Yellowish Sedge-skipper butterfly fact sheet For reintroduction in the northern Adelaide coastal plains

Every animal and plant plays a part in shaping where we live, work and

play. When the Yellowish Sedge-skipper butterfly became regionally extinct

from the northern Adelaide coastal plains it could no longer play that part

(i.e. pollinate flowers). Bringing it back will not only restore what it used to

do in the region, it will allow many other native plants and animals to play

their parts. In some cases, native insect species can even control major

horticultural pests.

Restoring a habitat for a species that can no longer survive there has many

potential benefits for native biodiversity, local communities and horticultur-

alists. The habitat must be healthy for the species to return and remain but

this requires the cooperation of many people in the community.

Why reintroduce a butterfly?

Which butterfly? Which habitat?

Thatching Grass sedgelands

- Long lived

- Low maintenance

- Habitat for native animals

- Host predators that control thrips

- Tolerates flooding & drying

- Tolerates fresh to brackish water

The Yellowish Sedge-skipper (Hesperilla flavescens

- Fig. 1), used to flourish in the northern Adelaide

coastal plains. It has not been seen in the area

since 1985 and is believed to be regionally extinct.

It lives in Thatching Grass (Gahnia filum)

sedgelands (Fig. 2), which used to be common in

the region. It now lives in sedgelands in south

eastern Australia ranging, in isolated patches, from

Eyre Peninsula to south west Melbourne, Victoria.

The Nature Conservation Society of South Australia

is working with Natural Resources Adelaide & Mt

Lofty Ranges and BirdLife Australia to restore the

habitat of this butterfly and reintroduce to its

historic range. Yellowish Sedge-skippers

- Close to 3 cm wingspan

- Larval stage lasts 1 yr

- Impetus to restore native

habitats

- Increase native biodiversity

- Attraction for nature lovers

Figure

1: H

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The Yellowish Sedge-skipper study is part of the Samphire Coast Icon Project, supported by the Adelaide

and Mount Lofty Ranges Natural Resources Management Board through funding from the Australian Government.

Figure 2: Male YSS specimens from the top (above) and underwing

(below) and a healthy Thatching Grass tussock. Photo: C. Butcher

Figure 3: Late instar YSS larva. Photo: C. Butcher

Benefits to horticulturalists

Benefits to communities

Horticultural 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 Western Flower Thrip

(Frankliniella occidentalis), which damages crops directly and also transmits

Tomato Spotted Wilt Virus (Fig. 4).

Thatching Grass sedgelands host native predatory and parasitic insects that

target these thrips. A study revealed that these insects, Eulophid Wasp

(Ceranisus menes ) and Scelionidae Wasps (Telenomus spp.), can be used as a

biocontrol agent that have no known negative impact on crops. The study also

revealed that Thatching Grass is also not attractive for the thrip to seek refuge

like weed species are (Wood and Coleman, 2016).

Horticulturalists that adopt Thatching Grass around their enterprises as part of

an integrated pest management solution could save a great deal of money.

Everybody loves butterflies! The northern Adelaide coastal plains is full of

environmental treasures that are waiting to be promoted. The region has the

Adelaide Dolphin Sanctuary and the newly proclaimed Adelaide International

Bird Sanctuary National Park - Winaityinaityi Pangkara. Furthermore, another

butterfly species being restored in the region, the Bitterbush Blue (Theclinesthes

albocincta). With enough community and government support, starting with

these butterflies, the region could become a butterfly hotspot.

Engaging local schools, community groups and volunteer organisations to get

involved in conservation and habitat restoration projects to bring back the

butterfly will instil a sense of ownership in the land and further promote

environmental stewardship for the region. It will also improve visual amenity

and increase native wildlife, attracting nature lovers to the region, which will

also support local communities and businesses.

Areas of interest The areas of interest are on low-lying wetland

habitats in the northern Adelaide coastal plains

spanning from the Port River Expressway to north of

Two Wells (Fig. 3).

Thatching Grass is suited to low, relatively flat and

open areas (not shaded) that can be seasonally

flooded (fresh water).

The more Thatching Grass sedgeland like this in the

area, the better chance we have of bringing the

butterfly back and maintaining their presence.

There are currently several areas of Thatching Grass

sedgeland that are being restored, protected and

expanded. These sedgelands are both on private and

public land. Each site is unique and requires its own

management plan.

Adelaide CBD

Figure 3: The northern Adelaide coastal plains; part of the former habitat

of the Yellowish Sedge-skipper and Thatching Grass sedgelands

Figure 4: Above: Frankliniella

occidentalis (Western Flower Thrip).

Photo: Lyle Buss. Below: tomatoes

infected with Tomato Spotted Wilt

Virus (photo: anon).

Figure 5: Mature Thatching Grass

tussocks amongst planted seedlings at

Salisbury Greenfields 3 Wetlands

Photo : C. Butcher

Creating a butterfly habitat

One of the best way to create a habitat for this butterfly is to have an existing healthy patch of Thatching Grass

tussocks, which can be added to. The Yellowish Sedge-skipper relies on Thatching Grass* to lay its eggs; its larvae

survive on its leaves until it emerges as a butterfly. Thatching Grass grow in a variety of soil types and thrive where

fresh to brackish water pools over winter and may dry out in summer (Coleman and Coleman, 2000).

They can be planted with close spacing (0.5-1 m) in full sun but close to native flowering trees (Fig. 6 & 7). The

butterfly prefers open and flat sedgeland for mating displays. Females need clear accesses to the side of the

tussock to lay their eggs (Fig. 7). Habitats for this butterfly can be quite small. Populations are known to breed on

clumps of only 150 plants (30 young) (Alex Stolarski pers.com. 2017).

What to look for

Figure 6: Guarded Gahnia filum (Thatching Grass) seedlings at

Salisbury Greenfields 3 Wetlands Photo: C. Butcher

Figure 7: Small natural Thatching Grass sedgeland with Melaleuca

trees on Yorke Peninsula. Photo: C. Butcher

Figure 8: A large Hesperilla flavescens shelter made between

three or four Gahnia filum leaves. Photo: C. Butcher

Figure 9: A Hesperilla flavescens larva, fifth instar, this will

pupate (metamorphose) in 1-2 months. Photo: C. Butcher

*Also Gahnia deusta (Heathy Saw-sedge)

Once the butterfly is reintroduced to the region we will start to see signs of it in the sedges. We anticipate they

will spread across the region where habitats are suitable. You will know if you have this butterfly in you park or on

your property if you find one of its shelters (Fig.8). The larvae create shelters between the leaves of the Thatching

Grass where they spend their days protected from the elements and predators. They emerge at night to feed.

The larva will build a shelter to suit its current growth phase (instar) (Fig. 9). It’s common to find 1-2 old shelters

on a tussock. Shelters are normally on the outer leaves of a tussock and they’re usually made between fresh,

green leaves.

Yellowish Sedge-skipper fact sheet

More information

Councils, state government, NGOs and community groups: Local and state government agencies are working together with

non-government organisations and community groups to help improve the Thatching Grass habitat for the Yellowish Sedge-

skipper. Visit their websites or offices to discuss what you want to know or how you can help.

City of Salisbury, City of Playford and Adelaide Plains Council

Natural Resources Adelaide Mt Lofty Ranges

Nature Conservation Society of South Australia (NCSSA)

Management plans and projects: One of the founding documents for this effort is the “Local recovery plan for the Yellowish

Sedge-skipper and Thatching Grass” (Coleman and Coleman, 2000). The Local Recovery Plan helped lead to the inclusion of

this butterfly and its habitat as conservation priorities in the Metropolitan Adelaide and Northern Coastal Action Plan (2009).

The Local Recovery Plan was reviewed in 2015 to see how close we were to reaching our goals. The NCSSA has completed a

feasibility assessment for the reintroduction of the species (Butcher, 2017).

Coleman, P & Coleman, F (2000) Local recovery plan for the Yellowish Sedge-skipper and Thatching Grass. Saint Kilda, South Australia: Delta

Environmental Consulting.

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.

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.

Butcher, C (2017) Yellowish Sedge-skipper Butterfly Reintroduction Feasibility Project – Final Report. Prepared for the Nature Conservation

Society of South Australia for the Adelaide and Mt Lofty Natural Resources Management Board (Samphire Coast Icon Project).

Specialist pest management research: There is some very promising research examining using native plants (and animals) as

part of an integrated pest management strategy. This is specifically targeted at common horticultural pests. Read the

following reports for more information.

RIRDC (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.

Wood, G and Coleman, P (2016) Gahnia filum: Insect use of Thatching Grass. Prepared for: Adelaide and Mt Lofty Ranges Natural Resource

Management Board.

Other research from the literature: There has been a great deal of work on butterfly conservation in Australia, including the

close relative Hesperilla flavescens flavescens in Victoria.

Braby, M (2000) Butterflies of Australia: Their Identification, Biology and Distribution. CSIRO Publishing.

Grund, R (1997) Interim Recovery Plan. Recovery of Hesperilla flavescens flavia (Lepidoptera: Hesperiidae), the yellowish skipper. Report to

National Heritage Trust, Canberra.

Grund, R (2003) The yellow sedge-skipper on Yorke Peninsula. Prepared for Butterfly Conservation South Australia Inc.

New, T (2011) Butterfly conservation in South-Eastern Australia. 1st ed. New York: Springer, pp.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.

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), pp.143-149.

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.

Email: ncssa@ncssa.asn.au | Phone: 08 7127 4630