Effects of contemporary shifts of range margins on patterns of genetic structure and mating system in two coastal plant species

Species’ geographical ranges are often restricted due to niche limitation resulting in geographical isolation and reduced population size at range margins. Under the ‘abundant center’ paradigm, static marginal populations are thus expected to show higher genetic differentiation and lower genetic diversity than core populations. Low mate availability may also drive shifts towards higher propensity for selfing in geographically marginal populations. However, these predictions remain to be validated for contemporary range shifts occurring under current environmental change. This study is devoted to bridging this gap and assesses the spatial patterns of genetic structure and mating system across the geographical range of two coastal plant species characterized by contrasting contemporary range dynamics: the receding myrmecochorous Dune pansy (Viola tricolor subsp. curtisii) and the widespread expanding hydrochorous Rock samphire (Crithmum maritimum) Both species exhibited high propensity fo...