Invasive alien species may pose a serious threat to the typical Wadden Sea biodiversity. Many alien species remain insignificant additions to the native flora and fauna, but several invasive species can alter habitats and have long-lasting effects on native biota in the Wadden Sea.
More than fifty international and regional conventions, codes of conduct and other instruments exist that directly or indirectly deal with the spread of alien species, but an overall integrated strategy on how to deal with alien species introduced into the Wadden Sea is still lacking.
At the 11th Trilateral Governmental Wadden Sea Conference (Sylt, Germany, March 2011), the three Wadden Sea states decided to develop a common strategy for dealing with alien species in the Wadden Sea. As a first step, the 2010 Wadden Sea Day was dedicated to the theme "Neobiota in the Wadden Sea – Challenges for Nature Conservation".
In 2011, a comprehensive overview of the situation with regard to invasive alien species was presented in the report “Neobiota in the Wadden Sea”. This report has been the basis for drafting a strategic framework for dealing with alien species, which was discussed by the 12th Trilateral Governmental Wadden Sea Conference (Denmark, February 2014). It was agreed to develop a trilateral alien species management and action plan on the basis of the strategic framework.
The Working Group Alien Species (WG-AS), a working group under the Task Group Management and Monitoring (TG-MM), is currently working on the development of an alien species management and action plan. Guidance for this work is delivered by two inventory reports, "Alien species in the DutchWadden Sea: policies and management" and "Invasive alien species (IAS) policies and management in the German Wadden Sea".