Peak morphological diversity in an ecotone unveiled in the chukar partridge by a novel Estimator in a Dependent Sample (EDS)

Authors

  • Salit Kark,

    Corresponding author
    1. Department of Biological Sciences, Stanford University, Stanford, CA 94305–5020, USA;
    2. Department of Geophysics, Stanford University, Stanford, CA 94305, USA;
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  • Tapan Mukerji,

    1. Department of Evolution, Systematics and Ecology, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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  • Uriel N. Safriel,

    1. Department of Geophysics, Stanford University, Stanford, CA 94305, USA;
    2. Jacob Blaustein Institute for Desert Research, Sede Boqer Campus, Ben-Gurion University of the Negev, 84990, Israel;
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  • Imanuel Noy-Meir,

    1. Department of Agricultural Botany, The Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel,
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  • Rachel Nissani,

    1. Clinical Genetics Unit, Kaplan Hospital, Rehovot 76100, Israel
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  • Ariel Darvasi

    1. Department of Geophysics, Stanford University, Stanford, CA 94305, USA;
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Dr Salit Kark, Department of Evolution, Systematics and Ecology, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. Tel: 972-2-6585075. Fax: 972-2-6584741. E-mail: salit@mail.ls.huji.ac.il

Summary

  • 1Areas of environmental transition (i.e. ecotones) have recently been shown to play an important role in the maintenance of genetic diversity, divergence and in speciation processes. We test the hypothesis that ecotone populations maintain high phenotypic diversity compared to other populations across the distribution range.
  • 2Focusing on the chukar partridge (Alectoris chukar Gray), we study trends in morphological diversity across a steep ecotone within the species native range in Israel and Sinai. Using 35 traits and 23 ratios between traits, we apply a novel weighted average statistic that we term ‘Estimator in a Dependent Sample’ (EDS). This estimator enables us to compare levels of diversity across populations using multiple-correlated traits and is especially useful when sample sizes are small.
  • 3We provide a program for calculating the EDS and a bootstrapping procedure to describe its confidence interval and standard deviation. This estimator can be applied widely in a range of studies using multiple-correlated traits in evolutionary biology, ecology, morphology, behaviour, palaeontology, developmental biology and genetics.
  • 4Our results indicate that within-population diversity peaks in chukar populations located in the Mediterranean-desert ecotone in Israel. However, had we not included the ecotone region in our study, we would have drawn different conclusions regarding patterns of morphological diversity across the range. We suggest that ecotones should be given higher priority in future research and conservation planning, potentially serving as within-species diversity hotspots.

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