Yellowish Sedge-skipper Butterfly Reintroduction
Feasibility Project – Final Report
Prepared by Chris Butcher for the Nature Conservation Society of South Australia for the Adelaide and
Mt Lofty Natural Resources Management Board (Samphire Coast Icon Project).
June 2017
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Contents 1 Executive summary ............................................................................................................................................................ 6
2 Introduction .......................................................................................................................................................................... 7
2.1 Overview ...................................................................................................................................................................... 7
2.2 Purpose ........................................................................................................................................................................ 7
2.3 The bigger picture ................................................................................................................................................... 7
2.4 Project deliverables ................................................................................................................................................. 8
2.5 Layout of the report ................................................................................................................................................ 9
3 Focal species ...................................................................................................................................................................... 10
3.1 Gahnia filum (Thatching Grass) ........................................................................................................................ 10
3.1.1 Overview ............................................................................................................................................................... 10
3.1.2 Distribution .......................................................................................................................................................... 11
3.1.3 Conservation status in South Australia .................................................................................................... 11
3.1.4 Preferences and response to impacts ....................................................................................................... 11
3.1.5 The benefits of Thatching Grass sedgelands ......................................................................................... 12
3.1.6 Thatching Grass as part of integrated pest management ................................................................ 13
3.2 Hesperilla flavescens (Yellowish Sedge-skipper) ....................................................................................... 14
3.2.1 Overview ............................................................................................................................................................... 14
3.2.2 Life stages ............................................................................................................................................................ 15
3.2.3 Conservation status .......................................................................................................................................... 17
3.2.4 Impacts to current and potential populations ...................................................................................... 17
4 Donor populations of Yellowish Sedge-skipper .................................................................................................. 19
4.1 Populations across southern Australia .......................................................................................................... 19
4.2 Thatching Grass sites with YSS on southern Yorke Peninsula .............................................................. 19
4.3 Population surveys on southern Yorke Peninsula ..................................................................................... 19
4.3.1 Preliminary survey - January 2017.............................................................................................................. 20
4.3.2 Secondary survey - February 2017 ............................................................................................................. 21
4.3.3 Preferred habitats ............................................................................................................................................. 25
5 Target sites.......................................................................................................................................................................... 29
5.1 Sites of Gahnia filum (Thatching Grass) sedgeland in the northern Adelaide coastal plains .. 29
5.1.1 Site selection options when creating a potential habitat ................................................................. 29
5.1.2 Vegetation associations that benefit Yellowish Sedge-skippers .................................................... 29
5.1.3 Fire as a management tool ........................................................................................................................... 29
5.1.4 Potential YSS habitats in the northern Adelaide coastal plains ...................................................... 30
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5.2 Target Thatching Grass sites as YSS habitats .............................................................................................. 32
5.2.1 Brooks Road Triangle ...................................................................................................................................... 32
5.2.2 Constellation Model Aeroplane Club ........................................................................................................ 33
5.2.3 Kaurna Park Wetland ....................................................................................................................................... 35
5.2.4 Salisbury Greenfields 3 Wetland ................................................................................................................. 36
5.3 High and medium potential habitats of Thatching Grass sedgelands ............................................. 38
5.3.1 Two Wells Golf Club site ................................................................................................................................ 38
5.3.2 Thompson Creek riparian .............................................................................................................................. 39
5.3.3 Windamere site .................................................................................................................................................. 40
5.4 Medium and low potential habitats of Thatching Grass sedgelands ................................................ 41
6 Reintroduction strategy ................................................................................................................................................. 43
6.1 What to collect and from where ...................................................................................................................... 43
6.2 When and how to collect .................................................................................................................................... 43
6.3 How to move them................................................................................................................................................ 44
6.4 Where to move them ........................................................................................................................................... 44
7 Recommendations ........................................................................................................................................................... 46
8 References ........................................................................................................................................................................... 47
9 Appendices ......................................................................................................................................................................... 49
9.1 Appendix 1 ................................................................................................................................................................ 49
9.1.1 Brooks Road triangle ....................................................................................................................................... 49
9.1.2 Constellation Model Aeroplane Club site ............................................................................................... 52
9.1.3 Kaurna Park Wetland site ............................................................................................................................... 54
9.1.4 Salisbury Greenfields Stage 3 wetlands site ........................................................................................... 56
9.1.5 Two Wells Golf Course site............................................................................................................................ 58
9.1.6 Thompson Creek riparian site ...................................................................................................................... 60
9.1.7 Windamere site (Buckland Park) ................................................................................................................. 62
9.2 Appendix 2 ................................................................................................................................................................ 64
9.2.1 Corny Point Swamp – north .......................................................................................................................... 64
9.2.2 Daly Head Swamps ........................................................................................................................................... 67
9.2.3 Balaklava Road site ........................................................................................................................................... 69
9.2.4 Orrie Cowrie Road site .................................................................................................................................... 71
9.2.5 Old Saltworks Road .......................................................................................................................................... 73
9.2.6 Little Moldarby Waterhole ............................................................................................................................ 75
9.2.7 Brutus Road site - north ................................................................................................................................. 77
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9.3 Appendix 3 ................................................................................................................................................................ 79
9.4 Appendix 4 ................................................................................................................................................................ 80
9.4.1 Data sheets .......................................................................................................................................................... 80
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1 Executive summary
The Yellowish Sedge-skipper Butterfly Reintroduction Feasibility Project assessed several factors that
will aid the return of this native species to its former range on the northern Adelaide coastal plains.
This report presents the status of a focal species, Hesperilla flavescens (Yellowish Sedge-skipper), and
its habitat, Gahnia filum (Thatching Grass) sedgelands. These sedgelands were assessed on the
southern Yorke Peninsula and the northern Adelaide coastal plains.
The Yellowish Sedge-skipper (YSS) is now regionally extinct in the northern Adelaide coastal plains
and extensive habitat restoration work has been done. The purpose was to determine the feasibility of
translocating a suitable form of the YSS from healthy populations on southern Yorke Peninsula to
restored habitats in the northern Adelaide coastal plains.
Feasibility was determined through literature review, desktop analysis, stakeholder engagement,
fieldwork, and data analysis. A literature review determined current knowledge and best practices for
butterfly conservation/reintroduction. Fieldwork included liaising with land managers, surveying
populations of YSS on southern Yorke Peninsula, and detailed descriptions of their habitats (see
appendices). This knowledge was then cross-referenced against potential YSS habitats containing
Thatching Grass tussocks on the northern Adelaide coastal plains. These sites were also surveyed and
described in the report and appendices.
The report concluded that the YSS populations on southern Yorke Peninsula are most likely to be a
suitable form of the species and further research can confirm this (e.g. DNA analysis). Furthermore,
these populations can sustain collection for a translocation. There are at least five sites that host large
populations and many more sites with smaller populations. Each of these sites could sustain some
level of collection. Site assessments also determined that given the correct preparation there are at
least four potential YSS habitats in the northern Adelaide coastal plains that could receive a founding
population of YSS. Three more sites have potential to be YSS habitats given more time and/or more
intensive management.
Recommendations presented in this report include strategies to:
- prepare key reintroduction sites as YSS habitats
- collect, transport and release specimens of YSS from southern Yorke Peninsula to northern
Adelaide coastal plains
- promote YSS reintroduction and Thatching Grass sedgeland restoration for their roles in:
- increasing native biodiversity
- improving visual amenity for nature lovers
- integrated pest management (horticultural pests).
The report also concluded that the assessment had some limitations. It was not able to provide an
accurate population estimate of YSS on southern Yorke Peninsula. This was due the lack of resources
to survey the vastness of the YSS habitats in the region. Despite not arriving at an accurate estimate,
the survey was able to conclude that there were many (several large) healthy YSS populations on
southern Yorke Peninsula.
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2 Introduction
2.1 Overview
A species of butterfly, Hesperilla flavescens flavia (Yellowish Sedge-skipper), has been selected as a
focal species of a landscape-scale recovery project, the Samphire Coast Icon Project. The Yellowish
Sedge-skipper (YSS) uses the sedge species Gahnia filum (Thatching Grass) to lodge its eggs; larvae
once hatched then use the sedge for food and shelter until adult butterflies emerge.
The YSS has a historic coastal or supratidal range between West Beach and St Kilda in the extended
Adelaide coastal plains (Common and Waterhouse, 1972). It has not been sighted in this area since
1985 (ALA, 2015), though populations of the species are known to exist on southern Yorke Peninsula,
west of Adelaide’s Fleurieu Peninsula. It is believed to be regionally extinct from the Adelaide coastal
plains (Coleman and Coleman, 2000; Grund, 2003, New and Sands, 2004; Coleman, 2015).
The YSS relies almost exclusively on Thatching Grass to lay eggs (the larvae then feed on the leaves
after hatching) and perform mating displays. Thatching Grass, though not threatened on a national or
state scale, is rare in the project area.
The main causes of the regional extinction are related to habitat destruction/clearance for primary
production, altered hydrology, the widespread use of aerial pesticide application on horticultural land
adjacent coastal sedgelands and broader mosquito control in the coastal plain.
A 2000 Local Recovery Plan for the YSS (Coleman and Coleman, 2000) outlined and implemented
steps to facilitate reintroducing the butterfly. The plan received strong community support and
resulted in widespread planting of Thatching Grass in the north Adelaide plains project area. This
project has assessed previous work, undertaken additional research and evaluated further work
needed to reintroduce the butterfly.
The project aligns with the Samphire Coast Icon Project (SCIP), which in turn took actions from the
Metropolitan Adelaide Northern Coastal Action Plan (MANCAP). This feasibility project is a
collaborative effort between The Nature Conservation Society of South Australia, Natural Resources
Adelaide and Mount Lofty Ranges, and Bird Life Australia.
2.2 Purpose
The purpose of the project is to determine if it is feasible to reintroduce the YSS into the northern
Adelaide coastal plains within the Adelaide and Mount Lofty Ranges northern coastal region. The
project will also aim to determine the status of YSS populations on Yorke Peninsula and the status of
Thatching Grass sedgelands in the northern Adelaide plains.
2.3 The bigger picture
Since the initial 2000 recovery plan, a great deal of work has been done, through several projects,
plans, and studies that have been working towards a simple goal. Ultimately, the goal is to restore and
expand Thatching Grass sedgelands, the habitat of the YSS, to a condition that can support
reintroduction and successful generations of this butterfly. Large populations of the YSS exist on
southern Yorke Peninsula that appear to be suitable sources for translocation to selected sites within
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the northern Adelaide coastal plains Figure 1. This report outlines recommendations to begin this
process.
The benefits of restoring the YSS habitats are many and are not limited to the reintroduction of the
regionally extinct species. The benefits of expanding Thatching Grass sedgelands range from
ecological, social, and economic. The benefits to each of these are explained in detail in the sections
below (section 3.1.5).
Figure 1: A conceptual diagram of the translocation of Hesperilla flavescens
(Yellowish Sedge-skipper) from surveyed large populations on southern Yorke
Peninsula to target habitats within the project area of the northern Adelaide coastal
plains.
2.4 Project deliverables
The means to measure the success of this project were set a series of deliverables. These deliverables
included a literature review that explored what was known about Yellowish Sedge-skippers, Thatching
Grass, their ecologies, and other related research. This review was completed in late 2016 and provides
a detailed review of both focus species including their current distribution, life stages, habitat
preferences, and phenology (Butcher, 2016).
The status of the Thatching Grass sedgelands that exist in the northern Adelaide coastal plains have
been surveyed and presented (Appendix 1). This survey was a vital step in determining if there are
suitable habitats to which to bring the YSS. Similarly, the populations of YSS on southern Yorke
Peninsula were surveyed in early 2017. Details of key sites were recorded on data sheets (Appendix 2)
and key findings have been analysed and synthesised (section 4.3). The results of this survey gave an
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indication of the population sizes on southern Yorke Peninsula but it also showed the preferred
conditions and habits of the YSS.
With a good understanding of the potential donor populations and the habitats to which they would
be translocated, the next step was determining the best way to do this. It was determined that
reintroduction would be best achieved by translocating the larvae of the YSS (Alex Stolarski, pers.com.
2017). The next step was determining how many larvae and to where they would be translocated
(section 5).
It was important to inform and involve officers from state and local governments because they are in
excellent positions to promote native conservation and revegetation efforts within their fields of
influence. Two presentations were held to keep these officers informed and this generated good
interest from those involved in revegetation work. Landholders and other stakeholders have been kept
informed about the progress of the project and stakeholders of the key reintroduction sites are
supportive of the project. Two public talks were given and members from volunteer groups, nature
lovers, and local stakeholders were invited. Publications have been prepared about the project, the
proposed reintroduction of YSS into Thatching Grass sedgelands, and the potential benefits to pest
management strategies; they distributed to key stakeholders
Some of the areas identified as key reintroduction habitats are on land that can have some degree of
legislative protection. Some sedgelands are close to a drainage line and may fall under the
management of a drainage reserve; however, this will need further exploration.
2.5 Layout of the report
This report draws from all the research and investigations done for the project, including the literature
review and both field survey reports. It will introduce the two focal species, describing attributes
relevant and useful for this project (section 3).
Two of the main aspects of this project were to establish if 1) there are suitable populations of YSS to
reintroduce into the northern Adelaide coastal plains and 2) are there suitable habitats into which they
can be translocated (sections 4 and 5 respectively). A management strategy for each site and
timeframes for reintroduction have also been presented.
A strategy to reintroduce the YSS into the northern Adelaide coastal plains has been developed
including collection and translocation methods, founding population sizes, translocations sites, and
timeframes (section 6 and 7).
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3 Focal species
3.1 Gahnia filum (Thatching Grass)
3.1.1 Overview
The Gahnia sedgelands of southern Australia occur in a variety of conditions but they are commonly
associated with wetland or floodplain systems. From the Cyperaceae family, Gahnia sedgelands are
comprised of several species of Gahnia, grasses, herbs and scattered flowering trees (e.g. Melaleuca,
Banksia, and Eucalyptus). These sedgelands form important habitats for native Hesperiidae (skippers),
provide shelter for some rare migratory birds and (in standing water) a resting platform for waterfowl
(Relf and New, 2009), and a habitat for a range of other animals.
One species of Gahnia sedge, G. filum (Labill.) F.Muell, is the main food plant for the larvae of
Hesperilla flavescens flavia. Gahnia filum is a tussock forming perennial sedge (Figure 2). Common
names for the plant include Thatching Grass, Chaffy Saw-sedge, Smooth Cutting-grass, and Salt
Cutting-grass (Coleman and Coleman, 2000; City of Salisbury, 2010).
Figure 2: Healthy and mature tussocks of Gahnia filum (Thatching Grass) showing the
brown flower heads at Minlacowie Swamp. Photo: Chris Butcher in January 2017.
Thatching Grass is a relatively slow growing and long-lived sedge that flowers from spring to summer
(Wilson, 1993; Wood and Coleman, 2016). The flowering heads rise above the tussock and are a dark
reddish-brown (Coleman and Coleman, 2000). It grows between 60 and 110 centimetres in height
ranging from individual tussocks to a dense monospecific sedgeland.
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3.1.2 Distribution
It is a coastal sedge that grows in mildly saline, supratidal open coastal and near-coastal swamps (New
and Sands, 2004; Coleman, 2015). In south eastern Australia, it spans from the west coast of Eyre
Peninsula across southern South Australia and Victoria, south to Tasmania, and in scattered sites in
southern coastal New South Wales (Figure 3).
Figure 3: Records of Gahnia filum since 1990 range from Eyre Peninsula, SA to Sydney,
NSW, and Tasmania (ALA, 2015).
Coleman (2015) reported a doubling in Gahnia filum numbers since a 2000 local recovery plan was
implemented in the project area (Coleman and Coleman, 2000). There are now over 8,600 plants at 75
individual locations.
3.1.3 Conservation status in South Australia
Thatching Grass does not have a conservation status at state level (Kraehenbuehl, 1993, 1996),
however it is recognized as being Vulnerable in the Adelaide and Mount Lofty Ranges and Near
Threatened in the Yorke Peninsula region (Gillam and Urban, 2014).
3.1.4 Preferences and response to impacts
Thatching Grass is a resilient sedge. It can survive grazing, slashing, and low intensity fire. In fact, fire
has been recognised as an effective way to trigger new growth, which is preferred by the YSS for egg
laying and grazing (larvae). This is in contrast to slashing, which did not trigger significant new growth
(Relf and New, 2009). Once the plant is established it does not require pruning or slashing, though it
can tolerate it. It can prevent weed incursion, control soil erosion and rising salinity, and can stand for
many decades without ‘lodging’ or lying down (Wood and Coleman, 2016).
It can be cultivated in a variety of ways. The common methods are: use mature seed stored for 12
months, use fresh seed and treat with dilute sulfuric acid or smoke water, or thoroughly scarify very
fresh seed (Ralph, 1994 and Southern Native Plant Nursery, pers.com. 1999; cited in Coleman and
Coleman, 2000). The City of Salisbury’s nursery has been successfully propagating Gahnia filum from
seed for several years, using bog propagation methods (cited in Coleman and Coleman, 2000).
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Thatching Grass is capable of surviving in a diverse range of hydrology, salinity and soil types. It can
withstand brackish water, however it thrives in wetlands where the water table is fresh and less than
one and a half metres below the surface (Grund, 2003). Having the ability to tolerate freshwater
inundation and drying out over summer months, Thatching Grass is well suited to the Mediterranean
climate of northern Adelaide coastal plains (Wood and Coleman, 2016).
Although tolerant of salt, Thatching Grass and saltmarsh communities will be sensitive to sea level
change. Significant changes to these communities over the next 100 years will occur if sea level rises
0.3 metres or more as predicted (Caton et al., 2009).
3.1.5 The benefits of Thatching Grass sedgelands
Restoring the Thatching Grass habitat for the YSS will make it possible to reintroduce a regionally
extinct species to its former range. Many other benefits to this action affect regional ecosystems, local
communities and the economies that they generate. The northern Adelaide coastal plains are a major
horticultural district producing most of the State’s fresh produce. Thatching Grass is being explored as
part of an integrated pest management solution. This is discussed as an economic benefit below.
3.1.5.1 Ecological
Increasing the area of the Thatching Grass sedgelands will not only benefit the YSS but it will increase
the habitat for other insects, spiders, reptiles, amphibians, birds (including migratory birds), and small
mammals. This will increase the native biodiversity, which increases the number of ecologic processes
and improves environmental health. A healthy environment is generally more resilient against
environmental stresses and can recover quickly after events such as flood, fire, disease, or drought.
3.1.5.2 Social
Improving the visual amenity and increasing native wildlife will attract more nature lovers to the
region (e.g. hikers, cyclists, kayakers, bird watchers), which will support local communities. There are
areas within the northern Adelaide coastal plains that are adjacent the Adelaide Dolphin Sanctuary
that will be included in the newly proclaimed Adelaide International Bird Sanctuary National Park -
Winaityinaityi Pangkara (Appendix 3). The national park is on land suitable for shorebirds on the tidal
flats north of Adelaide. Thatching Grass sedgelands exist further inland but often close to these areas.
The sanctuary is already being promoted as a bird watching hotspot and has the protection and
management offered by a National Park. If YSS habitat restoration continues and successful
reintroduction of the skipper is achieved, the area can be promoted as a butterfly hotspot too.
Habitats could be used as an education tool for students learning about life sciences. Fieldtrip to these
outdoor classrooms could be used as part of the school curriculum at different levels.
Involving and engaging the community in conservation efforts will instil a sense of ownership and
promote environmental stewardship in the northern Adelaide coastal plains. If more members of the
community are involved in nature conservation then local and state governments will respond with
more projects directed at improving the state of local ecosystems promoting a ‘clean and green’
image, which in turn will facilitate greater change and a greater outcome for the community. This is in
line with the Government of South Australia’s ‘Healthy Parks Healthy People South Australia’ strategy
for 2016-2021. A core principle of this strategy is that ‘Healthy environments are critical for our
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physical, mental, social, and spiritual health; and parks conserve healthy environments for present and
future generations’
3.1.5.3 Economic
There is potential for eco-tourism to be developed in restored habitats of the region, with walking and
cycling trails, as part of a long-term goal. However, by far the greatest potential economic benefit for
the region relates to the control of pests; this is explained in the section below.
3.1.6 Thatching Grass as part of integrated pest management
Horticulturalists lose millions of dollars every year to pests. Pests are costing local growers dearly
either through money lost due to damaged crops or money spent trying to reduce the damage (e.g.
pesticide). One of the most costly pests is the Frankliniella occidentalis (Western Flower Thrip - Figure
4), which damages crops directly through herbivory. The thrip also transports the Tomato Spotted Wilt
Virus, which does greater damage to the crops. Crops affected by this virus include tomato, eggplant,
potato, lettuce, cucumber, and melons (Wood and Coleman, 2016).
The Western Flower Thrip is very small and is transported easily by the wind. They are known to build-
up and ‘over-winter’ on weeds species in and surrounding paddocks, which allows both the thrip and
virus to persist between crop harvests (Wood and Coleman, 2016).
Figure 4: A close up photo of Frankliniella occidentalis (Western Flower Thrip) this
insect is 1-2 mm long and a major pest for horticulturalists in the northern Adelaide
coastal plains. Photo: Lyle Buss.
Thatching Grass sedgelands are known to play an important role in integrated pest management, as
they are host predatory and parasitic insects that target thrips. A study revealed that these insects,
Ceranisus menes (Eulophid Wasp) and Telenomus spp. (Scelionidae Wasps), can be used as a
biocontrol agent that have no known negative impact on crops. Furthermore, Thatching Grass is not
attractive to the thrip like weed species are. Over a four month study, the numbers of Western Flower
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Thrips associated with Thatching Grass were very low compared to the control traps located in nearby
weed infestations (Wood and Coleman, 2016).
Horticulturalists that adopt Thatching Grass as part of an integrated pest management solution could
save a great deal of money. A detailed account of the interaction between beneficial insects and pest
with native vegetation planted near crops can be found in report by the Rural Industries Research and
Development Corporation (2011), and Wood and Coleman (2016).
3.2 Hesperilla flavescens (Yellowish Sedge-skipper)
3.2.1 Overview
There are two subspecies of Hesperilla flavescens (Yellowish Sedge-skipper) and they are H. f. flavia
Waterhouse and H. f. flavescens Waterhouse. They fall under the Hesperiidae family of Lepidoptera
order of insects. H. f. flavia historically populated the Adelaide coastal plains and now viable
populations exist on lower Yorke Peninsula (Figure 5). Hesperilla f. flavescens is a distinct subspecies
found in Altona, west of Melbourne, Victoria (Relf and New, 2009). Adult skippers of the Adelaide
subspecies have very similar morphology to Hesperilla donnysa (Donnysa Skipper) but differ in the
male genitalia and larval food preference (Common and Waterhouse, 1981). Furthermore, H.
flavescens have paler wings with and extensive yellow suffusion of colour on the wing upper sides than
H. donnysa (Common and Waterhouse, 1972; Braby, 2000; Grund, 2003).
Skippers can appear similar to moths in several ways. Skippers generally have duller and shorter wings
than butterflies that may remain open with front wings and rear wings at different angles when
resting, similar to a moth but not flat or pitched. Behaviourally, most skippers and butterflies are active
only during the day (some are active at dusk), whereas most moths are active at night (but many are
diurnal). Upon closer inspection, skippers, like butterflies, have an ‘eyelash’ club or hook at the end of
their antennae, unlike the feathery comb of moths. The front and rear wings of most moths are
connected by a frenulum; all but one species of known skippers and butterflies do not have a
frenulum (Britton, 2015).
A much more detailed analysis on the phylogeny of Papilionoidea and Hesperioidea (butterflies and
skippers) was made by James Scott (1984). This paper gives a much greater historic analysis of the
phylogenetic trees of skippers and butterflies.
Field surveys have revealed that there are healthy populations of YSS at various sites on Yorke
Peninsula. Some reports tell of populations on lower Eyre Peninsula, around Lake Alexandrina and
Lake Albert, Hindmarsh Island, and the Coorong National Park (Grund, 1997; New and Sands, 2002,
2004; Alex Stolarski pers.com. December 2016).
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Figure 5: Mature Hesperilla flavescens (Yellowish Sedge-skipper) reared in controlled
conditions from a pupa collected on southern Yorke Peninsula, SA in February 2017.
3.2.2 Life stages
Yellowish Sedge-skippers follow the same growth and development stages as typical butterflies.
Mature females lay eggs (fertilised by males) which hatch to larvae. The larvae grow through
development phases or instars before entering pupation. During pupation, they go through
metamorphosis and emerge as a mature butterfly. The whole process for larvae to mature, pupate,
and emerge will take almost a year (Common and Waterhouse, 1981).
3.2.2.1 Egg laying
Females select Thatching Grass to lay their eggs (Figure 6), preferring the outer leaves of younger
tussocks (Grund, 2003; New, 2011). Caterpillars of both skipper subspecies create shelters in the leaves
and feed almost exclusively on Thatching Grass. However, H. f. flavescens has been seen feeding on G.
radula and H. f. flavia on G. deusta (Grund, 2003; Alex Stolarski pers.com, December 2016). Gahnia
tussocks age, they become increasingly unsuitable for caterpillars, and the surveys by Savage (2002)
suggested that caterpillars were most common on tussocks around one metre tall and with few dead
leaves.
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Figure 6: An egg of a Hesperilla flavescens (Yellowish Sedge-skipper).
Photo: Ken Walker, 2013.
3.2.2.2 Larvae
Larvae emerge from eggs after about three weeks and spin Thatching Grass leaves together with silk
to create a shelter (Common and Waterhouse, 1972; Relf and New, 2009 - Figure 7). They shelter
during the day and feed on the leaves at night. Larger shelters are constructed as the caterpillars grow
through five instars, the final instar being about seven centimetres long (Relf and New, 2009). A large
shelter or larvae on a tussock and the absence of smaller shelters suggests that caterpillars can
transfer between tussocks; assuming the smaller shelters were not destroyed (e.g. larger grazing
animals) (Relf and New, 2009).
Figure 7: A shelter (red oval) woven by a Hesperilla flavescens (Yellowish Sedge-
skipper) caterpillar between young Gahnia filum (Thatching Grass) leaves. Photo:
Chris Butcher, 2017.
3.2.2.3 Adult skippers
Mature YSS emerge fully grown with a wingspan of 30-40 millimetres (Coleman and Coleman, 2000 -
Figure 8). Skippers fly very quickly (Relf and New, 2009; Alex Stolarski pers.com. December 2016) and a
‘flight’ happens as a mass emergence from the pupae when they will fly together (Grund, 2003). They
generally only fly on a fine sunny day and will avoid flying on cold, cloudy, rainy, or very windy days
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(Grund, 2003). There are two distinct broods laid each year that lead to most of the adults going ‘to
wing’ from September to November and March to April (Common and Waterhouse, 1972; Coleman
and Coleman, 2000).
The spring brood of adult skippers are known to feed on the nectar of flowering Eucalyptus spp.,
Bursaria spinosa (Sweet Bursaria), Melaleuca halmaturorum (Salt or Swamp Paper-bark), Myoporum
insulare (Common Boobialla), Nitraria billardierei (Nitrebush), and other flowering herbs. The autumn
brood tend to rely on the seasonally flowering M. lanceolata (Dryland Tea-tree) and other flowering
herbs (Grund, 2003; Coleman, 2015).
New colonies of skipper have been found up to 500 metres from original translocation sites,
suggesting a minimal range for natural dispersion of the species once reintroduced (Savage, 2002;
cited in Relf and New, 2009).
Figure 8: Adult Hesperilla flavescens flavia (Yellowish Sedge-skipper) from the top
(left) and its underside (right). Photo: Chris Butcher.
3.2.3 Conservation status
The Yellowish Sedge-skipper is not currently listed in the Environment Protection and Biodiversity
Conservation Act 1999 national list of threatened species, ecological communities, and threatening
processes. Similarly, according to the threatened species schedules of the National Parks and Wildlife
Act 1972 (last review in 2008), insects (including butterflies) do not have a current legal conservation
status in South Australia (Coleman and Coleman 2000; DEWNR, 2014).
A classification for conservation concern for butterflies has been prepared by the national Natural
Heritage Trust (New and Sands, 2002). In 2004, both subspecies of Hesperilla flavescens were classed
as Vulnerable in their respective states. Hesperilla f. flavia was previously ranked as Critically
Endangered in South Australia, due to its absence from its former range. However, this classification
has been lowered in SA to Vulnerable owing to the discovery of populations on Yorke Peninsula, and
potentially on Eyre Peninsula and the Coorong National Park (New and Sands, 2004).
3.2.4 Impacts to current and potential populations
It is believed that, along with habitat loss, spray drift from aerial weed control, mosquito control and
pesticide application are major contributor to the skippers’ demise in the northern Adelaide plains.
Fortunately, through increased use of greenhouses, the amount of spray drift has been greatly
reduced in recent years.
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Impacts to the YSS are closely tied to what affects Thatching Grass health. They are listed here:
- Dense grasses growing around the base of Thatching Grass limit the ability of the YSS to
locate their preferred outer leaves on which they lay eggs. The use of plastic guards for the
purpose of grazing protection for the plant may have this same undesired effect (Relf and
New, 2009)
- Grazing by livestock and kangaroos of the exotic plants around the tussock may reduce
competition and allow females better access for oviposition. However continued grazing
threatens the egg and larval stages of the skippers’ development by eating or trampling the
leaves on which they reside (Coleman, 2000 in: Relf and New, 2009).
- Fire of sufficient intensity can destroy eggs and caterpillars. Fire’s ability to trigger the new
growth preferred by skippers in Australian and North America is well documented (COSEWIC,
2003; Relf and New, 2009). However, control burns, if used, must be carefully planned as to
compliment the skipper’s life cycles. For example, burning can benefit the YSS if done on a
mosaic early spring burn of no more than half of the site, two to three weeks after the
beginning of the adult flight season, between peak butterfly emergence and most oviposition.
The benefit would be through an increase in Thatching Grass shoots and nectar plant flowers
(Coleman and Coleman, 2000; Dana, 1991; Relf and New, 2009).
- A drained Gahnia sedgeland will not regenerate as quickly as a wetter site. Sites have been
drained to better suit the growing requirements of crops and pasture. The change in soil
hydrology reduces the number of young leaves/tussocks leaving a greater number of older,
hard and senescing plants, which the YSS avoid (Coleman and Coleman, 2000).
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4 Donor populations of Yellowish Sedge-skipper
4.1 Populations across southern Australia
Populations of YSS occur in small patches across southeastern Australia. Distribution of the YSS is
heavily dependent on the presence of a healthy Gahnia sedgeland (G. filum or G. deusta) and suitable
nectaring plants. Their populations are now recognised to be from southern Eyre Peninsula, southern
Yorke Peninsula, around lakes Alexandrina and Albert in South Australia, and in isolated patches
between Horsham and Altona in Victoria.
It is generally accepted that Hesperilla f. flavia is extinct from its former region of the Adelaide coastal
plains (Coleman and Coleman, 2000; Grund, 2003; Sands and New, 2004; Caton et al., 2009). Field
surveys have revealed that there are healthy populations of YSS at various sites on Yorke Peninsula.
Some reports tell of populations on lower Eyre Peninsula, around Lake Alexandrina and Lake Albert,
Hindmarsh Island, and the Coorong National Park (Grund, 1997; New and Sands, 2002, 2004; Alex
Stolarski pers.com. December 2016).
4.2 Thatching Grass sites with YSS on southern Yorke Peninsula
Butterfly specialists consider the populations of YSS on southern Yorke Peninsula to be in relative
abundance and are likely to be a close genetic match to the regionally extinct form in the northern
Adelaide coastal plains. The Thatching Grass sedgelands of southern Yorke Peninsula were surveyed
by Butterfly Conservation SA in 1999 and 2003 to document their location along with the presence or
absence of the YSS (Grund, 2003). The post-2000 survey revealed a fairly even split of Thatching Grass
sites with and without YSS, although most of the sites without YSS were between Yorketown and
Minlaton (Figure 9). The sites with YSS were in wetlands within 15 kilometres of Warooka and at sites
scattered near the coast to west and south of Warooka. These surveys were the basis of the
population surveys done in this project.
4.3 Population surveys on southern Yorke Peninsula
In order to determine if translocation of YSS is feasible, it was necessary to determine the extent and
abundance of YSS populations on southern Yorke Peninsula. Two surveys were conducted; the first
was in January 2017 and it was to determine the presence and absence of YSS at populated sites
reported in the 2003 survey by Butterfly Conservation SA (Figure 9). The January survey was also to
select sites for a more detailed site survey; sites that were large enough to support a population from
which a sample could potentially be taken.
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Figure 9: Sites of potential Hesperilla flavescens populations. Map taken from "The
yellow sedge-skipper on Yorke Peninsula" by Roger Grund, 2003.
4.3.1 Preliminary survey - January 2017
The January survey team visited 42 sites during the survey and concluded eight sites merited a
population survey (Figure 10). The basis of this decision was that there were YSS present on site and
the site appeared to be large enough to support a large population of YSS. Three more sites showed
potential and would be surveyed given enough resources. These sites could also act as donor
populations to increase genetic diversity. Most of the sites visited can be seen in Figure 11 below.
Site name Latitude / Longitude Easting / Northing Revisit?
Brutus Road sites -34°56’35.3” / 137°19’33.2” 712407.8 / 6130792.5 Yes, major survey
Orrie Cowrie Road site -35°0’32.3” / 137°20’34.1” 713783.1 / 6123453.9 Yes, major survey
Corny Point Swamp -34°55’48.5” / 137°2’51.6” 687024.8 / 6132789 Yes, major survey
Balaklava Road site -35°1’48.1” / 137°20’47.3” 714062.3 / 6121109.7 Yes
Daly Head Swamp -35°1’47.1” / 136°58’18.5” 679876.4 / 6121881.5 Yes
Old Saltworks Road site -35°3’22.9” / 137°26’58.9” 723408.3 / 6117962.4 Yes
Gum Tree Road site -35°3’27.3” / 137°25’37.6” 721344.9 / 6117876.3 Yes
Little Moldarby Waterhole -35°2’50.7” / 137°25’11.7” 720716.2 / 6119022.3 Yes
Diagonal Road site (north of 5-way) -34°57’52.1” / 137°19’17.6” 711956.5 / 6128436.5 Potential
Yorke Highway site -34°57’39.8” / 137°24’4.2” 719235.8 / 6128643.3 Potential
Tea Tree Swamp -35°9’41.8” / 137°14’24.9” 704041.9 / 6106735.6 Potential
Minlacowie Swamp -34°53’42.9” / 137°30’50.8” 729733.5 / 6135688.7 Low priority
Warooka dump site – north of dump site -34°58’51.8” / 137°25’18.9” 721077.8 / 6126378 Low priority
Moorowie Station Road -34°58’27.8” / 137°27’54.2” 725040.3 / 6127021 Low priority
Coutts Lagoon -34°55’52.8” / 137°11’8.6” 699634.8 / 6132391.2 Low priority
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Site name Latitude / Longitude Easting / Northing Revisit?
Corny Point Road site (near Granite Rock) -34°55’28.7” / 137°6’28.3” 692536.1 / 6133287.1 Low priority
Tea Tree Road site -35°13’27.1” / 136°58’4.6” 679100 / 6100320.5 Low priority
Figure 10: Summary table of Gahnia sp. sedgelands on southern Yorke Peninsula
visited in January 2017. “Revisit?” refers to returning to the site for a population
survey. This relates to the presence of Hesperilla flavescens and the potential for a
large population from which to sample. Only sites with potentially viable donor
populations are listed.
Figure 11: Waypoints in the January 2017 survey area of southern Yorke Peninsula,
South Australia. Waypoints represent a site where the survey team found a Hesperilla
flavescens larvae or a recently active shelter, or considered the site ‘of interest’ for
future investigation. Not all sites that were visited received a waypoint.
4.3.2 Secondary survey - February 2017
4.3.2.1 Survey overview
The purpose of this trip was to survey the populations of Yellowish Sedge-skipper (YSS) at key sites on
southern Yorke Peninsula. The main aims were the following:
1. Assess the populations of YSS at selected sites on southern Yorke Peninsula.
2. Extrapolate the results to get an estimate of the extent of populations of YSS and the density
of their shelters on southern Yorke Peninsula.
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3. Determine if the populations are large enough to support the collection of larvae for a
potential reintroduction project.
4. Make recommendations about the location and sample collection density suitable for each
site.
The February 2017 survey team surveyed seven sites on southern Yorke Peninsula. All of the sites
categorised as worthy of a revisit were revisited (Figure 10), with the exception of the Gumtree Road
site, which was could not be surveyed due to time restrictions (Figure 12).
Figure 12: Sites visited during a Yellowish Sedge-skipper population survey in
February 2017. Most sites were located within 15 kilometres of Warooka, near the
centre of the map.
Prior to the survey, using the information from the first site visit, my impression was that there were at
least three primary sites, five secondary and three potential sites that offered large populations that
could be used to populate a founder population without significantly impacting the source
population(s). This view was not changed after the population survey in February.
The take home message from this survey is that each site appears to be able to support larval
collection but further survey and analysis is required to land on a suitable find/collect ratio (e.g. 5:1 –
for every five larvae found, collect one).
4.3.2.2 Survey method
To survey the population the survey team searched for the shelters made by larvae. This was chosen
as the best way because YSS eggs are too small to find quickly, mature YSS are rarely seen, and the
larvae take 12 months to develop and make (sometimes quite conspicuous) shelters on the tussocks.
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The survey method used a combination of quadrats and transects. Quadrats measured four by three
metres with the longest edge parallel with the edge of the swamp and were spaced five metres apart
(Figure 13). Every tussock within a quadrat was searched and all shelters were recorded regardless of
the presence of a larva. One team member was charged with describing characteristics of each survey
site. These were entered into a datasheet (Appendix 4) which were then collated, analysed and
synthesised in a population survey report (Butcher, 2017).
Figure 13: Population survey transects and quadrats for the Yellowish Sedge-skipper.
Transects usually ran from the edge of the Gahnia filum sedgeland towards the
centre. A transect always had four quadrats. A quadrat was 4 × 3 m and quadrats were
5 m apart. All tussocks in a quadrat were searched. Most sites had four transects.
It was recorded if the shelter was active (had a larva), details about the location of the shelter on the
leaf (Figure 14) and the tussock (Figure 15), and details about the size and apparent health of the
tussock.
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Figure 14: A stylised Thatching Grass tussock (side view) with a Yellowish Sedge-
skipper shelter on the leaves. The position of the YSS shelter is on the third quarter of
this leaf. These details were recorded during the population survey on southern Yorke
Peninsula in February 2017.
Figure 15: A stylised Thatching Grass tussock (top down view) with a Yellowish Sedge-
skipper shelter on the leaves. The YSS shelter is in the outer ring of this Gahnia filum
tussock. These details were recorded during the population survey on southern Yorke
Peninsula in February 2017.
If the shelter was active, that is to say it had a larva, the following data were recorded:
- Was the larva in pupation? If not;
- What was the approximate instar (growth stage) of the larva (1-5) (Figure 16)?
- Could the gender be determined?
- Was there any evidence of parasites?
- How many larvae were on the tussock?
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4.3.2.3 Overall numbers
The survey found 103 YSS larvae, 53 of which had entered pupation. These larvae were found amongst
334 shelters. Therefore, 30.8 per cent of the shelters found hosted a skipper larva at some stage of the
skipper’s development and the remaining 69.2 per cent were inactive. Of the inactive shelters, most
appeared to be vacated by larvae that had outgrown (next instar) or had pupated. However, several
showed signs of parasites having killed the larvae.
Figure 16: Photos of Hesperilla flavescens larvae and shelters. Top left: a large shelter
made between two or three Gahnia filum leaves. Top right: a small H. flavescens larva,
second or third instar, this will pupate in spring 2017. Bottom left: a large H.
flavescens larva, fifth instar, this will pupate in autumn 2017. Bottom right: an old
shelter showing the exuvia of an emerged pupa.
4.3.3 Preferred habitats
4.3.3.1 Location of shelters on the leaves
There was a trend that most of the shelters found on the February 2017 survey were built along the
centre portion of the leaf (Figure 17). The importance of assessing the location of the shelters with
relation to the outer extremities of the tussock relates to the risk of predation (e.g. mice) or incidental
consumption (e.g. livestock) of larvae on the outer leaves of a tussock. The centre half of the leaf
evidently provides a suitable amount of leaf flexibility and is palatable/soft enough for YSS larvae; this
was seen on both young and mature tussocks (Figure 18).
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This knowledge also helps the reintroduction of the species by demonstrating what is to be expected
for the larvae that will be “released” in the new founder sites. Any difference from these results would
warrant further investigation.
Figure 17: The position along the length of the leaf of Yellowish Sedge-skipper
shelters on Thatching Grass tussocks was recorded for each shelter (February 2017).
Most of the found shelters were built in the middle half of the leaf.
Figure 18: The bent and connected leaves of shelters (circled) were mostly commonly
found in the centre half of a leaf. Left: This young plant hosted six shelters for the
three larvae on the small tussock. Right: The shelter (mid image) is made between
fresh green leaves on this mature Thatching Grass tussock.
0
5
10
15
20
25
30
35
40
45
1/4 2/4 3/4 4/4
Nu
mb
er o
f sh
elte
rs
Shelter on leaf - from begining (1/4) to end (4/4)
Location of YSS shelters on Thatching Grass leaves
Corny Point Swamp -north
Daly Head Swamp
Balaklava Road
Orrie Cowrie Road
Old Saltworks Road
Little MoldarbyWaterhole
Brutus Road - north
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4.3.3.2 Location of shelters on tussocks
Far fewer shelters were found on the centre of tussocks than on the mid to outer leaves of the plant
(Figure 19). Thatching Grass leaves can grow quite close together and tussocks die off in the centre
creating a ring of live leaves (Figure 20). It is expected that both of these factors have influenced what
was found. Firstly, simple leaf accessibility and the flight behaviour of gravid female skippers could
favour the outer leaves; i.e. they may approach the tussock from the side and select one of the outer
leaves that are easily accessible. Secondly, the leaves at the edge of the tussock may be targeted
because they may be noticeably younger and fresher than the central leaves. Younger leaves are
known to be the preference of YSS larvae (New, 1997).
Figure 19: The location of Yellowish Sedge-skipper shelters on Thatching Grass
tussocks during a field survey in February 2017. At most sites, YSS favour the outer
two thirds of the tussock for their shelters (mid and outer ring). All sites except one
(Old Saltworks Road) had many more shelters in both mid-ring and outer-ring areas
of the tussock.
0
5
10
15
20
25
30
35
40
45
Centre Mid-ring Outer-ring
Nu
mb
er o
f sh
elte
rs
Top-down view of tussock
Total YSS shelter locations on Thatching Grass tussocks per site
Corny Point Swamp - north
Daly Head Swamp
Balaklava Road
Orrie Cowrie Road
Old Saltworks Road
Little Moldarby Waterhole
Brutus Road - north
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Figure 20: Some very old Gahnia filum (Thatching Grass) tussocks die-off in the centre
leaving an outer ring of live leaves.
4.3.3.3 Suitable tussocks
Finding good numbers of larvae on the few small and young tussocks was encouraging for
reintroduction efforts. This suggests that the seedlings planted in recent years will be suitable for adult
YSS to lay eggs and for YSS larvae to construct shelters and graze the leaves. This is not to say that
surrounding tussock height is not important. The YSS may prefer a habitat with taller plants for
another part of their life cycle (e.g. mating displays). However, a YSS restoration project in Altona,
Victoria revealed that most shelters were on tussocks less than one metre tall (Relf and New, 2009).
Site preparation strategies can be formed with the knowledge that skippers prefer the fresh green
leaves, combined with an understanding of Thatching Grass’s favourable response to fire. Where
possible, fire could be a useful tool to clear unwanted vegetation and pests, and stimulate new growth
in the tussock.
A study of the Altona, Victoria populations of H. f. flavescens, which are believed to behave similarly to
H. f. flavia, revealed that recently burnt and regenerating sedgelands yielded significantly more eggs
and shelters than older tussocks. This implied that new growth foliage following tussock burning is
attractive and can be exploited within a few months of a fire (Relf and New, 2009).
4.3.3.4 Location of viable sites
The January 2017 site inspection revealed that YSS larvae were present at many sedgelands across
southern Yorke Peninsula. Most of the sites that appear to have populations large enough to sample
were across the northern and eastern reaches of the survey area (Figure 1).
The sites that returned the highest numbers of shelters and larvae in the February survey formed a
corridor of Thatching Grass sedgelands. Looking at topographic maps, the sedgelands appear to
follow natural drainage lines from the Balaklava Road site north towards the Brutus Road sites near
Point Turton (with the Orrie Cowrie Road site in between).
Not all of the sedgelands visited along this drainage line hosted populations of YSS. One site between
Brutus Road and Orrie Cowrie Road had large sedgelands yet no shelters could be found. It was also
observed that site was rather heavily grazed, dry and the tussocks had very few fresh green leaves. The
intensity of grazing at this site is probably the reason shelters were not found and that with exclusion
of grazing then YSS could naturally migrate into this sedgeland following regeneration, forming a new
population.
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5 Target sites
5.1 Sites of Gahnia filum (Thatching Grass) sedgeland in the northern
Adelaide coastal plains
A great deal of work has been done to restore and expand the Thatching Grass sedgelands in the
northern Adelaide coastal plains. The local recovery plan for the Yellowish Sedge-Skipper and
Thatching Grass, which was produced and written for the South Australian Urban Forest Biodiversity
Program (Coleman and Coleman, 2000), was a major impetus for this work. The Recovery Plan
combined with extensive work done by Roger Grund (1997, 2003) has led to the Yellowish Sedge-
skipper and Thatching Grass sedgelands being included as conservation priorities in several
government plans and projects. This in turn has resulted in detailed surveys and several thousand
Thatching Grass seedlings being planted.
5.1.1 Site selection options when creating a potential habitat
When presented with the challenge of providing a habitat for the YSS one can either work to restore
and infill an existing area of Thatching Grass or create a new habitat. Both approaches have merit and
it depends on a case-by-case assessment, working closely with land managers, to determine which
strategy to employ. For example, if all stakeholders are supportive and abiotic factors are suitable, an
excellent YSS habitat might be created in an area overrun with weeds simply because it would be
easier to slash the land back to bare earth and plant it a new; a sort of ‘blank slate’ approach. This
could be more efficient to prepare, given the machinery options, and could result in a better habitat if
one is not limited to having remnant Thatching Grass tussocks. The ‘blank slate’ approach might take
longer to establish a YSS habitat but it gives more flexibility in choosing a suitable site, including
suitable vegetation associations for different broods of the YSS.
This project focussed on sites that have at least some Thatching Grass established and additional
planting has occurred or will occur in the near future.
5.1.2 Vegetation associations that benefit Yellowish Sedge-skippers
Optimal vegetation surrounding a YSS habitat will have a variety of plants that flower at times that
coincide with the nectar needs of the different broods of YSS. The spring brood of adult skippers are
known to feed on the nectar of flowering Eucalyptus spp., Bursaria spinosa (Sweet Bursaria), Melaleuca
halmaturorum (Salt or Swamp Paper-bark), Myoporum insulare (Common Boobialla), Nitraria
billardierei (Nitrebush), and other flowering herbs. The autumn brood tend to rely on the seasonally
flowering M. lanceolata (Dryland Tea-tree) and other flowering herbs (Grund, 2003; Coleman, 2015). It
is important that the sedgeland is not shaded by tall trees during the main daylight hours and that
surrounding trees do not break up the sedgeland. Both sun and warmth are important to the
behaviour of the YSS and excess shade could limit this.
5.1.3 Fire as a management tool
Fire is a powerful management tool, especially for Thatching Grass. Fire of sufficient intensity can
destroy eggs and caterpillars, however, its ability to trigger the new growth preferred by skippers in
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Australian and North America is well documented (COSEWIC, 2003; Relf and New, 2009). If control
burns are used, they must be carefully planned as to compliment the skipper’s life cycles. For example,
burning can benefit the YSS if done on a mosaic early spring burn of no more than half of the site, two
to three weeks after the beginning of the adult flight season, between peak butterfly emergence and
most oviposition. The benefit would be through an increase in Thatching Grass shoots and nectar
plant flowers (Coleman and Coleman, 2000; Dana, 1991; Relf and New, 2009).
5.1.4 Potential YSS habitats in the northern Adelaide coastal plains
The Thatching Grass sedgelands within the project area have been surveyed and most were visited as
part of this feasibility assessment. Each site has its strengths and weaknesses, and is at a different
level of preparedness for YSS translocation (Figure 21). A case-by-case approach is required to
prepare and maintain each site. All of the sites of interest are listed below and shown in Figure 22.
The results of the site surveys are tabulated in Appendix 1.
Site (north to south) Potential Size Suitability
Two Wells golf club Medium High
Windamere Large High
Thompson Creek riparian Medium Medium
Constellation MAC* Medium High
Brooks Road triangle Large High
Symes Road Small Low
Kaurna Park Wetland Large High
Whiting Road Large Low
Little Para Estuary – east Medium Medium
Little Para Estuary – west Medium Medium
Whites Road Wetland Medium Low
Sanctuary Drive Medium Medium
Dry Creek Drainage Medium Low
Greenfields 3 Wetland Large High
Port River Expressway – north Small Low
Port River Expressway – south Small Low
*MAC – model aeroplane club Small: <2500 m2 Medium: 2500 -5000 m2 Large: >5000 m2
Figure 21: Sites in the northern Adelaide coastal plains with Thatching Grass sedges
that have been surveyed for the suitability to reintroduce Hesperilla flavescens
(Yellowish Sedge-skipper).
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Figure 22: Sites with Thatching Grass sedgelands that have been surveyed as potential
sites for the reintroduction of Yellowish Sedge-skipper butterflies.
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5.2 Target Thatching Grass sites as YSS habitats
There are four sites in the northern Adelaide coastal plains that could possibly sustain a population of
Yellowish Sedge-skippers (YSS) with dedicated site preparation. A further three sites that could sustain
a population given greater preparation and time for existing tussocks to establish. Regardless, a range
of preparatory on-ground works is needed prior to any reintroduction. These sites are listed below.
Four key sites that have the greatest immediate potential:
- Brooks Road triangle (City of Playford)
- Constellation Model Aeroplane Club (City of Playford)
- Kaurna Park Wetland (City of Salisbury)
- Salisbury Greenfields 3 Wetland (City of Salisbury)
5.2.1 Brooks Road Triangle
At approximately half a hectare, this is the largest site of mature Thatching Grass in the project area
and as such, it has great potential to be ready to host a population of YSS after support is gained from
the land manager and it is prepared according the recommendations (Figure 23).
Figure 23: Thatching Grass sedgeland and potential Yellowish Sedge-skipper habitat at
the Brooks Road Triangle site. Photo: Chris Butcher, December 2016.
5.2.1.1 Strengths and weaknesses
Strengths
- The largest site of established Thatching Grass in the project area.
- The site is a low and flat sedgeland, which is preferred by the YSS.
- The site is close to Constellation MAC site and other isolated Thatching Grass tussocks.
- There are several nectar sources nearby in the form of mature Melaleuca sp.
- There is no knowledge of soil contamination
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Weaknesses
- Land tenure and minerals lease pose a challenge for this site. Support from the land manager,
relating to the decommissioning of the Dry Creek Saltfield, must be confirmed.
- Many weeds are present, including woody weeds, exotic grasses and herbaceous weeds.
- Site appears to be dry. The tussocks do not have much new growth.
- Rubbish is dumped on the site.
- There is evidence of mice, which could be a predator for YSS larvae.
5.2.1.2 Proposed preparation
A controlled burn would greatly benefit this site. Burning at least half of the Thatching Grass
sedgeland on the site will stimulate new growth, remove some of the weeds, and clear some of the
leaf litter. A low intensity burn should be done between April and August (conditions permitting) but
should be done at least two months before larvae are to be introduced.
Weeds will need to be controlled in line with best practices for each weed. For example, individual
small African Boxthorn plants can be removed or foliar sprayed. Other weeds can be pulled or sprayed
as required. Thatching Grass tussocks should receive a one metre brush-cut followed by a half metre
‘halo’ spray to supress regenerating weeds. The hard rubbish must also be removed from the site, as it
is a health hazard.
Mice at the site need to be removed and maintained. This might be achieved using baits but an
investigation must be done to ensure no off-target damage is done to native species.
The soil hydrology could be changed if the drainage line that runs adjacent the site were modified so
that it spilled onto the site periodically (every few years). This would require an engineered solution
that involved earth works but it could control the weeds, help the Thatching Grass, and consequently
provide a better habitat for the YSS.
5.2.1.3 Proposed maintenance
Weed control every six months for the first 3 years after reintroduction. This will include brush cutting
and ring spraying around tussocks, and the continued monitoring and control of woody weeds.
Pest control must happen at appropriate times to control the pest (e.g. mice). Evidence of grazing and
predation must be done fortnightly after reintroduction for the first six months after reintroduction,
then monthly for the next two and a half years.
Soil condition and plant health should be monitored every three months for three years after YSS
reintroduction.
5.2.2 Constellation Model Aeroplane Club
This site is relatively small (1500 m2) but has great room for expansion (Figure 24). It is less than a
kilometre from the Brooks Road Triangle site and there are several mature Thatching Grass tussocks
between the two sites, which could act as a type of migration corridor.
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Figure 24: Thatching Grass sedgeland and potential Yellowish Sedge-skipper habitat at
the Constellation Model Aeroplane Club site. Photo: Chris Butcher, December 2016.
5.2.2.1 Strengths and weaknesses
Strengths
- The site has a good range of age classes, from mature and established Thatching Grass
tussocks, to tussocks ranging five years old to seedlings planted within two years.
- The site appears to be healthy with a dynamic soil water cycle, which favour Thatching Grass.
There is a shallow drain immediately adjacent the site that appears to flood the soil
periodically, making it boggy.
- There are good nectaring sources for the YSS ranging from mature Melaleuca trees to a wide
range of flowering plants at ground level.
- Tussocks are not overgrown and have good access from the side of the plant.
- There is room for expansion that is being supported by the land manager and local
government officers.
Weaknesses
- The site is still relatively small.
- The rest of this property is regularly mown as part of the club maintenance. It is possible that
the Thatching Grass is only there because of the drainage line. If that drainage line were
removed, there would be no physical barrier for mechanical slashers. This needs to be
discussed and managed with the land manager.
5.2.2.2 Proposed preparation
Little needs to be done to prepare this site. Thatching Grass tussocks will benefit from brush-cutting
one metre around them. ‘Halo’ spraying with herbicide may be possible depending on the vegetation
type. It would be highly desirable to continue infilling and expanding this site. A site inspection should
be done six months prior to reintroduction to ensure there are no issues with weeds or pests (e.g.
mice).
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5.2.2.3 Proposed maintenance
Weed control every six months for the first 3 years. This will include brush cutting and ring spraying
around tussocks, and the continued monitoring and control of woody weeds.
Pest control must happen at appropriate times to control the pest (e.g. mice). Evidence of grazing and
predation must be done fortnightly after reintroduction for the first six months after reintroduction,
then monthly for the next two and a half years.
Soil condition and plant health should be monitored every three months for three years after YSS
reintroduction.
5.2.3 Kaurna Park Wetland
This 1370 m2 site is located in the northwestern section of a large nature reserve, which is similar to a
botanic garden (Figure 25). The wetland has a carpark and several well-maintained walking tracks
throughout. Adding YSS to this site will get high public exposure.
Figure 25: Thatching Grass sedgeland and potential Yellowish Sedge-skipper habitat at
the Kaurna Park Wetland site. Photo: Chris Butcher, December 2016.
5.2.3.1 Strengths and weaknesses
Strengths
- There are many Thatching Grass tussocks forming a habitat that could support a small
population of YSS.
- The site is in a park that is well maintained and protected. Risk of damage or weed infestation
is low.
- There is room for expansion of the sedgeland in the adjacent grass, which is in full sun.
- There are many nectar source nearby and high native biodiversity.
- There is a good flooding/drying cycle of the soil.
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Weaknesses
- Many of the tussocks are periodically shaded throughout the day.
- Plant density and sedgeland size need to be increased.
5.2.3.2 Proposed preparation
The sedgeland could be expanded on to the grass immediately to the west of the existing tussocks
(Appendix 1). This site would be greatly improved if several hundred Thatching Grass seedlings were
planted in the open space adjacent the trees.
An information sign should be posted at each entry to the park and at the Thatching Grass sedgeland
to garner interest in the species and attract park visitation.
There are not many weeds however, they should be checked and controlled accordingly starting six
months prior to reintroduction. Thatching Grass tussocks should receive a one metre brush-cut
followed by a half metre ‘halo’ spray to supress regenerating weeds.
5.2.3.3 Proposed maintenance
Site visitation should be monitored to gauge if the YSS has become a feature of interest in the park.
Weed control every six months for the first 3 years. This will include brush cutting and ring spraying
around tussocks, and the continued monitoring and control of woody weeds.
Pest control must happen at appropriate times to control the pest (e.g. mice). Evidence of grazing and
predation must be done fortnightly after reintroduction for the first six months after reintroduction,
then monthly for the next two and a half years.
Soil condition and plant health should be monitored every three months for three years after YSS
reintroduction.
5.2.4 Salisbury Greenfields 3 Wetland
This 14,700 m2 site runs adjacent the Salisbury Highway and is set in an artificial wetland comprised of
a series of small islets, established trees, and Thatching Grass tussocks (Figure 26). With NRM and
council support, it has been prepared and planted with over three thousand Thatching Grass seedlings
over the past three years explicitly to suit the YSS. It has since been monitored and maintained.
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Figure 26: Thatching Grass sedgeland and potential Yellowish Sedge-skipper habitat at
the Salisbury Greenfields 3 Wetland. Photo: Chris Butcher, December 2016.
5.2.4.1 Strengths and weaknesses
Strengths
- There are many Thatching Grass tussocks, young and established, that could support a
population of YSS.
- There is room for expansion of the sedgeland in the adjacent grass.
- There are many nectar source nearby and high native biodiversity.
- There is a good flooding/drying cycle of the soil.
- The site has been maintained for the last three years and weeds are at a minimum.
Weaknesses
- The site is near a busy highway that is noisy and can spread dust, pollution, and potentially
disease.
- Weed and rubbish dumping.
5.2.4.2 Proposed preparation
Little needs to be done to prepare this site. The guards will need to be removed from the Thatching
Grass tussocks and brush-cutting one metre around them. ‘Halo’ spraying with herbicide may be
possible depending on the vegetation type. A site inspection should be done six months prior to
reintroduction to ensure there are no issues with weeds or pests (e.g. mice).
5.2.4.3 Proposed maintenance
Weed control every six months for the first 3 years. This will include brush cutting and ring spraying
around tussocks, and the continued monitoring and control of woody weeds.
Pest control must happen at appropriate times to control the pest (e.g. mice). Evidence of grazing and
predation must be done fortnightly after reintroduction for the first six months after reintroduction,
then monthly for the next two and a half years.
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Soil condition and plant health should be monitored every three months for three years after YSS
reintroduction.
5.3 High and medium potential habitats of Thatching Grass sedgelands
Other sites, listed in Figure 21, showed excellent promise as being potential habitats for the YSS.
After the four key target sites listed above, these three sites that showed excellent promise in the
near future with some good management:
- Two Wells Golf Club (City of Adelaide Plains)
- Thompson Creek riparian (City of Playford)
- Windamere site (City of Playford)
5.3.1 Two Wells Golf Club site
This is currently a 2600 m2 patch of Thatching Grass is set near the northern boundary of Two Wells
Golf Club (Figure 27). There are several good points about this site. One to two hundred Thatching
Grass tussocks are in a relatively open and flat sedgeland setting. The site is set within the golf course,
which is maintained and protected from major human impact (e.g. off-road vehicles). A discussion
with the course president revealed that if any golf balls enter that area, then the player must remove
the ball and play from the fairway i.e. no golf swings amongst the tussocks. There is also high native
biodiversity, many mature native trees and nectaring sources for the YSS.
Some factors of the site that are either limiting or negative will take some time and good
management to resolve. While there is room for expansion of the sedgeland, it can effectively double
in size, that room is limited between the two fairways on either side. There was also evidence of heavy
grazing on the Thatching Grass done by rabbits. Many of the fresh outer leaves of the tussocks had
been grazed. Considering that the YSS shelters are on the outer leaves and the larvae prefer the fresh
leaves, the threat of rabbit grazing must be eliminated before YSS are introduced to this site. This
could potentially be done with a rabbit-proof fence around the sedgeland; however, native animals
are known to use that same habitat so an impact assessment must be done before setting up physical
barriers.
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Figure 27: Thatching Grass sedgeland (centre and left) and potential Yellowish Sedge-
skipper habitat at the Two Wells Golf Club site. Photo: Chris Butcher, March 2017.
This site could potentially be ready for YSS if it were not for the heavy grazing impact. The site could
potentially host a population of YSS given the following conditions:
- Options for a controlled burn of the tussocks are explored and assessed.
- Rabbits are excluded from the area.
- Other pests such as mice are checked for and controlled.
- The site is expanded to fill the available space.
- Seasonal grasses and weeds are controlled.
- Thatching Grass tussocks receive a one metre radius brush-cut and half metre halo spray for
regenerating weeds.
5.3.2 Thompson Creek riparian
This site is a restored and revegetate site (2002) between a low-traffic roadside and Thompson Creek
(Figure 28). The site is 400 metres long but narrow and on a slope with an intermittent band of around
fifty established Thatching Grass tussocks along the length of it.
On the positive aspects of the site, there are many established and fresh-looking Thatching Grass
tussocks. The site has many mature Melaleuca trees that provide shelter and a nectaring source for the
YSS. There also appears to be few weeds at the site.
Unfortunately, the site is not the preferred open and flat layout that is seen in some of the preferred
sites. This makes the site less suitable for the skipper for a large population. The tussocks are also set
amongst native samphire and chenopod vegetation, which makes expansion of the sedgeland
difficult, as some of the native vegetation would need to be cleared.
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Figure 28: Thatching Grass sedgeland and potential Yellowish Sedge-skipper habitat at
the Thompson Creek Riparian site. Photo: Chris Butcher, December 2016.
The site could potentially host a population of YSS given the following conditions:
- Options for a controlled burn of the tussocks are explored and assessed.
- Pests such as mice are checked for and controlled six months prior to reintroduction.
- The site is expanded and infilled where possible, considering the limitations presented by
thick native vegetation.
- Seasonal grasses and weeds are controlled.
- Thatching Grass tussocks receive a one metre radius brush-cut where possible.
5.3.3 Windamere site
The Windamere site is located on private land near the southern boundary of Buckland Park reserve. It
is part of a ten hectare artificial wetland constructed in 2000 and planted with several hundred
Thatching Grass seedlings (Figure 29).
This site has excellent potential for YSS reintroduction. This large site has the opportunity to be
prepared and maintained by the land manager. It has many mature and established Thatching Grass
tussocks that appeared healthy with some diverse age classes. The site is well protected by
surrounding mature trees that can also act as a nectaring source. There is room in the inner section of
the wetland to be planted with several thousand more Thatching Grass seedlings. The soil appears to
be cracking soil that is periodically inundated or at least becomes boggy once every one to two years.
Issues with the site are that the Thatching Grass tussocks are planted in a ring, sometimes a single line,
around the wetland, which is not preferred by the YSS. There also is strong competition for space with
grasses and sedges, many of which currently crowd the sides of the Thatching Grass tussocks.
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Figure 29: Thatching Grass sedgeland and potential Yellowish Sedge-skipper habitat at
the Windamere site. Photo: Chris Butcher, December 2016.
The site could potentially host a population of YSS given the following conditions:
- Options for a controlled burn of the tussocks are explored and assessed.
- Grasses, sedges and weeds are controlled. This includes the Bathurst Burr and Spiny Rush that
were seen on site in February 2017.
- Pests such as mice are checked for and controlled six months prior to reintroduction.
- The site is expanded and infilled where possible, considering the limitations presented by
thick native vegetation.
- Thatching Grass tussocks receive a one metre radius brush-cut and half metre halo spray to
control regenerating weeds.
5.4 Medium and low potential habitats of Thatching Grass sedgelands
The remaining sites that were listed at the start of this section show potential but getting each site to
a point where YSS can be introduced will take more time and more work than the sites already
described. A description of the sites can be found below (Figure 30); some of the sites are also
described in Progressing the Local Recovery Plan (Coleman, 2015).
Site Description
Symes Road
(corner of Casson)
Two areas north and south of the road. These sites have been infill planted with
Thatching Grass in recent years with mixed success. The sites are small with
potential for expansion if surrounding land managers (especially to the south) are
supportive. This site adds to the connectivity of the nearby Brooks Road site,
Constellation MAC site, and other scattered Thatching Grass clumps.
Whiting Street Reserve Individual Thatching Grass seedlings were planted amongst other native species in
four patches within this The only potential for this site as a YSS habitat is if a
dedicated planting of Thatching Grass is done. There is a shallow swale on the
northern edge of the reserve that may suit Thatching Grass. Planting several
hundred Thatching Grass between two of the patch could create a viable YSS
habitat but this would take at least three years to establish.
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Little Para Estuary – east These three sites are close to each other and have been planted with Thatching
Grass seedlings in recent years. The Little Para Estuary – east site is set in an open
wetland close to nectaring sources. This site has excellent potential for expansion
and could support a small YSS population once the tussocks are better established.
The Little Para Estuary – west site is smaller at this stage and further from
nectaring sources than the eastern site; however is good opportunity for expansion
and connectivity with the other two sites. The Whites Road Wetland was recently
planted but the seedlings were flooded during recent periods of high rainfall.
Replanting of this site is recommended after closer consultation with what
conditions suit the YSS.
Little Para Estuary – west
Whites Road Wetland
Sanctuary Drive (Mawson
Lakes)
This is a suburban wetland that backs on to the Dry Creek Drainage line. Most of
the Thatching Grass here grows in a ribbon at the western end of this site. This site
is well maintained and has excellent potential for expansion and exposure to
nature lovers. It could host a medium population of YSS once more tussocks are
planted and established.
Dry Creek Drainage This site is close to the Sanctuary Drive site but has a more natural, less manicured
setting. It has twice been planted with Thatching Grass but both plantings have
failed due to competition with weeds. If this site has good potential to host a YSS
population if it is planted again with two to three hundred seedlings and
maintained.
Port River Expressway swale
– north
There are over 200 established Thatching Grass tussocks at this site but they are
scattered and very close to the road. Mature trees and shrubs provide a nectaring
source but they also shade many of the tussocks. This site will need extensive infill
planting and preferably some level of screening or buffering from the busy
expressway that is only metres from the site.
Port River Expressway swale
– south
There are over 200 established Thatching Grass tussocks at this site but they are
scattered. This site offers better protection than the northern swale with a drop of
three to four metres down a bank and about 15 metres from the road. Mature
trees and shrubs provide a nectaring source but they also shade many of the
tussocks. This site may provide a habitat for YSS with infill planting and weed
maintenance but there are better options presented above.
Figure 30: Sites of Thatching Grass within the northern Adelaide coastal plains with a
brief description relating to suitability of Yellowish Sedge-skipper reintroduction.
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6 Reintroduction strategy
The life cycle of the Yellowish Sedge-skipper is that of two weeks as an egg, twelve months as a larva
and approximately six weeks as a mature butterfly. When considering the optimal life stage for
translocation, mature skippers are illusive, fast and would be difficult to collect. The report,
“Progressing the Local Recovery Plan” (Coleman, 2015) proposed harvesting eggs from Thatching
Grass on southern Yorke Peninsula and bringing them to the Thatching Grass tussocks in the project
area. This would be a feasible method of translocating the species however, YSS eggs are quite small
and difficult to locate on sedges, and the gestation period of the eggs allows only a short window per
brood to locate and transport the eggs. Australian and international studies reported the practice of
using wild-caught larvae for reintroduction and using a combination of releasing larvae into habitats
and rearing to maturity (Nicholls and Pullin, 2000, Relf and New, 2009). For the YSS, it is recommended
that the best life stage to translocate the YSS is during its larval stage (Alex Stolarski pers.com. 2017).
6.1 What to collect and from where
The collection of eggs may still be considered as an option if seasonal timing is better suited for this
method; however, there are justifiable reasons for collecting larvae instead of eggs. The benefits of
translocating YSS in its larval phase are below:
- Collecting larvae will be easier than collecting eggs. The shelters of the larval skippers are
easier to find than the eggs and larvae are in approximately one third of the shelters.
- Timing is less critical than with eggs. The larvae stage lasts 12 months (not two weeks), which
allows for some flexibility for harvest times when managing the project.
- Larvae can rebuild shelters in new tussocks without adversely affecting them.
The sites from which the larvae are collected should vary but focus on sites that have been surveyed.
Collecting from a variety of sites will increase the amount of genetic diversity in a population, which
will increase its resilience against stresses such as disease. Furthermore collecting from different sites
will reduce the impact on populations from which collect are collected.
The population surveys done for this project was not able to establish a population estimate for the
region. It was possible to determine which sites gave the best indications of having a population of
YSS from which larvae could be collected. These sites are Balaklava Road site, Brutus Road site (north),
Orrie Cowrie Road site, and the Daly Dead Swamp. These sites should be surveyed more thoroughly
before collecting larvae from them. Eight more transects should be surveyed, effectively trebling the
area of sedgeland that has been surveyed (for most sites).
A conservative estimate of how many larvae to collect is one out of every five larvae found. With our
current understanding of the populations and the breeding habits of the YSS, this level of sampling
should not significantly affect the population (Alex Stolarski pers.com. 2017).
6.2 When and how to collect
Being selective with which larvae to collect is important. Ideally it is preferred if the YSS emerge from
pupation at the same time so that they can interact and propagate the next generation. Therefore,
larvae in their third or fourth instar would be ideal. This means collecting in December for the autumn
brood and collecting in June for the spring brood.
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The best way to collect the larvae is listed below:
- Prepare an empty specimen jar or similar sealed container.
- Locate a shelter containing a larva.
- Cut the shelter from the plant about five centimetres from the shelter.
- Place some fresh leaves from the same tussock into the container.
- Open the shelter and place the shelter in the container (shelters dry and contract once cut
from the plant rendering them unsuitable).
- Inspect the larva for any evidence of parasites or abnormalities. If it appears to be healthy and
clear from parasites, place it into the container along with its opened shelter.
- Seal the container and store out of direct sunlight.
- Up to five larvae can be stored in a container.
6.3 How to move them
The containers should be kept out of direct sunlight and in a cool and dry place; high humidity can
badly affect larval health. Larvae can survive in the specimen containers for up to two days in the
conditions they were placed in (i.e. as in section 6.2). Any longer increases the risk of humidity creating
issues for the larvae and the leaves will no longer be fresh.
They can be transported in a climate-controlled car. As long as it is comfortable for people and not
too humid, then the larvae should survive.
Larvae are active at night. They should therefore be introduced to their new habitat in the evening.
This will give larvae the opportunity to acclimatise to their surroundings, feed, and build a new shelter.
It is unclear how water on the leaves affects the larvae’s ability to make shelters so it is better if it is
not raining and the leaves are not wet when they are introduced. A larva can be gently placed near the
centre of the tussock in a place where it can move to its desired leaf to feed or build a shelter. No
more than three larvae should be placed on a tussock because this is the maximum number found on
a tussock on southern Yorke Peninsula; competition between larvae could be a factor. The tussock
must appear healthy, have fresh growth, not be shaded by trees or over-crowded by weeds, and will
ideally have good access from the sides.
6.4 Where to move them
The four key target sites described in section 5.2 have the best chance to host and sustain a
population of YSS in the shortest amount of time. It is proposed that each of these sites should be
used as pilot habitats for the reintroduction of the YSS into the northern Adelaide coastal plains. These
sites are:
- Brooks Road triangle (City of Playford)
- Constellation Model Aeroplane Club (City of Playford)
- Kaurna Park Wetland (City of Salisbury)
- Salisbury Greenfields 3 Wetland (City of Salisbury)
Each site should get an initial 50 larvae from one brood that are approximately two months from
pupation (third or fourth instar). They will be placed on healthy Thatching Grass tussocks with new
Yellowish Sedge-skipper Reintroduction Feasibility Project – Final Report
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growth and each will have a GPS waypoint and visual identification (e.g. flagging tape or pegs). There
will need to be frequent and regular monitoring (i.e. weekly) until pupation to watch for negative
impacts of predation, grazing, disease or positive signs such as the construction of new shelters or
pupation. General site observations will also be recorded. After pupation, fortnightly monitoring
should be maintained until the introduction of the other brood six months later. Each step will be
repeated for the other brood.
A contingency translocation should be planned to account for losses due to mortality during
translocation or settling (e.g. parasites). This should be assessed three months after each translocation
and implemented only if the risks that have caused triggered the contingency have been mitigated.
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7 Recommendations
Results from this feasibility assessment suggest that it will be possible to reintroduce both broods of
founder populations of Hesperilla flavescens (Yellowish Sedge-skipper) into the project area of the
northern Adelaide coastal plains given that sites are suitably prepared. If the aim is to collect larvae
from suggested sites on southern Yorke Peninsula in December (autumn brood) then the following
work must be done in the six months leading to this:
- Current detailed population surveys at a minimum of four of the best donor sites (section 4).
- Preparation of the key target sites, including fire management, as described (section 5).
- Promotional campaign including more public talks, school visits, field trips, and meeting with
volunteer groups, land managers and other stakeholders.
- The continued coordination of efforts with local and state government agencies with regard
to improving and expanding the Thatching Grass sedgelands under their charge.
Once the YSS is reintroduced into the northern Adelaide coastal plains the YSS, plant health and site
condition will need to be monitored using expert advice from butterfly specialists and the
recommended steps (section 6). Sites will also need to be regularly maintained for at least three years
(e.g. pest and weed control). Site maintenance may depend partly on volunteer effort; therefore, it is
vitally important for the project to retain high exposure and consequently high interest within the
local community. Results must be analysed made available to stakeholders, including funding bodies,
for their information and promotion.
Successive generations of the autumn brood of YSS will be visible fourteen to eighteen months after
the initial release of larvae at key target sites; larvae from the spring brood will be found six months
later. Monitoring and reporting these events is key to gauging the success of the reintroduction. The
results will allow calculations for reintroduction to other sites in the northern Adelaide coastal plains
or bolstering populations at current sites.
There is a need to continue to pursue the administrative protection of the Thatching Grass sedgelands
on southern Yorke Peninsula and within the project area. Currently, agencies and land managers are
largely supportive of what the project is aiming to achieve. This must be maintained and strengthened
where possible through a stakeholder engagement/communication strategy.
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8 References
ALA - The Atlas of Living Australia (Record last updated 18/03/2015). Preserved Specimen of Hesperilla
flavescens (Yellow Sedge-skipper). Identified by Fisher, R. H. 05/09/1985. Retrieved November 17, 2016,
from http://www.ala.org.au/
Braby, M (2000) Butterflies of Australia: Their Identification, Biology and Distribution. CSIRO Publishing.
Britton, D (2015) What are the differences between butterflies and moths? - Australian Museum. [online]
Australianmuseum.net.au. Available at: http://australianmuseum.net.au/what-are-the-differences-
between-butterflies-and-moths [Accessed 3 Nov. 2016].
Butcher, C (2016) Yellowish Sedge-skipper Butterfly Reindtroduction Feasibility Project – Literature
review. Prepared for the Nature Conservation Society of South Australia for the Adelaide and Mt Lofty
Natural Resources Management Board (Samphire Coast Icon Project).
Caton, B, Fotheringham, D, Krahnert, E, Pearson, J, Royal, M and Sandercock, R (2009) Metropolitan
Adelaide and Northern Coastal Action Plan. Prepared for Adelaide & Mount Lofty Ranges Natural
Resource Management Board and Department for Environment and Heritage, Adelaide.
City of Salisbury (2010) Biodiversity corridors plan, [online] Available at:
http://www.salisbury.sa.gov.au/Live/Environment_and_Sustainability/Sustainability_and_Climate_Chang
e/Biodiversity_and_Open_Space
Coleman, P (2015) Progressing the Local Recovery Plan: Yellowish sedge-skipper butterfly & Thatching
Grass. Prepared for: Natural Resources Adelaide & Mt Lofty Ranges and Australian Government,
Samphire Coast Icon Project Biodiversity Fund.
Coleman, P & Coleman, F (2000) Local recovery plan for the Yellowish Sedge-skipper and Thatching
Grass. Saint Kilda, South Australia: Delta Environmental Consulting.
Common, I & Waterhouse, D (1972) Butterflies of Australia. Sydney: Angus and Robertson.
COSEWIC (2003) COSEWIC assessment and status report on the Dakota skipper, Hesperia dacotae in
Canada. Committee on the status of endangered wildlife in Canada, Ottawa.
Dana, R (1991) Conservation management of the prairie skippers Hesperia dacotae and Hesperia ottoe:
basic biology and threat of mortality during prescribed burning in spring. Minnesota agricultural
experiment station bulletin 594-1991. University of Minnesota, St Paul.
DEWNR (Department of Environment, Water and Natural Resources) (2014) Regional Species
Conservation Assessment Project. [online] Available at: http://www.environment.sa.gov.au/managing-
natural-resources/plants-and-
animals/Threatened_species_ecological_communities/Regional_significant_projects/Regional_Species_
Conservation_Assessment_Project [Accessed 1 Nov. 2016].
Gillam, S and Urban, R (2014) Regional Species Conservation Assessment Project, Phase 1 Report:
Regional Species Status Assessments, Adelaide and Mount Lofty Ranges NRM Region. Department of
Environment, Water and Natural Resources, South Australia.
Grund, R (1997) Interim Recovery Plan. Recovery of Hesperilla flavescens flavia (Lepidoptera:
Hesperiidae), the yellowish skipper. Report to National Heritage Trust, Canberra.
Yellowish Sedge-skipper Reintroduction Feasibility Project – Final Report
48
Grund, R (2003) The yellow sedge-skipper on Yorke Peninsula. Prepared for Butterfly Conservation
South Australia Inc.
Kraehenbuehl, D (1993) A natural history of the genus Gahnia, Family Cyperaceae, South Australian
Naturalist 67(3,4), 44-62.
Kraehenbuehl, D (1996) Pre-European vegetation of Adelaide – A survey from the Gawler River to
Hallett Cove, Nature Conservation Society of South Australia, Adelaide.
New, T (2011) Butterfly conservation in South-Eastern Australia. 1st ed. New York: Springer, 55-65.
New, T and Sands, D (2002) Conservation Concerns for Butterflies in Urban Areas of Australia. Journal
of Insect Conservation, 6(4), 207-215
New, T and Sands, D (2004) Management of threatened insect species in Australia, with particular
reference to butterflies. Australian Journal of Entomology, 43(3), 258-270.
Nicholls, C, Pullin, A (2000) A comparison of larval survivorship in wild and introduced populations of
the large copper butterfly, Biological Conservation, 93(3), 349-358.
Ralph, M (1994) Germination of local native plant seed. 1st ed. Fitzroy, Victoria: Murray Ralph.
Relf, M and New, T (2009) Conservation needs of the Altona Skipper butterfly, Hesperilla flavescens
flavescens Waterhouse (Lepidoptera: Hesperiidae), near Melbourne, Victoria. Journal of Insect
Conservation, 13(2), 143-149.
Rural Industries Research and Development Corporation (2011) Revegetation by Design - Promoting
the ‘on-farm’ use of native vegetation as agents of ‘natural pest control’. RIRDC Publication No. 11/002.
Canberra: Union Offset Printing.
Savage, E (2002) Options and techniques for managing Chaffy Saw-sedge (Gahnia filum) as habitat for
the Altona Skipper butterfly (Hesperilla flavescens flavescens). Conservation and environmental
management, occasional paper series. Parks Victoria, Melbourne.
Scott, J (1984) The phylogeny of butterflies (Papilionoidea and Hesperioidea). Journal of research on
the Lepidoptera, 23(4), 241-281.
Wilson, K (1993) Gahnia filum (Labill.) F.Muell. PlantNET (The NSW Plant Information Network System).
Royal Botanic Gardens and Domain Trust, Sydney. Retrieved October 20, 2016, from
http://plantnet.rbgsyd.nsw.gov.au/
Wood, G and Coleman, P (2016) Gahnia filum: Insect use of Thatching Grass. Prepared for: Adelaide
and Mt Lofty Ranges Natural Resource Management Board.
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9 Appendices
9.1 Appendix 1
Thatching Grass in northern Adelaide coastal plains
9.1.1 Brooks Road triangle
Site name Brooks Road Triangle
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 274191 North: 6156520 Zone: 54
Size of habitat Approximately half a hectare with over 3500 tussocks.
Site report and notes The site is dry with many old plants with annual grass crowding the sides. Thatching
Grass form the open and flat sedgeland preferred by YSS, however the crowding of all
plants here is an issue. There are many native plant species amongst the Thatching Grass
along with a rich animal biodiversity (mostly insects and spiders). Pests include woody
weeds and annual grasses. The presence of mice was noted. Hard rubbish (metal and
glass) has been dumped on the site near the western boundary.
Recommendations - Controlled low intensity burn.
- Mice are removed from the site and maintained.
- Weeds are controlled (woody and annual). - Surrounding native grasses (if any) are slashed or brush-cut. - Halo or ring spray weeds around tussocks within 2 weeks of brush-cut. - Change in hydrology is preferred (divert adjacent drain).
Earth bank on the north-western edge of the sedgeland
(left).
Evidence of mice at the site.
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Hard rubbish dumped on site. Woody weeds amongst the dense sedgeland.
Thatching Grass tussocks are overcrowded at the sides.
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Site access map for Brooks Road Triangle, Constellation Model Aeroplane Club and
Symes Road sites
Approximate extent of the Brooks Road Triangle site
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9.1.2 Constellation Model Aeroplane Club site
Site name Constellation Model Aeroplane Club site
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 274733 North: 6156855 Zone: 54
Size of habitat The site is currently spread over 1500 square metres with several hundred Thatching Grass
of mixed aged class.
Site report and
notes
This site has been planted in 2000/2001/2002 and 2016. It is less than a kilometre from
the Brooks Road Triangle site and there are several mature Thatching Grass tussocks
between the two sites. Healthy plants with a dynamic soil water cycle due to a shallow
drain immediately adjacent the site. There are good nectaring sources for the YSS.
(Melaleuca trees to a wide range of flowering plants). Tussocks are not overgrown and
have good access from the side of the plant.
Recommendations - Brush cut around tussocks and ring spray tussocks if necessary.
- Monitor for pest and weeds in the months leading to reintroduction.
Mixed age classes of Thatching Grass. Left: established;
Middle: seedling; Background: mature
Good native plant diversity
Open drain adjacent the site Good access to the side of tussocks
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Site access map for Brooks Road Triangle, Constellation Model Aeroplane Club and
Symes Road sites
Approximate extent of the Constellation Model Aeroplane Club site
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9.1.3 Kaurna Park Wetland site
Site name Kaurna Park Wetland site
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 280758 North: 6153333 Zone: 54
Size of habitat This site is approximately 1370 square metres with two to three hundred Thatching
Grass tussocks.
Site report and notes This could potentially sustain a population within one year. The site is in a park that
is well maintained and protected. Risk of damage or weed infestation is low. There
is room for expansion of the sedgeland in the adjacent grass, which is in full sun,
open and flat. Many nectar source nearby and high native biodiversity. Good
flooding/drying cycle of the soil. Tussocks are periodically shaded throughout the
day. Plant density and sedgeland size need to be increased.
Recommendations - Expand sedgeland into grass immediately west of the current plants
(satellite image below).
- Information signs at park entry and at the sedgeland.
- Check and control weeds accordingly
- Brush-cut followed by a half metre ‘halo’ spray
Scattered but healthy tussocks Flooding could occur annually
Tussocks are periodically shaded Open grass that could be planted with Thatching
Grass
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Site access map for Kaurna Park Wetland site
Approximate extent of Kaurna Park Wetland site
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9.1.4 Salisbury Greenfields Stage 3 wetlands site
Site name Salisbury Greenfields Stage 3 wetlands site
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 279378 North: 6143714 Zone: 54
Size of habitat This site is currently spread over approximately one hectare and is planted with over
3000 Thatching Grass tube-stock (with several mature tussocks).
Site report and
notes
There are many Thatching Grass tussocks, young and established, that could support a
population of YSS. The site allows for plenty of expansion in the adjacent grass. Good
nectar sources are nearby and high native biodiversity. Good flooding/drying cycle of
the soil. The site is also near a busy highway that is noisy and can spread dust, pollution
and potentially disease.
Recommendations - Removal of guards
- Continue pest and weed management currently in action on the site.
Guarded seedlings (1-2 yr) and mature tussocks. Healthy seedlings amongst emerging samphire
vegetation.
Islets are set amongst narrow ephemeral waterways Expansion can occur in all directions from the current
planting.
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Site access map for Salisbury Greenfields Stage 3 wetlands site
Approximate extent of the Salisbury Greenfields Stage 3 wetlands site
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9.1.5 Two Wells Golf Course site
Site name Two Wells Golf Course site
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 277532 North: 6170683 Zone: 54
Size of habitat This is currently a 2600 square metre patch of Thatching Grass.
Site report and
notes
There are one to two hundred Thatching Grass tussocks, relatively open and flat
sedgeland setting. Set within the golf course that is maintained and protected from
major human impact. High native biodiversity, many mature native trees, and nectaring
sources for the YSS.
Room for expansion of the sedgeland, effectively double, but room is limited between
the two fairways on either side. Evidence of heavy grazing done by rabbits.
Recommendations - Controlled burn of the tussocks options explored and assessed.
- Rabbits are excluded from the area.
- Other pests such as mice are checked for and controlled.
- The site is expanded to fill the available space.
- Seasonal grasses and weeds are controlled.
- Thatching Grass tussocks receive a one metre radius brush-cut and half metre
halo spray for regenerating weeds.
Sedgeland set amongst native trees. Heavy rabbit traffic around base of tussocks
Some tussocks grazed to near death. Expansion is possible but limited.
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Site access map for the Two Wells Golf Club site
Approximate extent of the Two Wells Golf Club site
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9.1.6 Thompson Creek riparian site
Site name Thompson Creek riparian site
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 272354 North: 6159128 Zone: 54
Size of habitat The site is approximately 400 long and narrow, smaller than a hectare.
Site report and
notes
This long and narrow site has a ribbon of Thatching Grass on the southern side of the
creek. Most tussocks are on the lower point of the slope down from the roadway. The
understorey is mixed chenopod saltmarsh with clumps of mature Melaleuca
halmaturorum and M. lanceolata.
Recommendations - Expanded and infilled where possible.
- Seasonal grasses and weeds are controlled.
- Thatching Grass tussocks receive a one metre radius brush-cut where possible.
The creek, vegetated bank, ribbon of tussocks and
mature trees.
The vegetated bank opens at the northern end with
scattered tussocks.
The southern end with guarded roadside vegetation. Looking downstream (from north) shows potential area
for expansion.
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Site access map for Thompson Creek riparian site
Approximate extent of Thompson Creek riparian site
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9.1.7 Windamere site (Buckland Park)
Site name Windamere site
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates East: 270427 North: 6161189 Zone: 54
Size of habitat This site is almost ten hectares but only the outer ring is vegetated with a ribbon of
Thatching Grass. There are several hundred established tussocks.
Site report and
notes
Located on private land near the southern boundary of Buckland Park reserve. Excellent
potential for YSS reintroduction. Many mature and established Thatching Grass
tussocks that appeared healthy with some diverse age classes. Well protected by
surrounding mature trees that can also act as a nectaring source. There is room in the
inner section of the wetland to be planted with several thousand more. Cracking soil
that is periodically inundated or at least becomes boggy once every one to two years.
Recommendations - Controlled burn options explored.
- Grasses, sedges and weeds are controlled (including Bathurst Burr and Spiny
Rush).
- Checked for pest species.
- Expanded and infill where possible
- Brush-cut and half metre halo spray to control regenerating weeds.
Scattered tussocks and room for expansion. Mature tussocks and nectaring sources.
Crack soil shows dynamic water cycle. A thin ribbon of existing plants.
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Site access map for the Windamere site
Approximate extent of the Windamere site
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9.2 Appendix 2
Thatching Grass and Yellowish Sedge-skippers in southern Yorke Peninsula
9.2.1 Corny Point Swamp – north
Site name Corny Point Swamp - north
Land Manager Mark Filmer Landholder Contact 0427 618 152
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -34°55’48.5” Longitude: 137°2’51.6” E: 687024.8 N: 6132789 Zone: 53
Site access The site is near the north-western tip of southern Yorke Peninsula. It is easy to access from
Marion Bay Road, 2.5 kilometres south of its intersection with Corny Point Road. Access to the
site is down a dirt track on the eastern side of Marion Bay Road. A single shed can be seen on
the track 300 metres from the turn off.
Once the track passes through the gate 550 metres from the road, the sedgelands can be seen
in patches on either side of the track. The track continues through a patch of Melaleuca and
samphire and opens to more Thatching grass on the other side.
Land use This area of land is large and is divided by several fences. There was evidence of grazing in
transects 1 and 2.
Transect selection Four transects were surveyed at this site. Due to the patchiness of the Thatching Grass (10-20%
coverage), to avoid quadrats landing in bare patches, two transects were laid in sedgeland on
each side of the swamp patch. Never-the-less, this section of the Corny Point Swamp was quite
patchy.
Quadrats surveyed 16 Mean larvae per quadrat (12 m2) 0.44 Total shelters 29
Area surveyed (m2) 192 Potential larvae in transects 15.75 Total larvae 7
Size of habitat The swamp is very large but it is unclear how much Thatching Grass is present. Further
exploration is needed.
Site report and
notes
This site was assessed on each side of the swamp. Site A is the western site, Site B is the eastern.
Site A
Composition: Gahnia filum open sedgeland. Average height of 1.3 metres and average cover
of 10 - 20%. Understorey of dense low, introduced grasses: *Hordeum sp., *Avena barbata. Area
fringed by Melaleuca lanceolata open woodland in poor to moderate condition.
Soil: Grey silty clay with significant calcrete outcrop and strew (up to 15%). Litter low (~5%)
Bare ground (10 %+), Microphytic crust (~25%).
Grazing: Gahnia - light and heavy grazing around bases common but rarely severe. Likely by
sheep. Sheep droppings very frequent. Few if any kangaroo scats.
Site B
Composition: Gahnia filum open sedgeland. Average height: 1.2 metres. Average cover: 10%
(range between 5%-20%). Understorey: dense to mid-dense low, introduced grasses: *Hordeum
sp., *Avena barbata, over dense introduced herbs: *Trifolium spp., *Medicago spp.
Soil: Grey silty clay with significant calcrete outcrop and strew (15%). Litter low (5%), Bare
ground (15%), and Microphytic crust (25%)
Grazing: Gahnia - light and heavy grazing around bases common, severe rarely. Likely by
sheep.
Notes: This was the first site that was surveyed and the survey team were trained at this site.
With this in mind, it is possible that some shelters were not noticed due to the lack of
experience in the team.
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This northern site was patchy and we found fewer shelters than we did at other sites. However,
this site is large and has great potential for further exploration. The swamp spans approximately
one and a half kilometres to the south and is over one kilometre wide. Van Teubner (0428 902
626), the property owner to the south of this site, spoke of several sites of Thatching Grass on
his property that are potential YSS habitats.
Recommendations This swamp should be revisited to better assess the Thatching Grass sedgelands. There was a
population of YSS in the area we surveyed despite the patchiness of the Thatching Grass. I
believe that a wide spanning search of this swamp, perhaps one full day, could reveal several
YSS populations.
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Site access map for Corny Point Swamp - north
Transects and quadrats at Corny Point Swamp - north
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9.2.2 Daly Head Swamps
Site name Daly Head
Land Manager Alan Wilson Landholder Contact 0428 434 534
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -35°1’47.1” Longitude: 136°58’18.5” E: 679876.4 N: 6121881.5 Zone: 53
Site access The site is one third down the west coast of southern Yorke Peninsula, approximately four
kilometres inland (east) from Daly Head. It is easy to access from Marion Bay Road, 15.6
kilometres south of its intersection with Corny Point Road or 24 kilometres travelling
north from Yorke Highway near Marion Bay.
Access to the site is 4.3 kilometres down Daly Head Road, a dirt track, on the western side
of Marion Bay Road. A large white mineral deposit will be visible on the northern side of
the road and a gate will give access to the swamp approximately 550 metres from the
intersection with West Coast Road.
Once through the gate, cross a small strip of cropped land and enter the
swamp/sedgeland.
Land use This land was historically grazed by sheep but the land manager claims it has remained
un-grazed by domestic animals for over 30 years. Our survey revealed high rates of
grazing by native animals and some sheep scat.
Transect selection At this site, transects started at the edge of the Thatching Grass sedgeland where it
bordered low-lying samphire vegetation. As always, transects were selected where the
sedgeland was at least 30 metres deep; apart from that locations were randomly located.
Transects surveyed 4 Mean larvae per quadrat (12 m2) 0.81 Total shelters 30
Quadrats surveyed 16 Potential larvae in transects 29.25 Total larvae 13
Size of habitat 10.4 hectares – in the immediate area surrounding the transects. The surrounding area is
most made up of native vegetation and is currently under Heritage Agreement (1424).
There appear to be more Thatching Grass scattered through this area, which could be YSS
habitat.
Site report and
notes
Composition: Gahnia filum sedgeland. Average height: 1.3 m. Average cover 35%. Over
rarely, Pimelea serpyllifolia, Frankenia pauciflora low shrubs, over open to mid-dense mat
plants of Wilsonia humilis, Samolus repens, Disphyma crassifolia, with open low mixed
native and introduced grasses: Rytidosperma spp., *Lagurus ovatus, *Avena barbata.
Occasional emergent medium and tall shrubs of Acacia cupularis and Melaleuca
halmaturorum. Dried up unidentified annual daisy common.
Soil: Cream silty clay. Salt crust possibly blue-green algae prevalent (~70%). In addition,
some moss cover. No rock. Litter low cover (5%).
Grazing: Significant grazing pressure noted on most plant types. Rytidosperma (up to
90% of plants either severely or heavily grazed). Gahnia: most plants lightly grazed,
almost half population heavily grazed. Exocarpos aphyllus: all plants either heavily or
severely grazed. Kangaroo dung common. In addition, some sheep dung.
Notes: This site had the median average density of larvae per quadrat. This suggests that
there is a healthy population but it is not flourishing as much as others (e.g. Balaklava
Road, Brutus Road sites). The heavy grazing noted may be affecting numbers because
both the YSS and large herbivores favour the young shoots at the outer edge of the
tussock. This could result in YSS eggs or larvae being eaten or dislodged.
Recommendations This site appears to host a healthy population of YSS though it is not as large as others
are. I classify this site as potentially suitable for low number sampling (compared to larger
populations). Satellite imagery suggests that there are more Thatching Grass sedgelands
to the north and east of this site. If this is true, the size(s) of the population(s), and the
respective density, could be greater. This site merits further investigation.
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Site access map for Daly Head Swamp
Transects and quadrats at Daly Head Swamp
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9.2.3 Balaklava Road site
Site name Balaklava Road site
Land Manager Stephanie Ball Landholder Contact 08 8854 5004
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -35°1’48.1” Longitude: 137°20’47.3 E: 714062.3 N: 6121109.7 Zone: 53
Site access This site is located approximately 10.5 kilometres south west from Warooka and half way
between Point Turton to the north and the south coast. Balaklava Road runs mostly east/west
between Yorke Highway and Wild Dog Hill Road to the west and Little Sheoak Road to the east.
The site is located 2.3 kilometres from Wild Dog Road and 1.4 kilometres from Little Sheoak
Road. It is 130 metres to the north of Balaklava Road, approximately 300 metres west of some
houses.
Land use The surrounding land is cropped. There was no knowledge of domestic grazing in the
sedgeland.
Transect selection This site is very large and seemed quite uniform in its structure from ground level i.e. Thatching
Grass sedgeland with no trees. Three transect were selected from the edge of the site (as most
other sites) but one was laid over 100 meters into the sedgeland. We did this to test if there
was a positive edge effect for that transect.
Transects surveyed 4 Mean larvae per quadrat (12 m2) 2.13 Total shelters 75
Quadrats surveyed 16 Potential larvae in transects 76.50 Total larvae 34
Size of habitat 52.2 hectares
Site report and
notes
Composition: Gahnia filum sedgeland. Average height: 1.4 metres. Average cover: 60%. Over
mid-dense tall and low mixed native (~10% cover) and introduced grasses (~5% cover):
Rytidosperma setaceae, Distichlis distichophylla, *Hordeum sp., +/- Austrostipa sp., and
abundant weedy herbs (~10% cover): *Dittrichia suaveolens. Occasional thistles: *Cirsium
vulgare. Occasional emergent *Lycium ferocissimum.
Grazing: Very little if any grazing at this site. Rytidosperma (very palatable grass) was not
touched. Only occasional kangaroo dung was seen.
Notes: This site had the highest count of larvae for the survey. A point of interest is that there
was no apparent preference between the ages of the tussocks. We found larvae on large
mature tussocks and we found larvae on small, young, knee-high tussocks (up to three larvae
on one) and this was not isolated to this site. A second point of interest is that there were no
trees for several hundred metres. There also appeared to be very few herbaceous flowering
plants that could act as a source of nectar; yet this site had the greatest amount of shelters and
the highest number of live larvae.
Recommendations This site appears to host a large population of YSS. It would be beneficial to return to this site
for a dedicated population survey to see if we were fortunate in landing in a ‘hot spot’ or if the
population spreads more or less consistently across the sedgeland.
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Site access map for Balaklava Road site
Transects and quadrats at Balaklava Road site
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9.2.4 Orrie Cowrie Road site
Site name Orrie Cowrie Road site
Land Manager Ron Hayes Landholder Contact 0419864856
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -35°1’47.1” Longitude: 136°58’18.5” E: 713783.1 N: 6123453.9 Zone: 53
Site access This site is located approximately 9 kilometres driving south west from Warooka and half way
(slightly northern) between Point Turton to the north and the south coast. Orrie Cowrie Road cuts
a NW to SE diagonal between Yorke Highway to the west and Little Sheoak Road to the east. The
site is located 3 kilometres from Yorke Highway and 1.8 kilometres from Little Sheoak Road. It is
130 metres to the north of Balaklava Road, approximately 300 metres north west of some houses.
Land use The surrounding land is cropped. There was no knowledge of domestic grazing in the sedgeland.
Transect selection Four transects were surveyed at this site, they were approximately 50 metres apart. The satellite
image shows a distinct difference between the top two and the bottom two, but this was not
noticeable or deliberate on the day.
Transects
surveyed
4 Mean larvae per quadrat (12 m2) 1.3 Total shelters 85
Quadrats
surveyed
16 Potential larvae in transects 47.25 Total larvae 21
Size of habitat 30 hectares in the immediate area with a further 30 hectares of potential habitat located closely
to the north.
Notes Composition: Gahnia filum sedgeland. Average height: 1.4 metres. Average cover: 35%. Over
mid-dense weedy herbs dominated by *Dittrichia suaveolens, over dense dead low weedy
grasses: *Hordeum sp. Occasional *Chondrilla juncea and *Sonchus oleraceus herbs.
Soil: Grey to light-brown cracking clay. Minimal calcrete rock, strew and litter. Some bare ground
but not much (~5%). Salt-crust extensive. Practically no moss lichen or microphytic crust.
Grazing: Some grazing on Gahnia filum around bases, perhaps ~10% heavily grazed, more
frequent near edge of patch. Kangaroo dung sparse. No sheep dung seen.
Notes: The southern-most section of this site appears different to the major part of this
sedgeland. There is currently no fence that separates the two but this could have existed in the
past, meaning that the southern section could have been exposed to different grazing pressures
than the rest. The southern section also appears to be more sparse and perhaps drier, as any
surface water would likely move to the north. The soil appeared quite friable and exhibited 3-5
millimetre cracks throughout. There also appeared to be greater dieback and leaf curling on
plants in the southern transects.
This site was drier but five larvae were found
on one tussock here, along with others. Five
was the highest density that we found on a
tussock.
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Site access map for Orrie Cowrie Road site
Transects and quadrats at Orrie Cowrie Road site
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9.2.5 Old Saltworks Road
Site name Old Saltworks Road site
Land Manager Julie Page Landholder Contact 0417 829 058
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -35°3’22.9” Longitude: 137°26’58.9” E: 723408.3 N: 6117962.4 Zone: 53
Site access This site is located approximately 11 kilometres driving south east from Warooka and in the
southern third of the narrowest section of south Yorke Peninsula. Orrie Cowrie Road cuts a NE to
SW diagonal between Tuckokcowie Road to the west and Saint Vincent Road (and Boundary
Road) to the east. The site is located 400 metres from the intersection of Gum Tree Road and
Old Saltworks Road, and 1.6 kilometres from Boundary Road. The site is quite dry, patchy and is
not a wetland. It has several scattered trees (mostly Melaleuca). It is on the northern side of Old
Saltworks Road.
Land use This site is periodically grazed by sheep.
Transect selection Four transects were surveyed at this site. Transects were between 40 and 50 metres apart. The
only consideration was that transects did not line up with established trees.
Transects surveyed 4 Mean larvae per quadrat (12
m2)
0.44 Total shelters 29
Quadrats surveyed 16 Potential larvae in transects 15.75 Total larvae 7
Size of habitat 3.3 hectares
Notes Composition: Gahnia filum sedgeland. Average height: 1.3 metres. Average cover: 20% (range
between 5-30%). Over dense low weedy grasses, dominantly *Hordeum sp. with occasional
patches of Wilsonia humilis and Disphyma clavellatum mat plants. Frequent low shrubs of
Melaleuca lanceolata - all severely grazed. Occasional emergent medium shrubs of *Lycium
ferocissimum. Patch fringed by Melaleuca lanceolata woodland (average height: ~5 metres) with
*Lycium ferocissimum common.
Soil: Grey-brown cracking clay. Minimal rock or litter. Crust: 40% and at least partially
microphytic. Large areas of bare ground ~40%.
Grazing: Melaleuca lanceolata low shrubs all severely grazed. All Gahnia filum grazed at least
lightly. Up to ~20% heavily. Some juveniles, severely. Sheep most likely because dung was
numerous.
Notes: This site had scattered tussocks of Thatching Grass (not a uniform sedgeland) and
several more trees than other sites. Inundation appeared to occur less frequently than other
sites and the satellite imagery supports this; it appears to be peripheral to the main swamp area.
The population density (mean larvae per quadrat) is similar to Corny Point Swamp – north,
matching with its plant density. This is reasonably good considering the density of the plants. An
active shelter was found on a tussock that had many dead leaves growing in dry and cracking
soil.
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Site access map for Old Saltworks Road site
Transects and quadrats at Old Saltworks Road site
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9.2.6 Little Moldarby Waterhole
Site name Little Moldarby Waterhole
Land Manager Julie Page Landholder Contact 0417 829 058
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -35°2’50.7” Longitude: 137°25’11.7” E: 720716.2 N: 6119022.3 Zone: 53
Site access This site is located approximately 8.5 kilometres driving south from Warooka and in the
southern third of the narrowest section of south Yorke Peninsula. It is best accessed from
Tuckokcowie Road, which runs north/south and approximately parallel to Sturt Bay Road, two
kilometres east of it. The site is located two kilometres south of Orrie Cowrie Road and 1.2
kilometres north from Gum Tree Road. The site can also be access if travelling west (from
Yorketown) along Old Gasworks Road (on to Gum Tree Road).
Land use There was no knowledge of domestic grazing in the sedgeland.
Transect selection Four transects were surveyed at this site, two on either side of Tuckokcowie Road. This was done
with the hope to record if there was any indication of difference in populations on either side of
the road. Each transect started near to the road’s edge.
Transects surveyed 4 Mean larvae per quadrat (12 m2) 0.50 Total shelters 40
Quadrats surveyed 16 Potential larvae in transects 18.00 Total larvae 8
Size of habitat There is approximately eight hectares of Thatching Grass sedgeland. However, this joins to
surrounding swamp that spans for an additional 30 hectares.
Notes Composition: Gahnia filum sedgeland. Average height: 1.2 metres. Average cover ~35%. Over
open patches of low samphire: Tecticornia pergranulata, T. indica, over patchy open low
introduced and native grasses: *Hordeum sp., Rytidosperma sp., Austrostipa sp., and mixed
introduced and native herbs: *Dittrichia suaveolens, native Compositae (finished), Goodenia
pusilla. Occasional emergent medium and tall shrubs of Nitraria billardieri, Myoporum insulare,
Melaleuca halmaturorum.
Soil: Light brown-grey hard-set cracking clay. Some calcrete rock, but not much, <1%. Quite a
bit of bare ground, ~40%, much of it with a sort of salt crust, which doesn't appear to be moss,
lichen, or microphytic.
Grazing: Some grazing observed but not a major impact. Gahnia: Light and occasionally heavy.
Rytidosperma: ~20% of population lightly grazed, ~5% heavily. Goodenia pusilla: ~50% lightly
and ~5% heavily. Kangaroo dung common, rabbit dung occasional
Notes: This site is very large and it is likely that the Thatching Grass sedgelands spans, at
varying density, for over eight hectares (adjoining to 30 hectares of surrounding swamp
potentially with Thatching grass). We ran transects on either side of the road due to the patchy
distribution of the Thatching Grass. The area surveyed is on the edge of low lying swamp that
spans up to the north east.
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Site access map for Little Moldarby Waterhole
Transects and quadrats at Little Moldarby Waterhole
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9.2.7 Brutus Road site - north
Site name Transects at Brutus Road site – north
Land Manager Chris Murdoch Landholder Contact 0419 869 028
NCSSA Contact Chris Butcher: 0406 226 296 or [email protected]
GPS coordinates Latitude: -35°1’47.1” Longitude: 136°58’18.5” E: 679876.4 N: 6121881.5 Zone: 53
Site access This site is very close to Point Turton, which is where the Yorke Peninsula coastline turns from
north/south to east/west. The site is near the north coast of southern Yorke Peninsula. It is 3.3
kilometres west on Brutus Road from its intersection with Point Turton / Bayview Road and 7.7
kilometres east from Point Soutter Road.
Land use This site is periodically grazed by sheep.
Transect selection Time constraints limited the number of transects we were able to survey. There was a clear start
to what appeared to be a dense and uniform sedgeland along the southern boundary of the
sedgeland. The two transects were approximately 45 metres apart and started at the edge of
the sedgeland.
Transects surveyed 2 Mean larvae per quadrat (12 m2) 1.63 Total shelters 46
Quadrats surveyed 8 Potential larvae in transects 28.25 Total larvae 13
Size of habitat 15 hectares is the approximate size of the sedgeland visible north of Brutus Road in the map
below. The sedgeland is broken by the road but continues to the south in a mostly continuous
but patchy sedgeland. The total potential area, including the sedgeland to the south of Brutus
Road, is over 70 hectares.
Notes Composition: Gahnia filum sedgeland. Height range from 2.0 metres near edge of patch to 0.8
metres near middle of patch. Average height: 1.2 metres. Average cover: ~50%. Understorey of
dense low samphire: Sarcocornia quinqeflora and mat plants of Disphyma crassifolium, with
occasional low weedy grasses of *Hordeum sp., *Rostraria cristata, Austrostipa sp., and some
introduced small herbs. Occasional emergent medium and tall shrubs of Myoporum insulare
and *Lycium ferocissimum. Rarely emergent small trees / tall shrubs of Melaleuca lanceolata.
Soil: Grey-brown cracking clay - hard setting. Significant calcrete outcropping and strew ~5-
10% of total ground cover.
Grazing: Very little evidence of grazing though kangaroo dung occasionally found.
Notes: Despite its appearance from the road, this site had a wide variety of tussock
characteristics and sedgeland structure. Tussock density and height were both high near the
southern edge of the sedgeland. Both density and height of tussocks lowered after moving 30
metres into the sedgeland where a large open area can be seen on the satellite image (below).
This image shows that there is patchiness of the tussocks but that there is a very large area of
potential YSS habitat.
A solar powered pump fills a well and overflows into the southern section of the sedgeland.
This produced a lush, green patch of Thatching Grass (just north west of the western transect)
with very green samphire species forming a dense ground cover.
The sedgeland to the south of Brutus Road is owned by Anthony (08 8853 4223) and YSS
continues at this site.
Recommendations I would like to survey transects along both of the longer western and eastern edges, and
perhaps in the centre along the drainage line. I am confident that this site, along with the
continuation of the sedgeland across Brutus Road, hosts a large population(s) of YSS. Further
population surveys would confirm this.
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Site access map for Brutus Road site - north
Transects and quadrats at Transects at Brutus Road site - north
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9.3 Appendix 3
Adelaide International Bird Sanctuary National Park - Winaityinaityi Pangkara
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9.4 Appendix 4
9.4.1 Data sheets
Site description data sheet used at Gahnia filum sedgelands on the southern Yorke Peninsula
SITE NAME
LAND MANAGER
CONTACT DETAILS
SEDGELAND SIZE
SEDGELAND SHAPE
TUSSOCK DENSITY
VEGETATION
COMPOSITION
SOIL TYPE
WEED PRESENCE AND
TYPE
EVIDENCE OF GRAZING
HYDROLOGY
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Data sheet to record details when shelters of Hesperilla flavescens (Yellowish Sedge-skipper)
were found on Gahnia filum tussocks on the southern Yorke Peninsula
SITE: SURVEY: TRANSECT: QUADRAT:
ACTIVE SHELTER yes no LARVA IN PUPATION yes no
LOC. OF SHELTER ON LEAF 1/4 2/4 3/4 4/4 MOVE ON IF LARVA IS IN PUPATION
LOC OF SHELTER ON
TUSSOCK LARVAL GENDER male female
HEIGHT OF TUSSOCK (m) < 0.5 0.5 - 1 1 - 1.5 > 1.5 APPROXIMATE INSTAR 1 2 3 4 5
WIDTH OF TUSSOCK (m) < 0.5 0.5 - 1 1 - 1.5 > 1.5 EVIDENCE OF PARASITES yes no note:
LEAF HEALTH (% DEAD) < 25 25-49 50-75 > 75 TOTAL LARVAE FOUND ON TUSSOCK
WAYPOINT TAKEN yes no NOTES:
FLAGGING TAPE TIED yes no
OTHER SHELTER ON TUSSOCK yes no
OTHER SHELTER ACTIVE yes no