4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
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Item The Stratigraphy of the New Tuli Basin Fossil Sites in Zimbabwe(University of the Witwatersrand, Johannesburg, 2024-09) Zondo, Michel; Choiniere, Jonah; Broderick, Timothy; Munyikwa, DarlingtonThis thesis investigated new fossil-bearing outcrops of the Mpandi Formation of Zimbabwe, exposed at Sentinel Ranch in the Tuli Basin, at sites named “Wedding Hill “and “Pimwe Hill”. The Mpandi Formation exposures at Sentinel Ranch reveal strata that were deposited in fluvial environments that occasionally experienced flooding in otherwise usually dry and hot climatic conditions. These fluvial systems deposited facies that are mostly dominated by fine sediments and their facies have similarities with those found in the main Karoo Basin of South Africa. The use of borehole data helped establish the thickness of the Mpandi Formation and the explorable portion of the formation was estimated to be around 54 metres. Detrital zircons collected from main Sentinel outcrops were used to estimate the maximum depositional age of the sediments using inductively coupled plasma mass spectrometer (LA-ICPMS) methods. Although sparse, the youngest zircons in these samples yielded ages of 199.2 ± 5.1 Ma and 200.8 ± 5.8 Ma, with error bars suggesting maximum depositional ages in the earliest Jurassic or possibly the latest Triassic. A bonebed at the Wedding Hill site produced many postcranial bones of sauropodomorphs, including the articulated leg of a very large individual sauropodomorph, and the first theropod bones recorded from the Mpandi Formation at Sentinel. The discoveries improve our knowledge of the fauna diversity of the Mpandi Formation, permitting more accurate biostratigraphic correlation and enhancing our understanding of the Triassic- Jurassic interval.Item Taphonomy and palaeoecology of a monospecific microvertebrate bonebed: behavioural implications for the late Permian (Lopingian) parareptiles(University of the Witwatersrand, Johannesburg, 2024-06) Mukwevho, Lutendo; Choiniere, Jonah; Smith, RogerSociality in the vertebrate fossil record is a dynamic and fast-expanding area of research. Natural history observations of living animals are crucial for understanding and categorizing sociality, but these observations are not feasible for extinct species. Monotaxic bonebeds provide unique opportunities to conceptualize the social behaviours of these extinct animals. An unusual bonebed (SAM-PK-K11289) discovered in the uppermost Permian strata of the Balfour Formation, Karoo Supergroup, in the Eastern Cape presents a window into the sociality of Late Permian reptiles. The use of propagation phase-contrast synchrotron X-ray microcomputed tomography permitted the 3D reconstruction of skeletal elements in SAMPK-K11289, allowing the taxonomic identification of the individuals in the bonebed as most likely belonging to Owenetta. This is the largest aggregation of Owenetta individuals known to date, with a minimum number of 31, which are all very similar in body size. The ontogenetic profile of SAM-PK-K11289 was interpreted by analysing the size distribution of duplicate elements and by making comparisons with other Owenetta and procolophonid specimens. The specimens in the bonebed are all osteologically immature, indicating that they are juveniles. The bonebed occurs in a pedogenically modified ripple cross-laminated siltstone suggesting that a low-energy fluvial sedimentation likely contributed to the modification, disturbance and disarticulation of elements before the bonebed was buried at or very close to the death site. This bonebed provides novel information that directly challenges the popular belief that reptiles and their ancestors are non-social or asocial. Considering the overall circumstances of the bonebed, I hypothesize that Owenetta rubidgei juveniles were socially gregarious and this behaviour may have been induced or influenced by environmental changes during the early extinction phase of the end Permian mass extinction in the Karoo Basin.Item Metagenome sequencing of the lichen species Flavopunctelia flaventior and Parmotrema tinctorum from Gauteng, South Africa(University of the Witwatersrand, Johannesburg, 2024-06) Katane, Malebogo Dimpho; Botes, Angela; De Maayer, PieterLichens are defined as a mutualistic association between fungi (mycobiont) and an algal and/or cyanobacterial photobiont. Increasing evidence suggests that lichens comprise more diverse microorganisms than initially thought, where lichens represent an interaction between archaea, bacteria, filamentous fungi, green algae, yeasts, and viruses. Not many comprehensive studies have been done of South African lichen species. The present study employed metagenome sequencing to investigate the lichen microbiomes of Flavopunctelia flaventior and Parmotrema tinctorum sampled from Bryanston, Gauteng province, South Africa. Furthermore, the roles played by the members of the lichen microbiome within symbioses were also studied by functionally annotating the assembled metagenomes of the two lichen species. This study sets the groundwork for future studies on South African lichen species. In Chapter 1, an extensive literature review on lichens, their ecology, taxonomy and biology is discussed. Furthermore, it delves into the existence and shape of the microbiome beyond the mycobiont and the photobiont. Additionally, possible roles that the lichen microbiome may play in sustaining the lichen symbiosis is also discussed. In Chapter 2, the metagenomes of two lichen species were sequenced, the quality of the reads were assessed, and taxonomic classification was performed to elucidate the composition of microorganisms associated with each lichen species. Both microbiomes were dominated by bacteria, with limited fungi, viruses, and archaea. The majority of the identified phyla and genera were found to be common between the two lichen species. Similarities in the core microbiome was accounted for by the fact that F. flaventior and P. tinctorum were sampled from the same location and they are both members of the Parmeliaceae family. In Chapter 3, the metagenomic reads were assembled and functionally annotated using various bioinformatics tools. We demonstrate that the members of the lichen microbiome are involved in the cycling of nutrients such as carbon and nitrogen. We also found differences in carbon fixation pathways, which were attributed to the accessory microbiome. Finally, a summary highlights key results and recommendations on future work that could be undertaken to further provide insight into biological pathways essential to sustain the lichen symbiosis.Item Exploring the Structure, Function and Stability of Glutathione Transferases Engineered from Intra- and Inter-class Consensus Sequences: How Forgiving is Nature?(University of the Witwatersrand, Johannesburg, 2024-10) Mulenga, Thabelo; Achilonu, Ikechukwu; Sayed, YasienProtein folding is an enigmatic biochemical process that is foundational to the structural and functional requirements of a cell. The problem of protein folding, in a nutshell, concerns itself with the rate of protein folding as well as the conversion of amino acids from a linear sequence to a fully folded structure. This problem is partly answered by the existence of folding pathways. The folding funnel was conceptualised as a depiction of folding pathways, and it is a framework that illustrates that native proteins naturally favour the lowest energy state, encountering kinetic and thermodynamic barriers as they fold. Consensus protein design, based on this understanding, aims to: (1) enhance stability and (2) navigate the pitfalls of folding by modifying the folding funnel of a protein. This approach can also shed light on the significance of evolutionarily conserved residues. In this study, consensus protein mutants were generated for the Alpha and Mu glutathione transferases (GSTs) classes. The consensus proteins were then benchmarked against the parental proteins that were chosen (hGSTA1-1 and hGSTM1-1). The Alpha consensus mutant had 11 consensus mutations, including a notable M50L mutation, which affects the dynamic behaviour of helices α2 and α9, while the Mu consensus mutant had 13 unique mutations. Protein production and purification showed that the Mu consensus mutant had larger and purer yields. Data from far-UV circular dichroism studies and root-mean-squared-fluctuation (RMSF) from molecular dynamics (MD) simulations showed that the secondary structural components of the Alpha and Mu proteins remained largely the same, although the Alpha consensus mutant displayed a far lower molar residue ellipticity reading than its wildtype counterpart, indicating the disruption of secondary structural elements, likely caused by the M50L mutation. The ANS binding results showed that the M50L mutation in the Alpha consensus protein caused an increase in exposure of the surface area of the H-site, while the Mu consensus protein had a decrease in the solvent accessibility of its H-site. Thermal shift assay results indicated the consensus proteins had increased thermal stability. Enzyme kinetics results showed that the functionality of the proteins was severely diminished in the consensus mutants, particularly the Alpha consensus mutant. MD simulation results showed that there was an overall increase in the rigidity and compactness of the consensus mutant proteins, further affirming the improvement of thermal stability, while signalling the loss in functionality. The results produced herein have the potential to facilitate the proliferation of engineered GSTs for biotechnological applications that require proteins with an increased half-life and greater stability.Item Natural resource use and environmental perceptions in different types of rural villages in Bushbuckridge, South Africa(University of the Witwatersrand, Johannesburg, 2024-09) Mbedzi, Mary Emma; Twine, WayneHouseholds in rural communities in developing countries rely on natural resources that contribute to income generation, food, medicine, cooking energy, and act as livelihood safety nets. Levels of dependency vary between households within communities due to factors such as wealth status and household size. However, less is known about differences in household resource use between communities within an area. Environmental awareness, values, and preferences are shaped by various factors including, local context. Thus, perceptions of the environment and natural resources, and changes in these are likely to vary between communities. This study aimed to compare the levels of natural resource use and environmental perceptions across village types and determine if there is any relationship between the level of natural resource use and environmental perceptions across village types in the Bushbuckridge Local Municipality in the Mpumalanga province, South Africa. Village types were defined and categorised based on their size, socio-economic factors, access to basic services, connectedness, and remoteness. The level of natural resource use was analysed using existing data from a survey of 491 households across 12 villages located in the Agincourt Health and Demographic Surveillance System (AHDSS) site. This included data on the use, collection, buying, and selling of a range of natural resources used locally (e.g., wild foods, firewood, and medicinal plants), annual consumptions, ownership of resources made from natural resources, and livestock (cattle) ownership. The survey included questions on respondents’ perception of the change in the supply of natural resources over the past 5 years (2016-2021) before the survey. Focus group discussions were conducted in 10 of the study villages asking participants their perception of the changes in the environment and the causes thereof, the importance of the natural environment, natural resources used for their daily needs, income generation, their culture, as well as the changes in availability of natural resources and impacts on their livelihoods. The study villages were classified according to a village typology that had been developed for the AHDSS study site, based on factors such as connectedness, access to amenities and services, and the proportion of Mozambican refugee households. ANOVA and Kruskal Wallis tests were used for continual data, while the Chi-squared test was used for categorical data to test for significant differences across village types in the quantitative part of the study. For qualitative, responses of participants from each village were recorded and grouped into village types, and an overall picture of the perception of natural resources that participants used was developed using the focus group schedule. Similarities and differences in natural resources between villages were assessed by grouping widely and less used resources by villages and village types. There was no significant difference (p>0.05) in the mean prevalence of use, collection, buying, and selling of natural resources, or annual consumption of natural resources across villages and village types. Households in better-serviced villages owned more products from natural resources and were to greater extent, likely to own livestock than poorly-serviced villages. As to environmental perceptions, more respondents in the poorly serviced village types (refugee settlements (RS) and underdeveloped communities (UC)) perceived a decrease in the supply of natural resources than better-serviced village types (established communities (EC) and central communities (CC)). Participants in focus group discussions also noted a decrease in the supply of natural resources across all villages and village types. There was a relationship between village types, natural resource use, and perceptions of change in natural resource availability. Established communities correlated with a higher number of resources perceived as decreasing and central communities were associated with higher cattle ownership. Underdeveloped communities and refugee settlements were associated with a higher number of resources used/owned, a higher number of resources used often (more than 4 times a month), and a higher number of resources sold, and buying firewood. Natural resources were more highly used in, better-serviced village types (central communities, and established communities), than in poorly-serviced village types (underdeveloped communities, and refugee settlements), which was unexpected. However, there were quite a few proxies such as the collection and selling of resources, which were used that did not help back up these findings which could explain the unexpected results. Most respondents in remote and poorly-serviced village types perceived a change in the supply of natural resources, the greatest decrease being in the supply of natural resources. This is associated with awareness of the value of the environment and high reliance on natural resources for these poorly-serviced village types. This study suggests that differences exist in resource use patterns between villages, even in the same area. However, village characteristics were not a good predictor of all aspects of resource use. Changes in proxies of resource utilization and re-evaluating the existing village typology would be useful for further studies.Item Evaluating the impact of land use activities in and around Lake Kariba on the presence and levels of anions and cations in the water body(University of the Witwatersrand, Johannesburg, 2024-09) Monyai, Mokgaetji Andelina; Chimuka, Luke; Tutu, Hlanganani; Cukrowska, Ewa; Richards, Heidi L.Huge seas, lakes, and rivers come to mind when we think of surface water. Surface water is vulnerable to water pollution, with consequential repercussions for the well-being of both human and aquatic environments. Furthermore, the diminishing levels of oxygen have a profound effect on the natural ecological equilibrium within river and lake ecosystems. Lake Kariba, situated in the Southern African region, is a vital freshwater ecosystem supporting local communities, wildlife, and regional economies. However, it faces threats from human activities and erratic weather. This study investigated the influence of land use activities in and around Lake Kariba on water composition and the concentration of anions and cations. The research employed a combination of field surveys and laboratory experiments to identify potential sources of ions. Sixty-nine (69) water samples (53 downstream and 16 upstream) were collected during different seasons in October 2021, July 2022 and April 2023. The Ion Chromatography, Inductively Coupled Plasma equipped with Optical Emission and Mass Spectroscopy detectors were used to concentrations of various anions (Fˉ, Clˉ, NO3ˉ, SO4 2ˉ, and PO4 3ˉ) and cations (Ca, K, Mg, Na, Si, Al, Cr, Fe, Mn, As, Cu, Ni, Ti, and Zn) respectively. Acidic water was notably observed upstream in two sampling areas, namely the Malasha and Kanzinze rivers. The Malasha River exhibited pH levels ranging from 3.71 to 4.81, while the Kanzinze River showed a pH of 6.01. The electrical conductivity (EC) for Malasha ranged from 1035 to 1484 µS/cm, whereas for Kanzinze, it measured 878.0 µS/cm. These areas exhibited significantly elevated levels of both anions and cations. In the Kanzinze River, the detected concentrations showed the following descending order: SO4 2ˉ> Clˉ > NO3ˉ> Fˉ> PO4 3ˉ (anions); Ca > Mg > Na > K > Si > Fe > Al > Zn > Cu > Mn > Ni > Cr > Ti > As (cations). Conversely, the Malasha River, exhibited the following order for anions: SO4 2ˉ > Clˉ > NO3 ˉ > Fˉ > PO4 3ˉ, and for cations: Ca > Fe > Mg > Na > Si > K > Al > Mn > Zn > Cr > Cu> Ni > Ti > As. The significant presence of SO4 2- and NO3 - indicates that human activities and agricultural practices in certain areas of Lake Kariba's catchment can have a considerable impact on the lake's water quality. Despite this, the corresponding Water Quality Index (WQI) indicated that the water quality from Kanzinze and Malasha rivers was unsuitable for drinking purposes. The findings revealed variations in ions concentration at different sampling points, with discernible patterns corresponding to specific land use types, such as mining in the upstream that elevated the levels of SO4 2- and some heavy metals and also NO3 - levels in the downstream due to commercial cage fish farming. Statistical analysis showed significant downstream variations (p < 0.05) in water chemistry parameters related to land use, while upstream areas exhibited no significant differences (p > 0.05). Water quality index ranged from 13.1 to 230.0, categorizing water quality from "excellent" to "very poor." The study underscores the complex interplay between land use activities and water chemistry in Lake Kariba, emphasizing downstream impacts. These findings contribute valuable insights for sustainable management and conservation efforts in the region, considering the dynamic nature of the ecosystem and potential threats posed by anthropogenic activities. Continuous monitoring and mitigation strategies are crucial to reserving the ecological balance of Lake Kariba and safeguarding the well-being of its surrounding communities and wildlife.Item Hydrometallurgical extraction of metals from secondary resources using various reagents(University of the Witwatersrand, Johannesburg, 2024-04) Teimouri, Samaneh; Billing, Caren; Potgieter, HermanThe advancement and widespread applications of metals in the modern world have led to a growing demand which outstrips their supply. This has resulted in a vital need for recovering precious and critical metals from waste materials, known as secondary resources. Recovering precious, critical and heavy metals not only improves the circularity of metals, but also minimises the deleterious effects of waste materials on the environment. To achieve this crucial aim, research in this thesis focuses on improving gold (Au) yield by finding different ways for pretreatment to break down pyrite, the predominant sulfidic mineral that encapsulates gold in mine tailings. In addition, the research focuses on extracting critical metals such as indium (In) and gallium (Ga) from industrial waste, in this case electric arc furnace dust (EAFD). The results achieved in this research are presented in five publications as explained in brief below: The dissolution of pyrite – the predominant host mineral encapsulating gold – to improve gold extraction from mine tailings was studied in a nitric acid (HNO3) solution. The study showed that when the concentration of HNO3 is above 2 M, it acts as a powerful acid and oxidant to break down the pyrite structure, while simultaneously exposing the enclosed gold through oxidative dissolution. The conducted experiments confirmed that within 2 h, 3 M HNO3 effectively dissolved 95% of FeS2 to release the remaining gold in pyrite at 75 °C. The kinetics of pyrite dissolution was also examined in the temperature range of 25 to 85 °C. The results indicated that the mixed controlled model (1/3Ln (1–X)+[(1–X)–1/3–1)] = k.t, where X is the fractional conversion, k the apparent reaction rate constant, and t leaching time) describing the interfacial transfer and diffusion was governing the kinetics of pyrite dissolution in nitric acid. The activation energy required at low temperatures (25-45 °C) was 145.2 kJ/mol and it reduced at higher temperatures (55-85 °C) to 44.3 kJ/mol. Therefore, nitric acid pretreatment is an effective method for mine tailings containing pyrite with enclosed gold. Nitric acid can be recovered in an eco-friendly manner by capturing the emission of NOx gases from the nitric acid decomposition and can be economically attractive when regenerating the starting acid/oxidant (see publication: “The Kinetics of Pyrite Dissolution in Nitric Acid Solution”). To gain insight into the dissolution of minerals encapsulating gold, such as pyrite and chalcopyrite, an electrochemical study was conducted in nitric acid media using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV scans were measured to identify the oxidation-reduction peaks for pyrite and chalcopyrite. Based on the corresponding CV scans and visual observations, anodic and cathodic reactions for oxidised and reduced species were deduced for each identified peak which occurs at a specific potential. An EIS study was then conducted at the particular oxidative potentials, to gain further indications on the relevant reactions, hence providing supporting evidence of the dissolution mechanism. The EIS study at low potential (i.e. 0.5 V vs Ag/AgCl (3 M KCl) reference electrode) showed that the dissolution reaction was controlled by a diffusion process due to the accumulation of certain species, i.e. Fe(OH)3 and S0, on the pyrite electrode, and Cu1-xFe1-yS2-z, CuS2, and S0 in the case of chalcopyrite. This was confirmed in the EIS curve through the appearance of the linear Warburg diffusion effect. Increasing the potential beyond 0.7 V leads to reactions at which the previously formed species covering the surface of the electrodes and causing a diffusion barrier, oxidised further converting them to soluble species. This was reinforced by the omission of Warburg-like effects in the EIS data (see publication: “A comparision of the Electrochemical Oxidative Dissolution of Pyrite and Chalcopyrite in Diluted Nitric Acid Solution”). Due to environmental awareness, neoteric eco-friendly solvents like ionic liquids (ILs) and deep eutectic solvents (DESs), which can be used as alternatives to conventional leaching reagents for recovering metals, are gaining increasing attention among researchers. Hence, a new hydrometallurgical method using ILs to extract Zn, In, and Ga, along with Fe as a common impurity from EAFD, that was spiked with 5% of both In and Ga, was examined. EAFD is a valuable metal containing waste generated in significant amounts during the process of steelmaking from iron scrap material in an electric arc furnace. With critical metal recovery as the main goal, two ILs: [Bmim+HSO4–] and [Bmim+Cl–], were studied in conjunction with three oxidants Fe2(SO4)3, KMnO4, and H2O2, to determine which IL and oxidant combination performs best for extracting the target metals. Following the initial tests, the influence of parameters such as the IL concentration, oxidant concentration, solid-to-liquid ratio (S/L), time, and temperature were optimised to achieve the maximum extraction of the target metals. Results from a series of experiments found the optimum condition to be; 50 ml 30% v/v [Bmim+HSO4-], 1 g of Fe2(SO4)3 oxidant (2%), S/L ratio of 1/20, at 85 °C for 240 min leaching time, resulting in extractions of 92.7% Zn, 80.2% Fe, 97.4% In, and 17.03% Ga. The dissolution kinetics of the studied metals over a temperature range of 55–85 °C was diffusion-controlled (see publication: “A New Hydrometallurgical Process for Metal Extraction from Electric Arc Furnace Dust Using Ionic Liquids”). Environmental and safety concerns about traditional methods for gold extraction, and the potential volume of enclosed gold in mine tailings in sulfidic minerals (i.e. pyrite), were the motivations to find effective, efficient and ecologically benign ways to break down the pyrite structure to expose the locked gold to improve its extraction. Hence, the feasibility of the dissolution of pyrite was studied in a deep eutectic solvent (DES) as a novel solvent. DESs are an analogue of ILs, which are gaining increasing attention as a potential solvent with eco-friendly features. Therefore, the viability of pyrite dissolution in a DES containing choline chloride – a quaternary ammonium salt [(CH3)3NCH2CH2OH]+Cl−] – and ethylene glycol [HO-CH2-CH2-OH], named ethaline, was examined both theoretically through density functional theory (DFT) calculations and experimentally. DFT calculations determined whether Cl– and/or [C2H4O2] 2−, the two ligands provided by ethaline, can make the most probable and stable complex with Fe2+ and/or Fe3+. To do so, the reaction Gibbs free energies (-G) for possible complexes that Cl– and [C2H4O2] 2− can form with Fe were calculated. In addition, the energy gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO gap) were considered. Among the proposed complexes, the tetrahedral complex [Fe(C2H4O2)2]−, with Fe3+ chelation taking place through the O-donors of the ligand [C2H4O2]2−, ad the lowest -G (–71.4 eV) indicating the simultaneous formation of the complex, as well as the largest HOMO LUMO gap (1.3 eV) specifying the most stable complex. For experimental evaluation, the effect of the pH of the ethaline solvent mixed with hydrogen peroxide (H2O2) oxidant, and the different S/L ratios on Fe extraction (indicating pyrite dissolution) were examined. The results show that a pH of 8 provides the desired condition at which ethylene glycol is deprotonated to [C2H4O2]2−, was the favorable ligand for Fe complexation. It was found that the S/L ratio of 1/20 was optimal and achieved 23.7% Fe extraction. The theoretical and experimental work correlated in indicating [C2H4O2]2 − as the favourable ligand. However, the ethaline solvent as the leaching solution did not achieve adequate Fe extraction, as it did not succeed in properly breaking down pyrite to expose the locked gold (see publication: “The Feasibility of Pyrite Dissolution in a Deep Eutectic Solvent Ethaline: Experimental and Theoretical Study”). DFT modelling was also applied to theoretically calculate the possibility of the extraction of In and Ga, in the IL medium. To investigate this aim, three imidazolium-based ILs, namely [Bmim+HSO4–], [Bmim+Cl–], and [Bmim+NO3–] were selected for DFT calculations. They all have the same cationic part [Bmim+], but different anionic parts, i.e. [SO42–], [Cl–], and [NO3–], which are similar to the most commonly used mineral acids H2SO4, HCl, and HNO3, respectively. The -G for different complexes were calculated to determine which of the available ligands, i.e. sulfate (SO42–), chloride (Cl–), and nitrate (NO3–), provided by each IL most likely form the most stable complex with In and Ga. The obtained values for -G confirm that IL [Bmim+HSO4–], owing to the [SO42–] O-donor ligand, resulted in the dimer complexes of [In2(SO4)3] and [Ga2(SO4)3] having the lowest G and the largest HOMO-LUMO gap, indicating the most probable and stable complexes (see publication: “Indium and Gallium Extraction Using Ionic liquids: Experimental and Theoretical Study”)Item “Artful Sustainability” Inquiry into Urban Waste and Public Space Practices: a Case Study of Riverside View Mega City, Johannesburg(University of the Witwatersrand, Johannesburg, 2024) Mantshoane, Trevor; Charlton, SarahThe UN-Habitat (2021a, p. 29) has been spearheading efforts at ensuring that “placemaking institutionalizes the role of art and culture to achieve a lasting sense of place for [communities]” as per the SDG 11 agenda. Place-making foregrounds the central role of communities in ensuring quality and liveable public spaces often through arts-led interventions. To date, little research exists on how this global place-making agenda is faring at the neighbourhood level. Even less studied are the arts and cultural (ecosystem) services of public space and the impact of waste on people’s ability to benefit from these services. Against the global place-making agenda, this research artistically interrogates the eco-cultural dimensions of sustainability issues of waste and public spaces. It does this through a case study of Riverside View Mega City, Johannesburg (South Africa) This qualitative research study uses a case study strategy and draws on a range of practices broadly associated with the arts-based and practice- based methods. The study utilises a set of methodological tools like drawings, written and photo diaries to gain a window into the resident participants’ embodied experiences of waste and public space. In all, the research finds that waste malpractices have a disruptive impact on the residents’ ability to benefit from the eco-cultural services of public spaces in Riverside View Mega City. Consequently, public spaces are generally perceived and experienced negatively, although this is not uniform across all sections of the settlement. Moreover, efforts at institutionalising the arts and culture through place-making interventions remain ambiguous with little apparent relevance to the everyday sustainability issue of waste and public spaces.Item Evaluating the state’s response to flooding disasters: the case of deelpan village emergency housing(University of the Witwatersrand, Johannesburg, 2024) Rirhandzu, ChumaOver the past few years, South Africa has been struggling with managing flooding episodes. From a housing point of view, one then worries about the living conditions of the poor people who do not have the necessary resources to recover from the effects of the disaster, like the people of Deelpan Village in the North West province. To obtain data for this research, I analysed secondary data in relation to disaster management, housing, and planning accessed from government websites. I also conducted a total of 18 semi-structured interviews with the officials and community representatives who were actively involved in the Deelpan Village emergency housing project. This study revealed that the people of Deelpan preferred permanent housing structures over temporary solutions; hence, the Temporary Residential Units have not been provided. The study concluded that the Deelpan residents rejected TRUs for permanent structures due to fear of state failure. Three years after the 2021 flooding, no housing support has been provided by the state, indicating a lack of resources to handle disasters.Item Surface water dependencies and activity patterns of mammalian herbivores in South Africa(University of the Witwatersrand, Johannesburg, 2024-10) Padayachy, Janiel; Hetem, Robyn; Strauss, Willem Maartin; Venter, JanAn increase in aridity in Africa may make water availability more variable, thus understanding how animals respond to these conditions is important for future wildlife management and conservation. However, mammalian herbivores with varying water requirements may respond differently to changes in water availability and predation. Using camera trap data, I analysed the spatial distribution relative to surface water sources and the 24-hour activity of 16 mammalian herbivores across 10 sites in South Africa. As expected, water dependent herbivores were generally closer to water, but only at sites where lions were absent. Herbivores with low water requirements were more nocturnal, potentially reducing water required to cool themselves evaporatively when active during the heat of the day. But that nocturnal activity was reduced when lions were present, likely reducing predation risk, increasing water requirements to dissipate heat and forcing herbivores to remain close to water. Nocturnal activity increased with body size in mixed-feeders and grazers, but decreased with body size in browsers, potentially reflecting more time spent foraging by large browsers. Using a novel approach of multistate diel occupancy models I showed that herbivores were generally active during both the day and night, and that the presence of lions impacted occupancy of preferred prey species (blue wildebeest, gemsbok and zebra). Diel occupancy of water-dependent prey (blue wildebeest) was influenced by an interaction between lion presence and distance to water sources. Thus environmental factors as well as physiological and morphological features affected the timing of activity and spatial distribution of several mammalian herbivore species in South African wildlife areas, which should be considered for future research and management of these species.