title: Environmental and genetic correlates of allocation to sexual reproduction in the circumpolar plant Bistorta vivipara.
abstract: •
  
  
  OBJECTIVE
  Sexual reproduction often requires more energy and time than clonal reproduction. In marginal arctic conditions, species that can reproduce both sexually and clonally dominate. Plants with this capacity may thrive because they can alter reproduction depending on environmental conditions. Bistorta vivipara is a circumpolar herb that predominately reproduces clonally, but certain environmental conditions promote higher investment in flowers (and possible sexual reproduction). Despite largely reproducing clonally, the herb has high levels of genetic variation, and the processes underlying this paradoxical pattern of variation remain unclear. Here we identified environmental factors associated with sexual investment and examined whether sexual reproduction is associated with higher levels of genetic variation.•
  
  
  METHODS
  We sampled 20 populations of B. vivipara across the high Arctic archipelago of Svalbard. In each population, we measured reproductive traits, environmental variables, and collected samples for genetic analyses. These samples permitted hypotheses to be tested regarding sexual investment and ecological and genetic correlates.•
  
  
  RESULTS
  Increased soil nitrogen and organic matter content and decreased elevation were positively associated with investment in flowers. Increased investment in flowers significantly correlated with more genotypes per population. Linkage disequilibrium was consistent with predominant clonality, but several populations showed higher genetic variation and lower differentiation than expected. There was no geographical genetic structure.•
  
  
  CONCLUSIONS
  In B. vivipara, sexual investment is positively associated with habitat quality. Bistorta vivipara predominantly reproduces clonally, but occasional outcrossing, efficient clonal reproduction, and dispersal by bulbils can explain the considerable genetic variation and weak genetic structure in B. vivipara.
authors.affiliation: School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Bills
authors.affiliation: School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA.
authors.forename: Eric H
authors.initials: EH
authors.lastname: Roalson
authors.affiliation: School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA.
authors.forename: Jeremiah W
authors.initials: JW
authors.lastname: Busch
authors.affiliation: The University Centre in Svalbard, P.O. Box 156, 9171 Longyearbyen, Norway.
authors.forename: Pernille B
authors.initials: PB
authors.lastname: Eidesen
mesh_terms: D001110:Arctic Regions; D004777:Environment; D035264:Flowers / Q000235:genetics* / Q000502:physiology; D040342:Genetic Structures; D014644:Genetic Variation; D005838:Genotype; D010641:Phenotype; D019664:Polygonaceae / Q000235:genetics* / Q000502:physiology; D012098:Reproduction; D012987:Soil / Q000737:chemistry
chemical_list: D012987:Soil
keywords: Bistorta vivipara; Polygonaceae; arctic; clonal reproduction; genetic variation; mixed mating; sexual reproduction