The contribution of cold air pooling to the distribution of a rare and endemic plant of the Alps

Background: The topographic complexity typical of alpine landscapes creates a variety of (micro)climatic conditions that may mitigate the effects of a warming climate on alpine plants via such mechanisms as cold air pooling (CAP). Aims: Our primary objectives were to (1) assess whether landscape potential for CAP as a predictor improved species distribution models (SDMs) projections and (2) quantify the impact of CAP on the microclimate experienced by alpine plants compared to the macroclimate. Methods: We selected the Maritime Alps as our study area, located on the French–Italian border, and its rare endemic plant, Saxifraga florulenta, as model taxon. We generated a spatial layer in GIS (Geographic Information System) that reflected the potential of the landscape for CAP and ran five SDM algorithms with and without CAP layer as a predictor. Second, we recorded the microclimate plants experience with temperature loggers. Results: CAP as a predictor decreased the omission error of SDMs, mostly at low and mid elevations, where topography may buffer extreme temperatures, resulting in a more stable microclimate compared to macroclimate. Conclusions: We have shown that plants in an alpine landscape may be less exposed to climate warming than predicted by macroclimate. Topo-climatic GIS layers for SDM projections in mountain environments should integrate such physical mechanisms as CAP