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Development of the Weed Risk Assessment system
Formalisation of Australia's current weed risk assessment procedures commenced with the Australian Weeds Committee commissioning a workshop "Screening Plants for Weediness: A Procedure for Assessing Species Proposed for Importation into Australia." in June 1994. This workshop was convened when it was recognised during the early writing stages of the National Weeds Strategy that a more systematic evaluation of new plant introductions would become a priority of the strategy. This workshop was, as one of its aims, commended to develop transparent administrative procedures for plant species introductions, aimed at minimising the introduction of new weedy plants.
The report from the workshop outlined a three tiered screening system for plant introductions. The first tier involves determining the taxonomic status of a new introduction and then checking it against current lists of permitted or not permitted species. Species that are not on these lists proceed to the pre-entry plant screening, the second tier of the system. The third tier involves post-entry evaluation of species in field studies to examine more directly the weed potential (and verify potential benefits). The three tier scheme addresses Objective 1.1 of the National Weed Strategy.
The agreed 2nd tier, pre-entry plant screening method, is the Weed Risk Assessment (WRA) system. Originally developed by Dr Paul Pheloung from the Western Australian Department of Agriculture, the new system was demonstrated at the 1994 workshop. Due to the perception that plants may behave differently in Australian conditions, and due to the large number of species involved, an efficient predictive tool was considered necessary. The system includes features not found in other comparable assessment systems. It includes characters that tend to reduce weediness in its question set, because scientists have shown that non-invasive characters can be used as a predictive tool as well as weedy characters. The large number of questions (49) reduces the effect of assessor subjectivity by reducing the weighting for any one question. The system allows for knowledge gaps, that is not all questions need be answered if the information is not available. Nevertheless there is a minimum number of questions to be answered before an assessment is made. This system may be used to assess species not well described in the general scientific literature and may only be described in botanical floras. These features increase the systems effectiveness as a pre-entry tool as the system enables an assessment from limited information sets. The WRA system also has some ability to differentiate between weeds of agriculture and weeds of the environment.
After the workshop additional work was carried out to test the effectiveness of the WRA system. Some changes were made to the system and then it was subjected to testing by a comparative analysis against the other two assessment systems using 370 species. The WRA system was found to be more decisive than the comparable methods, the method used at the time by AQIS (the Hazard or AQIS system) and a method developed by Panetta. While still rejecting those species known to be weeds, the WRA accepted more non-weedy species and also recorded less evaluate scores. A report by Dr Pheloung on the system "Determining the weed potential of new plant introductions to Australia" was submitted for consideration by various Commonwealth agencies in July 1995.
The WRA system described by Dr Pheloung's report was endorsed with a recommendation that Biosecurity Australia and a group within Environment Australia, the two Commonwealth agencies with an interest in the regulation of imported plants, release the system to stakeholders for comment. The system was well supported across the broad spectrum of groups from which comments were received. This included departments of agriculture, conservation and land management, CSIRO, seed companies, grains and horticulture peak bodies. Comments made during the consultation phase were incorporated into the system. Generally these involved clarification of the scope and intention of the questions.
Final endorsement for use of the system for the assessing all new plants entering Australia occurred on April 1997.
BA, the agency that takes action to regulate imported plants, has now formally adopted the system for assessing all new plant imports. To facilitate the process of assessment, information is being requested from prospective importers and a questionnaire has been developed. A package is currently being developed which will allow importers with the necessary expertise, or registered consultants, to conduct pre-entry assessments with the system before lodging an application to import.