Habitat preferences of some red-listed alpine plants in Scandinavia

Scandinavian alpine vascular plants are red-listed (R-L) according to criteria defined by IUCN. These are based on an evaluation of their risk for extinction in the future, which for most alpine plants have been related to possible effects of climate change. In the present study, ecological characteristics of R-L alpine plants are inferred from their occurrence in previously studied alpine plant communities. In total, data on 231 communities were compiled from studies in Norway and Sweden, and a total of 39 red-listed vascular plants were found in 142 of them. The data were analysed by numerical analyses in order to assess if and how communities with and without R-L species differ in terms of floristic composition and environmental conditions. The analysies show that most of the R-L plants are situated at the ends of the main floristic gradients extracted by Detrended Correspondense Analysis (DCA). These extremes are interpreted to represent high-altitudinal communities with long-lasting snow cover. In productive communities dominated with herbs and ferns, R-L plants are few or missing. A Principal Components Analysis (PCA) indicated that the R-L species form a heterogeneous group both in terms of ecology, abundance, and geographic distribution. Some of the communities were considered to be especially valuable because they included several (up to eight) R-L plants. Such communities are found in the upper part of the middle alpine or high alpine zone (460–675 m above the forest limit) and on calcareous substrate. It may generally be assumed that alpine plants with optima at the edges of the floristic gradients may be especially vulnerable to climate changes.