WA government accused of inaction over arum lily infestation in southern forests

A picturesque view of white lilies carpeting the forest floor south of Margaret River belies an ugly reality for conservationists. The arum lily, considered one of the most damaging weeds in the country, has been banned from sale in Western Australia for over 20 years, yet its infestation of forests across the South West shows no signs of slowing.

Forests under threat

In Boranup Forest, 300km south of Perth, Obelia Walker has mapped an enormous arum infestation through her work with Nature Conservation Margaret River. The organisation is coordinating a three-year effort to help private landholders control the spread of lilies on their properties, funded by the state government. While these efforts have been successful, Walker is worried about the infestation on public land.

"If you think about where the majority of diversity happens in the forest, it's in the understorey," she said. "The way the arum lily behaves when it gets out of control like this is it's just smothering the understorey, out-competing native plants and destroying habitat for wildlife as well."

The arum lily infestation is worsening in the Tuart Forest National Park, near Busselton, conservationists say. Local volunteer Des Donnelly has petitioned the government to do more about the national park infestation. "It's probably worse than it ever was," he said. "If we don't manage them, we can probably kiss [the forest] goodbye in the next 50 years."

Mr Donnelly was behind a petition presented to state parliament earlier this year, calling for government agencies to do more to fight the flower in the forest. "It's a token effort if you like; Main Roads do a little bit, DBCA do what they can do with their small budget," he said. "Generally, we're only just fiddling around the edges."

March of the arum continues

The state government's focus is on controlling arum lilies in priority areas, rather than trying to eradicate the plant, prompting criticism from conservationists. A state government spokesperson said eradication was not realistic, with more than $2.6 million granted to arum lily control programs across the South West over the past nine years.

"While arum lily can be managed, it is not currently considered feasible to completely eradicate the species from the landscape due to its extensive distribution and ability to regenerate and spread," the spokesperson said. The spokesperson said it had undertaken control across areas in the Tuart Forest National Park, Leeuwin-Naturaliste National Park, Wooditjup National Park, Yelverton National Park, and selected state forest and nature reserve sites.

Creative solutions required

Conservationists agreed that the National Biosecurity Committee's inclusion of the arum lily on its list of Nationally Established Weed Priorities could lead to more innovative methods of control. Nature Conservation's Obelia Walker hoped it would unlock funding for research into more cutting-edge methods to tackle the weed. "We can't spray out way out of this problem," she said. "It might be something quite novel; it might be a fungus or a disease, but it's an exciting space."

Invasive Species Council policy director Carol Booth said the war on the lily was ultimately reliant on political will. "I mean, the arum lily is one of the classic examples in Australia of a garden plant that's just gone rogue," she said. "Which of these weeds are our state and federal governments prepared to put funding into to generate a much more collaborative and concerted approach to managing their risks?"