* Species-rich Nardus grasslands, on siliceous substrates in mountain areas (and submountain areas in Continental Europe)
Closed, dry or mesophile, mat-grass swards occupying siliceous soils in the upper ranges of the Hercynic mountains, the Alps and the Pyrenees (Eu-Nardion), as well as mat-grass swards of lower altitudes (planar to submontane: Violo-Nardion). Species-rich sites should be intrepreted as sites with a high number of species while habitats which have become irreversibly degraded through overgrazing should be excluded.
Pursuant to the agreement reached at the first assessment seminar for the Atlantic biogeographical region (Kilkee, 1999) this habitat type also includes lowland mat-grass swards (planar to submontane).
Notes on habitat mapping
The criterion for delimitation of this habitat type is the presence of vegetation of the syntaxa given above in planar to high montane zones. Subalpine natural mat-grass swards of the Alps are included in the habitat type Siliceous alpine and boreal grasslands (6150).
Species-poor examples which can arise, for example, as a result of overgrazing or long-term abandonment are excluded. In such cases it is not the absolute number of species which is decisive for the evaluation of the sward, but the combination of species as compared to typical facies of the same syntaxon in a regional context. Species which are alien to the syntaxonomic unit should not be considered as adding to species-richness.