Long‐distance dispersal during the middle–late Pleistocene explains the bipolar disjunction of Carex maritima (Cyperaceae)

• Published in: Journal of Biogeography
• Main Authors: Villaverde, Tamara, Escudero, Marcial, Luceño, Modesto, Martín‐Bravo, Santiago
• Other Authors: Spanish Ministry of Science and Technology, Regional Ministry of Economy, Innovation, Science and Employment
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: Ecology; Ecology, Evolution, Behavior and Systematics; Arctic
• Online Access: http://dx.doi.org/10.1111/jbi.12559; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjbi.12559; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jbi.12559

Abstract Aim We set out to explain the bipolar distribution of Carex maritima , clarifying the direction and timing of dispersal. We also tested mountain‐hopping and direct long‐distance dispersal hypotheses, as well as the relationship of C. maritima with biotic and abiotic factors that could explain the bipolar distribution. Location Arctic/boreal latitudes of both hemispheres. Methods Molecular and bioclimatic data were obtained for C. maritima and related species from section Foetidae . We sequenced two ( rps 16 and 5′ trn K intron) plastid DNA regions (cp DNA ) and the external and internal transcribed spacers ( ETS and ITS ) of the nuclear ribosomal gene region (nr DNA ) and inferred phylogenetic relationships, divergence time estimates and biogeographical patterns using maximum likelihood, statistical parsimony, Bayesian inference and ecological niche modelling. Results Carex maritima populations from the Southern Hemisphere were genetically and ecologically differentiated from their northern counterparts and formed a monophyletic group nested within a paraphyletic C. maritima . Divergence time analysis estimated a middle–late Pleistocene divergence of the southern lineage (0.23 Ma; 95% highest posterior density: 0.03–0.51 Ma). Southern Hemisphere populations are more stenotopic than the Northern Hemisphere ones, which tolerate harsher conditions. Main conclusions Our results point to a middle–late Pleistocene migration of C. maritima by long‐distance dispersal, either directly or via mountain‐hopping, from the Northern Hemisphere to the Southern Hemisphere.