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Appendix 2
Workshop exercises and discussion


Introduction to the exercises

Participants at the workshop entitled "Invasive alien species and the International Plant Protection Convention", which was held in Braunschweig, Germany, 22 - 26 September 2003, took part in exercises designed to illustrate aspects of the management of invasive alien species using the framework and body of knowledge developed under the International Plant Protection Convention.

The first workshop exercise looked at how to review a legal regime for control of invasive alien species. It employed the example of an imaginary group of neighbouring African countries confronting a new pest situation. Sample results from the groups are presented below.

The second exercise studied a pest risk analysis (PRA). The pest risk analysis used a PRA questionnaire designed for the exercise and data drawn from practical experience, namely EPPO data sheets on the quarantine pest Anoplophora glabripennis. An explanation of the exercise and sample results are reported in this appendix.

Exercise 3 investigated the method for a weed risk assessment (WRA). Documentation for the weed risk assessment included a description of the WRA system, guidelines for answering WRA questions and the WRA risk assessment question sheet and scoring. These documents are also included in this appendix.

On the last day, a discussion group considered the way forward from the workshop. The recommendations arising from this discussion are reported immediately preceding the appendices.

Exercise 1: Methodology for review of a legal regime for the phytosanitary control of invasive alien species

The scenario

Bokona is a landlocked West African state that shares boundaries with Bonga to the north, Tiga to the east and Rovi to the west and south. Bokona is a predominantly agricultural country. Its major exports are hay, maize and cassava. It relies on Badjan, the main sea port of Rovi, for the importation and exportation of goods and services.

Last year a strange pest ("Antoa") that affected grazing areas and could spread into natural areas, attacked farmers’ hay fields in Rovi with disastrous consequences. Indeed, 80 percent of expected harvest yields were lost, and Rovi, in the circumstances, became a net importer of hay. Early this month, several communities in Bokona reported the pest infestation on their pasture land. The infestation is spreading rapidly and could spread into a nearby national park.

You are the adviser to the Government of Bokona on phytosanitary matters. Bokona and its neighbours are all parties to the International Plant Protection Convention (IPPC) and the Convention on Biodiversity (CBD).

a. What could have been the causes/sources of the pest infestation of pasture lands in Bokona?

b. What are Bokona’s obligations under the IPPC in relation to the outbreak of the infestation?

c. Bokona has no legislation to implement the IPPC. Outline the measures that Bokona can adopt to implement the IPPC.

d. What are the possible contents of such legislation?

e. What measures can Bokona adopt to control/contain the spread of the "Antoa" pest infestation?

Sample results of group discussions

These results are not all inclusive but are the results of group discussions that were correct.

1. What could have been the causes/sources of the pest infestation of pasture lands in Bokona?

2. What are Bokona’s obligations under the IPPC in relation to the outbreak of the infestation?

3. Bokona has no legislation to implement the IPPC. Outline the measures that Bokona can adopt to implement the IPPC.

4. What are the possible contents of such legislation?

5. What measures can Bokona adopt to control/contain the spread of the "Antoa" pest infestation?

Bokona can immediately initiate an emergency action until it finds out more information on the pest. A PRA is then conducted to understand the risks; based on the PRA, the following types of measures may be taken:

Exercise 2: Pest risk analysis

Described by Alan MacLeod[9], Gritta Schrader[10] and Richard Baker[11]

Introduction

Anoplophora glabripennis (Coleoptera: Cerambycidae) is a serious wood boring pest of a number of hardwood tree species in China. It spread to North America in the 1990s (http://www.aphis.usda.gov/ppq/ep/alb/) and an outbreak of A. glabripennis has been reported in Austria.

Workshop participants were given the opportunity to conduct a pest risk analysis on this organism, which has the characteristics of both an invasive alien species and a potential quarantine pest.

Methods

A PRA template document was devised for use by workshop participants (see table 1). The template consists of a series of questions arranged to be consistent with ISPM 11 [2004]: Pest risk analysis for quarantine pests, including analysis of environmental risks and living modified organisms (available at http://www.ippc.int/IPP/En/ispm.jsp).

Information about the pest was provided in the form of a data sheet (available at http://www.eppo.org/QUARANTINE/Data_sheets/anolgl/dsanolgl.html). Germany was chosen as the PRA area. Basic information about the climate of Germany and some data concerning the distribution of A. glabripennis host trees in Germany were also provided.

Results

Using all information provided and any other expert opinion available, workshop participants were able to successfully complete a pest risk analysis on A. glabripennis for Germany.

Discussion

The template (table 1) simplifies the factors that should be considered when conducting a pest risk analysis as described in ISPM 11. PRAs do not need to be very complex. They should be only as detailed as is technically justified. The advantage of using a PRA system structured as in the template is that where information is available questions can be answered very fully, yet where there is a lack of information questions can be answered on the basis of expert judgement.

Workshop participants found the exercise useful. There were some differences in how questions were interpreted and how best to answer questions. Such uncertainty about pest risk analysis demonstrates the need for more specific guidance on how pest risk analyses should be conducted. Providing examples is an excellent way to illustrate good practice. Sharing pest risk analyses and closer international cooperation between officials will encourage Plant Health Services to conduct pest risk analyses.

Sample results of the exercise are presented in table 2.

Table 1: A template for pest risk analysis as used for the exercise.

STAGE 1: PRA INITIATION

1. What is the name of the pest?


2. What is the reason for the PRA?


3. What is the PRA area?


STAGE 2: PEST RISK ASSESSMENT

4. Does the pest occur in the PRA area or does it arrive regularly as a natural migrant?


5. Is there any other reason to suspect that the pest is already established in the PRA area?


6. What is the pest’s current regulatory status in the PRA area?


7. Could the pest enter the PRA area?


8. What are its host plants?


9. What hosts are of economic and/or environmental importance in the PRA area?


10. If the pest needs a vector, is it present in the PRA area?


11. What is the pest’s present geographical distribution?


12. Could the pest establish outdoors in the PRA area?


13. Could the pest establish indoors (in glasshouses/shadehouses etc.) in the PRA area?


14. How could the pest spread within the PRA area?


15. How quickly could the pest spread within the PRA area?


16. Does the pest cause serious economic and/or environmental damage in its current area of distribution?


17. What is the pest’s potential to cause economic and/or environmental damage in the PRA area?


18. Conclusion of the pest risk assessment: To what extent can the pest enter, establish and cause serious economic and/or environmental damage in the PRA area?


STAGE 3: PEST RISK MANAGEMENT

19. What are the prospects for continued exclusion?


20. What are the prospects of eradication?


21. What management options are available for containment and control?


Conclusion of the pest risk analysis


Major uncertainties and further work


References/Documentation in support of the pest risk analysis:

Name of Pest Risk Analyst:

Date:

Address:

Table 2: Sample results for the PRA exercise.

STAGE 1: PRA INITIATION

1. What is the name of the pest?

  • Anoplophora glabripennis

2. What is the reason for the PRA?

  • Pest status (distribution) changed elsewhere (U.S. infestation originated from China)
  • Absent from Germany, potential quarantine pest
  • Intercepted in the U.K.
  • Identify/confirm level of risk presented
  • Identify pathways (already known that dunnage and wood packaging are major pathways)

3. What is the PRA area?

  • Germany

STAGE 2: PEST RISK ASSESSMENT

4. Does the pest occur in the PRA area or does it arrive regularly as a natural migrant?

  • Does not occur in PRA area (no evidence)
  • Annual surveying required
  • No natural incursion anticipated, but potential for entry with imports high

5. Is there any other reason to suspect that the pest is already established in the PRA area?

  • No reason (based on information presented in text)

6. What is the pest’s current regulatory status in the PRA area?

  • For purposes of exercise, not listed as a regulated pest
  • As stated in ISPM 20: Guidelines for a phytosanitary import regulatory system, non-listed pests can be considered of potential quarantine risk
  • Emergency measures could be applied with technical justification forthcoming

7. Could the pest enter the PRA area? (pathway?)

Yes:
  • All forms of wood packaging and dunnage
  • Migration from neighbouring countries
  • Nursery stock ruled out (due to understanding of biology)

8. What are its host plants?

  • Broad host range (c. 22 genera of trees)
  • Polyphagous beetle
  • Oaks not thought to be host
  • Majority of Germany’s tree species at risk

9. What hosts are of economic and/or environmental importance in the PRA area?

  • Fruit trees
  • Poplars
  • Acer spp.
  • Major forest tree species of Germany

10. If the pest needs a vector, is it present in the PRA area?

  • No vectors thought to be involved

11. What is the pest’s present geographical distribution?

  • Asia (Taiwan, China, Korea) - Eradicated from Japan (may need supporting data)
  • North America (U.S., Canada now)
  • Ecuador (inc. Galapagos)
  • Austria (information from workshop participants)

12. Could the pest establish outdoors in the PRA area?

Yes:

  • Climate: Temperature range in Germany not as extreme as established range in China. Therefore, outdoor establishment in Germany highly likely
  • Host range: Ample host range presented

13. Could the pest establish in protected environments in the PRA area?

  • Protected environment = glasshouse: no, host plants are not normally grown in protected conditions
  • Protected area in terms of conservation areas: yes, establishment is possible

14. How quickly could the pest spread within the PRA area?

  • Natural spread: slow, about 300 m/year
  • Human-assisted spread: rapid

15. How would this happen?

  • Natural spread:

    • adult beetles: mostly short-distance flights

  • Potential spread through actions of society:

    • movement of firewood
    • distribution through commercial transport
    • missed interceptions could be distributed very quickly (very industrialized PRA area)

  • Often present for years before signs evident

16. Does the pest cause serious economic and/or environmental damage in its current area of distribution?

Yes
· China: Poplar wood damaged by A. glabripennis larvae can be downgraded and lose value by up to 46%. Structural weakening by the larvae of trees in urban regions poses a danger to pedestrians and vehicles from falling branches. Damage to the fruiting shoots of fruit trees results in particular economic loss.

· USA: suppressing a 1996 infestation in New York State cost more than US$ 4 million

17. What is the pest’s potential to cause economic and/or environmental damage in the PRA area?

  • High potential for both economic and environmental damage in Germany:

    • ornamental trees
    • fruit trees
    • native forest species

  • Obvious damage likely, therefore detailed cost-benefit analysis not required when measures considered

18. Conclusion of the pest risk assessment: To what extent can the pest enter, establish and cause serious economic and/or environmental damage in the PRA area?

  • Overall pest risk assessment:

    • potential risk for entry - HIGH
    • potential for establishment - HIGH
    • potential for damage - HIGH

  • Overall assessment - HIGH RISK

STAGE 3: PEST RISK MANAGEMENT

19. What are the prospects for continued exclusion?

  • If assumption that pest is absent then prospects for continued exclusion reasonably good (clear pathway), but depending strongly on efficacy of inspection and interception

20. What are the prospects of eradication?

Limited prospects for eradication:
· Hard to identify at earliest stages of population development

· Dependent on early detection of populations

· Eradication efforts in the U.S. are not complete

· Anecdotal information indicates that Austria’s eradication measures have initially failed

· High costs

21. What management options are available for containment and control?

  • Tree removal and destruction
  • Stem injection, root application insecticides
  • Monitoring
  • Acoustic devices for detection
  • Use of pheromones for trapping
  • Treatment of packaging and dunnage as described in ISPM 15

CONCLUSIONS

Conclusion of the pest risk analysis

  • High risk of entry, establishment and damage, because of the pathways, availability of hosts, suitability of climate, and impacts in China and the U.S.


  • Prospects for continued exclusion reasonably good if ISPM 15 is implemented globally and inspection and interceptions are effective

  • High costs of eradication

Major uncertainties and further work

  • Status in rest of Europe

  • PRAs in rest of Europe

  • Detailed information on the magnitude of potential environmental and economic impacts

  • Detection methods

  • More detailed analysis of adaptability to European climate

  • Research on chemicals (pheromones and pesticides)

  • Taxonomic situation needs work

  • Implementation of ISPM 15
    Communications:

  • All authorities and levels of government involved need to be brought into communications loop

  • Engagement of stakeholders (to achieve workable solution)

  • Conservation groups

  • Other EU members

  • Trading partners (those exporting to PRA area)

  • Countries dealing with pest already

Exercise 3: Weed risk assessment

About the weed risk assessment system

The weed risk assessment (WRA) system, as used in Australia and elsewhere, is a question-based scoring method. Using the WRA involves answering up to 49 questions on the new species to be imported. The questions include information of the plants; climatic preferences, biological attributes, reproductive and dispersal method. The WRA uses the responses to the questions to generate a numerical score. The score is used to determine an outcome: accept, reject or further evaluate for the species. The WRA also makes a prediction as to whether a species may be a weed of agriculture or the environment.

How to answer the WRA system’s questions

The weed risk assessment question sheet (Form A) and weed risk assessment scoring sheet (Form B) for the WRA system are included below in this appendix. Answers to most of the questions in the system are yes (y), no (n) or don’t know (leave blank). A few questions require a number as a response.

How the WRA system generates a score

A typical score for a question is: Yes =1 point, No = -1 or 0, and Don’t know = 0.

The climate (see question 2) and weed elsewhere (see question 3) questions differ from the typical scoring system in that they generate a score using a weighting system. The score given for questions 2.01 and 2.02 is used to weight the scores for ´yes’ answers in the weed elsewhere questions (3.01 to 3.05). The quality of climate data greatly affects the climate match. A good climate match increases the probability that a species will behave the same way in Australia as it does overseas. The weediness score increases if the information used to produce the climate match is not comprehensive, because of the greater uncertainty introduced by the data.

Two other questions do not fit into the standard scoring system. A score of ´no’ for question 3.01, whether a plant has naturalized overseas, is modified by the score to question 2.05, its history of repeated export. Species with repeated introductions outside of their native range that have not established are a lower risk. Question 6.07, the minimum generative time, requires the input of a numerical score. This generative time is standardized by the use of a correlation factor (‘1 year’ scores 1, ‘2 - 3 years’ scores 0, ‘greater than or equal to 4 years’ scores -1).

The system compares the total score for a species to the critical values to determine the recommendation for the species. The threshold values for the system are, if the plant scores: less than 1, accept the plant for import; greater than 6, reject the importation of the plant; and from 1 to 6, further evaluation of the plant.

The threshold values are the product of the assessment of over 370 species. The species used for the calibration of the system ranged from severe agricultural and environmental weeds to benign and beneficial plants.

The system tallies the number of questions answered in each section. The WRA system allows for knowledge gaps, while still requiring responses to a minimum number of questions in each of its three different categories. The minimum number of questions for each section is: 2 for section A, 2 for section B and 6 for Section C.

The WRA system has some capacity to suggest the type of ecosystems likely to be affected by the plant assessed. The system indicates if the plant is more likely to be a specific weed of agriculture or the general environment, once it has assessed the plant’s potential to become a weed in Australia. A species may be assessed to be a weed of both categories. The partitioning helps to identify areas most at risk from the characters assessed for the species.

Do I need a computer?

The WRA system was developed to allow an assessment to be made without a computer (Form A). Form B sets out the method for manual calculation of the final score.

What computer software do I require to run the WRA system?

The WRA system is designed to run on Microsoft® Excel version 5.x. It may be run on either a Windows or Macintosh computer. The system is also in the process of being adapted to run under Access 2.0 and 7.0.

If you would like a copy of the WRA Excel program contact the Department of Agriculture, Fisheries and Forestry Australia, Plant Biosecurity (Web site: www.affa.gov.au).

Using the WRA Excel spreadsheet

The WRA Excel spreadsheet consists of two worksheets. The risk assessment (RA) worksheet is the species assessment questionnaire (Form A). This worksheet can be filled out manually or by using the run command. The WRA worksheet is dynamically linked to the second worksheet, the species sheet. This species worksheet is the data worksheet for the system. All species assessed under the system are stored in this worksheet. New species added to the RA worksheet are listed at the bottom of the species list.

Risk assessment sheet buttons

Run

Runs the dialogue driven risk assessment. Alternatively, manual entry is possible.

Get

This button has two functions. It brings the responses for a specified species from the Species sheet to the RA sheet. Also new species can be added to the list by selecting ‘new’ in the pop-up box. The system will you to type the genus and species, common name and author into a pop-up box.

Store

Transfers the current responses in the RA sheet to the Species sheet. Note that this does not save results to disk (see save).

Species

Switches to the Species worksheet.

Save

Saves the current state of the system to disk.

Help

Provides information on the operation of the system, including discussion of the questions and information on button functions.

Print report

Creates a one page report of the risk assessment, Form A. Prints this report on the currently selected printer.

Species sheet buttons

Get

Allows you to find a species or add a new one to the list. It is possible to enter and modify responses directly on the species sheet but the scores will not be updated. To update the score, the species will need to be moved to the RA sheet using the RA sheet Get button and then restored to the species sheet using the RA Store button.

Delete

Delete a species from the sheet.

Sort

Sorts the species sheet alphabetically by botanical name.

RA

Switches to the RA worksheet.

Save

Saves the current state of the system to disk.

Help

Provides information on the operation of the system.

How should I interpret the questions in the WRA system?

The weed risk assessment system consists of 49 questions.

A description of each question has been developed (see table 3 below).

Users of the WRA should try to follow these descriptions so that all users of the system answer the questions consistently.

Table 3: Description of questions used in the weed risk assessment system in Australia.


History/biogeography

1

Domestication/cultivation


Is the species highly domesticated? If answer is ‘no’ go to Question 2.01

1.01

The taxon must have been cultivated and subjected to substantial human selection for at least 20 generations. Domestication generally reduces the weediness of a species by breeding out noxious characteristics.


Has the species become naturalized where grown?

1.02

Is a domesticated plant, which has introduced from another region, growing, reproducing and maintaining itself in the area in which it is growing. A ‘yes’ answer to question 1.01 will be modified by the response to this question.


Does the species have weedy races?

1.03

Only answer this question if the species you are assessing is a sub-species, cultivar or registered variety of a domesticated species. If the taxon is a less weedy subspecies, variety or cultivar, then there must be good evidence that it does not retain the capacity to revert to a weedy form. A ‘yes’ answer to question 1.01 will be modified by the response to this question.

2

Climate and distribution


Species suited to Australian climates (0 - low; 1 - intermediate; 2 - high)

2.01

This question applies to any one Australian climate type, or more than one. Ideally, base the climate matching on an approved computer prediction system such as CLIMEX, BIOCLIM or Climate. If no computer analysis is carried out then assign the maximum score (2).


Quality of climate match data (0 - low; 1 - intermediate; 2 - high)

2.02

The score for this question is an indication of the quality of the data used to generate the climate analysis. Reliable specific data scores 2, general climate references scores 1, broad climate or distribution data scores 0. If a computer analysis was not carried out assign the maximum score of 2.


Broad climate suitability (environmental versatility)

2.03

Score ‘yes’ for this question if the species is found to grow in a broad range of climate types. Output from the climate matching program may be used for this question. Otherwise base the response on the natural occurrence of the species in 3 or more distinct climate categories. Use the map of climatic regions provided or one available in a comprehensive atlas.


Native or naturalized in regions with extended dry periods

2.04

The species is able to grow in areas with rainfall in the driest quarter less than 25 mm. Plants from this group may potentially grow and survive in arid Australian conditions.


Does the species have a history of repeated introductions outside its natural range?

2.05

This history should be well documented. A potential weed must have opportunities to show its potential. A score for question 2.05 will modify the score for a ‘no’ answer to question 3.01. Species with repeated introductions that have not established are a lower risk.

3

Weed elsewhere


Naturalized beyond native range

3.01

A naturalized species will be cited in floras of localities which are clearly outside of the native range. If the native range is uncertain and the known extent of the naturally growing plants is within the area of uncertainty then the answer is ‘don’t know’.

3.02

Garden/amenity/disturbance weed The plant is generally an intrusive weed of gardens, parklands, roadsides, quarries, etc. This question carries less weight than 3.03 or 3.04. If a plant is listed as a weed in relevant references but the type of weed is uncertain or it is a minor weed - score ‘yes’ for 3.02.

3.03

Weed of agriculture/horticulture/forestry The plant is generally a weed of agriculture/horticulture/forestry and causes productivity losses and/or costs due to control. This question carries more weight than 3.02. If a plant is listed as a weed in relevant references but the type of weed is uncertain or it is a minor weed - score ‘yes’ for 3.02.


Environmental weed

3.04

The plant is documented to alter the structure or normal activity of a natural ecosystem. This question carries more weight than 3.02. If a plant is listed as a weed in relevant references but the type of weed is uncertain or it is a minor weed - score ‘yes’ for 3.02.

3.05

Congeneric weed Documented evidence that one or more species, with similar biology, within the genus of the species being evaluated are weeds.


Biology/ecology

4

Undesirable traits

4.01

Produces spines, thorns or burrs The plant possesses a structure on the plant known to cause fouling, discomfort or pain to animals or man. If the taxon is a thornless subspecies, variety or cultivar, then there must be good evidence that it does not retain the capacity to revert to a thorny form.

4.02

Allelopathic The plant is well documented as a potential suppressor of the growth of other species by chemical (e.g. hormonal) means. Such evidence is rare throughout the whole plant kingdom.


Parasitic

4.03

The parasite must have a detrimental effect on the host and the potential hosts must be present in Australia. This question includes wholly and semi-parasitic plants. Such plants are rare.


Unpalatable to grazing animals

4.04

Consider the plant with respect to where the plant has the potential to grow and if the herbivores present could keep it under control. This trait may be found at any stage during the lifecycle of the plant and/or over periods of the growing season.


Toxic to animals

4.05

There must be a reasonable likelihood that the toxic agent will reach the animal, by grazing or contact. Some species are mildly toxic but very palatable and could cause problems if heavily grazed.


Host for recognized pests and pathogens

4.06

The main concerns are plants that are hosts of toxic pathogens and alternate or alternative hosts of crop pests and diseases. Where suitable alternative or alternate hosts are already widespread in cropping or natural systems the answer should be ‘no’ unless the species will affect the current control strategies for the pathogen or pest. Apply a reasonable level of specificity; a pathogen of an entire family, such as takeall, should not be the basis for answering ‘yes’ for an individual species.


Causes allergies or is otherwise toxic to humans

4.07

This condition must be well documented and likely to occur under normal circumstances, for example by physical contact or inhalation of pollen from the species.


Creates a fire hazard in natural ecosystems

4.08

This question applies to species that have a documented growth habit that leads to the rapid accumulation of fuel for fires when growing in natural or unmanaged ecosystems.


Is a shade tolerant plant at some stage of its life cycle

4.09

Shade tolerance can enhance the invasive potential of a species.


Grows on infertile soils

4.10

Australian soils are generally very infertile. Species that tolerate low nutrient levels could potentially grow well here. Legumes, tolerant of low soil phosphorus, are a particular concern since they would also modify the soil environment.


Climbing or smothering growth habit

4.11

This trait includes fast-growing vines and ivies that cover and kill or suppress the growth of the supporting vegetation. Plants that rapidly produce large rosettes could also score for this question.


Forms dense thickets

4.12

The thickets produced should obstruct passage or access, or exclude other species. Woody perennials are the most likely candidates, but this question may include densely growing grasses.

5

Plant type

5.01

Aquatic The question includes any plants normally found growing on rivers, lakes and ponds. These species have the potential to choke waterways and starve the system of light, oxygen and nutrients. Consequently, the score is high (5).


Grass

5.02

A large proportion of the grass family (Poaceae/Gramineae) are weeds in some context. As with congeneric weed species, there is a high probability that a species from this family will be a weed.


Nitrogen-fixing woody plant

5.03

A large proportion of woody legumes (Family Leguminosae/Fabaceae) are weeds, particularly of conservation areas. As with congeneric weed species, there is a high probability that a species from this family will be a weed.


Geophyte

5.04

Perennial plants with tubers, corms or bulbs. This question is specifically to deal with plants that have specialized organs and should not include plants merely with rhizomes/stolons (see 6.06). Plants from this group can be particularly difficult to eradicate from a site.

6

Reproduction


Evidence of substantial reproductive failure in native habitat

6.01

Predators and other factors present (e.g. disease) in the native habitat can cause substantial reductions in reproductive capacity. The reproductive output of a species may greatly increase when the plant grows in areas without these factors.


Produces viable seed

6.02

If the taxon is a subspecies, variety or cultivar, it must be indisputably sterile. The male plants of a dioecious species are regarded as seed producers.


Hybridizes naturally

6.03

A ‘yes’ answer for this question requires documented evidence of interspecific hybrids occurring, without assistance, under natural conditions.


Self-fertilization

6.04

Species capable of self seeding, can spread from seed produced by an isolated plant.


Requires specialist pollinators

6.05

The invasive potential of the plant is reduced if the species requires specialist pollinating agents that are not present or rare in Australia.


Reproduction by vegetative propagation

6.06

The plant must be capable of increasing its numbers by vegetative means. This may include reproduction by: rhizomes, stolons or root fragments, suckers or division.


Minimum generative time (years)

6.07

This is the time from germination to production of viable seed, or the time taken for a vegetatively reproduced plant to duplicate itself. The shorter the timespan, the more weedy a plant is likely to be. The score for this trait uses the correlation factor (‘1 year’ scores 1, ‘2 - 3 years’ scores 0, ‘greater than or equal to 4 years’ scores -1).

7

Dispersal mechanisms


Propagules likely to be dispersed unintentionally

7.01

Propagules (any structure, sexual or asexual, which serves as a means of reproduction), unintentionally dispersed resulting from human activity. An example is plants growing in heavily trafficked areas such as farm paddocks or roadsides.


Propagules dispersed intentionally by people

7.02

The plant has properties that make it attractive or desirable, such as an edible fruit, an ornamental or curiosity. The species is readily collected as a cutting or seed. This group includes most horticultural plants.


Propagules likely to disperse as contaminants of produce

7.03

Produce is the economic output from any agricultural, forestry or horticultural activity. An example is grain shipments that contain seeds of weed species.


Propagules adapted to wind dispersal

7.04

Documented evidence that wind significantly increases the dispersal range of the propagule. An example is an achene with a pappus. This group includes tumbling plants and plants with seeds contained within an explosive capsule or pod.


Propagules buoyant

7.05

This question includes any structure containing the propagule that typically becomes detached from the plant and is buoyant. An example is a pod of a legume. This is a limited method of distribution of land plants.


Propagules bird dispersed

7.06

Any propagule that may be transported and/or consumed by birds, and will grow after defecation. An example is small red berries with indigestible seeds.


Propagules dispersed by other animals (externally)

7.07

The plant has adaptations, such as burrs, and/or grows in situations that make it likely that propagules become temporarily attached to the animal. This can include the spread of plants parts on clothing. This dispersal group includes seeds with an oily or fat-rich outgrowth that aids in ant seed dispersal.


Propagules dispersed by other animals (internally)

7.08

The propagules are eaten by animals, dispersed and will grow after defecation.

8

Persistence attributes


Prolific seed production

8.01

The level of seed production must be met under natural conditions and applies only to viable seed. For grasses and annual species this rate should be (>5 000-10 000/m2/year), for woody annual a rate of (>500/m2/year) would be considered high. Specific data on this attribute may be unavailable, however, an estimate can be made from the seed/plant and the average size of the plant.


Evidence that a persistent propagule bank is formed (>1 yr)

8.02

Greater than 1 percent of the seed should remain viable after more than one year in the soil. This bank may include both canopy and soil seed banks. Long seed viability increases a plant’s invasive potential.


Well controlled by herbicides

8.03

Documented evidence is required for good chemical control of the plant. This control must be acceptable in the situations in which it is likely to be found. The chemical management should be safe for other desirable plants that are likely to be present. This information will be poorly documented for most non-agricultural plants.


Tolerates or benefits from mutilation, cultivation or fire

8.04

Plants that tolerate or benefit from such disturbance may out-compete other species. This question does not apply to seed banks.


Effective natural enemies present in Australia

8.05

A known, effective, natural enemy of the plant may or may not be present in Australia. The answer is ‘don’t know’ unless a specific enemy/enemies are known.

Assessments may be entered manually into Form A (see p. 280) and the final score calculated by reference to Form B (see p. 281).

Acknowledgements

The WRA system was developed by Dr Paul Pheloung during his employment in Western Australian Department of Agriculture. Input from a wide range of contributors has been instrumental in the finalisation of the WRA system. During the calibration phase, input, including assessments using the system and comments on the system, was received from scientists from 13 organizations from both Australia and New Zealand. After the system was endorsed by the Australian Weeds Committee it was released for comment to stakeholders of the Australian Quarantine and Inspection Service (AQIS) and the Australian Nature Conservation Agency (now a group within Environment Australia), the two Commonwealth agencies with an interest in the regulation of imported plants. Comments from both groups were used to increase the effectiveness and clarify the questions used in this system; this contribution is greatly acknowledged.

Form A: Weed risk assessment question sheet.

Answer yes or no, or leave blank, unless otherwise indicated

Question sheet (see p. 280)


Botanical name:


Outcome:

Common name:


Score:

Assessor:



Biogeography/historical

A

1

Domestication/cultivation

1.01

Is the species highly domesticated?


C

1.02

Has the species become naturalized where grown?


C

1.03

Does the species have weedy races?



2

Climate and Distribution

2.01

Species suited to Australian climates (0-low; 1-intermediate; 2-high)

2


2.02

Quality of climate match data (0-low; 1-intermediate; 2-high)

2

C

2.03

Broad climate suitability (environmental versatility)


C

2.04

Native or naturalized in regions with extended dry periods



2.05

Does the species have a history of repeated introductions outside its natural range?


C

3

Weed Elsewhere

3.01

Naturalized beyond native range


N

3.02

Garden/amenity/disturbance weed


A

3.03

Weed of agriculture


E

3.04

Environmental weed



3.05

Congeneric weed


Biology/Ecology

A

4

Undesirable traits

4.01

Produces spines, thorns or burrs


C

4.02

Allelopathic


C

4.03

Parasitic


A

4.04

Unpalatable to grazing animals


C

4.05

Toxic to animals


C

4.06

Host for recognized pests and pathogens


N

4.07

Causes allergies or is otherwise toxic to humans


E

4.08

Creates a fire hazard in natural ecosystems


E

4.09

Is a shade-tolerant plant at some stage of its life cycle


E

4.10

Grows on infertile soils


E

4.11

Climbing or smothering growth habit


E

4.12

Forms dense thickets


E

5

Plant type

5.01

Aquatic


C

5.02

Grass


E

5.03

Nitrogen-fixing woody plant


C

5.04

Geophyte


C

6

Reproduction

6.01

Evidence of substantial reproductive failure in native habitat


C

6.02

Produces viable seed.


c

6.03

Hybridizes naturally


c

6.04

Self-compatible or apomictic


c

6.05

Requires specialist pollinators


c

6.06

Reproduction by vegetative fragmentation


c

6.07

Minimum generative time (years)

1

A

7

Dispersal mechanisms

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)


C

7.02

Propagules dispersed intentionally by people


A

7.03

Propagules likely to disperse as a produce contaminant


C

7.04

Propagules adapted to wind dispersal


E

7.05

Propagules buoyant


E

7.06

Propagules bird dispersed


C

7.07

Propagules dispersed by other animals (externally)


C

7.08

Propagules survive passage through the gut


C

8

Persistance attributes

8.01

Prolific seed production (>2000/m2)


A

8.02

Evidence that a persistent propagule bank is formed (> 1 yr)


A

8.03

Well controlled by herbicides


A

8.04

Tolerates, or benefits from, mutilation or cultivation


E

8.05

Effective natural enemies present in Australia


A = agricultural, E = environmental, N = nuisance, C = combined.

Form B: Weed risk assessment scoring sheet.


[9] Central Science Laboratory, Sand Hutton, York, YO41 1LZ, UK;
[10] Zoological Institute, Technical University of Braunschweig, Spielmannstrasse 8, D-38092, Braunschweig, Germany; e-mail: a.macleod@csl.gov.uk, g.schrader@bba.de, r.baker@csl.gov.uk
[11] Central Science Laboratory, Sand Hutton, York, YO41 1LZ, UK;

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