Waternet is responsible for the provision of water-related services for Amsterdam and the surroundings. Among its main responsibilities is the management of the Amsterdam Watersupply Dunes (AWD), a 3 400 ha nature site, owned by the municipality of Amsterdam, and part of the Natura 2000 network of sites. The main land use is nature conservation and drinking water supply. Every year up to 800 000 people visit the site for walking and hiking.
Since 1850, the area’s valuable, characteristic dune/ wetland habitat types had deteriorated both in size and quality due to desiccation (drying out) from water extraction, air pollution and acidification and eutrophication (nitrogen deposition). In recent decades this problem had decreased, due to changing the method of water production in the area and measurements to reduce the nitrogen deposition. Since 1990, conservation measurements and further large-scale projects had been carried out by Waternet, to restore the natural dune systems and wetland habitat types. However, large-scale restoration measurements were required in order to reverse the effects of long term dehydration, eutrophication and encroachment of the invasive alien species, black cherry (Prunus serotina) in order to create the right conditions for the restoration of the natural habitats.
The overall aim of the Amsterdam Dune project was to restore and improve the characteristic and priority habitat types of the Natura 2000 network site, Kennemerland-Zuid, located to the west of Amsterdam. The area’s recovery was encouraged by actions targeting the effects of drying out and eutrophication, such as the removal of the nitrogen-rich top layer of soil and of invasive species, restoration of ponds; and by mowing, grazing, and other nature management measures.
Specific project goals were:
All the planned actions of the Amsterdam Dune project were successfully completed during the project. The project met its objectives, while at the same time, the beneficiary gained valuable experience on how to organise large scale restoration actions. The ecological monitoring results showed that, despite the short time since the measures were carried out, the recovery of priority habitat types, ‘grey dunes’ had started. ‘Dunes with Hippophae rhamnoides’ also appeared to recover, but only locally. In a relatively short timescale, sixty three ponds were restored, after dredging and removal of mud bank vegetation, and the initial developments concerning 'humid dune slacks’ were similarly, fairly positive by project end. Nevertheless, the existing fallow deer population posed a threat to the restored dunes, due to over grazing. A Fallow Deer Management Plan was developed to address this issue.
In terms of policy, the project contributed directly to the implementation of the EU Birds and Habitats Directive, the EU Biodiversity Strategy to 2020, the EU strategy on invasive species and national policy concerning Natura 2000 site management.
Other results included removal of a larger than expected area (169.15 ha) of scrub and woodlands, including the invasive alien species, black cherry (Prunus serotina) which had spread more extensively than expected, between the time of the project application and implementation. This resulted in the need to remove more than initially planned for and thus, higher costs. In the future, the beneficiary has pledged to closely monitor development of the invasive black cherry and other IAS (Invasive Alien Species) and to carry out measures to combat its development, as early as possible to reduce the amount of required remedial work. Interestingly, the project showed it was possible to combat the invasive species, without the use of any chemical.
Monitoring showed that, despite the short time since the project’s measures were carried out, recovery of priority habitat type, ‘grey dunes’ had started. However, in the areas where mowing was the main or sole activity carried out, the LIFE team observed that there were still a number of species adversely affected by encroachment. Therefore, it was decided that extra maintenance (provided for in the project’s After-LIFE plan) would be required, in order to guarantee a durable result.
Concerning the ‘humid dune slacks’, while the early results were positive, the beneficiary cautioned that the supply of sufficient base-rich groundwater with seepage and sufficient dispersion of the targeted species from the surrounding area might prove to be a problem for full restoration of this habitat type. Also, although only recently restored, the ponds have started to show some promising results. For instance, the establishment of stonewort (Characeae), and return of amphibians (e.g. the natterjack toad) and dragonflies (e.g. yellow-spotted whiteface).
Finally, based on the measures carried out and the initial monitoring results, the project forecast the following, expected habitat developments for the medium term:
Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).