As appointed representatives of the European Union's Scientific Forum on Invasive Alien Species, we wish to point out that the EU regulation states priority should be given to the listing of invasive species “that are not yet present in the Union or are at an early stage of invasion” (see M. Lehtiniemi Nature 533, 321; 2016).
The risk assessments needed to include species on the EU list of concern were already available for most of the 37 species (see go.nature.com/gigftz) and were a natural starting point. Moreover, listing is a political process: actions to protect biodiversity are weighed against factors such as socio-economic interests. Adequate evidence is necessary to ensure that proper action is taken.
Notably, none of the targeted 37 species is established in all EU member states, and all have potential for future spread (see go.nature.com/28vtjpk).
Any member state, including those where Lehtiniemi and colleagues are based, can develop and submit risk assessments for candidate species. The scientific forum assesses these according to regulation criteria. Member states and the European Commission then decide whether to regulate species at the EU level.