* Fixed coastal dunes with herbaceous vegetation (grey dunes)
Fixed dunes, mostly dominated by grasses (Poales), free from or poor in woody plants, showing an onset of humus accumulation in the soil, located on the landward side of the marram (white) dunes along the Atlantic, North Sea and Baltic coasts.
Apart from containing species-rich stands of the Koelerion albescentis (class of sandy dry grasslands), the Corynephorion (alliance of Grey hair-grass communities) and Thero-Airion (alliance of ephemeral-rich Aira swards) they are rich in cryptogams (moss and lichen carpets in places). Occasionally the vegetation is transitional in character to semi-dry grassland communities of the Mesobromion and to saum communities of the Trifolio-Geranietea. The lime content varies with the substrate and with the gradual transition to fixed dunes the substrate becomes increasingly decalcified.
Notes on habitat mapping
The essential criterion for the delimitation of this habitat type is the presence of vegetation on coastal dunes of the syntaxa given above. Larger sandy plains or stands which are no longer subject to coastal influences are excluded. Smaller level sites in between dune complexes and smaller areas free of vegetation are included. Stands on Geest (North Sea) or moraine substrate (Baltic) are not considered grey dunes. Also, grey dunes dominated by woody plants such as heaths, scrub, precursors to woodlands, or woodlands should not be considered under this habitat type. They should be recorded separately as decalcified fixed dunes with Empetrum nigrum (2140), Atlantic decalcified fixed dunes (Calluno-Ulicetea, 2150) or coastal dunes with Hippophaë rhamnoides (2160), coastal dunes with Salix arenaria (2170) or wooded coastal dunes (2180).They can be differentiated from humid dune slacks (2190) by their lack of moisture indicating plants.