Various domestic and international initiatives have elevated invasive species issues onto the policy agenda. In the invasive plants arena, risk assessment efforts have focused on classifying the invasive potential of nonindigenous plants. Currently, however, the field of risk assessment for invasive species is in an early stage of development, and there is a lack of broad scientific principles or reliable procedures for identifying the invasive potential of plants in new geographic ranges. Furthermore, identifying potential hazards may be just the first step in a more comprehensive risk assessment. At least for those regulatory decisions that may be disputed internationally or domestically, scientifically ambitious risk assessment for invasive plants is not optional. Therefore, there is a pressing need to formulate adaptable, biologically plausible methods and approaches in this emerging field that strike an appropriate balance between the demand for accuracy and precision in predicting risks and the constraints of limited information, time, and other resources.

Additional index words: Regulatory analysis, Sanitary and Phytosanitary Agreement.