Extremely Low mtDNA Diversity and High Genetic Differentiation Reveal the Precarious Genetic Status of Dugongs in New Caledonia, South Pacific

Garrigue, Claire, Bonnerville, Claire Daisy, Cleguer, Christophe, and Oremus, Marc (2022) Extremely Low mtDNA Diversity and High Genetic Differentiation Reveal the Precarious Genetic Status of Dugongs in New Caledonia, South Pacific. Journal of Heredity, 113 (5). pp. 516-524.

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Abstract

New Caledonia is home to one of the largest remaining populations of dugongs (Dugong dugon) and is located at the southeastern limit of the species range. Local knowledge suggests that current levels of removal due to anthropogenic pressures are unsustainable, whereas trends suggest an ongoing decline in the population. Considering this unfavorable conservation context, this study aimed to assess the New Caledonian dugong population’s resilience by determining its level of genetic diversity and degree of isolation relative to other populations. Mitochondrial DNA (mtDNA) control region sequences (n = 55) collected from live and dead dugongs in New Caledonia were compared with a global data set of previously published sequences (n = 631) representing dugong populations throughout the species range. The New Caledonian dugong population displayed the lowest level of mtDNA diversity documented worldwide (3 haplotypes with 1-bp difference), suggesting a recent origin of the current population through limited colonization events. Population structure analyses indicate a strong genetic differentiation with all the putative populations represented in the global data set, including large neighboring Australian populations. These results show that the dugong population in New Caledonia is particularly isolated, fragile, and vulnerable to anthropogenic threats and diseases with low potential for resilience through incoming gene flow. Our findings call for an instant conservation response and consideration for IUCN population assessment to support the long-term survival of the New Caledonian dugong population.

Item ID: 75838
Item Type: Article (Research - C1)
ISSN: 1465-7333
Keywords: conservation, dugong, genetic diversity, mtDNA, New Caledonia, Sirenian
Copyright Information: © The Author(s) 2022. Published by Oxford University Press on behalf of The American Genetic Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
Date Deposited: 26 Aug 2022 01:37
FoR Codes: 31 BIOLOGICAL SCIENCES > 3105 Genetics > 310510 Molecular evolution @ 60%
41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410401 Conservation and biodiversity @ 40%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180203 Coastal or estuarine biodiversity @ 40%
18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180504 Marine biodiversity @ 60%
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