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SUMMARY OF THE PROJECT
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The aim of the project is the conservation and reinforcement of the dutch root vole population (Microtus oeconomus arenicola) by the creation of suitable wetland habitat in and around the Jan Durkspolder. |
Microtus oeconomus does occur in the area but is vulnerable because of the limited size of its population. The aim is to strengthen and develop a healthy core population. The most important action is to change the actual fixed water management into a dynamic system with a higher water levels and with more fluctuations. The significance of a variable water level is that it improves the competitive position of Microtus oeconomus with other vole species, such as the common vole and the field vole.
The project area - the Jan Durkspolder and close surroundings (app. 300 ha) - is part of the National Park 'De Alde Feanen' in the centre of the Province of Friesland. The whole area is devided into three sub areas, each with its own optimal water level management.
On top of the natural seasonal fluctuation in the two lower parts (Jan Durkspolder and the area north of it), a multiyear water level rotation is put into effect. This means that these two sub areas in turns will be managed as marsh for a number of years (dry period) after which they will be inundated for several years (wet period). In the years with low water level marsh plants and willows will germinate on the dry slicks. During wintertime these seedlings will partly be lost again, in spring the remaining may develop further. Most plants will be lost again when the dry period is replaced by the wet period.
By applying the multiyear water level rotation the two sub areas will complement each other continuously. This means that together they will always contain suitable habitat for the dutch root vole and other target species, among which many species of water fowl.
The most important part of the project was the transformation of the water management. Through adjusted and newly dug watercourses, pumping stations, inlets and culverts water can now be moved between and within the sub areas. Two American windmills are used for drainage of the polders with multiyear water level rotation.
The project also involved al lot of excavation work: filling in ditches, constructing micro- relief and canal banks.
The reconstruction of the Jan Durkspolder and close surroundings is first and foremost aimed at its benefits for nature. However, the project has also a big socio-economic relevance. The project area is a very popular site for birdwatching. In this project measures have been taken to offer a varied supply to enjoy this interesting natural environment. Footpaths were made, canoe routes were set up and It Fryske Gea has placed a second birdwatching hut.
The project was carried out in the period October 2005 to December 2006.
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Brochure
Brochure (English)
Brochure (Français)
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