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Effects of long-distance dispersal for metapopulation survival and genetic structure at ecological time and spatial scales

Authors

  • GIL BOHRER,

    Corresponding author
    1. Department of Civil and Environmental Engineering, Hudson Hall 121, Duke University, Durham 27708, NC, USA,
      Gil Bohrer (fax + 1 919 6605219; e-mail gil.bohrer@duke.edu).
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  • RAN NATHAN,

    1. Department of Civil and Environmental Engineering, Hudson Hall 121, Duke University, Durham 27708, NC, USA,
    2. Department of Evolution, Systematics and Ecology, The Alexander Silberman Institute of Life Sciences, The Hebrew University in Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel, and
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  • SERGEI VOLIS

    1. Department of Civil and Environmental Engineering, Hudson Hall 121, Duke University, Durham 27708, NC, USA,
    2. Department of Life Sciences, Ben-Gurion University of the Negev, POB 653, Beer Sheva 84105, Israel
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Gil Bohrer (fax + 1 919 6605219; e-mail gil.bohrer@duke.edu).

Summary

  • 1Long-distance dispersal (LDD) of seeds by wind plays an important role in population survival and structure, especially in naturally patchy or human-fragmented metapopulations. However, no study has tested its effects using a realistic dispersal kernel in a metapopulation context with explicit spatial structure and local extinctions.
  • 2We incorporated such kernels into a newly proposed simulation model, which combines within-patch (population) demographic processes and a simplified maternally inherited single-locus, two-allele genetic make-up of the populations. As a test case, we modelled a typical conservation scenario of Aleppo pine (Pinus halepensis) populations.
  • 3The effects of LDD were rather diverse and depended on initial population conditions and local extinction rates. LDD increased metapopulation survival at intermediate local-extinction probabilities. LDD helped maintain higher total genetic variability in populations that were initially drifted, but facilitated random genetic loss through drift in initially ‘well mixed’ populations. LDD prevented population differentiation in low extinction rates but increased it at intermediate to high extinction rates.
  • 4Our results suggest that LDD has broader evolutionary implications and would be selected for in populations facing intermediate local-extinction pressures. Our modelling approach provides a strong tool to test the effects of LDD on metapopulation survival and genetic variability and to identify the parameters to which such effects are most sensitive, in ecological and conservational scenarios.

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