[ASC-media] Media release: silent invasion

JCA Media jca.media at starclass.com.au
Mon Oct 23 23:06:01 CEST 2006

Cooperative Research Centre for Australian Weed Management

Media Release 06/12

October 24, 2006


Scientists from the Cooperative Research Centre for Australian Weed Management say that the lack of a strong early warning network to detect new plant invasions before they take hold is a matter for national concern.

In NSW alone between 2002 and 2005, 119 new species of foreign plants were recorded as 'naturalised' - i.e. making themselves at home and reproducing unaided.

Forty-seven of these were new records for the Australian flora. Some are real threats to native landscapes and others to agricultural production. The story is similar in all states and territories.

According to the Weeds CRC's and NSW DPI's Dr John Hosking, an authority on Australian flora, the lack of trained observers means that no one may even know about the next plant invader until it is too late. 

Dr Hosking and his colleagues are responsible for collecting and obtaining accurate names for many of the recently detected naturalised plant species in New South Wales.

"Early detection of new invaders is vital," says Dr Hosking. "Most weeds appear around human population centres, so this is where detection needs to occur. However, many 'new' invasive species are already lurking in our country and simply haven't been recognised."

To successfully control invaders it is vital that the correct remedy be applied to the correct pest, says Dr Hosking.

If a herbicide fails to knock back a weed, it may not be because the plant has developed resistance, but simply because it was wrongly identified.

"There are too many uncertainties in the identification process," says Dr Hosking. "In the first instance, there may be local and international confusion about which plant is which. Even taxonomists, who are specialists in accurate naming, may use different names in different countries."

Dr Hosking says that botanical research in Australia has concentrated on native species, and that detailed knowledge of invasive plants often relies on information from overseas which may be inaccurate, contradictory, or inapplicable. 

"Plants which have a familiar name in Australia may have a different name overseas," he says. "Or sometimes the same name may be used for what are really two different species, which can confuse everyone.' 

"This is a world-wide problem, not just confined to Australia," says Dr Hosking. "There's a global need for consistency in naming and describing plant species."

Dr Hosking says that undesirable plants can enter Australia by a variety of loopholes, inadvertently or illegally.

"Early detection is essential," he says. "It is much cheaper to eradicate something which has colonised a small area, rather than after it has become widely established."

Dr Hosking cites the case of Siam weed (Chromolaena odorata) which had colonised twenty kilometres alongside a Queensland river before it was accurately identified.

"Local people called it 'giant billy-goat weed' because it resembles a common knee-high weed. But this invader was growing as high as the tops of small trees. Attempts at eradication have now cost over three million dollars."

Dr Hosking says that Australia is suffering from a serious lack of trained observers capable of detecting new invaders before they become seriously established.

"Volunteer groups have done a great job weedspotting and assisting control programs, but they are not usually sufficiently expert to identify dangerous newcomers," he says. 

Weedspotter groups, council weed officers and even identification staff at herbaria cannot be expected to be specialists of the entire world flora and be able to identify large numbers of specimens correctly, especially if only parts of the plant are present", he says. 

'We need to be training and employing more expert botanists to do this important specialist work to protect Australia', Dr Hosking says.

"It is also vitally important that researchers collect and preserve specimens in herbaria so that identification can be confirmed at other times and from other sources. And for invasive species the sooner the correct identification is made the better," he says.

More information from:
Dr John Hosking, Weeds CRC, 02 6763 1129, 02 6765 5990 (a.h.)

Peter Martin, Weeds CRC, 08 8303 6693, 0429 830 366

Images of Siam weed available from Rita at rita.reitano at adelaide.edu.au

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