Modelling the effect of changing snow cover regimes on alpine plant species distribution in Alpine context

Snow cover is a critical parameter for the dis tribution of plant species in alpine re- gions. Earlier snow melt and an elongation and/or shift of the snow-free period - as a result of increas- ing summer temperatures observed since the 1990's - might hence severely alter the spatial pattern of suitable habitats for many alpine plants. Here, we use two spatially-explicit and physically-based snow distribution models (PREVAH and SnowModel) to develop various snow cover maps (SCMs) at a 20m resolution for a high mountain landscape in Austria. We use four different mountain ranges in the North-eastern Calcareous Alps (Mt. Hochschwab, Mt. Rax, Mt. Schneealpe and Mt. Schneeberg; overall area of about 150 km 2 ). SCMs will first be evaluated with SPOT-HRVIR images. After success- ful evaluation, accordant SCMs will be simulated under various scenarios of temperature, precipitation and wind regime changes for the middle and the end of the 21 st century (A2 IPCC scenario). These SCMs are finally used as additional predictor variables in species distribution models (SDMs) to as- sess potential modification in the area and connectivity of the habitats of a set of alpine plants, in par- ticular those confined to sites with long-lasting snow cover ("snowbeds"). The main parameters ana- lyzed are the timing and duration of the snow period to provide spatial projection of species distribution under current and future climate conditions. SDMs results indicate that changes on snowbeds species may be buffered (2050's) but then could become stronger at the end of the century.