COS 136-10
A plant risk evaluation tool for assessing the invasive potential of ornamental plants
Weed Risk Assessment (WRA) methods for screening potential new plant introductions through the horticultural industry have evolved rapidly in the last decade. To be accepted as a tool to evaluate current plant inventories and new plant introductions within the industry, it is critical that a pre-screening tool not only accurately predict invasive potential of a species, but also accurately predict non-invasiveness without falsely categorized them as invasive. In this study, we developed a new abbreviated Plant Risk Evaluation (PRE) tool specific for plants originating from the ornamental industry. The 29 questions in the PRE tool were based on a combination of other WRAs. To test and compare the accuracy of the tool against the widely used Australian WRA, we used three independent evaluators. Using between 127 and 177 species known to be invasive or non-invasive (all ornamentals), each evaluator recorded the time required to complete the assessments.
Results/Conclusions
Our results showed that the two tools maintained 95-100% accuracy in predicting invasiveness (sensitivity). However, the PRE tool was consistently more accurate in predicting non-invasiveness (specificity) compared to the Australian WRA, averaging 98% compared to 39%. Despite the reduced number of questions (49 to 29), there was no difference in the time required to complete either tool. The PRE tool should not only provide growers with a method to accurately screen their current stock and potential new introductions, but also increase the probability of the tool being accepted for use by the industry as the basis for a nursery certification program.