Assessing the impacts of Lantana camara and opportunities for ecological restoration after its removal: does clearing facilitate both soil and native vegetation recovery?
- Authors: Bolosha, Uviwe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466524 , vital:76738 , DOI https://doi.org/10.21504/10962/466524
- Description: Invasive alien plants (IAPs) are one of the major contributing factors to biodiversity loss, and Lantana camara is among the top ten alien invaders worldwide. Lantana camara threatens native biodiversity and human health, prevents natural succession, and has an economic and environmental impact globally. With current climate change and future predictions, these IAPs are anticipated to continue posing huge threats to ecosystem composition, structure, and function. Even though L. camara is a widespread IAP, there is still limited knowledge in South Africa on how it influences soil physicochemical properties at the species level, vegetation communities, and soil seed banks at the community level following its invasion. There is also minimal knowledge on the management and control (i.e., clearing for restoration purposes) of L. camara in South Africa, especially in the Eastern Cape province of South Africa. To address the knowledge gap, this thesis was structured into three main aspects: understanding L. camara invasion mechanisms, evaluating invasion impacts on both the aboveground and belowground communities, and invasion management. The main objectives of this thesis were (i) to examine how L. camara invasion (at a species level) affected soil physicochemical properties across different seasons, (ii) to assess how L. camara influences natural vegetation (at a community level), (iii) to examine the effects of L. camara invasion (at the community level) on belowground soil seed banks and also assess the availability of pioneer native species and IAPs in the soil seed banks, and (iv) to evaluate soil and vegetation responses following L. camara clearing in comparison to invaded and uninvaded conditions. To answer these objectives, different studies were carried out in the Eastern Cape province, South Africa, on various farms within the Albany Thicket Biome. The results (Chapter 3) show that L. camara alters and modifies some soil physical properties, such as soil infiltration rate, repellency, and soil penetration resistance, in the communities it invades. A significant decrease in soil penetration under the L. camara canopy was observed compared to soils from the edge and out position. Moreover, significantly faster infiltration rates were observed in the canopy and edge positions than in the out position. The study also observed that these modifications in soil physical properties vary depending on the season. A seasonal comparison in soil penetration showed that soil was more compact in the dry season than the wet season, and significantly faster infiltration rates were observed in summer than in the other seasons. The soil collected under the invaded sampling positions was mostly wettable (80–100%), and not strongly, severely, or extremely repellent across all the seasons. The changes in soil properties caused by L. camara could create favourable conditions for its growth and invasion. Seasonal changes in soil properties also highlight how environmental conditions, especially temperature and rainfall patterns, can affect soil physical properties. The findings in Chapter 4 observed both the negative and positive impacts of L. camara, where the species did not have negative effects on species richness, diversity, or cover of some native species growth forms (i.e., graminoids and forbs). For all species, both species richness and Shannon-Wiener (H’) were significantly higher in the L. camara invaded condition compared to the uninvaded condition. The Simpson’s (J’) and Pielou’s evenness (D’) indices, however, showed no differences between the invasion conditions. Furthermore, the effects of L. camara on vegetation cover were growth form-dependent, with differences being noted for trees and shrubs but not for graminoids and forbs. Changes in vegetation structure and composition were also noted where L. camara created favourable conditions for some species to co-occur with it, meaning that its known trait of changing soil physicochemical properties could benefit some species. Generally, the results of this study showed that the effects of L. camara on vegetation are varied and do not have a predictable pattern, so they should not be generalised. The findings (Chapter 5) also indicate that the L. camara invasion had a negative impact on seedling abundance and composition but not species diversity and richness. This is evident through the decrease in seedling abundance of forbs and graminoids in the L. camara invaded condition. Lantana camara also acted as a refuge for some plant species, mostly native forbs and grasses, including Aptenia cordifolia, Chamaesyce prostrata, Oxalis spp., and Setaria spp., as well as alien forbs such as Bidens pilosa, Plantago lanceolata, and Taraxacum officinale, suggesting L. camara does not entirely eliminate less competitive plant species but can co-exist with them. Lantana camara also displaced some native species, and this could be associated with their displacement in the standing vegetation. Moreover, the species also displaced the seed banks of some alien species, thus showing its competitive ability. Overall, L. camara invasion negatively influenced soil seed bank seedling abundance and composition of some species, but not diversity and richness. The results in Chapter 6 indicated that clearing L. camara is an effective method for reducing its population. However, our findings suggest that clearing alone may not be enough to re-establish these communities with native species. This is because the results of this study showed varied changes in soil properties and native vegetation (species richness, species diversity, percentage cover, and composition) after L. camara clearing. For example, soil moisture and soil penetration resistance showed no significant differences among the invasion conditions; only monthly variations were observed. This is an indication that seasonality influenced these properties. Significantly lower soil infiltration rates were observed in the cleared condition compared to the other conditions and were influenced by the months and the interaction of the clearing conditions and months. The water droplet penetration time showed no significant difference among the clearing conditions over the three months, and all the soil collected from the three clearing conditions was mostly wettable. Soil chemical properties showed that the L. camara invaded and cleared conditions had significantly lower soil pH compared to the uninvaded condition, and an increase in soil pH was observed after clearing L. camara. Vegetation characteristics showed that both the Shannon-Wiener index (H') and the Simpson’s index (D') were lower in the invaded and cleared conditions compared to the uninvaded condition, and significant differences were observed. A slight increase in the H' and D' indices was also observed after clearing L. camara. The mean percentage cover for trees and shrubs was significantly higher in the invaded condition than in the cleared and uninvaded conditions. However, the mean percentage cover of forbs and graminoids was similar among the invaded, cleared, and uninvaded conditions, and no significant differences were observed. When L. camara was cleared, native species recovery was observed and was more notable in the understory species. Overall, some signs of vegetation recovery were observed, although challenges such as secondary invaders and re-invasion by L. camara were noted in the cleared areas. This chapter then concluded that active restoration interventions should be incorporated during restoration to fast-track soil and vegetation recovery. The findings of this thesis will make several significant contributions to the field of biological invasions and provide baseline information that can be used in future studies. These are discussed in the various research chapters. Overall, the thesis concludes that L. camara invasion has varied impacts on native vegetation and soil, and its clearance, should be prioritised to reduce the negative impacts. However, L. camara cleared areas (by WfW in South Africa) require follow-up and monitoring at an early stage to assess vegetation and soil restoration success. In addition, active management measures after L. camara’s removal should be considered for clearing programmes to yield positive ecosystem recovery. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Bolosha, Uviwe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466524 , vital:76738 , DOI https://doi.org/10.21504/10962/466524
- Description: Invasive alien plants (IAPs) are one of the major contributing factors to biodiversity loss, and Lantana camara is among the top ten alien invaders worldwide. Lantana camara threatens native biodiversity and human health, prevents natural succession, and has an economic and environmental impact globally. With current climate change and future predictions, these IAPs are anticipated to continue posing huge threats to ecosystem composition, structure, and function. Even though L. camara is a widespread IAP, there is still limited knowledge in South Africa on how it influences soil physicochemical properties at the species level, vegetation communities, and soil seed banks at the community level following its invasion. There is also minimal knowledge on the management and control (i.e., clearing for restoration purposes) of L. camara in South Africa, especially in the Eastern Cape province of South Africa. To address the knowledge gap, this thesis was structured into three main aspects: understanding L. camara invasion mechanisms, evaluating invasion impacts on both the aboveground and belowground communities, and invasion management. The main objectives of this thesis were (i) to examine how L. camara invasion (at a species level) affected soil physicochemical properties across different seasons, (ii) to assess how L. camara influences natural vegetation (at a community level), (iii) to examine the effects of L. camara invasion (at the community level) on belowground soil seed banks and also assess the availability of pioneer native species and IAPs in the soil seed banks, and (iv) to evaluate soil and vegetation responses following L. camara clearing in comparison to invaded and uninvaded conditions. To answer these objectives, different studies were carried out in the Eastern Cape province, South Africa, on various farms within the Albany Thicket Biome. The results (Chapter 3) show that L. camara alters and modifies some soil physical properties, such as soil infiltration rate, repellency, and soil penetration resistance, in the communities it invades. A significant decrease in soil penetration under the L. camara canopy was observed compared to soils from the edge and out position. Moreover, significantly faster infiltration rates were observed in the canopy and edge positions than in the out position. The study also observed that these modifications in soil physical properties vary depending on the season. A seasonal comparison in soil penetration showed that soil was more compact in the dry season than the wet season, and significantly faster infiltration rates were observed in summer than in the other seasons. The soil collected under the invaded sampling positions was mostly wettable (80–100%), and not strongly, severely, or extremely repellent across all the seasons. The changes in soil properties caused by L. camara could create favourable conditions for its growth and invasion. Seasonal changes in soil properties also highlight how environmental conditions, especially temperature and rainfall patterns, can affect soil physical properties. The findings in Chapter 4 observed both the negative and positive impacts of L. camara, where the species did not have negative effects on species richness, diversity, or cover of some native species growth forms (i.e., graminoids and forbs). For all species, both species richness and Shannon-Wiener (H’) were significantly higher in the L. camara invaded condition compared to the uninvaded condition. The Simpson’s (J’) and Pielou’s evenness (D’) indices, however, showed no differences between the invasion conditions. Furthermore, the effects of L. camara on vegetation cover were growth form-dependent, with differences being noted for trees and shrubs but not for graminoids and forbs. Changes in vegetation structure and composition were also noted where L. camara created favourable conditions for some species to co-occur with it, meaning that its known trait of changing soil physicochemical properties could benefit some species. Generally, the results of this study showed that the effects of L. camara on vegetation are varied and do not have a predictable pattern, so they should not be generalised. The findings (Chapter 5) also indicate that the L. camara invasion had a negative impact on seedling abundance and composition but not species diversity and richness. This is evident through the decrease in seedling abundance of forbs and graminoids in the L. camara invaded condition. Lantana camara also acted as a refuge for some plant species, mostly native forbs and grasses, including Aptenia cordifolia, Chamaesyce prostrata, Oxalis spp., and Setaria spp., as well as alien forbs such as Bidens pilosa, Plantago lanceolata, and Taraxacum officinale, suggesting L. camara does not entirely eliminate less competitive plant species but can co-exist with them. Lantana camara also displaced some native species, and this could be associated with their displacement in the standing vegetation. Moreover, the species also displaced the seed banks of some alien species, thus showing its competitive ability. Overall, L. camara invasion negatively influenced soil seed bank seedling abundance and composition of some species, but not diversity and richness. The results in Chapter 6 indicated that clearing L. camara is an effective method for reducing its population. However, our findings suggest that clearing alone may not be enough to re-establish these communities with native species. This is because the results of this study showed varied changes in soil properties and native vegetation (species richness, species diversity, percentage cover, and composition) after L. camara clearing. For example, soil moisture and soil penetration resistance showed no significant differences among the invasion conditions; only monthly variations were observed. This is an indication that seasonality influenced these properties. Significantly lower soil infiltration rates were observed in the cleared condition compared to the other conditions and were influenced by the months and the interaction of the clearing conditions and months. The water droplet penetration time showed no significant difference among the clearing conditions over the three months, and all the soil collected from the three clearing conditions was mostly wettable. Soil chemical properties showed that the L. camara invaded and cleared conditions had significantly lower soil pH compared to the uninvaded condition, and an increase in soil pH was observed after clearing L. camara. Vegetation characteristics showed that both the Shannon-Wiener index (H') and the Simpson’s index (D') were lower in the invaded and cleared conditions compared to the uninvaded condition, and significant differences were observed. A slight increase in the H' and D' indices was also observed after clearing L. camara. The mean percentage cover for trees and shrubs was significantly higher in the invaded condition than in the cleared and uninvaded conditions. However, the mean percentage cover of forbs and graminoids was similar among the invaded, cleared, and uninvaded conditions, and no significant differences were observed. When L. camara was cleared, native species recovery was observed and was more notable in the understory species. Overall, some signs of vegetation recovery were observed, although challenges such as secondary invaders and re-invasion by L. camara were noted in the cleared areas. This chapter then concluded that active restoration interventions should be incorporated during restoration to fast-track soil and vegetation recovery. The findings of this thesis will make several significant contributions to the field of biological invasions and provide baseline information that can be used in future studies. These are discussed in the various research chapters. Overall, the thesis concludes that L. camara invasion has varied impacts on native vegetation and soil, and its clearance, should be prioritised to reduce the negative impacts. However, L. camara cleared areas (by WfW in South Africa) require follow-up and monitoring at an early stage to assess vegetation and soil restoration success. In addition, active management measures after L. camara’s removal should be considered for clearing programmes to yield positive ecosystem recovery. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Interaction of Arbuscular Mycorrhiza and Solanum Tuberosum
- Authors: Chifetete, Varaidzo Winnie
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466513 , vital:76737
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Chifetete, Varaidzo Winnie
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466513 , vital:76737
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Modelling water quality dynamics by integrating PYWR, climate change, and land-cover scenarios: a case study in the Grootdraai Dam Catchment, Upper Vaal, South Africa
- Authors: Lazar, Sofia
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465000 , vital:76564
- Description: Water resource management faces global challenges in allocation, quality, and sustainability. Despite extensive focus on quantity, water quality remains neglected, especially in developing nations, owing to data scarcity and funding issues. Water quantity modelling is more advanced, leaving water quality modelling lagging, as it requires finer spatiotemporal scales. Global water quality models, including those used in South Africa, encounter complexity and data requirements, and some proprietary models limit access. In South Africa, a water quality model is integrated with the less accessible Water Resources Yield Model (WRYM). However, WRYM's spatial lumping may not suffice for water quality assessment, emphasising the need for improvement. This study aims to address the gap in water quality modelling by transitioning from lumped, proprietary, and monthly time-step models applied in South Africa to more spatially distributed, user-friendly, transparent, fast models and daily time-step models, using the Grootdraai Dam Catchment in the Upper Vaal as a study region. The study examines providing water quality simulation for various variables under different tested scenarios, including (i) land-use scenarios (e.g., urbanisation, industrialisation, population growth and expansion in agricultural areas); (ii) mixed scenarios (e.g., climate change, mine closure, and demand increase). The study proposed a framework shifting from the WRYM to a Python water resources (Pywr) model, linked with the Water Quality Systems Assessment Model (WQSAM) in the Grootdraai Dam Catchment. This integration, the Python water resources-Water Quality (Pywr-WQ) model, was developed by the Water Research centre (WRc) in the United Kingdom. The study employed multiple regression models to develop land-use models, the outcomes of which were integrated into the Pywr-WQ model for medium and long term land-use scenario predictions. The study resulted in the following findings: (1) significant patterns emerge concerning the impacts of urbanisation, mining, and agricultural expansion on water quality; (2) urban areas exhibit elevated levels of nitrate plus nitrite and ammonium over the long term associated with human activities and infrastructure development; (3) increased cultivation leads to heightened phosphate levels, indicative of agricultural runoff and potential high fertiliser usage, while the expansion of mining activities results in elevated concentrations of sulphate and Total Dissolved Solids (TDS), attributed to the discharge of mine effluents; (4) noticeable declines in the concentrations of TDS and sulphate are evident in the medium to long term when compared to the baseline simulations. However, the worst-case scenario (i.e., a 70% abstraction increase) exhibits elevated peaks and concentrations compared to scenarios with more probable demand increases (e.g., a 5% increase). , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Lazar, Sofia
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465000 , vital:76564
- Description: Water resource management faces global challenges in allocation, quality, and sustainability. Despite extensive focus on quantity, water quality remains neglected, especially in developing nations, owing to data scarcity and funding issues. Water quantity modelling is more advanced, leaving water quality modelling lagging, as it requires finer spatiotemporal scales. Global water quality models, including those used in South Africa, encounter complexity and data requirements, and some proprietary models limit access. In South Africa, a water quality model is integrated with the less accessible Water Resources Yield Model (WRYM). However, WRYM's spatial lumping may not suffice for water quality assessment, emphasising the need for improvement. This study aims to address the gap in water quality modelling by transitioning from lumped, proprietary, and monthly time-step models applied in South Africa to more spatially distributed, user-friendly, transparent, fast models and daily time-step models, using the Grootdraai Dam Catchment in the Upper Vaal as a study region. The study examines providing water quality simulation for various variables under different tested scenarios, including (i) land-use scenarios (e.g., urbanisation, industrialisation, population growth and expansion in agricultural areas); (ii) mixed scenarios (e.g., climate change, mine closure, and demand increase). The study proposed a framework shifting from the WRYM to a Python water resources (Pywr) model, linked with the Water Quality Systems Assessment Model (WQSAM) in the Grootdraai Dam Catchment. This integration, the Python water resources-Water Quality (Pywr-WQ) model, was developed by the Water Research centre (WRc) in the United Kingdom. The study employed multiple regression models to develop land-use models, the outcomes of which were integrated into the Pywr-WQ model for medium and long term land-use scenario predictions. The study resulted in the following findings: (1) significant patterns emerge concerning the impacts of urbanisation, mining, and agricultural expansion on water quality; (2) urban areas exhibit elevated levels of nitrate plus nitrite and ammonium over the long term associated with human activities and infrastructure development; (3) increased cultivation leads to heightened phosphate levels, indicative of agricultural runoff and potential high fertiliser usage, while the expansion of mining activities results in elevated concentrations of sulphate and Total Dissolved Solids (TDS), attributed to the discharge of mine effluents; (4) noticeable declines in the concentrations of TDS and sulphate are evident in the medium to long term when compared to the baseline simulations. However, the worst-case scenario (i.e., a 70% abstraction increase) exhibits elevated peaks and concentrations compared to scenarios with more probable demand increases (e.g., a 5% increase). , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
Learning to make a difference: Small-scale women farmers in social learning spaces for climate action
- Authors: Chanyau, Ludwig
- Date: 2023-10-13
- Subjects: Social learning South Africa Amathole District Municipality , Value creation , Environmental education South Africa Amathole District Municipality , Climatic changes Study and teaching South Africa Amathole District Municipality , Communities of practice , Crops and climate South Africa Amathole District Municipality , Women farmers South Africa Amathole District Municipality , Farms, Small South Africa , Agricultural ecology South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402944 , vital:69908 , DOI 10.21504/10962/402944
- Description: How do women farmers in Africa learn about climate change? What is quality climate change learning for farmers? How do farmers interface new knowledge with their long-held and trusted traditional knowledge? How do we evaluate learning at farm level and beyond? Using Okoli’s theory mining review, I untangled a tripartite knot of social learning literature to find Social Learning Theory (SLT) suitable for a study to explore my practical and scholarly curiosity as reflected in the above questions. Wenger’s theory of Social Learning emerged as the most appropriate for my research. The second phase of my study explored the climate change learning and practice terrain for small-scale women farmers, analysing the connection between learning, practice, and the resultant value in two case study areas, municipalities in the Amathole District of the Eastern Cape Province of South Africa. In addition to a paper on SLT mining review that unravels and chooses between the strands of social learning, the two case studies resulted in three articles that responded to the study’s objectives and the research questions. The thesis is introduced and synthesised through five 'book-end' chapters, as well as through these four articles. What were my findings? In the first case study, in the drought-stricken Raymond Mhlaba Municipality, I gathered the data through individual semi-structured interviews with farmers, extension officers and representatives of the involved organisations. I also conducted a group interview with farmers and analysed documents to supplement interview data. I analysed the data using concepts of Communities of Practice (CoP) and SLT to map out the learning and practice landscape. I discovered a constellation of CoPs interconnected by the shared drive for adaptive water management. The constellation is made up of tertiary institutions, government departments, non-governmental organisations and farmers of varying experiences and competencies, with women emerging as the more proactive gender, and state-led extension services being willing but overstretched and under-resourced. SLT effectively traced the apparent fragmented learning within and outside the CoPs and the sudden and extensive shifts in the CoP boundaries, especially in the context of COVID-19 pandemic lockdowns and the increased adoption of digital learning platforms. Despite the richness and diversity brought by the emergent new learning networks that involve participants in the province and further afield, the adoption of digital learning platforms worsened the existing generational digital divide among farmers. iii In the second case study, in the water scarce Buffalo City Metropolitan Municipality, I adopted the Value Creation Framework (VCF) to conduct an ethnographic evaluation that used semi-structured interviews, participant observation and document analysis of the learning experiences of women farmers in a social movement on agroecology. I found that the farmer-centred learning approach of the movement has created value for the farmers involved, evidenced by the adoption of agroecology by over 2700 members (including new urban farmers who are occupying open spaces typically used as dumpsites). The learning approach has facilitated expansive learning, enhanced resource mobilisation, new collaborations, partnerships, and seed sharing networks. Additionally, it necessitated context-appropriate and transformative changes to intersectional justice issues associated with historical inequalities in access to land and water and gender discrimination, leading to improved practices, new access to markets and improved quality yields. These are examples of immediate, potential, applied, realised, orienting, enabling and transformative as well as strategic value, as defined by the VCF. In reflecting on how women farmers learn in these social learning spaces I elucidate the learning impact pathways and local contextual influences in shifting CoP boundaries, domains, and practices during the climate crisis as it intersects with other compounding factors. I generated insights that could be useful for stakeholders in the agricultural (extension) sector to build better pathways for emancipatory and empowering expansive social learning in contexts characterised by resource constraints, but also by strong women-led agency. Such learning could make a difference and cushion small-scale farming from collapse especially in times of unprecedented changes. The agroecology movement and associated communities of practice explored in this study create transformative social learning spaces that are able to respond to climate change, and hence a model that state-led extension might want to adopt in other resource-constrained contexts. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Chanyau, Ludwig
- Date: 2023-10-13
- Subjects: Social learning South Africa Amathole District Municipality , Value creation , Environmental education South Africa Amathole District Municipality , Climatic changes Study and teaching South Africa Amathole District Municipality , Communities of practice , Crops and climate South Africa Amathole District Municipality , Women farmers South Africa Amathole District Municipality , Farms, Small South Africa , Agricultural ecology South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402944 , vital:69908 , DOI 10.21504/10962/402944
- Description: How do women farmers in Africa learn about climate change? What is quality climate change learning for farmers? How do farmers interface new knowledge with their long-held and trusted traditional knowledge? How do we evaluate learning at farm level and beyond? Using Okoli’s theory mining review, I untangled a tripartite knot of social learning literature to find Social Learning Theory (SLT) suitable for a study to explore my practical and scholarly curiosity as reflected in the above questions. Wenger’s theory of Social Learning emerged as the most appropriate for my research. The second phase of my study explored the climate change learning and practice terrain for small-scale women farmers, analysing the connection between learning, practice, and the resultant value in two case study areas, municipalities in the Amathole District of the Eastern Cape Province of South Africa. In addition to a paper on SLT mining review that unravels and chooses between the strands of social learning, the two case studies resulted in three articles that responded to the study’s objectives and the research questions. The thesis is introduced and synthesised through five 'book-end' chapters, as well as through these four articles. What were my findings? In the first case study, in the drought-stricken Raymond Mhlaba Municipality, I gathered the data through individual semi-structured interviews with farmers, extension officers and representatives of the involved organisations. I also conducted a group interview with farmers and analysed documents to supplement interview data. I analysed the data using concepts of Communities of Practice (CoP) and SLT to map out the learning and practice landscape. I discovered a constellation of CoPs interconnected by the shared drive for adaptive water management. The constellation is made up of tertiary institutions, government departments, non-governmental organisations and farmers of varying experiences and competencies, with women emerging as the more proactive gender, and state-led extension services being willing but overstretched and under-resourced. SLT effectively traced the apparent fragmented learning within and outside the CoPs and the sudden and extensive shifts in the CoP boundaries, especially in the context of COVID-19 pandemic lockdowns and the increased adoption of digital learning platforms. Despite the richness and diversity brought by the emergent new learning networks that involve participants in the province and further afield, the adoption of digital learning platforms worsened the existing generational digital divide among farmers. iii In the second case study, in the water scarce Buffalo City Metropolitan Municipality, I adopted the Value Creation Framework (VCF) to conduct an ethnographic evaluation that used semi-structured interviews, participant observation and document analysis of the learning experiences of women farmers in a social movement on agroecology. I found that the farmer-centred learning approach of the movement has created value for the farmers involved, evidenced by the adoption of agroecology by over 2700 members (including new urban farmers who are occupying open spaces typically used as dumpsites). The learning approach has facilitated expansive learning, enhanced resource mobilisation, new collaborations, partnerships, and seed sharing networks. Additionally, it necessitated context-appropriate and transformative changes to intersectional justice issues associated with historical inequalities in access to land and water and gender discrimination, leading to improved practices, new access to markets and improved quality yields. These are examples of immediate, potential, applied, realised, orienting, enabling and transformative as well as strategic value, as defined by the VCF. In reflecting on how women farmers learn in these social learning spaces I elucidate the learning impact pathways and local contextual influences in shifting CoP boundaries, domains, and practices during the climate crisis as it intersects with other compounding factors. I generated insights that could be useful for stakeholders in the agricultural (extension) sector to build better pathways for emancipatory and empowering expansive social learning in contexts characterised by resource constraints, but also by strong women-led agency. Such learning could make a difference and cushion small-scale farming from collapse especially in times of unprecedented changes. The agroecology movement and associated communities of practice explored in this study create transformative social learning spaces that are able to respond to climate change, and hence a model that state-led extension might want to adopt in other resource-constrained contexts. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-10-13
Selection of DNA aptamers against Cancer-Targeting Murine Antibodies
- Authors: Nisbet, Laura Jade
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422426 , vital:71941
- Description: Access restricted. Access embargoed until 2025. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Nisbet, Laura Jade
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422426 , vital:71941
- Description: Access restricted. Access embargoed until 2025. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-03-29
Caring behaviour of midwives who nurse woman during childbirth in Botswana
- Authors: Potokwane, Nancy Osupile
- Date: 2022-12
- Subjects: Midwives , Childbirth, Botswana
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/59821 , vital:62437
- Description: Caring behaviour, which is defined as nurturing another to whom one feels a personal sense of commitment and responsibility, is fundamental to the psychosocial component of midwifery. Midwives ought to show respect, kindness and continuous psychosocial support during childbirth to women, who have the right to receive the highest possible standard of care and to be treated with dignity and respect before, during and after childbirth. However, an increasing number of complaints of the uncaring behaviour of midwives towards labouring women has indicated a problem that has not been fully researched. Therefore, the study aimed to identify and describe caring behaviours in the context of midwives in Botswana; determine the inhibiting factors of caring behaviours of midwives during childbirth; and make recommendations to midwives and unit managers based on Swanson’s (1991) Theory of Caring, which might lead to the optimisation of caring behaviour in Botswana midwives. A quantitative, descriptive research design was followed to answer the research questions, and a structured, self-administered questionnaire, which had been developed by the researcher based on the literature review, was used to capture data. A purposive sampling method was used to select 200 respondents working in maternity units in the Kgatleng and Greater Gaborone regional health districts in Botswana. The questionnaire was evaluated for reliability and validity to ensure that it consistently and accurately measured what it was intended to measure. A pilot study was conducted with 10 midwives who met the criteria for participation in the study to pre-test the feasibility of the questionnaire in preparation for the main study. In addition, ethical principles, such as informed consent, respect for persons, anonymity, confidentiality and beneficence were followed throughout the study. The questionnaire consisted of questions and statements. It was divided into three sections. Section A: Demographic attributes; Section B: Identification and description of the caring behaviour of midwives: Section C: Determination of the inhibiting factors of caring behaviours in midwifery. The data provided by the respondent’s answers to the questionnaires were statistically analysed using the Statistical Package for Social Science (SPSS®): Version 27 with the assistance of a statistician, thereby generating descriptive and inferential statistics. v The results of the data analysis revealed that most of the respondents provided positive responses, thereby indicating caring behaviour in midwifery practice. However, several factors that inhibit the caring behaviour of midwives were identified, such as a shortage of staff, work overload, a poor working environment, the inconsistent selection of staff for professional development, a lack of equipment, the young age of some of the woman (less than 15 years), the parity of the woman (more than one child) and the negative behaviour of many of the women. Therefore, recommendations for midwives and unit managers based on the five processes of Swanson’s (1991) Theory of Caring were made that could be used to optimise midwifery care in Botswana. , Thesis (MNurs)-- Faculty of Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Potokwane, Nancy Osupile
- Date: 2022-12
- Subjects: Midwives , Childbirth, Botswana
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/59821 , vital:62437
- Description: Caring behaviour, which is defined as nurturing another to whom one feels a personal sense of commitment and responsibility, is fundamental to the psychosocial component of midwifery. Midwives ought to show respect, kindness and continuous psychosocial support during childbirth to women, who have the right to receive the highest possible standard of care and to be treated with dignity and respect before, during and after childbirth. However, an increasing number of complaints of the uncaring behaviour of midwives towards labouring women has indicated a problem that has not been fully researched. Therefore, the study aimed to identify and describe caring behaviours in the context of midwives in Botswana; determine the inhibiting factors of caring behaviours of midwives during childbirth; and make recommendations to midwives and unit managers based on Swanson’s (1991) Theory of Caring, which might lead to the optimisation of caring behaviour in Botswana midwives. A quantitative, descriptive research design was followed to answer the research questions, and a structured, self-administered questionnaire, which had been developed by the researcher based on the literature review, was used to capture data. A purposive sampling method was used to select 200 respondents working in maternity units in the Kgatleng and Greater Gaborone regional health districts in Botswana. The questionnaire was evaluated for reliability and validity to ensure that it consistently and accurately measured what it was intended to measure. A pilot study was conducted with 10 midwives who met the criteria for participation in the study to pre-test the feasibility of the questionnaire in preparation for the main study. In addition, ethical principles, such as informed consent, respect for persons, anonymity, confidentiality and beneficence were followed throughout the study. The questionnaire consisted of questions and statements. It was divided into three sections. Section A: Demographic attributes; Section B: Identification and description of the caring behaviour of midwives: Section C: Determination of the inhibiting factors of caring behaviours in midwifery. The data provided by the respondent’s answers to the questionnaires were statistically analysed using the Statistical Package for Social Science (SPSS®): Version 27 with the assistance of a statistician, thereby generating descriptive and inferential statistics. v The results of the data analysis revealed that most of the respondents provided positive responses, thereby indicating caring behaviour in midwifery practice. However, several factors that inhibit the caring behaviour of midwives were identified, such as a shortage of staff, work overload, a poor working environment, the inconsistent selection of staff for professional development, a lack of equipment, the young age of some of the woman (less than 15 years), the parity of the woman (more than one child) and the negative behaviour of many of the women. Therefore, recommendations for midwives and unit managers based on the five processes of Swanson’s (1991) Theory of Caring were made that could be used to optimise midwifery care in Botswana. , Thesis (MNurs)-- Faculty of Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-12
A comparative appraisal of access and quality of sexual and reproductive health services for gays and lesbians in Bulawayo (Zimbabwe) and Pretoria (South Africa)
- Authors: Jasi, Phineas
- Date: 2021-11
- Subjects: Reproductive health , Sexual health
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21959 , vital:51854
- Description: This study investigated the extent to which gays and lesbians access quality sexual and reproductive health (SRH) services in Pretoria and Bulawayo. The study also examines the facilitators and barriers for accessing the same services. Theoretically, the study was grounded in the Health Belief Model (Hochbaum, 1958, modified by Rosenstock, 1974 and Siddiqui, 2016). To answer the research questions, a mixed methods approach was applied involving both qualitative and quantitative data collection methods. A total of 30 key informant interviews, eight focus group discussions and 387 questionnaires were administered using purposive, time location and snowball sampling approaches in the two cities. The study found that the most commonly available sexual and reproductive health (SRH) services were contraceptive services, sexually transmitted infections (STI) services and Human immunodeficiency syndrome (HIV) services. The services were provided at public health facilities, drop-in centres and through outreach activities operated by Civil Society Organizations (CSOs). The least available services that gays and lesbians required as part of a comprehensive package were access to information, education and communications (IEC) materials and mental health and psychosocial support services (MHPSS). Several service providers were not adhering to the World Health Organization (WHO) guidelines for provision of comprehensive services for key populations including gays and lesbians. Critical gaps noted included the absence of key populations-only service hours, lack of options for clinicians to attend to them, presence of a stigma and discrimination free environment and provision of comprehensive package of services under one roof. Most of the referral facilities had limited drugs, equipment and supplies for cancer screening and they had no HIV prevention, sex change, in-vitro fertilization, and sterilization services and procedures. The quality of physical facilities and SRH services in both cities did not meet the expectations of gays and lesbians, acting as a barrier to their health seeking behaviour. Stigma and discrimination from healthcare workers was a huge barrier affecting access across all public health facilities. The acts of stigmatisation and discrimination affected the perceptions that gays and lesbians had regarding the quality of the services and compromised access of the same. In view of these health system challenges, the study recommends that there is need for public authorities in both cities to address the bottlenecks and barriers affecting access to SRH services and products such as lubricants, affordable quality condoms, dental dams and latex gloves while reinforcing the facilitating factors promoting access. Healthcare workers need further training on how to provide comprehensive services for gays and lesbians according to the WHO guidelines. Public health authorities in Bulawayo and Pretoria should build upon the identified factors which facilitated the access to SRH services and use of products such as condoms and lubricants. These factors require strengthening of community-based organizations and networks that work directly with gays and lesbians in both Bulawayo and Pretoria. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2021
- Full Text:
- Date Issued: 2021-11
- Authors: Jasi, Phineas
- Date: 2021-11
- Subjects: Reproductive health , Sexual health
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21959 , vital:51854
- Description: This study investigated the extent to which gays and lesbians access quality sexual and reproductive health (SRH) services in Pretoria and Bulawayo. The study also examines the facilitators and barriers for accessing the same services. Theoretically, the study was grounded in the Health Belief Model (Hochbaum, 1958, modified by Rosenstock, 1974 and Siddiqui, 2016). To answer the research questions, a mixed methods approach was applied involving both qualitative and quantitative data collection methods. A total of 30 key informant interviews, eight focus group discussions and 387 questionnaires were administered using purposive, time location and snowball sampling approaches in the two cities. The study found that the most commonly available sexual and reproductive health (SRH) services were contraceptive services, sexually transmitted infections (STI) services and Human immunodeficiency syndrome (HIV) services. The services were provided at public health facilities, drop-in centres and through outreach activities operated by Civil Society Organizations (CSOs). The least available services that gays and lesbians required as part of a comprehensive package were access to information, education and communications (IEC) materials and mental health and psychosocial support services (MHPSS). Several service providers were not adhering to the World Health Organization (WHO) guidelines for provision of comprehensive services for key populations including gays and lesbians. Critical gaps noted included the absence of key populations-only service hours, lack of options for clinicians to attend to them, presence of a stigma and discrimination free environment and provision of comprehensive package of services under one roof. Most of the referral facilities had limited drugs, equipment and supplies for cancer screening and they had no HIV prevention, sex change, in-vitro fertilization, and sterilization services and procedures. The quality of physical facilities and SRH services in both cities did not meet the expectations of gays and lesbians, acting as a barrier to their health seeking behaviour. Stigma and discrimination from healthcare workers was a huge barrier affecting access across all public health facilities. The acts of stigmatisation and discrimination affected the perceptions that gays and lesbians had regarding the quality of the services and compromised access of the same. In view of these health system challenges, the study recommends that there is need for public authorities in both cities to address the bottlenecks and barriers affecting access to SRH services and products such as lubricants, affordable quality condoms, dental dams and latex gloves while reinforcing the facilitating factors promoting access. Healthcare workers need further training on how to provide comprehensive services for gays and lesbians according to the WHO guidelines. Public health authorities in Bulawayo and Pretoria should build upon the identified factors which facilitated the access to SRH services and use of products such as condoms and lubricants. These factors require strengthening of community-based organizations and networks that work directly with gays and lesbians in both Bulawayo and Pretoria. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2021
- Full Text:
- Date Issued: 2021-11
A self-emulsifying delivery system loaded with efavirenz: The case for flax-seed oil
- Authors: Mazonde, Priveledge
- Date: 2021-10-29
- Subjects: Drug delivery systems , Linseed oil , Antiretroviral agents , HIV (Viruses) , Drug carriers (Pharmacy) , Solubility , High performance liquid chromatography , Efavirenz
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192944 , vital:45283
- Description: The feasibility of incorporating efavirenz (EFV), an antiretroviral agent against HIV into a lipid-based self-emulsifying drug delivery system (SEDDS) containing vegetable oils was investigated. EFV has poor aqueous solubility and is classified under the Biopharmaceutical Classification System (BCS) as a class II compound with highly permeability, its aqueous solubility is less than 10 mg/ml and is defined as a practically insoluble compound with a consequent poor bioavailability of approximately 40%, and erratic dissolution behaviour. SEDDS formulations have been shown to improve the aqueous solubility and consequently the bioavailability of BCS II compounds such as EFV. EFV is a first line antiviral agent used in combination with other agents in antiretroviral therapy (ART). Among the number of NNRTIs approved for use in HIV treatment, EFV is one of the most commonly prescribed drug. Statistical methods and Design of Experiments (DoE) using Response Surface Methodology (RSM), specifically a Central Composite Design (CCD), were used to facilitate the development of a reversed-phase high performance liquid chromatographic (HPLC) method for the quantitation of EFV during formulation product and process development studies. A rapid, accurate, precise and sensitive HPLC method with ultraviolet (UV) detection was developed, optimised and validated for the in-vitro analysis of EFV in a total run time under 10 minutes for the elution of both EFV and loratidine which was used as the internal standard (IS). The method was then successfully applied to the determination of EFV in commercially available tablets. Excipient screening was undertaken using solubility studies and revealed that EFV had highest solubility in flaxseed oil in comparison to soybean, macadamia, grapeseed, sunflower and olive oils. The non-ionic Tween® 80 and Span® 20 were selected as surfactant and co-surfactant, respectively with ethanol co-solvent as they exhibited improved miscibility with co-solvent. Pre-formulation studies were undertaken to investigate the compatibility of the API with excipients and to identify a nano-emulsion region and other emulsion types using pseudoternary phase diagrams. The phase behaviour of crude cold pressed flaxseed oil with the selected non-ionic surfactants revealed an area within pseudo-ternary phase diagrams for different surfactant-mixtures formed gels/semisolid structures which can be exploited for other drug delivery strategies that require such properties. Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction (XRD) and Raman spectroscopy were used to identify and assess the compatibility of EFV with chosen excipients. 2 A reduction in the peak intensity was observed for EFV when combined with each hydrophobic/lipid excipient evaluated revealing that there was a marked reduction in the crystallinity of the EFV. A decrease in crystallinity in comparison with the bulk API may indicate that EFV were amorphous or sequestered in a molecular dispersion and exhibited an increased solubility for the molecule. Flaxseed oil was used as the oil phase in studies for the optimization of surfactant mixtures undertaken using DoE, specifically a D-optimal mixtures design with the flaxseed oil content set at 10% m/m was performed. Solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, drug loading capacity, Zeta Potential, droplet sizes and polydispersity index (PDI). Kinetically stable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and assessed. Droplet sizes ranged between 156 and 225 nm, Zeta Potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487. SEDDS formulations of EFV in nano-sized carriers were developed and optimised, in vitro drug release varied with varying amounts of ethanol in the formulation producing formulations that exhibited differently modulated drug in-vitro release profiles that may be further manipulated for better performance and therapeutic outcomes in terms of solubility and possibly bioavailability of EFV when delivered using SEDDS rather than using tablets which in turn may lead to better therapeutic outcomes for patients with HIV. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mazonde, Priveledge
- Date: 2021-10-29
- Subjects: Drug delivery systems , Linseed oil , Antiretroviral agents , HIV (Viruses) , Drug carriers (Pharmacy) , Solubility , High performance liquid chromatography , Efavirenz
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192944 , vital:45283
- Description: The feasibility of incorporating efavirenz (EFV), an antiretroviral agent against HIV into a lipid-based self-emulsifying drug delivery system (SEDDS) containing vegetable oils was investigated. EFV has poor aqueous solubility and is classified under the Biopharmaceutical Classification System (BCS) as a class II compound with highly permeability, its aqueous solubility is less than 10 mg/ml and is defined as a practically insoluble compound with a consequent poor bioavailability of approximately 40%, and erratic dissolution behaviour. SEDDS formulations have been shown to improve the aqueous solubility and consequently the bioavailability of BCS II compounds such as EFV. EFV is a first line antiviral agent used in combination with other agents in antiretroviral therapy (ART). Among the number of NNRTIs approved for use in HIV treatment, EFV is one of the most commonly prescribed drug. Statistical methods and Design of Experiments (DoE) using Response Surface Methodology (RSM), specifically a Central Composite Design (CCD), were used to facilitate the development of a reversed-phase high performance liquid chromatographic (HPLC) method for the quantitation of EFV during formulation product and process development studies. A rapid, accurate, precise and sensitive HPLC method with ultraviolet (UV) detection was developed, optimised and validated for the in-vitro analysis of EFV in a total run time under 10 minutes for the elution of both EFV and loratidine which was used as the internal standard (IS). The method was then successfully applied to the determination of EFV in commercially available tablets. Excipient screening was undertaken using solubility studies and revealed that EFV had highest solubility in flaxseed oil in comparison to soybean, macadamia, grapeseed, sunflower and olive oils. The non-ionic Tween® 80 and Span® 20 were selected as surfactant and co-surfactant, respectively with ethanol co-solvent as they exhibited improved miscibility with co-solvent. Pre-formulation studies were undertaken to investigate the compatibility of the API with excipients and to identify a nano-emulsion region and other emulsion types using pseudoternary phase diagrams. The phase behaviour of crude cold pressed flaxseed oil with the selected non-ionic surfactants revealed an area within pseudo-ternary phase diagrams for different surfactant-mixtures formed gels/semisolid structures which can be exploited for other drug delivery strategies that require such properties. Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction (XRD) and Raman spectroscopy were used to identify and assess the compatibility of EFV with chosen excipients. 2 A reduction in the peak intensity was observed for EFV when combined with each hydrophobic/lipid excipient evaluated revealing that there was a marked reduction in the crystallinity of the EFV. A decrease in crystallinity in comparison with the bulk API may indicate that EFV were amorphous or sequestered in a molecular dispersion and exhibited an increased solubility for the molecule. Flaxseed oil was used as the oil phase in studies for the optimization of surfactant mixtures undertaken using DoE, specifically a D-optimal mixtures design with the flaxseed oil content set at 10% m/m was performed. Solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, drug loading capacity, Zeta Potential, droplet sizes and polydispersity index (PDI). Kinetically stable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and assessed. Droplet sizes ranged between 156 and 225 nm, Zeta Potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487. SEDDS formulations of EFV in nano-sized carriers were developed and optimised, in vitro drug release varied with varying amounts of ethanol in the formulation producing formulations that exhibited differently modulated drug in-vitro release profiles that may be further manipulated for better performance and therapeutic outcomes in terms of solubility and possibly bioavailability of EFV when delivered using SEDDS rather than using tablets which in turn may lead to better therapeutic outcomes for patients with HIV. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2021
- Full Text:
- Date Issued: 2021-10-29
Baseline description of the Benthic Biotopes for two Long-Term Ecological Research (LTER) stations in Algoa Bay, Agulhas ecoregion, South Africa
- Authors: Parker-Nance, Shirley
- Date: 2021-10-29
- Subjects: Benthic ecology South Africa Algoa Bay , Long-Term Ecological Research Program , Marine invertebrates South Africa Algoa Bay , Reef ecology South Africa Algoa Bay , Coastal zone management South Africa Algoa Bay , Reef fishes South Africa Algoa Bay , Ecological mapping South Africa Algoa Bay
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191680 , vital:45147 , 10.21504/10962/191680
- Description: Shallow coastal marine ecosystems provide important resources to society but are increasingly under threat from anthropogenic impacts. These systems form an interface between land and sea, providing valuable resources. Global environmental change, overexploitation, habitat transformation, pollution and policies aimed at short-term socio-economic gains are driving the loss of natural resources, productivity and biodiversity. Consequently, a comprehensive and holistic understanding of the current and future states of marine ecosystems is essential. This requires insight into the processes involved in maintaining genetic, species, habitat, community and biotope diversity at an ecosystem level. An understanding of ecosystem processes and the ability to detect changes in biodiversity, biotopes, seascape composition and ecosystem functioning require observation made over time and space. In response to this need, Long-Term Ecological Research (LTER) programmes such as those established by the South African Environmental Observation Network (SAEON) supported by the Department of Science and Innovation’s (DSI) Shallow Marine and Coastal Research Infrastructure (SMCRI) collect long–term observational data from different environments and systems. This study aimed to evaluate data collected as part of the developmental phase of a newly established benthic research platform. The datasets constructed are used to develop a baseline description of the benthic biotopes of two study areas within Algoa Bay. It aimed to gain insight into the feasibility of the methods used and the value of the data and derived essential biological variables (EVB). Assessing the sustainability of the programme over time was done through a practical evaluation of the methodology to be used and the technical feasibility of data collection and analysis. It furthermore aimed to assess the data usefulness in describing biodiversity at various scales and its sensitivity in reporting change. This pilot study provides valuable insight into data collection methodologies and introduces new sampling platforms. The baseline dataset consisted of data collected during the first 18 months of the SAEON Benthic Ecosystem Long-Term Ecological Research (BELTER) platform in Algoa Bay, Agulhas ecoregion, Western Indian Ocean, South Africa. This comprised of the collection of images for 150 m2 of the researched benthic seascape and 306 stereo video data streams. The 77 760 point dataset allowed the identification of 12 substrate types, 7 biotopes, 44 sub-biotope units, 377 sessile and sedentary benthic species and 51 ichthyofauna species. The described habitat and benthic communities and the defined benthic biotopes allowed for the assessment of biotope heterogeneity and the construction of a provisional distribution map for the broader biotopes. This work includes a study into the infra- and supra-benthic ichthyofauna associated with the defined biotopes and investigates the role habitat and benthic communities play in the distribution of these fish 3 assemblages. Lastly, it assesses the value of morphological traits and diversity indices for describing and comparing abiotic and biotic components of observed systems within the shallow coastal marine seascape. This study shows that species composition differs significantly between biotopes with habitat type playing a key role in the composition of the benthos. Substrate type, consolidated or unconsolidated, depth and the composition of the soft sediment is the most important determining factors. The White Sands Reef station has a higher species diversity than the St Croix Island Complex station with a higher percentage cover associated with the hard substrate. The dissimilarity between biotopes and communities are generally high although similarity within the biotopes or communities was found to be relatively low. This was considered indicative of high heterogeneity within the biotopes and a patch or mosaic-like distribution of communities within the broader biotope. A fine-scale a posteriori analysis of the data collected confirmed the high heterogeneous nature of both habitat and communities within the broader biotope. The description of the abiotic and biotic variables resulted in the identification of a diverse suite of biotope subunits. The character of the biotope hinges not only on the composition of the substrate and biota present but the contribution of smaller distinct biotopes subunits, their distribution and representation within broader biotopes and the degree these are shared with other broader biotopes. The distribution of these biotope units at different scales is believed to be important in understanding inherent diversity, niche partitioning and connectivity within a highly heterogeneous seascape. Ichthyofauna associated with the broader biotopes were indicative of the substrate type. Low profile reef systems with interspaced sandy stretches supported both reef fish and those typically associated with sandy substrates. Benthic biotopes associated characteristically with higher profile reef systems and less sand or soft sediment were mainly utilized by reef-associated fish species. Substrate type, depth and seasonality were found to be important factors in the observed composition and distribution of ichthyofauna over the seascape. Although fish species were found to have a wide distribution and made use of multiple biotopes the average abundance of the species within the observed assemblages differed. Analysis of ichthyofauna species composition indicated that observed fish assemblages were homogeneous within five of the seven biotopes. Broader biotopes that were found to be significantly different between sample locations are characterised by a diverse complement of biotope subunits and are highly heterogeneous. Traits and diversity indices are important tools for assessing and comparing different systems within the seascape, both spatially and temporally. The classification of the biota into broader phylogenetic groups indicated a significant difference between biotopes. This is especially useful when detailed 4 analysis or species identification is not possible or the skill set is not available. Morphological traits included in this study informed on the physical structure of the communities present and in combination with substrate type provided insight into the three-dimensional structure of the biotope. Species diversity, abundance, density estimates and the Shannon-Weiner diversity index were found to be the most useful diversity indices characterising and comparing biotopes. This was less so for ichthyofauna. Significant differences in the number of species observed were evident only between consolidated and unconsolidated dominated substrates. Although there was no significant difference in the number of individuals observed, both the Shannon-Weiner and Simpson Diversity indices were able to highlight differences in the fish assemblages observed for the different biotopes. The data collected, although permitting a comprehensive baseline assessment of the benthic environment for two research stations within the SAEON Algoa Bay LTER Sentinel Site, is temporally limited. The ichthyofauna dataset used was small and it is understood that the addition of length-frequency analysis of observed ichthyofauna will benefit our understanding of the biotope use by infra- and supra-benthic fish species over their life history within the larger seascape. Seasonal differences were evident and it is expected that datasets spanning several years, including LTER stations within different marine ecosystems types, will provide valuable insights on system dynamics in the short and long term both spatially and temporally. This study is the first attempt to evaluate the methodology developed and data collected in the South African Environmental Observation Network’s, Elwandle Coastal Node as part of the Shallow Marine and Coastal Research Infrastructure Benthic Ecosystem Long-Term Ecological Research (BELTER) platform. Newly designed and developed sample equipment and a sampling regime allowed for the collection of data on a long-term basis. The study was successful in the description of the biotope and biotope subunits for two research stations in Algoa Bay. It permitted the construction of comprehensive species lists for both benthic sessile and sedentary biota and the associated ichthyofauna. The subset of data used was successful in reporting on both spatial and temporal change. This work demonstrates that in the absence of detailed species identifications, traits may be used to describe habitat and community structure and report on abiotic and biotic biotope characteristics. This study furthermore allowed for the comparison of a comprehensive suite of diversity indices highlighting indices that may be especially useful in routine BELTER reporting. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Parker-Nance, Shirley
- Date: 2021-10-29
- Subjects: Benthic ecology South Africa Algoa Bay , Long-Term Ecological Research Program , Marine invertebrates South Africa Algoa Bay , Reef ecology South Africa Algoa Bay , Coastal zone management South Africa Algoa Bay , Reef fishes South Africa Algoa Bay , Ecological mapping South Africa Algoa Bay
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191680 , vital:45147 , 10.21504/10962/191680
- Description: Shallow coastal marine ecosystems provide important resources to society but are increasingly under threat from anthropogenic impacts. These systems form an interface between land and sea, providing valuable resources. Global environmental change, overexploitation, habitat transformation, pollution and policies aimed at short-term socio-economic gains are driving the loss of natural resources, productivity and biodiversity. Consequently, a comprehensive and holistic understanding of the current and future states of marine ecosystems is essential. This requires insight into the processes involved in maintaining genetic, species, habitat, community and biotope diversity at an ecosystem level. An understanding of ecosystem processes and the ability to detect changes in biodiversity, biotopes, seascape composition and ecosystem functioning require observation made over time and space. In response to this need, Long-Term Ecological Research (LTER) programmes such as those established by the South African Environmental Observation Network (SAEON) supported by the Department of Science and Innovation’s (DSI) Shallow Marine and Coastal Research Infrastructure (SMCRI) collect long–term observational data from different environments and systems. This study aimed to evaluate data collected as part of the developmental phase of a newly established benthic research platform. The datasets constructed are used to develop a baseline description of the benthic biotopes of two study areas within Algoa Bay. It aimed to gain insight into the feasibility of the methods used and the value of the data and derived essential biological variables (EVB). Assessing the sustainability of the programme over time was done through a practical evaluation of the methodology to be used and the technical feasibility of data collection and analysis. It furthermore aimed to assess the data usefulness in describing biodiversity at various scales and its sensitivity in reporting change. This pilot study provides valuable insight into data collection methodologies and introduces new sampling platforms. The baseline dataset consisted of data collected during the first 18 months of the SAEON Benthic Ecosystem Long-Term Ecological Research (BELTER) platform in Algoa Bay, Agulhas ecoregion, Western Indian Ocean, South Africa. This comprised of the collection of images for 150 m2 of the researched benthic seascape and 306 stereo video data streams. The 77 760 point dataset allowed the identification of 12 substrate types, 7 biotopes, 44 sub-biotope units, 377 sessile and sedentary benthic species and 51 ichthyofauna species. The described habitat and benthic communities and the defined benthic biotopes allowed for the assessment of biotope heterogeneity and the construction of a provisional distribution map for the broader biotopes. This work includes a study into the infra- and supra-benthic ichthyofauna associated with the defined biotopes and investigates the role habitat and benthic communities play in the distribution of these fish 3 assemblages. Lastly, it assesses the value of morphological traits and diversity indices for describing and comparing abiotic and biotic components of observed systems within the shallow coastal marine seascape. This study shows that species composition differs significantly between biotopes with habitat type playing a key role in the composition of the benthos. Substrate type, consolidated or unconsolidated, depth and the composition of the soft sediment is the most important determining factors. The White Sands Reef station has a higher species diversity than the St Croix Island Complex station with a higher percentage cover associated with the hard substrate. The dissimilarity between biotopes and communities are generally high although similarity within the biotopes or communities was found to be relatively low. This was considered indicative of high heterogeneity within the biotopes and a patch or mosaic-like distribution of communities within the broader biotope. A fine-scale a posteriori analysis of the data collected confirmed the high heterogeneous nature of both habitat and communities within the broader biotope. The description of the abiotic and biotic variables resulted in the identification of a diverse suite of biotope subunits. The character of the biotope hinges not only on the composition of the substrate and biota present but the contribution of smaller distinct biotopes subunits, their distribution and representation within broader biotopes and the degree these are shared with other broader biotopes. The distribution of these biotope units at different scales is believed to be important in understanding inherent diversity, niche partitioning and connectivity within a highly heterogeneous seascape. Ichthyofauna associated with the broader biotopes were indicative of the substrate type. Low profile reef systems with interspaced sandy stretches supported both reef fish and those typically associated with sandy substrates. Benthic biotopes associated characteristically with higher profile reef systems and less sand or soft sediment were mainly utilized by reef-associated fish species. Substrate type, depth and seasonality were found to be important factors in the observed composition and distribution of ichthyofauna over the seascape. Although fish species were found to have a wide distribution and made use of multiple biotopes the average abundance of the species within the observed assemblages differed. Analysis of ichthyofauna species composition indicated that observed fish assemblages were homogeneous within five of the seven biotopes. Broader biotopes that were found to be significantly different between sample locations are characterised by a diverse complement of biotope subunits and are highly heterogeneous. Traits and diversity indices are important tools for assessing and comparing different systems within the seascape, both spatially and temporally. The classification of the biota into broader phylogenetic groups indicated a significant difference between biotopes. This is especially useful when detailed 4 analysis or species identification is not possible or the skill set is not available. Morphological traits included in this study informed on the physical structure of the communities present and in combination with substrate type provided insight into the three-dimensional structure of the biotope. Species diversity, abundance, density estimates and the Shannon-Weiner diversity index were found to be the most useful diversity indices characterising and comparing biotopes. This was less so for ichthyofauna. Significant differences in the number of species observed were evident only between consolidated and unconsolidated dominated substrates. Although there was no significant difference in the number of individuals observed, both the Shannon-Weiner and Simpson Diversity indices were able to highlight differences in the fish assemblages observed for the different biotopes. The data collected, although permitting a comprehensive baseline assessment of the benthic environment for two research stations within the SAEON Algoa Bay LTER Sentinel Site, is temporally limited. The ichthyofauna dataset used was small and it is understood that the addition of length-frequency analysis of observed ichthyofauna will benefit our understanding of the biotope use by infra- and supra-benthic fish species over their life history within the larger seascape. Seasonal differences were evident and it is expected that datasets spanning several years, including LTER stations within different marine ecosystems types, will provide valuable insights on system dynamics in the short and long term both spatially and temporally. This study is the first attempt to evaluate the methodology developed and data collected in the South African Environmental Observation Network’s, Elwandle Coastal Node as part of the Shallow Marine and Coastal Research Infrastructure Benthic Ecosystem Long-Term Ecological Research (BELTER) platform. Newly designed and developed sample equipment and a sampling regime allowed for the collection of data on a long-term basis. The study was successful in the description of the biotope and biotope subunits for two research stations in Algoa Bay. It permitted the construction of comprehensive species lists for both benthic sessile and sedentary biota and the associated ichthyofauna. The subset of data used was successful in reporting on both spatial and temporal change. This work demonstrates that in the absence of detailed species identifications, traits may be used to describe habitat and community structure and report on abiotic and biotic biotope characteristics. This study furthermore allowed for the comparison of a comprehensive suite of diversity indices highlighting indices that may be especially useful in routine BELTER reporting. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
A model for smart factories in the consumer health sector
- Authors: Nherera, Bruce
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52959 , vital:44879
- Description: The manufacturing sector, globally, is facing significant challenges due to current societal, economic, environmental, and technological developments. To overcome the challenges into the future, manufacturing organisations will need new capabilities to manage their end to end supply chains to make sure that it is responsive and agile. The Smart factories, as an element of Industry 4.0, drive efficient operations while at the same time ensure that employees are safe, and operations are environmentally sustainable. The ability to be flexible, to be reconfigured and to be connected to customers allows Smart factories to mass customise their customers’ orders and maintain the same efficiencies when compared to mass production operations. Technologies such as the Internet of Things (IoT) in Smart factories must be employed to further drive efficiencies, agility and ease of production by giving operations the capability to respond in real time to problems with machines and customer requests. Smart factory technology allows operational sustainability through the efficient use of resources. The Smart factory revolution is significantly changing the relationship between humans and machines. Based on the literature review conducted, a theoretical model was constructed which was tested at a Consumer Health Organisation to identify the relationship between the dependent and independent factors. The independent factors, specified in the model were job security, organisation culture, training and skills, trust, costs and resources, parent company and standards. , Thesis (MBA) -- Faculty of Business and Economic Sciences, NMU Business School, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Nherera, Bruce
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52959 , vital:44879
- Description: The manufacturing sector, globally, is facing significant challenges due to current societal, economic, environmental, and technological developments. To overcome the challenges into the future, manufacturing organisations will need new capabilities to manage their end to end supply chains to make sure that it is responsive and agile. The Smart factories, as an element of Industry 4.0, drive efficient operations while at the same time ensure that employees are safe, and operations are environmentally sustainable. The ability to be flexible, to be reconfigured and to be connected to customers allows Smart factories to mass customise their customers’ orders and maintain the same efficiencies when compared to mass production operations. Technologies such as the Internet of Things (IoT) in Smart factories must be employed to further drive efficiencies, agility and ease of production by giving operations the capability to respond in real time to problems with machines and customer requests. Smart factory technology allows operational sustainability through the efficient use of resources. The Smart factory revolution is significantly changing the relationship between humans and machines. Based on the literature review conducted, a theoretical model was constructed which was tested at a Consumer Health Organisation to identify the relationship between the dependent and independent factors. The independent factors, specified in the model were job security, organisation culture, training and skills, trust, costs and resources, parent company and standards. , Thesis (MBA) -- Faculty of Business and Economic Sciences, NMU Business School, 2021
- Full Text: false
- Date Issued: 2021-04
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