Using stable isotopes to trace the movements of ducks in southern Africa
Includes bibliographical references. Despite the importance of movement ecology studies, the field faces a prevailing challenge of methodological limitations in tracking individual organisms. This research investigated the utility of the stable isotope technique to trace movements of ducks in southe...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Master Thesis |
| Language: | English |
| Published: |
University of Cape Town
2010
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/11427/9801 https://open.uct.ac.za/bitstream/11427/9801/1/thesis_sci_2010_mutumi_g_l.pdf |
| Summary: | Includes bibliographical references. Despite the importance of movement ecology studies, the field faces a prevailing challenge of methodological limitations in tracking individual organisms. This research investigated the utility of the stable isotope technique to trace movements of ducks in southern Africa. I sampled and analysed feathers of ten duck species for stable isotope proportions of Carbon (δ13C), Nitrogen (δ15N) and Hydrogen (δD), from five wetlands (Strandfontein and Barberspan in South Africa, the Manyame catchment in Zimbabwe, Lake Chuali in Mozambique, and Lake Ngami in Botswana) as test cases.Sampling was carried out at different seasons to account for seasonal isotope signature variations. Isotope signatures of feathers grown at different moulting locations were compared to test whether southern Africa shows stable isotope spatial patterns (distinct isotopic regions). Feathers grown at different life-phases were compared to test whether different sites had been used and if more mobile species showed more and stronger isotope distinctions. Finally, growing flight feathers grown at moulting locations were compared across species to query how much information on diet and foraging behaviour can be inferred from southern African duck feather stable isotopes.Feather isotope signatures were distinct by site in at least one of the tested isotopes, for the majority of ducks tested. Strandfontein had more and stronger distinctions of isotope signatures between feathers grown at different life phases. This site is the closest to the sea and most likely to have marine-influenced isotope signatures especially in δ15N, it falls within the Mediterranean climatic conditions experiencing winter rainfall unlike all the other sites. Vegetation compositions (C3 and C4 plant distributions) therefore vary across sites influencing δ13C patterns. More mobile species (only Egyptian Goose Alopochen aegyptiacus from Strandfontein, and Cape Shoveler Anas smithii from Barberspan; determined by mobility scores from other ... |
|---|