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Long-term survival despite low genetic diversity in the critically endangered Madagascar fish-eagle

Authors

  • JEFF A. JOHNSON,

    1. The Peregrine Fund, 5668 West Flying Hawk Lane, Boise, ID 83709, USA
    2. Department of Biological Sciences and Institute of Applied Sciences, University of North Texas, 1155 Union Circle #310559, Denton, TX 76203, USA
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  • RUTH E. TINGAY,

    1. The Peregrine Fund, 5668 West Flying Hawk Lane, Boise, ID 83709, USA
    2. Natural Research Ltd, Burn O’Bennie Road, Banchory AB31 5ZU, Scotland, UK
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  • MELANIE CULVER,

    1. Arizona Cooperative Fish & Wildlife Research Unit, USGS, University of Arizona, Tucson, AZ 85721, USA
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  • FRANK HAILER,

    1. Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, 75236 Uppsala, Sweden
    2. Center for Conservation and Evolutionary Genetics, National Zoological Park & National Museum of Natural History, Smithsonian Institution, PO Box 37012, Washington, DC 20013, USA
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  • MICHÈLE L. CLARKE,

    1. School of Geography, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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  • DAVID P. MINDELL

    1. California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
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J. A. Johnson, Fax: +940 565 4297; E-mail: jajohnson@unt.edu

Abstract

The critically endangered Madagascar fish-eagle (Haliaeetus vociferoides) is considered to be one of the rarest birds of prey globally and at significant risk of extinction. In the most recent census, only 222 adult individuals were recorded with an estimated total breeding population of no more than 100–120 pairs. Here, levels of Madagascar fish-eagle population genetic diversity based on 47 microsatellite loci were compared with its sister species, the African fish-eagle (Haliaeetus vocifer), and 16 of these loci were also characterized in the white-tailed eagle (Haliaeetus albicilla) and the bald eagle (Haliaeetus leucocephalus). Overall, extremely low genetic diversity was observed in the Madagascar fish-eagle compared to other surveyed Haliaeetus species. Determining whether this low diversity is the result of a recent bottleneck or a more historic event has important implications for their conservation. Using a Bayesian coalescent-based method, we show that Madagascar fish-eagles have maintained a small effective population size for hundreds to thousands of years and that its low level of neutral genetic diversity is not the result of a recent bottleneck. Therefore, efforts made to prevent Madagascar fish-eagle extinction should place high priority on maintenance of habitat requirements and reducing direct and indirect human persecution. Given the current rate of deforestation in Madagascar, we further recommend that the population be expanded to occupy a larger geographical distribution. This will help the population persist when exposed to stochastic factors (e.g. climate and disease) that may threaten a species consisting of only 200 adult individuals while inhabiting a rapidly changing landscape.

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