How do reproductive skew and founder group size affect genetic diversity in reintroduced populations?

Authors

  • K. A. MILLER,

    1. Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
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  • N. J. NELSON,

    1. Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
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  • H. G. SMITH,

    1. 10 Todman Rd, Brooklyn, Wellington, New Zealand
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  • J. A. MOORE

    1. Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
    2. University of Alaska Southeast, Biology Department, 11120 Glacier Highway, Juneau, AK 99801, USA
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  • The authors’ research group in the Allan Wilson Centre for Molecular Ecology and Evolution at Victoria University of Wellington has broad interests in conservation and evolutionary genetics, physiological and behavioural ecology, and management of New Zealand vertebrates, particularly reptiles. This study was part of Kim Miller’s doctoral research that focused on genetic diversity in reintroduced populations.

Kim Miller, Fax: +64 4 463 5331; E-mail: kimberly.miller@vuw.ac.nz

Abstract

Reduced genetic diversity can result in short-term decreases in fitness and reduced adaptive potential, which may lead to an increased extinction risk. Therefore, maintaining genetic variation is important for the short- and long-term success of reintroduced populations. Here, we evaluate how founder group size and variance in male reproductive success influence the long-term maintenance of genetic diversity after reintroduction. We used microsatellite data to quantify the loss of heterozygosity and allelic diversity in the founder groups from three reintroductions of tuatara (Sphenodon), the sole living representatives of the reptilian order Rhynchocephalia. We then estimated the maintenance of genetic diversity over 400 years (∼10 generations) using population viability analyses. Reproduction of tuatara is highly skewed, with as few as 30% of males mating across years. Predicted losses of heterozygosity over 10 generations were low (1–14%), and populations founded with more animals retained a greater proportion of the heterozygosity and allelic diversity of their source populations and founder groups. Greater male reproductive skew led to greater predicted losses of genetic diversity over 10 generations, but only accelerated the loss of genetic diversity at small population size (<250 animals). A reduction in reproductive skew at low density may facilitate the maintenance of genetic diversity in small reintroduced populations. If reproductive skew is high and density-independent, larger founder groups could be released to achieve genetic goals for management.

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