Restoring our roadsides
Earlier this year, Blewitt Springs residents Becky Hirst and Dan Procter called council about the narrow weed-choked lane alongside their property, which they thought might be a fire hazard.
They were pleased to receive a call from Ben Moulton, City of Onkaparinga’s Senior Natural Areas Conservation Officer, days later.
“I was so impressed that within days his team had looked at their mapping system and knew this was a woody weed hotspot, and he’d been in touch with Dana [Miles, Communication and Engagement Officer – Hills and Fleurieu Landscape Board],” explains Becky.
“Dana helped me understand that some of the trees are worth freeing.”
Weeks later, the lane’s long stretch of Pink Gum (Eucalyptus fasciculosa) woodland was being freed from a dense infestation of feral olive trees, which are a significant bushfire hazard and a major pest plant that displaces native species and damages habitat for native wildlife.
“The visual impact was immediate, with streams of sunshine now filtering through the canopy to the understorey, revealing the gnarled shapes of the Pink Gum branches,” says Ben Moulton.
“With some follow-up bush regeneration work, smaller native species will now benefit from the additional light and space, including Drosera planchonii (Climbing Sundew) Tricoryne elatior (Yellow Rush-lily) and regenerating Xanthorrhoea semiplana (Yacca).
Becky says she’s not only impressed by the lane’s visual transformation and reduced bushfire risk, she’s pleased for the native bird species that call the lane home.
“It’s an absolute haven for so many species of local birds so it’s going to be a treat watching them thrive with the olives gone,” she says.
The project is part of council and Hills and Fleurieu Landscape Board’s Free the Tree initiative, which aims to remove woody pest species that smother and threaten important trees, and to educate the public about the value of native vegetation and old remnant trees.
Woody weeds have also been removed from around Old River redgums, Grey Box, SA Blue Gums and Drooping Sheoaks across the Willunga Basin, and Dana says it has been extremely satisfying to see the trees’ health improve and new growth sprouting from previously shaded limbs.
“The installation of bright eye-catching signage prior to woody weed removal has generated great interest as the community can watch the progress like a before-and-after health promotion,” Dana says.
The initiative is just one facet of a 10-year partnership with the Hills and Fleurieu Landscape Board (part of the former Adelaide and Mount Lofty Ranges NRM Board) to protect Onkaparinga’s 1200 kilometres of roadside vegetation, helping biodiversity bounce back and reducing bushfire risk across the region. Achievements include:
- Establishing woody weed control zones on more than 480 kilometres of rural roadsides, which are revisited annually to control regrowth.
- Protecting and restoring more than 120 kilometres of native vegetation across 120 sites as part of a statewide roadside marker system of blue and white posts, including council signage to discourage spraying and dumping.
- Mapping and controlling high-priority weed infestations such as African lovegrass and Texas needlegrass each year.
The natural areas conservation team’s efforts have been bolstered by advances in GIS technology, allowing them to collect data on their smartphones to create weed-distribution maps and use the data to develop effective control strategies.
“We’ve now mapped locations and infestation levels of woody weeds – such as feral olive, boxthorn and briar rose) across more than 1100 kilometres of our roadside, providing us with a clear picture of what we’re dealing with,” says Ian Hockley, City of Onkaparinga’s Trails and Roadside Vegetation Officer.
“Using this data, we’ve applied criteria to help us prioritise what areas we target, including how high the fire risk is, whether the area contains important native vegetation and whether it’s adjacent a conservation reserve.”
City of Onkaparinga’s work with the state government is critical to successfully deliver annual rural roadside projects, but it also relies on local communities.
Working with landholders is vital because private property often sits alongside rural roadside native vegetation, and fence lines don’t prevent the spread of invasive weeds.
City of Onkaparinga also supports the Wine Grape Council South Australia’s EcoVineyards project, incorporating native insectary plants (which attract insects beneficial to pest control) in biodiverse ecosystems around vineyards.
The project, which includes three McLaren Vale wineries, hopes to reduce running costs and the use of chemicals, increase appeal to tourists and international wine customers, and contribute to biodiversity corridors (which allow animals to travel from one patch of native forest to another).
“By exploring ways our local native plant species contribute to vineyard health and ecosystem processes, our community is recognising that the protection of native vegetation also makes economic sense and is critical for the long-term sustainability of our region,” says Ben.
The fight for Onkaparinga’s roadsides is ongoing. Feral olive trees, for example, remain on 20 per cent of the city’s rural roadsides.
With the state government and community’s continued support, there’s hope the battle will be won.
Free the Tree
City of Onkaparinga's Ian Hockley, Hills and Fleurieu Landscape Board's Dana Miles and Blewett Springs resident Becky Hirst inspecting a lane cleared of feral olive trees.