1 Introduction Nardus grasslands are low-productive, unfertilised, extensively managed grassland communities that were once widespread across much of western and central Europe on nutrient-poor, acidic soils (pH ≤ 5.5; Peppler-Lisbach and Petersen 2001). The wide altitudinal gradient along which they occur, ranging from sea level up to 2500 m in the Alps, is the main factor contributing to their floristic variability (Krahulec 1985; Peppler 1992).