Consistent accuracy of the Australian weed risk assessment system across varied geographies

Abstract

The ecological and economic advantages of preventing introduction of species likely to become invasive have increased interest in implementing effective screening tools. We compared the accuracy of the Australian Weed Risk Assessment (WRA) system with that across the six geographies in which it has been tested (New Zealand, Hawaii, Hawaii and Pacific Islands, Czech Republic, Bonin Islands and Florida). Inclusion in four of the tests of a secondary screening tool, developed to reduce the number of species requiring further evaluation, decreased the number of species with that outcome by over 60% on average. Averaging across all tests demonstrated that the WRA system accurately identified major invaders 90%, and non‐invaders 70%, of the time. Examined differently, a species of unknown invasive potential is on average likely to be correctly accepted or rejected over 80% of the time for all of these geographies when minor invaders are categorized as invasive. Whereas increasing consistency in definitions and implementation would facilitate understanding of the general application of the WRA system, we believe that this tool functions similarly across islands and continents in tropical and temperate climates and has been sufficiently tested to be adopted as an initial screen for plant species proposed for introduction to a new geography.

Beyond protocols: improving the reliability of expert-based risk analysis underpinning invasive species policies

“…The protocol uses the answers to 49 questions concerning the species' biology, biogeography, and behaviour elsewhere, to classify a plant species according to its risk of becoming invasive (Hulme 2012). Based on the precautionary principle it is using species scores to classify species as permitted, rejected, or prohibited, without recourse to expert discussion (Gordon et al 2008;Pheloung et al 1999). Such a straightforward approach is useful for species which are not yet or only locally established, so as to effectively prevent entry of any potentially harmful organism.…”

Traits related to biological invasion: A note on the applicability of risk assessment tools across taxa

“…A comparison of the AWRA and other models (such as Reichard and Hamilton [2007]) found the AWRA to be the most accurate (Jefferson et al 2004). The AWRA has since been modified and tested for invasive plants in New Zealand (Pheloung et al 1999), the Hawaiian Islands (Daehler and Carino 2000), other Pacific islands (Daehler et al 2004), Japan (Kato et al 2006), the Czech Republic, and Florida (Gordon et al 2008), with fairly consistent results. However, when the AWRA was tested for invasive plants in Canada, it was found to reject a high proportion of non-weedy species (McClay et al 2010).…”

Insufficient Evidence of Jatropha curcas L. Invasiveness: Experimental Observations in Burkina Faso, West Africa

“…There was no significant difference in seedling density between the sites (χ 2 =1.913; P=0.384). Based on the closest individual basic distance density estimator (individual seedling m −2 ) around J. curcas live fences, we found ≤0.01 seedlings m −2 in all monitored sites (100, 43,65,49,38,44,39, and 41 seedlings ha −1 , respectively, for Yalle, Kayero, Neboun, Metio, Tabou, Léo, Zoro, and Benaverou villages). About 70 % of the seedlings were found close to the live fence (<2.5 m), and most of them were new, i.e., from the same year (96 %) ( Table 1).…”

“…Despite the high importance of WRA conclusions [18,19,44] in predicting the spreading risks of alien crops, WRAs need to be combined with ecological field experiments to reach reliable decisions, particularly in the context of bioenergy decisions [13,51,52], which this study aims to provide empirical evidence to substantiate the widely recognized weed risk assessment models using field experiments. Quality ecological data from in situ ecological experiments and field surveys such as current population size, seed production rate, seed size, dispersal ability, dispersal vectors, and after dispersal fate of the seeds would be important data in establishing the future invasion risk of potential alien tropical biofuel crops [13,20,53].…”

“…Some other Asian and sub-Saharan African countries, with the exception of South Africa where it has been banned [34,36], still consider planting J. curcas [40][41][42][43]. Findings of high risk in other locations reflect a high probability that J. curcas could become naturalized in those areas, based on a widely recognized weed risk assessment (WRA) system [18,19,44]. Some of the regions mentioned above are characterized by a tropical wet climate [45].…”