C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon).

Autor: Thibault M; Centre d'Écologie et des Sciences de la Conservation (CESCO), Muséum National d'Histoire Naturelle, Station de Biologie Marine, 1 Place de la Croix, 29900, Concarneau, France. martin.thibault@ird.fr.; UMR ENTROPIE (UR-IRD-IFREMER-CNRS-UNC), Labex-CORAIL, 98800, Nouméa, New Caledonia. martin.thibault@ird.fr., Letourneur Y; UMR ENTROPIE (UR-IRD-IFREMER-CNRS-UNC), Labex-CORAIL, 98800, Nouméa, New Caledonia., Cleguer C; Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), James Cook University, Townsville, Australia., Bonneville C; UMR ENTROPIE (UR-IRD-IFREMER-CNRS-UNC), Labex-CORAIL, 98800, Nouméa, New Caledonia., Briand MJ; CRIOBE, USR 3278 EPHE-CNRS-UPVD, LabEx « Corail », PSL Research University, Université de Perpignan, Avenue Paul Alduy, 66860, Perpignan Cedex, France., Derville S; UMR ENTROPIE (UR-IRD-IFREMER-CNRS-UNC), Labex-CORAIL, 98800, Nouméa, New Caledonia.; Opération Cétacés, BP 12827, 98802, Nouméa, New Caledonia., Bustamante P; Littoral Environnement Et Sociétés (LIENSs), UMR 7266, CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, 17000, La Rochelle, France., Garrigue C; UMR ENTROPIE (UR-IRD-IFREMER-CNRS-UNC), Labex-CORAIL, 98800, Nouméa, New Caledonia.; Opération Cétacés, BP 12827, 98802, Nouméa, New Caledonia.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2024 Jan 09; Vol. 14 (1), pp. 896. Date of Electronic Publication: 2024 Jan 09.
DOI: 10.1038/s41598-023-50578-3
Abstrakt: The dugong (Dugong dugon), a large marine mammal herbivore of the Indo-Pacific, is vulnerable to extinction at a global scale due to a combination of human-related threats including habitat degradation. The species forages on seagrass habitats (marine phanerogams) and plays a key role in the functioning and sensitivity of these declining coastal ecosystems. The trophic behaviour and plasticity of dugong populations in response to extrinsic and intrinsic factors are therefore crucial features to both dugong and seagrass conservation. Yet, this knowledge remains limited to few visual observations and analyses of mouth, stomach or faecal contents of stranded individuals. We take advantage of a long-term monitoring of stranded individuals from the endangered New Caledonian population to depict features of dugongs' trophic ecology from Carbon and Nitrogen stable isotopes. A total of 59 dugong skin samples were used to portrait the stable isotope niche of dugongs according to their sex and maturity. In light of previous work conducted in New Caledonia, a subset of these samples was used to model the trophic mix of dugong males and females. Our stable isotope mixing models used C and N isotope values of 10 taxa bbelonging to five divisions of metazoans, plants, and chromists. Our results represent the first estimate of the species dietary niche in the isotopic space. They suggest that the diet of dugong calves overlaps more with that of adult females (δ 13 C: - 6.38 ± 1.13 ‰; δ 15 N: 2.49 ± 1.10 ‰) than males (δ 13 C: - 5.92 ± 1.10 ‰; δ 15 N: 3.69 ± 1.28 ‰). Further, we highlight differences in the expected trophic mix of dugong adult males and females. From these, we formulate a sex-specific foraging behaviour hypothesis in dugongs, whereby lactating females could forage over smaller spatial ranges but more diverse food sources thanmales. The study emphasizes the importance of long-term stranding monitoring programs to study the ecology of marine mammals.. Finally, it depicts an ecological feature that may contribute to the sensitivity of vulnerable dugongs to ongoing changes on tropical coastal ecosystems.
(© 2024. The Author(s).)
Databáze: MEDLINE
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