Description

habitat

General occurrence

This priority habitat type includes fixed dunes, stabilised and colonised by more or less closed perennial grasslands and abundant carpets of lichens and mosses, from the Atlantic coasts (and the English Channel) between the Straits of Gibraltar and Cap Blanc Nez, and the shores of the North Sea and the Baltic. These so-called "grey dune" are located more land inward than the "white dunes" covered with European Marram grass (habitat type H2120). This habitat type includes various species of dune grasslands of the class dry and calcareous dune grasslands (Polygalo-Koelerion), Syntrichia association (Tortulo-Koelerion), Common bent association (Plantagini-Festucion), Dune- grey hair-grass association (Corynephorion canescentis) and species-rich Nardus grasslands (Nardo-Galion saxatilis). In The Netherlands, this habitat type occurs in all coastal dunes, from Schiermonnikoog to the Zwin. Some of these communities are very special, as they only occur in The Netherlands and include a large number of rare species. This specifically concerns the grassy dunes with dandelions, communities of the so-called seavillage landscape and communities of lime-poor old dunes. Because of air pollution, reduction of dynamics and a sharp decline in rabbit population, this habitat type is threatened with extinction on many locations, as grasses or brushwood becomes the dominating vegetation. The landscape of seavillages is well-developed in the calcareous Dutch dunes near old fishing villages such as Scheveningen, Katdijk, Noordwijk, Wijk aan Zee and Egmond. Grassy dunes with dandelions mostly occur on calcareous dunes south of Bergen. Old dunes are mostly found on Goeree and Schouwen #1.

Environmental boundary conditions

Small scale human influences are characteristic for a sea village landscape, such as treading and grazing, and in the past also the fixing and drying of nets, bleaching of linen and growing potatoes. This kind of landuse has led to local sand-drifts and a larger variety of food, resulting in a strong variety of habitats within a short distance. Noticeable species of this landscape type are Sand catchfly (Silene conica), Nottingham catchfly (Silene nutans), Spanish catchfly (Silene otites), Field sagewort (Artemisia campestris subsp. maritima), Spring millet Grass (Milium vernale), Pyramidal orchid (Anacamptis pyramidalis) and Yarrow broomrape) (Orobanche purpurea). Grassy dunes with dandelions are probably the most characteristic for grey dunes. These grasslands need a calcareous habitat. Grasslands are conserved by slight sand-drifts, rabbit grazing and grazing by cattle or horses. Besides a number of specific dandelions, the following characteristic species occur: Teesdale violet (Viola rupestris) and Star gentian (Gentiana cruciata). In dune areas with stable rabbit populations, the grassy dunes with dandelions are mostly well preserved. However, if the rabbit populations diminish, there is a threat of becoming overgrown with grasses such as Wood small-reed (Calamagrostis epigejos) or Creeping willow (Salix repens). Old dunes can be found on locations near old dunes that used to be grazed, the so-called common land. The present grasslands have best developed on places where the old dunes have kept their original, slightly fluctuating relief. Here, endangered species such as Autumn lady's-tresses (Spiranthes spiralis) and Field gentian (Gentianella campestris) occur.

Control and growth opportunities

Grazing and treading are important factors for maintaining this habitat type, as it prevents grasses and brushwood to become the dominating vegetation. Deterioration of this type is mainly caused by air pollution, reducing of dynamics and a sharp decline in rabbit population #1.

Dose-effect relations

These dose-effect relations have been based on habitat factors of occurring plant communities. The habitat type itself is a landscape characteristic and therefore it is difficult to define relations.

Flowchart

General dose-effect relations

Reference: #1