These dunes were formed from the remains of the old Wadden island of Huisduinen. South of this lie the Donkere Duinen (Dark Dunes). These originated from the small Wadden island of Ooghduinen. In the 16th century, the gap between the two islands closed up. The small dune lake Harmplas now lies on this spot.
The Donkere Duinen is a planted pine forest that is being transformed into a diverse, more natural one. There is a circular duck pond with bushy banks. The Donkere Duinen can get quite busy, as it's the only walking forest near Den Helder.
The Refugium is a seven-hectare area created through nature development. It sits like a wedge between the development of Nieuw Den Helder, the Grafelijkheidsduinen, and the Donkere Duinen. It was created when sports fields were transformed into new natural areas. Now it's a true paradise for unique plants.
The Grafelijkheidsduinen and the Refugium are grazed by Scottish Highlanders. A few Konik horses also help out in the Grafelijkheidsduinen. Grazing in these areas promotes diverse vegetation. In some areas, the vegetation is kept short and the soil lean, while in areas where a lot of manure is applied, plants that prefer nutrient-rich soil can grow.
