Using a multi-isotope approach to understand waterfowl movement in southern Africa

Mutumi, Gregory, Cumming, Graeme S., Sullivan, S. Mazeika P., Caron, Alexandre, and Caceres, Carlos (2019) Using a multi-isotope approach to understand waterfowl movement in southern Africa. Condor: an international journal of avian biology, 121 (4).

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Abstract

Many far-ranging species depend heavily on relatively small or temporary resources within a heterogeneous landscape. For waterfowl, most species rely on deep, permanent waterbodies as refugia from predators during annual flightless molt periods when synchronous loss and regrowth of the flight feathers occurs. The movements of ducks to and from molt sites are, however, poorly documented for most Afrotropical species and the dependencies of Afrotropical ducks on key sites are unclear, yet this information is integral to conservation and management efforts. We asked whether stable isotopes of wing feathers could be used to determine the molting origins of Afrotropical ducks in southern Africa. We analyzed isotope ratios of carbon, nitrogen, oxygen, and hydrogen in feathers from 4 different species across 5 different sites (wetlands, ponds, lakes) in South Africa, Zimbabwe, Mozambique, and Botswana. We observed differences among sites for all isotopes (P < 0.05), especially delta C-13 and delta N-15. Based on these differences, we conducted linear discriminant function analysis (LDA) to assess the utility of these isotopes to assign birds to molt locations. We obtained a global classification accuracy = 0.59, although accuracies differed among sites. Our results demonstrate the potential of a multi-isotope approach to discriminate among specific molt locations and to provide an initial estimate of molt site. Rigorous documentation of molt site from wing feathers is plausible, but will require large sample sizes, extensive spatial coverage, and careful calibration.

Item ID: 62486
Item Type: Article (Research - C1)
ISSN: 1938-5129
Keywords: linear discriminant function analysis, molt location, southern Africa, stable isotopes, waterfowl movement, wetlands
Copyright Information: Copyright © American Ornithological Society 2019. All rights reserved.
Funders: Global Avian Influenza Network for Surveillance (GAINS), Wildlife Society, DST/NRF Centre of Excellence at the Percy FitzPatrick Institute, French Ministry of Foreign Affairs
Date Deposited: 11 Mar 2020 07:42
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050206 Environmental Monitoring @ 100%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960802 Coastal and Estuarine Flora, Fauna and Biodiversity @ 100%
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