Biological Invasions

, 11:1319

Developing a pre-entry weed risk assessment system for use in Japan

  • Tomoko Nishida
  • Naoko Yamashita
  • Motoaki Asai
  • Shunji Kurokawa
  • Takashi Enomoto
  • Paul C. Pheloung
  • Richard H. Groves
Original Paper


We evaluated the applicability of the Australian Weed Risk Assessment (AWRA) system in Japan. Native weeds (n = 117) and introduced plants (n = 142), whose weed status was classified by 20 plant experts, were assessed using a slightly modified version of the AWRA system designed to fit Japanese conditions. A receiver operating characteristic (ROC) curve for the system, when classifying two-thirds of the 259 taxa as weeds or non-weeds, was plotted and the area under the ROC curve was calculated. The area was 0.88 and significantly greater than 0.5. Thus, the validity of the system to classify plants was proven. The best cut-off level for the WRA score using Youden’s index was 10. When taxa whose AWRA scores were greater than 10 were regarded as weeds, the sensitivity and specificity were 0.88 and 0.78, respectively. These values were verified with the remaining one-third of the taxa. From these findings, the modified AWRA system was considered to be effective for use in Japan. However, further studies are required to set the best cut-off level in terms of maximising the benefits gained from using the system. A second screening test associated with the cut-off level also needs to be developed.


Introduced plants Japan Pre-entry screening ROC curve The Australian Weed Risk Assessment system 


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Tomoko Nishida
    • 1
  • Naoko Yamashita
    • 2
  • Motoaki Asai
    • 3
  • Shunji Kurokawa
    • 4
  • Takashi Enomoto
    • 5
  • Paul C. Pheloung
    • 6
  • Richard H. Groves
    • 7
  1. 1.Biodiversity DivisionNational Institute for Agro-Environmental SciencesTsukubaJapan
  2. 2.Forest Ecology GroupKansai Research Center, Forestry and Forest Products Research InstituteFushimiJapan
  3. 3.Integrated Weed Management Research TeamNational Agriculture Research CenterTsukubaJapan
  4. 4.Forage Productivity Research TeamNational Institute of Livestock and Grassland ScienceTochigiJapan
  5. 5.Laboratory of Wild Plant ScienceResearch Institute for Bioresources, Okayama UniversityKurashiki CityJapan
  6. 6.Office of the Chief Plant Protection OfficerDepartment of Agriculture, Fisheries and ForestryCanberraAustralia
  7. 7.CSIRO Plant IndustryCanberraAustralia

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