Mimosa Pigra: Weed of National Significance

A field day to discuss the latest weapons in the war against Weed of National Significance Mimosa Pigra was held at Elizabeth Downs Station in the Douglas Daly on September 3, 2009.

The event was attended by cattlemen, land council representatives, Aboriginal rangers, traditional owners, environmentalists and government officials and prompted an in-principle agreement for the Northern Territory Cattlemen’s Association to lead a co-ordinated funding pitch to Government to tackle the weed on an all-of-catchment basis.

Organised by the NTCA, the field day featured presentations by the National National Mimosa Coordinator Kay Bailey, Sue Whatley of Bushfires NT, Sally Heaton of the Department of Natural Resources, Environment and the Arts (feral animal impacts), Caroline Biggs of the NT NRMB (mimosa management in the Douglas Daly catchment) and Sky View Solutions (using un-manned aerial vehicles as a property management tool).

The field day was a Caring for Country project.

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Doug Chesson, Manager of Elizabeth Downs Station.

“You look at all this country around here - we’re pretty much surrounded by a seed bank.

“Every high tide, every wet season, there’s going to be a reinfestation of some degree.

“If they’re not going to do anything upstream, you can work until you’re blue in the face trying to control this stuff yet every wet season you’re going to be back to where you started from.

“The Aboriginal communities are faced with the same problem as pastoralists, that’s why they’re represented here today.

“A lot of their waterholes are choked out with Mimosa.

“This has to be an integrated, holistic approach - everyone has to get on board or anything you do will only be superficial. It’s never going to be a long-term, sustained control program

“When the rest of Australia thinks of the Northern Territory, they think crocodiles, barramundi, natural ecosystems - they think Kakadu.

“But this is the same sort of eco-system. It’s a unique and beautiful part of the world – whether you’re running cattle or taking photos of it.

“At the end of the day, unless these people who are making the decisions in Canberra actually witness this problem first hand – have to walk or crawl through this stuff and are confronted by the scale – they are never going to have an understanding of it like the people who deal with it every day.

“If mimosa gets out of control, you’d just about throw your hands in the air. It would be on such a scale it would almost be easier to walk away.”

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Margie Daiyi, Traditional owner and executive on the Northern Land Council. Margie has battled mimosa on Twin Hill Station for the past 14 years, spending 10 of those on the ground control team manning a spray unit herself.

“Twin Hill was classed as a basket case in 1996.

“We had nothing – we started off with an old bull catcher with no roof, working eight-nine hours a day.

“We began at Buffalo Hole, which was a single catchment. We hit it with everything we possibly could –sprayed it, got bulldozers in, chained it, hit it with napalm.

“The following wet season the grass grew and we’ve been maintaining control ever since.

“From there we started working through all the top catchments, then sprayed big areas out on the flood plains. We had government ‘dozers chaining and burnt when we could, where we could.

“I’m very proud of what we have achieved.

“You look out there now and you’d think there was never mimosa there, but you’re never going to get rid of it completely – everyone knows that – so we’re still doing ground control.

“I’m here as a traditional owner. In the past we’ve pushed for Northern Land Council to make people aware of the dangers of losing their country to mimosa. We nearly lost ours (at Twin Hill) - but we worked hard to get where we are today.

Margie also backed the idea of a co-ordinated pitch to government to fund a whole-of-catchment strategy to fight mimosa.

“I think this (a co-ordinated pitch to government to fund a whole-of-catchment strategy to fight mimosa) is a good idea.

“And it’s good to see everyone represented here today – the Pepe crew, the Wadeye/Thamarrrurr mob, the Malak Malak mob – it’s showing that they’re interested in what’s happening.

“I hope it’s the answer.”

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Luke Bowen, Executive Director, Northern Territory Cattlemen’s Association

“This is one of the first times we’ve seen such a range of people coming together to look at ways of tackling mimosa in the Top End – across aboriginal land, pastoral lease, crown land and other tenure.

“We saw aboriginal rangers, aboriginal landholders, pastoralists, a range of government experts all sharing the same common interest in defeating this weed.

“Everybody acknowledged it was time to get smart about it and co-ordinate our activities across all areas, starting at the top of each catchment, in order to get effective control.

“There is too much at stake to continue with management plans that are disjointed and ineffective in the long term.

“You only have to look at the maps of the potential areas where mimosa could take hold to realise that the current outbreaks are just the tip of the iceberg.

“We could have mimosa invade large portions of Queensland and Western Australia in addition to the areas it currently exists in the floodplains of the Top End of the Northern Territory.”

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Mimosa Pigra was introduced from tropical America to the Royal Darwin Botanic Gardens in the 1800s as a curiosity. It escaped into the Adelaide River catchment and is now spread throughout the Top End.

It is a prickly, branched shrub that grows up to six metres high and forms dense, impenetrable stands with little to no understory.

It thrives in wet areas such as river banks and coastal/flood plains.

It is listed as a Weed of National Significance in the NT, Queensland and Western Australia, which means is has highest priority status for prevention of infestation and spread.