Keeping 'one step ahead' of invasive species: Using an integrated framework to screen and target species for detailed biosecurity risk assessment

Predicting which species will become invasive in each country or region before they arrive is necessary to devise and implement measures for minimising the costs of biological invasions. Metaphorically, this is keeping one step ahead of invasive species. A structured and systematic approach for screening large numbers of species and identifying those likely to become invasive is proposed in this paper. The Pest Screening and Targeting (PeST) framework integrates heterogeneous information and data on species biogeography, biotic and abiotic factors to first determine a preliminary risk index, then uses this index to identify species for a second, more detailed, risk evaluation process to provide a final ranking. Using the PeST framework, 97 species of plant-parasitic nematodes were evaluated for their biosecurity risks to Australia. The species identified as greatest risks included both previously unrecognised and currently-recognised species. The former included Heterodera zeae, Meloidogyne graminicola, M. enterolobii, M. chitwoodi and Scutellonema bradys, while the latter included Bursaphelenchus xylophilus, Ditylenchus destructor, Globodera pallida, Heterodera glycines and H. filipjevi. Of the ten criteria used in the PeST framework, emerging pest status, pathogenicity, host range and species biogeography most strongly influenced overall risk. The PeST framework also identified species where research to fill in critical knowledge gaps will be most beneficial (e.g. Globodera tabacum, Heterodera cajani, H. filipjevi, Meloidogyne ethiopica, Pratylenchus fallax and P. sudanensis). Where data were available, the information and associated metadata gathered for the PeST framework can be used to guide biosecurity decision making; determine species which require pre border certification and target sampling at the borders.