A synecological investigation of Athyrium distentifolium‐dominated stands in Western Norway

Abstract

This paper presents results of a study on the synecology of Athyrium distentifolium. The investigation is based on phytosociological and ecological analyses of stands dominated by A. distentifolium within its whole distributional area in Western Norway. The distribution and floristic composition of the stands are related to different environmental parameters such as climate, soil and topography. The data are analysed by numerical methods, of which two‐way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. Based on a TWINSPAN classification of the 211 investigated stands, 9 different groups (types) are distinguished. These belong mainly to three phytosociological alliances: Cryptogrammo‐Athyrion alpestris (1 group), Lactucion alpinae (5 groups) and Vaccinio‐Piceion (3 groups). The quadrats are in most cases very poor in species, even in edaphically rich areas. Soil richness in the stands is very variable. A. distentifolium may be dominant in edaphically rich areas and it is not a calciphobe species in W. Norway. Most stands show no signs of human influence. Length of snow‐lie is assumed to be of major importance for the development and distribution of A. distentifolium stands.