ETD Collection

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/104


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    Land cover change detection analysis for the Atok area with special emphasis on chrome mining development
    (2021) Sethobya, Ramoshweu Melvin
    The main focus of this research study was to quantify temporal land cover changes (LCC) around the Atok area in Sekhukhune District, Limpopo Province, over a period of four years. The influence of chrome mining expansion on land cover changes was mapped using Sentinel 2 imageries acquired in 2016 and 2019 using the Maximum Likelihood Classifier (MLC) and Support Vector Machine (SVM) classification algorithms. Normalized difference vegetation index (NDVI) was used to establish correlation between the change analysis results with clas sification results. The overall accuracies of the 2016 and 2019 Sentinel-2 image classifications using the MLC were 83% (with kappa value of 0,77) and 80% (with kappa value of 0,75) respectively, while those of the SVM classifier were 84% (with a 0,78 kappa coefficient) and 81% (with a 0,76 kappa coefficient) respectively, showing that the SVM outperformed the MLC by a 1% margin. The chrome mining operations grew by 1,6% from an average of 2,3% in 2016 to 3,9% in 2019, which is an increase of 314.5 hectares over the period of four years. Vegetation cover decreased by an average of 3,3% (648,6 ha) during this period. A moderate increase of 3,8% was recorded for dry areas, owing to exposures due to stripping and open cast mining in the new chrome mining operations. Further analysis of land cover types revealed the inter-relations of the change scenarios between the chrome mining class and other land cover types available in the study area. NDVI results highlighted areas of increased dry soil exposures and areas with major losses in vegetation cover, which are attributable to development of new chrome mining oper ations. Mapping of land cover change using Sentinel-2 imageries has proven robust in effec tively highlighting the impact of chrome mining activities and its expansion on the local land scape quality and environmental degradation within the area.
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    Expecto patronum
    (2020) Edery, Kyle
    Our natural world is currently undergoing a drastic and radical transformation! Human agency has led to the erosion of the very foundations of our livelihoods, economies, food security, health and quality of life. Ecosystems, which form our life support systems and our safety nets are shrinking and collapsing. At the heart of this collapse are pollinators, such as butterflies and bees, key species responsible for maintaining these vital ecosystems, whose very existence is being threatened by human activity. This thesis depicts a series of explorations, re-defining the environment and surface needed for pollinators in this new age of man vs nature, before manifesting and putting forth the creation of a version of an artificial envi-ronment. This version of an artificial environment is presented as a solution to sustain and revive endangered pollinators and the degrading context of the proposed site.This thesis looks at how architecture, in its physicality, can not only assist eco-systems and pollinators in their fight for survival but also act as a catalyst for a process of awakening and awareness. The intervention proposed in this thesis aims to create a space that negotiates between the two worlds of pollinators and humans, at the intersection of the built form and the natural environment. In doing so, this will ensure a space that benefits both people and pollinators, at their respective scales. The design of this new surface / artificial environment aims to aid pollinators year-round both naturally and through artificial means, while also showcasing their contribution to human life and research to aid their survival. The thesis demonstrates the demise of nature, illustrating the impact humanity, as a species, has had and continues to have on the natural world, primarily on the lives of pollinators. A focus on the demise of pollinators is addressed, as their brink of extinction stresses a fundamental link between the two causes of collapse and how by saving pollinators, nature in turn can be revived. By doing the above, this thesis will advocate for the creation of an artificial environment as an effective solution to sustain and revive South Africa’s endangered pollinators
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    Fishing hub: establishing a sustainable fishing infrastructure as a catalyst for socio-economic development on Lake Malawi
    (2020) Yakobe, Andrew U
    Overfishing, habitat degradation, climate change and poor fish preservation infrastructure are the main factors that are leading to the depletion of fish species in Lake Malawi. Lake Malawi is of great significance because it is a World Heritage Site due its biodiversity, notably its various fish species. According to The Guardian Development Network (2018) “fish stocks in the Lake Malawi have dwindled by 90% over the past 20 years.” This is alarming because fishing is one of the main ways of sustaining human existence across Lake Malawi and extending into the inland settlements where fishing is a source of food, income, and recreation It is the author’s observation that the Department of Fisheries in Malawi together with various other institutions are struggling to resolve fish depletion and its negative impacts on impoverished lakeshore settlers’ livelihoods because of lack of adequate fishing infrastructure suitable for such sensitive regions that promote sustainable fishing practices around fishing villages. The absence of such facilities further threatens the extinction of the popular Chambo fish (Tilapia) which accounts for 1% of fish consumed from Lake Malawi (Malawi Government Economic Report, 2017). This research investigates and proposes a Fishing Hub which is a fish conservation facility centered on Chambo fish, which also addresses social, economic and ecological aspects that are at the core of fish depletion. It further explores the notion of regional and nature inspired design by interrogating the natural environment and existing built fabric along and around the lakeshore to produce a hybrid architectural language of balance; that is suitable to Lake Malawi as a response to building in sensitive ecosystems. The Fishing Hub is a sustainable ecosystem of water and land synergy that allows for fish reproduction and consumption whilst achieving socio-economic development on the lakeshore, at Nguwo fish landing site. The intervention formalizes the existing unregulated fish markets without taking away the agency of the locals, improve post-harvest infrastructure, aids to control water pollution, and most of promotes sustainable industrial fishing that also integrates collective small scale business networks of the community. This transformed space becomes a beacon of educative sustainable fishing practices that also gives an opportunity for tourists to experience the lakeshore culture. Inevitably this will become a harmonized ecosystem and a catalyst for socio-economic development on Lake Malawi.
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    Modeling the environmental niche of a South African fynbos endemic tree aloe, kumara plicatilis, and predicting impacts of climate change on the species' distribution
    (2017) Variawa, Tasneem
    Understanding why species occur where they do and, predicting where species might migrate to under different global change scenarios is an important aspect of biodiversity conservation. Regions that harbour high levels of species diversity and endemism arising from sharp local climatic and ecological gradients are highly susceptible to changing conditions. Kumara plicatilis is a tree aloe endemic to the Boland mountain ranges in the species-rich fynbos region in the Western Cape Province of South Africa. The species is currently listed as Least Concern as far as habitat degradation, population decline, invasive species and direct-use threats are concerned although impacts of anthropogenic climate change on this habitat specialist remain undocumented. This study used species distribution models to successfully classify the environmental niche of the species as well as delineate spatial patterns of probable occurrence and abundance based on this niche. In addition, models based on the IPCCs 2014 ‘best-case’ and ‘worst-case’ climate change scenarios provide projections of changes in the spatial occurrence patterns of Kumara plicatilis expected under conditions of shifting climates. Niche-based statistical analyses were further used to draw temporal comparisons between current and future projected ranges to ascertain the degree and properties of shared niche space now and in the future. Results indicate that suitable habitat conditions for the species distribution is irregularly spread around the central and southwestern fynbos region constrained by several climatic and biophysical variables including winter rainfall and temperature conditions as well as vegetation type. The species is expected to experience limited to severe declines in the area of suitable habitat available under mild and harsh climate change conditions, respectively. The patterns arising from these models are in line with the environmental niche measurements which show large degrees of overlap between current and future niche space of the species. These outcomes suggest that Kumara plicatilis displays traits of environmental niche conservatism where unsuitable climate and biophysical conditions can limit its geographic range and local extinction of populations can occur due to global change. Whilst the results of this study offer a useful and initial insight into the possible impacts of shifting climates on this species, outcomes from modeling should be interpreted with caution to reach the best management decisions and conservation action for this endemic species.