Coordination and cooperation are necessary topics to strengthen international environmental agreements that improve action against worldwide challenges towards sustainable development and environmental protection, such as invasive alien species (IAS). This study aims to assess to what extent national and transnational cooperation and coordination influences the implementation of a supranational regulation against IAS based on an example from the European Union (EU). Data is used from a broader study, including 47 responses to an online questionnaire and 22 interviews completed by experts from two countries (Austria and Romania), together with in depth literature. Additionally, the IAS-Regulation is analyzed from the perspective of cooperation and coordination. The terms “cooperation” and “coordination” were found within the text of the IAS-Regulation 11 and nine times respectively, whereas their context was transnational and national levels mainly, and transnational, respectively. It was further acknowledged from the majority of the answers from the survey respondents that the national coordination and cooperation is weaker than the transnational level due to the influence of the national competence distribution. Results from the interviews are separated into ‘transnational’ and ‘national’ cooperation and coordination. They show that the majority of the 47 responses indicate that the distribution of competence is one of the main influencing factors on the implementation. It is concluded that the current situation of cooperation and coordination in Austria and Romania renders it difficult for the European Commission to receive a realistic view about IAS and the implementation of the IAS Regulation in the two countries; hence, it is difficult to offer helpful support especially due to poor national cooperation. The current study can serve as a blueprint for further studies. Even in regional integration contexts beyond the EU, it can prove helpful to assess the impact of different kinds of competence distribution on the implementation of common norms. Thus, this research can path the way innovatively and serve as a comparative example for similar future studies.

Invasive alien species (IAS) constitute a trans-and intracontinental challenge. With this article, we exemplify obstacles met during the implementation of the Regulation (EU) No. 1143/2014 against IAS and comparatively assess them through two case studies from two Member States, Austria and Romania, via qualitative content analysis. Challenges are identified, analyzed, and discussed based on interviews with stakeholders from both countries in the view of the three main intervention types within this Regulation: prevention, early detection, and rapid eradication and management. The obstacles, which the two Member States met, are related to creating, updating, and maintaining the Union List and to the distribution of competences, which influence the national and subnational cooperation and coordination. Financial resources, custom controls, national legislation, and awareness influence the implementation of the IAS Regulation too. This research contributes to improving knowledge about numerous details of the implementation and enforcement of this IAS-Regulation to make them more feasible, not just for scientists, but also for decisionand policymakers, business owners, and other stakeholders.