Within-population spatial genetic structure, neighbourhood size and clonal subrange in the seagrass Cymodocea nodosa

Filipe Alberto, Licínia Gouveia, Sophie Arnaud-Haond, José L. Pérez-Lloréns, Carlos Duarte, Ester A. Serrão*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

The extent of clonality within populations strongly influences their spatial genetic structure (SGS), yet this is hardly ever thoroughly analysed. We employed spatial autocorrelation analysis to study effects of sexual and clonal reproduction on dispersal of the dioecious seagrass Cymodocea nodosa. Analyses were performed both at genet level (i.e. excluding clonal repeats) and at ramet level. Clonal structure was characterized by the clonal subrange, a spatial measure of the linear limits where clonality still affects SGS. We show that the clonal subrange is equivalent to the distance where the probability of clonal identity approaches zero. This combined approach was applied to two meadows with different levels of disturbance, Cadiz (stable) and Alfacs (disturbed). Genotypic richness, the proportion of the sample representing distinct genotypes, was moderate (0.38 Cadiz, 0.46 Alfacs) mostly due to dominance of a few clones. Expected heterozygosities were comparable to those found in other clonal plants. SGS analyses at the genet level revealed extremely restricted gene dispersal in Cadiz (Sp = 0.052, a statistic reflecting the decrease of pairwise kinship with distance), the strongest SGS found for seagrass species, comparable only to values for selfing herbaceous land plants. At Cadiz the clonal subrange extended across shorter distances (20-25 m) than in Alfacs (30-35 m). Comparisons of sexual and vegetative components of gene dispersal suggest that, as a dispersal vector within meadows, clonal spread is at least as important as sexual reproduction. The restricted dispersal and SGS pattern in both meadows indicates that the species follows a repeated seedling recruitment strategy.

Original languageEnglish (US)
Pages (from-to)2669-2681
Number of pages13
JournalMolecular Ecology
Volume14
Issue number9
DOIs
StatePublished - Aug 1 2005

Keywords

  • Clonal plant
  • Clonal subrange
  • Cymodocea nodosa
  • Microsatellites
  • SGS
  • Seagrass

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics

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