Back from the brink Propagating Thatching Grass at the City of Onkaparinga Nursery. Searching for butterfly pupae in the state's south-east. Butterflies are released at Aldinga Washpool.
9 April 2020

Back from the brink

The Yellowish Sedge Skipper butterfly was last seen on the Adelaide Plains around the late 1980s, as habitat loss and insecticide-use saw it disappear from its coastal wetland habitats.

Last month, a 20-year project to reintroduce the locally extinct species has paid off, with the small yellow-and-brown butterflies being released into the Aldinga Washpool, among other sites.

“The butterfly relies on a plant, a sedge called Thatching Grass (Gahnia filum), which was extensively cleared from Adelaide’s coastal plains to make way for housing and agriculture,” says Tony Flaherty, Coast and Marine Manager with Natural Resources Adelaide and Mt Lofty Ranges, which leads the project.

“Intensive replanting efforts have gone on for many years in low-lying wetlands such as the Washpool at Aldinga Beach and at restored sedgelands in the Salisbury wetlands and near Waterloo Corner, in northern Adelaide.”

Tony says the need to conserve insects and other less obvious or charismatic species is sometimes overlooked, but they are just as vital for our environment as other species.

City of Onkaparinga’s parks and natural resources team has been instrumental in the replanting and restoration to make the Washpool – a highly significant ecological site that also holds great significance for the Kaurna people – ready to support the butterflies.

“Council has been working closely with Natural Resources Adelaide and Mt Lofty Ranges over the past decade on high-value biodiversity sites throughout the Onkaparinga region,” says City of Onkaparinga Coast and Estuary Technical Manager, Kerri Bartley.

“The aim is to increase native plant species cover and diversity to provide critical habitat for our native insects, animals and birds as well as mitigate erosion.

“The Aldinga Washpool is one of those sites where many years of ecologically important work has been undertaken, such as controlling declared woody weeds like olives and boxthorns, as well as smaller herbaceous weeds, which outcompete the many rare and endangered native plants recorded on the site.

“Council’s nursery is currently growing 2,000 locally sourced Gahnia filum seedlings this year, which were recently propagated by council volunteers to be planted in and around the Washpool.

“These plantings will complement the five-year Aldinga Washpool Revegetation Project, which is currently in its second year of planting.”

In February, council staff joined volunteers and NRM staff on a trip to collect pupae (butterflies in their development stage) from the state’s south-east, where the species still hangs on.

One-hundred pupae were carefully collected before being held in individual containers at the homes of council staff and volunteers. They’re being released into the Washpool as the butterflies emerge.

In positive signs, a project volunteer witnessed a pair of butterflies mating just days after the release, so council staff are hopeful the project’s success will continue.

“We just need to hope the females will successfully lay eggs on the surrounding sedges and, in time, we’ll see the first generation of ‘locals’ emerge at the Washpool next year,” says Kerri.

“In the meantime, we’ll continue to plant more Gahnia filum sedges and other important native plants in and around the Washpool and Onkaparinga Estuary, as well as other important wetlands throughout the City of Onkaparinga, to encourage and increase our biodiversity, healthy habitats and functioning ecosystems.”

If you’re interested in becoming a volunteer, either in City of Onkaparinga’s nursery or with our community planting and Bushcare sites, visit our website.

The Yellowish Sedge Skipper project began in 2000 by the South Australian Urban Forest Biodiversity Program, and a recovery plan was developed. Efforts were reinvigorated from 2012 with additional funding from the Australian Government and Adelaide and Mount Lofty Ranges Natural Resources Management Board to restore coastal butterfly habitats in the region.

Yellowish Sedge Skipper

Photo: Alex Stolarski

Green thumbs

Propagating Thatching Grass at the City of Onkaparinga Nursery.

On the hunt

Searching for butterfly pupae in the state's south-east.

Re-wilding

Butterflies are released at Aldinga Washpool.

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