Marine Biology

, Volume 152, Issue 4, pp 793–801 | Cite as

Genetic sub-structure and intermediate optimal outcrossing distance in the marine angiosperm Zostera marina

  • Martin R. BillinghamEmail author
  • Tiago Simões
  • Thorsten B. H. Reusch
  • Ester A. Serrão
Research Article


The spatial distribution of genetic variability depends on the spatial patterns of clonal and sexual reproduction, gene flow, genetic drift and natural selection. Species with restricted dispersal may exhibit genetic structuring within populations with immediate neighbours being close relatives, and may show differentiation among populations. Genetic structuring of a species may have important genetic, evolutionary and ecological consequences including distance-dependent mating success. In this study we used microsatellite markers to show that clones of Zostera marina in a population in the Ria Formosa, Portugal, were aggregated and covered distances of up to 3–4 m. Clones within 4 m of each other exhibited significant and positive coancestry values, reflecting the limited seed dispersal of this species. Hand-pollinations between near (0–10.9 m), intermediate (11–32 m) and far (15 km) individuals resulted in similar levels of seed set, although the near pollinations had higher, although not statistically significant, levels of seed abortion during maturation. Seeds from intermediate-distance pollinations had a significantly higher proportion of seeds germinate and shorter germination time than both the near and far seeds. Similarly, the average number of seedlings produced per pollination, used as an overall estimate of fitness, was significantly greater for the intermediate distance when compared to both near and far pollinations. These results suggest that the genetic structuring observed may result in both inbreeding and outbreeding depression, which gives rise to an intermediate optimal outcrossing distance.


Genetic Structure Female Flower Inbreeding Depression Pollen Donor Intermediate Distance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We thank S. Lopes, C. B. Capela and A. L. Quaresma at the Parque Natural de Ria Formosa for boat logistics. Thanks also to A. Hämmerli and C. Perrin for comments on an earlier version of the manuscript. This work was supported by FCT (Portugal) and ESF (European Social Fund) fellowships to MRB, the EU project EVK3-CT-2000-00044–Monitoring and Management of European Seagrass Beds (M&MS) and the FCT (Portugal) project PNAT/1999/BIA/15003/C and complies with the current laws in Portugal.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Martin R. Billingham
    • 1
    • 2
    Email author
  • Tiago Simões
    • 1
  • Thorsten B. H. Reusch
    • 3
    • 4
  • Ester A. Serrão
    • 1
  1. 1.CCMAR, CIMAR- Laboratório Associado, F.C.M.AUniversidade do AlgarveGambelas, FaroPortugal
  2. 2.Institute for Conservation Biology, Department of Biological SciencesUniversity of WollongongWollongongAustralia
  3. 3.Max-Planck-Institut für LimnologiePlönGermany
  4. 4.Institute for Evolution and BiodiversityUniversity of MuensterMuensterGermany

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