia Wilsonia humilis U - 9 Cyperaceae smooth cutting-grass Gahnia filum R R - 9 Gramineae wire-grass Aristida australis R K 9 - short-crest spear- Austrostipa curticoma U - 9 grass rusty spear-grass Austrostipa eremophila U 9 9 flat-awn spear-grass Austrostipa platychaeta T 9 - barren cane-grass Eragrostis infecunda R R 9 9 umbrella grass Enteropogon acicularis Q 9 9 rigid panic Whalleya proluta R 9 - Juncaceae hoary sea-rush Juncus radula V E - 9 Leguminosae hakea wattle Acacia hakeoides K 9 - umbrella bush Acacia ligulata K 9 9 willow wattle Acacia salicina V 9 -
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Family Common name Species Rating Location
AUS SA SL NE PWU elegant wattle Acacia victoriae V 9 – Liliaceae scented matt-rush Lomandra effusa R 9 – Marsiliaceae nardoo Marsilea drummondii R 9 9 Myoporaceae weeping emu-bush Eremophila longifolia V 9 – sugarwood Myoporum platycarpum R 9 – ssp. perbellum Myrtaceae black box Eucalyptus largiflorens V 9 – mallee box Eucalyptus porosa U 9 9 red mallee Eucalyptus socialis U 9 mallee honey-myrtle Melaleuca acuminata K 9 – dryland tea-tree Melaleuca lanceolata U 9 – ssp. lanceolata Orchidaceae greencomb spider- Caladenia tensa E E E 9 – orchid pale leek-orchid Prasophyllum pallidum V V V – – Pittosporaceae native apricot Pittosporum R 9 – phylliraeoides var. microcarpa Polygonaceae lignum Muehlenbeckia R 9 9 florulenta wiry dock Rumex dumosus R R – – Santalaceae quandong Santalum acuminatum V 9 –
Aus – Australia; SA – South Australia; SL – Southern Lofty; NE – Gawler–Port Wakefield Road; PWU – Port Wakefield Road Upgrade; – not recorded. National Conservation Status according to EPBC Act 1999; E – endangered, V – vulnerable. South Australian Conservation Status codes based on Schedules of the National Parks and Wildlife Act 1972 (SA) as amended in 2000. Regional conservation status (regions defined by the State Herbarium of SA): E – endangered: rare and in danger of becoming extinct in the wild T – threatened: likely to be either endangered or vulnerable but insufficient data for more precise assessment V – vulnerable: rare and at risk from potential or long term threats that could cause the species to become endangered in the future K – uncertain: likely to be either threatened or rare but insufficient data for a more precise assessment R – rare: low overall frequency of occurrence (may be locally common with a very restricted distribution or scattered sparsely over a wider area) not currently exposed to significant or widespread threats but warrants monitoring and protective measures to prevent reduction of population size U – uncommon: less common species of interest but not rare enough to warrant special protective measures Q – not yet assessed but flagged as being of possible significance.
3.2.4 Threatened species The taxonomy and significance status used here for each species is based on Barker et al. (2005) and Lang and Kraehenbuehl (2002, FLORLIST 2006 update). Table 3.1 lists those threatened species recorded or predicted to occur in the region and study area and Figure 3.3 indicates the location of some of the most important species in the study area.
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National Three nationally threatened species are predicted to occur in the region using the search tool for matters of national environmental significance of the EPBC Act. Of these, greencomb spider-orchid (Caladenia tensa, endangered) and pale leek-orchid (Prasophyllum pallidum, vulnerable) occur in woodland and mallee communities.
Greencomb spider-orchid is present in the region relatively close to the study area with two recent records – for Willaston in 2000 and Roseworthy in 2002. Both records are from relatively intact areas of mallee and native pine community. The proposed road alignment has been subject to land clearance and intensive farming over the past 100 years, and thus does not contain suitable habitat for either species. The likelihood of either of these orchid species occurring in the survey area is very low to nil.
The vulnerable bead glasswort (Halosarcia flabelliformis) occupies coastal samphire communities, salinas and gypseous soils. Its distribution is well documented for the wider region (State Herbarium specimen database and D Fotheringham, Coast Protection Branch, DEH (SA) Feb. 2006, pers. comm.) and it is entirely confined to the areas within 1 km of the eastern coastline of Gulf St Vincent. The proposed alignment is distant from this habitat and the only areas of samphire vegetation are adjacent to Port Wakefield Road and Salisbury Highway. There is no suitable habitat for the species within the survey area and this plant species does not occur here. The species is currently being reviewed for de-listing as a species of national significance.
State Six flora species of state conservation significance (listed under Schedules of the National Parks and Wildlife Act 1972 (SA), but excluding those species considered under the EPBC Act, were recorded in the region during fieldwork and two species were located along the Northern Expressway section of the route (Section 3.3.1). Wire-grass (Aristida australis) was recorded in two small populations with a total of about 20 plants on the south side of Angle Vale Road, west of the intersection with Wingate Road (Figure 3.3). It is likely that this species is present elsewhere, but was not observed due to the dry conditions and the intensive roadside fire fuel load reduction mowing occurring in the district over late spring and summer 2006–07.
Barren cane-grass (Eragrostis infecunda) is present in the region but south of the proposed alignment. The species is present on low lying areas over clay along the western side of Greyhound Road and surrounding the Greyhound and Mill Road intersection (Figure 3.3). This plant has a conservation rating of rare in South Australia and vulnerable in the Southern Lofty Botanical Region. It has also been recorded from SA Water land at Bolivar (Section 3.3.1).
Regional Flora species with listed conservation significance for the Southern Lofty botanical region, as defined by Lang and Kraehenbuehl (2002), exclude those considered under the previous section. Their significance rating is a guide only and does not have standing under legislation:
Endangered: no species recorded. Threatened: one species, flat-awn spear-grass (Austrostipa platychaeta).
20 ay hw ig t H ur St
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21 St Kilda
Vulnerable: nine species, many recorded north of the Gawler River and several with sporadic distribution south of the Gawler River. Rare: seven species, most of which are distant from the alignment. Other conservation significance categories include uncertain (K) three species, uncommon (U) six species, and not yet assessed (Q) two species.
Many of these regionally significant species only occur north of the Gawler River, for example, in the mallee and native pine area shown on Figure 3.3.
3.2.5 Introduced and pest plant species The region, including both sections of the study area, is dominated by anthropogenic communities with many introduced and invasive plant species. Based on analysis of species lists for the council areas and past reports, over 220 introduced plant species have been recorded in the region, with about 150 weed species observed during the field assessment.
Table 3.2 lists the introduced species of particular environmental concern recorded in the study area and surrounding region based on field assessments, analysis of DTEI and State Herbarium reports and records and data provided by officers of local councils. Figure 3.4 illustrates the location of examples of infestations of the some of these weeds but does not list the location of all species or occurrences. Table 3.2 Introduced pest plant species of particular importance present in both sections of the region and study area
Family Common name Species Asparagaceae bridal creeper Asparagus asparagoides Boraginaceae salvation jane Echium plantagineum common heliotrope Heliotropium europaeum Cactaceae prickly pear Opuntia spp. (x 4 ) Compositae creeping knapweed Acroptilon repens skeleton weed Chondrilla juncea boneseed Chrysanthemoides monilifera spear thistle Cirsium vulgare artichoke thistle Cynara cardunculus gazania Gazania spp. (especially G. rigens and cultivars) Calomba daisy Oncosiphon suffruticosum golden pallenis Pallenis spinosa African daisy Senecio pterophorus variegated thistle Silybum marianum Bathurst burr Xanthium spinosum Noogoora burr Xanthium strumarium Convolvulaceae field bindweed Convolvulus arvensis Cyperaceae drain sedge Cyperus eragrostis nut-grass sedge Cyperus rotundus
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Family Common name Species Cruciferae Lincoln weed Diplotaxis tenuifolia musk weed Myagrum perfoliatum Dipsacaceae scabious Scabiosa atropurpurea Euphorbiaceae castor oil plant Ricinus communis Gramineae bamboo Arundo donax innocent weed Cenchrus spp. especially C. longispinus African lovegrass Eragrostis curvula Coolatai grass Hyarrhenia hirta kikuyu Pennisetum clandestinum African feathergrass Pennisetum macrourum feathertop grass Pennisetum villosum phalaris Phalaris aquatica lesser canary-grass Phalaris minor rice millet Piptatherum miliaceum Guttiferae St John's wort Hypericum perforatum Iridaceae one-leaf cape-tulip Homeria flaccida Labiatae horehound Marrubium vulgare wild sage Salvia verbenaca Liliaceae three-cornered garlic Allium triquetrum crow garlic Allium vineale onion weed Asphodelus fistulosus Oleaceae desert ash Fraxinus angustifolia olive Olea europaea Oxalidaceae sour-sob Oxalis pes-caprae Polygonaceae spiny emex, three-cornered jack Emex australis Resedaceae cut-leaf mignonette Reseda lutea Rosaceae dog rose Rosa canina Scrophulariaceae hairy toadflax Kickxia elatine Solanaceae African boxthorn Lycium ferocissimum silverleaf nightshade Solanum elaeagnifolium Umbelliferae fennel Foeniculum vulgare Zygophyllaceae caltrop Tribulus terrestris
Natural Resource Management Act 2004 and DTEI Environmental Weeds.
These 51 weed species have agricultural impacts and/or adverse effects on remnant native vegetation and native fauna. Many of these species are represented by a sparse or relatively limited distribution, while others are widespread. All are important from conservation and agricultural impacts.
3.2.6 Threatening processes and plant pathogens One national, key threatening process listed under the EPBC Act has been recorded in the region namely “Dieback caused by the root-rot fungus (Phytophthora cinnamomi)”. A threat abatement plan has been established for this process (DEH (Cwlth) 2001). The study area is considered to be a moderate risk site for this disease (DTEI Operational Instruction 21.3).
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Mundulla Yellows has been recorded in the study area and region on various host trees and a number of trees with yellow foliage, aberrant growths on foliage and large amounts of canopy die-back were noted. It is possible that these trees—mostly isolated mallee box—are being adversely impacted by the use of agricultural chemicals and fertilisers in adjacent cultivated areas, such as through ‘spray drift’.
Based on observation, a number of other plant pathogens and diseases associated with specific agricultural and horticultural crops are present in the region.
3.3 Port Wakefield Road Upgrade vegetation and flora survey information
The portion of the project from the intersection of Taylors Road and Port Wakefield Road is primarily located in and adjacent to disturbed areas, especially residential and retail zones, and anthropogenic vegetation communities. Consequently, for most of the route there is little or nil indigenous vegetation.
3.3.1 Vegetation communities The region originally contained vegetation communities and flora assemblages both similar and different to the northern portion of the survey area (Figure 3.1). However, very few sites have remnant native vegetation along Port Wakefield Road and the species diversity of these sites is much less than for the northern section of the route.
Along the Little Para River and its floodplain remnant river red gum woodland occurs over an anthropogenic understorey. Common reed, cumbungi and spiny sedge are present in the watercourse corridor, along with a wide range of weed species. The river red gum woodland is the only remnant overstorey community in this section of the study area (Figure 3.1).
Remnant mature significant trees (as defined under the Development Act) are located in SA Water land, which still maintains the semblance of open river red gum woodland. In the section of Port Wakefield Road on the eastern side of the road north of the BP service station and south to Victoria Drive, over 60 individual large trees remain. The majority of these trees are remnant, indigenous river red gums associated with the floodplain and banks of the Little Para River. Sugar gums (Eucalyptus cladocalyx), many now mature trees, have been planted along the northern side of the Little Para River. These native species are not indigenous to the study area.
Most of these trees are located along the edge of the road alignment and some are unlikely to be impacted by the roadworks. However, all have been assessed in case the proposed works affect their root zone or some of the trees become a road safety hazard as a result of the proposed roadworks.
Eight other trees along the northern section of the centre median between Hodgson Road and Bolivar Road are significant trees, previously assessed in the Transport SA Vegetation Survey No. 2005/089 (Transport SA 2005). Two further significant trees are located north of the intersection of Daniel Road and Port Wakefield Road (western side).
There are few areas or individual plants of remnant indigenous native understorey vegetation associated with this part of the road corridor. Two occurrences of lignum and occasional plants of Austrodanthonia spp., Balcarra grass (Austrostipa nitida), rough spear-grass (A. scabra), berry
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saltbush (Atriplex semibaccata) and plants of five-spined copperburr in three populations were recorded. The only remnant mallee box woodland and scrubland areas recorded were on SA Water land at Bolivar and at Kings Road, Salisbury (Smith and Brewer 2000).
Remnant native shrubland was present only in SA Water land at Bolivar (Berkinshaw 2004a, b), adjacent to Port Wakefield Road and the southern section of the route adjacent to the Port Wakefield Road and Salisbury Highway as:
lignum open shrubland on SA Water land at Bolivar and on parts of the Little Para River corridor cottonbush +/ - nitre bush low shrubland at Bolivar, on Cheetham-owned land (the salt fields), DTEI-owned land and in water treatment wetland areas grey samphire (Halosarcia halocnemoides) and black-seeded samphire (H. pergranulata) low shrubland. Small areas of remnant native tussock grassland are present but the species and diversity recorded indicated that they are degraded examples of secondary grasslands only. All recorded sites included Balcarra grass or rough spear-grass, native ‘colonising’ species able to grow successfully in roadside areas. Tall grassland of common reed is present along the Little Para River, in constructed stormwater detention basins and water treatment wetlands on the floodplain and in open drains in the region.
Remnants of a complex of sedgelands originally found in the region remain. Cumbungi also occurs in sites similar to that of the common reed, although it tolerates higher salinity conditions and occupies a number of drains, wetlands and other sites which retain water. It forms an important component of the constructed wetlands at the southern end of the route. Salt club-rush has a similar distribution to cumbungi. Smooth cutting-grass (Gahnia filum) is present on SA Water land at Bolivar, at St Kilda and at Ryans Road, Salisbury. It has also been planted in the southern wetlands complex including the Greenfields to Barker Inlet wetland sites. Areas of Juncus spp. especially finger rush (J. subsecundus), pale rush (J. pallidus) and sea rush (J. kraussii) have also been planted in the wetlands.
Planted dryland vegetation is a common feature of the region. The City of Salisbury, the City of Port Adelaide Enfield and DTEI have been responsible for large areas of planted native vegetation in the study area and region since the 1970s (PPK Consultants 1992). Most plantations are native and some areas have been propagated from locally indigenous sources. The swamp oaks (Casuarina glauca) planted between Salisbury Highway and Dry Creek (primarily on the western side of the Port Wakefield Road) are large but not sufficiently so to accord with the definition of significant trees.
Stormwater treatment wetlands are the major and most significant repositories for flora in this area. Many incorporate existing areas of degraded native coastal vegetation into the wetlands and combine them with planted areas of species native to the region, which has improved the condition of the indigenous communities. The resulting complex of vegetation types is of conservation value for flora and habitat for fauna.
3.3.2 Threatened communities All remnant native vegetation communities in the region and study area are of conservation significance. The most intact and important areas are present on SA Water land at Bolivar. A small
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portion of the river red gum community immediately adjacent to Port Wakefield Road is the only area of a remnant community potentially affected by the proposal.
3.3.3 Flora (species) The attachment to this technical paper lists all plant species recorded in the Port Wakefield Road corridor. Only 23 indigenous species were recorded along Port Wakefield Road, generally as isolated individual to small groups of plants only. The greatest diversity of species is found on SA Water land at Bolivar and elsewhere in the region, such as in the coastal saltmarsh communities west of the proposed works areas and the wetlands at the southern end of the project area.
3.3.4 Threatened species National The endangered greencomb spider-orchid and vulnerable pale leek-orchid are predicted to occur in the region by the search tool of the EPBC Act (see Section 3.2.4). However, both species only occur in relatively intact woodland and mallee communities, and past intensive land clearance in the area has removed suitable habitat for these species. The likelihood of either of these orchid species occurring in the study area is nil.
The bead glasswort (vulnerable) occurs in coastal samphire communities, salinas and gypseous soils which are distant from the proposed alignment. Areas of samphire vegetation adjacent to Port Wakefield Road may be affected by construction but the distribution of this species is entirely confined to the areas within 1 km of the coastline of Gulf St Vincent. All potentially suitable habitat for the species within the study area adjacent to the Salisbury Highway, on DTEI-owned land, Cheetham- owned land and along Dry Creek was searched thoroughly at the best time of the year in which to see the species. This plant species does not currently occur in the study area.
State The endangered black cottonbush (Maireana decalvans), vulnerable hoary sea-rush (Juncus radula), and rare barren cane-grass and smooth cutting-grass, occupy similar areas of habitat at Bolivar on SA Water land west of the Port Wakefield Road. Wiry dock was not recorded in the study area or region, but it is present in the wider region well to the east of the Salisbury Highway.
Regional Rosinweed (Cressa cretica), cottonbush and round-leaved wilsonia (all regionally vulnerable) and nardoo (regionally rare) occur on SA Water land at Bolivar with a small population of rosinweed recorded in the White’s Road drain. All of these sites are west of the Port Wakefield Road and will not be affected by the proposal.
Lignum (regionally rare) is associated with the Little Para River and its floodplain. It occurs as isolated clumps or a few bushes along Port Wakefield Road and is more extensively distributed on SA Water land and in patches along the watercourse. Five-spined copperburr occurs in similar low-lying locations adjacent to Port Wakefield road at a number of sites, especially around Dry Creek. It is possible that other regionally threatened species could occur here also.
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All of the other five species with a lesser regional significance rating (considered in Table 3.1) were not recorded in the study area during the field assessments. Figure 3.5 illustrates the location of some of the plant species of particular conservation significance adjacent to Port Wakefield Road.
3.3.5 Introduced and pest plant species The understorey in the region, including along and adjacent to the proposed road alignment is dominated by anthropogenic understorey with many introduced and invasive plant species (120 species were recorded for this section of the study area). Some areas include shrub and overstorey weed species, especially in and adjacent to the Little Para River. Table 3.2 lists the most important introduced species recorded in the study area and surrounding region. Figure 3.4 illustrates some of the locations of weed species infestations of particular ecological and agricultural concern.
The attachment to this technical paper includes a list of all introduced species recorded in and adjacent to the proposed route.
All proclaimed and environmental weed species present in the region are of concern since the large scale earthworks of the project will, without suitable management actions, spread existing weed species and introduce new weed species to the study area. Key, high risk species groups are:
perennials such as silverleaf nightshade and field bindweed which are widely distributed throughout the region, spread from seeds and cuttings, especially root cuttings, and are tolerant of some herbicides with some populations developing herbicide resistance limited life perennial and annual species such as Lincoln weed, cut-leaf mignonette and salvation jane. Other species, such as bridal creeper, prickly pear and other cactus species, Cape tulip and St John’s wort, currently present limited problems due to their patchy occurrence. In addition, some species, such as Coolatai grass and Calomba daisy, are currently not present or are rare in the region.
3.3.6 Threatening processes and plant pathogens One national, key threatening process listed under the EPBC Act has been recorded in the region namely ‘Dieback caused by the root-rot fungus (Phytophthora cinnamomi)’. A threat abatement plan has been established for this process (DEH (Cwlth) 2001). The study area is considered to be a moderate risk site for this disease (DTEI Operational Instruction 21.3).
Mundulla Yellows has been recorded in the study area and region on various host trees and a number of trees with yellow foliage and large amounts of canopy die-back were noted adjacent to Port Wakefield Road.
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3.4 Summary of existing conditions
Northern Expressway The native vegetation communities and flora of this section of the study area are depauperate and degraded. The area is best characterised by the lack of native vegetation and the large number and diversity of pest plants. However, there are a number of small remnant areas of native vegetation, mostly along roadsides, some of which are good quality i.e. with relatively large native species diversity, lower infestations of weeds and/or threatened species present. The uniqueness of these areas gives them significance from a state, regional and local ecological perspective. In many cases, these areas represent the last vestiges of what was originally a widespread community or distribution of species. Most of the best quality and larger size remnants are located well away from the impact corridor.
Port Wakefield Road Upgrade These areas are mostly degraded with nil or few areas of remnant native vegetation communities and species. The exception is the SA Water land at Bolivar, which contains an assemblage of communities and species that are almost unique in the region. This is primarily due to its location in the floodplain of the Little Para River and the coastal fringe. These better quality and larger size remnants are located well away from the impact corridor and will not be affected by the proposal. The combined agricultural, retail and urban character of the region dominates the vegetation and introduced and pest plant species dominate most of the alignment along Port Wakefield Road.
Small areas of river red gum woodland and the associated floodplain and small, constructed wetlands of the Little Para River and the roadside edges of parts of Dry Creek and the Greenfields wetlands are the only areas which may be adversely affected by the proposal.
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4 Effects of the project upon existing conditions
The project area is a highly disturbed environment with the major land use being agriculture and horticulture.
The likely and potential environmental impacts of the proposed corridor alignment on both native vegetation communities and species are mostly low with some actual high impacts around the following site:
Gawler River: the extent of impacts will largely depend on the construction methodology chosen during the planning and design phase. An environmentally sensitive construction approach is required to ensure that the construction ‘footprint’ left in this area is minimal. Removal of trees and small areas of native understorey species along the Gawler River will be required as part of this project. Revegetation works in this region will be required to reconstruct the habitat areas affected by this project. There is also the potential for positive outcomes; the river bed and its banks are densely infested with weeds such as African boxthorn, castor oil plant, Noogoora burr, fennel, prickly pear and olive, which are proclaimed or major environmental weeds in South Australia. Bridal creeper, a weed of national significance (WONS) occurs east of the proposed crossing and, by observation, is slowly spreading downstream. Weed management works in the impact zone of the project area could provide an environmental benefit to the Gawler River but would only be effective if a combined management program with local councils and landholders targeted infestations along the whole length of this river.
Potential impact areas There are eight other sites (discussed in order from north to south, Figure 3.3) where the project may have an adverse effect on small areas of native vegetation:
the section of the Gawler to Burra railway corridor under the Gawler Bypass and the adjacent section of the Adelaide Soaring Club Hillier Road Angle Vale Road and Bain Road vicinity Petherton Road Argent Road Womma Road railway easement (eastern side of Taylors Road) Stanley Road. Most of these sites contain areas of native tussock grassland.
Weeds Throughout the study area there is a wide range of annual and perennial weed species which could be spread through the region by the movement of soil and vehicles. Without suitable and stringent
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management actions weed species will be transported throughout the construction sites and into adjacent areas. Silverleaf nightshade (Solanum elaeagnifolium) is a perennial that is widespread along most roadsides and in many areas of cultivated land. It is of particular concern since it can spread by stem and root cuttings and seeds. Control of this species before and after earthworks will be required, both in the alignment and other work areas.
The remainder of the project area is likely to experience minimal environmental impacts given the disturbed nature of the region. Further habitat fragmentation from both a flora and fauna perspective is likely with the clearance of some areas of vegetation. Given the already degraded nature of the environment it is unlikely to seriously impact on flora and fauna habitat of the region.
4.1 Environmental management
4.1.1 Principles adopted to minimise effects The Environmental Management Plan (EMP) will provide general measures for all stages of the project aimed at avoiding or minimising adverse environmental impacts, usually through specific mitigation measures, and providing for the development and implementation of positive impacts.
The Construction Environmental Management Plan (CEMP) will include the detailed requirements that the contractor undertaking the works must address and the various methods and prescriptions through which the requirements will be fulfilled.
Specific performance criteria will be established. DTEI has established environmental policies and management requirements for large and similarly complex projects (see Section 1.3.3). It has the trained and experienced staff and recent experience of environmental requirements for large projects in the region, notably the Port River Expressway. These will be applied to the current proposal.
The key issues, impacts and mitigation include planning and design, construction and operation.
4.1.2 Measures to minimise effects during planning and design The planning and design phase for the project started with the field assessments over 2005 to 2007. As far as practicable, these have identified areas of remnant native vegetation and areas of native vegetation planted by local councils and others, and the location of these areas has been recorded by dGPS, in a database and mapped.
As far as possible, species in all sections of the study area have been identified accurately to species or infra-specific status, although there have been a few areas for which species identification has not been completed (due to the drought conditions during spring and summer 2006).
This identification process, of both areas and species, has been confirmed by independent review of existing databases and sites provided by environmental officers of the local council areas and state and Australian government information and databases. This has been the first key management action i.e. to inform the project of the areas and individual plants of important community and flora remnants and to validate the occurrence by checking and consultation.
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The map of these areas, Figure 3.4 in this report, is also a ‘work in progress’. Both of these information sources form the detailed basis of recorded areas of native vegetation that will not be impacted (as a result of being distant from the construction area) and other sites that must not be impacted (which are in or adjacent to the Northern Expressway route).
Ongoing site survey will continue over summer to assess if areas of winter dormant plants, such as red-leg grass and garland lily, are present.
There is a commitment to ensuring that local flora only is used in the landscape design and revegetation planting of the Northern Expressway and Port Wakefield Road Upgrade corridor. All storeys of native vegetation will be used and the placement of these species in the landscape will, as far as practicable, accord with that which would have originally been present before 1836.
Seeds of over 30 species have been collected from known sources and sites. Different biotypes from the same species within the study area and region have also been collected.
Cuttings of those species which are difficult to propagate from seeds will be taken and plants set and grown on at a later stage. Timing of this activity will not be immediate, but will coincide with the need to establish a known quantity of plants in a particular location. The amount of seeds of each species (for direct seeding) and the numbers of plants required as tubestock (seedlings and struck cuttings) will be determined after the exact areas with particular terrain and soil characteristics are known i.e. at the detailed design stage.
As currently planned, the Northern Expressway and Port Wakefield Road Upgrade corridor offers a small degree of flexibility should a nationally threatened or state threatened species be found at some future stage. However, the risk of this occurring is considered to be very low.
Weeds Most of the roadsides and many of the open areas through which the route passes are weed infested. About 220 species of introduced plants have been recorded in the region. Of these, about 51 species are of particular concern due to their impacts on agriculture and remnant native vegetation and these species are considered in Table 3.2. Examples of these species are discussed below.
Coolatai grass is present within the region, with one clump of the species removed during the current survey in November 2006 from the south side of Angle Vale Road, 1 km west of Wingate Road intersection with Angle Vale Road. Two small infestations have been previously recorded in the City of Playford in Munno Para and Munno Para West (see Figure 3.4). The main infestations of this species are south and east of the study area.
Calomba daisy was recorded along the Two Wells to Gawler Road and the edge of the Port Wakefield Road to the Salisbury Highway (Figure 3.4).
Other species of potential concern include prickly pear and rope cactus, African boxthorn, St John’s wort, Bathurst burr and Noogoora burr, olive tree, castor oil tree, innocent weed and caltrop.
Individual sites with known or potential adverse impacts The small area of river red gum woodland (about eight or nine mature trees) proposed to be removed at the Gawler River cannot be avoided. However, following removal these trees will be used as fauna habitat within the landscape and an effort will be made to start a rehabilitation process in the river by removing the proclaimed and environmental weeds that occupy most of the corridor. Potential
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accelerated erosion hazards resulting from tree removal and destabilisation of the bank will be managed.
4.1.3 Measures to minimise effects during construction The key issues for construction are as follows:
Immediately before construction, the whole area of all surveyed construction sites will be surveyed on foot. Areas of native vegetation present will be assessed. If these are common species, such as the native colonising species represented by short-leaf bluebush or spear-grasses, then no addition approvals or mitigation actions will be undertaken. If there are species that are unusual or threatened, even isolated plants or small clumps, then the species will be protected by collection, either of the plants, followed by transplanting into a secure area, or of propagating material (seeds or cuttings). Before construction, contractors will be formally briefed about the importance of native vegetation through an induction briefing. Each individual contractor and subcontractor will verify agreement by attendance at this briefing and by signature to an agreed Code of Practice. An environmental officer from DTEI and an equivalent person from the construction contractor will be responsible for ensuring compliance; if compliance is not followed the officers will establish remedial requirements, and, if necessary, contract penalties. The key matter will be to avoid all areas of native vegetation marked on management maps and in the field.
Native vegetation will not be cleared in most areas because none is present along the proposed route. Before small areas of native vegetation are removed, all approvals will be obtained from all relevant groups. Where required, formal approval will be obtained from the Native Vegetation Council (NVC) through the submission of a vegetation clearance application using the approval process currently in place between the NVC and DTEI. Significant environmental benefit (SEB) and net gain requirements will apply to the project through DTEI’s vegetation clearance requirements. It will assess the trees and other native vegetation affected by the project along the Gawler River in consultation with the NVC. Ongoing liaison with local council and state government officers will be maintained during construction. This will include inspection and agreement as to which areas should be planted and established.
4.1.4 Measures to minimise effects during post-construction Once construction has been completed then a management and maintenance plan will be established for the Expressway. From a biological perspective, this will include management requirements for the revegetation areas, such as watering and replacement of plantings and maintenance of all areas. Local councils would be expected to be involved in these activities.
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5 Conclusions
Almost total clearance of native vegetation in the region and the study area, has left relatively few native vegetation and flora constraints to the alignment of the Northern Expressway and Port Wakefield Road Upgrade. However, the remnant areas and species of native vegetation in the region are thus extremely valuable, both intrinsically and as examples of the past biodiversity of the region.
5.1 Northern Expressway
Most of the route passes through cleared land used for agriculture with little or no native vegetation. Field assessment of the region and the study area was combined with review of databases and consultation with environmental planners and officers representing the South Australian Government and local councils. There are small to tiny remnant areas of the six vegetation communities in the region considered to have been present before European settlement. The best quality sites are listed as RSS or RMS. Nine potential sites in the study area contain remnant native vegetation that may be impacted by the proposal. Of these, only the crossing of the Gawler River will result in clearance of remnant, mature river red gum trees. The other sites contain small areas of remnant grassland or the occasional tree or tall shrub. Native grasslands along Bain Road and Argent Road could be impacted. These areas contain several species with a listed conservation rating for the Southern Lofty botanical region.
Two other important areas of native vegetation are located north and south of the study area, but will not be impacted by the proposal. Most potential impacts and mitigation measures of the project are related to ‘fine tuning’ the position of the alignment so as to avoid the small areas of native vegetation once the final, pegged centreline is known. If avoidance is not practicable, then the native flora remnants will be actively managed by various means, including removing and transplanting plants, and collecting seeds or cuttings, followed by propagation and replanting as part of the landscape rehabilitation works.
All areas of remnant native vegetation in this region are of nature conservation value due to the small areas remaining. All areas adjacent to the construction sites will also require protection wherever practicable. Collection of propagating material from native plant species has begun and will continue to ensure that as many species and biotypes as possible are represented in the collections used for future landscaping and revegetation.
One section of the study area (the Smithfield Magazine area) has not been assessed, because of weather, time and land access constraints over 2005–06. A cursory inspection over the fences and discussions with local council officers, indicate that little native vegetation is present. Nonetheless, the site requires a detailed assessment to confirm its status. All of the study area will be reviewed during summer 2006–07 in order to assess the presence of summer growing plants.
Once the exact route of the road within the study area is determined, then it will be further surveyed to allow for identification of vegetation to be removed and the improvement of mitigation measures within the final corridor.
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With over 220 species of introduced plants recorded in the region, the proper management of both winter and summer growing weeds will be a major issue for the project. Without adequate and suitable planning and controls this will be a major adverse impact of the project. Mitigation measures will include control of infestations in construction areas, management of the inadvertent transport of weeds within the construction corridor as part of the earthworks, and the reduced potential to introduce new weed species into the study area and region as a result of the project.
Species such as bridal creeper, St John’s wort, silverleaf nightshade, African boxthorn, Noogoora burr, innocent weed and caltrop are examples of proclaimed and environmental weed species that must be controlled during all stages of the project. Species such as Coolatai grass and Calomba daisy must not be introduced into new areas or spread through the construction corridor or adjacent areas as a result of the proposal. Areas of planted native vegetation will be removed by the project. They have yet to be assessed in detail under DTEI’s vegetation survey and assessment requirements. Following assessment, suitable compensation plantings will be established in consultation with local council authorities. No areas of Phytophthora cinnamomi (die-back fungus, cinnamon fungus) or Mundulla Yellows were recorded. However, many of the mallee box trees appear to have aberrant plant growths and canopy die-back, possibly as a result of exposure to agricultural chemicals. All information indicates that the risk of causing a major or significant impact to vegetation and flora within the study area, including the section which has not be subject to detailed scrutiny, is low to negligible.
5.1.1 Environment Protection and Biodiversity Conservation Act None of the native vegetation communities or species listed under the EPBC Act as potentially present in the region occur within the study area. One species, greencomb spider-orchid, occurs in the region, but its two populations are several kilometres from the study area and will not be impacted by the proposal.
5.1.2 National Parks and Wildlife Act Wire-grass, which is listed as rare under Schedule 9 of the NPW Act occurs as a small population along Angle Vale Road. It appears that the alignment will be west of these populations and will not impact on this species.
5.1.3 Development Act Significant trees along the Gawler River proposed for removal will be assessed under the Native Vegetation Act. Development approval will be obtained for any significant trees requiring removal.
5.1.4 Native Vegetation Act This Act, as amended and including its Regulations, is applicable to all areas of native vegetation on and north of the Gawler River. DTEI has developed a suite of methods to assess in detail areas of vegetation proposed for removal, plus suitable off-set measures to ensure that SEB requirements
36
under the Act are met. These methods and measures have been developed in consultation with the NVC which fully endorses them.
5.1.5 Other species of conservation significance In the region, 22 recorded plant species have listed conservation significance for the Southern Lofty botanical region. Several populations of three species may be directly impacted by the project, subject to the position of the final alignment. If they are to be disturbed, then appropriate mitigation measures will be established to safeguard these populations.
5.2 Port Wakefield Road Upgrade
The Port Wakefield Road Upgrade route passes through a disturbed and degraded corridor with relatively few native vegetation and flora values, even less than the Northern Expressway route. Few areas of native plants are present; most roadside corridors are weed-infested or contain areas of planted native vegetation.
Four sites with important native vegetation community or flora values are:
the SA Water land area on the Little Para River floodplain at Bolivar west of Port Wakefield Road the corridor of river red gum woodland and occasional remnant tree of this species along the Little Para River and adjacent sections of the floodplain, but not including SA Water land the Greenfields and Barker Inlet water treatment wetlands adjacent to Port Wakefield Road and Salisbury Highway including Dry Creek (eastern side) an area of DTEI-owned land with samphire shrubland on the western side of Salisbury Highway. Of these, the most important is the SA Water land, which contains relatively large remnants of threatened vegetation communities and species, including a number of species of significance under South Australian legislation. This land area will not be impacted by the upgrade of Port Wakefield Road.
Based on field assessments and literature surveys, the area of remnant mature river red gum woodland associated with the Little Para River floodplain will be impacted. Up to ten mature, remnant river red gums will be removed from the central median area and roadsides from Bolivar Road south to the Little Para River crossing. Mature, planted sugar gums will also be removed from this area.
Areas of the wetlands and remnant samphire shrubland are unlikely to be adversely impacted. In these areas, the vegetation proposed to be cleared along the edge of the road is degraded and weed infested.
Management of weeds will be a major issue for the project. This includes management of the inadvertent transport of weeds within the construction corridor and the potential to introduce new weed species into the study area and region.
Species such as silverleaf nightshade, artichoke thistle and caltrop are examples of proclaimed and environmental weed species that must be controlled during all stages of the project. Species such as
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Coolatai grass, Johnson grass and Calomba daisy must not be introduced or spread throughout the construction corridor or adjacent areas. No areas of Phytophthora cinnamomi (die-back fungus, cinnamon fungus) or Mundulla Yellows were recorded, although a number of sites of this yellows disease have been previously recorded along Port Wakefield Road. All available information indicates that the risk of causing a major adverse impact to native vegetation and flora within the study area is nil (for most of the route) and low for small sections adjacent to or in areas of native vegetation. These risks will be adequately managed using DTEI’s stringent environmental policy, planning and management requirements.
5.2.1 Environment Protection and Biodiversity Conservation Act None of the native vegetation communities or species listed under the EPBC Act as potentially present in the region was recorded within the study area. Bead glasswort was not recorded and is considered very unlikely to be present.
5.2.2 National Parks and Wildlife Act No species listed under Schedules of the NPW Act were recorded along Port Wakefield Road, although a number of species are present on SA Water land at Bolivar.
5.2.3 Development Act Development approval will be obtained for any significant trees requiring removal.
5.2.4 Native Vegetation Act This Act is only applicable to all areas of native vegetation on the area of land owned by DTEI adjacent to the Salisbury Highway. It is unlikely that this area will be impacted by the proposal. If an impact is unavoidable, then it will be subject to an application to the NVC.
5.2.5 Other species of conservation significance Fifteen plant species in this section of the region and study area have a listed conservation significance for the Southern Lofty botanical region, most at Bolivar on SA Water-owned land, which will not be affected. Isolated plants of lignum north of the Little Para River (rare in the Southern Lofty botanical region) will be impacted and a few plants of five-spined copperburr at two sites may be affected. Appropriate mitigation measures (removal and transplanting and collection of propagating material) will be established to safeguard these species.
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6 References
Armstrong DM, Croft SJ and Foulkes JN. 2003. A biological survey of the Southern Mount Lofty Ranges, South Australia, 2000–2001. Department for Environment and Heritage, Adelaide. Bagust PA. 2000. Roadside native vegetation surveys—Mid Western Plains. City of Playford.
Barker WR, Barker RM, Jessop JP and Vonow HP (eds). 2005. Census of South Australian vascular plants. 5th Edition. Journal of the Adelaide Botanic Gardens, Supplement 1. Beecroft AS, Hodges V, Sullivan PL and Wilson AM. 1981. Field studies in biogeography: 2. Reeves Plains. Department of Geography,The University of Adelaide.
Berkinshaw T. 2004a. Mangroves to mallee multi-site management plan for the Northern Adelaide Coastal Plains. Urban Forest Biodiversity Program, Department of Defence, SA Water, United Water, City of Playford and City of Salisbury.
Berkinshaw T. 2004b. Scoping report for the management of Bolivar Wastewater Treatment Works. Urban Forest One Million Trees Program, SA Water and United Water.
Black JM. 1909. The naturalised flora of South Australia. Hussey & Gillingham, Adelaide.
Brown & Root Services Asia Pacific Pty Ltd. 2000. Port River Expressway environmental report. Adelaide: Transport SA.
Brown & Root Services Asia Pacific Pty Ltd. 2001. Ephemeral wetland modified vegetation survey, Maxwell Road extension, Parafield Airport (Vegetation Survey No. 2001/073). Report prepared for Transport SA, Adelaide.
Clark PD. 2000. Gawler–Burra rail reserve vegetation drive-by survey 24. Unpublished report prepared for Transport SA, Adelaide. Cleland JB. 1953. Excursion to Old Sand Dunes between Gawler, Two Wells and Mallala. South Australian Naturalist, 28(2), 24–26.
Cox JB. 1993. Greenfields wetlands—water levels, salinity, flora and fauna. City of Salisbury, Salisbury.
Daniels CB and Tait CJ (eds). 2005. Adelaide Nature of a City The ecology of a dynamic city 1836 to 2036. BioCity: Centre for Urban Habitats, The University of Adelaide.
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Attachment A
Native (indigenous) flora species list for Northern Expressway and Port Wakefield Road Upgrade study areas
Native (indigenous) flora species list for Northern Expressway and Port Wakefield Road Upgrade study areas
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Aizoaceae Karkalla Carpobrotus rossii 9 Round-leaved pigface Disphyma crassifolium ssp. 9 clavellatum Apocynaceae Sea box Alyxia buxifolia 9 Chenopodiaceae Marsh saltbush Atriplex paludosa ssp. 9 cordata Berry saltbush Atriplex semibaccata 9 9 Lagoon saltbush Atriplex stipitata 9 Lagoon saltbush Atriplex suberecta 9 9 Climbing saltbush Einadia nutans ssp. nutans 9 9 Ruby saltbush Enchylaena tomentosa 9 9 Bead glasswort Halosarcia flabelliformis Grey samphire Halosarcia halocnemoides 9 var. halocnemoides Black-seeded samphire Halosarcia pergranulata 9 var. pergranulata Cottonbush Maireana aphylla 9 9 Short-leaf bluebush Maireana brevifolia 9 9 Black cottonbush Maireana decalvans 9 Wingless fissure-plant Maireana enchylaenoides 9 Sea-berry saltbush Rhagodia candolleana 9 Fragrant saltbush Rhagodia parabolica 9 Five-spine copperburr Sclerolaena muricata var. 9 9 villosa Small-spine bidyi Sclerolaena uniflora 9 9 Shrubby samphire Sclerostegia arbuscula 9 Austral seablite Suaeda australis 9 Convolvulaceae Australian bindweed Convolvulus erubescens 9 9 Grassy bindweed Convolvulus remotus 9 Rosinweed Cressa cretica 9 9 Round-leaved wilsonia Wilsonia rotundifolia 9 9 Silky wilsonia Wilsonia humilis 9 Compositae Variable groundsel Senecio lautus 9 9 Fuzzy New Holland Vittadinia cuneata 9 9 daisy Woolly New Holland Vittadinia gracilis 9 9
A-1
Family Common name Species Northern Port Wakefield Expressway Road Upgrade daisy Vittadinia sp. 9 Crassulaceae Dense crassula Crassula colorata 9 Cupressaceae Southern cypress pine Callitris gracilis 9 Cyperaceae Salt club-rush Bolboschoenus caldwellii 9 9 Spiny flat-sedge Cyperus gymnocaulos 9 9 Common spike-rush Eleocharis acuta 9 9 Smooth cutting grass Gahnia filum 9 9 Euphorbiaceae Caustic weed Euphorbia drummondii 9 9 Frankeniaceae Common sea-heath Frankenia pauciflora 9
Gramineae Common swamp Amphibromus nervosus 9 wallaby-grass Wire grass Aristida australis 9
Common wallaby-grass Austrodanthonia caespitosa 9 9
Velvet wallaby-grass Austrodanthonia pilosa 9
- Austrodanthonia racemosa 9 9 var. racemosa Small-flower wallaby- Austrodanthonia setacea 9 9 grass var. setacea Short-crest spear-grass Austrostipa curticoma 9 Crested spear-grass Austrostipa blackii 9 Rusty spear-grass Austrostipa eremophila 9 Balcarra spear-grass Austrostipa nitida 9 Tall spear-grass Austrostipa nodosa 9 9 Flat-awn spear-grass Austrostipa platychaeta 9 Rough spear-grass Austrostipa scabra ssp. 9 9 Red-leg grass Bothriochloa macra 9 Windmill grass Chloris truncata 9 9 Black-head grass Enneapogon nigricans 9 9 Umbrella grass Enteropogon acicularis 9 9 Barren cane-grass Eragrostis infecunda 9 9
Swamp cane-grass Eragrostis dielsii 9 Rigid panic Whalleya proluta 9 Warrego summer-grass Paspalidium jubiflorum 9
A-2
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Common reed Phragmites australis 9 9 Australian saltmarsh- Puccinellia stricta 9 grass Kangaroo grass Themeda triandra 9 Juncaceae Pale rush Juncus pallidus 9 Hoary sea-rush Juncus radula 9 Finger rush Juncus subsecundus 9 9 Leguminosae Gold dust wattle Acacia acinacea 9 9 Hakea wattle Acacia hakeoides 9 Umbrella bush Acacia ligulata 9 Kangaroo thorn Acacia paradoxa 9 9 Golden wattle Acacia pycnantha 9 9 Willow wattle Acacia salicina 9 Elegant wattle Acacia victoriae 9 Desert senna Senna artemisioides (x 2 9 ssp) Liliaceae Short-stem flax-lily Dianella brevicaulis 9 Black anther flax-lily Dianella revoluta 9 Scented matt rush (iron Lomandra effusa 9 grass) Iron grass L. multiflora ssp. dura 9 Lythraceae Lesser loosestrife Lythrum hyssopifolia 9 9 Malvaceae Corrugated sida Sida corrugata 9 Marsileaceae Nardoo Marsilea drummondii 9 9 Myoporaceae Weeping emu-bush Eremophila longifolia 9 Sugarwood Myoporum platycarpum 9 ssp. perbellum Myrtaceae River red gum Eucalyptus camaldulensis 9 9 White mallee Eucalyptus dumosa 9 Black box Eucalyptus largiflorens 9 Peppermint box Eucalyptus odorata 9 Mallee box Eucalyptus porosa 9 9 Red mallee Eucalyptus socialis 9 Melaleuca acuminata 9 Dryland tea-tree Melaleuca lanceolata ssp. 9 lanceolata Nyctaginaceae Tar vine Boerhavia dominii 9 9 Orchidaceae Greencomb spider- Caladenia tensa 9 -
A-3
Family Common name Species Northern Port Wakefield Expressway Road Upgrade orchid Pale leek-orchid Prasophyllum pallidum - - Pittosporaceae Native apricot Pittosporum phylliraeoides 9 var. microcarpa Plantaginaceae Variable plantain Plantago varia 9 Polygonaceae Lignum Muehlenbeckia florulenta 9 9 Wiry dock Rumex dumosus 9 Potamogetonaceae Widgeon grass Ruppia tuberosa 9 Santalaceae Quandong Santalum acuminatum 9 Typhaceae Narrow-leaf bulrush Typha domingensis 9 9 Zygophyllaceae Nitre-bush Nitraria billardierei 9 9
A-4
Attachment B
Introduced flora species in Northern Expressway and Port Wakefield Road Upgrade area
Introduced flora species in Northern Expressway and Port Wakefield Road Upgrade area
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Aizoaceae Pig-face Carpobrotus edulis 9 Coastal galenia Galenia pubescens var. 9 pubescens Blanketweed Galenia secunda 9 9 Common iceplant Mesembryanthemum 9 9 crystallinum Slender iceplant Mesembryanthemum 9 9 nodiflorum Asparagaceae Bridal creeper Asparagus 9 asparagoides Boraginaceae Salvation Jane Echium plantagineum 9 9 Common heliotrope Heliotropium 9 9 europaeum Cactaceae Prickly pear Opuntia spp. (x4) 9 9 Caryophyllaceae Small mouse-ear chickweed Cerastium 9 9 semidecandrum Sea pearlwort Sagina sp. 9 Salt sand-spurrev Spergularia marina 9 Casuarinaceae Swamp oak Casuarina glauca 9 Drooping sheoak Allocasuarina verticillata 9 Chenopodiaceae Seablite Suaeda baccifera 9 Compositae Creeping knapweed Acroptilon repens 9 9 Capeweed Arctotheca calendula 9 9 Wild aster Aster subulatus 9 9 Skeleton weed Chondrilla juncea 9 9 Boneseed Chrysanthemoides 9 9 monilifera Spear thistle Cirsium vulgare 9 9 Flaxleaf fleabane Conyza bonariensis 9 9 Ferny cotula Cotula bipinnata 9 9 Water-buttons Cotula coronopifolia 9 Artichoke thistle Cynara cardunculus 9 9 Stinkwort Dittrichia graveolens 9 9 Gazania Gazania sp. (G. rigens 9 9 and cultivars) Smooth catsear Hypochaeris glabra 9 9 Rough catsear Hypochaeris radicata 9 9 Prickly lettuce Lactuca serriola 9 9
B-1
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Calomba daisy Oncosiphon suffruticosa 9 9 Stemless thistle Onopordum acaulon 9 9 Golden pallenis Pallenis spinosa 9 9 False sow-thistle Reichardia tingitana 9 9 African daisy Senecio pterophorus 9 9 Variegated thistle Silybum marianum 9 9 Common sow-thistle Sonchus oleraceus 9 9 Bathurst burr Xanthium spinosum 9 9 Noogoora burr Xanthium strumarium 9 9 Convolvulaceae Field bindweed Convolvulus arvensis 9 9 Morning glory vine Ipomoea indica 9 Crassulaceae - Aeonium aboreum 9 Crassula Crassula brevifolia 9 Crassula Crassula tetragona ssp. 9 robusta Cruciferae Long-fruited wild turnip Brassica tournefortii 9 9 Two-horned sea-rocket Cakile maritima ssp. 9 maritima Lincoln weed Diplotaxis tenuifolia 9 9 Oval purse Hymenolobus 9 procumbens Common peppercress Lepidium africanum 9 9 Musk weed Myagrum perfoliatum 9 9 Wild radish Raphanus raphanistrum 9 9 Short-fruited wild turnip Rapistrum rugosum 9 9 Cyperaceae Drain sedge Cyperus eragrostis 9 9 Nut-grass sedge Cyperus rotundus 9 9 Dipsacaceae Scabious Scabiosa atropurpurea 9 9 Euphorbiaceae Milk caper Euphorbia peplus 9 9 False caper Euphorbia terracina 9 9 Castor oil plant Ricinus communis 9 9 Frankeniaceae Annual frankenia Frankenia pulverulenta 9 Fumariaceae Fumitory Fumaria capreolata 9 9 Geraniaceae Long storks bill Erodium botrys 9 9 Musky storks bill Erodium moschatum 9 9 Gramineae Bamboo Arundo donax 9 9
B-2
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Bearded oat Avena barbata 9 9 Wild oats Avena fatua 9 9 False brome Brachypodium 9 9 distachyon Prairie grass Bromus catharticus 9 9 Jabbers Bromus diandrus 9 9 Soft brome Bromus hordeaceus 9 9 ssp. hordeaceus Red brome Bromus rubens 9 9 Innocent grass Cenchrus longispinus 9 9 Pampas grass Cortaderia selloana 9 Couch grass Cynodon dactylon 9 9 Perennial veldt grass Ehrharta calycina 9 Annual veldt grass Ehrharta longiflora 9 9 Stinkgrass Eragrostis cilianensis 9 9 African lovegrass Eragrostis curvula 9 9 Sea barley-grass Hordeum marinum 9 Barley-grass Hordeum murinum 9 9 Coolatai grass Hyparrhenia hirta 9 9 Perennial ryegrass Lolium perenne 9 9 Annual ryegrass Lolium rigidum 9 9 Curly ryegrass Parapholis incurva 9 Kikuyu Pennisetum 9 9 clandestinum African feather grass Pennisetum macrourum 9 9 Feathertop grass Pennisetum villosum 9 9 Pussytails Pentaschistus pallida 9 9 Phalaris Phalaris aquatica 9 9 Canary-grass Phalaris canariensis 9 Lesser canary-grass Phalaris minor 9 9 Rice millet Piptatherum miliaceum 9 9 Annual meadow-grass Poa annua 9 9 Annual beard-grass Polypogon 9 9 monspeliensis Annual cats tail Rostraria cristata 9 9 Arabian grass Schismus barbatus 9 9 Wedge-foot grass Sphenopus divaricatus 9
B-3
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Squirrel-tail fescue Vulpia bromoides 9 9 Rats tail fescue Vulpia myuros forma 9 9 myuros Guttiferae St John's wort Hypericum perforatum 9 - Iridaceae Thread iris Gynandriris setifolia 9 9 One-leaf cape-tulip Homeria flaccida 9 9 Juncaceae Sharp rush Juncus acutus 9 9 Lamiaceae Horehound Marrubium vulgare 9 9 Wild sage Salvia verbenaca 9 9 Leguminosae Western coastal wattle Acacia cyclops 9 9 Flinders Ranges wattle Acacia iteaphylla 9 9 Coastal wattle Acacia longifolia ssp. 9 sophorae Golden wreath wattle Acacia saligna 9 9 Burr-medic Medicago polymorpha 9 9 King Island melilot Melilotus indica 9 9 Common melilot Melilotus officinalis 9 9 Narrow-leafed clover Trifolium angustifolium 9 Hares foot clover Trifolium arvense var. 9 arvense Cluster clove Trifolium glomeratum 9 Woolly clover Trifolium tomentosum 9 Common vetch Vicia sativa 9 Liliaceae Three-cornered garlic Allium triquetrum 9 Crow garlic Allium vineale 9 9 Onion weed Asphodelus fistulosus 9 9 Limoniaceae Sea lavender Limonium companyonis 9 9 Limonium sinuatum 9 9 Malvaceae Marshmallow Malva parviflora 9 9 Myrtaceae Sugar gum Eucalyptus cladocalyx 9 9 Yellow flowering gum Eucalyptus woodwardii 9 Bracelet honey myrtle Melaleuca armillaris 9 9 Dry land tea tree Melaleuca lanceolata 9 Western honey-myrtle Melaleuca nanophylla 9 Oleaceae Desert ash Fraxinus angustifolia 9 Olive Olea europaea 9 9
B-4
Family Common name Species Northern Port Wakefield Expressway Road Upgrade Onagraceae Evening primrose Oenothera stricta ssp. 9 stricta
Oxalidaceae Soursob Oxalis pes-caprae 9 9 Oxalis corniculata 9 9 Oxalis sp. 9 Plantaginaceae Bucks-horn plantain Plantago coronopus 9 9 Ribgrass Plantago lanceolata var. 9 9 lanceolata Polygonaceae Three-cornered jack Emex australis 9 9 Wireweed Polygonum aviculare 9 9 Clustered dock Rumex conglomeratus 9 9 Resedaceae Cut-leaf mignonette Reseda lutea 9 9 Rosaceae Dog rose Rosa canina 9 9 Scrophulariaceae Toadflax Kickxia elatine 9 Solanaceae African boxthorn Lycium ferocissimum 9 9 Tree tobacco Nicotiana glauca 9 9 Silverleaf nightshade Solanum elaeagnifolium 9 9 Black nightshade Solanum nigrum 9 9 Umbelliferae Fennel Foeniculum vulgare 9 9 Urticaceae Stinging nettle Urtica urens 9 9 Zygophyllaceae Caltrop Tribulus terrestris 9 9
B-5