Toward reconstructing the historical assembly of alpine vegetation in the European Alps: a geogenomic approach – GeoGen

Biodiversity is unevenly distributed across the globe, with many terrestrial hotspots concentrated in mountainous regions. A key feature of alpine regions is their tremendous vegetation diversity occurring along steep and complex environmental gradients, with some vegetation elements such as alpine meadows being among the most diverse herbaceous ecosystems on Earth. However, it remains unknown : (i) when the plant lineages constituting alpine vegetation patterns evolved in relation to long-term changes of mountain physiography, (ii) how species forming different alpine vegetation units were affected by Pleistocene glaciations, and (iii) how alpine vegetation reassembled into nowadays patterns during the course of the Holocene, as a response to climate warming, erosion processes and rising agro-pastoral activities. Here we propose to tackle these questions in order to reconstruct the historical assembly of vegetation within the plant biodiversity hotspot of the European Alps in relation to the legacy of processes which acted at different temporal resolution from thousand- to million-year timescales. To do so, we will explicitly integrate geoscience data depicting past mountain physiography, erosion rates, glacier geomorphology and climate into the analysis of (i) available phylogenetic data covering 90% of the flora of the Alps and related lineages, (ii) compiled intraspecific phylogeographies of over 50 species dominant to different alpine habitats and, (iii) metabarcoding of ancient DNA extracted of sediment cores of 25 lakes across the Alps, using a species-resolved barcoding reference for the whole artic-alpine flora.