Hay meadow communities in western Norway and relations between vegetation and environmental factors

Plant species of 79 hay meadow sites in Ytre Sogn and Sunnfjord, western Norway, were recorded and the environmental variables oceanity, slope, exposure, moisture, pH, soil organic matter, quantity of fertilizer used, and cutting and grazing management regime were measured or estimated. Constrained ordination by canonical correspondence analysis (CCA) indicated that moisture, oceanity, the quantity of fertilizer (NKP) and management were important environmental factors in influencing the floristic composition of the meadows. Moist meadows had higher pH and higher loss‐on‐ignition than drier ones. In this data set boreal meadows tended to be steeper and more heavily fertilized than oceanic ones. Classification using TWIN‐SPAN resulted in 7 units along the two main gradients of moisture and oceanity. Four of the units belonged to the oceanic hay‐meadow association Cardamino pratensis ‐Conopodietum majoris. One unit comprised meadows characterized by suboceanic species. Two units were boreal in distribution, both comprising releves from rather moist and well fertilized sites. A key to 8 communities is proposed, together with a short description, based on the present and earlier data.