Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel)
Abstract Sympatric harbour ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better un...
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Online Access: | http://dx.doi.org/10.1002/ece3.7739 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.7739 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.7739 |
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crwiley:10.1002/ece3.7739 2024-03-17T08:58:17+00:00 Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) Planque, Yann Spitz, Jérôme Authier, Matthieu Guillou, Gaël Vincent, Cécile Caurant, Florence La Rochelle Université Conseil Régional de Picardie 2021 http://dx.doi.org/10.1002/ece3.7739 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.7739 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.7739 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Ecology and Evolution volume 11, issue 15, page 10004-10025 ISSN 2045-7758 2045-7758 Nature and Landscape Conservation Ecology Ecology, Evolution, Behavior and Systematics journal-article 2021 crwiley https://doi.org/10.1002/ece3.7739 2024-02-22T00:44:16Z Abstract Sympatric harbour ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better understanding of the interactions between these species is critical for conservation efforts. This study aimed to identify the trophic niche overlap between harbour and grey seals at the southern limit of their European range, in the Baie de Somme (BDS, Eastern English Channel, France), where numbers of resident harbour seals and visiting grey seals are increasing exponentially. Dietary overlap was identified from scat contents using hierarchical clustering. Isotopic niche overlap was quantified using δ 13 C and δ 15 N isotopic values from whiskers of 18 individuals, by estimating isotopic standard ellipses with a novel hierarchical model developed in a Bayesian framework to consider both intraindividual variability and interindividual variability. Foraging areas of these individuals were identified from telemetry data. The three independent approaches provided converging results, revealing a high trophic niche overlap due to consumption of benthic flatfish. Two diet clusters were dominated by either small or large benthic flatfish; these comprised 85.5% [CI95%: 80.3%–90.2%] of harbour seal scats and 46.8% [35.1%–58.4%] of grey seal scats. The narrower isotopic niche of harbour seals was nested within that of grey seals (58.2% [22.7%–100%] overlap). Grey seals with isotopic values similar to harbour seals foraged in coastal waters close to the BDS alike harbour seals did, suggesting the niche overlap may be due to individual grey seal strategies. Our findings therefore provide the basis for potential competition between both species (foraging on benthic flatfish close to the BDS). We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive ... Article in Journal/Newspaper harbour seal Phoca vitulina Wiley Online Library Ecology and Evolution 11 15 10004 10025 |
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Open Polar |
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Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
topic |
Nature and Landscape Conservation Ecology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Nature and Landscape Conservation Ecology Ecology, Evolution, Behavior and Systematics Planque, Yann Spitz, Jérôme Authier, Matthieu Guillou, Gaël Vincent, Cécile Caurant, Florence Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) |
topic_facet |
Nature and Landscape Conservation Ecology Ecology, Evolution, Behavior and Systematics |
description |
Abstract Sympatric harbour ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better understanding of the interactions between these species is critical for conservation efforts. This study aimed to identify the trophic niche overlap between harbour and grey seals at the southern limit of their European range, in the Baie de Somme (BDS, Eastern English Channel, France), where numbers of resident harbour seals and visiting grey seals are increasing exponentially. Dietary overlap was identified from scat contents using hierarchical clustering. Isotopic niche overlap was quantified using δ 13 C and δ 15 N isotopic values from whiskers of 18 individuals, by estimating isotopic standard ellipses with a novel hierarchical model developed in a Bayesian framework to consider both intraindividual variability and interindividual variability. Foraging areas of these individuals were identified from telemetry data. The three independent approaches provided converging results, revealing a high trophic niche overlap due to consumption of benthic flatfish. Two diet clusters were dominated by either small or large benthic flatfish; these comprised 85.5% [CI95%: 80.3%–90.2%] of harbour seal scats and 46.8% [35.1%–58.4%] of grey seal scats. The narrower isotopic niche of harbour seals was nested within that of grey seals (58.2% [22.7%–100%] overlap). Grey seals with isotopic values similar to harbour seals foraged in coastal waters close to the BDS alike harbour seals did, suggesting the niche overlap may be due to individual grey seal strategies. Our findings therefore provide the basis for potential competition between both species (foraging on benthic flatfish close to the BDS). We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive ... |
author2 |
La Rochelle Université Conseil Régional de Picardie |
format |
Article in Journal/Newspaper |
author |
Planque, Yann Spitz, Jérôme Authier, Matthieu Guillou, Gaël Vincent, Cécile Caurant, Florence |
author_facet |
Planque, Yann Spitz, Jérôme Authier, Matthieu Guillou, Gaël Vincent, Cécile Caurant, Florence |
author_sort |
Planque, Yann |
title |
Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) |
title_short |
Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) |
title_full |
Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) |
title_fullStr |
Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) |
title_full_unstemmed |
Trophic niche overlap between sympatric harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) at the southern limit of their European range (Eastern English Channel) |
title_sort |
trophic niche overlap between sympatric harbour seals ( phoca vitulina ) and grey seals ( halichoerus grypus ) at the southern limit of their european range (eastern english channel) |
publisher |
Wiley |
publishDate |
2021 |
url |
http://dx.doi.org/10.1002/ece3.7739 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.7739 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.7739 |
genre |
harbour seal Phoca vitulina |
genre_facet |
harbour seal Phoca vitulina |
op_source |
Ecology and Evolution volume 11, issue 15, page 10004-10025 ISSN 2045-7758 2045-7758 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/ece3.7739 |
container_title |
Ecology and Evolution |
container_volume |
11 |
container_issue |
15 |
container_start_page |
10004 |
op_container_end_page |
10025 |
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1793767817149939712 |