Responses of alpine vascular plants and lichens to soil temperatures

Plant abundance and distribution patterns have mostly been explained in terms of air temperatures, yet a great deal of vascular plant biomass is located below ground. Winter soil temperatures, which are related to both air temperature and snow cover, may therefore be important determinants of species composition in alpine areas. Epigeic lichens, however, have no underground biomass, and they often dominate at sites that are inhospitable to vascular plants, such as those that experience sustained periods of sub-freezing temperatures. In this study, effects of several warm-and cold-season soil-temperature variables on individual plant and lichen species common to oligotrophic alpine heaths was investigated using linear regression and ordination. The differences in growing season length as measured by soil temperatures were compared. Warm season variables were found to have less influence than cold season variables on individual species abundances in these areas. Changes in winter snow cover depth and duration, such as those that are predicted in Norway, can result in changes to soil temperature patterns, to the possible benefit of some species and detriment of others.