|The nature of nutrient limitation in Dutch dune slacks|
Koerselman, W. (1992). The nature of nutrient limitation in Dutch dune slacks, in: Carter, R.W.G. et al. (Ed.) Coastal dunes: geomorphology, ecology and management for conservation: Proceedings of the 3rd European Dune Congress Galway, Ireland, 17-21 June 1992. pp. 189-199
In: Carter, R.W.G. et al. (Ed.) (1992). Coastal dunes: geomorphology, ecology and management for conservation: Proceedings of the 3rd European Dune Congress Galway, Ireland, 17-21 June 1992. A.A. Balkema [etc.]: Rotterdam. ISBN 90-5410-058-3. 533 pp., more
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Eutrophication is one of the key factors responsible for the demise of nutrient-poor plant communities in the Netherlands. Eutrophication causes an increase in biomass production, and many characteristic dune slack species are out-competed by a few highly productive competitors. This process occurred on a large scale in water catchment areas, where eutrophied river water is artificially recharged in natural dune slacks and man-made excavations, but also outside infiltration areas, where eutrophication is due mainly to high atmospheric N deposition or increased soil mineralization due to lowering of groundwater tables. Currently, attention is focussed on restoration of wet dune slack ecosystems. Projects aim at reducing the availability of major plant nutrients, nitrogen and phosphorus. If conservation goals are to be reached, the key element that regulates plant growth (limiting factor) must be assessed, as reducing N availability requires measures different from those required to reduce P availability. In this paper, a simple tool is proposed that may be used to assess quickly the nutrient that limits plant growth, based on the vegetation N:P ratio. It is argued, that a vegetation N:P ratio > 26 indicates P-limitation, while a N:P ratio < 16 indicates N-limitation. This hypothesis is supported by experimental evidence, but will be further tested in experimental fertilization studies.