E. YASHIRO¹, E. PINTO², A. BURI³, H. NICULITA-HIRZEL⁴, A. ANTOINE GUISAN^2,3, J. R. VAN DER MEER<sup>1

1</sup>University of Lausanne, Department of Fundamental Microbiology, 1015 Lausanne, ²University of Lausanne, Department of Ecology and Evolution, 1015 Lausanne, ³University of Lausanne, Institute of Earth Surface Dynamics, 1015 Lausanne, ⁴Institut Universitaire Romand du Santé au Travail, 1066 Epalinges-Lausanne

The possible effects of climate change on biodiversity is of major concern for scientists, policy-makers, and laypeople. We are studying potential microbial biodiversity changes and co-occurrence patterns with plants and insects within a 700 km2 area of the Western Swiss Alps. Alpine top-soils were sampled across an elevation gradient of 500-3000 m at a hundred sites, and bacterial communities were characterized by sequencing of amplified 16S rRNA gene fragments. Extensive correlations were determined between a wide set of physico-chemical and soil parameters, and bacterial communities, in order to understand the major abiotic drivers shaping community structure. Correlations were further drawn between the occurrence of plant species and bacterial communities at the same sites, in order to understand possible interplays between bacteria, plants, and the environment. Our study helps to understand alpine biodiversity across wide elevational and spatial gradients, and can be used to support diversity models predicting future trends.