Nederlandse kustduinen : geobotanie

The Dutch coastal dunes carry a rich and varied flora. This richness is dependent on the local mosaic of habitats. Dune slacks are the major type of habitat and the most threatened in the Dutch dune belt. The influence of groundwater on dune slack vegetation is illustrated. The vegetation of dunes, especially of slacks, has been described by lists of species and vegetation maps in earlier publications. An explanation of methods used in such surveys, including floristic surveys and mapping of vegetation, is given. Comparison with historic records showed that slack vegetation deteriorated severely between 1850 and 1978. A fall in watertable was the main cause of the deterioration in vegetation of dune slacks near Bergen (NorthHolland). Studies there and elsewhere along the dune belt showed that even a small fall in watertable could cause considerable changes in vegetation, such as a fall in the number of phreatophytes.