Geographic variation in the trophic ecology of an avian rocky shore predator, the African black oystercatcher, along the southern African coastline
- Authors: Kohler, Sophie A , Connan, Maëlle , Hill, Jaclyn M , Mablouké, Cécile , Bonnevie, Bo T , Ludynia, Katrin , Kemper, Jessica , Huisamen, Johan , Underhill, Leslie G , Cherel, Yves , McQuaid, Christopher D , Jaquemet, Sébastien
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444576 , vital:74252 , https://doi.org/10.3354/meps09215
- Description: The reflection of baseline isotopic signals along marine food chains up to higher trophic levels has been widely used in the study of oceanic top predators but rarely for intertidal predators. We investigated variation in the δ 13 C and δ 15 N ratios of a sedentary, rocky shore predator, the African black oystercatcher Haematopus moquini, over~ 2000 km of the southern African coastline, which is characterized by strong biogeographic patterns in primary productivity and intertidal communities. Blood and feathers from breeding adults and chicks and muscle tissues from primary prey items (mussels and limpets) were sampled between southern Namibia and the southeast coast of South Africa. 15 N enrichment was observed between the southeast and west coasts in oystercatcher tissues and their prey, mirroring an isotope shift between the oligotrophic Agulhas Current on the east coast and the eutrophic Benguela upwelling system on the west coast.
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- Date Issued: 2011
Some considerations when comparing SABAP 1 with SABAP 2 data
- Authors: Bonnevie, Bo T
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448327 , vital:74722 , https://doi.org/10.2989/00306525.2011.603486
- Description: Generally, one should be cautious when comparing data that have not been collected in the same manner. The data collection methods of the South African Bird Atlas Projects, SABAP 1 (Harrison et al. 1997) and SABAP 2 (in progress at the time of writing), differ both spatially and temporally. On the spatial scale SABAP 1 used predominantly quarter degree cells (15′ by 15′), whereas SABAP 2 uses pentads (5′ by 5′; one quarter-degree cell containing nine pentads). On a temporal scale SABAP 1 used one calendar month, whereas SABAP 2 is using one pentade (five days). Where possible, however, SABAP 1 used pentades post hoc for seasonality modelling (Harrison et al. 1997, pp lviii–lix). Because of, but possibly not limited to, this, caution will need to be exercised when comparing data between the two projects. It is naturally desirable to compare the data between these projects, particularly to seek long-term trends in population densities and in the potential changes in the distribution of species.
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- Date Issued: 2011