Salinity may be the environmental threat that’s top-of-mind among many Western Australians, but dieback is quietly carving a swath of destruction through forests and bushland in the South West, seriously affecting the biological diversity of the native ec
Salinity may be the environmental threat that’s top-of-mind among many Western Australians, but dieback is quietly carving a swath of destruction through forests and bushland in the South West, seriously affecting the biological diversity of the native ecosystem and causing major headaches for industry.
Phytophthora cinnamomi, also known as ‘plant destroyer’, is a water mould that attacks the roots of susceptible plants in areas receiving rainfall more than 400 millimetres a year, eventually killing them by limiting their uptake of water and nutrients.
Up to 40 per cent of the estimated 5,700 plant species in WA are known to be susceptible to dieback, a soil-borne pathogen spread when infested soil or root material is transferred to vulnerable areas via vehicle, bicycle or human movement.
Dieback Working Group project officer Dr Chris Dunne is leading the fight against dieback, which has spread as far north as Jurien and south through to Esperance.
DWG was formed in 1996 to identify areas of remnant vegetation at risk of dieback, map disease occurrence, develop management and treatment plans, and raise awareness of the disease among land managers and the public.
Dr Dunne said the DWG comprised representatives from community conservation groups, local government authorities and state government agencies, and had occupied an office provided by the Shire of Kalamunda since 1998.
At the recent Dieback Information Group’s annual conference, scientists revealed the discovery of three new species of Phytophthora in WA, two of which could be new to science and appear to be air-borne.
“Research is continuing to find out whether these are in fact new beasts, or if it’s a case of misidentification,” Dr Dunne told WA Business News.
“Researchers are using a DNA fingerprinting technique developed by Murdoch University to compare species and establish which plants could be affected.”
Dieback is thought to have been introduced on fruit trees soon after European settlement, and has since infected national parks, nature reserves and metropolitan bushland.
More than 20 per cent of WA’s jarrah forest and around 60 per cent of the 116,000-hectare Stirling Range National Park, near Albany, are affected.
In other places, about 70 per cent of the banksias woodlands in the 170,000ha Shannon and D’Entrecasteaux National Parks, between Augusta and Walpole, have been infected and DWG is working with local groups to stop it spreading further.
An injection of a chemical called Phosphite into tree trunks or spraying the chemical over infected areas are the most effective treatment methods.
This year, the federal government has allocated $1.5 million to the fight, while the DWG is in the process of making a proposal to the state government for more funding.
Dr Dunne estimated funding of between $30 million and $40 million was needed over seven years in order to protect areas at risk and rehabilitate infected areas in the South West.
The disease is estimated to cost the Australian economy about $160 million a year, and is reportedly pushing some species of flora and fauna to the brink of extinction.
DWG suggests the battle can only be won with continued funding and greater community understanding, beginning with making the decision to buy plants from accredited nurseries, to minimise the spread of dieback to suburban gardens.
