Geographical origins, migration patterns and refugia of Sibbaldia procumbens, an arctic–alpine plant with a fragmented range

• Published in: Journal of Biogeography
• Main Authors: Allen, Geraldine A., Marr, Kendrick L., McCormick, Laurie J., Hebda, Richard J.
• Other Authors: Royal British Columbia Museum, John and Joan Walton Innovation Fund, October Hill Foundation, Natural Sciences and Engineering Research Council of Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: Ice Sheet; North Atlantic; Sibbaldia procumbens
• Online Access: http://dx.doi.org/10.1111/jbi.12543; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjbi.12543; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jbi.12543

Abstract Aim Many plants, especially at high latitudes, have both widespread and highly discontinuous geographical distributions. To increase understanding of how such patterns originate, we examine genetic patterns in the arctic–alpine plant Sibbaldia procumbens . We evaluate the contributions of refugia and the role of long‐distance dispersal in shaping the current range of this species. Location Northern Hemisphere, especially North America. Methods We sampled Sibbaldia from 176 localities, including 168 for S. pro‐cumbens . We analysed sequence variation in three plastid DNA non‐coding regions (the atp I– atp H and trn L– trn F intergenic spacers and the trn L intron), performed Bayesian phylogenetic analyses and statistical parsimony analyses on the combined sequences, and analysed the geographical patterns of haplotype distribution and genetic diversity using data from all populations. Results Sibbaldia procumbens probably originated in the mountains of South and East Asia. We identified highly distinct clades in Europe and North America, which overlapped on oceanic islands of the North Atlantic indicating long‐distance dispersal capability. The North American clade included two lineages, one in California and the other widely distributed across the continent and North Atlantic. Haplotype diversity in the latter lineage was markedly higher to the south, suggesting mid–late Pleistocene southward displacement of North American populations with subsequent migration northwards into previously glaciated regions. In Europe, disjunct geographical regions generally harboured distinct haplotypes. Main conclusions Multiple Pleistocene refugia for S. procumbens occurred in both North America and Europe. North American refugia existed in California and in the southern Rocky Mountains, but in contrast with most widespread arctic–alpine species we found no evidence for a Beringian refugium. Cryptic refugia may have existed within the Cordilleran Ice Sheet. Episodes of range expansion and contraction and long‐distance ...