Invloeden van oppervlakte-infiltratie ten behoeve van duinwaterwinning op kruidachtige oevervegetaties

Many Dutch coastal dune areas have been infiltrated artificially for public water supply purposes. This infiltration of eutrophic water fosters the occurrence of nitrophilous tall hemicryptophytes in phreatophytic vegetations. The rich and diverse indigenous vegetations of w wet dune slacks have almost completely disappeared from the infiltrated dune areas.This thesis describes investigations into the relation between the vegetation on the banks of natural and artificial dune pools and lakes and the available quantities of macro-nutrients These studies were carried out both in infiltrated and in non-infiltrated dune areas.The vegetation has been analysed by using various ecological parameters. Among the three main macro-nutrients (phosphate, nitrate and potassium), the supply of phosphate due to flowing ground water shows a very significant and probably causal relation with the applied vegetation parameters. In non-infiltrated areas, the supply of macro-nutrients due to mineralization of organic matter appears to dominate the supply due to flowing ground water