Biological Invasions

, Volume 14, Issue 5, pp 987–998 | Cite as

How robust is the Australian Weed Risk Assessment protocol? A test using pine invasions in the Northern and Southern hemispheres

  • Kirsty F. McGregor
  • Michael S. Watt
  • Philip E. Hulme
  • Richard P. Duncan
Original Paper


The Australian Weed Risk Assessment protocol (WRA) is often considered the standard approach for pre-border screening of new plant introductions. Here we assess its robustness against three key criteria: ability to discriminate success or failure of species at three stages of the invasion process (introduction, naturalisation and spread); sensitivity to taxonomic range and target region; and dependence on knowledge of invasive behaviour elsewhere. We address these issues by retrospectively testing the WRA using pine (Pinus) introductions to New Zealand and Great Britain. For both regions we calculated WRA scores for 115 species, and classified all species according to whether they had been introduced, which of these had naturalised, and the extent of their naturalised distribution (spread). Using regression models, we assessed whether WRA scores could predict success at each stage. We repeated this procedure using WRA scores calculated without information on species naturalisation behaviour elsewhere. In both regions, the WRA could discriminate among species in the same genus at the introduction and naturalisation stages, but not at the spread stage. The outcome at the naturalisation stage depended on prior knowledge of naturalisation behaviour elsewhere. Without this information the WRA may be unable to distinguish among closely related species, and should be used cautiously where data on invasive behaviour elsewhere is lacking. Human selection played a strong role in the invasion process both through introducing pine species likely to naturalise in New Zealand and Great Britain in the first instance, and subsequent use of many of these species for forestry in the target regions.


Climate matching Risk assessment Exotic species Forestry Spread Weed 



This research was funded by a New Zealand Tertiary Education Commission PhD scholarship. We thank: Hazel Gatehouse for information on naturalisation records in New Zealand; Jon Sullivan for supplying additional nursery catalogues for New Zealand; the staff at SCION for their assistance in processing archived working plans; the Department of Conservation area offices throughout New Zealand for their prompt replies to our questionnaire; Dave Richardson and two anonymous reviewers for comments that improved the manuscript.

Supplementary material

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Supplementary material 1 (DOC 76 kb)
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Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Kirsty F. McGregor
    • 1
  • Michael S. Watt
    • 2
  • Philip E. Hulme
    • 1
  • Richard P. Duncan
    • 1
  1. 1.Bio-Protection Research CentreLincoln UniversityLincolnNew Zealand
  2. 2.SCIONFendalton, ChristchurchNew Zealand

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