| Summary: | Ongoing global changes may lead to shifts in the geographical range of biological species. Adaptive evolution and phenotypic plasticity will determine these shifts. The demography of the species and their dispersal capacities will also determine their ability to colonize newly favourable habitats. When geographical distributions are shifting, one can expect a variation in life history traits across the geographic range. Indeed, survival, reproduction and dispersal capacity will determine the success or failure of population establishment and persistence. These traits are thus theoretically expected to be maximized on colonization fronts because low recruitment rates, mate limitation and inbreeding depression, among other factors, can lead to population decline, local extinction, or colonization failure. On colonization fronts, we therefore expect to observe an increase in dispersal capacities and self-fertilization rate, advanced phenology, and higher fertility compared to populations located in the central part of the range. On retraction fronts, mate limitation can also drive selection for increased self-fertilization, and worsening habitat conditions can lead to higher investment in survival as compared to central populations. Understanding the evolution of life history traits in relation to species range dynamics is therefore essential to better understand the future evolution of biodiversity in the Anthropocene. In this context, spatial variations of life history traits were characterized for four plant species that show expansion or retraction fronts in northern France: Miner’ lettuce (Claytonia perfoliata), Danish scurvygrass (Cochlearia danica), Rock samphire (Crithmum maritimum) and Dune pansy (Viola tricolor subsp. curtisii). Variations of life history traits were surveyed from the core to the edge of their geographic ranges by using phenotypic measurements in the natural environment and in the common garden and by analysing the spatial genetic structure for a subset of two species. The geographical ...
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