Browsing by Author "Taylor, M"

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    Comparing internal and external drivers in the southern Benguela and the southern and northern Humbolt upwelling ecosystems
    (2008) Shannon, L J; Neira, S; Taylor, M
    Trophic models of three upwelling ecosystems, the southern Benguela (South African), southern Humboldt (Chilean) and northern Humboldt (Peruvian) systems, have been fitted to catch, abundance and fishing mortality time-series. Three drivers were considered during the model fitting: internal forcing by means of the trophic flow controls between the various interacting species groups, and two kinds of external forcing, namely fishing and the environment. The southern Benguela model was fitted to time-series data from 1978 to 2003, the southern Humboldt model to data from 1970 to 2004, and the northern Humboldt to data for a shorter period, 1995–2004. Fishing has been relatively carefully managed in the southern Benguela during the period modelled and previous studies found that most of the resource variability was attributed to internal trophodynamic forcing and to environmental forcing rather than to fishing. By comparison, fishing has been shown to have played a relatively major role in driving ecosystem changes observed in the southern and northern Humboldt models. Bearing in mind the different roles played by each of the drivers in these ecosystems, flow controls between interacting species groups, which improved the fits of the models, were compared across the three ecosystems to determine to what extent the three models supported the hypothesis that upwelling ecosystems function as wasp-waist systems. Secondly, environmental forcing was examined by searching for hypothetical forcing functions, affecting different levels of the foodweb, which improved the model fits. This was an attempt to start to uncover the processes that may be involved in linking the environment to observed ecosystem dynamics and changes in these upwelling ecosystems. Model results confirmed the important ecological role played by small pelagic fish in the studied upwelling ecosystems. For example, the fit of the southern Benguela model to time-series data of catch and abundance was similarly improved when anchovy/sardine–prey and anchovy/sardine–predator interactions were externally forced, supporting the wasp-waist hypothesis. In addition, although physical drivers and conditions may differ in their nature or merely their frequency and intensity between systems, and different fishing strategies operate in each of the three ecosystems, model results suggest that these effects are transferred through the ecosystems and manifest themselves as ecosystem changes and observed resource dynamics largely via interactions with small pelagic fish.
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    Overweight, obesity, underweight and stunting in female primary school learners in rural KwaZulu-Natal, South Africa
    (2013) Tathiah, N; Moodley, I; Mubaiwa, V; Denny, L; Taylor, M
    Background. Malnutrition substantially impacts the health outcomes of children. Globally, the childhood prevalence of overweight and obesity has increased, while underweight and stunting (though decreasing) continues to pose a major public health challenge. In low- to middle-income countries, a mixed pattern of over- and undernutrition (nutritional transition) can exist in communities. Objective. To describe the prevalence of malnutrition among female learners in the Nongoma and Ceza districts in Zululand, KwaZulu-Natal (KZN). Methods. We performed a secondary analysis of anthropometric data collected during the 2011 HPV Vaccination Demonstration Project. School health teams, comprising trained nurses, measured the height (in cm) and weight (in kg) of 963 female learners in 31 primary schools. Internationally accepted standardised measures were used as cut-offs for defining overweight, obesity, underweight and stunting. Results. We found evidence of both under- and overnutrition. Overall, 9% of female learners were overweight, 3.8% obese, 4% underweight and 9.2% stunted (using WHO/NCHS criteria). The highest levels of stunting were in the 11 - 12-year age groups, of underweight in the 10-year age group, of overweight and obesity in the 9 - 10-year age groups. Moreover, a proportion of underweight (17.4%), overweight (11.1%) and obese (22.9%) learners were also stunted. Conclusion. Our study describes the prevalence of overweight and obesity, wasting and stunting of female learners in KZN and suggests the presence of a nutritional transition in these rural communities; however, further studies are needed. Our findings emphasise the need for health promotion and education programs in schools.