Invasive Species Council - Weed Risk Assessment

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- weed risk assessment
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In 1997 Australia introduced Weed Risk Assessment (WRA), a process for assessing the weed risk posed by new plants.

In the main article below, ISC Councillor Tim Low, argues that Weed Risk Assessment is not operating as it should and needs an urgent overhaul. The system is so flawed it raises serious questions about the competence and commitment of our quarantine service.

Many known or potential weeds, including whole genera, appear on the 'permitted list' and can thus be imported legally into Australia, irrespective of their status as weeds, without requiring any weed risk assessment whatever.
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Gaping Holes in the Weed Screen
by Tim Low
reprinted from Feral Herald, volume 1 issue 3, April 2003

In 1997 Australia introduced Weed Risk Assessment (WRA), a process for assessing the weed risk posed by new plants. WRA is a series of 49 questions asked of any new plant proposed for import. Questions include is it toxic, is it aquatic, is it a grass? If a plant scores 'yes' too many times it is forbidden entry. WRA is applied to any new plants that nurseries, pasture scientists or anyone else wants to bring into the country. Because it is more stringent than the systems most countries use, WRA has won much praise here and overseas.

But WRA is not operating as it should. Hundreds of weeds may be imported legally into Australia without any assessment whatever. The system is so flawed it raises serious questions about the competence and commitment of our quarantine service.

WRA is applied only to new plants, not to species already in Australia. Most foreign plants already in the country (cultivated plants and weeds) appear either on a permitted (white) list or a prohibited (black) list. Regrettably, these lists are not available for public scrutiny. However, anyone can find out if they may import a specific plant merely by visiting the appropriate AQIS web page and typing the plant's name into their import conditions (ICON) database. The database lists the import conditions for more than 18,000 foreign plant, animal, mineral and human commodities.

One anomaly of the system is that it does not prohibit weeds already in Australia, except under limited circumstances. Anyone may, for example, import the seeds of stinging nettles (Urtica urens), paspalum (Paspalum dilatatum), chickweed (Stellaria media), cobbler's pegs (Bidens pilosa) and blackberry nightshade (Solanum nigrum), not to mention madeira vine (Anredera cordifolia) and ivy (all Hedera species), provided the seeds are clean of impurities. If, for example, you type Urtica urens into the ICON website you are told:

"Non-commercial consignments of seed of this species may be permitted entry into Australia subject to inspection on arrival. Seed must be free from soil, live insects, plant material (e.g. fruit pulp, leaf or stem material, etc), contamination with prohibited seeds and packed in new containers that are clearly labelled with the botanical name."

This anomaly exists because Australia is a signatory to the World Trade Organization Agreement on the Application of Sanitary and Phytosanitary Standards (the 'SPS Agreement'). Under this agreement weeds already in a country may be banned only if their distribution is limited and they are subject to an 'official control program', or if an importer wants to introduce a new strain that differs genetically such that it poses a greater weed risk than existing strains. Unfortunately, the Australian quarantine service seldom uses even these limited provisions to ban existing weeds.
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"Anyone may, for example, import the seeds of stinging nettles"
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Secondly, and even more seriously, many thousands of foreign plants not yet found in Australia - including serious weeds - can bypass weed risk assessment because they have found their way onto the permitted list.

In the case of grasses (one of the most invasive of all plant groups) the ICON database shows that many genera are permitted entry without WRA. For example, for saltgrass (Distichlis spicata), the ICON database shows that one may bring in not only Distichlis spicata but every related grass in genus Distichlis, provided the proper protocols, such as ensuring the seeds are free of contaminants, are followed.

The same is true of many other weedy grass genera. Genus Brachiaria contains about a hundred different grasses, mostly native to Africa, and including several weeds in Australia such as para grass (Brachiaria mutica), a major invader of tropical wetlands. But according to the ICON database, only three species of Brachiaria are prohibited entry (and para grass is not one of them). All the rest may be legally imported, provided the seed is clean of impurities, without WRA, even if they are major weeds overseas.

This loophole has arisen for the following reasons. In the days before WRA was introduced, pasture researchers imported seeds of various grasses for research. At that time no-one considered whether the grasses would become weeds; the only concern was that imported seed might harbour impurities, such as fungal infections, insects and certain weed seeds. So AQIS devised a set of protocols, outlining the treatments and standards to be met by anyone importing the seeds. To save time and trouble for AQIS and their clients, AQIS declared that the protocols developed for one species of Distichlis or Brachiaria would apply to other plants in that genus. Because these protocols existed, these genera were placed on the permitted list. The same process was applied to garden plants. Once a protocol was developed for one species, the whole genus usually ended up on the white list.

So how many genera does the white (permitted) list contain? Rod Randall of the Western Australian Department of Agriculture says there are more than 3,000 - a number so vast it makes a nonsense of WRA. Included are most genera of garden plants and crop plants in Australia, many of which include weedy species, for example Brassica and Portulaca.
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"Weed Risk Assessment needs an urgent overhaul."
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When Weed Risk Assessment was introduced in 1997 the federal government realised these genera required attention. A consultant was engaged to go through the white list and recommend species and genera for removal. But so far, almost no changes to the list have been made.

Another problem, says Randall, is that many plants in the ICON database are misspelt, or listed under antiquated names. The prickly pear genus, for example, appears as Upuntia as well as Opuntia.

Another weakness is that prohibited plants can gain entry when an importer lists them under outdated names. Mexican feather grass (Nasella tenuissima), a weedy relative of serrated tussock (N. trichotoma) - one of our 20 worst weeds - was allowed in because the importer unwittingly used an old name: Stipa tenuissima. Stipa is a permitted genus, Nasella is not.

Weed Risk Assessment needs an urgent overhaul. Whole groups of plants, including serious weeds, need not go through WRA for reasons that have nothing to do with their weed status. WRA was never meant to operate like this.

The ISC has written to the Chief of Biosecurity Australia, Mary Harwood, raising questions about the operation of WRA. See item at right.

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Worth the Risk?
reprinted from Feral Herald, volume 1 issue 4, July 2003

The federal government is showing a growing commitment to addressing future weed problems. But very little progress - if any - has been made in resolving the conflicts of interest that arise when a plant that is useful to one sector of society is a weed elsewhere. The three main problem areas are garden, pasture, and now salinity plants. It is thus of interest to see a new paper that questions current policies: Worth the Risk? Introduction of legumes can cause more harm than good.

It was put together by the CSIRO's Quentin Paynter and nine other government weed experts. Most new legumes are deliberately introduced as pasture plants by government agencies, so this article represents government pleading to government. The authors note that five of the 20 Australian weeds declared as Weeds of National Significance were deliberately introduced legumes.

Here are some quotes:
'With the benefit of hindsight, continued promotion of woody legumes should be seriously questioned.'

'Currently, it seems environmentally and economically prudent to avoid introducing any new plant material, even if this means excluding some beneficial species, until our predictive ability improves.'

'It is also environmentally and economically prudent to reassess the risks and benefits of continued planting of species such as [tagasaste] Cytisus proliferus and [leucaena] Leucaena leucocephala, which were introduced before the WRA was set up.'

'For most Australian noxious legumes to be the result of deliberate introductions for their perceived beneficial properties ...there must have been inadequate consideration of their potentially detrimental attributes, prior to introduction'

'Novel introductions should be discouraged if there are native species that could perform the tasks for which the exotic species is being imported.'

'We believe the creation of national weed problems due to the desire for novelty in the nursery industry is unacceptable.'

The article was published in Australian Systematic Botany: 16: 81-8. Copies can be obtained from Quentin Paynter at the CSIRO.