Never Say Dieback

Alan Elliott and Neighbour Val Thompson discussing last year’s dieback treatment with Chris of Dieback Treatment Services and PHCC’s Land Conservation Officer Jordon Garbellini.

We recently supported landholders in Serpentine and Keysbrook in their efforts to combat a Phytophthora Dieback infestation threatening Banksia Woodland on their properties.

This included a large patch of bushland spread over three properties, of which the Elliott family own a portion. Alan and Marrion moved to their 128 hectare Keysbrook property in 1985. They have been custodians of their patch ever since, wasting no time in getting on board with stewardship programs including Land for Wildlife, Healthy Habitats, and Conservation Zoning under the Shire of Serpentine-Jarrahdale’s local planning scheme. In 2005, the property was listed under a Conservation Covenant through the National Trust, ensuring long-term, formalized protection of the property’s natural assets into the future.

Land disturbance, drainage and clearing across surrounding districts on the Swan Coastal Plain over more than a century has resulted in areas of remaining Banksia Woodland, such as the Elliott’s patch, becoming isolated from one another. Many of the remaining island pockets of woodland are at high risk of weed invasion, Phytophthora Dieback, and feral animals.

The listing of Banksia Woodlands of the Swan Coastal Plain as a Threatened Ecological Community, due to the 60% decline in its original extent, heightens the importance of protecting the 80 hectares of Banksia Woodland found on the Elliot’s property. The bushland patch is known to support 233 recorded plant species and over 60 bird species including the endangered Carnaby’s Cockatoo and the threatened Red-Tailed Black Cockatoo.

Despite its relatively large size and dedicated custodians, the site is not immune to the pathological threat: Phytophthora Dieback: an aptly named natural bulldozer which is listed as a key threatening process under the Commonwealths EPBC Act.

As a child exploring the property, which then belonged to his father, Alan and his siblings took note of several bare areas in amongst the woodland. Not being aware of Dieback at the time these areas remained a curiosity until unexplained plant deaths in the early 2000’s triggered a site visit from Landcare SJ who undertook sampling to determine the cause, thus beginning the Elliott’s battle to address the threat posed by Dieback.

A comprehensive Dieback treatment routine was adopted, with a Phosphite foliar spray taking place bi-annually and stem injections occurring every four years. Attempting to undertake the initial round of treatment along the 9km Dieback front themselves, the Elliott’s soon realized that the rigorous process was extremely time and labor intensive and brought in the experts.

Since its initiation, the treatment routine has been refined to align both foliar spraying and stem injection on a three yearly basis. As the process is time consuming and costly, the property has been divided into three sections that are treated on rotation, one round of treatment occurring each year. PHCC were able to assist with the Elliott’s Phytophthora Dieback treatment for 2019 through a Community Environment Grant, supported through funding from the Australian Governments National Landcare Program. Two neighboring properties were also awarded grants to assist in mapping and treating Dieback affected Banksia Woodland, with the combined bushland totaling over 100 hectares.

There is not cure for Dieback, though the application of Phosphite through the process of stem injection and foliar spray has been scientifically proven to control the impacts caused by the pathogen. In the case of the Elliott’s property, recent re-assessments of the active infestation edge have shown promising results, with one area recording no new deaths for ‘the past 10 years, in addition to natural regeneration of Banksia species (known to be susceptible to Dieback).

The Elliott’s live in hope for the future of Banksia Woodlands and encourage others tackling Dieback to push on with their management efforts. Their advice: be patient as these things take time and perseverance and meanwhile enjoy your bushland.

This project is supported by the Peel-Harvey Catchment Council through funding from the Australian Government’s National Landcare Program