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Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa
Includes abstract.
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2014
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| _version_ | 1867613897313222657 |
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| access_status_str | Open Access |
| author | Barquete, Viviane |
| author2 | Ryan, Peter G |
| author_browse | Barquete, Viviane Ryan, Peter G |
| author_facet | Ryan, Peter G Barquete, Viviane |
| author_sort | Barquete, Viviane |
| collection | Thesis |
| description | Includes abstract. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/6229 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:43:26.831Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/6229 Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa Barquete, Viviane Ryan, Peter G Wanless, Ross M Zoology Includes abstract. Includes bibliographical references. Stable isotopes (SI) have been widely applied in ecology to investigate the trophic relationships of animals. Stable isotope analyses were used to augment our understanding of the foraging ecology and movements of three globally threatened seabirds: African Penguins (Spheniscus demersus), Cape Gannets (Morus capensis) and White-chinned Petrels (Procellaria aequinoctiallis). The diets of captive penguins were varied to estimate the 15N turnover rates and discrimination factors of toenails and blood fractions. Plasma δ15N showed a faster turnover rate (7.6 ± 0.7 days) than erythrocytes (14.3 ± 1.6 days). Discrimination factors varied among tissues. No shift in nail δ15N signature was detected after 5 months, suggesting that toenails are insensitive to short to medium-term diet shifts. Among wild penguins and gannets sampled across the Benguela region, tow different responses to the effects of fisheries were observed,due to different feeding strategies, Age, sex year and colony location accounted for isotopic variation. Age-based differences may be linked to limited foraging skills of juvenile birds and their wider dispersion. Female gannets apparently feed on more live natural prey whereas males take more fishery discards, although the sex-based difference was confounded by colony effect. Marked inter-colony variation probably results from regional differences in oceanic conditions between, prey availability and among gannets, variation in dependence on fishery discards. Inter-annual variation in SI signatures might be linked to variation in primary production (African Penguins), or variation in prey availability (Cape Gannets)... 2014-08-13T14:14:13Z 2014-08-13T14:14:13Z 2012 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/6229 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Zoology Barquete, Viviane Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa |
| thesis_degree_str | Doctoral |
| title | Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa |
| title_full | Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa |
| title_fullStr | Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa |
| title_full_unstemmed | Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa |
| title_short | Using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off Southern Africa |
| title_sort | using stable isotopes as a tool to understand the trophic relationships and movement of seabirds off southern africa |
| topic | Zoology |
| url | http://hdl.handle.net/11427/6229 |
| work_keys_str_mv | AT barqueteviviane usingstableisotopesasatooltounderstandthetrophicrelationshipsandmovementofseabirdsoffsouthernafrica |