PhD defence Kasper Meijer
Kasper Meijer (ConsEco)
Promotores: Prof. H. Olff, Prof. L.L. Govers, Prof. T. van der Heide; copromotor: Dr O. Franken
Status quo or status faux
The conservation status of the subtidal Dutch Wadden Sea
The Wadden Sea is one of the largest tidal ecosystems in the world and a UNESCO World Heritage Site, renowned for its extensive mudflats, diverse bird population, and seal colonies. Yet, nearly half of the area is permanently submerged. These subtidal areas are relatively unexplored, despite hosting diverse benthic communities of worms, shellfish, and crustaceans that play a crucial role in ecosystem functioning. This thesis provides the first comprehensive investigation of the underwater nature of the Dutch Wadden Sea. Through field surveys, experiments, and new analytical approaches, it reveals how species are distributed, their functional characteristics, and how these relate to disturbances within the system.
The results indicate that the current protection of the Wadden Sea is insufficient. The existing conservation framework, although extensive on paper, does not sufficiently align with ecological hotspots in the subtidal zone. As a result, many vulnerable areas remain insufficiently protected, creating only the appearance of effective conservation. Furthermore, the study demonstrates that overall biodiversity in the Wadden Sea is in decline. A synthesis of population trends over the past century reveals that many species, ranging from algae to birds, have declined significantly, with potential consequences for the ecosystem's functional integrity. Long-term monitoring and better integration of ecological knowledge into policy are essential. This thesis emphasises that restoring resilience and biodiversity in the Wadden Sea requires a transition towards truly adaptive and ecologically grounded management, in which actual ecological value, rather than legal status alone, takes centre stage.