Risk management to prioritise the eradication of new and emerging invasive non-native species

Robust tools are needed to prioritise the management of invasive non-native species (INNS). Risk assessmentis commonly used to prioritise INNS, but fails to take into account the feasibility of management. Risk managementprovides a structured evaluation of management options, but has received little attention to date. We present a risk managementscheme to assess the feasibility of eradicating INNS that can be used, in conjunction with existing risk assessmentschemes, to support prioritisation. The Non-Native Risk Managementscheme (NNRM) can be applied to any predefined area and any taxa. It uses semi-quantitative response and confidence scores to assess seven key criteria: Effectiveness, Practicality, Cost, Impact, Acceptability, Windowof opportunityand Likelihood of re-invasion. Scores are elicited using expert judgement, supported by available evidence, and consensus-building methods. We applied the NNRM to forty-one INNS that threaten Great Britain (GB). Thirty-three experts provided scores, with overall feasibility of eradication assessed as ‘very high’ (8 species), ‘high’ (6), ‘medium’ (8), ‘low’ (10) and ‘very low’ (9). The feasibility of eradicating terrestrial species was higher than aquatic species. Lotic freshwater and marine species scored particularly low. Combining risk managementand existing risk assessmentscores identified six established species as priorities for eradication. A further six species that are not yet established were identified as priorities for eradication on arrival as part of contingency planning. The NNRM is one of the first INNS risk managementschemes that can be used with existing risk assessmentsto prioritise INNS eradication in any area.