Individual Specialization in a Generalist Apex Predator: The Leopard Seal
ABSTRACT Apex predators are typically considered dietary generalists, which often masks individual variability. However, individual specialization—consistent differences among individuals in resource use or ecological role—is common in apex predators. In some species, only a few specialized individu...
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Wiley
2025-06-01
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| Series: | Ecology and Evolution |
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| Online Access: | https://doi.org/10.1002/ece3.71593 |
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| author | Emily S. Sperou Douglas J. Krause Renato Borras‐Chavez Patrick Charapata Daniel P. Costa Daniel E. Crocker Kerri J. Smith Bradley Thompson Azana Best Jaelyn Anderson Michael E. Goebel Carolina A. Bonin Sarah S. Kienle |
| author_facet | Emily S. Sperou Douglas J. Krause Renato Borras‐Chavez Patrick Charapata Daniel P. Costa Daniel E. Crocker Kerri J. Smith Bradley Thompson Azana Best Jaelyn Anderson Michael E. Goebel Carolina A. Bonin Sarah S. Kienle |
| author_sort | Emily S. Sperou |
| collection | DOAJ |
| description | ABSTRACT Apex predators are typically considered dietary generalists, which often masks individual variability. However, individual specialization—consistent differences among individuals in resource use or ecological role—is common in apex predators. In some species, only a few specialized individuals can significantly impact prey populations. Leopard seals (Hydrurga leptonyx) are apex predators important to the structure and function of the Southern Ocean ecosystem. Though broadly described as generalists, little is known about their trophic ecology at the population or individual level. We analyzed δ13C and δ15N profiles in whiskers (n = 46) from 34 leopard seals in the Western Antarctic Peninsula to assess trophic variation. We also evaluated individual consistency across years using repeat samples from 7 seals over 2–10 years. We compared population and individual isotopic niche space and explored drivers of intraspecific variation in leopard seal trophic ecology. We find that leopard seals have a broad trophic niche (range: 6.96%–15.21‰) and are generalists at the population level. However, most individuals are specialists (59% for δ15N and δ13C), with only a few generalists (13% for δ15N, 6% for δ13C). Individuals also specialize at different trophic levels. Most variation in trophic ecology is driven by individual specialization, but sex and mass also contribute. We also find that some seals specialize over time, consistently foraging at the same trophic level, while others switch within and between years. This suggests some seals may disproportionately impact prey, especially when specialists consistently target specific species. Long‐term specialization by a few leopard seals likely contributed to the decline of the local Antarctic fur seal population. Our findings show the importance of examining individual specialization in leopard seals across their range to understand their impact on other prey populations. This approach should be applied to other apex predator populations, as a few specialists can significantly impact ecosystems. |
| format | Article |
| id | doaj-art-e9aaa54038ca47048c22b14cb039efe3 |
| institution | Kabale University |
| issn | 2045-7758 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Wiley |
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| series | Ecology and Evolution |
| spelling | doaj-art-e9aaa54038ca47048c22b14cb039efe32025-08-20T03:33:26ZengWileyEcology and Evolution2045-77582025-06-01156n/an/a10.1002/ece3.71593Individual Specialization in a Generalist Apex Predator: The Leopard SealEmily S. Sperou0Douglas J. Krause1Renato Borras‐Chavez2Patrick Charapata3Daniel P. Costa4Daniel E. Crocker5Kerri J. Smith6Bradley Thompson7Azana Best8Jaelyn Anderson9Michael E. Goebel10Carolina A. Bonin11Sarah S. Kienle12Department of Biology Baylor University Waco Texas USAAntarctic Marine Living Resources Program, Ecosystem Science Division National Oceanic and Atmospheric Administration (NOAA) Fisheries La Jolla California USADepartment of Biology Baylor University Waco Texas USAEnvironmental Fisheries Science Division, Northwest Fisheries Science Center National Oceanic and Atmospheric Administration (NOAA) Seattle Washington USADepartment of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz California USADepartment of Biology Sonoma State University Rohnert Park California USADepartment of Biology and Marine Biology University of North Carolina Wilmington Wilmington North Carolina USADepartment of Statistical Science Baylor University Waco Texas USADepartment of Biology Baylor University Waco Texas USADepartment of Biology Baylor University Waco Texas USAAntarctic Marine Living Resources Program, Ecosystem Science Division National Oceanic and Atmospheric Administration (NOAA) Fisheries La Jolla California USADepartment of Biological Science Hampton University Hampton Virginia USADepartment of Biology Baylor University Waco Texas USAABSTRACT Apex predators are typically considered dietary generalists, which often masks individual variability. However, individual specialization—consistent differences among individuals in resource use or ecological role—is common in apex predators. In some species, only a few specialized individuals can significantly impact prey populations. Leopard seals (Hydrurga leptonyx) are apex predators important to the structure and function of the Southern Ocean ecosystem. Though broadly described as generalists, little is known about their trophic ecology at the population or individual level. We analyzed δ13C and δ15N profiles in whiskers (n = 46) from 34 leopard seals in the Western Antarctic Peninsula to assess trophic variation. We also evaluated individual consistency across years using repeat samples from 7 seals over 2–10 years. We compared population and individual isotopic niche space and explored drivers of intraspecific variation in leopard seal trophic ecology. We find that leopard seals have a broad trophic niche (range: 6.96%–15.21‰) and are generalists at the population level. However, most individuals are specialists (59% for δ15N and δ13C), with only a few generalists (13% for δ15N, 6% for δ13C). Individuals also specialize at different trophic levels. Most variation in trophic ecology is driven by individual specialization, but sex and mass also contribute. We also find that some seals specialize over time, consistently foraging at the same trophic level, while others switch within and between years. This suggests some seals may disproportionately impact prey, especially when specialists consistently target specific species. Long‐term specialization by a few leopard seals likely contributed to the decline of the local Antarctic fur seal population. Our findings show the importance of examining individual specialization in leopard seals across their range to understand their impact on other prey populations. This approach should be applied to other apex predator populations, as a few specialists can significantly impact ecosystems.https://doi.org/10.1002/ece3.71593foraging strategiesindividual variationintraspecific competitionmarine mammalniche variationspecialist |
| spellingShingle | Emily S. Sperou Douglas J. Krause Renato Borras‐Chavez Patrick Charapata Daniel P. Costa Daniel E. Crocker Kerri J. Smith Bradley Thompson Azana Best Jaelyn Anderson Michael E. Goebel Carolina A. Bonin Sarah S. Kienle Individual Specialization in a Generalist Apex Predator: The Leopard Seal Ecology and Evolution foraging strategies individual variation intraspecific competition marine mammal niche variation specialist |
| title | Individual Specialization in a Generalist Apex Predator: The Leopard Seal |
| title_full | Individual Specialization in a Generalist Apex Predator: The Leopard Seal |
| title_fullStr | Individual Specialization in a Generalist Apex Predator: The Leopard Seal |
| title_full_unstemmed | Individual Specialization in a Generalist Apex Predator: The Leopard Seal |
| title_short | Individual Specialization in a Generalist Apex Predator: The Leopard Seal |
| title_sort | individual specialization in a generalist apex predator the leopard seal |
| topic | foraging strategies individual variation intraspecific competition marine mammal niche variation specialist |
| url | https://doi.org/10.1002/ece3.71593 |
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