Browsing by Author "Ndlovu, Mduduzi"

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    Environmental influences on moult and movement strategies in southern African waterfowl
    (2012) Ndlovu, Mduduzi; Cumming, Graeme S; Hockey, Phil A R
    Waterfowl annual life history events in north-temperate regions are driven primarily by predictable seasonal variations in temperature. In contrast, the spatio-temporal availability of adequate resources to waterfowl in the semi-arid regions of southern Africa is determined by rainfall which is extremely variable in timing and intensity. I studied the environmental influences on flight-feather moult and movement strategies of southern African waterfowl. Six duck species that are fairly common in most parts of South Africa were selected for the study, namely; Egyptian Geese, Alopochen aegyptiaca, Spur-winged Geese, Plectropterus gambensis, South African Shelducks, Tadorna cana, Yellow-billed Ducks, Anas undulata, Red-billed Teals, A. erythrorhyncha and Southern Pochards, Netta erythrophthalma. I chose two study sites to represent the extremes of environmental conditions in southern African, namely Barberspan (summer-rainfall region) and Strandfontein (temperate winter-rainfall region). I investigated the underlying responses of Afrotropical waterfowl to stochastic varying environmental conditions in southern Africa and the life-history strategies they have evolved to cope with this variability. The study also compares and contrasts the life-history strategies of southern hemisphere waterfowl with those of the northern hemisphere.
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    Linking avian communities and avian influenza ecology in southern Africa using epidemiological functional groups
    (BioMed Central, 2012-10-26) Caron, Alexandre; de Garine-Wichatitsky, Michel; Ndlovu, Mduduzi; Cumming, Graeme S
    The ecology of pathogens, and particularly their emergence in multi-host systems, is complex. New approaches are needed to reduce superficial complexities to a level that still allows scientists to analyse underlying and more fundamental processes. One promising approach for simplification is to use an epidemiological-function classification to describe ecological diversity in a way that relates directly to pathogen dynamics. In this article, we develop and apply the epidemiological functional group (EFG) concept to explore the relationships between wild bird communities and avian influenza virus (AIV) in three ecosystems in southern Africa. Using a two year dataset that combined bird counts and bimonthly sampling for AIV, we allocated each bird species to a set of EFGs that captured two overarching epidemiological functions: the capacity of species to maintain AIV in the system, and their potential to introduce the virus. Comparing AIV prevalence between EFGs suggested that the hypothesis that anseriforms (ducks) and charadriiforms (waders) drive AIV epidemiology cannot entirely explain the high prevalence observed in some EFGs. If anseriforms do play an important role in AIV dynamics in each of the three ecosystems, the role of other species in the local maintenance of AIV cannot be ruled out. The EFG concept thus helped us to identify gaps in knowledge and to highlight understudied bird groups that might play a role in AIV epidemiology. In general, the use of EFGs has potential for generating a range of valuable insights in epidemiology, just as functional group approaches have done in ecology.