title: Genetic variation facilitates seedling establishment but not population growth rate of a perennial invader.
abstract: OBJECTIVE
  Assessing the demographic consequences of genetic variation is fundamental to invasion biology. However, genetic and demographic approaches are rarely combined to explore the effects of genetic variation on invasive populations in natural environments. This study combined population genetics, demographic data and a greenhouse experiment to investigate the consequences of genetic variation for the population fitness of the perennial, invasive herb Lupinus polyphyllus.
  
  
  METHODS
  Genetic and demographic data were collected from 37 L. polyphyllus populations representing different latitudes in Finland, and genetic variation was characterized based on 13 microsatellite loci. Associations between genetic variation and population size, population density, latitude and habitat were investigated. Genetic variation was then explored in relation to four fitness components (establishment, survival, growth, fecundity) measured at the population level, and the long-term population growth rate (λ). For a subset of populations genetic variation was also examined in relation to the temporal variability of λ. A further assessment was made of the role of natural selection in the observed variation of certain fitness components among populations under greenhouse conditions.
  
  
  RESULTS
  It was found that genetic variation correlated positively with population size, particularly at higher latitudes, and differed among habitat types. Average seedling establishment per population increased with genetic variation in the field, but not under greenhouse conditions. Quantitative genetic divergence (Q(ST)) based on seedling establishment in the greenhouse was smaller than allelic genetic divergence (F'(ST)), indicating that unifying selection has a prominent role in this fitness component. Genetic variation was not associated with average survival, growth or fecundity measured at the population level, λ or its variability.
  
  
  CONCLUSIONS
  The study suggests that although genetic variation may facilitate plant invasions by increasing seedling establishment, it may not necessarily affect the long-term population growth rate. Therefore, established invasions may be able to grow equally well regardless of their genetic diversity.
authors.affiliation: Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland, Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania, USA, sxl5716@psu.edu.
authors.forename: Shou-Li
authors.initials: SL
authors.lastname: Li
authors.affiliation: Division of Genetics and Physiology, Department of Biology, University of Turku, 20014 Turku, Finland, Department of Aquaculture, Estonian University of Life Sciences, Tartu, Estonia and.
authors.forename: Anti
authors.initials: A
authors.lastname: Vasemägi
authors.affiliation: Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland, Aronia Coastal Zone Research Team, Åbo Akademi University and Novia University of Applied Sciences, Raseborgsvägen 9, 10600 Ekenäs, Finland.
authors.forename: Satu
authors.initials: S
authors.lastname: Ramula
mesh_terms: D000483:Alleles; D017753:Ecosystem; D014644:Genetic Variation; D058865:Introduced Species; D031297:Lupinus / Q000235:genetics* / Q000254:growth & development*; D011156:Population Density; D011157:Population Dynamics; D036226:Seedlings / Q000235:genetics* / Q000254:growth & development*
keywords: Demography; Fabaceae.; Lupinus polyphyllus; fitness; genetic diversity; invasion ecology; life history traits; population dynamics; population growth rate; vital rates