Coastal dune grasslands, dune heathlands and dune slacks are threatened or vulnerable habitats all across Europe. In the Netherlands, the dunes’ biodiversity is decreasing, mainly due to eutrophication and desiccation. The Dutch dunes are of European importance as they comprise 10% of all European dunes, and are among the best preserved in the northwest of Europe. The State Forestry Service manages around 15 000 ha of dunes, roughly a third of the total area. Eight Natura 2000 sites, partly managed by the State Forestry Service, are included in this project. The priority types of dunes, ‘the fixed grey’ and the ‘decalcified fixed dunes with Empetrum nigrum’, are two of the dominant habitat types in the project site area.
The main objective of this project was to create favourable conservation conditions through a set of related measures carried out on 4 700 ha of dunes covering eight Natura 2000 sites. The project focused on restoration of around 1 100 ha of wet and humid dune areas, primarily through restoration of natural hydrology, sod cutting and the removal of shrubs. It also aimed to restore dune grasslands and heathlands on around 1 550 ha through grazing, preceded by the removal of non-indigenous forest and/or scrub, favouring the two priority dune types: ‘fixed grey dunes’ and ‘decalcified fixed dunes with Empetrum nigrum’. Furthermore, the project would create favourable conditions for embryonic dunes and shifting dunes with Ammophila arenaria on 10 to 20 ha. Finally, it aimed to replace coniferous plantation with natural woodland on an area of around 40 ha.
The Dutch Coastal Dunes project carried out various measures to restore the dynamics and openness of our dunes. On the islands of Texel, Terschelling, at Hollands Duin and the Kop van Schouwen, trees and bushes were removed from wet dune slacks to create more space for young vegetation and to introduce more openness and variation to the landscape.
Alongside tackling the dense vegetation in the dune valleys, the project in also worked to improve soil hydrology. The exceptional plants that characterise the dune valleys thrive in damp conditions. Various valleys have been re-wetted by filling in ditches or rerouting them.
Nutrient-rich topsoil was removed from various dune valleys at all the project sites. Topsoil is the top 10 to 15 cm of black earth where most of the nutrients plants need are located. Trees, shrubs and grass grow well in a nutrient-rich soil, but overgrow the plants, such as bog stars and rare orchids, which need nutrient-poor conditions. The seeds of these plants are often still to be found in the subsoil’s seedbank. Removing the topsoil allows these seeds to germinate.
To ensure that the dunes remain open after all these activities, livestock grazing is being encouraged in various locations at all the project sites. Goats, sheep, ponies and cattle ensure that young trees do not gain a foothold. Furthermore, the livestock trample the soil which leads to more open spaces and variation in the dunes. In some places this can even restart the aeolian movement of sand. Thanks to new gates and fencing, the livestock stays in the designated areas and visitors can enter and leave.
By restoring the natural dynamic of the dune, the wind, sand and sea can recommence their natural effects. Desiccated dunes have been re-wet and the management of areas using grazing has been expanded. Restoring the dunes’ natural variation benefits animal and plant species.
While the dunes are still in an early stage of recovery, the initial signs provide hope. On Texel, wet and moist pioneer communities (Littorellion uniflorae and Nanocyperion flavescentis) were observed on areas exhibiting the first restoration phases of species-rich dune slacks. During the monitoring study of wet dune slacks on Terschelling 15 IUCN Red List species were observed, of which some were numerous: shoreweed, round-leaved sundew, bog myrtle, allseed, lesser water-plantain and yellow centaury.
On Vlieland, in rehydrated valleys, black bogrush and early marsh orchid were observed for the first time in decades, while on Ameland it is still to early to assess the effects of the project. Locally characteristic species such as bog stars, seaside centaury and brookweed were seen in the mainland dunes near Noordwijk and Wassenaar. At the Vroongronden on Schouwen, the characteristic vegetation of open water or valleys that dry out over the summer prove to be responding positively to the measures implemented: in 2011, 16 Red List species were observed. Before the interventions, a number of these plant species had disappeared in these locations.
The project results can be summarised as follows:
Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).