Keywords:
onshore barrier dune
grazing by domestic livestock
vegetation development
dune-grassland
Contact: H.G.J.M. van der Hagen. Dune Water Company
of South Holland. Office of Nature and Landscape Conservation.
P.O. Box 34. 2270 AA Voorburg. The Netherlands.
Location: The Netherlands, North Sea, The Hague
The Meijendel dunes, The Hague
Meijendel is a coastal sand dune system of calcareous origin bordering
the North Sea. It is situated north of the city of The Hague and
has been used as a catchment area for drinking water by the DZH
(Dune Water Company of the province of South Holland) for approximately
125 years. The total area covers approximately 2000 ha with an
average width of 3200 m, and consists of barrier dunes with a
zonation from yellow to grey dunes. Although Meijendel is situated
in the most densely populated and industrialized part of the Netherlands,
it is still free from such influences. The area contains a diverse
plant and animal species composition, it is the fourth most important
bird area in the Netherlands.
Management
Since the 1950s, the species-rich dune grassland, of which are
several in the priority list of the EU habitat guidlines, appendix
I, has gradually declined. This is mainly due to atmospheric nitrogen
deposition, planting of marram grass and decreased intensity of
grazing by rabbits, as a result of the myxomatosis plague in 1956.
Because of that, in 1990 extensive grazing by horses and cows
was introduced by the DZH in two parts (123 and 273 ha) in Meijendel,
both situated between the fore-dunes and the inner dunes.
In 1995, the DZH partly in cooperation with the Wageningen Agricultural
University launched a research programme to compare ungrazed and
grazed parts of the Meijendel dunes, in respect to vegetation
development.
Results
The observation concluded, that grazing causes a decrease of dominant
species, which leads to a slight shift in species composition,
but only on the level below the association. Grazing also causes
a change in the vegetation pattern from coarse-grained to fine-grained.
It is a suitable way of enhancing species-richness in dune grasslands
by opening the grassland canopy and the top soil, which is important
for the development of various groups of animals, too. Extensive
grazing is an excellent management tool in nature conservation
and can, instead of other methods such as cutting sods and burning
and mowing, easily take place on steep dune slopes and guarantees
a more natural and gradual border between the various vegetation
types. In fact, it may be seen as a reintroduction of former management,
since extensive grazing was common in the dunes until the beginning
of this century. In 2001 an evaluation about the 10-years grazing
experience in the area will be carried out.
Because of the ‘grass encroachment’ in several species-rich, relatively
open grasslands in the coastal dunes in the Netherlands, numerous
studies have been carried out in the past about introducing grazing.
For example, a study about grazing with sheep took place in Zwanenwater
from 1984-1992, a nature reserve located northwest of Amsterdam.
It was pointed out, that grazing has a positive effect on the
persistence of open grassland communities. Within the open communities
the number of species increased because of grazing, whereas vegetation
height decreased as well as vegetation cover and the thickness
of soil organic horizons. The effect was intensified by a longer
treatment.
Grazing in Meijendel; the areas Kijfhoek/Bierlap and Helmduinen
References
- de Bonte, A.J., A. Boosten, H.G.J.M. van der Hagen &
K.V. Sýkora (1999): Vegetation development influenced
by grazing in the coastal dunes near The Hague, The Netherland.
Journal of Coastal Conservation 5: 59-68. EUCC. Opulus Press
Uppsala. Sweden. (KJc99).
- Kooijman, A.M. & M.W.A. de Haan (1995): Grazing as a
measure against grass encroachment in Dutch dry dune grassland:
effects on vegetation and soil. Journal of Coastal Conservation
1: 127-134. EUCC. Opulus Press Uppsala. Sweden. (KJc95).
- ten Harkel, M. (1998): Nutrient pools and fluxes in dry coastal
dune grasslands. Thesis. Amsterdam. (33R4BNd98).
- van der Hagen, H.G.J.M. (1997): Paarden en koeien in Meijendel.
Holland’s Duinen 31: 31-44. (33.9.4).
- van der Meulen, F. & E. van der Maarel (1993): Dry coastal
ecosystems of the central and southwestern Netherlands. In:
van der Maarel (ed.). Ecosystems of the world 2A. 271-306. Elsevier.
Amsterdam-London-New York-Tokyo. (BN93).
- van Dijk, H.W.J. (1992): Grazing domestic livestock in Dutch
coastal dunes: Experiments, experiences and perspectives. In:
Carter, Curtis & Sheehy-Skeffington (eds.). Coastal Dunes:
273-281. Balkema. Rotterdam. (BNd92).
