In recent years, research has been carried out in both areas into options and possibilities for restoring seagrass. For the Wadden Sea, it is primarily about Griend. For the south-western delta, these are Grevelingenmeer and Veerse Meer.
The importance of seagrass
Seagrass beds, such as coral reefs, mangrove forests and shellfish beds, form the basis of a healthy ecosystem. This aquatic plant forms large fields. In these fields, the water flows more slowly, causing the sludge to sink to the bottom and create clear water. Seagrass stabilizes the soil with the roots, and seagrass deposits CO with the rhizomes2 firm.
According to scientists, seagrass beds are much more efficient at storing carbon than most forests. In addition, salt marshes are of great importance for biodiversity: they act as a breeding ground for, among other things, fry of fish and shrimp, and they form a habitat and shelter for animals that live in the water and in the seabed. These in turn can serve as food for birds and fish. The sea grass beds thus form an important link in the food chain below and above water
The disappearance of a green treasure
Seagrass is a plant that occurs naturally in the Netherlands. Previously, the beaches of the Wadden Sea and the Southwest Delta were thousands of hectares large and important to nature and even the economy. For example, it was used to cover roofs, build dikes and fill mattresses. Seagrass has disappeared in most parts of Dutch waters due to the construction of Afsluitdijk, Delta Works, diseases and deteriorating water quality.
Seagrass recovery in the Wadden Sea
Restoration of seagrass in the Wadden Sea has long been a project that the Nature Monument has monitored. Research into seagrass extraction at the University of Groningen and Fieldwork Company has resulted in successes near the island of Griend in recent years.
Seagrass seeds have been sprayed into the soil with a grout sprayer and then successfully grown into plants. With the new recovery project, the Rijkswaterstaat wants to continue this favorable trend and conduct further research. One of the goals of the research is to create a new seagrass field in another location, in addition to continuing the experiment at Griend. We do this in coordination with other managers in the area and the Wadden Sea Administration.
Seagrass recovery is still in its infancy in the southwest delta. A multi-year pilot has been carried out in Grevelingenmeer to see if the quality of the area is sufficient to reintroduce seagrass. The conclusions of this pilot are promising: seagrass can survive in the Grevelingenmeer.
The next step is to expand the research to Veerse Meer and explore what is needed to create fields that can sustain themselves. The Water Framework Directive aims to have developed 5 hectares of seagrass beds in both lakes by the end of the 2027 growing season.
Large-scale restoration of seagrass is a multi-year process. Extreme weather conditions, climate change and human activities, such as land disturbance due to fishing or dredging, can, for example, make it difficult to recover seagrass.
Creating self-help seagrass beds requires a great deal of knowledge and expertise. That is why we have placed an order through a European tender. Together with Witteveen + Bos, the University of Groningen, The Fieldwork Company and Altenburg and Wymenga, work is now being done on the execution of the task. This is a total investment of 5 million euros over 5 years. The funding is made available from the Water Framework Directive. The ultimate goal is to get seagrass back permanently in the Wadden Sea and the southwestern delta.