Brackish marshes, limited in surface, with very specific abiotic requirements, are one of the most threatened habitats in Flanders. These very dynamic systems are mainly situated in and near, and frequently conflict with the interests of, the Flemish ports.
Because of the planned construction of a tunnel under the Scheldt, numerous hectares of this valuable habitat are threatened. Sinking the tunnel will require the excavation of these tidal mudflats and brackish marshes. However, since the construction is limited in time and the habitats will be reconstructed, the question about (re)colonisation arises. In other words, what are the steering factors behind the different colonisation patterns and how can these be translated into ecosystem functioning.
To answer these questions, colonisation is divided into three facets:
1. Seed dynamics 2. Germination and growth dynamics 3. Senescence dynamics
The existing seed bank in the soil (after theconstruction of the new tidal mudflats) and the seeds that are being transported by the Scheldt (season and tidal effects) will be analysed and compared with the actual colonisation in the field. The project area will be digitally recorded along sixtrajectories every two weeks, perpendicular to the Scheldt, along a gradient of flooding frequence/duration/depth. The observed germination and senescence dynamics will be supported with an experimental set-up where substrate, dynamics and frequency effects can be analysed.