Geobotanische studie van de Berger duinen
1926
Bijhouwer, J.T.P.
The area studied was between Egmond and Schoorl (12 km2; 6 km long). Plant associations were described by estimate and by combining the mapsquare method of Clements and the method of Raunkiaer. The dune area was divided into 7 parts, different in vegetation. Towards the south the density of the vegetation and the number of species increased. In each part 7 or 8 plant associations could be distinguished with different watertables. Plant species of only local occurrence were grouped into: A. Northern plants; B. Plants very near the sea; C. Plants of waste places (such as verges); D. Southern plants. The A and D species were calcifuges and calciphils, respectively. The B species were true halophytes, the C and some of the D species were nitrophils.Lime status and pH of soil were closely correlated. The dunes of Bergen were the most acid ones of the Netherlands and differ from the old inner dunes. The lack of some plants and animals on the Friesian islands suggests the former existence of a large post-glacial river between Egmond and Texel. So the dune sands of Bergen are fluvial.
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