Direct long‐distance dispersal best explains the bipolar distribution of Carex arctogena (Carex sect. Capituligerae, Cyperaceae). (22nd April 2015)

• Record Type: Journal Article
• Authors: Villaverde, Tamara; Escudero, Marcial; Martín‐Bravo, Santiago; Bruederle, Leo P.; Luceño, Modesto; Starr, Julian R.
• Is Part Of: Journal of biogeography. Volume 42:Number 8(2015:Aug.)
• Page Start: 1514
• Page End: 1525
• Publication Date: 2015-04-22
• Subjects: Biogeography -- Periodicals; 578.09
• DOI: 10.1111/jbi.12521
• Languages: English
• ISSNs: 0305-0270

Abstract

<abstract abstract-type="main" id="jbi12521-abs-0001"> <title>Abstract</title> <sec id="jbi12521-sec-0001" sec-type="section"> <title>Aim</title> <p>The bipolar disjunction, a biogeographical pattern defined by taxa with a distribution at very high latitudes in both hemispheres (> 55° N; > 52° S), is only known to occur in about 30 vascular plant species. Our aim was to use the bipolar species <italic>Carex arctogena</italic> to test the four classic hypotheses proposed to explain this exceptional disjunction: convergent evolution, vicariance, mountain‐hopping and direct long‐distance dispersal.</p> </sec> <sec id="jbi12521-sec-0002" sec-type="section"> <title>Location</title> <p>Arctic/boreal and temperate latitudes of both hemispheres.</p> </sec> <sec id="jbi12521-sec-0003" sec-type="section"> <title>Methods</title> <p>A combination of molecular and bioclimatic data was used to test phylogeographical hypotheses in <italic>C. arctogena</italic>. Three chloroplast markers (<italic>atp</italic>F<italic>–atp</italic>H<italic>, matK</italic> and <italic>rps16</italic>) and the nuclear ITS region were sequenced for all species in <italic>Carex</italic> sections <italic>Capituligerae</italic> and <italic>Longespicatae</italic>;<italic> Carex rupestris</italic>, <italic> C. obtusata</italic> and <italic>Uncinia triquetra</italic> were used as outrgroups. Phylogenetic relationships, divergence‐time estimates and biogeographical patterns were inferred using maximum likelihood, statistical parsimony and Bayesian inference.</p> </sec> <sec id="jbi12521-sec-0004" sec-type="section"> <title>Results</title> <p> <italic>Carex</italic> sections <italic>Capituligerae</italic> and <italic>Longespicatae</italic> formed a monophyletic group that diverged during the late Miocene. Two main lineages of <italic>C. arctogena</italic> were inferred. Southern Hemisphere populations of <italic>C. arctogena</italic> shared the same haplotype as a widespread circumboreal lineage. Bioclimatic data show that Southern and Northern Hemisphere populations currently differ in their ecological regimes.</p> </sec> <sec id="jbi12521-sec-0005" sec-type="section"> <title>Main conclusions</title> <p>Two of the four hypotheses accounting for bipolar disjunctions may be rejected. Our results suggest that direct long‐distance dispersal, probably southwards and mediated by birds, best explains the bipolar distribution of <italic>C. arctogena</italic>.</p> </sec> </abstract>