Vegetation assessment for Seasonal
Herbaceous Wetlands at the ‘Muddy
Gates Lane swamp complex’
June 2014
Introduction
The expansion of Melbourne’s Urban Growth Boundary (UGB) will impact several ‘matters of
national environmental significance’ listed under the federal Environment Protection and Biodiversity
Conservation Act 1999 (EPBC Act). The proposed development and conservation commitments are
set out in the Program Report (DSE 2009). A strategic impact assessment (SIA) (DSE 2009b) under
the EPBC Act led to Commonwealth Government endorsement of the program, approval of a
detailed Biodiversity Conservation Strategy (DEPI 2013a), and approvals for urban development and
related rail infrastructure.
Since the finalisation of the Program Report, a new ecological community was listed under the EPBC
Act: ‘Seasonal Herbaceous Wetlands (Freshwater) of the Temperate Lowland Plains’ (hereafter SHW,
TSSC 2012). In 2013, DEPI conducted an assessment of the likely impact of urban development on
this community (DEPI 2013b). This assessment identified SHW sites known to be of large size or high
quality and discussed their protection.
In September 2013, the Commonwealth Government approved urban development in three of the
four growth corridors, excluding an area of SHW in the northern growth corridor known as Hearnes
Swamp. An approval for urban development in the south-eastern growth corridor was not
considered at that time, pending completion of the revised Sub-regional Species Strategy for the
Southern Brown Bandicoot.
One potentially important SHW site in the south eastern growth corridor could not be accessed and
as such was not addressed by DEPI (2013b). This site, referred to as the ‘Muddy Gates Lane Swamp
Complex’, was highlighted as an area thought to contain approximately 10 ha of high quality SHW.
That assessment was based on informal advice from consultants who were familiar with the area
and aerial photograph interpretation.
In June 2014, access was granted to inspect the site on-ground. This report documents the findings
of that field assessment.
Location and approach
‘The Muddy Gates Lane Swamp Complex’ identified by DEPI (2013) is spread across two parcels of
land at 470 Pattersons Rd (northern parcel of 66 ha) and 1965 Ballarto Rd (southern parcel of 64.5
ha), in Clyde (City of Casey).
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The assessment targeted the areas of the property thought to contain the core area of high quality
SHW (DEPI, 2013b). Advice from ecological consultants suggested that most of the significant
ecological values are located on the northern parcel.
The northern parcel was visited on the 12th June, 2014, for 2.5 hours, by a botanist from DEPI (the
Arthur Rylah Institute) and an officer of the Australian Government Department of Environment. An
assessment was made of the extent of the SHW community, concentrating on the low-lying south
and south-western areas of the northern parcel, where DEPI (2013b) suggested the botanical values
were concentrated. The southern parcel was viewed from over the fence based on advice from
ecological consultants that most of the significant values are located on the northern parcel and the
degraded nature of the land for SHW observed during the site visit.
Findings
Summary
The southern section of the northern parcel that was assessed contains several small patches of
SHW, totalling approximately 0.75 ha. The area of this parcel that was not inspected may contain
additional SHW, but given that area is smaller than the area inspected and includes more elevated
land, it is probable that it contains only small areas of SHW (expected to be <0.75 ha).
The southern parcel was not assessed in detail. It is significantly more degraded than the northern
parcel, supporting a large expanse of introduced pasture. It contained no SHW in the area visible
from over the fence. It is considered highly unlikely that this parcel contains significant areas of
SHW.
Overall, it is considered highly unlikely that the property supports the estimated 10 ha suggested by
DEPI (2013b).
Detailed site notes on the distribution of SHW
For ease of description, the areas that may once have supported SHW on the northern parcel were
divided into 4 zones, each corresponding to distinct condition classes. These are discussed in detail
below and are shown on Figure 1.
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Figure 1. Site map, showing the zones discussed in the text and the likely distribution of SHW on the property.
It also shows the areas that were not viewed during the site visit. (The southern parcel shows the area that
was viewed over the fence). Un-annotated areas do not contain SHW.
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Zone 1:
This area was thought to be the core of the SHW on the property, as described by DEPI (2013).
The area did not support the SHW community. It was dominated by weeds (most abundant were
Paspalum distichum, Poa annua, Trifolium spp., Agrostis capillaris) and native species did not
provide sufficient cover to meet the community definition (TSSC 2012). Native species covered
approximately 5% of the zone. The most abundant were Juncus australis and Lythrum hyssopifolia,
generalist species abundant in degraded wetlands, and not particularly characteristic of SHW. The
area was heavily pugged by cattle and traversed by an excavated drain. Zone 1 is shown in Figures 2
and 3.
It is possible that native species may become more abundant under different hydrological
conditions, however the dominance of the perennial semi-aquatic grass Paspalum distichum makes
it unlikely that native species would increase to levels consistent with SHW (TSSC 2012) without
intensive restoration.
Figure 2. Typical vegetation in zone 1.
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Figure 3. Close up of the ground layer in zone 1, showing dominance by the perennial weed Paspalum
distichum.
Zone 2:
This area did not support SHW. It was similar to Zone 1, except that Juncus spp. contributed
approximately 25% cover. Zone 2 is shown in Figure 4.
Figure 4. Typical vegetation in Zone 2.
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Zone 3:
This area is the lowest-lying part of the northern parcel and consequently the area most frequently
and deeply inundated. It was largely bare mud disturbed by cattle. The vegetation that was present
comprised species identical to those described for Zone 1. Zone 3 is shown in Figure 5.
Figure 5. Zone 3, showing damage by cattle and lack of native vegetation cover.
Zone 4:
Zone 4 covers several separate areas of the northern parcel. This zone supported vegetation
consistent in character with SHW. As a whole, however, the zone did not have sufficient native
cover to meet the criteria for SHW. However, the coverage of native species was uneven and it is
estimated that about 30% of the area covered by zone 4 does meet the criteria for SHW. This
equates to ~0.75 ha across the area examined.
The most abundant native species were all consistent with SHW: Lobelia pratioides (Poison Lobelia),
Centella cordifolia (Centella), Lythrum hyssopifolia (Small Loosestrife), Schoenus apogon (Common
Bog-sedge) and Euchiton collinus (Creeping Cudweed). Several other native species consistent with
SHW were noted at very low abundance (Hemarthira uncinata, Haloragis heterophylla, Eryngium
vesiculsoum, Ranunculus inundatus).
Three of the species observed (Eryngium vesiculosum, Lobelia pratioides, Ranunculus inundatus) are
listed as indicating high-quality SHW (TSSC 2012), demonstrating that any SHW present in zone 4
should be considered to be ‘high quality’.
Weed species made up most of the cover in zone 4, with Agrostis capillaris, Plantago coronopus,
Hypochaeris radicata and Paspalum distichum being the most abundant.
Zone 4 is shown in Figures 6 and 7.
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Figure 6. Zone 4; the largest patch of several.
Figure 7. Some of the species characteristic of SHW observed in zone 4 (left to right: Centella cordifolia,
Lobelia pratioides, Eryngium vesiculosum).
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Potential for SHW in the areas not assessed
The assessment targeted the areas of the property thought to contain the core area of high quality
SHW (DEPI, 2013b). Two other areas were not viewed:

The southern parcel. The northern portion of this area, which was mapped as SHW in DEPI
(2013b) was visible from over the fence. It was equivalent to zone 1, as described in detail
here. It was heavily grazed and pugged, and extensively dominated by introduced pasture
species. The property as a whole appears to be dominated by introduced pasture species. It
is considered highly unlikely that SHW persists on this property in large quantity.

Portions of the northern parcel that were not inspected. These areas may contain some
SHW, however given this portion of the parcel was more elevated than the portion
inspected, and was estimated to contain little SHW in DEPI (2013b), it is probable that it
contains only small areas of SHW (expected to be <0.75 ha).
Other vegetation
The property supported large areas of native grassland, which are almost certainly derived from
grassy woodlands following the clearance of trees. The grasslands occur on undulating terrain, on
soils that range from sandy loams to heavy clays (the latter on the margins of existing or former
SHW). The grasslands were dominated by Themeda triandra (Kangaroo Grass) and Rytidosperma
species (Wallaby Grasses). Among the grasses grew a range of native herbs, including a large
quantity of Leptorhynchos squamatus (Scaly Buttons). Occasional plants of Leptospermum
continentale (Prickly Tea-tree) suggested that the area once supported woody vegetation.
The grassland area was heavily invaded by Ulex europaeus (Gorse), which contributed perhaps 25%
of the cover overall, and in places close to 100%. Despite this high degree of weed invasion, the
grassy layer beneath the gorse was largely native.
These grasslands are not referrable to any community listed under the EPBC Act.
Some areas may be referrable to the ‘Plains Grassland (South Gippsland) Community’ listed under
the Victorian Flora and Fauna Guarantee Act 1988. The description of that community does not
provide information on the geomorphological context or soil types, however it applies to areas on
heavy-soil plains; such that only small areas of the grassland on the property are likely to be
referrable to the listed community (there is currently a nomination under consideration for EPBClisting for a community that is essentially identical to the FFG-listed community).
Significant species
No EPBC-listed, or state-listed species were detected on the property during this assessment.
Anecdotal reports from local naturalists indicate that a population of a Prasophyllum (Leek Orchid)
occurs near the eastern fence-line of the northern parcel. This orchid is likely to be P. frenchii, listed
as endangered under the EPBC Act. It is also possible that the species is an undescribed and very rare
taxon allied to P. diversifolium. This species was not observed during the assessment on 12th June,
however it would be expected to be difficult to detect at the time of the site visit (plant not yet in
flower, or grown to full height) and the lack of observation does not indicate the lack of this species.
Numerous locally significant species were observed.
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References
DSE (2009a) Delivering Melbourne’s newest sustainable communities. Program Report. Department
of Sustainability and Environment (now DEPI), East Melbourne.
DSE (2009b) Delivering Melbourne’s newest sustainable communities. Strategic Impact Assessment
Report. Department of Sustainability and Environment (now DEPI), East Melbourne.
DEPI (2013a) Biodiversity Conservation Strategy for Melbourne’s Growth Corridors. Department of
Environment and Primary Industries, East Melbourne.
DEPI (2013b) The impact of Melbourne’s growth on ‘seasonal herbaceous wetlands (freshwater) of
the temperate lowland plains’: Melbourne Strategic Assessment. Department of Environment and
Primary Industries, East Melbourne.
TSSC (Threatened Species Scientific Committee) (2012) Advice to the Minister for Sustainability,
Environment, Water, Population and Communities from the Threatened Species Scientific
Committee (the Committee) on an Amendment to the List of Threatened Ecological Communities
under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act): Seasonal
Herbaceous Wetlands (Freshwater) of the Temperate Lowland Plains.
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