Genetic diversity and structure of the declining herb Primula farinosa across different spatial scales
(English)Manuscript (preprint) (Other academic)
Habitat fragmentation and reduced population sizes are important threats to biodiversity. These changes increase the influence of genetic drift and are therefore expected to lead to reduced genetic diversity and increased population differentiation. We analysed patterns of genetic variation in the declining herb Primula farinosa in Sweden. On the mainland, P. farinosa has scattered, isolated occurrences due to habitat fragmentation, whereas on the island of Öland, southeast Sweden, the species remains common. On Öland, populations were sampled on both shallow soils, where fluctuations in population size are substantial, and on deep soils, where populations are more stable. Genetic diversity was investigated at 12 putatively neutral microsatellite loci and at a floral display locus influencing plant fitness. Genetic diversity was found to be lower and more strongly structured on the mainland than on Öland, which is consistent with lower gene flow and increased influence of genetic drift in mainland than in Öland populations. On Öland, genetic diversity was not related to soil depth, suggesting that differences in the magnitude of fluctuations in population size are less important for the structuring of genetic variation in P. farinosa. Moreover, population differentiation was stronger at the floral display locus compared to microsatellite loci, consistent with divergent selection acting on floral display on Öland. Taken together, our findings indicate that to maintain genetic diversity in P. farinosa, management should promote gene flow among populations and variation in the direction of selection on floral display.
Conservation, Population connectivity, Divergent selection, Population size fluctuation, Environmental heterogeneity, Perennial herb
IdentifiersURN: urn:nbn:se:uu:diva-215505OAI: oai:DiVA.org:uu-215505DiVA: diva2:687445