Introduction

Many regions of the dunes along the coast of The Netherlands are now in use as part of the drinking water supply chain and are therefore well protected. The Amsterdam Waterworks Dunes, situated south and west of Haarlem, deliver drinking water to the city of Amsterdam. The site is owned and managed by the municipality of Amsterdam. In this dune field of 34 km2 the mycota of two, locally decalcified, natural grasslands has been studied since 1986 (Becker & Baeyens, 1992; Nauta & Jalink, 1996). The management consists of summer grazing by cattle in one site (Eiland van Rolvers), and yearly mowing and removal of the hay in the other (Groot Zwarteveld).

History

The area of the Amsterdam Waterworks Dunes consists mainly of young dunes, formed during several periods of blowing sand from the eleventh century onwards. The soils differ in calcium content, depending on the period in which they were formed, and this can often be seen from the vegetation. For instance, the Hippophae rhamnoides scrub, developed in the central part of the Amsterdam Waterworks Dunes from around 1500–1600 onwards, has usually developed on more or less calcareous soil. From early days humans have used the dunes. There is evidence that from 1500 onwards, wet dune slacks have been grazed in summer by cattle and sheep.

In the early nineteenth century the dune area also became popular for growing potatoes.