Contrasting genetic structure, mode of reproduction and clonal characteristics in established and newly colonised populations of Carex salina Wahlenb. (Cyperaceae)

The recent colonisation of Carex salina in Scotland presents an opportunity to compare population genetic structure with long-established Norwegian populations. The closely related long-established Scottish C. recta allowed removal of the potentially confounding effects of latitude. To compare genetic diversity, balance between clonal and sexual reproduction, clonal architecture in new and long-established populations of C. salina and C. recta, respectively. Simple sequence repeat markers were used to quantify genetic parameters within all extant populations of C. recta and C. salina in Scotland and in C. salina sampled across its latitudinal range in Norway. Scottish and Norwegian populations of C. salina, and Scottish C. recta showed similar levels of expected heterozygosity. Almost all populations showed heterozygote excess. Clonality was lowest in Scottish C. salina. The few Scottish C. salina clones were large with very little overlap. By comparison, Norwegian C. salina and Scottish C. recta had smaller, overlapping clones. Scottish saltmarshes have been colonised by C. salina on multiple occasions with insufficient time for extensive clonal growth to occur. It will be instructive to undertake future examination of the genetic structure of these Scottish populations to assess how they change over time.