Management realignment projects (or de-poldering projects) often aim at developing intertidal habitats in the newly created area. The development into non-vegetated intertidal habitat (i.e. mudflats) and eventually into vegetated intertidal habitat (i.e. salt marshes) depends on many factors related to the characteristics of the former polder and the conditions of the adjacent estuarine environment. Also biotic interactions (e.g. bioturbation) can play a role to which state the area will develop, vegetated or non-vegetated. Important environmental factors include:
- Emersion or inundation time
- Sedimentation rate
- Sediment composition
- Drainage
- Hydrodynamic conditions
Due to the relatively low-lying conditions of Perkpolder and its position in the transition zone between brackish and marine waters in the Western Scheldt, we expect that at first the area will develop into a non-vegetated intertidal zone, with low hydrodynamics and a relatively high sedimentation rate. If non-vegetated intertidal areas develop, the next question is how biodiversity will develop in these areas. Mudflats in estuaries like the Scheldt are rich in benthic life. Primary producers like diatoms can form thick algal mats in these areas, which is in turn an important food source for secondary producers like benthic macroinvertebrates. Benthic macroinvertebrates in the Scheldt estuary mainly involve polychaetes, molluscs and crustaceans. In turn, these macroinvertebrates are the key food source for many fish and bird species.
Research questions
- How does the colonization process of benthic macrofauna develop in the de-poldered area?
- Does the remaining vegetation affects the colonization process?
- What is the influence of the elevation gradient on the colonization process?
- Is the colonization process depended on or related to the vertical sediment accretion rate?
- If in the area zones arise with standing water (no channels), what is the impact on the colonization process?
- Are benthic communities in Perkpolder similar to benthic communities in similar ecotopes in the Western Scheldt?
- How will vegetation establishment affect the benthic macrofauna and vice versa (interactions)?
- How does the development of Perkpolder compare to the development of Rammegors in the Eastern Scheldt? What can be learned about the design of de-polders areas?
- How is the Perkpolder area used by birds?
- Has the area a foraging function for water birds?
- Will the area be used by birds as a high water roost?
- Will the area in the future be used as a breeding area for waterfowl or marsh birds?
Data and methods
The data and the methods that have been used for the evaluation of the benthos and bird development are all described in the Perkpolder progress reports:
Referenties
- Perkpolder tidal restauration, one year after realisation, draft progress report, Boersema, M., J. van der werf, P. de Louw, T. Ysebaert, T. Bouma, Centre of expertise Delta Technology, 27 november 2016.
Zie ook
- Perkpolder tidal restauration, one year after realisation, draft progress report
- Rammegors tidal restauration, final report
- Perkpolder Tidal Restauration
- Development of the benthic macrofauna community after tidal restoration at Rammegors
- Building with Nature; from concepts to practice
- Oesterdam sand nourishment - ecological and morphological development of a local sand nourishment
- The Benthic Ecosystem Quality Index (BEQI), intercalibration and assessment of Dutch coastal and transitional waters for the Water Framework Directive. Final report
- Wadden Sea Plan 2010
- Oyster reefs and coastal protection
- The conservation of eroding intertidal flats through nourishments: Ecological development on the Oesterdam tidal flat (Oosterschelde, the Netherlands)
