title: The rare peat moss Sphagnum wulfianum (Sphagnaceae) did not survive the last glacial period in northern European refugia.
abstract: OBJECTIVE
  Organisms may survive unfavorable conditions either by moving to more favorable areas by means of dispersal or by adapting to stressful environments. Pleistocene glacial periods represent extremely unfavorable conditions for the majority of life forms, especially sessile organisms. Many studies have revealed placements of refugial areas and postglacial colonization patterns of seed plants, but little is still known about areas of long-term survival and historical migration routes of bryophytes. Given overall differences in stress tolerance between seed plants and bryophytes, it is of interest to know whether bryophytes have survived periods of extreme climatic conditions better then seed plants in northern areas.
  
  
  METHODS
  The haploid and rarely spore-producing peat moss Sphagnum wulfianum is mostly found in areas that were covered by ice during the last glacial maximum. Twelve microsatellite markers were amplified from 43 populations (367 shoots) of this species, and data were analyzed using population genetic diversity statistics, Bayesian clustering methods, and coalescence-based inference tools to estimate historical and demographic parameters.
  
  
  RESULTS
  Genetic diversity within populations was low, but populations were highly differentiated, with two main genetic clusters being recognized.
  
  
  CONCLUSIONS
  The two main genetic groups have diverged quite recently in the Holocene, and the pattern of genetic variability and structuring gives no support for survival in Scandinavian refugia during the last glacial period in this species. The dispersal ability of this plant thus seems surprisingly high despite its infrequent spore production.
authors.affiliation: Systematics and Evolution Group, Section of Natural History, Museum of Natural History and Archaeology, Norwegian University of Science and Technology, Trondheim, Norway. magni.kyrkjeeide@ntnu.no
authors.forename: Magni Olsen
authors.initials: MO
authors.lastname: Kyrkjeeide
authors.forename: Kristian
authors.initials: K
authors.lastname: Hassel
authors.forename: Kjell I
authors.initials: KI
authors.lastname: Flatberg
authors.forename: Hans K
authors.initials: HK
authors.lastname: Stenøien
mesh_terms: D000483:Alleles; D017753:Ecosystem; D005060:Europe; D056426:Genetic Loci / Q000235:genetics; D005843:Geography; D006239:Haplotypes / Q000235:genetics; D006579:Heterozygote; D046448:Ice Cover; D018895:Microsatellite Repeats / Q000235:genetics; D010802:Phylogeny; D011110:Polymorphism, Genetic; D044003:Sphagnopsida / Q000235:genetics*; D013997:Time Factors