Genetic diversity of pioneer populations: the case of Nassauvia argentea (Asteraceae: Mutisieae) on Volcán Lonquimay, Chile

Abstract

Colonising populations do not always exhibit founder effects. Common explanations are high levels of immigration and/or reproduction, but few empirical tests have been done. We measured genetic diversity of Nassauvia argentea in terms of variation and divergence of plant populations that have colonised Volca´n Lonquimay, Chile, following its latest eruption in 1988. Fifteen individuals from each of ten populations were analysed using amplified fragment length polymorphism (AFLP) markers. Genetic variation and divergence were lower in colonising populations than established ones, but not significantly so (ANOVA and Kruskal-Wallis tests, p\0.05). No consistent or significant trends were obtained from regressions with demographic variables. Bayesian analysis of population structure reveals close relatedness among populations of all ages on the volcano. We concluded that no conspicuous founder effect has occurred in the genetic diversity of populations colonising a newly derived volcanic environment. An important implication of this is the role of proximity to source regions and species vigour in moulding genetic diversity of colonisers from different species.