The effects of dissolved macro-nutrients on the herbaceous vegetation around dune pools

Abstract

In Dutch coastal dunes the relation was studied between the composition of the vegetation on the banks of pools and the nutrients supplied by the groundwater. Areas infiltrated with eutrophic river water were compared with non-affected areas. The floristic composition was interpreted according to classification systems of ruderal, ‘nitrophilous’ tall hemicryptophytes and the conservation parameters richness and rarity. Of the three main macro-nutrients (orthophosphate, nitrate and potassium), the orthophosphate load shows the highest correlation with the vegetation variables. It is suggested that a reduction of orthophosphate during pre-purification of the infiltration water would reduce the dominance of the ruderals to the extent that the original dune slack species could return locally.