Mineralogy and geochemistry of permian black shales and carbonate concretions in the lower ECCA formations of the Steytlerville- Jansenville area, southern Karoo basin
- Authors: Maake, Laurentias Tebatso
- Date: 2019
- Subjects: Black shales -- South Africa -- Jansenville , Geochemistry Chemistry, Analytic Mineralogy -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/40643 , vital:36206
- Description: The Lower Permian Ecca Group formations of the Karoo Basin of South Africa have recently been identified as a target for shale gas exploration. These units, named the Prince Albert, Whitehill and Collingham formations, comprise organic-rich shales with occasional associated carbonate deposits, and siliciclastic facies. Mineralogical and geochemical investigations were conducted into carbonaceous shales and associated sedimentary rocks in the Jansenville area of the southern Karoo Basin with the ultimate aim to decipher the paleoenvironment and post-depositional conditions of these shales and their associated features such as prominent intra-formational carbonate deposits. Sediments of the main Karoo Basin were deposited from ~350 Ma to ~182 Ma, the end of sedimentation being marked by eruption of basaltic lava. This period, which began with the Dwyka continental glaciation, included tectonism of the Cape Fold Belt, the end-Permian mass extinction at ~250 Ma, and major intrusion of dolerite associated with the lavas of the Karoo Large Igneous Province. Subsequent to this, the basin experienced faulting associated with Gondwana breakup, uplift and intrusion of small volume kimberlite and melilite magmas, and erosion resulting in formation of a major escarpment. Each episode was imprinted upon the Karoo rocks and to a greater or lesser extent erases the signature of older episodes. To decipher the depositional paleoenvironment and post-depositional conditions of the black shales and the dolomite concretions posed a challenge due to deformation, orogeny, metamorphism, and weathering and erosion. Therefore, deep borehole core-logging and sampling was generally preferred over surface fieldwork, and trace elements backed up by scanning electron microscopy-based petrography was the method most relied upon to decipher the redox conditions of the black shales and the intra-formational carbonates. Relevant sections from three SOEKOR boreholes SP1/69, AB1/65 and QU1/65 were logged and carbonate concretions localities studied in four field locations. Samples collected from the core and field localities were prepared for thin section optical, SEM petrographical analysis, mineral identification, modal estimation by XRD, major, and trace element analysis by XRF and Laser Ablation-ICPMS, and acid leaching of a sample subset to determine the degree of pyritization (DOP). Logging of the SOEKOR boreholes indicates that in the western part of the basin all three lower Ecca formations, namely the Prince Albert, Whitehill and Collingham, overlie the tillites of the Dwyka Group, whereas near East London only the Whitehill Formation is present. Dwyka diamictites occur in all the studied boreholes overlying the crystalline basement in AB 1/65 and QU 1/65 boreholes whereas in the SP 1/69 the tillites rest above the quartzite of Witteberg Group of the Cape Supergroup. The shale consists of discontinuous, wavy and straight parallel laminae. Parallel, discontinuous and elongate micro-lenses of very fine-grained quartz are diagnostic and suggest late-stage silicification. Thin laminae of black shale are interlaminated with grey clay. The black shales are composed of quartz and clay minerals (illite and chlorite) as the major crystalline minerals with minor quantities of sulphides and heavy minerals. Organic matter occurs as unstructured, anhedral patches of amorphous material. It contains abundant small (~10nm) and less common larger (~100 nm) pores of subsphaeroidal shape. Carbonates occur as cementation and concretions. Heavy minerals identified by SEM include detrital zircon, thorite, titanite, authigenic fluorite, galena, sphene, and sphalerite and apatite, monazite and epidote-group minerals that appear to be of later stage metamorphic origin, some a product of hydrothermal feldspar alteration. Zircon and monazite show evidence of partial corrosion and/or new overgrowth. Titanite occurs in greater abundance in the SP1/69 section than other boreholes, where it exhibits a porphyroblastic texture suggesting secondary growth. These features all suggest modification of detrital minerals by metamorphic fluids and therefore some possible modification of bulk geochemical composition. Pyrite is abundant, commonly occurring as framboidal and occasional euhedral grains. Pyrite-bearing, calcite veins are common in the Whitehill Formation. Some pyrite is metamorphosed to pyrrhotite in the shales adjacent to dolerite intrusions. The carbonate deposits in the lower Ecca occur mostly as large concretions of 0.5-2.5 m in diameter at intensely faulted areas, and as laterally continuous beds at less intensely faulted areas. They consist of dominant dolomite with calcite (differentiated by thin section staining) and minor associated quartz veins, and appear to have formed in an early diagenetic stage of the black shale. Five different dolomite-rock textures were identified indicating varying crystal growth conditions. Calcite cementation types accompany these dolomite textures. The major types include mosaic, sparry and bladed/prismatic calcite cement. Calcite occurs mainly as cement in pores and grain replacement, as well as crudely radial septerian veins. XRD indicates that the carbonate concretions are made up of more than 90% dolomite, especially within the intensely folded areas. The remaining 10% consist of post-depositional quartz veins and secondary calcite associated with the quartz veins. In one locality (VAAL) the carbonate samples are dominates by bladed/prismatic calcite. The black shales in this study have similar geochemical signature to previously analysed samples from the Karoo Basin and to black shales worldwide. The geochemical signature results from the combined input of detrital sedimentary materials as well as enrichment or depletions acquired from pore water, biological activity and during diagenesis. Positive correlation of K2O, Na2O with Al2O3 suggests control by the detrital contribution. CaO and P2O5, have a negative correlation with Al2O3 suggesting a biogenic source. Elemental ratios suggest that the sediments derive from felsic source rock, most likely Cape Supergroup and underlying crystalline basement. These shales exhibit different degrees of trace-element enrichment relative to global average shale, the approximate order being Pb> V> Zn> Cr> Cu> Co > Ni. Assessment of selected trace elements, V/(V+Ni), V/Cr, Ni/Co and EF Mn ratios describes the paleoenvironment of these sediments to have been partially oxygenated before sulphate reduction interface. The pyrite size distribution, DOP, Fe and S correlation points to an organic matter limited environment, where the main sulphur sink is pyrite rather than organic matter. The DOP and Fe/Al indicated that the sediments became anoxic at the sediment-water interface (early diagenetic stages). V/Cr assessment of the dolomite concretions suggested partially oxygenated environment corresponding to the black shale deposition. The occurrence of concretions at the base of the Whitehill Formation, which has the highest TOC content of 14% compared to other associated formations, is evidence that organic matter preservation was important to their origins. The parameters used here to assess the redox conditions of the black shales and the dolomite concretions in this region of the Karoo Basin suggest a normal marine redox environment, rather than the anoxic Black Sea-type environment. The conditions that affected the lower Ecca formations varied from semi-oxygenated to oxygen depletion environment. The oxygen depletion environment occurred during the deposition of the Whitehill Formation of which organic matter preservation was favoured..
- Full Text:
- Date Issued: 2019
- Authors: Maake, Laurentias Tebatso
- Date: 2019
- Subjects: Black shales -- South Africa -- Jansenville , Geochemistry Chemistry, Analytic Mineralogy -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/40643 , vital:36206
- Description: The Lower Permian Ecca Group formations of the Karoo Basin of South Africa have recently been identified as a target for shale gas exploration. These units, named the Prince Albert, Whitehill and Collingham formations, comprise organic-rich shales with occasional associated carbonate deposits, and siliciclastic facies. Mineralogical and geochemical investigations were conducted into carbonaceous shales and associated sedimentary rocks in the Jansenville area of the southern Karoo Basin with the ultimate aim to decipher the paleoenvironment and post-depositional conditions of these shales and their associated features such as prominent intra-formational carbonate deposits. Sediments of the main Karoo Basin were deposited from ~350 Ma to ~182 Ma, the end of sedimentation being marked by eruption of basaltic lava. This period, which began with the Dwyka continental glaciation, included tectonism of the Cape Fold Belt, the end-Permian mass extinction at ~250 Ma, and major intrusion of dolerite associated with the lavas of the Karoo Large Igneous Province. Subsequent to this, the basin experienced faulting associated with Gondwana breakup, uplift and intrusion of small volume kimberlite and melilite magmas, and erosion resulting in formation of a major escarpment. Each episode was imprinted upon the Karoo rocks and to a greater or lesser extent erases the signature of older episodes. To decipher the depositional paleoenvironment and post-depositional conditions of the black shales and the dolomite concretions posed a challenge due to deformation, orogeny, metamorphism, and weathering and erosion. Therefore, deep borehole core-logging and sampling was generally preferred over surface fieldwork, and trace elements backed up by scanning electron microscopy-based petrography was the method most relied upon to decipher the redox conditions of the black shales and the intra-formational carbonates. Relevant sections from three SOEKOR boreholes SP1/69, AB1/65 and QU1/65 were logged and carbonate concretions localities studied in four field locations. Samples collected from the core and field localities were prepared for thin section optical, SEM petrographical analysis, mineral identification, modal estimation by XRD, major, and trace element analysis by XRF and Laser Ablation-ICPMS, and acid leaching of a sample subset to determine the degree of pyritization (DOP). Logging of the SOEKOR boreholes indicates that in the western part of the basin all three lower Ecca formations, namely the Prince Albert, Whitehill and Collingham, overlie the tillites of the Dwyka Group, whereas near East London only the Whitehill Formation is present. Dwyka diamictites occur in all the studied boreholes overlying the crystalline basement in AB 1/65 and QU 1/65 boreholes whereas in the SP 1/69 the tillites rest above the quartzite of Witteberg Group of the Cape Supergroup. The shale consists of discontinuous, wavy and straight parallel laminae. Parallel, discontinuous and elongate micro-lenses of very fine-grained quartz are diagnostic and suggest late-stage silicification. Thin laminae of black shale are interlaminated with grey clay. The black shales are composed of quartz and clay minerals (illite and chlorite) as the major crystalline minerals with minor quantities of sulphides and heavy minerals. Organic matter occurs as unstructured, anhedral patches of amorphous material. It contains abundant small (~10nm) and less common larger (~100 nm) pores of subsphaeroidal shape. Carbonates occur as cementation and concretions. Heavy minerals identified by SEM include detrital zircon, thorite, titanite, authigenic fluorite, galena, sphene, and sphalerite and apatite, monazite and epidote-group minerals that appear to be of later stage metamorphic origin, some a product of hydrothermal feldspar alteration. Zircon and monazite show evidence of partial corrosion and/or new overgrowth. Titanite occurs in greater abundance in the SP1/69 section than other boreholes, where it exhibits a porphyroblastic texture suggesting secondary growth. These features all suggest modification of detrital minerals by metamorphic fluids and therefore some possible modification of bulk geochemical composition. Pyrite is abundant, commonly occurring as framboidal and occasional euhedral grains. Pyrite-bearing, calcite veins are common in the Whitehill Formation. Some pyrite is metamorphosed to pyrrhotite in the shales adjacent to dolerite intrusions. The carbonate deposits in the lower Ecca occur mostly as large concretions of 0.5-2.5 m in diameter at intensely faulted areas, and as laterally continuous beds at less intensely faulted areas. They consist of dominant dolomite with calcite (differentiated by thin section staining) and minor associated quartz veins, and appear to have formed in an early diagenetic stage of the black shale. Five different dolomite-rock textures were identified indicating varying crystal growth conditions. Calcite cementation types accompany these dolomite textures. The major types include mosaic, sparry and bladed/prismatic calcite cement. Calcite occurs mainly as cement in pores and grain replacement, as well as crudely radial septerian veins. XRD indicates that the carbonate concretions are made up of more than 90% dolomite, especially within the intensely folded areas. The remaining 10% consist of post-depositional quartz veins and secondary calcite associated with the quartz veins. In one locality (VAAL) the carbonate samples are dominates by bladed/prismatic calcite. The black shales in this study have similar geochemical signature to previously analysed samples from the Karoo Basin and to black shales worldwide. The geochemical signature results from the combined input of detrital sedimentary materials as well as enrichment or depletions acquired from pore water, biological activity and during diagenesis. Positive correlation of K2O, Na2O with Al2O3 suggests control by the detrital contribution. CaO and P2O5, have a negative correlation with Al2O3 suggesting a biogenic source. Elemental ratios suggest that the sediments derive from felsic source rock, most likely Cape Supergroup and underlying crystalline basement. These shales exhibit different degrees of trace-element enrichment relative to global average shale, the approximate order being Pb> V> Zn> Cr> Cu> Co > Ni. Assessment of selected trace elements, V/(V+Ni), V/Cr, Ni/Co and EF Mn ratios describes the paleoenvironment of these sediments to have been partially oxygenated before sulphate reduction interface. The pyrite size distribution, DOP, Fe and S correlation points to an organic matter limited environment, where the main sulphur sink is pyrite rather than organic matter. The DOP and Fe/Al indicated that the sediments became anoxic at the sediment-water interface (early diagenetic stages). V/Cr assessment of the dolomite concretions suggested partially oxygenated environment corresponding to the black shale deposition. The occurrence of concretions at the base of the Whitehill Formation, which has the highest TOC content of 14% compared to other associated formations, is evidence that organic matter preservation was important to their origins. The parameters used here to assess the redox conditions of the black shales and the dolomite concretions in this region of the Karoo Basin suggest a normal marine redox environment, rather than the anoxic Black Sea-type environment. The conditions that affected the lower Ecca formations varied from semi-oxygenated to oxygen depletion environment. The oxygen depletion environment occurred during the deposition of the Whitehill Formation of which organic matter preservation was favoured..
- Full Text:
- Date Issued: 2019
Application of hidden Markov models and their extensions to animal movement data
- Authors: Van Niekerk, Bracken
- Date: 2018
- Subjects: Markov processes Animal locomotion Time-series analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23835 , vital:30624
- Description: Hidden Markov Models (HMMs) have become increasingly popular in animal movement studies as they provide a flexible modelling approach and take the correlation between successive observations into account. They can segment the movement paths into latent states, which can be considered as rough proxies for the behaviours of the animals. This study comprises of two sections, both involving the application of HMMs to large terrestrial mammal movement data. Usually step lengths representing the displacement distances between successive observations, turning angles measuring the tortuosity, or a bivariate input of both variables are used as inputs in the models. It has been found in the literature that the turning angle is either included in the modelling process or it is excluded without much justification for doing so. The first part of this study investigates the nfluence of the turning angle on the model output and resultant interpretations of the HMMs when modelling the trajectories of large terrestrial mammals in southern Africa. Results revealed at different time scales, and for both predator and herbivore species in this study, that the turning angle does not influence the state allocation of the HMMs, which is the main output in terms of interpreting the behaviours of the animals. It is thought in most cases that the inclusion of the turning angle overcomplicates the models unnecessarily without contributing any additional information in terms of the behavioural interpretations or improving the overall fit of the models. This was found for the variety of movements of the species under observation in this study. The second part of this study attempts to validate the state allocation of the HMMs fitted to eland trajectories in the Greater Addo Elephant National Park in the Eastern Cape, with the use of camera trap data. This presented a unique opportunity as this type of data is mainly used for abundance or capture-recapture studies, and the HMMs are rarely validated as the true behaviours of the animals are seldom known. Results revealed that the same diel patterns were detected by the HMMs that were shown by the classified camera trap data. Direct comparisons of the observations where the dates and times matched for the telemetry and camera trap data could be done in several rare instances, which revealed many similarities. Although it was not an ideal comparison, the camera trap data provided a rough validation of the state allocation of the HMMs used in the study.
- Full Text:
- Date Issued: 2018
- Authors: Van Niekerk, Bracken
- Date: 2018
- Subjects: Markov processes Animal locomotion Time-series analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23835 , vital:30624
- Description: Hidden Markov Models (HMMs) have become increasingly popular in animal movement studies as they provide a flexible modelling approach and take the correlation between successive observations into account. They can segment the movement paths into latent states, which can be considered as rough proxies for the behaviours of the animals. This study comprises of two sections, both involving the application of HMMs to large terrestrial mammal movement data. Usually step lengths representing the displacement distances between successive observations, turning angles measuring the tortuosity, or a bivariate input of both variables are used as inputs in the models. It has been found in the literature that the turning angle is either included in the modelling process or it is excluded without much justification for doing so. The first part of this study investigates the nfluence of the turning angle on the model output and resultant interpretations of the HMMs when modelling the trajectories of large terrestrial mammals in southern Africa. Results revealed at different time scales, and for both predator and herbivore species in this study, that the turning angle does not influence the state allocation of the HMMs, which is the main output in terms of interpreting the behaviours of the animals. It is thought in most cases that the inclusion of the turning angle overcomplicates the models unnecessarily without contributing any additional information in terms of the behavioural interpretations or improving the overall fit of the models. This was found for the variety of movements of the species under observation in this study. The second part of this study attempts to validate the state allocation of the HMMs fitted to eland trajectories in the Greater Addo Elephant National Park in the Eastern Cape, with the use of camera trap data. This presented a unique opportunity as this type of data is mainly used for abundance or capture-recapture studies, and the HMMs are rarely validated as the true behaviours of the animals are seldom known. Results revealed that the same diel patterns were detected by the HMMs that were shown by the classified camera trap data. Direct comparisons of the observations where the dates and times matched for the telemetry and camera trap data could be done in several rare instances, which revealed many similarities. Although it was not an ideal comparison, the camera trap data provided a rough validation of the state allocation of the HMMs used in the study.
- Full Text:
- Date Issued: 2018
The effects of vascular targeted bi-functionalized aunps on hepatic lipid metabolism of a diet-induced rats
- Authors: Singo, Dakalo Gladwell
- Date: 2020
- Subjects: Bile acids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47072 , vital:39780
- Description: Introduction: Obesity is a metabolic disease in which the accumulation of excessive fat in the adipose tissue may interfere with the normal maintenance of a healthy state. However, there is only a limited number of drugs approved for the treatment of obesity. For this purpose, target therapies are receiving more attention as a preferred treatment to reduce the burden of chronic diseases which are associated with the current strategies. Nanotechnology is a highly promising field that offers a nanotechnology-based drug delivery system as a novel means of solving issues associated with the toxicity of conventional anti-obesity drugs. Vascular targeted nanotherapy (targeted bi-functionalized nanoparticles) as a strategy that can overcome the current available anti-obesity drugs. Aim: This study sought to understand the effects of nanotherapy in the hepatic lipid metabolism and secretion of bile acids Research focus: The effects of gold nanotherapy on the bile acid biosynthetic enzymes, transporters and lipogenic enzymes of rats that were on a high fat diet. Conclusion: The study shows low expression in the majority of genes responsible for bile acid synthesis and a lipogenic pathway; therefore, the effects of nanotherapy exhibit low toxicity in the hepatic lipid metabolism.
- Full Text:
- Date Issued: 2020
- Authors: Singo, Dakalo Gladwell
- Date: 2020
- Subjects: Bile acids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47072 , vital:39780
- Description: Introduction: Obesity is a metabolic disease in which the accumulation of excessive fat in the adipose tissue may interfere with the normal maintenance of a healthy state. However, there is only a limited number of drugs approved for the treatment of obesity. For this purpose, target therapies are receiving more attention as a preferred treatment to reduce the burden of chronic diseases which are associated with the current strategies. Nanotechnology is a highly promising field that offers a nanotechnology-based drug delivery system as a novel means of solving issues associated with the toxicity of conventional anti-obesity drugs. Vascular targeted nanotherapy (targeted bi-functionalized nanoparticles) as a strategy that can overcome the current available anti-obesity drugs. Aim: This study sought to understand the effects of nanotherapy in the hepatic lipid metabolism and secretion of bile acids Research focus: The effects of gold nanotherapy on the bile acid biosynthetic enzymes, transporters and lipogenic enzymes of rats that were on a high fat diet. Conclusion: The study shows low expression in the majority of genes responsible for bile acid synthesis and a lipogenic pathway; therefore, the effects of nanotherapy exhibit low toxicity in the hepatic lipid metabolism.
- Full Text:
- Date Issued: 2020
Constraints in attainment of sustainable human settlements at Kwamaphumulo Local Municipality
- Authors: Sikhosana, Phindokuhle
- Date: 2020
- Subjects: Human settlements , Sustainable development
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47181 , vital:39829
- Description: This study sought to investigate the constraints in the attainment of sustainable human settlement in KwaMaphumulo Local Municipality at iLembe District in KwaZulu-Natal, South Africa. The aim of this study was to investigate the constraints that limit the achievement of the ideal of sustainable human settlement development in the KwaMaphumulo Local Municipality. Furthermore, the study sought to determine the impact of these constraints on sustainable development and to proffer measures that can be taken to combat stagnant or underdevelopment in the area. A mixed-method approach is followed in this study, which considers a triangulation of quantitative and qualitative data collection, analysis and interpretation techniques. It is important to note that in the past years since South Africa became a democratic country, there have been countless efforts with regard to overcoming the problems created during the apartheid era. These problems stemmed from a distorted spatial, social, economic and political background that was advocated by both segregationist public policies and the planning systems of the Apartheid Regime. In recent years, South African cities have also been faced with environmental issues, which are imperative to the future development of the country. With all these issues in mind, we see that the many efforts that are put in place by government always fall short of solving the problems. This research report looked at the constraints that affect the KwaMaphumulo Local Municipality in attaining sustainable human settlements and whether the efforts of redistribution and equality have been enough to overcome the problems. The key findings of the study were that constraints in attaining sustainable human settlements in the KwaMaphumulo Local Municipality negatively impacts on the development in the area. The level of services being provided is poor. There is an apparent disconnect between traditional leaders and the municipality councillor as development management and vision are concerned. Furthermore, the development programmes and projects do not seem to address the critical needs of the community. Housing development is narrow minded with a focus on the top structure and a failure to include basic services and infrastructure. Houses built that are financed by subsidies are of poor quality. The latter situation results in more able‐ bodied, skilled and capable people emigrating to developed areas.
- Full Text:
- Date Issued: 2020
- Authors: Sikhosana, Phindokuhle
- Date: 2020
- Subjects: Human settlements , Sustainable development
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47181 , vital:39829
- Description: This study sought to investigate the constraints in the attainment of sustainable human settlement in KwaMaphumulo Local Municipality at iLembe District in KwaZulu-Natal, South Africa. The aim of this study was to investigate the constraints that limit the achievement of the ideal of sustainable human settlement development in the KwaMaphumulo Local Municipality. Furthermore, the study sought to determine the impact of these constraints on sustainable development and to proffer measures that can be taken to combat stagnant or underdevelopment in the area. A mixed-method approach is followed in this study, which considers a triangulation of quantitative and qualitative data collection, analysis and interpretation techniques. It is important to note that in the past years since South Africa became a democratic country, there have been countless efforts with regard to overcoming the problems created during the apartheid era. These problems stemmed from a distorted spatial, social, economic and political background that was advocated by both segregationist public policies and the planning systems of the Apartheid Regime. In recent years, South African cities have also been faced with environmental issues, which are imperative to the future development of the country. With all these issues in mind, we see that the many efforts that are put in place by government always fall short of solving the problems. This research report looked at the constraints that affect the KwaMaphumulo Local Municipality in attaining sustainable human settlements and whether the efforts of redistribution and equality have been enough to overcome the problems. The key findings of the study were that constraints in attaining sustainable human settlements in the KwaMaphumulo Local Municipality negatively impacts on the development in the area. The level of services being provided is poor. There is an apparent disconnect between traditional leaders and the municipality councillor as development management and vision are concerned. Furthermore, the development programmes and projects do not seem to address the critical needs of the community. Housing development is narrow minded with a focus on the top structure and a failure to include basic services and infrastructure. Houses built that are financed by subsidies are of poor quality. The latter situation results in more able‐ bodied, skilled and capable people emigrating to developed areas.
- Full Text:
- Date Issued: 2020
Impacts of African elephant feeding on white rhinoceros foraging opportunities
- Authors: Prinsloo, Dominique
- Date: 2017
- Subjects: Herbivores -- Ecology -- South Africa , Grassland ecology -- South Africa Animal-plant relationships -- South Africa Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13768 , vital:27306
- Description: In this study, I investigated the interaction between two megaherbivores, the African elephant and white rhinoceros, that has the potential to impact grazing lawns of which white rhino are the creators and maintainers and elephants are potentially the modifiers. I hypothesized that as elephants browse, they discard a variety of coarse woody debris onto the ground; should this woody debris (of varying amounts and sizes) fall onto grazing lawns, white rhino either move them, consume grass around the woody debris or abandon the lawn entirely. If high levels of woody debris are deposited here, grazing by white rhino is likely to be prevented, at which time I predicted that mesoherbivores would have a competitive advantage in accessing forage that white rhino cannot. I examined the mechanistic links between different levels of elephant-deposited woody debris and grass response at a point scale and feeding patch spatial scale of grazing lawns in an African savanna. In addition, I assessed the response of mesoherbivores in terms of vigilance behaviour with increasing levels of predation risk posed by increasing levels of woody debris. I present the first evidence of an indirect effect of elephant on white rhino foraging behaviour. I demonstrate how increasing levels of woody debris lead to a decreasing probability of foraging by white rhino. I also demonstrate how the probability of foraging by mesoherbivores increases as the amount of forage increases. However, since this study took place during a severe drought where resources are extremely limited, I was unable to properly separate the effects of elephant-deposited woody debris from the severe lack of rainfall on grass response and subsequently herbivore foraging behaviour. Due possibly to the drought, mesoherbivores responded less or not at all to risk factors such as woody debris therefore woody debris was not a predictor of vigilance behaviour in my study. This study contributes to our understanding of how the impacts of elephants, as ecosystem engineers, have cascading effects on savanna ecosystems. My study showed that elephant impact mediates the foraging behaviour of white rhino during a drought. However, under average rainfall periods, my original hypothesized effect of the indirect impacts of elephants on white rhino foraging and grazing lawn dynamics could still hold. This key hypothesis that I was unable to test under ‘normal’ conditions due to the drought is still valid and functionally important for understanding the ecosystem processes driving grazing lawn formation, persistence and composition in African savannas where elephants and white rhinos coexist.
- Full Text:
- Date Issued: 2017
- Authors: Prinsloo, Dominique
- Date: 2017
- Subjects: Herbivores -- Ecology -- South Africa , Grassland ecology -- South Africa Animal-plant relationships -- South Africa Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13768 , vital:27306
- Description: In this study, I investigated the interaction between two megaherbivores, the African elephant and white rhinoceros, that has the potential to impact grazing lawns of which white rhino are the creators and maintainers and elephants are potentially the modifiers. I hypothesized that as elephants browse, they discard a variety of coarse woody debris onto the ground; should this woody debris (of varying amounts and sizes) fall onto grazing lawns, white rhino either move them, consume grass around the woody debris or abandon the lawn entirely. If high levels of woody debris are deposited here, grazing by white rhino is likely to be prevented, at which time I predicted that mesoherbivores would have a competitive advantage in accessing forage that white rhino cannot. I examined the mechanistic links between different levels of elephant-deposited woody debris and grass response at a point scale and feeding patch spatial scale of grazing lawns in an African savanna. In addition, I assessed the response of mesoherbivores in terms of vigilance behaviour with increasing levels of predation risk posed by increasing levels of woody debris. I present the first evidence of an indirect effect of elephant on white rhino foraging behaviour. I demonstrate how increasing levels of woody debris lead to a decreasing probability of foraging by white rhino. I also demonstrate how the probability of foraging by mesoherbivores increases as the amount of forage increases. However, since this study took place during a severe drought where resources are extremely limited, I was unable to properly separate the effects of elephant-deposited woody debris from the severe lack of rainfall on grass response and subsequently herbivore foraging behaviour. Due possibly to the drought, mesoherbivores responded less or not at all to risk factors such as woody debris therefore woody debris was not a predictor of vigilance behaviour in my study. This study contributes to our understanding of how the impacts of elephants, as ecosystem engineers, have cascading effects on savanna ecosystems. My study showed that elephant impact mediates the foraging behaviour of white rhino during a drought. However, under average rainfall periods, my original hypothesized effect of the indirect impacts of elephants on white rhino foraging and grazing lawn dynamics could still hold. This key hypothesis that I was unable to test under ‘normal’ conditions due to the drought is still valid and functionally important for understanding the ecosystem processes driving grazing lawn formation, persistence and composition in African savannas where elephants and white rhinos coexist.
- Full Text:
- Date Issued: 2017
The impact of the construction regulations 2014 on a water utility’s projects’ health and safety performance in South Africa
- Authors: Malindi, Rajandree Mandy
- Date: 2018
- Subjects: Construction industry -- Safety regulations -- South Africa , Construction industry -- Standards -- South Africa Construction industry -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/31655 , vital:31645
- Description: The construction industry plays a major role in South Africa’s economic development. Since promulgation of the Construction Regulations, the expectation is that project stakeholders are placing more emphasis on H&S to contribute to project success. The study aimed to assess the impact of the involvement of clients and other project stakeholders on the overall project H&S performance on projects undertaken by a large water utility. The scope was limited to the organisation’s engineering and operations division and its internal project stakeholders, namely the designers, quantity surveyors, project managers, and construction H&S professionals. Local literature pointed out that poor construction H&S performance is attributable to a lack of management commitment, inadequate supervision, inadequate or lack of H&S training, lack of worker involvement, personal risk appreciation and work pressures (cidb, 2009: 37). International literature indicated that the total CoA exceeds the cost of H&S (cidb, 2009: 9). Quantitative methods were utilised in two phases to gather and analyse data. In Phase 1, a questionnaire was developed and distributed to a target population, and in Phase 2, data was obtained from existing records of historic and completed project files for projects undertaken by the water utility. A total of 67 responses were used to analyse data. All stakeholders somehow contributed to H&S however, most respondents regarded CHS professionals, contractors and PMs as the primary stakeholders. The study found that stakeholders perceived H&S to be influenced during the later rather than the initial stages of projects and that H&S actions were significantly undertaken during stage 5. The frequency of H&S actions varied with each stakeholder dependent on the stage in which they were involved in. Recommendations were for H&S to be integrated in the initial stages of projects and for a follow up research to be conducted to investigate if there are improvements during the six project stages after full implementation of the Construction Regulations 2014. This requirement will force industry to comply and most importantly to drive joint efforts by the various stakeholders.
- Full Text:
- Date Issued: 2018
- Authors: Malindi, Rajandree Mandy
- Date: 2018
- Subjects: Construction industry -- Safety regulations -- South Africa , Construction industry -- Standards -- South Africa Construction industry -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/31655 , vital:31645
- Description: The construction industry plays a major role in South Africa’s economic development. Since promulgation of the Construction Regulations, the expectation is that project stakeholders are placing more emphasis on H&S to contribute to project success. The study aimed to assess the impact of the involvement of clients and other project stakeholders on the overall project H&S performance on projects undertaken by a large water utility. The scope was limited to the organisation’s engineering and operations division and its internal project stakeholders, namely the designers, quantity surveyors, project managers, and construction H&S professionals. Local literature pointed out that poor construction H&S performance is attributable to a lack of management commitment, inadequate supervision, inadequate or lack of H&S training, lack of worker involvement, personal risk appreciation and work pressures (cidb, 2009: 37). International literature indicated that the total CoA exceeds the cost of H&S (cidb, 2009: 9). Quantitative methods were utilised in two phases to gather and analyse data. In Phase 1, a questionnaire was developed and distributed to a target population, and in Phase 2, data was obtained from existing records of historic and completed project files for projects undertaken by the water utility. A total of 67 responses were used to analyse data. All stakeholders somehow contributed to H&S however, most respondents regarded CHS professionals, contractors and PMs as the primary stakeholders. The study found that stakeholders perceived H&S to be influenced during the later rather than the initial stages of projects and that H&S actions were significantly undertaken during stage 5. The frequency of H&S actions varied with each stakeholder dependent on the stage in which they were involved in. Recommendations were for H&S to be integrated in the initial stages of projects and for a follow up research to be conducted to investigate if there are improvements during the six project stages after full implementation of the Construction Regulations 2014. This requirement will force industry to comply and most importantly to drive joint efforts by the various stakeholders.
- Full Text:
- Date Issued: 2018
Predicting reintroduction outcomes: assessing the feasibility of reintroducing African wild dog to a small protected area
- Authors: Vogel, John Thomas
- Date: 2018
- Subjects: African wild dog , Wild dogs -- South Africa Wild dogs -- Conservation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36464 , vital:33947
- Description: Large mammalian carnivores have experienced significant contractions in population sizes and geographical ranges. The conservation of large carnivores is crucially important, particularly due to their vulnerability to extinction and their functional significance and ability to structure ecosystems. Due to an expanding human footprint, large carnivores are increasingly subject to modified and spatially constrained habitats. A growing debate exists as to how to conserve and coexist with large carnivores in an anthropogenically induced environment. Reintroduction, as a conservation tool to restore locally extirpated large carnivores to portions of their former ranges is increasingly being applied. However, in South Africa, habitat to support large carnivores remain small and non-contiguous. Food is a fundamental ecological requirement to sustain reintroduced large carnivores. Therefore, an understanding of large predator foraging patterns can be informative in the context of how the predator species influences and utilises a novel ecosystem. We investigated the foraging behaviour of reintroduced African wild dog (Lycaon pictus) at five small protected areas in KwaZulu-Natal, South Africa. Wild dog utilised 16 prey species, albeit they primarily used nyala (Tragelaphus angasii) and impala (Aepyceros melampus) which collectively form 75 % of their diet. Only nyala was significantly preferred, suggesting that this prey species is used in greater proportion to their abundance. As wild dogs are social cooperative hunters, we tested whether wild dog pack size was correlated to prey mass selection. There was no evidence to suggest that larger packs use larger prey. However, the mean wild dog pack size in our sample sites, was relatively smaller than those encountered elsewhere. Furthermore, wild dog have been shown to modify their hunting behaviour in the presence of wildlife-proof fencing, by using fences to aid in the capture of larger prey species than would innately occur. We compared the prey mass of wild dog kills in relation to proximity of these hard boundaries. Despite the affinity towards kills occurring within 200 m of fences, the upward bias caused by fences on prey mass selection was inconsistent across sample sites. The relatively small size of wild dogs makes them particularly vulnerable to competition. As the energetic output of wild dog is high, interspecific competition can increase foraging costs. The reintroduction of large carnivores to small artificially induced systems may be a contentious issue as resources available to support large carnivores are expected to be relatively more finite. We compared both the potential inter- and intraspecific dietary niche dimensions of an intact large carnivore guild in context of a wild dog reintroduction. We determined cheetah (Acinonyx jubatus), leopard (Panthera pardus), and lion (Panthera leo) prey composition, diet breadth, overlap, prey preference and predicted the density of an intact large carnivore guild in a novel landscape. Further, we compared the foraging behaviour of these large carnivores to that of wild dog. Our findings suggest that large African carnivores in small protected areas are subject to a considerable dietary niche overlap. Wild dog and cheetah, particularly reproductive females with dependent offspring, displayed the greatest potential for dietary overlap and subsequent competition. Leopard and lion at the population species level exhibited greater degrees of foraging plasticity. Lion displayed a contrasting prey species preference to sympatric predators as they selected for prey items frequently avoided by cheetah, leopard and wild dog. The proposed wild dog reintroduction site is expected to sustain seven wild dog based on the availability of preferred prey biomass. However, the reintroduction of wild dog to the small protected area is expected to have negative lateral trophic influences on other species of conservation concern. This should be of vital importance to management of the protected area. As the influence of competition in food-web and population dynamics, particularly in resource poor environments may be profound, our research highlights the need to assess the influence of competitive forces in structuring and restoring large predators to portions of their historical range.
- Full Text:
- Date Issued: 2018
- Authors: Vogel, John Thomas
- Date: 2018
- Subjects: African wild dog , Wild dogs -- South Africa Wild dogs -- Conservation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36464 , vital:33947
- Description: Large mammalian carnivores have experienced significant contractions in population sizes and geographical ranges. The conservation of large carnivores is crucially important, particularly due to their vulnerability to extinction and their functional significance and ability to structure ecosystems. Due to an expanding human footprint, large carnivores are increasingly subject to modified and spatially constrained habitats. A growing debate exists as to how to conserve and coexist with large carnivores in an anthropogenically induced environment. Reintroduction, as a conservation tool to restore locally extirpated large carnivores to portions of their former ranges is increasingly being applied. However, in South Africa, habitat to support large carnivores remain small and non-contiguous. Food is a fundamental ecological requirement to sustain reintroduced large carnivores. Therefore, an understanding of large predator foraging patterns can be informative in the context of how the predator species influences and utilises a novel ecosystem. We investigated the foraging behaviour of reintroduced African wild dog (Lycaon pictus) at five small protected areas in KwaZulu-Natal, South Africa. Wild dog utilised 16 prey species, albeit they primarily used nyala (Tragelaphus angasii) and impala (Aepyceros melampus) which collectively form 75 % of their diet. Only nyala was significantly preferred, suggesting that this prey species is used in greater proportion to their abundance. As wild dogs are social cooperative hunters, we tested whether wild dog pack size was correlated to prey mass selection. There was no evidence to suggest that larger packs use larger prey. However, the mean wild dog pack size in our sample sites, was relatively smaller than those encountered elsewhere. Furthermore, wild dog have been shown to modify their hunting behaviour in the presence of wildlife-proof fencing, by using fences to aid in the capture of larger prey species than would innately occur. We compared the prey mass of wild dog kills in relation to proximity of these hard boundaries. Despite the affinity towards kills occurring within 200 m of fences, the upward bias caused by fences on prey mass selection was inconsistent across sample sites. The relatively small size of wild dogs makes them particularly vulnerable to competition. As the energetic output of wild dog is high, interspecific competition can increase foraging costs. The reintroduction of large carnivores to small artificially induced systems may be a contentious issue as resources available to support large carnivores are expected to be relatively more finite. We compared both the potential inter- and intraspecific dietary niche dimensions of an intact large carnivore guild in context of a wild dog reintroduction. We determined cheetah (Acinonyx jubatus), leopard (Panthera pardus), and lion (Panthera leo) prey composition, diet breadth, overlap, prey preference and predicted the density of an intact large carnivore guild in a novel landscape. Further, we compared the foraging behaviour of these large carnivores to that of wild dog. Our findings suggest that large African carnivores in small protected areas are subject to a considerable dietary niche overlap. Wild dog and cheetah, particularly reproductive females with dependent offspring, displayed the greatest potential for dietary overlap and subsequent competition. Leopard and lion at the population species level exhibited greater degrees of foraging plasticity. Lion displayed a contrasting prey species preference to sympatric predators as they selected for prey items frequently avoided by cheetah, leopard and wild dog. The proposed wild dog reintroduction site is expected to sustain seven wild dog based on the availability of preferred prey biomass. However, the reintroduction of wild dog to the small protected area is expected to have negative lateral trophic influences on other species of conservation concern. This should be of vital importance to management of the protected area. As the influence of competition in food-web and population dynamics, particularly in resource poor environments may be profound, our research highlights the need to assess the influence of competitive forces in structuring and restoring large predators to portions of their historical range.
- Full Text:
- Date Issued: 2018
Construction management’s perceptions of health and safety
- Authors: Sigama, Takalani
- Date: 2018
- Subjects: Construction industry -- Management , Building -- Safety measures Construction industry -- Health aspects Construction industry -- Safety regulations
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35713 , vital:33784
- Description: Projects in the construction sector are reputed for poor health and safety (H&S) performance, compared to other industries. This can be attributed to, inter alia, a relatively uncontrolled working environment, inherent operational risks, workers' behaviour in relation to H&S commitment, cultural and religious beliefs, and uncertainties inherent in projects. Hazards and risk arising from poor H&S practices result in injuries, and in some cases, fatalities. The aim of this study is to explore the perceptions of construction management regarding H&S on construction sites. This study investigates the relationship between behaviours, attitudes, perceptions, and behaviours towards H&S, and compares cultural divergences among levels of construction personnel, namely construction management, construction supervision, construction H&S personnel, and H&S representatives. The construction industry has for many years developed and maintained a very bad reputation for coping with project cost, H&S, quality, and schedule. The industry often delivers projects late, and contributes to a disproportionate rate of work-related injuries, and fatalities. Project H&S management is acknowledged as one of the techniques that could be improved on construction projects to enhance performance of construction contractors in South Africa. To answer the research question: ‘Why construction management perceive H&S as a hindrance to production?” the mixed-method research approach was used. An indepth literature review with respect to project H&S was carried out, followed by qualitative and quantitative empirical research. The study established the need for H&S training and awareness of Construction Managers, Construction Supervisors, Construction Health and Safety Managers (CHSMs), Officers (CHSOs), and H&S Representatives. The study recommends that an H&S training needs analysis is critical for all employees, since it raises H&S awareness among all stakeholders in the construction industry, and enables the development of training plans, thereby supporting the reduction of accidents and related incident.
- Full Text:
- Date Issued: 2018
- Authors: Sigama, Takalani
- Date: 2018
- Subjects: Construction industry -- Management , Building -- Safety measures Construction industry -- Health aspects Construction industry -- Safety regulations
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35713 , vital:33784
- Description: Projects in the construction sector are reputed for poor health and safety (H&S) performance, compared to other industries. This can be attributed to, inter alia, a relatively uncontrolled working environment, inherent operational risks, workers' behaviour in relation to H&S commitment, cultural and religious beliefs, and uncertainties inherent in projects. Hazards and risk arising from poor H&S practices result in injuries, and in some cases, fatalities. The aim of this study is to explore the perceptions of construction management regarding H&S on construction sites. This study investigates the relationship between behaviours, attitudes, perceptions, and behaviours towards H&S, and compares cultural divergences among levels of construction personnel, namely construction management, construction supervision, construction H&S personnel, and H&S representatives. The construction industry has for many years developed and maintained a very bad reputation for coping with project cost, H&S, quality, and schedule. The industry often delivers projects late, and contributes to a disproportionate rate of work-related injuries, and fatalities. Project H&S management is acknowledged as one of the techniques that could be improved on construction projects to enhance performance of construction contractors in South Africa. To answer the research question: ‘Why construction management perceive H&S as a hindrance to production?” the mixed-method research approach was used. An indepth literature review with respect to project H&S was carried out, followed by qualitative and quantitative empirical research. The study established the need for H&S training and awareness of Construction Managers, Construction Supervisors, Construction Health and Safety Managers (CHSMs), Officers (CHSOs), and H&S Representatives. The study recommends that an H&S training needs analysis is critical for all employees, since it raises H&S awareness among all stakeholders in the construction industry, and enables the development of training plans, thereby supporting the reduction of accidents and related incident.
- Full Text:
- Date Issued: 2018
Quality in low - cost houses in Nelson Mandela Bay
- Authors: Gogela, Nwabisa
- Date: 2019
- Subjects: Housing development -- South Africa -- Nelson Mandela Bay Municipality , Housing -- South Africa -- Nelson Mandela Bay Municipality Dwellings -- Defects -- South Africa -- Nelson Mandela Bay Municipality Construction industry -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39709 , vital:35350
- Description: Numerous low cost houses in the Nelson Mandela Bay Municipality, and all over South Africa for that matter, have been handed back to the provincial governments by beneficiaries for remedial work in a government programme called Rectification. Several houses have required demolition and be rebuilt because of patent and latent defects. Government spends huge sums of money in rectifying and fixing the defects on houses that should have been built appropriately from the start; this leads to fruitless and ineffective expenditure. The Department of Human Settlements cannot be solely blamed for the poor quality housing delivery. The contractors, project managers and the inspectors from different stakeholders involved in a project also play a massive role in certifying that the houses delivered are of required norms and standards to assist in minimizing poor quality in the delivery of the low cost housing. The funding spent in rectifying low-cost housing has caused huge backlogs, triggering protests within the communities and, regrettably, incomplete projects around the Nelson Mandela Bay Municipality, contributing to urban decay. The aim of this study was to investigate the poor and unacceptable quality in the delivery of low-cost subsidized houses in the Nelson Mandela Metro Region. The focus of the study was to scrutinize the loopholes and the ambiguities that might exist throughout the life cycle of a low cost housing project, and suggestions to mitigate common problems emerging in various projects. A qualitative research approach was followed in this study. The sample was purposively selected and comprised of 15 beneficiaries residing in the three selected NMBM (housing projects), the Ward Councilors (3), Contractors (3), the Quality Assurance Project Managers managing and foreseeing these projects(3), Quality Coordinators(3) and Inspectors from each organization, (NHBRC, ECDHS and HDA), making three (3) in total.. The study revealed that skills shortage, insufficient workforce training and lack of strict quality control are some of the factors affecting quality. Compliancy to norms and standards is not fully emphasized to the relevant stakeholders during the initiation and the commencement of the project. Tools to measure the effectiveness of quality assurance practices are currently used, but it can be argued that they are not effective enough. The study has offered a set of recommendations to address the key findings.
- Full Text:
- Date Issued: 2019
- Authors: Gogela, Nwabisa
- Date: 2019
- Subjects: Housing development -- South Africa -- Nelson Mandela Bay Municipality , Housing -- South Africa -- Nelson Mandela Bay Municipality Dwellings -- Defects -- South Africa -- Nelson Mandela Bay Municipality Construction industry -- South Africa -- Nelson Mandela Bay Municipality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39709 , vital:35350
- Description: Numerous low cost houses in the Nelson Mandela Bay Municipality, and all over South Africa for that matter, have been handed back to the provincial governments by beneficiaries for remedial work in a government programme called Rectification. Several houses have required demolition and be rebuilt because of patent and latent defects. Government spends huge sums of money in rectifying and fixing the defects on houses that should have been built appropriately from the start; this leads to fruitless and ineffective expenditure. The Department of Human Settlements cannot be solely blamed for the poor quality housing delivery. The contractors, project managers and the inspectors from different stakeholders involved in a project also play a massive role in certifying that the houses delivered are of required norms and standards to assist in minimizing poor quality in the delivery of the low cost housing. The funding spent in rectifying low-cost housing has caused huge backlogs, triggering protests within the communities and, regrettably, incomplete projects around the Nelson Mandela Bay Municipality, contributing to urban decay. The aim of this study was to investigate the poor and unacceptable quality in the delivery of low-cost subsidized houses in the Nelson Mandela Metro Region. The focus of the study was to scrutinize the loopholes and the ambiguities that might exist throughout the life cycle of a low cost housing project, and suggestions to mitigate common problems emerging in various projects. A qualitative research approach was followed in this study. The sample was purposively selected and comprised of 15 beneficiaries residing in the three selected NMBM (housing projects), the Ward Councilors (3), Contractors (3), the Quality Assurance Project Managers managing and foreseeing these projects(3), Quality Coordinators(3) and Inspectors from each organization, (NHBRC, ECDHS and HDA), making three (3) in total.. The study revealed that skills shortage, insufficient workforce training and lack of strict quality control are some of the factors affecting quality. Compliancy to norms and standards is not fully emphasized to the relevant stakeholders during the initiation and the commencement of the project. Tools to measure the effectiveness of quality assurance practices are currently used, but it can be argued that they are not effective enough. The study has offered a set of recommendations to address the key findings.
- Full Text:
- Date Issued: 2019
Procurement challenges faced by Eskom contractors during the tender stage
- Authors: Hlalutye, Thandiwe
- Date: 2018
- Subjects: Management -- Procurement -- South Africa -- Northern Cape , Project management -- South Africa -- Northern Cape Contractors' operation -- South Africa -- Northern Cape -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/30260 , vital:30913
- Description: The procurement process within South Africa has become an increasing focus in open market access for local economic development. The government introduced Preferential Procurement Policy Frame Act 5 of 2000 (PPPFA) which must be followed by all government owned organisations, including parastatals. Eskom, therefore, has to abide to this regulation and, since it started utilising the Act in its tendering process, there has been a challenge to getting contractors who are commercially and technically approved to be able to execute work or projects. The aim of this study is to examine challenges faced by Eskom Northern Cape Operating Unit contractors during the tender stage in terms of tender requirements, whereby they fail to submit all required tender returnables and fail to meet a set threshold in order to be successful and being awarded with the contract. This study undertook an empirical study using a case study of Eskom after a literature review. A questionnaire was used to collect data from all the active contractors on the Eskom Northern Cape Operating Unit data base. The key findings included that; contractors agreed that they still lack understanding of a quality management system. However they disagreed that they are not complying with safety health and environment and that they lack knowledge of technical requirements which leads them to not submitting objective evidence. The study concluded that contracting firms still do not comply with procurement requirements during the tender stage.
- Full Text:
- Date Issued: 2018
- Authors: Hlalutye, Thandiwe
- Date: 2018
- Subjects: Management -- Procurement -- South Africa -- Northern Cape , Project management -- South Africa -- Northern Cape Contractors' operation -- South Africa -- Northern Cape -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/30260 , vital:30913
- Description: The procurement process within South Africa has become an increasing focus in open market access for local economic development. The government introduced Preferential Procurement Policy Frame Act 5 of 2000 (PPPFA) which must be followed by all government owned organisations, including parastatals. Eskom, therefore, has to abide to this regulation and, since it started utilising the Act in its tendering process, there has been a challenge to getting contractors who are commercially and technically approved to be able to execute work or projects. The aim of this study is to examine challenges faced by Eskom Northern Cape Operating Unit contractors during the tender stage in terms of tender requirements, whereby they fail to submit all required tender returnables and fail to meet a set threshold in order to be successful and being awarded with the contract. This study undertook an empirical study using a case study of Eskom after a literature review. A questionnaire was used to collect data from all the active contractors on the Eskom Northern Cape Operating Unit data base. The key findings included that; contractors agreed that they still lack understanding of a quality management system. However they disagreed that they are not complying with safety health and environment and that they lack knowledge of technical requirements which leads them to not submitting objective evidence. The study concluded that contracting firms still do not comply with procurement requirements during the tender stage.
- Full Text:
- Date Issued: 2018
Towards the synthesis of trimethoprim using continuous flow Chemistry
- Authors: Ngwenya, Sandiso
- Date: 2020
- Subjects: Trimethoprim
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47475 , vital:39994
- Description: The continuous flow synthesis of trimethoprim, an antibiotic, was investigated in this study from simple commercially available reagents, such as aniline and dimethylamine. The first step of the synthesis involves a highly exothermic Michael reaction, between acrylonitrile and dimethylamine; process intensification through miniaturization provides a safe and efficient method of synthesis through the use of microreactors. This is afforded by their large surface area-to-volume ratio; one of the many characteristics of continuous flow synthesis that allows for rapid heat dissipation allowing for exothermic reaction to be conducted safely at ambient or higher temperatures. This study was optimized on a Chemtrix Labtrix® Start unit using a Chemtrix reactor achieving a conversion of 99% in 12 sec residence time at 25oC. Subsequently the base catalyzed condensation of the intermediate with 3,4,5- trimethoxybenzaldehyde was investigated using Little Things Factory reactors (Channel diameter: 1.0mm). Maximum conversion (100%) was obtained at 80oC in 20 mins. Due to the poor cyclisation observed with this intermediate, according to literature findings, the 3-dimethylamino group was substituted for aniline. The optimisation for this acid catalysed substitution reaction was performed on a homemade PTFE tubing reactor (Diameter: 0.5mm) and it was found that at 120oC in 10 mins residence time a conversion of 97% was obtained. From the results obtained, an investigation into an integrated process for the condensation and substitution reaction was done using the Little Things Factory system (Channel Diameter: 1.0mm) coupled with a homemade PTFE coil reactor (Diameter: 0.5mm). This process, under optimum conditions of temperature 80oC and residence time of 30 mins, attained a conversion of 76%.
- Full Text:
- Date Issued: 2020
- Authors: Ngwenya, Sandiso
- Date: 2020
- Subjects: Trimethoprim
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47475 , vital:39994
- Description: The continuous flow synthesis of trimethoprim, an antibiotic, was investigated in this study from simple commercially available reagents, such as aniline and dimethylamine. The first step of the synthesis involves a highly exothermic Michael reaction, between acrylonitrile and dimethylamine; process intensification through miniaturization provides a safe and efficient method of synthesis through the use of microreactors. This is afforded by their large surface area-to-volume ratio; one of the many characteristics of continuous flow synthesis that allows for rapid heat dissipation allowing for exothermic reaction to be conducted safely at ambient or higher temperatures. This study was optimized on a Chemtrix Labtrix® Start unit using a Chemtrix reactor achieving a conversion of 99% in 12 sec residence time at 25oC. Subsequently the base catalyzed condensation of the intermediate with 3,4,5- trimethoxybenzaldehyde was investigated using Little Things Factory reactors (Channel diameter: 1.0mm). Maximum conversion (100%) was obtained at 80oC in 20 mins. Due to the poor cyclisation observed with this intermediate, according to literature findings, the 3-dimethylamino group was substituted for aniline. The optimisation for this acid catalysed substitution reaction was performed on a homemade PTFE tubing reactor (Diameter: 0.5mm) and it was found that at 120oC in 10 mins residence time a conversion of 97% was obtained. From the results obtained, an investigation into an integrated process for the condensation and substitution reaction was done using the Little Things Factory system (Channel Diameter: 1.0mm) coupled with a homemade PTFE coil reactor (Diameter: 0.5mm). This process, under optimum conditions of temperature 80oC and residence time of 30 mins, attained a conversion of 76%.
- Full Text:
- Date Issued: 2020
The hypolithic invertebrate community in the eastern Karoo: the role of rock size, microclimate and recolonization
- Authors: Van der Westhuizen, Tara
- Date: 2019
- Subjects: Habitat (Ecology) -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo Invertebrates Ecosystem management -- South Africa -- Karoo Soil microbial ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/44191 , vital:37128
- Description: Hypolithic habitats are important for the persistence of fauna that utilize these habitats as refuges and resource patches. Little is known, however, about the composition and structure of this community in the semi-arid Karoo. The current study therefore aims to explore the patterns and processes behind hypolithic communities, through determining the effect of rock size and baboon presence on the hypolithic community, the influence of rock size on the microclimate experienced under rocks, as well as determining the short- (over five days) and long- (over 12 months) term colonisation of the hypolithic habitat following a rock rolling disturbance, in a semi-arid Karoo environment. The hypolithic fauna encountered, and the temperature and moisture content experienced under a range of rock sizes were measured. Additionally, hypolithic fauna under rocks that were rolled to mimic rock rolling by baboons were sampled after a set period (i.e. over five days and 12 months). Large rocks were found to provide a more stable microclimate than small rocks. The probability of hypolithic fauna presence was influenced by rock size and season, and hypolithic fauna abundance (except in the dry season), richness, body size and biomass did not correlate with rock size. Additionally, the probability of detecting hypolithic fauna under intermediate sized and larger rocks was greater in the presence of baboons than in the absence of baboons, and in the presence of baboons hypolithic fauna richness increased with rock size. Furthermore, it was shown that hypolithic fauna abundance and biomass did not differ under rolled rocks over a short- (i.e. over five days) or long- (i.e. over 12 months) term period. The short-term colonisation of hypolithic habitats was not influenced by season or rock density. Lastly, most of the change in hypolithic community composition (over 12 months) occurred in the first three months and thereafter the hypolithic community composition approached pre-disturbance levels in month 12. The hypolithic habitat was shown to be influenced by a variety of conditions and processes affecting hypolithic community composition and structure. This study therefore contributes to our understanding of the hypolithic invertebrate community in the eastern Karoo, and the influence of rock size, baboon presence, microclimate and colonisation on hypolithic community composition and structure.
- Full Text:
- Date Issued: 2019
- Authors: Van der Westhuizen, Tara
- Date: 2019
- Subjects: Habitat (Ecology) -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo Invertebrates Ecosystem management -- South Africa -- Karoo Soil microbial ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/44191 , vital:37128
- Description: Hypolithic habitats are important for the persistence of fauna that utilize these habitats as refuges and resource patches. Little is known, however, about the composition and structure of this community in the semi-arid Karoo. The current study therefore aims to explore the patterns and processes behind hypolithic communities, through determining the effect of rock size and baboon presence on the hypolithic community, the influence of rock size on the microclimate experienced under rocks, as well as determining the short- (over five days) and long- (over 12 months) term colonisation of the hypolithic habitat following a rock rolling disturbance, in a semi-arid Karoo environment. The hypolithic fauna encountered, and the temperature and moisture content experienced under a range of rock sizes were measured. Additionally, hypolithic fauna under rocks that were rolled to mimic rock rolling by baboons were sampled after a set period (i.e. over five days and 12 months). Large rocks were found to provide a more stable microclimate than small rocks. The probability of hypolithic fauna presence was influenced by rock size and season, and hypolithic fauna abundance (except in the dry season), richness, body size and biomass did not correlate with rock size. Additionally, the probability of detecting hypolithic fauna under intermediate sized and larger rocks was greater in the presence of baboons than in the absence of baboons, and in the presence of baboons hypolithic fauna richness increased with rock size. Furthermore, it was shown that hypolithic fauna abundance and biomass did not differ under rolled rocks over a short- (i.e. over five days) or long- (i.e. over 12 months) term period. The short-term colonisation of hypolithic habitats was not influenced by season or rock density. Lastly, most of the change in hypolithic community composition (over 12 months) occurred in the first three months and thereafter the hypolithic community composition approached pre-disturbance levels in month 12. The hypolithic habitat was shown to be influenced by a variety of conditions and processes affecting hypolithic community composition and structure. This study therefore contributes to our understanding of the hypolithic invertebrate community in the eastern Karoo, and the influence of rock size, baboon presence, microclimate and colonisation on hypolithic community composition and structure.
- Full Text:
- Date Issued: 2019
A Statistical assessment of available solar resource across multiple sites in South Africa
- Authors: Eastwood, Kirstie
- Date: 2019
- Subjects: Mathematical statistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39907 , vital:35505
- Description: Around the globe, fossil fuels remain the primary source of energy at around 78% of the world’s total energy consumption. However, the associated carbon emissions, environmental impact, the depletion of fossil fuels and price and cost volatility are factors influencing the growing popularity of research into renewable energy. Solar power is acknowledged as the fastest-growing renewable energy, but the uncertainty surrounding the long-term projections of solar irradiance available for energy conversion is a hindrance when discussing the financial risk with potential investors. This study investigates the quality of freely available solar resource data in South Africa as well as proposes techniques for potential solar farm site comparisons. Tolerance intervals derived within a Bayesian framework provide information on the future available solar resource across multiple sites. These techniques capture the inherent variability in the available solar resource which equips investors with statistical methods that lead to the better understanding of the solar resource and thus aids in better decision-making.
- Full Text:
- Date Issued: 2019
- Authors: Eastwood, Kirstie
- Date: 2019
- Subjects: Mathematical statistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39907 , vital:35505
- Description: Around the globe, fossil fuels remain the primary source of energy at around 78% of the world’s total energy consumption. However, the associated carbon emissions, environmental impact, the depletion of fossil fuels and price and cost volatility are factors influencing the growing popularity of research into renewable energy. Solar power is acknowledged as the fastest-growing renewable energy, but the uncertainty surrounding the long-term projections of solar irradiance available for energy conversion is a hindrance when discussing the financial risk with potential investors. This study investigates the quality of freely available solar resource data in South Africa as well as proposes techniques for potential solar farm site comparisons. Tolerance intervals derived within a Bayesian framework provide information on the future available solar resource across multiple sites. These techniques capture the inherent variability in the available solar resource which equips investors with statistical methods that lead to the better understanding of the solar resource and thus aids in better decision-making.
- Full Text:
- Date Issued: 2019
The impact of discounting fees by civil engineering consultants
- Authors: Siqiti, Khulile
- Date: 2020
- Subjects: Consulting engineers , Consultants Civil engineering , Project management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47246 , vital:39836
- Description: The study provides insight into the views and perceptions of consulting engineers on the discounting of professional fees. The purpose of the research was to determine the impact of discounting professional fees in the civil engineering profession and ultimately potential ways in which the civil engineering profession could improve business sustainability. The study included a review of literature, which was utilised to develop a questionnaire. A total of 26 practicing consulting engineers, who are members of Consulting Engineers South Africa (CESA), and represented small, medium and large consulting engineering firms, participated in the questionnaire survey. The questionnaire investigates the respondents’ perceptions on the impact of discounting professional fees in the civil engineering profession and the amount of discount offered as well as the reasons for discounting fees. The results show that the practice of discounting professional fees is widespread, affecting small, medium and large consulting firms. The results also indicate that prevailing market conditions in civil engineering profession are the primary reasons why consulting engineers offer discounts on fees. Respondents agreed that projects are awarded to the lowest bidder during tender process. Respondents also agreed that experienced engineers are allocated less time on projects to manage project costs. The findings suggest that discounting of professional fees is a great concern that needs to be addressed in order to attain profession business sustainability. It is suggested that the Engineering Council of South Africa (ECSA) should regulate the fee structures and ensure that all professionals, whether employed in the public or private sector, understand the basic finances on running a professional consultancy to deliver a service.
- Full Text:
- Date Issued: 2020
- Authors: Siqiti, Khulile
- Date: 2020
- Subjects: Consulting engineers , Consultants Civil engineering , Project management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47246 , vital:39836
- Description: The study provides insight into the views and perceptions of consulting engineers on the discounting of professional fees. The purpose of the research was to determine the impact of discounting professional fees in the civil engineering profession and ultimately potential ways in which the civil engineering profession could improve business sustainability. The study included a review of literature, which was utilised to develop a questionnaire. A total of 26 practicing consulting engineers, who are members of Consulting Engineers South Africa (CESA), and represented small, medium and large consulting engineering firms, participated in the questionnaire survey. The questionnaire investigates the respondents’ perceptions on the impact of discounting professional fees in the civil engineering profession and the amount of discount offered as well as the reasons for discounting fees. The results show that the practice of discounting professional fees is widespread, affecting small, medium and large consulting firms. The results also indicate that prevailing market conditions in civil engineering profession are the primary reasons why consulting engineers offer discounts on fees. Respondents agreed that projects are awarded to the lowest bidder during tender process. Respondents also agreed that experienced engineers are allocated less time on projects to manage project costs. The findings suggest that discounting of professional fees is a great concern that needs to be addressed in order to attain profession business sustainability. It is suggested that the Engineering Council of South Africa (ECSA) should regulate the fee structures and ensure that all professionals, whether employed in the public or private sector, understand the basic finances on running a professional consultancy to deliver a service.
- Full Text:
- Date Issued: 2020
Defect Classification in Photovoltaic Modules through Thermal Infrared Imaging using Machine Learning
- Dunderdale, Christopher, Clohessy, C M
- Authors: Dunderdale, Christopher , Clohessy, C M
- Date: 2020
- Subjects: Photovoltaic power generation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48280 , vital:40838
- Description: As the global energy demand continues to soar, solar energy has become an attractive and environmentally conscious method to meet this demand. This study examines the use of machine learning techniques for defect detection and classification in photovoltaic systems using thermal infrared images. A deep learning and feature-based approach is also investigated for the purpose of detecting and classifying defective photovoltaic modules. The VGG-16 and MobileNet deep learning models are shown to provide good performance for the classification of defects. The scale invariant feature transform (SIFT) descriptor, combined with the random forest and support vector machine classifier, is also used to discriminate between defective and non-defective photovoltaic modules in a South African setting. The successful implementation of this approach has significant potential for cost reduction in defect classification over currently available methods.
- Full Text:
- Date Issued: 2020
- Authors: Dunderdale, Christopher , Clohessy, C M
- Date: 2020
- Subjects: Photovoltaic power generation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48280 , vital:40838
- Description: As the global energy demand continues to soar, solar energy has become an attractive and environmentally conscious method to meet this demand. This study examines the use of machine learning techniques for defect detection and classification in photovoltaic systems using thermal infrared images. A deep learning and feature-based approach is also investigated for the purpose of detecting and classifying defective photovoltaic modules. The VGG-16 and MobileNet deep learning models are shown to provide good performance for the classification of defects. The scale invariant feature transform (SIFT) descriptor, combined with the random forest and support vector machine classifier, is also used to discriminate between defective and non-defective photovoltaic modules in a South African setting. The successful implementation of this approach has significant potential for cost reduction in defect classification over currently available methods.
- Full Text:
- Date Issued: 2020
The influence of briefing on Eastern Cape government project outcomes
- Authors: Binqela, Lukhanyo
- Date: 2019
- Subjects: Government projects -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/44562 , vital:38128
- Description: South African Government projects are frequently completed with large cost overruns, extended schedules, quality concerns and an increase in emerging contractors making a significant loss in projects they undertake. The construction phase has been the focus of many studies on the causes of unfavourable project outcomes. However, the crucial stages in the construction process that influence the success of a project are the early ones. This is where major decisions that influence the features and form of a project occur. This study, which adopts a case study approach, aims to establish the influence of the brief development process on the outcome of Government projects in the Eastern Cape. Through the reviewed literature and primary data collection, the study aimed at establishing the influence of the brief that is utilised for a need analysis, to define a detailed scope of works, stakeholder engagement and the time management on Eastern Cape Government project outcomes. The Sarah Baartman district was the selected geographical scope of research. Five projects were selected; these included three schools, one emergency medical service facility and one office facility. The study revealed that Eastern Cape Government projects brief development is based on the client department 2013 Published Norms and Standards for state buildings and a need analysis for other stakeholders is not considered. The study further revealed that there is no stakeholder management in government projects; therefore, there is no stakeholder engagement plan during the brief development. The study further revealed that government time management is suboptimal because stakeholder needs are not realised. The research also found that Eastern Cape Government projects do not achieve stakeholder satisfaction and are delivered late. However, some Government projects are able to meet the desired quality and are within budget. The study thus proposes that the Eastern Cape Government projects need to adopt the dynamic brief development process and implement stakeholder management. The brief development process should be an ongoing process extending throughout the project life cycle responding in an innovative manner to emerging stakeholder requirements.
- Full Text:
- Date Issued: 2019
- Authors: Binqela, Lukhanyo
- Date: 2019
- Subjects: Government projects -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/44562 , vital:38128
- Description: South African Government projects are frequently completed with large cost overruns, extended schedules, quality concerns and an increase in emerging contractors making a significant loss in projects they undertake. The construction phase has been the focus of many studies on the causes of unfavourable project outcomes. However, the crucial stages in the construction process that influence the success of a project are the early ones. This is where major decisions that influence the features and form of a project occur. This study, which adopts a case study approach, aims to establish the influence of the brief development process on the outcome of Government projects in the Eastern Cape. Through the reviewed literature and primary data collection, the study aimed at establishing the influence of the brief that is utilised for a need analysis, to define a detailed scope of works, stakeholder engagement and the time management on Eastern Cape Government project outcomes. The Sarah Baartman district was the selected geographical scope of research. Five projects were selected; these included three schools, one emergency medical service facility and one office facility. The study revealed that Eastern Cape Government projects brief development is based on the client department 2013 Published Norms and Standards for state buildings and a need analysis for other stakeholders is not considered. The study further revealed that there is no stakeholder management in government projects; therefore, there is no stakeholder engagement plan during the brief development. The study further revealed that government time management is suboptimal because stakeholder needs are not realised. The research also found that Eastern Cape Government projects do not achieve stakeholder satisfaction and are delivered late. However, some Government projects are able to meet the desired quality and are within budget. The study thus proposes that the Eastern Cape Government projects need to adopt the dynamic brief development process and implement stakeholder management. The brief development process should be an ongoing process extending throughout the project life cycle responding in an innovative manner to emerging stakeholder requirements.
- Full Text:
- Date Issued: 2019
Assessment of indigenous forest degradation and deforestation along the wild coast, near Port St John’s, Eastern Cape Province, South Africa
- Katende, Lukyamuzi Lucky Fulgentius
- Authors: Katende, Lukyamuzi Lucky Fulgentius
- Date: 2018
- Subjects: Deforestation -- South Africa -- Eastern Cape , Forest degradation -- South Africa -- Eastern Cape Forest management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/30649 , vital:31006
- Description: Indigenous forests along the Wild Coast of the Eastern Cape Province have experienced both degradation and deforestation over the past decades. In early 2000, steps were taken to rehabilitate some of the degraded areas. Nevertheless, there is no monitoring mechanism in place, so little is known about the extent of degradation and impact of the rehabilitation efforts. The present study assesses the extent to which deforestation and degradation of the indigenous forests have occurred, and evaluates rehabilitation efforts in the study area around Port Saint John’s. Forest degradation was defined as the decrease in forest cover density while deforestation was defined as an increase in the trend of light forests and/ or a decrease in dense forests. The details for this study were obtained from multi – temporal remotely sensed data for a period between 1982 and 2013 (31 years). Multi-temporal Landsat satellite imagery for 1982, 1986, 1989, 2002, 2009 and 2013 was acquired and analysed. On the basis of prior knowledge of the area, the supervised classification approach was used. The Maximum likelihood supervised classification technique was used to extract information from satellite data. The classified images were filtered using a majority filtering procedure to reduce noise. Google Earth (Astrium) ancillary images were used to refine the classification based on expert rules. The derived changes in the degraded and rehabilitated areas were further validated through field visits. The overall image classification accuracy generated from Landsat image data ranged from 80% to 90%. It was noted that the area of dense forest almost doubled between 1986 and 1989, coinciding with a 59% decrease in the light forest. Subsequently, dense forests increased by 14,820 ha while light forests decreased by 16,690 ha between 1989 and 2002. The subsequent reduction in light forest coverage is explained by the establishment of the Participatory Forest Management (PFMA) approach by Department of Water Affairs and Forestry (DWAF) which reversed the degradation trend. However, specific degradation hotspots were identified, particularly where new settlements have been established. The emergence of the non-vegetated area increased gradually from 7% in 1986 to 23.4% in 2013. Notably, dense forest was observed to have experienced higher rates of forest degradation and deforestation than the light forest. The highest number patches were 4 recorded between 2002 and 1998, followed by between 2010 and 2013 and lastly 1986. Based on spatial connectedness of patches, the year 1986 had the highest landscape connectedness of forest vegetation (CONAT = 35.3) followed by 2002 and 1996 while the year 2010 and 2013 had the lowest landscape contiguity. Over the study period, the distribution of patches clearly shows that forest degradation and deforestation rates were lower in the years 1986, 1998 and tremendously increased in the later period of between 2010 and 2013. However, as a result of rehabilitation efforts, dense forest was seen to steadily gain more land than light forest. Finer details of degradation trends could not be easily picked from the images used in the study, given their spatial resolution limitations. That notwithstanding, the trends identified are good for overview decisions. The study has also established that de-agraianisation, forest restoration and rehabilitation greatly contributed to increased forest cover. Therefore, with more use of GIS by forest managers, and imagery of the high resolution being readily available, forests will in future be easily monitored using remote sensing.
- Full Text:
- Date Issued: 2018
- Authors: Katende, Lukyamuzi Lucky Fulgentius
- Date: 2018
- Subjects: Deforestation -- South Africa -- Eastern Cape , Forest degradation -- South Africa -- Eastern Cape Forest management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/30649 , vital:31006
- Description: Indigenous forests along the Wild Coast of the Eastern Cape Province have experienced both degradation and deforestation over the past decades. In early 2000, steps were taken to rehabilitate some of the degraded areas. Nevertheless, there is no monitoring mechanism in place, so little is known about the extent of degradation and impact of the rehabilitation efforts. The present study assesses the extent to which deforestation and degradation of the indigenous forests have occurred, and evaluates rehabilitation efforts in the study area around Port Saint John’s. Forest degradation was defined as the decrease in forest cover density while deforestation was defined as an increase in the trend of light forests and/ or a decrease in dense forests. The details for this study were obtained from multi – temporal remotely sensed data for a period between 1982 and 2013 (31 years). Multi-temporal Landsat satellite imagery for 1982, 1986, 1989, 2002, 2009 and 2013 was acquired and analysed. On the basis of prior knowledge of the area, the supervised classification approach was used. The Maximum likelihood supervised classification technique was used to extract information from satellite data. The classified images were filtered using a majority filtering procedure to reduce noise. Google Earth (Astrium) ancillary images were used to refine the classification based on expert rules. The derived changes in the degraded and rehabilitated areas were further validated through field visits. The overall image classification accuracy generated from Landsat image data ranged from 80% to 90%. It was noted that the area of dense forest almost doubled between 1986 and 1989, coinciding with a 59% decrease in the light forest. Subsequently, dense forests increased by 14,820 ha while light forests decreased by 16,690 ha between 1989 and 2002. The subsequent reduction in light forest coverage is explained by the establishment of the Participatory Forest Management (PFMA) approach by Department of Water Affairs and Forestry (DWAF) which reversed the degradation trend. However, specific degradation hotspots were identified, particularly where new settlements have been established. The emergence of the non-vegetated area increased gradually from 7% in 1986 to 23.4% in 2013. Notably, dense forest was observed to have experienced higher rates of forest degradation and deforestation than the light forest. The highest number patches were 4 recorded between 2002 and 1998, followed by between 2010 and 2013 and lastly 1986. Based on spatial connectedness of patches, the year 1986 had the highest landscape connectedness of forest vegetation (CONAT = 35.3) followed by 2002 and 1996 while the year 2010 and 2013 had the lowest landscape contiguity. Over the study period, the distribution of patches clearly shows that forest degradation and deforestation rates were lower in the years 1986, 1998 and tremendously increased in the later period of between 2010 and 2013. However, as a result of rehabilitation efforts, dense forest was seen to steadily gain more land than light forest. Finer details of degradation trends could not be easily picked from the images used in the study, given their spatial resolution limitations. That notwithstanding, the trends identified are good for overview decisions. The study has also established that de-agraianisation, forest restoration and rehabilitation greatly contributed to increased forest cover. Therefore, with more use of GIS by forest managers, and imagery of the high resolution being readily available, forests will in future be easily monitored using remote sensing.
- Full Text:
- Date Issued: 2018
Assessing growth response patterns of microalgae to varying environmental conditions using sediments from ephemeral wetlands
- Authors: Mazwane, Sixolile
- Date: 2018
- Subjects: Microalgae -- South Africa , Wetland conservation -- South Africa Landscape ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22398 , vital:29966
- Description: Ephemeral wetlands serve as habitats for different fauna and flora. Microalgae make up a bulk of primary production in newly inundated wetlands and have a big influence on the aquatic community structure. As ephemeral wetlands have cyclical drying and wetting phases, algal species found in these habitats have evolved adaptations (i.e. dormancy and cysts) to survive during dry periods and become productive upon inundation. Algae have been used as ecological indicators in many aquatic ecosystems including wetlands, particularly associated with water quality and with varying inundation states. Whilst temperature and water level have been shown to affect microalgal biomass independently, this study aims to assess the effects of these two factors simultaneously on microalgal biomass, species diversity and community changes. The aim of the study was to investigate microalgal dynamics using two ephemeral wetlands in the Nelson Mandela Bay Municipality. The growth response patterns of microalgal communities to varying temperatures and inundation levels through experiments using dry temporary wetland sediments was also assessed. Dry sediments were collected from two depression wetlands with different sediment characteristics (1592 and Elephant Wallow (EW)). The study consisted of replicated treatments with three different surface area: volume ratios (SA:V) (Low surface area: volume (LSAV), Medium (MSAV) and High (HSAV)), inundated with distilled water. The microcosms were placed inside a Conviron environmental growth chamber and illuminated at between 106 to 138 μmol.m-2s-1, with a 12:12 light-dark cycle at constant temperatures of 12 °C (mean winter) and 22 °C (mean summer). Physicochemical data were recorded, and biological samples were collected every 4 days over a 28-day inundation period. In the field, Electrical conductivity (EC) and pH showed a gradual increase over the inundation period. The systems were well oxygenated (6-10 mg L-1). Overall, phytoplankton biomass in the field was ~10 μg L-1 whereas benthic biomass (MPB) was significantly higher 10 – 300 mg L-1. Within the experiments, the phytoplankton biomass showed a pattern while MPB biomass increased gradually for both experiments. There were no significant (p>0.05) differences between the 1592 and EW phytoplankton biomass. However, the MPB biomass showed significant (p<0.05) differences between the two sediments (EW high, 1592 low) and the experiments, respectively. In the winter experiment, the 1592 sediment had high phytoplankton biomass compared to EW, the reverse was observed for the MPB biomass. In summer experiment, similar results were observed in terms of phytoplankton biomass. For the MPBs, 1592 had greater biomass for all treatments compared to EW. The phytoplankton community for both field samples and experiments was dominated by chlorophytes (>50 %), followed by cyanophytes and euglenophytes (with cryptophytes in summer experiment) for both field and experiments. The MPB community was dominated by bacillariophytes (55 %) and chlorophytes (25 %) in the 1592 sediments and this was also the case with EW sediments bacillariophytes (70 %), although cyanophytes (15 %) made up the remainder of the MPB community. The 1592 sediments supported higher diatom abundances under the HSAV compared to the same treatment from the EW wetland suggesting that possibly grain size or texture might be responsible. In contrast, sediments from EW under LSAV conditions showed higher diatom cell numbers possibly indicating that increased water depth has the propensity to support greater diatom assemblages compared with the same water level for sediments from 1592. The results indicate that microalgae community is influenced by sediment type more than it is by water level. From this study it was also established that microalgae were able to reemerge from their dormancy state upon inundation and that tank experiments were successful in simulating natural ephemeral wetland conditions. The findings from this study will add to the available baseline data on microalgal dynamics in the ephemeral wetlands in South Africa, especially in semi-arid areas. This information can be valuable in enhancing our understanding regarding the role of microalgae in ephemeral wetlands in order to conserve them.
- Full Text:
- Date Issued: 2018
- Authors: Mazwane, Sixolile
- Date: 2018
- Subjects: Microalgae -- South Africa , Wetland conservation -- South Africa Landscape ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22398 , vital:29966
- Description: Ephemeral wetlands serve as habitats for different fauna and flora. Microalgae make up a bulk of primary production in newly inundated wetlands and have a big influence on the aquatic community structure. As ephemeral wetlands have cyclical drying and wetting phases, algal species found in these habitats have evolved adaptations (i.e. dormancy and cysts) to survive during dry periods and become productive upon inundation. Algae have been used as ecological indicators in many aquatic ecosystems including wetlands, particularly associated with water quality and with varying inundation states. Whilst temperature and water level have been shown to affect microalgal biomass independently, this study aims to assess the effects of these two factors simultaneously on microalgal biomass, species diversity and community changes. The aim of the study was to investigate microalgal dynamics using two ephemeral wetlands in the Nelson Mandela Bay Municipality. The growth response patterns of microalgal communities to varying temperatures and inundation levels through experiments using dry temporary wetland sediments was also assessed. Dry sediments were collected from two depression wetlands with different sediment characteristics (1592 and Elephant Wallow (EW)). The study consisted of replicated treatments with three different surface area: volume ratios (SA:V) (Low surface area: volume (LSAV), Medium (MSAV) and High (HSAV)), inundated with distilled water. The microcosms were placed inside a Conviron environmental growth chamber and illuminated at between 106 to 138 μmol.m-2s-1, with a 12:12 light-dark cycle at constant temperatures of 12 °C (mean winter) and 22 °C (mean summer). Physicochemical data were recorded, and biological samples were collected every 4 days over a 28-day inundation period. In the field, Electrical conductivity (EC) and pH showed a gradual increase over the inundation period. The systems were well oxygenated (6-10 mg L-1). Overall, phytoplankton biomass in the field was ~10 μg L-1 whereas benthic biomass (MPB) was significantly higher 10 – 300 mg L-1. Within the experiments, the phytoplankton biomass showed a pattern while MPB biomass increased gradually for both experiments. There were no significant (p>0.05) differences between the 1592 and EW phytoplankton biomass. However, the MPB biomass showed significant (p<0.05) differences between the two sediments (EW high, 1592 low) and the experiments, respectively. In the winter experiment, the 1592 sediment had high phytoplankton biomass compared to EW, the reverse was observed for the MPB biomass. In summer experiment, similar results were observed in terms of phytoplankton biomass. For the MPBs, 1592 had greater biomass for all treatments compared to EW. The phytoplankton community for both field samples and experiments was dominated by chlorophytes (>50 %), followed by cyanophytes and euglenophytes (with cryptophytes in summer experiment) for both field and experiments. The MPB community was dominated by bacillariophytes (55 %) and chlorophytes (25 %) in the 1592 sediments and this was also the case with EW sediments bacillariophytes (70 %), although cyanophytes (15 %) made up the remainder of the MPB community. The 1592 sediments supported higher diatom abundances under the HSAV compared to the same treatment from the EW wetland suggesting that possibly grain size or texture might be responsible. In contrast, sediments from EW under LSAV conditions showed higher diatom cell numbers possibly indicating that increased water depth has the propensity to support greater diatom assemblages compared with the same water level for sediments from 1592. The results indicate that microalgae community is influenced by sediment type more than it is by water level. From this study it was also established that microalgae were able to reemerge from their dormancy state upon inundation and that tank experiments were successful in simulating natural ephemeral wetland conditions. The findings from this study will add to the available baseline data on microalgal dynamics in the ephemeral wetlands in South Africa, especially in semi-arid areas. This information can be valuable in enhancing our understanding regarding the role of microalgae in ephemeral wetlands in order to conserve them.
- Full Text:
- Date Issued: 2018
Incidence of bacterial infections and colonisation in patients admitted to a tuberculosis hospital
- Authors: Annear, Dale John
- Date: 2018
- Subjects: Medical microbiology , Microbiology Bacteriology Tuberculosis -- Hospitals -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21482 , vital:29526
- Description: Patients with drug resistant tuberculosis (TB) are treated with multiple antibiotics including moxifloxacin, linezolid, and meropenem, which puts them at greater risk for colonisation by multi-drug resistant (MDR) bacteria. The objectives of this study were to: (i) assess the antimicrobial prescribing patterns practiced within the hospital by retrospective patient file review; (ii) determine the spectrum of bacterial colonisation in TB patients upon admission and during hospitalisation; (iii) identify bacterial isolates and evaluate antimicrobial susceptibility profiles; (iv) detect antimicrobial resistance genes in the bacterial isolates by PCR and DNA sequencing; and (v) investigate genetic relatedness of Klebsiella pneumoniae isolates using Multi Locus Sequence Typing. Nasal, groin and rectal swabs [for the detection of extended spectrum beta lactamases (EBSLs), carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)] were analysed from a cohort of patients (n=37) admitted either from the community (n = 28) or from other healthcare facilities (n=9) to a TB hospital. Swab samples were collected at admission and at four week intervals thereafter during hospitalization. Identification and antimicrobial susceptibility testing of bacterial isolates (n=62) were determined at the National Health Laboratory Services (NHLS) by the VITEK-MS and Vitek 2 systems respectively. Additional antimicrobial susceptibility testing was conducted by Sensititre Gram Negative Xtra (GNFX2) MIC plates. PCR and DNA sequencing were used for detection of resistance genes. Patients (n=13/37; 35%) were colonized by MDR bacteria (ESBLs [n=11], MRSA [n=2]) on admission. Colonization rates were lower in patients admitted from the community (9/28; 32%) compared to those transferred from other healthcare facilities (4/9; 44%). All admitted patients who did not exhibit colonization at baseline and who were resident within the hospital for longer than 4 weeks (17/37; 46% of total patients) became colonised by an ESBL-producing Enterobacteriaceae species. No patients acquired MRSA during hospitalisation. Among ESBL Enterobacteriaceae, Escherichia coli (41/62; 66%) and K. pneumoniae [14/62; 23%]) predominated. Nineteen percent (7/37) of patients demised during their hospitalization. Both the Vitek system and Sensititre Gram Negative Xtra (GNFX2) MIC plates susceptibilities were similar for most antimicrobials, however there were discrepancies for tigecycline susceptibility profiles. A high number of isolates exhibited resistance to aminoglycosides and fluoroquinolones. Genes encoding for ESBLs (CTX-M-14, CTX-M-15, SHV-28, OXA-1, and OXY-2-9) were detected among ESBL Enterobacteriaceae. Two Enterobacteriaceae isolates with reduced carbapenem susceptibility did not contain carbapenemase-encoding genes. MLST revealed unique sequence types and genetic diversity among the K. pneumoniae isolates from hospitalised patients. However, the source and colonization routes of these isolates could not be determined, which requires further investigation. This study provides insight into the spectrum of bacterial pathogen colonisation in hospitalised TB patients and suggests a review of infection control programs and practices at the TB hospital.
- Full Text:
- Date Issued: 2018
- Authors: Annear, Dale John
- Date: 2018
- Subjects: Medical microbiology , Microbiology Bacteriology Tuberculosis -- Hospitals -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21482 , vital:29526
- Description: Patients with drug resistant tuberculosis (TB) are treated with multiple antibiotics including moxifloxacin, linezolid, and meropenem, which puts them at greater risk for colonisation by multi-drug resistant (MDR) bacteria. The objectives of this study were to: (i) assess the antimicrobial prescribing patterns practiced within the hospital by retrospective patient file review; (ii) determine the spectrum of bacterial colonisation in TB patients upon admission and during hospitalisation; (iii) identify bacterial isolates and evaluate antimicrobial susceptibility profiles; (iv) detect antimicrobial resistance genes in the bacterial isolates by PCR and DNA sequencing; and (v) investigate genetic relatedness of Klebsiella pneumoniae isolates using Multi Locus Sequence Typing. Nasal, groin and rectal swabs [for the detection of extended spectrum beta lactamases (EBSLs), carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)] were analysed from a cohort of patients (n=37) admitted either from the community (n = 28) or from other healthcare facilities (n=9) to a TB hospital. Swab samples were collected at admission and at four week intervals thereafter during hospitalization. Identification and antimicrobial susceptibility testing of bacterial isolates (n=62) were determined at the National Health Laboratory Services (NHLS) by the VITEK-MS and Vitek 2 systems respectively. Additional antimicrobial susceptibility testing was conducted by Sensititre Gram Negative Xtra (GNFX2) MIC plates. PCR and DNA sequencing were used for detection of resistance genes. Patients (n=13/37; 35%) were colonized by MDR bacteria (ESBLs [n=11], MRSA [n=2]) on admission. Colonization rates were lower in patients admitted from the community (9/28; 32%) compared to those transferred from other healthcare facilities (4/9; 44%). All admitted patients who did not exhibit colonization at baseline and who were resident within the hospital for longer than 4 weeks (17/37; 46% of total patients) became colonised by an ESBL-producing Enterobacteriaceae species. No patients acquired MRSA during hospitalisation. Among ESBL Enterobacteriaceae, Escherichia coli (41/62; 66%) and K. pneumoniae [14/62; 23%]) predominated. Nineteen percent (7/37) of patients demised during their hospitalization. Both the Vitek system and Sensititre Gram Negative Xtra (GNFX2) MIC plates susceptibilities were similar for most antimicrobials, however there were discrepancies for tigecycline susceptibility profiles. A high number of isolates exhibited resistance to aminoglycosides and fluoroquinolones. Genes encoding for ESBLs (CTX-M-14, CTX-M-15, SHV-28, OXA-1, and OXY-2-9) were detected among ESBL Enterobacteriaceae. Two Enterobacteriaceae isolates with reduced carbapenem susceptibility did not contain carbapenemase-encoding genes. MLST revealed unique sequence types and genetic diversity among the K. pneumoniae isolates from hospitalised patients. However, the source and colonization routes of these isolates could not be determined, which requires further investigation. This study provides insight into the spectrum of bacterial pathogen colonisation in hospitalised TB patients and suggests a review of infection control programs and practices at the TB hospital.
- Full Text:
- Date Issued: 2018
Passive acoustic monitoring of coastal dolphins (Sousa plumbea and Tursiops aduncus) in Plettenberg Bay: temporal patterns and group dynamics
- Authors: Hlati, Kuhle
- Date: 2018
- Subjects: Marine mammals -- Effect of noise on -- Research , Oceanography Aquatic ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/30050 , vital:30813
- Description: In this study, passive acoustic monitoring (PAM) was used to investigate the diel patterns of occurrence and activities of coastal dolphins (Sousa plumbea and Tursiops aduncus) in Plettenberg Bay, during April 2015 - July 2017. Automatic detectors were used to extract dolphin whistles and echolocation clicks from the acoustic recordings. The vocalizations were extracted without identifying the dolphin species due to insufficient visual observation data collected concurrent with the acoustic recordings to conclusively discriminate the two species. The correct detection performance and false alarm rate of the detectors for each acoustic recorder were evaluated and automatic detection protocols were developed. For a recorder that was initially deployed in the study (DSG recorder), the detectors achieved 64 - 80% true detection rates with false alarm rates of 10 - 22%. A more modern recorder (MicroMARS recorder) which replaced this one had a lower signal-to-noise ratio (SNR) and could sample at a higher frequency, the detectors achieved greater than 80% true detection rates and less than 5% false alarm rates. It was evident that SNR and sampling rate influenced the detection performance of the detectors. When acoustic recordings were compared to visual observations which were conducted concurrently with some of the recordings, it was apparent that acoustic recorders performed nearly twice as well as land-based observers in terms of overall detection of dolphin groups. Group size and behaviour affected acoustic detection rates of dolphins; large groups that were visually detected and which were foraging at the time, were more likely to be acoustically detected than small groups or single animals or groups associated travelling at the time. The detection rates of echolocation clicks and whistles showed a diel pattern of occurrence of coastal dolphins in Plettenberg Bay with a higher nighttime than daytime occurrence. The detection rates were higher from midday to midnight with a peak during dusk. The high activity of dolphins in the late afternoon and evening reported in this study was also supported by visual data (afternoons) in the area and acoustic studies in other regions. Comparison of acoustic detection rates and visual data from this study with past observations suggest that the occurrence patterns of T. aduncus in the bay appear to have changed; such a change may be influenced by changes in prey behaviour or distribution, or other factors. The significally higher detection rates of echolocation clicks than whistles and dominant foraging behaviour based on visual data suggest that Robberg may be an important feeding ground for the coastal dolphins that are frequenting Plettenberg Bay. The current study builds on a growing body of literature demonstrating that PAM and automatic detectors are powerful and effective tools for monitoring cetacean species. However, there are several factors that limit the detection of vocalization such as direction of the sound source, distance from hydrophone, sound propagation conditions, low SNR and acoustic masking. Regardless of these limitations, results from PAM showed diel patterns of occurrence of the coastal dolphins in the bay which could have not been achieved from visual monitoring, in particular the high nighttime occurrence patterns. PAM holds potential to be largely utilized in South Africa for dolphin and other cetacean studies. Further research and monitoring using PAM could potentially assist to better understand the drivers of the dolphin occurrence and activity patterns in the bay.
- Full Text:
- Date Issued: 2018
- Authors: Hlati, Kuhle
- Date: 2018
- Subjects: Marine mammals -- Effect of noise on -- Research , Oceanography Aquatic ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/30050 , vital:30813
- Description: In this study, passive acoustic monitoring (PAM) was used to investigate the diel patterns of occurrence and activities of coastal dolphins (Sousa plumbea and Tursiops aduncus) in Plettenberg Bay, during April 2015 - July 2017. Automatic detectors were used to extract dolphin whistles and echolocation clicks from the acoustic recordings. The vocalizations were extracted without identifying the dolphin species due to insufficient visual observation data collected concurrent with the acoustic recordings to conclusively discriminate the two species. The correct detection performance and false alarm rate of the detectors for each acoustic recorder were evaluated and automatic detection protocols were developed. For a recorder that was initially deployed in the study (DSG recorder), the detectors achieved 64 - 80% true detection rates with false alarm rates of 10 - 22%. A more modern recorder (MicroMARS recorder) which replaced this one had a lower signal-to-noise ratio (SNR) and could sample at a higher frequency, the detectors achieved greater than 80% true detection rates and less than 5% false alarm rates. It was evident that SNR and sampling rate influenced the detection performance of the detectors. When acoustic recordings were compared to visual observations which were conducted concurrently with some of the recordings, it was apparent that acoustic recorders performed nearly twice as well as land-based observers in terms of overall detection of dolphin groups. Group size and behaviour affected acoustic detection rates of dolphins; large groups that were visually detected and which were foraging at the time, were more likely to be acoustically detected than small groups or single animals or groups associated travelling at the time. The detection rates of echolocation clicks and whistles showed a diel pattern of occurrence of coastal dolphins in Plettenberg Bay with a higher nighttime than daytime occurrence. The detection rates were higher from midday to midnight with a peak during dusk. The high activity of dolphins in the late afternoon and evening reported in this study was also supported by visual data (afternoons) in the area and acoustic studies in other regions. Comparison of acoustic detection rates and visual data from this study with past observations suggest that the occurrence patterns of T. aduncus in the bay appear to have changed; such a change may be influenced by changes in prey behaviour or distribution, or other factors. The significally higher detection rates of echolocation clicks than whistles and dominant foraging behaviour based on visual data suggest that Robberg may be an important feeding ground for the coastal dolphins that are frequenting Plettenberg Bay. The current study builds on a growing body of literature demonstrating that PAM and automatic detectors are powerful and effective tools for monitoring cetacean species. However, there are several factors that limit the detection of vocalization such as direction of the sound source, distance from hydrophone, sound propagation conditions, low SNR and acoustic masking. Regardless of these limitations, results from PAM showed diel patterns of occurrence of the coastal dolphins in the bay which could have not been achieved from visual monitoring, in particular the high nighttime occurrence patterns. PAM holds potential to be largely utilized in South Africa for dolphin and other cetacean studies. Further research and monitoring using PAM could potentially assist to better understand the drivers of the dolphin occurrence and activity patterns in the bay.
- Full Text:
- Date Issued: 2018