NSW WRM system - Further information

Calculation of overall uncertainty score

The overall uncertainty score is calculated by adding all the section uncertainty scores and then dividing this by the number of sections (six).

Alternatively, to calculate manually, record the percentage uncertainty scores from the Weed risk uncertainty score and Feasibility of coordinated control uncertainty score below and then divide by six.

Section Adjusted uncertainty score (Percentage uncertainty)
Potential distribution  
Control costs  
Current Distribution  

=(sum of adjusted uncertainty scores above)/6 (round to nearest whole number)

The following levels of overall uncertainty need to be considered before submitting assessments. Assessments submitted with levels of overall uncertainty exceeding 15% will generally be returned to the assessor/s for further research.

Overall uncertainty level Response needed
<15% Submit assessment (ensure all information sources have been attached)
15-30% Revisit existing literature and source new literature before submitting assessment (contact NSW DPI staff for other possible information sources)
>30% Do not submit assessment (contact NSW DPI regional staff for help in locating information)

Positive impacts

Potential conflicts of interest exist when plants are considered as weeds in one situation but of economic use in another situation. Such conflicts of interest need careful consideration including consultation between all stakeholders.

This section looks at any other positive impacts a weedy plant may have. Note that some positive impacts on environmental health have already been considered in Question 6 in the Impacts section. These should be noted here as text with any references included. If needed, NSW DPI will make a separate assessment of the positive benefits of a species. That separate assessment will include appropriate consultation.

Conflicts of interest may arise when plants used for human or livestock food, pollen and nectar sources, for timber, herbal medicine, gardening and landscaping, as aquatic/aquaria species, for shelter and amenity, for soil conservation and revegetation, or for turf, escape cultivation and become weedy. Examples of potential conflicts of interest include:

  • Human food species which may also escape and threaten various environmental areas, for example, Coffee (Coffea arabica), European olive (Olea europaea subsp. europaea), Blackberry (Rubus fruticosus species aggregate and other Rubus species), Passionfruit (Passiflora edulis), Asparagus (Asparagus officinalis), and a failed Nashi pear plantation rootstock species (Pyrus pashia). This also includes native bush foods.
  • Livestock forage species such as African lovegrass (Eragrostis curvula), Kikuyu (Pennisetum clandestinum), Leucaena (Leucaena leucocephala) and White clover (Trifolium repens), invading agricultural and environmental areas. The added advantage of the last two species, and other legumes, is that they fix nitrogen in the soil.
  • Potential pollen and nectar sources for bees such as Paterson's curse (Echium plantagineum).
  • Timber species such as Pines (Pinus species), Paulownia (Paulownia tomentosa) and Camphor laurel (Cinnamomum camphora), all of which are often planted for commercial and amenity purposes, invading environmental areas. Timber species can be used for a wide range of purposes including building materials, the pulp can be used for the production of paper and other products, and for as firewood and charcoal. A range of products can be extracted from bark including tannins (for leather production) and resins, flocculants, thinners, adhesives and dust suppressants.
  • Herbal species such as St. John's wort (Hypericum perforatum), Horsetail (Equisetum species) and newer species such as Cape aloe (Aloe ferox) that are all known to be significant weeds in various situations. This may include species with potential medicinal value.
  • Ornamental (gardening and landscaping) species including those sold in the past, such as Lantana (Lantana species and hybrids), Bridal creeper (Asparagus asparagoides), African olive (Olea europaea subsp. cuspidata) and Fountain grass (Pennisetum setaceum), or newer species such as Mexican feather grass (Nassella tenuissima), among many other species. Each of these species have various environmental or agricultural impacts once they escape.
  • Aquatic (pond) and aquarium species such as Salvinia (Salvinia molesta), Water hyacinth (Eichhornia crassipes) and Water lettuce (Pistia stratiotes) which are only occasionally now sold, and others such as Leafy elodea (Egeria densa) and East Indian Hygrophila (Hygrophila polysperma) which are spreading and seriously impacting aquatic areas. There are likely to be a range of other serious weeds in trade such as Yellow burrhead (Limnocharis flava) which has naturalised in Queensland, or others which have not yet naturalised but are likely to threaten the environment in future.
  • Common shelter and amenity species such as Willows (Salix species) and Athel pine (Tamarix aphylla), or the less common Box elder (Acer negundo), which have a large number of positive and negative benefits.
  • Species used for soil conservation and revegetation purposes. The species Lippia (Phyla canescens) and Willows (Salix species) were once used for these purposes whereas Buffel grass (Cenchrus ciliaris) is now used in many western areas and the native shrub Golden wreath wattle (Acacia saligna) is used for salinity remediation purposes.
  • Species used as turf such as the grass Kikuyu (Pennisetum clandestinum) and the broad-leaf Lippia (Phyla canescens) which have significant environmental impacts once they escape.
  • Conflict species of the future may include those:
    • promoted for alternate fuel production such as Jatropha/Physic nut (Jatropha curcas) and Giant reed (Arundo donax)
    • that have potential to sequester and store carbon, a commodity which may be potentially traded in future
    • that are used in waste water treatment
    • that are used as bio-indicators of heavy metals, or for remediation of sites affected by these metals
    • that are used as fertiliser, for example the free floating Azolla (Azolla species).

There are likely to be a large number of other examples that have not been mentioned under each of these categories, and perhaps other categories that have not been mentioned above.

Under the provisions of the Noxious Weeds Act 1993, all proposals for declaration of a plant as a noxious weed are subject to full public consultation. Any person who feels that there are positive benefits of the plant will probably raise objections to the declaration. They have the legal right to do this and their arguments are likely to be valid. It is important that any of these stakeholders and the plants positive benefits are fully considered in the WRM system and not dismissed out of hand.

Are there any other positive impacts the species may have?
Positive impactSource

List any stakeholders consulted in regards to this question below and the outcomes of these discussions.

Stakeholders consulted Outcomes

Further comments

This section allows the assessor/s the opportunity to offer further comments they feel could help support the assessment. Assessors are invited to provide comments in the assessment form and to attach further comments and documents if necessary. It is not compulsory to offer comments nor is it compulsory to offer sources of information in this section.

Assessors are asked to answer all questions before offering comments. This section therefore provides the opportunity for assessors to add information on areas that they feel have not been covered by the questions. This information may be of an economic, environmental or social nature and may include positive or negative aspects. For example comments may be offered on:

  • Human or animal welfare issues, for example primary producers who are affected by certain weed infestations may struggle with depression or despair. In this case do not consider any physical health impacts of weeds on animals or people as these have already been covered in the Impacts section in Question 5.
  • Known social issues affecting weed management, that is issues not covered in the Control costs section in Question 4 (landholder/volunteer financial and technical capacity). Relevant social issues could include past adoption of desirable or similar management practices, landholder management goals (for example commercial production or lifestyle), the strength of local networks and community groups to encourage and support management, peer pressure which may either encourage or hinder management, and trust and cooperation within the community.
  • Known socio-political issues affecting weed management, for example community opposition to certain management practices, non-cooperation by other organisations and social/administrative/political constraints on the acceptability of a weed and/or management practices associated with it.
  • Changes in practice in primary production enterprises that may occur, for example a change in cropping rotations as a result of weed invasion. This may result in a change in land values.
  • The impact of control measures on quality assurance programs or on organic farming, for example if an area is treated with certain herbicides then properties may not be able participate in quality assurance programs for certain products or be able to maintain organic production status.
  • The impact of control measures for one species resulting in invasion of another weedy species. For example, Glory lily (Gloriosa superba) often invades areas cleared of Bitou bush (Chrysanthemoides monilifera subsp. rotundata).
  • The genetic pollution of native remnant populations of a plant after different populations of the same plant are introduced and cross-breed. For example, considerable genetic contamination between the subspecies of both Golden wreath wattle (Acacia saligna) and York gum (Eucalyptus loxophleba) has resulted in southern Western Australia when populations of both species were introduced for salinity remediation works near remnant populations (Byrne et al. 2008). Hybridisation across species within the same plant family, although comparatively rare, may also result after the introduction of a new species. For example, Cootamundra wattle (Acacia baileyana) will hybridise with a number of other wattle (Acacia species) including Green wattle (A. decurrens) and Silver wattle (A. dealbata).
  • Whether the weed acts as a host of pathogens that cause plant diseases.
  • Any iconic value that a species, or a site with the species, may represent, for example, Cootamundra wattle (Acacia baileyana) is a well known native species in south western NSW, but is weedy outside of this range.

Positive impacts of the species should be noted in the Positive impacts section.

If needed, NSW DPI will make a separate assessment of the comments offered in this section. This assessment may include appropriate consultation.


The NSW WRM system has drawn on information contained in a number of sources, in particular the National Post-Border Weed Risk Management Protocols (Virtue et al. 2006). Acknowledgement is made of all contributors to that document.

The wording used in this document has been drawn extensively from the South Australian Weed Risk Management Guide (Virtue 2004) developed by the Department of Water, Land and Biodiversity Conservation. Particular acknowledgement is made of Dr John Virtue.

Useful additions to the wording have also been drawn from the Northern Territory Weed Risk Management system which is a joint Charles Darwin University and Northern Territory Government initiative. Particular acknowledgement of Dr Samantha Setterfield and Ms Natalie Rossiter of Charles Darwin University and Dr Keith Ferdinands of the Northern Territory Department of Natural Department of Natural Resources, Environment, The Arts and Sport is made.

Acknowledgment is made of the assistance, suggestions and comments received from NSW DPI and NSW local government staff.

References cited in text

The following is a list of all references cited in the preceding document. Sources of other information follow in a separate section.

AG BRS, Australian Government Bureau of Rural Sciences (2009). Land use mapping for Australia. Online at http://adl.brs.gov.au/mapserv/landuse/ Access date 12 August 2009.

AG DAFF, Australian Government Department of Agriculture, Fisheries and Forestry (2009). National Agricultural Monitoring System. Online at www.nams.gov.au  Access date 12 August 2009.

AG DEWHA, Australian Government Department of Environment, Water, Heritage and the Arts (2009). Australian Natural Resource Atlas. Online at www.anra.gov.au Access date 12 August 2009.

Byrne, M., Millar, M.A. and Sampson, J. (2008). Potential for genetic contamination of remnant native populations from planted stands of woody perennials in fragmented agricultural landscapes. In, 2nd International Salinity Forum. Salinity, water and society - global issues, local action. Adelaide.

Champion, P. D. and Clayton, J. S. (2001). A weed risk assessment model for aquatic plants in New Zealand. Chp. 16, In, Weed Risk Assessment. Eds. R. H. Groves, F. D. Panetta and J. G. Virtue. CSIRO Publishing, Collingwood, Victoria. pp. 194-202.

Coutts-Smith, A. J. and Downey, P. O. (2006). Impact of weeds on threatened biodiversity in New South Wales. Technical series no.11. Cooperative Research Centre for Australian Weed Management, Adelaide. 98 pp.

Crombie, J., Brown, L., Lizzio, J. and Hood, G. (2008). Climatch user manual. Australian Government, Bureau of Rural Sciences. Online at www.brs.gov.au/climatch/  Access date 12 August 2009.

Downey, P. O., Williams, M. C., Whiffen, L. K., Turner, P. J., Burley, A. L. and Hamilton, M. A. (2009). Weeds and biodiversity conservation: A review of managing weeds under the New South Wales Threatened Species Conservation Act 1995. Ecological Management and Restoration, 10 S1, S53-S58.

Groves, R. H. and Panetta, F. D. (2002). Some general principles for weed eradication programs. Proceedings of the 13th Australian Weeds Conference, eds. H. Spafford-Jacob, J. Dodd and J. H. Moore. Plant Protection Society of Western Australia, Perth. pp. 307-310.

Groves, R. H., Shepherd R. C. H. and Richardson, R. G. (editors) (1995). The Biology of Australian Weeds. Volume 1. Publishers R. G. and F. J. Richardson, Meredith, Victoria. 314 pp.

Hayes, K. R., Regan, H. M. and Burgman, M. A. (2007). Introduction to the concepts and methods of uncertainty analysis. Chp. 7 In, Environmental risk assessment of genetically modified organisms. Volume 3. Methodologies for transgenic fish in developing countries. Eds. A. R. Kapuscinski, K. R. Hayes, S. Li and G. Dana. CAB International. pp. 188-208.

Johnson, S. B. and Charlton, S. A. (2009). Who is who in the weed management zoo? Sorting out the confusion around weed management in NSW. Proceedings of the 15th Biennial NSW weeds conference, Narrabri. New South Wales Department of Primary Industries, Orange.

McNaught, I., Thackeray, R., Brown, L. and Parsons, M. (2006). A field manual for surveying and mapping nationally significant weeds. Australian Government, Bureau of Rural Sciences Canberra. 52 pp.

NSWG, New South Wales Government (2009). New South Wales Natural Resource Atlas. Online at www.nratlas.nsw.gov.au Access date 12 August 2009.

NTG, Northern Territory Government (2009). Northern Territory Weed Risk Management system. http://www.nt.gov.au/nreta/natres/weeds/risk/index.html

Panetta, F. D., Groves, R. H. and Shepherd, R. C. H. (editors) (1998). The Biology of Australian Weeds. Volume 2. Publishers R. G. and F. J. Richardson, Meredith, Victoria. 327 pp.

Panetta, F. D. (editor) (2009). The Biology of Australian Weeds. Volume 3. Publishers R. G. and F. J. Richardson, Meredith, Victoria. 326 pp.

Panetta, F. D. and Timmins, S. M. (2004). Evaluating the feasibility of eradication for terrestrial weed incursions. Plant Protection Quarterly, 19, 5-11.

Randall, R. P. (2000). 'Which are my worst weeds?' A simple ranking system for prioritizing weeds. Plant Protection Quarterly, 15, 109-115.

Virtue, J. G. (2004). Proclaimed plants. South Australian Department of Water, Land and Biodiversity Conservation. Online at: www.dwlbc.sa.gov.au/biodiversity/apc/policy.html

Virtue, J., Cunningham, D., Hanson, C., Hosking, J., Miller, I., Panetta, D., Pheloung, P., Randall, R., Timmins, S., Walton, C., Weiss, J. and Williams, P. (2006). National PostBorder Weed Risk Management Protocol. Standards Australia, Standards New Zealand and the Cooperative Research Centre for Australian Weed Management.  76 pp.

Information sources

The following list contains a large number of references that may be suitable information sources. The references contained are listed alphabetically by author and include published reference books, general plant and weed control guides, Flora's (botanical plant guides), general industry publications and internet sources. Further information sources may be found in any given reference. This is not an exhaustive list.

APNI, Australian Plant Names Index (2009). Australian Plant name Index (APNI). Online at http://www.anbg.gov.au/cgi-bin/apni

APVMA, Australian Pesticides and Veterinary Medicines Authority (2009). PUBCRIS registered product search engine, and permits search. Online at http://services.apvma.gov.au/PubcrisWebClient/welcome.do  and www.apvma.gov.au/permits/permits.shtml respectively.

Auld, B. A. and Medd, R. W. (1987). Weeds. An illustrated botanical guide to the weeds of Australia. Inkata Press, Melbourne. 255 pp.

AVH, Australia's Virtual Herbarium (2009). Online at www.chah.gov.au/avh/ Bing (2009). Online at www.bing.com/

Blood, K. (2001). Environmental weeds. A field guide for south east Australia. C. H. Jerram Science Publishers, Mt Waverly. 228 pp.

Coutts-Smith, A. J. and Downey, P. O. (2006). Impact of weeds on threatened biodiversity in New South Wales. Technical series no.11. Cooperative Research Centre for Australian Weed Management, Adelaide. 98 pp.

CRC Weeds, Cooperative Research Centre for Australian Weed Management (2008). Online at http://www.weedscrc.org.au/

Csurhes, S. and Edwards, R. (1998). Potential environmental weeds in Australia. Candidate species for preventative control. Queensland Department of Primary Industries, Brisbane. 202 pp.

Cunningham, G. M., Mulham, W. E., Milthorpe P. L. and Leigh J. H. (1992). Plants of western New South Wales. Inkata Press, Melbourne. 766 pp.

DEWR, Department of the Environment, Water Heritage and the Arts (2009). Weeds in Australia. Online at http://www.weeds.gov.au/index.html

Ensbey, R. and Johnson, A. (2007). Noxious and environmental weed control handbook, 3rd edition. New South Wales Department of Primary Industries, Orange. 80 pp.

Future Farm Industries Cooperative Research Centre (2009). The Environmental Weed Risk Protocol. Online at http://www.futurefarmcrc.com.au/weed_risks.html

GISD, Global Invasive Species Database (2009). Online at http://www.issg.org/database/welcome/

Google Australia (2009). Online at http://www.google.com.au/

Groves, R. H., Shepherd R. C. H. and Richardson, R. G. (editors) (1995). The Biology of Australian Weeds. Volume 1. Publishers R. G. and F. J. Richardson, Meredith, Victoria. 314 pp.

Harden, G. J. (ed.) (1990). Flora of New South Wales, Volume 1. University of NSW Press, Kensington. 601 pp.

Harden, G. J. (ed.) (1991). Flora of New South Wales, Volume 2. University of NSW Press, Kensington. 574 pp.

Harden, G. J. (ed.) (1992). Flora of New South Wales, Volume 3. University of NSW Press, Kensington. 717 pp.

Harden, G. J. (ed.) (1993). Flora of New South Wales, Volume 4. University of NSW Press, Kensington. 775 pp.

HEAR, Hawaiian Ecosystems at Risk (2009). Global compendium of weeds. Online at www.hear.org/gcw

Holm, L., Doll, J., Holm, E., Pancho, J. and Herberger, J. (1997). World weeds. Natural histories and distribution. John Wiley and Sons, New York. 1129 pp.

Kealey, L. M. and Clampett, W. S. (2007). Production of quality rice in south eastern Australia. Rural Industries Research and Development Corporation, Canberra. (Chapter 9 covers weed management and identification).

Kleinschmidt, H. E. and Johnson, R. W. (1977). Weeds of Queensland.  Australian Government Publishing Service, Brisbane. 469 pp.

Johnson, S. B., Charles, G. W., Roberts, G. N. and Taylor, I. N. (eds.) (2002). WEEDpak. A guide for the integrated management of weeds in cotton. Australian Cotton Cooperative Research Centre, Narrabri. Online at www.cottoncrc.org.au/content/Industry/Publications/Weeds/WEEDpak.aspx

Moerkerk, M., Wurst, M. and Yeatman (no date). Weeds: The Ute Guide Southern Grain Belt Edition version 2. Primary Industries and Resources South Australia, Adelaide. 249 pp.

Muyt, A. (2001). Bush invaders of south-east Australia. R. G. and F. J. Richardson, Meredith, Victoria. 304 pp.

NSW DII, New South Wales Department of Industry and Investment (2009). Weeds. Online at www.dpi.nsw.gov.au/agriculture/pests-weeds/weeds (For links to Primefacts, Weed Alerts and Species reviews).

Panetta, F. D. (editor) (2009). The Biology of Australian Weeds. Volume 3. Publishers R. G. and F. J. Richardson, Meredith, Victoria. 326 pp.

Panetta, F. D., Groves, R. H. and Shepherd, R. C. H. (editors) (1998). The Biology of Australian Weeds. Volume 2. Publishers R. G. and F. J. Richardson, Meredith, Victoria. 327 pp.

Parsons, W. T. and Cuthbertson. E. G. (2001). Noxious weeds of Australia, 2nd edition. CSIRO publishing, Collingwood, Victoria. 698 pp.

PlantNET (2009). Flora Online module of PlantNET. Royal Botanic Gardens and Domain Trust, Sydney. Online at http://plantnet.rbgsyd.nsw.gov.au/search/simple.htm

Queensland Department of Primary Industries and Fisheries (2009). Pest risk assessments. Online at www.dpi.qld.gov.au/cps/rde/dpi/hs.xsl/4790_9161_ENA_HTML.htm

Sainty G. R. and Jacobs S. W. L. (2003). Waterplants in Australia, 4th edition. Sainty and Associates, Potts Point. 416 pp.

Shepherd, R. C. H., Richardson, R. G. and Richardson, F. J. (2001). Plants of Importance to Australia. A checklist. Publishers R. G. and F. J. Richardson, Meredith, Victoria, Australia. 358 pp.

Stanley, T. D. and Ross, E. M. (1986). Flora of South–Eastern Queensland, Volume 3. Queensland Department of Primary Industries, Brisbane. 532 pp.

Stanley, T. D. and Ross, E. M. (1995). Flora of South–Eastern Queensland, Volume 1. Queensland Department of Primary Industries, Brisbane. 545 pp.

Stanley, T. D. and Ross, E. M. (1995). Flora of South–Eastern Queensland, Volume 2. Queensland Department of Primary Industries, Brisbane. 622 pp.

Tasmania DPIPWE, Department of Primary Industries, Parks, Water and Environment. Weed Risk Assessment Scoresheets and Reports. Online at www.dpiw.tas.gov.au/inter.nsf/WebPages/SWEN-7S74GE?open

Turner, G. and McMahon, G. (1989). Weeds in Australian cane fields. Part A. A guide to identification of weeds. Special edition BSES bulletin. Bureau of Sugar Experiment Stations, Indooropilly. 84 pp.

VIC DPI, Victorian Department of Primary Industries (2009). Pest plants. Online at www.dpi.vic.gov.au/vro/weeds

Virtue, J. G. (2004). South Australian Weed Risk Management system, Weed Risk Assessment spreadsheet. South Australian Department of Water, Land and Biodiversity Conservation. www.dwlbc.sa.gov.au/biodiversity/apc/policy.html

Weeds Australia (2009). Online at www.weeds.org.au/

Wilson, B. J., Hawton, D. and Duff, A. A. (1995). Crop Weeds of Northern Australia. Queensland Department of Primary Industries, Brisbane. 160 pp.

Wood, P., Cahill, M., Marlow, G. and Douglas, N. (compilers) (2000). Weeds: The Ute Guide Northern Grain Belt Edition. Department of Primary Industries, Toowoomba. 190 pp