Research Document - 2013/096
Application of an Aquatic Plant Risk Assessment to Non-Indigenous Freshwater Plants in Trade in Canada
By Crysta A. Gantz, Nicholas E. Mandrak, and Reuben P. Keller
Abstract
The economic and ecological costs associated with invasive species in North America are high, with some estimates reaching $150 - 170 billion/year (Pimentel et al. 2000; Colautti et al 2006). Ecological risk assessment tools that pre-screen species for invasiveness and are combined with effective regulations to keep high-risk species out is one way to significantly reduce these costs. For plants, we evaluated a questionnaire-style risk assessment developed by Biosecurity New Zealand and tested previously at the University of Florida and the University of Notre Dame (Gordon et al. 2012). This assessment accurately distinguished between established species and those that were introduced but failed to establish in the United States. We modified the Gordon et al. (2012) risk assessment so that all questions are relevant to Canada and then used it to evaluate species from that paper. We excluded any species that did not have a USDA hardiness zone match with Canada. The risk assessment worked well at categorizing this sample of established and not established species in Canada. An additional sample of species in trade was assessed with high accuracy for not established species, but low accuracy for established species (although the established sample size was small; 4 species).The reason an existing protocol was adapted to Canada rather than developing a new risk assessment model is that the latter would take extensive research on introduction dates, establishment and impact of non-native species, specifically for Canada. The modified Gordon et al. (2012) tool has been peer reviewed, applied successfully in several countries, and worked well to accurately distinguish established invasive from non-established species when applied to Canada.
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