A demarcation of risk categories for invasion risk assessments using the Harmonia+ protocol

This technical note presents a proposal for the demarcation of risk classes based on output from the Harmonia+ protocol for the risk assessment of introduced organisms (D'hondt et al., 2015). Based on simulations, we present threshold values for classifying species into categories of low, medium or high risk (three-level categorization), and of very low, low, medium, high or very high risk (five-level categorization). The note also briefly discusses other possible values for delimiting categories. Moreover, R scripts are attached that should allow users to perform simulations themselves, as to define threshold values in case protocol settings become customized.