Wet Tropics Weed Risk Assessment Page i EXECUTIVE SUMMARY

An examination of the issue of alien plant species invasions of the Wet Tropics Bioregion was conducted in order to consider management implications for the Wet Tropics of Queensland World Heritage Area. The terms of reference for the project comprised the development of a computer-based weed Risk Assessment System encompassing (i) inventory of existing weeds, plants presently found in the region that may constitute ‘sleeper ’ weeds and plants not presently found in the region that are proven environmental weeds in similar environments elsewhere; (ii) prioritisation of potential environmental threat based on explicit biogeographic/historical and biological/ecological criteria; (iii) categorisation into management categories- eg, species targeted for prevention, eradication and containment control; and (iv) consideration of appropriate management actions. This Report presents a review of Risk Assessment Systems (RASs) currently being applied or developed with the view to formulating a robust system to screen alien species that have naturalised within the bioregion. Systems reviewed were: (1) RASs for Preventative Quarantine Purposes – ie, International protocols (FAO 1996, 1998a, 1998b);Prevention or minimisation of risk of introductions to countries with comparable habitats/vulnerabilities (eg, Virtue et al. in press, Williams et al. in press); Australian protocols (Pheloung 1995, Steinke & Walto