Monitoring and surveys

Six-year evaluation of the Scheldt Estuary

In 2022 and 2023, Waardenburg Ecology worked with HKV, Antea Group Belgium and Ghent University within the 'Schelde in Beeld' consortium on the six-yearly evaluation of the Scheldt Estuary. In addition to declines, we also noted positive trends. For flora and fauna, we looked at the development of habitats and individual species-groups such as macrozoobenthos, fish, birds and marine mammals.

Development of habitats and flora and fauna

The report provides a complete picture of the current state of the Scheldt Estuary in terms of the main functions for safety, accessibility and nature, for which the Netherlands and Flanders have formulated policy objectives.

The Scheldt Estuary is a complex system that is constantly changing. Natural processes are influenced by human activities such as the deepening of navigation channels and in relation to flood safety. The evaluation looked at developments in the field of hydrodynamics, morphology, water quality and functions for safety, accessibility and nature. Colleagues from Waardenburg Ecology focused mainly on the development of habitats and flora and fauna.

The shape and location of the flats, mudflats and salt marshes in the estuary are becoming increasingly more stable, resulting in less rejuvenation of habitats and changes to their elevation. This has a negative impact on the vegetation, the quality of which is still insufficient. Managed retreat and nature restoration measures inside and outside the dikes have led to an increase in the areas of high-quality habitats and a positive response from animal and plant species.

Decline and positive trends

Not all standards of the Water Framework Directive (WFD), that relate to surface habitats have yet been met. Positive trends have been noted in some areas, such as an increase in the macrozoobenthos and the growth of the seal population. On the other hand, many species groups have declined, such as many species of coastal breeding birds, phytoplankton and diadromous fish (species that reproduce in estuaries and migrate to the sea as adults). It is certain that not all objectives have yet been achieved and that non-native species remain an issue at almost every level of the fodd chain.

The evaluation was carried out on behalf of the Flemish-Dutch Scheldt Commission (VNSC). The result of the collaboration is available in the T2021 report that describes the developments in the estuary in the period 2016-2021.
Link to the reports (only in Dutch)