Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation
Sexual segregation (sex differences in spatial organisation and resource use) is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affec...
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ftpubmed:oai:pubmedcentral.nih.gov:3445520 2023-05-15T15:33:37+02:00 Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation Leung, Elaine S. Chilvers, B. Louise Nakagawa, Shinichi Moore, Antoni B. Robertson, Bruce C. 2012-09-18 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445520 http://www.ncbi.nlm.nih.gov/pubmed/23028978 https://doi.org/10.1371/journal.pone.0045389 en eng Public Library of Science http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445520 http://www.ncbi.nlm.nih.gov/pubmed/23028978 http://dx.doi.org/10.1371/journal.pone.0045389 This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. CC-BY Research Article Text 2012 ftpubmed https://doi.org/10.1371/journal.pone.0045389 2013-09-04T13:05:09Z Sexual segregation (sex differences in spatial organisation and resource use) is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ) sea lion (Phocarctos hookeri), a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account sex differences in foraging behaviour, as well as differential ... Text Auckland Island PubMed Central (PMC) New Zealand PLoS ONE 7 9 e45389 |
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Research Article Leung, Elaine S. Chilvers, B. Louise Nakagawa, Shinichi Moore, Antoni B. Robertson, Bruce C. Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation |
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Research Article |
description |
Sexual segregation (sex differences in spatial organisation and resource use) is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ) sea lion (Phocarctos hookeri), a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account sex differences in foraging behaviour, as well as differential ... |
format |
Text |
author |
Leung, Elaine S. Chilvers, B. Louise Nakagawa, Shinichi Moore, Antoni B. Robertson, Bruce C. |
author_facet |
Leung, Elaine S. Chilvers, B. Louise Nakagawa, Shinichi Moore, Antoni B. Robertson, Bruce C. |
author_sort |
Leung, Elaine S. |
title |
Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation |
title_short |
Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation |
title_full |
Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation |
title_fullStr |
Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation |
title_full_unstemmed |
Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation |
title_sort |
sexual segregation in juvenile new zealand sea lion foraging ranges: implications for intraspecific competition, population dynamics and conservation |
publisher |
Public Library of Science |
publishDate |
2012 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445520 http://www.ncbi.nlm.nih.gov/pubmed/23028978 https://doi.org/10.1371/journal.pone.0045389 |
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New Zealand |
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New Zealand |
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Auckland Island |
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Auckland Island |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445520 http://www.ncbi.nlm.nih.gov/pubmed/23028978 http://dx.doi.org/10.1371/journal.pone.0045389 |
op_rights |
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1371/journal.pone.0045389 |
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PLoS ONE |
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7 |
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