Sébastien Lavergne

We aim at reconstructing the evolutionary history of alpine floras, with a special emphasis on their endemic component and on species clades that have colonized high alpine environments and developed remarkable adaptations such as cushion life-forms. At the macroevolutionary scale, we try to relate the emergence of novel climatic niches, morphological evolution and species diversification. At the microevolutionary scale, we focus on several artico-alpine species typical of high-mountain cliff ecosystems to determine whether they exhibit some potential of local persistence against climatic fluctuations. To do so, we combine population genomics and paleoclimatic data to determine the long-term demographic history of their populations, their degree of local adaptation and their potential for adaptive evolution.

Database of cushion plants of the world

Birds typically exhibit an amazing ecological diversity, with species differing in their climatic requirements, the habitats they use for feeding and breeding and the food resources they consume. We apply phylogenetic comparative analyses to disentangle the evolutionary patterns of ecological niches in different assemblages of bird species, and on different bird clades. We are also interested in understanding the evolutionary origins of long distance migration behaviors by relating them to niche dynamics at a macroevolutionary scale, and in inferring how life-history evolution has triggered or slown down speciation rates.

Invasive species offer unique experimental conditions to unravel the mechanisms allowing species range changes and the assembly of natural communities. Until recently, biological invasions were considered to be mainly driven by ecological processes, but evidence has been accumulating that the naturalization and subsequent spread of a species following a geographic translocation is influenced by short term evolutionary changes but also by the macro-evolutionary history of biotas. We are trying to understand how species' immigration history, stochastic processes and response to new selective conditions drive species invasions along environmental gradients. To do so, we put a special emphasis on the evolutionary processes occuring at range margins and migration fronts and on how changes in individal phenotypes underpins geographic spread. Finally, as species invasions can also be viewed as a legacy of past macroevolutionary history, we are interested in testing whether phylogenetic relatedness of invaders to native communities tend to promote their naturalization, and whether past diversification of native biota can hamper the naturalization of introduced species.