Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models.
The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ(15)N diet-tissue discrimination factors (∆(15)N). As ∆(15)N values have been experimentally shown to vary amongst consumers, tissues and diet...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3798323?pdf=render |
| _version_ | 1819048318955683840 |
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| author | Jill A Olin Nigel E Hussey Alice Grgicak-Mannion Mark W Fritts Sabine P Wintner Aaron T Fisk |
| author_facet | Jill A Olin Nigel E Hussey Alice Grgicak-Mannion Mark W Fritts Sabine P Wintner Aaron T Fisk |
| author_sort | Jill A Olin |
| collection | DOAJ |
| description | The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ(15)N diet-tissue discrimination factors (∆(15)N). As ∆(15)N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate species-specific ∆(15)N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆(15)N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆(15)N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species that feed on prey from different trophic levels (i.e., different mean δ(15)N dietary values). Overall, the most suitable species-specific ∆(15)N values decreased with increasing dietary-δ(15)N values based on stable isotope Bayesian ellipse overlap estimates of shark and the principal prey functional groups contributing to the diet determined from stomach content analyses. Thus, a single ∆(15)N value was not supported for this speciose group of marine predatory fishes. For example, the ∆(15)N value of 3.7‰ provided the highest percent overlap between prey and predator isotope ellipses for the bonnethead shark (mean diet δ(15)N = 9‰) whereas a ∆(15)N value < 2.3‰ provided the highest percent overlap between prey and predator isotope ellipses for the white shark (mean diet δ(15)N = 15‰). These data corroborate the previously reported inverse ∆(15)N-dietary δ(15)N relationship when both isotope ellipses of principal prey functional groups and the broader identified diet of each species were considered supporting the adoption of different ∆(15)N values that reflect the predators' δ(15)N-dietary value. These findings are critical for refining the application of stable isotope modeling approaches as inferences regarding a species' ecological role in their community will be influenced with consequences for conservation and management actions. |
| first_indexed | 2024-12-21T11:14:22Z |
| format | Article |
| id | doaj.art-33938c4f52e94755829e868810454fef |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-21T11:14:22Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-33938c4f52e94755829e868810454fef2022-12-21T19:05:57ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01810e7756710.1371/journal.pone.0077567Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models.Jill A OlinNigel E HusseyAlice Grgicak-MannionMark W FrittsSabine P WintnerAaron T FiskThe application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ(15)N diet-tissue discrimination factors (∆(15)N). As ∆(15)N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate species-specific ∆(15)N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆(15)N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆(15)N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species that feed on prey from different trophic levels (i.e., different mean δ(15)N dietary values). Overall, the most suitable species-specific ∆(15)N values decreased with increasing dietary-δ(15)N values based on stable isotope Bayesian ellipse overlap estimates of shark and the principal prey functional groups contributing to the diet determined from stomach content analyses. Thus, a single ∆(15)N value was not supported for this speciose group of marine predatory fishes. For example, the ∆(15)N value of 3.7‰ provided the highest percent overlap between prey and predator isotope ellipses for the bonnethead shark (mean diet δ(15)N = 9‰) whereas a ∆(15)N value < 2.3‰ provided the highest percent overlap between prey and predator isotope ellipses for the white shark (mean diet δ(15)N = 15‰). These data corroborate the previously reported inverse ∆(15)N-dietary δ(15)N relationship when both isotope ellipses of principal prey functional groups and the broader identified diet of each species were considered supporting the adoption of different ∆(15)N values that reflect the predators' δ(15)N-dietary value. These findings are critical for refining the application of stable isotope modeling approaches as inferences regarding a species' ecological role in their community will be influenced with consequences for conservation and management actions.http://europepmc.org/articles/PMC3798323?pdf=render |
| spellingShingle | Jill A Olin Nigel E Hussey Alice Grgicak-Mannion Mark W Fritts Sabine P Wintner Aaron T Fisk Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models. PLoS ONE |
| title | Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models. |
| title_full | Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models. |
| title_fullStr | Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models. |
| title_full_unstemmed | Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models. |
| title_short | Variable δ(15)N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models. |
| title_sort | variable δ 15 n diet tissue discrimination factors among sharks implications for trophic position diet and food web models |
| url | http://europepmc.org/articles/PMC3798323?pdf=render |
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