7.2
VEGETATION AND FLORA
7.2.1
Overview
As detailed in Section 5.2.1, the following vegetation and flora characteristics apply to the Study
Area:
the flora of the Study Area is diverse, with approximately 1016 recorded vascular species;
26 Beard vegetation associations were recorded in the Study Area. Seven of these
associations have potentially been cleared to less than 30% of their pre‐European extent.
All of these are located in the freehold area, within the Geraldton Sandplains IBRA region;
72 vegetation units were recorded by Ecologia in the Study Area. Vegetation units of
interest include the Mulga woodlands in the Murchison region and the salt lake
communities near Weld Range;
within the pastoral area the original extent of native vegetation largely remains, however it
has been altered through grazing, changed fire regimes, etc;
within the freehold area there has been extensive clearing;
no nationally or state listed TECs were recorded in the Study Area. Four Priority 1 PEC
communities of state significance were recorded:
1. Jack Hills vegetation complexes;
2. Plant assemblages of the Moresby Range;
3. Tallering Peak Vegetation complexes; and
4. Weld Range Vegetation complexes.
two Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act) listed flora
species were recorded within the Proposal Area boundaries, Caladenia hoffmanii
(Endangered) and Eucalyptus blaxellii (Vulnerable), and a further species, Drummondita
ericoides
(Endangered),
was confirmed as occurring in the Proposal Area using DEC records;
a total of two DRF and 87 Priority Flora taxa have been recorded in the Proposal Area; and
62 weed species were recorded in the Study Area, including three Declared plant species
(WA): Carthamus lanatus, Echium plantagineum and Emex australis. Invasive species are
more prevalent within the freehold land area than in the pastoral area.
7.2.2
Key statutory requirements, environmental policy and guidance
7.2.2.1
EPA Objectives
The EPA objective for the management of flora and vegetation is to maintain the abundance,
diversity, geographic distribution and productivity of flora at species and ecosystem levels through
the avoidance or management of adverse impacts and improvement in knowledge.
7.2.2.2
EPA statements and guidelines
The following EPA statements are applicable to the Proposal:
EPA Position Statement No. 2 ‐ Environmental Protection of Native Vegetation in Western
Australia;
Position Statement No. 3 ‐ Terrestrial Biological Surveys as an Element of Biodiversity
Protection;
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Guidance statement 51 ‐ Terrestrial Flora and Vegetation Surveys for Environmental Impact
Assessment in Western Australia; and
EPA Guidance Statement No. 6 ‐ Rehabilitation of Terrestrial Ecosystems (EPA, 2006).
EPA Position Statement No. 2
EPA Position Statement No. 2 provides an overview of the EPA’s position on the clearing of native
vegetation in Western Australia (WA). In assessing a proposal, the EPA’s consideration of biological
diversity includes the following basic elements:
comparison of development scenarios or options on biodiversity at the species and
ecosystems level;
no known species of plant or animal is caused to become extinct as a consequence of the
development and the risks to threatened species are considered to be acceptable;
no association or community of indigenous plants or animals ceases to exist as a result of
the proposal;
there is a comprehensive, adequate and secure representation of scarce or endangered
habitats within the project area, and/or in areas which are biologically comparable to the
project area, protected in secure reserves;
if the project is large (in the order of 10 ha to 100 ha or more, depending on where in the
State) the project area itself should include a comprehensive and adequate network of
conservation areas and linking corridors whose integrity and biodiversity are secure and
protected; and
the on‐site and off‐site impacts of the project are identified and the proponent
demonstrates that these impacts can be managed.
EPA Position Statement No. 3
EPA Position Statement No. 3 presents the principles the EPA apply when assessing proposals which
may impact on biodiversity values in WA. The intended outcomes of this Position Statement are:
to promote and encourage all proponents and their consultants to focus their attention on
the significance of biodiversity and therefore the need to develop and implement best
practice in terrestrial biological surveys; and
to enable greater certainty for proponents in the environmental impact assessment process
by defining the principles the EPA will use when assessing proposals which may impact on
biodiversity values.
EPA Guidance Statement No. 51
EPA Guidance Statement No. 51 provides guidance on standards and protocols for terrestrial flora
and vegetation surveys, particularly those undertaken for the environmental impact assessment of
proposals
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7.2.2.3
Applicable Legislation and Policy
State legislation
The conservation of vegetation and flora is covered primarily by the following legislation:
Wildlife Conservation Act 1950 (WC Act);
Environmental Protection Act 1986 (EP Act); and
Conservation and Land Management Act 1984.
In WA, all flora native to the State are protected under the WC Act and threatened flora must be
‘declared’ and listed in the Wildlife Conservation (Rare Flora) Notice 2008. DRF are species that have
been adequately searched for, and are deemed to be either rare, in danger of extinction, or
otherwise in need of special protection.
DEC maintains a list of TECs and PECs. Possible TECs that do not meet survey criteria or that are not
adequately defined are listed as PECs under Priorities 1, 2 and 3. Ecological communities that are
adequately known, are rare but not threatened, or meet criteria for Near Threatened, or that have
been recently removed from the threatened list, are placed in Priority 4. Conservation Dependent
ecological communities are placed in Priority 5.
National legislation
The conservation of vegetation and flora is addressed primarily by the EPBC Act.
In 1974, Australia became a signatory to the Convention on International Trade in Endangered
Species of Wild Fauna and Flora (CITES). An official list of endangered species was prepared in
response to this signing and is regularly updated. This listing is administered through the EPBC Act.
The current list differs from the various State lists though some listed species are common.
Strategies and policies
The State and Commonwealth governments have endorsed the National Strategy for the
Conservation of Australia’s Biological Diversity (Commonwealth of Australia 1996) and the National
Strategy for Ecologically Sustainable Development (Commonwealth of Australia 1992). The strategies
address the conservation of Australia’s biological diversity by defining several guiding principles.
Other applicable policies and strategies for the management of flora include:
Environmental Weed Strategy for WA (DEC, 1999); and
Conservation and Land Management (CALM) Policy Statement No 9, Conserving Threatened
Species and Ecological Communities (CALM, 1999).
7.2.3
Aspects and Impacts
The environmental aspect identified as posing the most significant risk to both general and
conservation significant vegetation and flora within the Proposal Area is vegetation clearing.
Potential impacts as discussed within this section refer to both direct impacts on flora and vegetation
from vegetation clearing, and indirect impacts on sheet‐flow dependant vegetation as a result of
changes to surface water hydrology as a result of the Proposal.
The Proposal is expected to require the disturbance of approximately 7000 ha of land. It is expected
that 6000 ha of native vegetation will need to be cleared, of which a maximum of 100 ha is within the
freehold area, and the remainder is in the pastoral area.
Other environmental aspects identified as being of less risk to vegetation and flora include:
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ore haulage (dust emissions);
groundwater extraction;
vehicle, machinery activity; and
hydrocarbon storage and management.
Impacts to vegetation associated with Proposal activities may include:
Direct removal of vegetation: Loss of vegetation due to clearing;
Increase in weeds: Weeds may be transported to unaffected areas by moving seeds
between locations as a result of construction activities such as topsoil movement and
storage, earthmoving equipment and light vehicles. This decreases vegetation condition,
can reduce native vegetation cover and diversity, and alter population dynamics within
vegetation communities;
Loss of condition due to increase in erosion or sedimentation: Erosion is predominantly
caused by vegetation clearing, as the vegetation plays a role in reinforcing the soil
structure. Changed drainage/surface water characteristics can also lead to erosion;
Impacts on local drainage causing impacts on vegetation (including sheetflow dependent
vegetation): Rail Corridors and borrow pits can impede the flow of surface water (including
sheetflow) down slope, resulting in a runoff water reduction on the downstream side, thus
affecting downstream vegetation. Mulga trees are particularly susceptible to subtle
changes in surface water distribution patterns;
Damage to vegetation from uncontrolled or unintentional fire: The Proposal Area is
predominantly dry for most of the year and therefore fire events can start easily and
quickly, and construction and operational works increase fire risk e.g. from sparks, vehicles,
cigarettes, flammable liquids, or welding; and
Fragmentation: Clearing increases fragmentation of vegetation and flora populations,
therefore reducing the strength of the populations and increasing edge effects. Loss of
diversity, cover and/or condition of vegetation can result; and
Loss of condition due to dust settlement: Dust during construction or operation may cause
increased dust settlement on vegetation immediately surrounding construction or
operational areas.
7.2.4
Vegetation and Flora Impact Assessment
For this assessment, the significance of the loss or disturbance of vegetation and flora by the
Proposal was determined by considering:
regional abundance of the vegetation communities;
representation in existing or proposed conservation reserves;
the presence of Priority or Declared Rare Flora species; and
the presence of threatening processes (e.g. weeds).
The assessment of the significance of impacts (following the application of management measures)
on significant flora was on the basis of change in the distribution and abundance of EPBC Act listed,
Declared Rare and Priority Flora species, and compliance with the Wildlife Conservation Act 1950.
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The impact assessment within the following section is based on the following sources scales of survey
data:
detailed scale ‐ Study Area surveys undertaken by Ecologia (2010a) incorporating findings
from previous flora surveys; and
regional scale Beard and Burns (1976) vegetation mapping, which is the only data available
for comparison at a regional scale (Geraldton Sandplains Bioregion).
Indicative Proposal component disturbance areas are detailed in Table 7‐1. It is estimated that up to
100 ha of native vegetation will need to be cleared through the freehold area.
Table 7‐1 Estimated area of disturbance
Component
Main Line (ha)
Weld Range Spur (ha)
Mullewa Rail Spur (ha)
Rail formation
1850
100
70
Construction Camps
600
0
0
Borrow Areas
1100
70
50
Quarries 150
0
0
Access Roads
2100
100
80
Water Bores
100
10
10
Laydown Areas
320
10
10
Fibre
Optic
Cable 300 20
10
Total Disturbance Areas
6510
310
230
7.2.4.1
Priority Ecological Communities
Four Priority 1 PECs occur within the Proposal Area; Jack Hills, Moresby Range, Tallering Peak and
Weld Range vegetation complexes (see Table 5‐7 for details).
PECs will not be directly impacted by the Proposal as they have been considered a non‐negotiable
constraint for Rail Corridor alignment. All PECs will be avoided and a 50 m buffer will be put in place
around these areas for both construction and operation.
As all PECs are associated with ranges and peaks, it is unlikely they will be significantly impacted by
the Proposal through indirect effects such as changes to surface water flows, erosion, sedimentation,
or exposure to wastes or hydrocarbon leaks
.
The buffer area will also minimise potential direct
impacts to PECs from fire, weed spread, and dust.
7.2.4.2
Significant vegetation communities
Both Beard (1976) vegetation association mapping and Ecologia vegetation unit mapping were used
to determine significant vegetation communities, in conjunction with data for the IBRA subregions.
Beard vegetation associations
A systematic survey of native vegetation was undertaken in the 1970s, which described vegetation
systems in WA. The Geraldton area was mapped at 1:250,000 scale by Beard and Burns (1976), with
the dataset being converted to a digital form by DAFWA (2006). This vegetation association dataset
has been used to determine the significance of vegetation at the Geraldton Sandplains Bioregion
scale.
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A vegetation association was determined to be significant if less than 30% of the communities’ pre‐
European extent remained, based on the following criteria provided in EPA Position Statement 2:
i.
The “threshold level’ below which species loss appears to accelerate exponentially at an
ecosystem level is regarded as being a level of 30% of the pre‐clearing extent of the
vegetation type
ii.
A level of 10% of the original extent is regarded as being a level representing “endangered”
iii.
Clearing which would put the threat level into the class below should be avoided
iv.
From a biodiversity perspective, stream reserves should generally be in the order of at least
200 m wide
As clearing is limited in the pastoral area, only the freehold area contained vegetation units with less
than 30% of their pre‐European extent remaining. The freehold area is entirely within the
boundaries of the Geraldton Sandplains Interim Biogeographic Regionalisation of Australia (IBRA)
region.
Four vegetation associations mapped in the Proposal Area have been identified as endangered, that
is, having less than 10% of their pre‐European extents remaining within the Geraldton Sandplains
(GS) IBRA region (EPA, 2000a and WAPC, 2010). A further eight vegetation associations mapped in
the Proposal Area have been identified as vulnerable, that is, having greater than 10% but less than
30% of their pre‐European extents remaining within the IBRA region (EPA, 2000a and WAPC, 2010).
Table 7‐2 lists the twelve significant vegetation associations within the Geraldton Sandplains IBRA
region.
Table 7‐2 Beard vegetation associations within the Proposal Area with <30% of their pre‐European
extent remaining
Unit Code
Pre-European
extent in WA (ha)
Pre-European extent
in GS region (ha)
Degree of endemism
(% of total pre-
European extent
within GS region)
Current extent
remaining in
the GS region
% of original
extent
remaining in
the GS region
a33Sc*
3,478
1,749
Moderate (50)
370
21.1
acSc*
495,385
118,103
Low (24)
6,422
5
ceLr a9Si*
511,008
1,248
Low (0.24)
0
0
e6,8Mi
796,448
2,194
Low (0.28)
117
5.3
e6c5Mr a9,19Si*
56,427
17,554
Moderate (31)
4,617
26
e6Mr a19Si*
184,571
184,571
High (100)
31,410
17
e6Mr eaSi*
97,368
96,821
High (99)
7,470
8
k1, 3Ci
64,719
4,454
Low (7)
1,145
25.7
mhSc* 51,880
51,880
High
(100)
14,221
27
x2SZc* 328,738
328,738
High
(100)
43,126
13
x3SZc* 580,547
507,874
Moderate-High
(87)
52,364
10.3
x3SZc/acSc* 82,081 82,081 High
(100) 9,276 11
As all vegetation units presented in Table 7‐2 have less than 30% of their pre‐European extent
remaining within the Geraldton Sandplains IBRA region, they are all considered to be vulnerable
regionally. However, due to the narrow linear nature of the Proposal, it is unlikely that the Proposal
will result in a significant impact to any one vegetation association. The Proposal will avoid all native
vegetation in the freehold area where practicable (there are some sections of the Rail Corridor that
cannot avoid some vegetated areas).
Associations a33Sc, acSc, ceLr a9Si, e6,8Mi and e6c5Mr a9,19Si are present within the Geraldton
Sandplains bioregion but also occur extensively outside the bioregion. The extent to which these
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associations have been cleared elsewhere in the state is not available; therefore the current extent
cannot be determined. It is assumed that since the degree of clearing diminishes further to the east,
due to the lower levels of agricultural and urban development, these associations have a higher level
of preservation, albeit in variable condition due to grazing, than is reported in Table 7‐2.
Vegetation associations acSc, ceLr a9Si, e6Mr a19Si, mhSc, x2SZc and x3SZc all have more than 95%
of their current extent located outside of the Proposal Area, and a very small fraction of these
associations within the Proposal Area will be impacted.
The distribution of e6,8Mi shows that the association is large and widespread, and of the total area
of the Beard association, only 0.04% of its current extent occurs within the Proposal Area.
Based on the known current extent of e6c5Mr a9,19Si in the Geraldton Sandplains region, 24%
occurs within the Proposal Area, however this association is not endemic to this region (31% of the
total area is in the Geraldton Sandplains).
k1,3Ci is a small and restricted Beard association that is mapped as 0.2% of the Proposal Area. Of the
total pre‐European extent of the Beard unit, 0.7% occurs within the Proposal Area. This unit is not
endemic to the Geraldton Sandplains region (7% of its total is in the Geraldton Sandplains region).
e6Mr eaSi and x3SZc/acSc are more endemic to the Geraldton Sandplains Region, and considered to
be two of the most significant associations when it comes to finalising the rail alignment and
managing impacts.
a33Sc is a very small and restricted Beard association that is mapped as 0.5% of the Proposal Area. Of
the total pre‐European extent of the Beard association, 50% occurs within the Proposal Area. This
vegetation is very significant in the Proposal Area as such a large percentage of its total is mapped.
a33sc occurs at the western end of the Proposal Area. Most of this vegetation association is skirted
by the indicative rail alignment (Figure 5‐7).
e6Mr eaSi is a small and restricted Beard association that is mapped as 3.6% of the Proposal Area.
This association is very restricted and is likely to be uncommon locally and regionally and is almost
endemic (99%) to the Geraldton Sandplains region. Based on the known current extent of this
vegetation association in the Geraldton Sandplains region, 10% occurs within the Proposal Area. The
indicative alignment crosses only one patch of this vegetation association (Figure 5‐9).
x3SZc is a large and widespread Beard association that is mapped as 1.7% of the Proposal Area. Of
the total pre‐European extent of the Beard association, 0.6% occurs within the Proposal Area. Based
on the known current extent of this vegetation association in the Geraldton Sandplains region, 1%
occurs within the Proposal Area. This association is highly endemic to the Geraldton Sandplains
region (87% of its total area). The indicative rail alignment crosses some patches of x3SZc (Figure
5‐9).
Table 7‐3 below lists the significant vegetation associations that are expected to be impacted by the
Proposal, and the proportion of the association expected to be impacted. As native vegetation
clearing will be avoided where practicable through the freehold area, disturbance will be only from
the Rail Corridor (average of up to 100 m width in these vegetated areas). Descriptions of each code
are listed in Section 5.2.1. Figure 5‐7 to Figure 5‐9 shows the location of these vegetation
associations.
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