Soil temperature variation in calciphile mountain plant communities in Southern Norway

Abstract

Soil temperature dynamics are considered to be of great importance for alpine plant life. The aim of this study was to analyse differences in soil temperature parameters between and within exposed ridges, leesides, and snowbeds during one year. The study was performed in two mountain areas, north and south of the Hardangervidda mountain plateau (Norway). Data loggers recorded soil temperatures 5-10 cm below surface, twice daily in 60 study plots, stratified to calciphile vegetation. In each plot, species abundances were estimated in percentage ground cover, and snowmelt was monitored. TWINSPAN classification was used to separate small-scale vegetation groups. Relationships between these small-scale vegetation groups and soil temperature parameters were tested by Detrended Correspondance Analysis, Principal Component Analyses, and Canonical Variates Analyses. The results demonstrate that the annual variation in soil temperatures not only differed significantly between exposed ridges, leesides, and snowbeds, but also between the small-scale vegetation groups. Plant species composition was highly correlated with soil temperature variables. To distinguish between small-scale vegetation groups, soil temperature conditions during the snowmelt period were most important, followed by growing season and winter soil temperatures. The winter half-year is also predicted to be most affected by future climate change in Norwegian mountains.