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Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal

Partitioning resources is a key mechanism for avoiding intraspecific competition and maximizing individual energy gain. However, in sexually dimorphic species it is difficult to discern if partitioning is due to competition or the different resource needs of morphologically distinct individuals. In...

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Autores principales: Hindell, Mark A., McMahon, Clive R., Jonsen, Ian, Harcourt, Robert, Arce, Fernando, Guinet, Christophe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882946/
https://www.ncbi.nlm.nih.gov/pubmed/33613994
http://dx.doi.org/10.1002/ece3.7147
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author Hindell, Mark A.
McMahon, Clive R.
Jonsen, Ian
Harcourt, Robert
Arce, Fernando
Guinet, Christophe
author_facet Hindell, Mark A.
McMahon, Clive R.
Jonsen, Ian
Harcourt, Robert
Arce, Fernando
Guinet, Christophe
author_sort Hindell, Mark A.
collection PubMed
description Partitioning resources is a key mechanism for avoiding intraspecific competition and maximizing individual energy gain. However, in sexually dimorphic species it is difficult to discern if partitioning is due to competition or the different resource needs of morphologically distinct individuals. In the highly dimorphic southern elephant seal, there are intersexual differences in habitat use; at Iles Kerguelen, males predominantly use shelf waters, while females use deeper oceanic waters. There are equally marked intrasexual differences, with some males using the nearby Kerguelen Plateau, and others using the much more distant Antarctic continental shelf (~2,000 km away). We used this combination of inter and intrasexual behavior to test two hypotheses regarding habitat partitioning in highly dimorphic species. (a) that intersexual differences in habitat use will not appear until the seals diverge in body size and (b) that some habitats have higher rates of energy return than others. In particular, that the Antarctic shelf would provide higher energy returns than the Kerguelen Shelf, to offset the greater cost of travel. We quantified the habitat use of 187 southern elephant seals (102 adult females and 85 subadult males). The seals in the two groups were the same size (~2.4 m) removing the confounding effect of body size. We found that the intersexual differences in habitat use existed before the divergence in body size. Also, we found that the amount of energy gained was the same in all of the major habitats. This suggests that the use of shelf habitats by males is innate, and a trade‐off between the need to access the large benthic prey available on shelf waters, against the higher risk of predation there. Intrasexual differences in habitat use are another trade‐off; although there are fewer predators on the Antarctic shelf, it is subject to considerable interannual fluctuations in sea‐ice extent. In contrast, the Kerguelen Plateau presents more consistent foraging opportunities, but contains higher levels of predation. Habitat partitioning in this highly dimorphic species is therefore the result of complex interplay of life history strategies, environmental conditions and predation pressure.
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spelling pubmed-78829462021-02-19 Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal Hindell, Mark A. McMahon, Clive R. Jonsen, Ian Harcourt, Robert Arce, Fernando Guinet, Christophe Ecol Evol Original Research Partitioning resources is a key mechanism for avoiding intraspecific competition and maximizing individual energy gain. However, in sexually dimorphic species it is difficult to discern if partitioning is due to competition or the different resource needs of morphologically distinct individuals. In the highly dimorphic southern elephant seal, there are intersexual differences in habitat use; at Iles Kerguelen, males predominantly use shelf waters, while females use deeper oceanic waters. There are equally marked intrasexual differences, with some males using the nearby Kerguelen Plateau, and others using the much more distant Antarctic continental shelf (~2,000 km away). We used this combination of inter and intrasexual behavior to test two hypotheses regarding habitat partitioning in highly dimorphic species. (a) that intersexual differences in habitat use will not appear until the seals diverge in body size and (b) that some habitats have higher rates of energy return than others. In particular, that the Antarctic shelf would provide higher energy returns than the Kerguelen Shelf, to offset the greater cost of travel. We quantified the habitat use of 187 southern elephant seals (102 adult females and 85 subadult males). The seals in the two groups were the same size (~2.4 m) removing the confounding effect of body size. We found that the intersexual differences in habitat use existed before the divergence in body size. Also, we found that the amount of energy gained was the same in all of the major habitats. This suggests that the use of shelf habitats by males is innate, and a trade‐off between the need to access the large benthic prey available on shelf waters, against the higher risk of predation there. Intrasexual differences in habitat use are another trade‐off; although there are fewer predators on the Antarctic shelf, it is subject to considerable interannual fluctuations in sea‐ice extent. In contrast, the Kerguelen Plateau presents more consistent foraging opportunities, but contains higher levels of predation. Habitat partitioning in this highly dimorphic species is therefore the result of complex interplay of life history strategies, environmental conditions and predation pressure. John Wiley and Sons Inc. 2021-01-29 /pmc/articles/PMC7882946/ /pubmed/33613994 http://dx.doi.org/10.1002/ece3.7147 Text en © 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Research
Hindell, Mark A.
McMahon, Clive R.
Jonsen, Ian
Harcourt, Robert
Arce, Fernando
Guinet, Christophe
Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
title Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
title_full Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
title_fullStr Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
title_full_unstemmed Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
title_short Inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
title_sort inter‐ and intrasex habitat partitioning in the highly dimorphic southern elephant seal
topic Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882946/
https://www.ncbi.nlm.nih.gov/pubmed/33613994
http://dx.doi.org/10.1002/ece3.7147
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