Reasons for the weed risk assessment system
All plants imported into Australia, regardless of end use, have the potential to become weeds in Australia. Having a system to screen new plant introductions for weed potential reduces the chances of new weeds entering Australia.
Since the 1800s new plant species have been introduced into Australia for a range of uses including agricultural production, horticulture and as ornamental plants. Over time a proportion of these species have escaped from domestic or agricultural cultivation and become weeds in Australia.
There are approximately 10,000 native plant species, and 26,000 introduced exotic species, currently in cultivation in Australia (Randall 2006). Of these introduced species, approximately 2,800 species have naturalised. Approximately 10% of naturalised species in Australia are now proclaimed as noxious weeds under state/territory legislation (WAD 2008).
Garden plant introductions are the primary source of new naturalised plants and weeds in Australia (Groves et al. 2005). Of the 2,800 introduced plant species now estimated to be established in Australia, 66% are escaped garden plant species (Groves et al. 2005). The economic cost of naturalised weed species to Australian agriculture is estimated to be over $4 billion annually (Sinden et al. 2004). The environmental cost is also high, with invasive species second only to land clearing as a cause of global biodiversity loss (DEWHA 2007). Additionally, weeds have non-monetary costs, such as health costs (for example, plants that cause asthma or skin irritations), amenity costs (for example, plants that choke waterways preventing passage) and aesthetic costs.
The direct cost of weed control is largely borne by governments and landowners (Martin 2008). Preventing the importation of potential new weed species may result in the reduction of future weed control expenditure.
Legislative controls
Originally, the Australian Quarantine and Inspection Service (AQIS) was responsible for assessing quarantine risks. Biosecurity Australia is now responsible for developing quarantine policies in Australia, in line with Australia's international rights and obligations and Commonwealth Government policies.
AQIS is the Commonwealth agency which implements Australia’s quarantine policy. Under the Quarantine Act 1908, AQIS regulates the importation of all types of plant material, including propagable material, into Australia. Schedule 5 of the Quarantine Proclamation 1998 lists permitted seeds. These acts do not differentiate between plant end usages.
The Department of Environment, Water, Heritage and the Arts (DEWHA) is the agency with administrative responsibility to restrict plant imports under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). During the development of the Weed Risk Assessment system it was determined to adequately assessed the potential environmental risk of plant imports. The Live Import List established under the EPBC Act is taken to include any plant species allowed to be imported under Schedule 5 of the Quarantine Proclamation 1998 as administered by AQIS.
Australia’s international obligations
In developing quarantine policies for the importation of plants and plant products, Biosecurity Australia complies with Australia’s international rights and obligations. These rights and obligations result from Australia being a signatory to both the World Trade Organisation, under the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS agreement), and the International Plant Protection Convention.
References
DEWHA (2007) Why are weeds a problem? Weeds in Australia website. Department of Environment, Water, Heritage and the Arts (DEWHA). Online at: http://www.weeds.gov.au/weeds/why/index.html.
Groves RH, Boden R, Lonsdale WM (2005) Jumping the Garden Fence: Invasive garden plants in Australia and their environmental and agricultural impacts. CSIRO report prepared for WWF-Australia. WWF-Australia, Sydney.
Martin P (2008) Cross pollination or cross-contamination? Directions for informing the management of invasives with marker-economy concepts. Proceedings of the 16th Australian Weeds Conference, 18–22 May 2008, Cairns Convention Centre 6–13.
Randall RP (2006) The Australian exotic species database, a CRC for Australian Weed Management project. Proceedings of the 15th Australian Weeds Conference, Adelaide South Australia 24–28 September 2006.
Sinden J, Jones R, Hester S, Odom D, Kalisch C, James R, Cacho O (2004) The economic impact of weeds in Australia, CRC for Australian Weed Management, Adelaide, Technical Series No 8, Adelaide. pp 55.
WAD (2008) Noxious weeds list. Weeds Australia Database, Australian Weeds Committee. Online at: http://www.weeds.org.au/noxious.htm.