Genetic diversity and distinctiveness in Scottish alpine plants

Abstract

Background: Many alpine plants are rare in Scotland. Their persistence depends on their ability to withstand habitat fragmentation and loss due to changes in land use, increased grazing pressure, and climate change. Aims: We use a phylogeographic approach to address the origin and genetic diversity of Scottish populations, which is relevant for their future management and protection. Methods: We review phylogeographic studies that include Scottish populations of common and rare alpine plants, and present unpublished data for eleven more species. We use results from amplified fragment length polymorphism (AFLP) studies to address the genetic distinctiveness of the Scottish populations and their levels of genetic diversity. Results: A positive correlation was found between relative rarity of each species in Scotland and the level of genetic diversity in Scottish populations compared with the species' total. Scottish populations of all species analysed except Saxifraga cernua belong to larger European/Eurasian genetic groups, and show little genetic distinctiveness. However, in S. cernua and one population of S. stellaris, we found a unique genetic group restricted to Scotland. Conclusions: The ancestors of Scottish populations probably shared refugia with other northern European/Eurasian populations during the last glacial period. The finding of unique genetic groups in two species may call for increased conservation effort targeting these particular species. However, we cannot exclude the possibility of such components also occurring in the other species. To prevent a reduction in overall genetic diversity, which again may reduce adaptive potential, it is important to maintain present distributions.