4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
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Item The effects of resource variability on the demographic rates of black and white rhinoceroses(University of the Witwatersrand, Johannesburg, 2023) Ndlovu, Latoya; Marshal, JasonGiven the importance of rhino survival and reproduction to conservation goals, the aim of the study was to investigate the effects of resource variability on the demographic rates of black (Diceros bicornis) and white (Ceratotherium simum) rhinos at Lapalala Wilderness. I used historical rhino-monitoring, rainfall and vegetation greenness data to investigate the vital rates of two rhino populations. I investigated population demographics (mainly density, growth rates, age and sex structure) and survival using stratified Cox models. Black and white rhino density peaked at 0.06 rhinos/km2 and 0.2 rhinos/km2 , respectively during the study period and was below the estimated maximum density for suitable rhino reserves. Average growth rate for the black rhinos was 4.784%, which was almost half of the white rhino’s rate of 8.861%. The survival of both species was stage-specific, and rainfall effects were similar for both species and age groups as low amounts of rainfall, which likely represent decreased forage availability, were associated with increased mortality risk. Decreasing greenness was also associated with increased mortality except with white rhino calves, where mortality increased with greenness. I suggest that this case might have been caused by their nutritional requirements: most grasses lose nutritional value as the season progresses (i.e., represented as increases in greenness values and so reduced access to high quality forage might affect mom’s body condition and her ability to produce nutritious milk, consequently resulting in increased mortality rates of calves. I also investigated the reproductive phenology (mainly conception and birth timing, age at primiparity and inter calving intervals) and birth sex ratios in relation to sex allocation theories. White rhinos conceived and calved at an earlier age compared to the black rhinos; mean age at primiparity for white and black rhinos was 9.448 years (8.467, 10.43) and 11.724 years (10.52, 12.927), respectively. Conceptions for both species peaked during the wet season and were associated with periods of high forage availability; however, births were asynchronous and occurred throughout the year. Effects of rainfall and greenness on age at first conception differed between species; the odds of having their first calf increased with rainfall, EVI and NDVI for white rhinos but decreased with EVI and NDVI for the black rhinos. Increases in wet-season integrated greenness during conception periods might indicate a shorter period of access to high quality forage for the black rhinos. Age at primiparity increased with density for both species because population density increases competition for resources, potentially making it difficult for females to accumulate the body mass and energy reserves needed to reproduce. Inter-calving intervals increased with rainfall, supporting the idea that excessive amounts of rainfall might result in lower forage quality, which then affects maternal body condition. In conclusion, vital rates of black and white rhinos are associated with resource availability as a function of environmental stochasticity and density, which in turn affects productivity and performance as climate change results in more variable conditions.Item Social reproduction, labour markets, and economic change in South Africa(University of the Witwatersrand, Johannesburg, 2023) Francis, David Campbell; Valodia, ImraanThe South African rural economy, and its relationship to the industrial economic heartlands, has been the focus of study for many decades. In the 1970s, Harold Wolpe provided an incisive materialist analysis of apartheid. He argued that the rural economy served as a site of the reproduction of labour for capitalism in urban South Africa, thus ensuring a supply of cheap labour. His cheap labour thesis has formed the backbone of political economy analysis in South Africa ever since. But Wolpe, and other such as Mike Morris, who studied the relationship between the rural economy and the development of capitalism in South Africa, were largely unconcerned with the highly gendered nature of cheap labour, despite the fact that women were actively excluded from mining and the industrial economy by law, and played a critical role in the reproduction of life and labour in the Bantustans. Following the end of apartheid, the legal barriers preventing women from working in the main economy were dismantled, and women’s labour force participation rose rapidly. But this legal equality has not translated into substantive equality: women in rural areas continue to be significantly worse off economically than men. Unemployment rates are significantly higher for women, and they earn lower wages than men, even where they do the same work. Women continue to undertake far more unpaid work than men, and girl and women-headed households are more likely to live in poverty. Furthermore, despite well-developed literature on South Africa’s political economy, we know little about the productive and reproductive lives of rural women in contemporary South Africa. This thesis critically re-examines Wolpe for the 21st century by providing a materialist, gendered analysis of the economy of Agincourt, Mpumalanga, an area which remains on South Africa’s geographic and economic periphery. It shows how households in this part of rural South Africa are responding to the ways in which capitalism in South Africa has changed in the post-apartheid period. This thesis illuminates the important links between labour force participation, paid work, unpaid work, and livelihood strategies among households in the Agincourt area. It argues that focusing on the role of South Africa’s rural areas as sites of the reproduction of labour, as per the cheap labour thesis, ignores the highly gendered nature of social reproduction and its contribution to the reproduction of both labour and life. This thesis further contends that the role of South Africa’s rural areas cannot be investigated or theorised without a specifically gendered approach which includes women’s work in the analysis. It adds to our knowledge about an area of South Africa which is important in its own right. And Agincourt is also emblematic of the conceptual and methodological challenges of studying rural areas and their relationship with the economic 8 heartlands of urban South Africa in a way that does not marginalise the economic lives of women. It further contributes methodologically and epistemologically to studying the intersection of paid and unpaid work. It draws on a mixed-methods approach – a household survey of 600 households and 24 in-depth interviews – to investigate women’s economic lives in this marginalised place, and to re-examine the relationship between South Africa’s economic core and its periphery from an explicitly gendered perspectiv