Full text: Proceedings of the Symposium on Global and Environmental Monitoring (Pt. 1)

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LANDSCAPE SUCCESSION IN A DUTCH DUNE AREA 
L.H.W.T. Geelen 
Municipal Waterworks Amsterdam 
Vogelenzangseweg 21 
2114 BA Vogelenzang 
The Netherlands 
ABSTRACT 
In a case study in the Amsterdam Waterwork Dunes, The Netherlands the landscape succession 
has been analysed by means of aerial photographs of 1938,1958,1968, 1979 and 1985. In 1985 
field studies were carried out to check the later analysis. 
In the thirties and fourties of this century, the vegetation structure was mainly open (dry 
dune grasslands). Since the mid-fifties this dominating open vegetation has been more and 
more encroached by variable patterns of open low shrub. During the last decennia the diver 
sity in vegetation structures increased by the local development of open low shrub into 
more dense and/or taller shrub vegetation. During the last 50 years the coverage of the 
treelayer increased proportionally by the development of small deciduous woodlands and the 
planting of pine forest. 
A great number of factors is affecting vegetation structure development: (meso)climate, 
relief, hydrology, soil, fauna and man. In the study area hydrology has been of special 
importance. Dunewater catchment has led to a significant lowering of the groundwater table 
during the first half of this century. Later on, it raised again as a result of changed 
hydrological management. 
Grazing has also been of great influence , especially the termination of cattle- and 
sheepgrazing in 1920. Moreover the sudden decrease of rabbit grazing,as a result of myxoma 
tosis disease since 1954, has favoured the growth of woody species. If this shrub vegeta 
tion continues to increase,probably the present-day management of "doing nothing" has to be 
changed, to prevent further loss of the diversity of vegetation structures. Maybe stock 
grazing and/or the development of blowouts can be used as managment tools to retard succes 
sion and reintroduce the characteristic young dune phases. 
KEY-WORDS : dune landscape, aerial photographs, vegetation structure, succession. 
1 INTRODUCTION 
The Municipal Waterworks of Amsterdam are 
catching drinking water in a part of the 
Dutch coastal dunes; the so called Amster 
dam Waterwork Dunes (AWD) (fig.l). These 
dunes are also important for coastal defen 
ce, nature conservation and recreation. 
The Municipal Waterworks only recently 
considered nature conservation to be one of 
their tasks. This explains the lack of 
historical field data. There are no vegeta 
tion maps before 1980. 
To develop an adequate dune management 
however, insight is required in the changes 
of landscape, vegetation, hydrology and so 
on. This is very difficult when no field 
data are available. Thanks to the impor 
tance of the dune area for sea- and mili 
tary defence, old stereoscopic aerial pho 
tographes were available of 1938, 1958, 
1968, 1979 and 1985. 
The next two questions will be tackled: 
1) HOW CAN CHANGES IN LANDSCAPE AND VEGETA 
TION BE TRACED BY THESE PHOTOGRAPHS ? 2 
2) DO THE AERIAL PHOTOGRAPHS GIVE SUFFI 
CIENT INFORMATION TO DEVELOP AN ADEQUATE 
DUNE MANAGEMENT ? 
2 INVESTIGATION AREA 
To answer these questions a case study was 
started (Ehrenburg & Geelen, 1986). The 
study site (176 ha) is imbedded in the 
Amsterdam Waterwork Dunes. The distance to 
the North Sea is about 800-1800 meters. The 
origin of this location goes back to the 
13-15th century. In this period sand drift 
must have formed, mostly, this younger grey 
dune landscape, as we can recognize it 
nowadays.The area is characterized by se 
condary parabolic dune systems. Seaward 
younger landscapes can be recognized , 
whereas the inner dunes are much older. 
fig. 1 The location of the study area. 
Amsterdam, hatched= coastal dunes. 
1= 
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