Samenvatting

The Netherlands is dependent on artificial structures for water safety. In addition to water safety the artificial structures also provide habitat for different aquatic species. When designing artificial structures like dikes and breakwaters adjustments can be taken to increase species richness or stimulate target species.
This research is focussed on the effect of different pilot locations in the south western delta on the biodiversity. Three different pilot locations are researched, two innovative dike designs (Sint-Annaland & Hansweert) and a pilot location with breakwaters (Bath). The two dikes in Sint-Annaland and Hansweert have different designs with variation in structure and material. The pilot in Sint-Annaland is already at a climax stadium and the pilot in Hansweert is only two years old. The breakwaters in Bath are placed to create a low dynamic intertidal area for birds by reducing the velocity. In addition, the breakwater also provides hard substrate for seaweed settlement. Data is collected for the biomass, species abundance, seaweed coverage and sensor data.
The different revetment types at high elevations in Sint-Annaland show to stimulate specific seaweed species. Hillblock stimulates the presence of Ascophyllum nodosum while at the ecotop higher weights are found for the Fucus serratus. The innovative material in Hansweert allows seaweeds to grow at higher elevations but is also more susceptible for losses. The Breakwaters allow seaweeds to grow but are limited by other factors.
At the three different pilot location it can be seen that changes in material and structure effect the composition of species. Specific structures can stimulate target species, while an increase in water retention allows seaweed species to grow at higher elevations. Not all designs are applicable to every situation. As observations indicate that lava stones at breakwater are not suitable for seaweed settlement. So when specific designs are used on artificial structures they must be suitable for that location to be effective.