Temperatures in the Life Zones of the Tyrolean Alps

Abstract

The bioclimatic temperatures that mountain plants experience are very different from the macroclimatic temperatures and vary according to the exposition, relief, and growth form. This is shown in the example of boundary layer temperatures recorded in the Tyrolean Alps between the timberline and the nival zone over several years. Microsite temperatures were compared to the air temperatures provided by meteorological stations of the official weather service nearby. In winter plant temperatures below the snow are largely uncoupled from the free air temperatures. During the growing season, across all zones, plant temperatures diverge to differing degrees from free air temperatures depending on the growth form of plants and the canopy structure. In Vaccinietum communities and in closed grassland, average temperature differences between the free air and plant canopy were 0.5K in July and August. Prostrate mats of the Loiseleuria heath, rosette and cushion plants, however, heat up much more than erect plants during sunny periods, and mean plant temperatures were about 2–3Kwarmer than the free air temperatures. As a result, the adiabatic lapserate for bioclimatic temperatures of the life zones in the Alps does not parallel the adiabatic lapse rate of free air temperatures.