Proposed offset Portion of Lot 1, 1395 Banovich Road, Hill
Area: 1993 ha including 1771.5 ha native
vegetation and 27.5 ha of highly modified
Time horizon (years) Time over which loss is averted
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | iii
Offset calculator attribute
Time until ecological benefit
Start area (ha) 564 ha
Start quality (scale of 1-10) 9
Future area and quality with and without offset (%) Risk of loss (%) without offset
Future quality without offset (scale 1-10)
Risk of loss (%) with offset
Future quality with offset (scale 1-10)
Confidence in result (%) Averted loss component input
Change in habitat quality component input
Net present value (adjusted hectares) 75.63
iv | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
Table of contents
Vegetation associations recorded during the field survey ................................................. 22
Extent of vegetation condition ratings within the survey area ........................................... 27
Summary of Likelihood of Occurrence Assessment .......................................................... 33
Fauna habitat types within survey area ............................................................................. 37
Type and extent of Carnaby’s Black Cockatoo habitat within the survey area
(1993 ha) ............................................................................................................................ 50
Tree Plot Data from the Survey Area ................................................................................. 51
Summary of fauna species of conservation significance recorded during survey
and determined likely to occur within the survey area ....................................................... 53
Summary of inputs into Offset Calculator .......................................................................... 61
Relevant legislation, conservation codes and background information
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 1
Main Roads Western Australia (Main Roads) is currently constructing Stage 1 of the Mitchell
Freeway Extension (project). The ultimate works for the project have been divided in to three
stages, of which Stage 1 includes the works associated with the extension from Burns Beach
Road to Hester Avenue and the connecting roads (Neerabup Road and Hester Avenue).
Stage 1 was referred to the Department of the Environment (DotE
) under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and was determined to be a
‘controlled action’ due to the likely significant impacts on Carnaby’s Black Cockatoo
(Calyptorhynchus latirostris). The impact is clearing of 88.7 hectares (ha) of native vegetation
that provides known and potential foraging, roosting and breeding habitat for Carnaby’s Black
Condition 3 of EPBC approval 2013/7091 stipulated that Main Roads must provide an offset
property with suitable environmental values to be transferred to the Conservation and Parks
Commission of Western Australian and managed by Department of Parks and Wildlife, to be
reserved for conservation in perpetuity.
Main Roads acquired a potential offset property (Lot 1, 1395 Banovich Road, Hill River). A
biological survey (‘Ecological Values Assessment’) including a Black Cockatoo habitat
assessment was commissioned to determine the environmental values of the property. The
property consists of 1,993 ha (survey area) of bushland in the locality of Hill River (near the
town of Jurien), situated approximately 170 kilometres (km) from the project.
Purpose of this report
The purpose of the assessment was to delineate key flora, vegetation, fauna, soil values within
the survey area. The outcomes of the assessment will be used to determine the suitability of the
property being used as an offset for the project and for future Main Roads offsets.
A study area was defined for the desktop based searches of the survey area and includes a 20
km buffer around the survey area.
Biological survey area
The survey area is located west of Banovich Road and north of Jurien Road, approximately 20
km east northeast of Jurien town site, in the Shire of Dandaragan. The location of the survey
area is mapped in Figure 1, Appendix A.
Scope of works
The scope of works, as detailed in the Main Roads Consultants Brief was to undertake a
desktop assessment and Level 1 flora, vegetation and fauna survey, including targeted Black
Cockatoo habitat assessment for the project. The following actions were undertaken:
The Department of the Environment is now the Department of the Environment and Energy (DotEE)
2 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
Complete a desktop assessment of the study area prior to the field survey work to identify
all biological features and constraints, which may be in, or nearby the survey area
Identify and review any existing and relevant environmental reports
Identify significant flora, vegetation/ecological communities, fauna, soil, groundwater and
surface water values and potential sensitivity to impact
Identify broad pre-European vegetation type(s) using Beard (various)
Conduct a Level 1 field survey (to be done by an environmental specialist in accordance
with regulatory expectation for years of experience in the relevant bioregion) to
verify/ground truth the desktop assessment findings through targeted and comprehensive
Undertake vegetation condition mapping using an appropriate condition scale for the
bioregion (as per Environmental Protection Agency (EPA) and DPaW 2015)
Undertake ecological community mapping to a scale appropriate for the bioregion and
described according to the National Vegetation Information System (NVIS) structure and
Undertake targeted Black Cockatoo habitat assessment and mapping
Assess the project areas plant species diversity, density, composition, structure and weed
cover, recording the percentage of each in 20 flora sampling quadrats.
The biological survey aspects that relate to flora were undertaken having regard tothe EPA and
DPaW (2015) Technical Guide and those aspects that relate to fauna were undertaken having
regard to EPA Guidance Statement No.56 (EPA 2004) and the subsequent Technical Guide
(EPA and Department of Environment and Conservation (DEC) 2010).
Relevant legislation, conservation codes and background
In Western Australia some ecological communities, flora and fauna are protected under both
Federal and State Government legislation. In addition, regulatory authorities also provide a
range of guidance and information on expected standards and protocols for environmental
An overview of key legislation and guidelines, conservation codes and background information
relevant to this biological survey is provided in Appendix B.
Report limitations and assumptions
This report has been prepared by GHD for Main Roads and may only be used and relied on by
Main Roads for the purpose agreed between GHD and the Main Roads as set out in section 1.3
of this report.
GHD otherwise disclaims responsibility to any person other than Main Roads arising in
connection with this report. GHD also excludes implied warranties and conditions, to the extent
The services undertaken by GHD in connection with preparing this report were limited to those
specifically detailed in the report and are subject to the scope limitations set out in the report.
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 3
The opinions, conclusions and any recommendations in this report are based on conditions
encountered and information reviewed at the date of preparation of the report (including species
listings). GHD has no responsibility or obligation to update this report to account for events or
changes occurring subsequent to the date that the report was prepared.
The opinions, conclusions and any recommendations in this report are based on assumptions
made by GHD described in this report. GHD disclaims liability arising from any of the
assumptions being incorrect.
GHD has prepared this report on the basis of information provided by Main Roads and others
who provided information to GHD (including Government authorities), which GHD has not
independently verified or checked beyond the agreed scope of work. GHD does not accept
liability in connection with such unverified information, including errors and omissions in the
report which were caused by errors or omissions in that information.
The opinions, conclusions and any recommendations in this report are based on information
obtained from, and testing undertaken at or in connection with, specific sample points. Site
conditions at other parts of the site may be different from the site conditions found at the specific
Investigations undertaken in respect of this report are constrained by the particular site
conditions, such as the location of access tracks, operational works, services and vegetation. As
a result, not all relevant site features and conditions may have been identified in this report.
Site conditions may change after the date of this Report. GHD does not accept responsibility
arising from, or in connection with, any change to the site conditions. GHD is also not
responsible for updating this report if the site conditions change.
This report has assessed the flora and fauna within the survey area (Figure 1, Appendix A).
Should the survey area change or be refined, further assessment may be required.
4 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
Prior to the commencement of the field survey, a desktop assessment was undertaken to
identify relevant environmental information pertaining to the study area and to assist in survey
design. The search parameters used were a 20 km radius of a point at 30° 11
” S, 11
. This included a review of:
The DotEE Protected Matters Search Tool (PMST) to identify communities and species
listed under the EPBC Act potentially occurring within the study area (DotEE 2016a)
The DPaW Threatened Ecological Communities (TECs) and Priority Ecological
Communities (PECs) database (Reference Number: 14-0716EC) to determine the
potential for TECs or PECs to be present within the study area
The NatureMap database for flora and fauna species previously recorded within the study
area (DPaW 2016) (Appendix C)
The DPaW Threatened (Declared Rare) and Priority Flora (TPFL) database
Number: 02-0816FL), the DPaW Threatened and Priority Fauna database (Reference
Number: FAUNA#5265), and the WA Herbarium database for Threatened flora and fauna
species listed under the Wildlife Conservation Act 1950 (WC Act) and listed as Priority by
the DPaW, previously recorded within the study area
Existing datasets including previous vegetation mapping of the survey area (Beard 1979),
aerial photography, geology/soils and hydrology information to provide background
information on the variability of the environment, likely vegetation units and fauna habitats
and to identify areas with potential to contain TECs, PECs, and Threatened and Priority
listed flora and fauna species.
Vegetation and flora
As part of the biological survey, a Level 1 single season vegetation and flora assessment of the
survey area was conducted by botanists Mathew Gannaway (SL011729) and Joshua Foster
(SL011812) from the 1 to 5 August 2016. The field survey was undertaken to verify the results
of the desktop assessment, identify and describe the dominant vegetation units where possible,
assess vegetation condition and identify and record vascular flora taxa present at the time of
survey. Searches for conservation significant ecological communities and flora taxa were also
The survey methodology employed was undertaken with reference to the EPA and DPaW
Technical Guide – Terrestrial Flora and Vegetation Surveys for Environmental Impact Assessment (EPA and DPaW 2015).
Data collection Field survey methods involved a combination of sampling quadrats located in identified
vegetation units and traversing the survey area by foot. Twenty pegged quadrats (measuring 10
metres (m) x 10 m) were recorded in the survey area. To sample all the apparent vegetation
DPAW would only supply data for a 5 km radius search of the survey area for the DPAW TPFL
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 5
units across the survey area, the location of quadrats was made primarily on the basis of aerial
photographic maps. The locations of TECs and PECs were previously recorded within the
survey area were targeted. Additional sites were selected in situ, based on observations of
vegetation units during the field assessment.
Field data for each quadrat were recorded on a pro-forma data sheet and included the
parameters detailed in Table 1. Quadrat data are provided to Main Roads in Excel format.
Data collected during the flora and vegetation field survey
Personnel/recorder; date, quadrat dimensions, photograph of the
Aspect, soil attributes, ground surface cover, leaf and wood litter.
Coordinates recorded in GDA94 datum using a hand-held Global
Positioning System (GPS) tool to accuracy approximately ± 10 m.
Location recorded at the north-west corner peg.
The vegetation condition of the survey area was assessed and
mapped in accordance with the vegetation condition rating scale for
the South West and Interzone Botanical Provinces (EPA and DPaW
Level and nature of disturbances (e.g. weed presence, fire and time
since last fire, impacts from grazing, exploration activities).
List of dominant flora from each structural layer
List of all species within the quadrat including average height,
number and cover (using a modified Braun-Blanquet scale).
A flora inventory was compiled from taxa listed in described quadrats and from opportunistic
floristic records throughout the survey area.
Vegetation units Vegetation units were identified and boundaries delineated using a combination of aerial
photography, topographical features and field data/observations.
Vegetation units were described based on structure, dominant taxa and cover characteristics as
defined by quadrat data and field observations. Vegetation unit descriptions follow the National
Vegetation Information System (NVIS) framework and are consistent with NVIS Level V
(Association). At Level V, three (or occasionally more) taxa per stratum are used to describe the
association (Executive Steering Committee for Australian Vegetation Information (ESCAVI)
Vegetation condition The vegetation condition of the survey area was assessed and mapped in accordance with the
vegetation condition rating scale for the South West and Interzone Botanical Provinces (EPA
and DPaW 2015). The scale recognises the intactness of vegetation and consists of six rating
levels as outlined in Appendix B.
Flora identification and nomenclature Species well known to the survey botanists were identified in the field; all other species were
collected and assigned a unique collection number to facilitate tracking. All plant specimens
collected during the field assessment were dried and processed in accordance with the
requirements of the WA Herbarium. Plant species were identified by the use of taxonomic
literature, electronic keys and online electronic databases. Where necessary, plant taxonomists
considered to be authorities on particular plant groups were consulted.
6 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
The conservation status of all recorded flora was compared against the current lists available on
FloraBase (WA Herbarium 2016) and the EPBC Act List of Threatened Flora (DotEE 2016b).
Conservation significant flora that could not be confidently identified at the WA Herbarium by the
field botanist were submitted to the WA Herbarium for formal identification (Accession Number:
Nomenclature used in this report follows that used by the WA Herbarium as reported on
FloraBase (WA Herbarium 2016).
Surveys for conservation significant flora Prior to the field survey, information from the desktop assessments (e.g. aerial photography,
geology, soils and topography data, EPBC Act PMST, TPFL and NatureMap) was reviewed to
determine conservation significant flora taxa potentially present within the survey area.
Additionally, ecological information (e.g. habitat, associated flora taxa and phenology) was
sourced from FloraBase (WA Herbarium 2016) and other relevant publications where available,
to provide further details.
Potential habitats were searched for the presence of conservation significant flora. Locations
within the survey area with differing hydrology, fire or disturbance history to the surrounding
areas were also searched where identified.
When any known or potential Threatened, Priority or significant flora was located, the following
data was collected: GPS location, height (m), number of plants and corresponding area of
population, reproductive state and plant condition.
Zoologists (Glen Gaikhorst and Craig Grabham) undertook a single season Level 1 fauna
survey (reconnaissance survey) of the survey area from the 1 to 5 August 2016. The fauna
survey was undertaken concurrently with the vegetation and flora assessment and with
reference to the EPA Guidance Statement No. 56 Terrestrial Fauna Survey for Environmental Impact Assessment in Western Australia (EPA 2004). The purpose of the reconnaissance
survey was to verify the accuracy of the desktop study, and delineate and characterise the
fauna assemblages present in the survey area.
The majority of the survey area was traversed on foot and by vehicle over the course of five
days to identify and describe the dominant fauna habitat types and their condition, assess
habitat connectivity, identify and record fauna species within the survey area. A Likelihood of
Occurrence assessment for conservation significant fauna and their habitats occurring within the
survey area was also undertaken.
Habitat assessment Fauna habitats were assessed in-situ and comprised visual assessment of the following:
Habitat structure (e.g. vegetation type, presence/absence of structural layers such as
ground cover and mid storey)
Presence/absence of refuge including: density of ground covers, fallen timber, hollow-
bearing trees and stags and rocks/boulder piles, and the type and extent of each refuge
Presence/absence of waterways including type, extent and habitat quality within
Location of the habitat within the survey area in comparison to the habitat within the
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 7
Habitat connectivity and identification of wildlife corridors within and immediately adjacent
to the survey area
Current land use and disturbance history
Identification and evaluation of key habitat features and types identified during the
desktop assessment relevant to fauna of conservation significance
Evaluation of the Likelihood of Occurrence of conservation significant fauna within the
habitat (based on presence of suitable habitat and observations)
A representative photograph of each habitat type.
Opportunistic fauna searches Opportunistic fauna searches were also conducted across the survey area. The majority of
opportunistic searches were undertaken at habitat assessment locations and focussed on the
Searching the survey area for tracks, scats, bones, diggings and feeding areas for both
native and feral fauna
Searching through microhabitats including turning over rocks and ground debris (e.g. leaf
litter) and examining tree hollows and hollow logs for reptile and other small vertebrate
Visual and aural surveys. This accounted for many bird species potentially utilising the
survey area The Michael Morcombe eGuide to Australian Birds –
(Morcombe2014) and binoculars were used to assist visual observations. Pre-recorded
calls (Morcombe 2014) were used to assist with aural identification of bird species
A visual assessment of the water bodies to identify any fish species observed
Recording GPS locations of any conservation significant fauna species.
Camera traps Remote sensor cameras (15 x Reconyx-Hyperfire and 5 x ScoutGuard DTC 560K) were
deployed for 15 nights each at 20 locations within the survey area. Cameras were positioned in
areas where key habitat features were present or potential activity of species was recorded.
Cameras were baited with cereal laced with peanut butter and honey to attract fauna. For each
camera location the time and date deployed and recovered, a GPS coordinate, and brief habitat
description were recorded (as seen in Table 2). Camera locations are displayed in Figure 5,
Appendix A. Data from the cameras was downloaded to a computer and analysed for the
presence of animals following the field survey.
Camera trap locations and effort undertaken
6659242 3 Aug
6659348 3 Aug
6660051 3 Aug
6659374 3 Aug
8 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
6656593 3 Aug
On dam edge
6656589 3 Aug
On dam edge
6656519 3 Aug
6656539 3 Aug
6656549 3 Aug
6660127 3 Aug
Kingia Heath on
6659313 3 Aug
Kingia Heath on
6660101 3 Aug
Kingia Heath on
6659278 3 Aug
Kingia Heath on
6659981 3 Aug
Kingia Heath on
6660175 3 Aug
Low Heath with
6660146 3 Aug
Low Heath with
6660119 3 Aug
Low Heath with
6660166 3 Aug
On isolated Rock
6660175 3 Aug
Low Heath with
Banksia Bat survey Two Songmeter SM2BAT+ recorder (Wildlife Acoustics Inc., USA) and one Anabat Express
recorder (Titley Scientific) was deployed at three locations. The three units were deployed for a
combined total of 26 nights to record ultrasonic echolocation calls emitted by microchiropteran
bats. Figure 5, Appendix A displays the detector locations within the survey area.
Data from the detector were downloaded to a computer and analysed for the presence of bat
calls by Craig Grabham of GHD following the field survey (see Appendix E).
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 9
Fauna species identification Fauna species were identified in the field using available field and electronic guides (e.g.
Morcombe 2014). Where identification was not possible, photographs of specimens were
collected to be later identified.
Nomenclature follows that used by the WA Museum (as shown on NatureMap), as it is deemed
to contain the most up-to-date species information for WA, with the exception of birds, where
Christidis and Boles (2008) was used.
Targeted survey for Black Cockatoo The aim of the habitat assessment was to assess the presence, quality and extent of habitat for
Carnaby’s Black Cockatoo
within the survey area based on their modelled distribution
(Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC
Carnaby’s Black Cockatoo
is the only Black Cockatoo in this region with both Forest
tailed Black Cockatoo and Baudin’s Black Cockatoo not modelled to be present
(DSEWPaC 2012a). The survey involved visual and aural assessment of the survey area
identifying breeding habitat (presence/absence of actual and potential breeding trees), foraging
habitat, roosting areas, current activity and any other signs of use by
For the purpose of this assessment, the DSEWPaC (2012a) Black Cockatoo referral guideline
was used to define breeding, foraging and night roosting habitat.
Information collected during the field survey included:
the location and extent of suitable Black Cockatoo species foraging
habitat was identified and mapped for the survey area, based on the vegetation
associations and presence/absence of known foraging species. During the field surveys
any direct or indirect evidence of foraging by Black Cockatoos was recorded via GPS
Breeding habitat - suitable breeding habitat for Black Cockatoos is defined by DSEWPaC
(2012a) as trees of species known to support breeding within the range of the species
which either have a suitable nest hollow or are of a suitable diameter at breast height
(DBH) to develop a nest hollow. For most tree species, suitable DBH is 500 millimetres
(mm). For Salmon Gum and Wandoo, suitable DBH is 300 mm (DSEWPaC 2012a).
Breeding habitat was identified and mapped according to the presence of suitable
woodland habitat. Individual trees for the entire survey area were not mapped however
10 (50 x 50 m) plots were undertaken in Wandoo Woodland and four in Marri Woodland
to ascertain tree densities within these habitats. For each breeding tree, details of the tree
species, size and number of hollows observed, evidence of use and any other significant
observations were recorded. On average, Carnaby’s Black Cockatoos are known to nest
in hollows with an entrance diameter greater than 200-300 mm (Johnstone and Storr
1998; Groom 2011). Therefore, during the field survey a suitable nesting hollow currently
able to support breeding was defined as a tree hollow with an entrance diameter of 200
mm or greater
Night roosting habitat - suitable roosting habitat is defined by DSEWPaC (2012a).
Suitable roosting habitat was identified based on the presence of suitable tall trees,
proximity of known roosting sites and the presence of suitable foraging habitat
Opportunistic observations (both visual and aural) for the presence of Black Cockatoos
within the survey area and surrounding areas were also noted during the survey.
This information was used to map and calculate the amount of foraging habitat, breeding,
potential breeding habitat and night roosting sites within the survey area. Any area containing
known foraging species or potential nesting trees was considered as habitat for Black
10 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
The EPBC Act PMST is based on bioclimatic modelling for the potential presence of species. As
such, this does not represent actual records of the species within the area. The records from the
DPaW searches of Threatened flora and fauna provide more accurate information for the
general area. However, some collection, sighting or trapping records cannot be dated and often
misrepresent the current range of Threatened species.
Field survey limitations
The EPA and DPaW (2015) Technical Guide and Guidance Statement No. 56 (EPA 2004)
states that flora and fauna survey reports for environmental impact assessment in WA should
contain a section describing the limitations of the survey methods used. The limitations and
constraints associated with this field survey are discussed in Table 3.
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 11
Adequate information is available for the survey area; this includes:
Broad scale (1:250,000) vegetation mapping by Beard (1979) and digitised by Shepherd et al. (2002)
Regional biogeography (Desmond and Chant2001)
Regional vegetation (Department of Conservation and Land Management (CALM) 1995; Bell et al. 1984).
Scope (what life
forms were sampled
Vascular flora and terrestrial vertebrate fauna were sampled during the survey. Non-vascular flora, invertebrate
and aquatic fauna were not assessed as part of survey, although opportunistic records were taken of
invertebrate and aquatic fauna during the survey.
Proportion of flora
identified (based on
sampling, timing and
Proportion of fauna
Moderate The vegetation and flora survey was a single season survey only and was undertaken in early August 2016. The
optimal time to undertake flora and vegetation surveys in the Northern Sandplains region is in Spring from
September to November (EPA and DPaW 2015). The majority of the conservation significant flora identified in
the desktop assessment flower from September to October and therefore the survey timing was a little early with
many of the observed species either budding or not in flower. The proportion of flora collected and identified was
considered low for the region; with annuals representing only 6.12 % of species recorded. Orchids represented
only 3.79 % of species while grasses and daisies combined also only represented 4.66 % of species.
The fauna survey was undertaken in early August 2016 and was a reconnaissance survey only. The fauna
assessment sampled those species that can be easily seen, heard or have distinctive signs, such as tracks,
scats, diggings, etc. Twenty remote cameras were deployed for 15 days in Wandoo woodlands and healthlands
to gather additional data on some nocturnal species. Many cryptic (e.g. invertebrate species) and localised
nocturnal species would not have been identified during a reconnaissance survey and seasonal variation within
species often requires targeted surveys at a particular time of the year.
The fauna assessment was aimed at identifying habitat types and terrestrial vertebrate fauna utilising the survey
area. No sampling for invertebrates or aquatic species occurred. Where terrestrial invertebrate fauna was
recorded opportunistically, these findings were mentioned in this report. However, this report is limited to an
assessment of terrestrial vertebrate fauna, as the information available on the identification, distribution and
conservation status of invertebrates is generally less extensive than that of vertebrate species. Flora determination
Moderate Flora determination was undertaken by Mathew Gannaway and Joshua Foster in the field and by Mathew
Gannaway at the WA Herbarium.
Fifty-six taxa could only be identified to genus and nine taxa could only be identified to family due to lack of
flowering and fruiting material required for identification. With no flowering or fruiting material, positive
identification of these collections and their resemblance to conservation significant flora identified in the desktop
assessment could not occur. Additionally, some species, particularly small herbs and annuals were unable to be
identified due to only cotyledons present or insufficient material available for identification.
12 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
The taxonomy and conservation status of the WA flora is dynamic. This report was prepared with reliance on
taxonomy and conservation status current at the time report development, but it should be noted this may
change in response to ongoing research and review of International Union for Conservation of Nature criteria.
further work which
might be needed
(e.g. was the
relevant area fully
The survey area is large (approximately 1993 ha) and was surveyed through the use of a vehicle, surveying only
those areas accessible with vehicle tracks. Information gained from the survey was extrapolated across the
sections of the survey area not easily accessed by vehicle to assist with determining the extent of vegetation
and habitat types for the survey area. As the survey area is in a dynamic landscape with varied low heath
formations that are not easily discernible from aerial imagery, extrapolation of the vegetation and habitat caries
a small degree of uncertainty. In addition, the flora is very complex in the survey area with some species unable
to be distinguished from similar species due to insufficient flowering and fruiting material.
As the survey area is not proposed for clearing but rather for retention as conservation estate, lack of
comprehensive coverage is not a true constraint for this project.
High resolution Environmental Systems Research Institute aerial imagery was available.
Data were recorded in the field using hand-held GPS tools (e.g. Tablet using the Collector Application and
Garmin GPS). Certain atmospheric factors and other sources of error can affect the accuracy of GPS receivers.
The Garmin GPS units used for this survey are accurate to within +/-10 m on average. Therefore the data points
consisting of coordinates recorded from the GPS may be imprecise.
Moderate The field survey was conducted in early August 2016. In the four months prior to the survey (April to July),
Jurien Bay weather station (No. 0091316, Bureau of Meteorology (BoM) 2016) recorded a total of 401.7
millimetres (mm) of rainfall. This rainfall is well above the long term average (LTA) for the same period (April to
July; 328.2 mm) (BoM 2016). While sufficient rainfall was received within the survey area, an assessment of the
flowering times of conservation significant flora taxa shows that September to October is the optimum time to
capture a majority of the conservation significant flora in flower (Appendix D) as plant flowering is linked to both
rainfall and temperature. It was noted during the field survey that a majority of taxa had either just started to bud
or showed no flowering or fruiting material, suggesting the survey was too early to capture flowering times for a
majority of species. In addition, annuals only represented 6.12 % of species recorded.
fire, flood, accidental
The majority of the survey area has been exposed to a mosaic of historical fire regimes with a variety of burn
ages recorded. Most of the disturbances throughout the survey area were associated with historical coal drilling
activity with a number of wells located throughout the northern part of the property, and associated vehicle
tracks. Around the homestead and paddock area pasture species, in particular *Arctotheca calendula was
prevalent. Feral pig activity was noted throughout the survey area, in particular along drainage lines.
retrospect, was the
Moderate The vascular flora of the survey area was sampled in accordance with the EPA and DPaW (2015) Technical
Guide and terrestrial fauna sampled in accordance to EPA (2004a) as required by the scope of works.
The survey area is large (approximately 1993 ha), which meant the survey area could only be covered efficiently
through the use of a vehicle, surveying only those areas accessible with vehicle tracks. Certain areas of the
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 13
survey area were unable to be accurately assessed due to insufficient vehicle tracks and time constraints
limiting the ability to traverse the survey area on foot. Information gained from along the vehicles tracks were
extrapolated across the areas not accessed by vehicle.
Adequate resources were employed during the field survey. Sixteen person days were spent undertaking the
survey using two dedicated botanists and two zoologists (1 botanist and 1 zoologist for five days each and 1
botanist and 1 zoologist for 3 days each).
No access problems were encountered during the survey. The survey area was accessed by vehicle and only
time constraints limited the accessibility of the survey area on foot.
The ecologists who executed the survey were practitioners suitably qualified in their respective fields.
Glen Gaikhorst (zoologist) is a Senior Ecologist with over 20 years’ experience in undertaking ecological
surveys, most of which is undertaking surveys in Western Australia, including projects in the Northern
Sandplains. Craig Grabham (zoologist) is a Senior Ecologist with over 16 years’ experience in undertaking
ecological surveys, including 4 years’ experience undertaking surveys in Western Australia
. Joshua Foster is a
Ecologist (botanist) with over 18 years’ experience in undertaking ecological surveys in Western
Australia, including extensive experience in the Northern Sandplains. Mathew Gannaway is an Ecologist
(botanist) with 8 years’ ex
perience in undertaking ecological surveys in Western Australia, including projects in
the Northern Sandplains.
14 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
The survey area is located in the Northern Sandplains Region of WA and experiences a dry,
warm Mediterranean climate with winter precipitation ranging from 300-500 mm with seven to
eight dry months per year (Beard 1990).
The BoM Jurien Bay station (site number: 009131) is the nearest active weather station to the
study area with continuous long-term data (approximately 20 km south west from the study
area). Climatic data from this site indicates the mean maximum temperature of the area ranges
from 19.5 degrees Celsius (°C) in July to 30.9 °C in February, and the mean minimum
temperature of the area ranges from 9.3 °C in July to 18.0 °C in February. The LTA annual
rainfall is 551.7 mm, with an average of 71.4 rain days per year (BoM 2016).
Rainfall and temperature data for Jurien Bay in the 12 months preceding the survey are
summarised in Plate 1 (BoM 2016). In the four months prior to the survey (April to July), Jurien
Bay weather station recorded a total of 401.7 mm of rainfall. This rainfall total is higher than the
LTA for the same period (April to July; 328.4 mm) (BoM 2016). The weather conditions recorded
during the field survey included (BoM 2016):
Maximum temperature range: 18.0 °C - 21.5 °C
Minimum temperature range: 5.0 °C - 13.0 °C
Rainfall 2.7 mm.
Plate 1 Rainfall and temperature data for Jurien Bay
The survey area is situated in the Southwest Botanical Province of WA (Beard 1990), within the
Geraldton Sandplains Bioregion and Lesueur Sandplain Sub-region as described by the Interim
Biogeographic Regionalisation of Australia (IBRA) (DotEE 2016c).
Te m pe ratu re ( ° C) Rai nfa ll (m m ) Month LTA Rainfall
GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834 | 15
The Geraldton Sandplains Bioregion comprises the central and northern Perth Basin, the
Pinjarra Orogen, and the south end of the Carnarvon Basin. Outcrops of Jurassic siltstones and
sandstones can be heavily lateralised. Extensive proteaceous heaths and scrub-heaths often
with emergent mallees, Banksia and Actinostrobus, occur on an undulating, lateritic sandplain
mantling Permian to Cretaceous strata. These heaths are rich in endemics (CALM 2002).
The Lesueur Sandplain Subregion comprises coastal Aeolian and limestone soils, Jurassic
siltstones and sandstones (often heavily lateralised) of the central Perth Basin. Alluvial soils are
associated with drainage systems. There are extensive yellow sandplains in the south-eastern
parts of the Subregion, especially where the Subregion overlaps the western edge of the Pilbara
Craton. Shrub-heaths rich in endemics occur on a mosaic of lateritic mesas, sandplains, coastal
sands and limestone soils (Desmond and Chant 2001).
Landforms and soils
The survey area is located within the Arrowsmith Zone of the Greenough Province. The
Greenough Province is characterised by a lateritised plateau developed on Jurassic and
Permian sediments and Proterozoic granites; dissected at fringes. There is a narrow coastal
plain with Quaternary sands and calcarenite on the western margin. The Arrowsmith Zone is
characterised by a dissected lateritic sandplain on Cretaceous and Jurassic sediments and is
bounded in the east by the Dandaragan Scarp and in the south and west by the Gingin Scarp.
The sandy and gravelly soils were formed in colluvium and the rock weathered in-situ
(Schoknecht et al. 2004).
The Australian Soil Resource Information System (ASRIS) (2016) mapping indicates that one
soil landscape type occurs within the survey area:
Broad valleys and undulating interfluvial areas; some evenly sloping pediments
with exposure of sandstone and shale. Chief soils are sandy acidic yellow mottled soils,
containing much ironstone gravel in the A horizons and forming a complex pattern with
lateritic sandy gravels. Associated are leached sands underlain by lateritic gravels, and
mottled clays that occur about three feet in depth. Other soils include yellow duplex soils
as well as podzol soils on the pediments; and red duplex soils in areas where country
rock has been exposed.
A summary of the Department of Water (DoW) Geographic Data Atlas (DoW 2016) results for
the survey area is provided in Table 4. The study area is located within the Jurien Groundwater
Area and the Hill River and Tributaries Catchment Surface Water Area as listed under the
Rights in Water and Irrigation Act 1914 (RIWI Act). Munbinea Creek and associated minor
tributaries flow through the western portion of the survey area (Figure 2; Appendix A).
16 | GHD | Report for Main Roads Western Australia - Hill River Offset Property, 61/34834
Department of Water geographic atlas queries for the survey area
Groundwater areas proclaimed under the
Surface water areas
Surface water areas proclaimed under the
Hill River and
Irrigation Districts proclaimed under the
Rivers proclaimed under the RIWI Act.
Public Drinking Water
Source Areas (PDWSA)
PDWSAs is a collective term used for the
description of Water Reserves, Catchment
Areas and Underground Pollution Control
Areas declared (gazetted) under the
provisions of the Metropolitan Water Supply, Sewage and Drainage Act 1909 or
the Country Area Water Supply Act 1947.
Areas proclaimed under the Waterway Conservation Act 1976.
Conservation reserves and estate
There are a number of DPaW-managed conservation areas located within the study area
including: Drovers Cave National Park, Beekeepers Nature Reserve, Hill River Nature Reserve,
South Eneabba Nature Reserve and a number of smaller Crown reserves for the conservation
of flora and fauna. The closest DPaW-managed conservation areas are located immediately
adjacent to the survey area, including the Coomallo Nature Reserve (Class C) to the east and
Lesueur National Park (Class A) to the north. No DPaW-managed conservation areas are
located within the survey area.
Environmentally Sensitive Areas
A number of Environmentally Sensitive Areas (ESAs) are located within the study area, primarily
associated with the presence of TECs and Threatened flora locations. Two ESAs located
adjacent to the survey area include the Coomallo Nature Reserve located to the east and
Lesueur National Park located to the north. A ESA
associated with the TEC ‘
Floristic Community D1
is located within the survey area (Figure 2, Appendix A).
3.5.3 Important bird areas
In a project managed by BirdLife Australia, thirteen Important Bird Areas (IBAs) have been
designated specifically for Carnaby’s Black Cockatoo (Dutson
et al. 2009). IBAs are sites of
global bird conservation importance and are considered a priority for bird conservation. The
criteria used for the designation of IBAs for Carnaby’s Black Cockatoo are sites supporting at
least 20 breeding pairs, or 1% of the population regularly utilising an area in the non-breeding