Protocol for initial weed risk assessment of plant species in NSW

Step 1 – Correct identity of the species determined

Correct determination of the plant species is critical before any assessment can be made. Determinations of suspect plant species are best made by sending pressed plant specimens to the NSW Early Detection Botanist. Submission of specimens is important even if the identity of the plant is thought to be certain and/or to keep records in herbaria up-to-date. The correct identification of weed specimens is an important part of the NSW New Weed Incursion Plan.

Step 1

Proceed to Step 2 when species identity is known

Step 2 – Is the species weedy in the world?

The most comprehensive reference list available to determine if a plant species is weedy somewhere in the world is the Global Compendium of Weeds (HEAR 2007). Although less comprehensive, one other significant reference is ISSG (2009).

It may be useful to use a search engine, for example Google^TM to determine if information on the weedy nature of a species is available online. A search engine may highlight information on alternate species names, or where species have recently been determined as weedy.

Plants that are weedy in one part of the world generally become weedy in other areas they are introduced into (Groves et al. 2001). Also note plants that are known to be invasive in their native range.

Step 2

If Yes, proceed to Step 3.
If No, proceed to Watch list.

Step 3 – Has the species naturalised in Australia?

A naturalised plant can be defined as one that reproduces consistently over a number of generations without direct human intervention (and often in spite of it) (Richardson et al. 2000, and see definitions overleaf ). Invasive plant species or weeds are often a smaller subset of the naturalised plants in a region.

One of the more comprehensive references to determine the naturalisation status of plants in Australia is AVH (2009). Another reference is Hosking et al. (in prep.). There are a number of books and online databases that may provide information however.

It is important to note that a native species found outside its native range and consistent with the definition above is also considered to have naturalised in this new area.

Step 3

If Yes, proceed to Step 4.
If No, proceed to Watch list.

Step 4 – Has the species naturalised in NSW, or in similar ecosystems in Australia?

One of the more comprehensive references to determine the naturalisation status of plants in NSW or in similar ecosystems in Australia is BGT (2009). Another reference is Hosking et al. (in prep.). There are a number of books and online databases that may provide further information.

It is important to note that a native plant species found outside its native range is considered naturalised if it reproduces for a number of generations in the introduced range. For example, Cootamundra wattle (Acacia baileyana) has naturalised outside its native range in many areas of NSW.

It is also important to consider species that are in commercial trade that may not have naturalised in NSW but have naturalised in similar ecosystems.

Climatic prediction maps can be determined using programs such as CLIMEX (Sutherst et al. 2007) or CLIMATCH (Crombie et al. 2008).

All species proceeding to Step 5 are subjected to assessment using the NSW WRM system. The relative priority for assessment is determined using the following steps.

Step 4

If Yes, proceed to Step 5.
If No, proceed to Watch list.

Step 5 – Is the species a known weed in at least one ecosystem in NSW, or similar ecosystems in Australia?

All naturalised plants do not become weeds (see definitions).

Only those plants that have adverse effects on primary production, environmental and/or societal values are considered weedy.

A plant species is more likely to be problematic if it is known to be a weed in at least one ecosystem or land use that occurs in NSW, or a similar ecosystem or land use in another area.

Some natural ecosystems that occur in NSW are listed below. For the purposes of this question, we consider primary production systems and areas used by humans (for example residential, service and utility areas) as land uses.

Some natural ecosystems in NSW include:

tropical rainforest (e.g. far north coast NSW);
subtropical rainforest (e.g. north Coast NSW);
temperate forest (e.g. coastal NSW);
temperate woodland (e.g. coastal and inland NSW);
heathland (e.g. coastal NSW);
grassland (e.g. generally inland NSW);
sub-alpine (e.g. highlands of NSW);
arid (e.g. generally far western NSW);
riparian (e.g. coastal to western NSW);
freshwater (e.g. coastal to western NSW); and
maritime, estuarine or saline (e.g. salt water environments in coastal and inland NSW).

We use the term ecosystem as a partial proxy for how well suited a plant is to grow in NSW. Suitability for plant growth will be impacted by many factors including climate, soils and landuse.

Species placed on Watch List

If the species does not satisfy all of the conditions identified at Steps 2 – 4, it is placed on the Watch List. This Watch List will be maintained by the NSW DPI. The List will be reviewed periodically by a group of relevant experts. This review will determine if new information has become available that changes the initial assessment. A revised assessment may involve assessment using the initial WRA protocol, and the NSW WRM system.

The review order will generally depend on the date the species was added to Watch List, starting with the earliest unreviewed species added.

Various references can be used to determine answers to this question including BGT (2009).

Step 5

If Yes, proceed to Step 6.
If No, species is allocated as Low priority for assessment using the NSW WRM system.

Low priority for assessment

Assessment of all low priority species will occur within 6 months of completion of an initial/revised Weed Risk Assessment (as above) and will use the NSW WRM system.

The only exceptions to this will be species that have any of the following growth forms or characteristics, that is:

aquatic;
grasses;
nitrogen fixing;
vines;
poisonous; and/or
cultivated in large numbers, or are soon to be cultivated in large numbers.

Each of these characteristics increase the risk a plant species poses to NSW.

These species will be treated as medium priority assessment species (see below).

Step 6 – Does the species have known impacts in NSW or similar ecosystems to NSW?

In general, the larger the size of the current or likely impacts a weed has, the more significant the weed will be. Potential impacts of a weed may include the following:

reductions in the establishment of desirable plants or animals;
reductions in the yield or amount of desirable plants or animals;
reduction in the quality of products, diversity or services available (this may include damage to the physical infrastructure of humans);
reduction in the physical movement of people, animals, vehicles, machinery and/or water;
negative impacts on the health of humans and/or animals; and/or
negative effects on environmental health, for example fauna, food and shelter, fire regime, soil nutrient levels, soil salinity, soil acidity, soil stability, the soil water table, or water quality.

This question applies to both NSW, or similar ecosystems to NSW.

Various references can be used to determine answers to this question.

Medium priority for assessment

Assessment of all medium priority species will occur within 3 months of the completion of an initial/revised Weed Risk Assessment (as above) and will use the NSW WRM system.

Step 6

If Yes, proceed to Step 7.
If No, species is allocated as Medium priority for assessment using the NSW WRM system.

Step 7 – High priority for assessment by NSW Weed Risk Management system

If the species satisfies all the conditions identified at Steps 1–6 it will be placed on the list for high priority assessment using the NSW WRM system.

High priority for assessment

Assessment of all high priority species will occur within 6 weeks of the completion of an initial/revised Weed Risk Assessment (as above) and will use the NSW WRM system.

Step 7

Definitions

The following terms are defined as follows

Introduced plant – any plant species that is not native to Australia.

Native plant species – any plant species that occurred before European settlement in Australia. This includes trees (saplings, tall shrubs and scrub), understorey plants, groundcover plants (any type of herbaceous vegetation) and plants occurring in a wetland (as adapted from the Native Vegetation Act 1993).

Mangroves and seagrass species (angiosperms belonging to Kingdom Plantae) are also included (as adapted from the Fisheries Management Act 1994). For the purposes of this document, a 'native plant species' also includes other marine vegetation under the Fisheries Management Act 1994 within the Kingdoms Chromista (brown algae/seaweeds) and Protista (red algae/seaweeds), despite these species not being part of the Plantae.

The above definition of a native plant species is further qualified in that these species need to be taxa that have originated in a given area without human involvement or that have arrived there without intentional or unintentional intervention of humans from an area in which they are native (Pysek et al. 2004).

Naturalised plant – a plant species (whether introduced or native) that reproduces consistently and sustains populations over many lifecycles without direct intervention by humans (or in spite of human intervention) (Richardson et al. 2000).

Taxa (plural) and Taxon (singular) – a taxonomic grouping of plants. For example, a Family, Genus (plural genera), Species, Subspecies, Variety, Form, Cultivar or Species aggregate are all examples of taxa.

Weed – a plant species (whether introduced or native) that grows in sites where it is not wanted and which usually has detectable negative economic, environmental or societal effects (adapted from Richardson et al. 2000).

References

AVH, Australia's Virtual Herbarium (2009). Map Search Interface.

BGT, Botanic Gardens Trust (2009). PlantNET.

Google (2009). Google^TM Australia.

Groves, R. H., Panetta, F. D. and Virtue, J. G. (eds.) (2001). Weed Risk Assessment. CSIRO Publishing. 244 pp.

HEAR, Hawaiian Ecosystems at Risk (2007). Global Compendium of Weeds.

Hosking, J., Sainty, G., Jacobs, S. and Dellow, J. (in prep.). The Australian WEEDbook.

ISSG, Invasive Species Specialist Group (2009). Global Invasive Systems Database.

Johnson, S. B. (2009). The New South Wales Weed Risk Management System. New South Wales Department of Primary Industries, Orange. 127 pp. Also available at URL:

Pysek, P., Richardson, D. M., Rejmanek, M., Webster, G. L., Williamson, M. and Kirschner, J. (2004). Alien plants in checklists and floras: towards better communication between taxonomists and ecologists. Taxon, 53, 131-143.

Richardson, D. M., Pysek, P., Rejmanek, M., Barbour, M. G., Panetta, F. D. and West, C. J. (2000). Naturalization and invasion of alien plants: concepts and definitions. Diversity and Distributions, 6, 93-107.

Sutherst, R. W., Maywald, G. F. and Kriticos, D. J. (2007). CLIMEX Version 3:User guide. Hearne Scientific Software Pty Ltd.

Authors

This protocol was developed by Stephen Johnson, Scott Charlton, John Hosking, Andrew Petroeschevsky and Bruce Auld.