Showing items 141 - 160 of 3572

An evaluation of the effectiveness of area-based conservation interventions in avoiding biodiversity loss in South Africa

  • Authors: Von Staden, Lize
  • Date: 2023-04
  • Subjects: Environmental policy , Conservation of natural resources -- Government policy -- South Africa
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/61115 , vital:69762
  • Description: Counterfactual impact evaluation studies form an important evidence base for the effectiveness of conservation projects, programs, and policies (collectively referred to as conservation interventions). In South Africa, counterfactual impact evaluation methods have rarely been applied to local conservation interventions, and therefore evidence for the effectiveness of key strategic national conservation approaches is lacking. This study evaluated three area-based interventions that together aim to avoid the loss of areas most important for the persistence of biodiversity in the terrestrial realm as evidence towards the effectiveness of South Africa’s landscape approach to biodiversity conservation. The first intervention, South Africa’s National Protected Area Expansion Strategy (NPAES), set ambitious targets to double the extent of South Africa’s protected area network while ensuring that the expansion preferentially occurs in areas of under-represented biodiversity. The strategy was evaluated in terms of its effectiveness in guiding protected area expansion towards more equitable representation of South Africa’s biodiversity through an assessment of changes in indicators of protected area expansion decision-making before and after the implementation of the strategy. The second intervention is the use of maps of biodiversity priorities to guide land use change decisions outside protected areas. Impact was evaluated as avoided loss of Critical Biodiversity Areas (CBAs), which need to remain in a natural condition to meet in situ conservation targets for species, ecosystems, and ecological processes. Avoided loss in CBAs was benchmarked against avoided loss in protected areas, to contextualize the effectiveness of land use planning as a conservation intervention. Lastly, the effectiveness of stricter land use regulations for threatened ecosystems to reduce land conversion pressure on these ecosystems was evaluated. Key findings were that protected areas are highly effective conservation interventions where they can be implemented, but their capacity for conservation impact is limited by severe constraints on strategic expansion. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
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  • Date Issued: 2023-04

An exploration of the Participatory Guarantee System (PGS) facilitating the growth and certification of small-scale organic farmers: Giyani, Garden Route and Overberg case studies

  • Authors: Mashele,N’wa-Jama
  • Date: 2023-04
  • Subjects: Organic farming – Case studies --South Africa , Organic farming research
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/60741 , vital:66574
  • Description: In this study, I evaluated the Participatory Guarantee System (PGS) as a framework to support the growth and certification of small-scale organic farmers. I used the interpretivism and constructivism lenses to understand the PGS from the perspective of members of three PGS groups. The research was qualitative, treating the three PGS groups as case studies. I collected data using focus groups, semi-structured interviews, questionnaires, field notes and observations. The theoretical frameworks that guided the research and data analysis were Socio-ecological Systems (SES) based principles and the Multi-Level-Perspective (MLP) framework. The data were analysed using Atlas.ti content analysis software. The key results were grouped into four themes: capacity; market and logistics; learning process; and disturbance, shock and stress. The theme of ‘capacity’ dealt with the functioning of a PGS, where three categories were identified: group composition and capacity; resource limitations and institutional support; marketing and consumer education. The more diversity in age, education and culture of PGS stakeholders, the better performance and chances of continuity and propagation. PGS has limited capacity partly due to its voluntary nature and infancy. It needs institutional support to grow and be useful for members. Department of Agriculture extension officers knew little about organic farming, thus limiting their engagement and assistance to such farmers. The theme of ‘market and logistics’ looked at the various factors that influence the farmers’ market reach. The perception from the members was that there was minimal consumer awareness about organic agriculture and the PGS. The marketing of organic produce relied largely on the individual farmer’s efforts and ability to search for and secure markets. The theme of the ‘learning process’ was categorised into learning and knowledge exchange. Members of the PGS groups highly regarded the invaluable knowledge shared through farm visits and online platforms, such as their WhatsApp groups. This knowledge improved and informed their farming techniques and led to the growth of v their skill base and experimentation. They viewed the way knowledge was exchanged as non-threatening and highly useful. The fourth theme of ‘disturbance, shock and stress’ dealt with the effects of COVID19. The three groups were all affected by lockdown restrictions (at the time of data collection) and were initially cut off from their usual markets. This led to a loss of income, loss of farm staff and a loss of the desired growth of the farms. The group’s diverse farming practices bolstered their resilience, enabling them to adapt and try alternative marketing strategies. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2023
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  • Date Issued: 2023-04

Challenges and opportunities of coastal and marine tourism in Swartkops river Estuary

  • Authors: Nokela,Thembela
  • Date: 2023-04
  • Subjects: Marine -- South Africa -- Swartkops River Estuary , Nelson Mandela Bay Municipality—Tourism , Estuarine pollution
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/61316 , vital:70083
  • Description: This study's goal was to pinpoint the challenges and untapped opportunities associated with Coastal and Marine Tourism (CMT) in the Swartkops River Estuary (SRE). CMT has become the biggest segment of the travel industry. Moreover, this form of alternative tourism is the most significant and fastest developing economic activity in the ocean. The objectives of this study were to identify the challenges that hinder the development of CMT in SRE, to determine opportunities for CMT in SRE, to evaluate NMBM’s efforts in creating and sustaining CMT in SRE and to evaluate the status of CMT in SRE in terms of CMT related development. This study fit within the interprevist paradigm and made use of a qualitative research approach and design as well as inductive reasoning. The qualitative research design consisted of data being collected through document and content analysis. Data was analysed using data analysis process of Miles and Herman (1994) as well as the coding and developing of specific themes that emerged from the data. The data in this phase was presented both in narrative format and tables. The document analysis used in this study was established based on the objectives of this study. The findings of this study revealed that key challenges that hinder the growth of CMT in Swartkops River Estuary are environmental impacts that include pollution, over enrichment, inappropriate development, overfishing, destruction of mudflats, limited freshwater inflow, destruction of vegetation and climate change. The findings also revealed that there are opportunities for CMT in SRE such as promoting SRE as a popular ecotourism destination by developing ecotourism nodes. These include environmental education at the Aloes Nature Reserve's and the Swartkops Estuary south-east section, sustainable ecolodges and conference centres. The study recommends that the Nelson Mandela Bay Municipality should organize educational programmes to educate local people about the significance of conserving and safeguarding the environment for future generations. These findings also posed certain challenges linked to those identified in the analysis. , Thesis (MPhil) -- Faculty of Business and Economic Sciences, School of Economics, Development & Tourism, 2023
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  • Date Issued: 2023-04

Challenges and opportunities of coastal and marine tourism in Swartkops river estuary

  • Authors: Nokela, Thembela
  • Date: 2023-04
  • Subjects: Marine Protected Area , Ocean economy
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/62286 , vital:72370
  • Description: This study's goal was to pinpoint the challenges and untapped opportunities associated with Coastal and Marine Tourism (CMT) in the Swartkops River Estuary (SRE). CMT has become the biggest segment of the travel industry. Moreover, this form of alternative tourism is the most significant and fastest developing economic activity in the ocean. The objectives of this study were to identify the challenges that hinder the development of CMT in SRE, to determine opportunities for CMT in SRE, to evaluate NMBM’s efforts in creating and sustaining CMT in SRE and to evaluate the status of CMT in SRE in terms of CMT related development. This study fit within the interprevist paradigm and made use of a qualitative research approach and design as well as inductive reasoning. The qualitative research design consisted of data being collected through document and content analysis. Data was analysed using data analysis process of Miles and Herman (1994) as well as the coding and developing of specific themes that emerged from the data. The data in this phase was presented both in narrative format and tables. The document analysis used in this study was established based on the objectives of this study. The findings of this study revealed that key challenges that hinder the growth of CMT in Swartkops River Estuary are environmental impacts that include pollution, over-enrichment, inappropriate development, overfishing, destruction of mudflats, limited freshwater inflow, destruction of vegetation and climate change. The findings also revealed that there are opportunities for CMT in SRE such as promoting SRE as a popular ecotourism destination by developing ecotourism nodes. These include environmental education at the Aloes Nature Reserve's and the Swartkops Estuary south-east section, sustainable ecolodges and conference centres. The study recommends that the Nelson Mandela Bay Municipality should organize educational xv programmes to educate local people about the significance of conserving and safeguarding the environment for future generations. These findings also posed certain challenges linked to those identified in the analysis. It is recommended that local communities are urged to take an active role in CMT and should regard CMT as a vital development sector that produces jobs. The study also recommends that the community can also develop local campaigns such clean ups, challenging the efficiency of environmental policies and participating dialogues to help alleviate the environmental impacts faced by SRE , Thesis (Ma) -- Faculty of Faculty of Business and Economic Sciences, 2023
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  • Date Issued: 2023-04

Community participation in selected public schools of Komani, Eastern Cape

  • Authors: Sondlo, Oyisa
  • Date: 2023-04
  • Subjects: Community participation , Common schools , Chris Hani District, Eastern Cape
  • Language: English
  • Type: Master's theses , Thesis
  • Identifier: http://hdl.handle.net/10948/61578 , vital:71379
  • Description: This study is located in Mlungisi Township of Komani in the Eastern Cape - where the aim was to closely examine the role played by this community to build and govern its public schools. The study selected the three biggest schools in the area to examine how the community’s involvement in them has surfaced from their founding up to the present times. The study found that through these three schools, this community managed, under apartheid, to take initiative by mobilising itself for self-development by building these schools and infusing them with a liberation curriculum that was required for the conditions of oppression and resistance at the time. This community in essence turned the intentions of Bantu education around by using these schools as sites of alternative education that was delivered by its own activist teachers to conscientise the student youth about community struggles. Black people in this community used these schools as emancipatory spaces to connect student struggles with community struggles to build community power. In the post-apartheid epoch, much of these traditions and levels of community participation have dropped because of new precarious economies and labour conditions that keep the adult population busy. As a result, present-day community participation is not as politically intentional as it was under apartheid. Theoretically, the study applied Paulo Freire’s Critical Community Pedagogy. Methodologically, the study utilised critical qualitative oral histories and semi-structured interviews. , Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2023
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  • Date Issued: 2023-04

Distinguishing elephant induced thicket degradation and climate related factors in Addo Elephant National Park, Eastern Cape, South Africa

  • Authors: Mapheto, Tlhologelo James
  • Date: 2023-04
  • Subjects: Elephant – Behaviour -- South Africa -- Addo Elephant National Park , Wildlife conservation -- South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/60753 , vital:66741
  • Description: The Addo Elephant National Park (AENP) is an ecologically sensitive environment where the increase in elephant population, especially in a changing climate is a recipe for landscape degradation and biodiversity loss. The Park is situated in the drought prone Eastern Cape Province, however, the effects of drought on thicket vegetation is less understood. This study aimed to distinguish elephant-induced thicket degradation from the effects of climatic factors, using remote sensing, GIS, and statistical techniques. To characterise and map vegetation conditions of the reserve temporal series Landsat imagery (n = 22) from 1998 to 2018 were analysed. Vegetation states were determined using Normalised Difference Vegetation Index (NDVI) derived from the growing season of the study period. Using supervised per-pixel image classification technique, the NDVI values characterized into distinct land cover classes viz (1) Intact Thicket, (2) Transformed Thicket, (3) Degraded Thicket, (4) Bare Ground and (6) Water Bodies. Post-classification change detection and landscape fragmentation analysis was performed. Climatic data were obtained from existing weather stations and raster surface of accumulated rainfall and mean maximum temperature were developed using the Inverse Distance Weighting (IDW). Time series analysis was implemented on the NDVI and climatic condition data by plotting annual measures to indicate variable trends. Temporal trend analysis was performed on the NDVI data using the nonparametric Mann-Kendall trend analysis test to indicate thicket vegetation condition improvement and general degradation. The Residual Trend (RESTREND) approach was employed to remove the effect of rainfall on vegetation productivity. This involved using the Ordinary Least Square regression functionality in ArcMap to compute the relationship between ∑NDVI and accumulated rainfall for every pixel for the study period. The products of the regression were assessed using Pearson’s Correlation (r) at a significance level of 90% (p-value ≤ 0.1) to distinguish strong relationships. Overlay analysis was performed, using the NDVI trend slope and the correlation coefficient (r) raster surfaces, to model vegetation dynamics influenced by elephant activities. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
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  • Date Issued: 2023-04

Enhanced peoples housing process and income generation: a case study of the Vulindlela self-help housing programme in Kwazulu-Natal, South Africa

  • Authors: Mosiea, Tshepang Handsome
  • Date: 2023-04
  • Subjects: House of the People , Revenue-generating , Housing programme -- KwaZulu-Natal (South Africa)
  • Language: English
  • Type: Doctoral's theses , Thesis
  • Identifier: http://hdl.handle.net/10948/66206 , vital:74432
  • Description: The study presented in this thesis examines the effects of the Vulindlela self-help housing programme’s governmentality on income-generating opportunities by beneficiaries; the rationale and assumptions underpinning the self-help housing programme; and evaluates whether the programme was implemented according to policy. The study also investigates the relationship between the Vulindlela self-help housing programme’s beneficiary involvement, beneficiary satisfaction, and skills development provided by the programme on income opportunities for beneficiaries. Using the empirical case study of the Vulindlela self-help housing programme in KwaZulu-Natal, South Africa, this study verifies the EPHP’s view that self-help housing programmes provide fertile ground for livelihoods, income generation and asset ownership. The study is underpinned by the interpretivist paradigm, which relies on qualitative and quantitative data, comprising primary data (individual key-informant interviews and survey data); as well as secondary qualitative data from desktop research. It utilises a Foucauldian approach, in which the rationalities and practices of the self-help housing programme, and the effects of the technologies of self, power, self-esteem, self-responsibilisation and the market, are evaluated to see how these factors have influenced income generation by beneficiaries in one of the largest self-help housing policy programmes in SA. These technologies are examined in the context of the Vulindlela programme using Foucault’s theory of governmentality. The findings confirm that the Vulindlela programme was implemented according to its policy. However, not all aspects of the policy programme were understood or may have been implemented during the programme. As such, not all participants (i.e. housing beneficiaries, government officials and cooperative directors) understood the intended outcomes nor how these policy outcomes would be realised. Despite many challenges that confronted the implementation of the Vulindlela self-help housing programme, the study concludes that the governmentality of the Vulindlela self-help housing programme had a positive impact on income opportunities for beneficiaries. The programme is one that finds itself held between two contradicting rationalities: neoliberal aspirations (provision of market and income opportunities for cooperatives that vii act as contractors), and moral aspirations (initiating empowerment of disadvantaged beneficiaries/ community development). The rationale behind the Vulindlela self-help housing programme was about providing income opportunities for beneficiaries and was heavily influenced by the neoliberal ideas of the UN-Habitat and the World Bank. Key policy recommendations, informed by implementation challenges of the Vulindlela programme, are offered for policy adjustments, as well as a conceptual framework for the design and implementation of self-help housing programmes to realise intended policy outcomes, that is income generation by housing beneficiaries and enhancement of local economic opportunities through the programme. , Thesis (PhD) -- Faculty of Engineering Built Environment and Technology, School of Built Environment and Civil Engineering, 2023
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  • Date Issued: 2023-04

Evaluating provisioning and cultural ecosystem services in two contracting estuaries in Gqeberha, Eastern Cape

  • Authors: Booi Siphesihle
  • Date: 2023-04
  • Subjects: estuaries -- Gqeberha , ecosystem services , Economic value added
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/60982 , vital:69585
  • Description: Estuaries are notable for their biodiversity, productive and invertible fisheries, and significant capacities. This study assesses the economic value of the Swartkops and Sundays estuaries in Algoa Bay, Gqeberha, to estuary users and local communities1 . The data was collected from December 2021 to April 2022, during the summer and autumn seasons. The seasons are considered peak times; however, international travel was restricted during Covid-19 level one lockdown. The study employs both the Travel Cost method and the Choice experiment method. Based on the findings, anglers and bait collectors in Swartkops Estuary sell their catches for an average of R77.41. The majority of these anglers and bait collectors earn between R0 and R1 583 per month and rely on catch and bait for a living, with the majority of participants benefiting from provisioning ecosystem service. Sundays estuary users, on the other hand, primarily use the estuary for recreational purposes. Anglers visiting Swartkops and Sundays estuaries spend R4 709 128 and R2 203 158 annually on food and beverages, fuel/transport costs, bait. This contributes R7 534 572.67 and R3 525 052.18 to the local economy in Nelson Mandela Bay Municipality based on the multiplier. The study emphasizes the importance of estuary management and monitoring to preserve and protect them for future generations. The primary issue is to extract resources from the Swartkops and Sundays estuaries in a sustainable manner while also protecting them. Estuaries can help grow the economy if managed well and used in a sustainable way. , Thesis (MA) -- Faculty of Business and Economic Science, 2023
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  • Date Issued: 2023-04

Evaluation of the toxicity of secondary metabolites in Solanum incanum L. to advance community knowledge

  • Authors: Zivanayi, William
  • Date: 2023-04
  • Subjects: Solanum -- Zimbabwe , Pesticides -- Toxicology , Medicinal plants
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/61018 , vital:69686
  • Description: The effects of pests and the need to produce adequate food have influenced small-scale farmers in disadvantaged communities to adopt and utilise natural plant pesticides to improve harvests in many Southern African Development Communities. However, the phytochemistry associated with these indigenous plants’ pesticide activity still needs to be explored. The lack of evidence of scientific knowledge of the plant species has caused a lot of health issues among the users of indigenous plant pesticides. Solanum incanum is among the plants utilised to control cabbage aphids in Mkoba village, Zimbabwe. Solanum species are known for their steroidal compounds which comprise glycoalkaloids and saponins. This study evaluated the knowledge, opinions, and attitudes of the vegetable peasant farming community in Gweru regarding their use of the indigenous plant (S. incanum) as a pesticide. The study also reported the phytochemical profiling, structural characterisation of the isolated compounds, and biological and pesticidal activity evaluation of phytochemicals isolated from S. incanum. A descriptive survey was carried out to assess the knowledge, attitude, and practices of a conveniently sampled group of vegetable farmers in Mkoba village who use S. incanum as a pesticide. Forty-nine respondents comprised of 19 males and 30 females of ages ranging from 15 to above 60 years took part in the study by answering an open and closed-ended questionnaire. The survey revealed that parents and neighbours were instrumental in disseminating pesticidal information in the community. Brassica napus were the most grown.vegetable and vulnerable to cabbage aphids. Mixed opinions amongst the respondents varied regarding the health and environmental impact of S. incanum as a pesticide. Seventy-five percent (75%) of the respondents supported the use of S. incanum as a pesticide whilst 25% claimed that the use of S. incanum was the source of the health problems experienced in the community. The survey demonstrated that (45)91% of the farmers displayed poor practices regarding the disposal of empty pesticide containers and the use of personal protective clothing. The most prevalent symptoms in the community were skin rash, nausea, headache, and poor vision and these symptoms were common in the age group 30 to 60 years. , Thesis (PhD) -- Faculty of Science, School of biomolecular and Chemical Sciences, 2023
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  • Date Issued: 2023-04

Factors affecting pinniped skull morphology

  • Authors: Penaluna, Julia Elizabeth
  • Date: 2023-04
  • Subjects: hybridisation -- South Africa , Sexual dimorphism (Animals) , Craniology
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/61306 , vital:70077
  • Description: Morphologies have evolved due to trade-offs between competing selective pressures. This is especially true for the skull. Not only does it contain the brain and the organs that are responsible for sensory function, but it is also contains components that play important roles in feeding, breathing, balance, defence, aggression and communication. The pinnipeds, a group of species that has evolved from terrestrial origins and became adapted to the marine environment, are under numerous selective pressures within the marine environment. These species have had to evolve in order to capture and process food underwater, and to dive. In addition, they are also characterised by substantial sexual size dimorphism in some species. Pinnipeds also make use of numerous marine and haul-out habitats with varying characteristics and complexity. Hybridisation has been recorded among pinnipeds, resulting in the production of hybrid offspring with characteristics that are different to their parent species. The aim of the study was to investigate the effect of these life history characteristics on skull and mandible morphology of pinniped species using three dimensional geometric morphometrics. To achieve this, 43 skull and 15 mandible 3D landmarks were collected using a Microscribe G2X digitizer with 0.2mm accuracy, on the skull and mandibles of 17 species of pinnipeds across three families, and one hybrid species. In total, 96 specimens across these species were examined. Data on the different life history characteristics of each species were collected from the literature. These data were plotted onto the PCA results in order to create and visually compare minimum convex polygons for each life history category. The results found that phylogeny, feeding strategy and sexual dimorphism were the most important factors in explaining differences in pinniped skull and mandible shape and size. may have resulted in these changes. Similarly, the inclusion of more species, covering a broader range of life histories may be beneficial. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
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  • Date Issued: 2023-04

Inner-city regeneration in South Africa : a property development approach

  • Authors: Chidzambwa, Overt
  • Date: 2023-04
  • Subjects: Regeneration -- South Africa , Real estate development
  • Language: English
  • Type: Master's theses , Thesis
  • Identifier: http://hdl.handle.net/10948/60578 , vital:65894
  • Description: Worldwide, the topic of inner-city decay and regeneration continues to attract a lot of attention from various parties and organisations. This is largely due to the fact that Central Business Districts (CBDs) remain the heartbeat of any city’s economic, social and political vibrancy. It therefore remains an ongoing process for the government and private stakeholders to keep on devising strategies aimed at revitalising the inner-city. The problem of urban decay is however experienced more in the developing third world and is characterised by high unemployment rates, high crime rates, depopulation, desolate-looking landscapes, abandonment of buildings, split families amongst others. Urban decay does not have one single cause, but rather a combination of many, including poor urban planning, redlining, poverty, suburbanization, and racial discrimination. These factors have resulted in urban sprawl as property owners preferred to migrate from the increasingly toxic social and economic environment that now became of the inner-city. The study seeks to investigate the current state of urban decay in South African CBDs with a case study of Gqeberha metro city, it also investigates current efforts and measures in place for regeneration and lastly, recommendations that have been put and continue to be put in place for inner-city regeneration. The state of inner-city infrastructure, property development finance options, town planning requirements and regulations and the investment case are other factors that have been investigated. Various other aspects of inner-city dynamics in the context of property development have been explored with findings from extensive literature review and structured interviews enabling the researcher to come up with recommendations for sustainable inner-city regeneration. , Thesis (MSBE) --Faculty of Engineering Built Environment and Information Technology, School of Built Environment and Civil Engineering, 2023
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  • Date Issued: 2023-04

Investigating thermoregulatory responses of rhabdomys pumilio at high wet-bulb temperatures

  • Authors: Hartley, Oliver
  • Date: 2023-04
  • Subjects: Heat stress physiology , Small mammal thermoregulation -- South Africa , Climate change - Wet-bulb temperature
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/60873 , vital:68916
  • Description: As the Anthropocene continues to be characterised by ever rising temperature highs, increasingly sporadic and extreme climatic events, and their accompanying mass mortality events, climate scientists now warn that the continued climate destabilisation may for the first time in recorded history prevent terrestrial homeothermic endotherms from being able to thermoregulate. Having evolved to maintain body temperatures (Tbs) well above their ambient (Ta) conditions, these endotherms have evolved a suite of adaptations to a colder environment to allow for homeothermic thermoregulation to occur. However, by the same vein, having evolved in a colder climate to stay warm also has led to a reduced capacity to prevent heat stress when temperature conditions are elevated. In absence of behavioural counter measures, the only physiological means available to thermoregulation to prevent such heat stress is that of evaporative water loss (EWL). If still inefficient, the endotherm will risk becoming hyperthermic. Literature has established that excessive heat exposure or reduced evaporative cooling capacities strain or retard thermoregulatory processes. If an endotherm experiences severe heat exposure, the rate at which passive heating is experienced will increase. Should an endotherm be in a humid environment, evaporative cooling efficiency is reduced. As a result, these two abiotic factors are therefore known to contribute towards heat storage, and therefore thermal stress. However, should both factors occur in the same environment, the heat stress effects are compounded, creating an environment dangerous for thermoregulating endotherms. For this reason, authors have emphasised that future wet-bulb (Tw) conditions may pose a penultimate threat to thermoregulating endotherms. Being a measure of coldest temperature attainable as a result of evaporative cooling, Tw has been proposed to represent a lower temperature thermal limit to endothermic thermoregulation. Once reaching a 2°C differential below an endotherms Tb (Tb – Tw = 2˚C), Tw is believed to impede the evaporative cooling process and, consequentially, commit endotherms to becoming hyperthermic. Considering that most mammals defend constant Tbs within the range of predicted Tw maxima increases that future Tw conditions may pose a significant threat to mammalian thermoregulation. However, to date, despite being well supported in the literature, ii empirical investigations into how extreme Tw conditions will affect endothermic thermoregulation are scant. Therefore, understanding of the proposed inhibitory nature of extreme Tw conditions is lacking. Considering that such conditions are to have a profound effect of endothermic survival, this dearth in understanding could prove fatal. As such, this thesis sought to provide evidence on how extreme Tw conditions may affect thermoregulatory processes in homeothermic endotherms. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
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  • Date Issued: 2023-04

Parental influence on next-generation family members in South African black-owned family businesses

  • Authors: Ntari, Lwando
  • Date: 2023-04
  • Subjects: Business enterprises, Black , Family-owned business enterprises
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/62299 , vital:72376
  • Description: This study focuses on the parental influence on next-generation family members in South African Black-owned family businesses. In both developed and developing countries, the majority of businesses are family-owned and contribute significantly to their country's economic growth. To be sustainable, family businesses should anticipate, recognise and understand the impact parents have on their next-generation family members’ intentions to join the family business. Controlling a family business with the intent to transfer it to the next family generation is often seen as the defining characteristic of family businesses. Transferring the control of a family business to the next generation presents a critical managerial challenge. It has been noted that parents are the most important influence in a child’s life and could therefore have the greatest influence on their career choice. This study discusses parents' impact on their next-generation family members’ career choices in the context of career choice theories: Holland’s theory of vocational personalities in the work environment, Super’s developmental self-concept theory, and social cognitive career theory. Moreover, the important influence that parents have on their children and the impact of the parent is elaborated on; the characteristics of the parent's job, self-efficacy, outcome expectations, parent's relationship, parental expectations, parent's style, and cultural influence are discussed. In addition, career choice theories in the South African context are also briefly discussed. The lack of desire of next-generation family members to join the family business endangers its long-term sustainability. Although numerous factors influence a person's career choice, including the decision to join their family business, parents are by far the most influential. Therefore, the primary objective of this study was to identify the influence parents have on a next-generation family member’s intention to join the family business. A structured questionnaire was distributed to South African respondents with parents who own a family business. Respondents were identified by means of judgemental sampling. A total of 317 usable questionnaires were subjected to statistical analysis. The validity of the scales measuring the dependent and independent variables was assessed using factor analysis, and the scales’ reliability was confirmed by calculating Cronbach’s alpha coefficients. Both descriptive and inferential statistics were calculated. The family businesses iv associated with the respondents were mostly first-generation owned. The majority of respondents were Xhosa and Zulu speakers and represented family businesses that employed more than five employees. The next-generation family members who participated in this study were predominantly males under the age of 25 years, and most had no post-matric qualification. Multiple regression analysis was used to assess the hypothesised relationships. The results indicate that four parental influences (parental style, culture, self-efficacy and parental identification) significantly influence a next-generation family member’s intention to join the family business. It is important for parents to understand which factors influence their children's decision to join the family business, as this allows the parents to manage these factors best. , Thesis (Ma) -- Faculty of Faculty of Business and Economic Sciences, 2023
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  • Date Issued: 2023-04

Perceptions of mental illness among the residents of the Eastern Cape Province in South Africa: The influence of culture and religion on their coping strategies.: subtitle if needed. If no subtitle follow instructions in manual

  • Authors: Sikrweqe, Odwa
  • Date: 2023-04
  • Subjects: Mental illness , Mental illness--Religious aspects , Mental illness-- Culture aspects
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/60445 , vital:65507
  • Description: Mental illness has become a global concern, with consequences that may result in a mental health pandemic. Studies conducted on mental illness suggest that religious and cultural beliefs not only affect the expression of mental illness, but also the diagnosis and treatment of mental conditions. South Africa is a country imbued with cultural and religious diversity, which creates different groupings of people, holding diverse beliefs regarding mental illness. In many contexts, supernatural beliefs, traditional healing and indigenous medicines and treatments are considered in the treatment of the symptoms associated with mental illnesses, especially on contexts where there is a reliance on religio-cultural beliefs. Even though there has been a significant increase in the contribution to research focusing on mental health in diverse contexts, much of this research has focused on subjective experiences. Little to no information is available on population-based studies in South Africa regarding mental illness in diverse contexts, thus limiting the generalisation of findings related to cultural and religious influences on mental illness. This dearth of information further limits the development of psychological interventions. The study aimed to explore how mental illness is perceived by the participants and thereafter explored the influence of culture and religion in coping with mental illness by the residents of the Eastern Cape. The study was quantitative in nature and adopted an exploratory-descriptive design. The researcher made use of a questionnaire as a research tool and QuestionPro was utilized as a platform. A convenience sampling technique was utilised. In ensuring rigour of the study, the researcher ensured maximal validity (accurate representation of the data) and reliability (ability to repeat the research procedure). Ethical principles have been adhered to as per the principles on the Belmont Report, to ensure safety of the participants and this includes anonymity, confidentiality and the right to withdraw from participation in the study. Data has been analysed using descriptive and inferential statistics. A sample size of 101 participants from the general population of residents of the Eastern Cape completed the online survey. The results of the study revealed that the residents of the Eastern Cape have substantial knowledge pertaining the cause of mental illness and indicated both positive and negative attitudes towards the mentally ill and possess coping strategies to deal with a mental illness. In addition, the results show that there is a relation between religion/culture and coping with a mental illness by the participants of the study. The findings of this study emphasize the necessity of public education efforts that understand and respect people's cultural diversity, as well as teamwork among traditional and medical professionals. Future studies should focus on the use of discourse analysis to better investigate indigenous groups' conceptions of mental illness and their views about its aetiology and treatment. , Thesis (MA) -- Faculty of Health Sciences, School of Behavioural Science, 2023
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  • Date Issued: 2023-04

Pleistocene vertebrate trace fossils from the Cape south coast of South Africa: inferences and implications

  • Authors: Helm, Charles William
  • Date: 2023-04
  • Subjects: Geology, Stratigraphic -- Pleistocene , Vertebrates, Fossil -- South Africa , Paleontology -- Pleistocene
  • Language: English
  • Type: Doctor's theses , text
  • Identifier: http://hdl.handle.net/10948/60589 , vital:65942
  • Description: Palaeoichnology, the study of fossil tracks and traces, has had a relatively late start on the Cape south coast of South Africa. Since its inception in 2007 the Cape south coast ichnology project has led to the identification of 326 Pleistocene vertebrate ichnosites in aeolianites (cemented dunes) and cemented foreshore deposits between the community of Arniston in the west and the Robberg Peninsula in the east, a distance of approximately 350 kilometres. As a result, significant palaeoevironmental, palaeocological and palaeoanthropological inferences have been made. This thesis brings together this corpus of work, and attempts to answer the question of how ichnology can inform the understanding of the Cape south coast Pleistocene environment, and how the trace fossil record can complement the body fossil record. Achieving this objective involves the development of a definitive regional account. This includes descriptions of the regional geological context, Quaternary sea-level changes, and the state of knowledge of the region’s Pleistocene palaeoenvironment, palaeoanthropology, and body fossil record, along with an understanding of the roles of substrate and taphonomy in regional ichnology. A discussion of geochronology includes the age results from specimens submitted for dating through optically stimulated luminescence – dated deposits range in age from Marine Isotope Stage 11 through Marine Isotope Srage 3. The body of the thesis is formed by systematic descriptions of the vertebrate ichnosites, accompanied by interpretation and comments. Three databases have been compiled: ichnosites, photographs, and photogrammetry images. In synthesizing this data, four underlying questions are addressed: what is the global relevance of the Cape south coast ichnosites, how can these studies complement the vertebrate body fossil record, how can they contribute to the understanding of Pleistocene palaeoenvironments and palaeocology, and how can they contribute to palaeoanthropology? The Cape south coast is of global ichnological importance. Unanticipated findings which augment the sparse reptilian body fossil record include tracks and traces of crocodiles, monitor lizards, very large tortoises (the first of their kind in the global record), and hatchling sea turtles. Two new ichnogenera have been erected to describe the sea turtle tracks, each containing a new ichnospecies: ustralochelichnus agulhasii and Marinerichnus latus. Avian ichnosites are the oldest in southern v Africa, and include the presence of tracks of larger-than-expected birds, which may represent large chronosubspecies or may suggest the possibility of extinctions which are not evident from the body fossil record. Unique examples of the non-hominin mammalian ichnosites include sand-swimming traces that resemble those of the ‘Namib mole’: as a result a new ichnogenus (Natatorichnus) has been erected, containing two ichnospecies, N. subarenosa and N. sulcatus. The first elephant trunk-drag impressions and the first pinniped ichnosites in the global record have been identified. The role of elephant tracks as precursors to coastal potholes was previously unsuspected. Equid tracksites indicate a widespread presence of the extinct giant Cape horse (Equus capensis). The identification of a giraffe tracksite represents a major range extension. In particular, tracks and traces of giraffe, crocodiles, breeding sea turtles, and sand-swimming golden moles have significant palaeoenvironmental implications. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
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  • Date Issued: 2023-04

The Living Archive as Pedagogy: A Conceptual Case Study of Northern Uganda

  • Authors: Munene, Anne Wambui
  • Date: 2023-04
  • Subjects: Archives , Education -- Study and teaching , Case Study -- Northern Uganda
  • Language: English
  • Type: Doctoral's theses , Thesis
  • Identifier: http://hdl.handle.net/10948/60927 , vital:69226
  • Description: The Living Archive as Pedagogy emerges from Northern Uganda’s experience of war 1986- 2008, between the Lord’s Resistance Army and the Uganda People’s Defense Force previously named the National Resistance Army. This period of war and post-war has been a difficult experience where finding solutions and mechanisms for transition or justice remain complex, restricted, delayed and consequently concealing the reality of lived marginalization from below. The Acholi of Northern Uganda went through predatory atrocities, painful humiliation and unwilled cohabitations with their oppressors during war and post-war. The study explores how the interlinking of archives and pedagogy as independent disciplines can extend possibilities for more transformative education horizons in bottom-up, post-conflict expressions. The study is immersed through a conceptual and theoretical framing in the boundaries of archiving and pedagogy, to understand how the war constructs Acholi’s lived experience in multiple complex ways. While the Acholi re-orient their lives post- war, we recognize their attention in affirming their human agency, ordering of new and different meanings, desiring a different liberation in post-conflict where responsibility in contexts of “up againstness” validates their dwelling and being in spaces that exclude them. The research acknowledges that pedagogy and archiving studies in post-conflict, needs restructuring to challenge the preserving of external and dominant epistemological purviews that order post-conflict reconstruction life. These traditions exclude the experiences of survivor-victims, are tone deaf to community-based groups articulations of post-conflict repair, and neither does lived experiences of the everyday gets organized as an outcome for knowledge. This is discussed at length, as the research responds to its central question of how living archive as pedagogy can offer a transformative education discourse. The conclusion of the study emphasizes self-representation through transformative knowledge positions of I am whom I am, Where I am, Where I Speak, and Where I think. These positions articulate a self-understanding that supports rehistrocizing of post-conflict society as a body resisting exclusion in dominant knowledge formation and institutional omissions. There is evidence of the research foregrounding the formation of person-hood from experiences of ‘up againstness” and knowledge/under-stand[ing] from below. The research facilitates a hermeneutical encounter with specific inscribed bodies of post-conflict experience, the Acholi and Wanjiku whose bodies archive a horizon of possibilities if a different and difficult reading vii of the world is done from locations of struggle to produce consciousness of re-becoming, or returning to the human. These pedagogical experience positions Acholi and Wanjiku as educators, and their lives a living archive. We the readers are invited to a learning process as willing ‘hearers’ of Acholi and Wanjiku testimony, to own responsibility as our practice to ensure they appear in the world to say their truth, as they defy conditions of their oppression. , Thesis (PhD) -- Faculty of Education, School of Education Research and Engagement, 2023
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  • Date Issued: 2023-04

The moderating influence of socioemotional wealth on the innovation choices and outputs of South African family businesses

  • Authors: Ndang, Akah William
  • Date: 2023-04
  • Subjects: Socioemotional wealth, , Family-owned business enterprises
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/62216 , vital:72012
  • Description: The global impact of family businesses is increasing in a significant manner. The importance of family businesses has been recognised by academic institutions through the establishment of family business research centres and academic programmes for family businesses, as well as practitioner-oriented journals in family business studies. In most developed and developing market economies, family businesses have been projected as one of the primary forms of private enterprise that play an important role in both national and global economies, including South Africa. In other words, in the global innovation context, family businesses are considered to be the backbone of economic development. Given the importance of innovation to family businesses in contributing to economic growth and sustainability across generations, as well as the limited research that has been conducted on South African family businesses and innovation, the primary objective of this research was to investigate the relationship of selected drivers of innovation and Innovation outputs in South-African family businesses, as well as how the family, through its Socioemotional wealth, moderates the relationships between the drivers of innovation and Innovation outputs. This study uses the socioemotional wealth (SEW) and the resource-based theory (RBV) as the basis of its theoretical orientation. The following drivers of innovation were identified during the literature review (independent variable), namely: Financial capital, Human capital and leadership, Social capital, Learning orientation, Entrepreneurial orientation, Market orientation, Organisational culture, and Knowledge management as having an impact on Innovation outputs (dependent variable). In addition, Socioemotional wealth (SEW) was hypothesised as having a moderating influence on the relationships between the drivers of innovation and Innovation ouptuts. Four demographic variables (Size of the business, Age of the business, Generation of the family and Industry of operation) were identified as having a potential influence on the hypothesised relationships. Each of the constructs were clearly defined and then operationalised. Operationalisation was done by using reliable and valid items sourced from tested vii measuring instruments used in previous studies, as well as a number of self-generated items based on secondary sources. A structured questionnaire was made available online to respondents identified by means of the convenience snowball sampling technique, and data was collected from 331 family businesses in South Africa. The usable questionnaires were subjected to various data analyses techniques. Confirmatory Factor Analyses (CFA) were performed on each factor that confirms the factor structures by using various goodness-of-fit indices. Subsequent to the CFAs, the validity and reliability of the measuring instrument was assessed. As a result of these analyses, three new independent variables emerged as drivers of Innovation outputs in South African family businesses, namely: Funding of research and innovation, Financial, human and social capital resources, and Shared business vision, resources information and knowledge. In addition the SEW construct revealed two dimensions as dependant variables, namely: Family influence, control and commitment and Business reputation and commitment. The reliability of the measuring instrument was evaluated using Cronbach’s alpha coefficients, while the assessment of validity involved calculations of the average variance extracted (AVE) estimates and squared correlations between constructs. Structural Equation Modelling (SEM) was the main statistical procedure used to test the significance of the relationships hypothesised between the various independent, moderating and dependent variables. The main finding of the study reveals that there is a significant positive relationship between Financial, human and social capital resources, and Innovation outputs. There is also a significant positive relationship between Shared business vision, resources, information and knowledge and Innovation outputs. Furthermore, Family influence, control and commitment positively moderates the relationship between Shared business vision, resources, information and knowledge and Innovation outputs. while Business reputation and succession positively moderates the relationship between Financial, human, social capital resources, and Innovation outputs. Finally, Business reputation and succession positively moderates the relationship between Shared business vision, resources, information and knowledge viii and Innovation outputs. Concerning the selected demographic variables, this study found that Age of the business has a significant influence on Innovation outputs. This study makes several theoretical and practical contributions. This study is the first of its kind that investigates the relationship between the drivers of innovation and Innovation outputs of South African family businesses. Second, this study is the first to investigate how the family, through its Socioemotional wealth, moderates the relationships between the drivers of innovation and Innovation outputs of South African family businesses. Having a better understanding of how and when the family system impacts the innovation decisions in the family business is important because it helps researchers understand the differences between family businesses (i.e. family firm heterogeneity) and non-family businesses. Third, the findings indicated that the adaptation of the SEW and RBV theories was accurate in understanding how the family, through its socioemotional wealth, influences innovation decisions. Fourth, concerning the selected demographic variables, this study found that Age of the business has a significant influence on Innovation outputs. This finding is another valuable contribution to the literature on innovation, given the inconsistent and sometimes inconclusive findings concerning the relationship between age of the business and innovation activities. The study's final theoretical contribution is the development of a measurement tool that accurately assesses the drivers of innovation and innovation outputs and the influence of the five dimensions of socioemotional wealth. Other family business researchers, business mentors and or family business owners themselves can use this measurement tool to assess and monitor factors that have an impact on innovation activities inside their businesses. Practically, this study makes several suggestions on how family business owners and managers could improve the Innovation outputs of their businesses and become aware of how the family could influence the innovation choices and decisions made in the business. , Thesis (PhD) -- Faculty of Faculty of Business and Economic Sciences, 2023
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  • Date Issued: 2023-04

Viability of government funded broiler production : lessons from Northern KwaZulu Natal, South Africa

  • Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
  • Date: 2023-04
  • Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10353/27843 , vital:69947
  • Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
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  • Date Issued: 2023-04

A native weevil and an exotic planthopper: investigating potential biological control agents for nymphaea mexicana zuccarini (nymphaeaceae) and its hybrids in South Africa

  • Authors: Reid, Megan Kim
  • Date: 2023-03-31
  • Subjects: Nymphaeaceae South Africa , Water lilies Biological control South Africa , Host specificity , Genetic variation , Bagous longulus
  • Language: English
  • Type: Academic theses , Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/422554 , vital:71957 , DOI 10.21504/10962/422554
  • Description: Nymphaea mexicana Zuccarini (Nymphaeaceae) is an invasive plant originating from southern USA and Mexico that has become problematic in South Africa, invading several water bodies around the country. Manual removal of this plant is very labour intensive and is not cost efficient or effective for long term control, while the use of herbicides is damaging to the environment and expensive. Consequently, this plant is a desirable candidate for biological control, which takes advantage of enemy release of the target weed and aims to re-establish population suppression induced by host specific natural enemies. Initiating biological control requires that several steps are followed to maximise the success of the programme, and the first few of these, including overseas surveys in the native range of the plant, have already been completed. This thesis aimed to continue biological control research for this species to take further steps at effectively managing the plant. Firstly, pre-release surveys in the invaded range are necessary to: determine what factors (including enemy release) contribute to the invasiveness of the target weed; establish a baseline of information to allow for comparison after biological control agents have been released; and identify any insect herbivores that may already be present in the country. The pre-release surveys conducted in this study revealed useful information about N. mexicana invasions in South Africa and provided evidence that enemy release is applicable to this case. However, these studies determined that a native weevil, Bagous longulus Gyllenhal (Coleoptera: Curculionidae), has expanded its host range to include the exotic N. mexicana at three sites, and may thus have potential for management of the species through augmentative releases. The invasion of N. mexicana in South Africa is further complicated by the presence of several Nymphaea hybrids originating from a complex history of horticultural trade. Although previous research has shown that several hybrid groups are present in South Africa, their parentage is not known. As biological control requires the use of host specific insects adapted to overcome the unique chemical and morphological defences utilised by plant species, hybrids are notoriously difficult to manage because they possess intermediate characters inherited from parent species to which natural enemies may not have adapted. Although biological control of hybrids is challenging, other case studies have demonstrated that it is possible to find suitable agents, but the chances of success are increased if putative parents of the hybrids are known so that they can be surveyed for natural enemies. Further molecular studies including possible parents of the Nymphaea hybrids in South Africa were thus carried out in this thesis to focus future surveying efforts. Two main hybrid groups were identified with genetic similarity to two tested putative Nymphaea parents, and this will allow further investigations of these species to improve the chances of successfully managing these hybrid groups. Some of the tested hybrids showed genetic contributions from multiple groups, some of which were unidentified, so it is necessary to prioritise the most problematic hybrids for biological control. With more insight into the genetic makeup of the Nymphaea hybrids in South Africa, investigations into the host specificity of potential biological control agents can be conducted. The ideal biological control agent should have a broad enough host range to impact and survive on both N. mexicana and its hybrids, but without a host range so broad that it would pose risk to native South African species. Host specificity trials are thus necessary to determine the suitability of potential agents. The identification of B. longulus feeding on N. mexicana during pre-release surveys motivated further investigations to determine the natural distribution, field host range, and host specificity of B. longulus in experimentally controlled conditions. Further surveys were therefore conducted at native Nymphaea sites around South Africa in addition to host specificity trials using the native Nymphaea nouchali Burm. f. (Nymphaeaceae), two populations of N. mexicana, and a cultivated hybrid. Results from the surveys and host specificity tests suggest that B. longulus is widely distributed across South Africa, is specific to Nymphaea with no observed preference between N. mexicana and the native N. nouchali, and does not perform well on Nymphaea hybrids. Hence, B. longulus is promising for use in new association biological control through augmentative releases but is not suitable for management of hybrids. In addition to the potential use of the South African B. longulus, it is necessary to conduct host specificity trials for natural enemies from the native range of N. mexicana that were prioritised in previous studies. Megamelus toddi Beamer (Hemiptera: Delphacidae) is one such species that was imported into quarantined laboratory conditions from Florida, USA. Host specificity trials were conducted using the same test plants as described for the studies on B. longulus, in addition to multigeneration trials to determine how long M. toddi could survive on non-target host plants. As with the B. longulus studies, no statistically significant differences in preference were observed between N. mexicana and N. nouchali, but M. toddi could not complete development on the test hybrid, indicating that this species is also unsuitable for the management of Nymphaea hybrids. Despite suboptimal plant health, M. toddi completed development for three generations on the native N. nouchali. This lack of host specificity deems M. toddi unsafe for release in South Africa but highlights the importance of following predefined steps to develop a biological control programme. The concluding chapter of this thesis discusses the aforementioned findings in a broader context by considering the driving forces of plant invasions in general and specifically for N. mexicana in South Africa. Case studies are also consulted to provide insight into how to proceed with managing Nymphaea hybrids in South Africa, while the factors governing host specificity and host range expansion are also discussed and considered in the context of B. longulus and M. toddi. Finally, after a consideration of the limitations of these studies, recommendations are made to continue the development of biological control for N. mexicana in South Africa. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2023
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  • Date Issued: 2023-03-31

Innovation in ecological restoration techniques: Enhancing Portulacaria afra survivorship in degraded arid thicket

  • Authors: Norman, Yondela Masande
  • Date: 2023-03-31
  • Subjects: Uncatalogued
  • Language: English
  • Type: Academic theses , Master's theses , text
  • Identifier: http://hdl.handle.net/10962/419276 , vital:71630
  • Description: The Albany Thicket Biome has undergone extensive degradation over the past century, particularly from overstocking of livestock in the arid types of thicket. The degradation of the biome, coupled with little to no natural recovery, prompted the South African Government to implement the Subtropical Thicket Restoration Programme (STRP) in the early 2000s to rehabilitate degraded thicket using unrooted Portulacaria afra truncheons. The STRP also sought to create job opportunities, bring about social upliftment, promote biodiversity conservation and incentivise farmers and landowners in the region to promote carbon trading and farming of P. afra using carbon credits. However, the survivorship of P. afra planted using the STRP planting protocol has been less than ⁓30% because they are planted in degraded areas, where the truncheons are subjected to harsh biophysical conditions such as hard, capped soil, high soil temperatures, drought and herbivory. The aim of this study, therefore, was to improve the survivorship of P. afra planted in degraded thicket to at least 30%, using modified planting methods. In this study, four treatments were applied in 210 pondings (or micro-dams), each with P. afra planted in them (the first three treatments used rooted cuttings). The first treatment involved watering regimes where pondings were watered at varying frequencies. The second treatment involved planting companion species alongside P. afra while the third treatment involved planting P. afra underneath a nurse canopy. In the fourth treatment, unrooted P. afra truncheons were planted inside pondings. The mean survivorship of the P. afra cuttings was assessed 18 months after planting. The watering regime treatments, including the control, all yielded a survivorship of over 75%, with the significantly highest levels of survivorship being displayed in the weekly watering treatment (90.9 ± 6.8%) (p < 0.01). The companion plant treatment also produced a high mean survivorship of P. afra (94.9 ± 3.6%), significantly higher than that of the nurse plants (87.5 ± 6.3%) (p < 0.01). Among the unrooted truncheons it was found that untreated truncheons had the highest survivorship (76.2 ± 17.6%), with the lowest mean being found in truncheons that were both pruned and scarified (70.8 ± 20.8%), suggesting that this treatment, out of all of them, is the least successful under the prevailing environmental conditions in the study area. However, there was no significant differences among the unrooted truncheon treatments and their respective survivorship values to further substantiate this assertion (p = 0.26). Findings in this study also suggest that planting P. afra cuttings under a nurse plant was ideal for P. afra survivorship due to the nurse plant’s ability to ameliorate the microclimate under which the cuttings can establish and grow. Despite the soil under the nurse canopy having a significantly lower mean soil water potential (-160.9 ± 200.5 kPa), compared to the open areas (-73.4 ± 55.7 kPa) (p = 0.04), the pondings under the nurse canopy still had a lower mean soil temperature (31.4 ± 5.25°C) than the treatments in the open areas (38.5 ± 2.7°C), during the harsh midday sun. These favourable characteristics are reflected in the P. afra cuttings under a nurse canopy having a higher chlorophyll fluorescence (0.76 ± 0.06). compared to those planted in open areas (0.73 ± 0.13), suggesting that the P. afra cuttings in the former treatment had a higher photosynthetic efficiency compared to those in the latter, despite there being no statistically significant difference in chlorophyll fluorescence between the treatments (p = 0.14). Although these findings suggest that applying these modifications to planting P. afra, having achieved its objective of increasing survivorship to well over 50%, is likely to produce favourable results not only in overall survivorship, but also in fast-tracking arid thicket rehabilitation and restoration, further research on these rehabilitation techniques and their effectiveness is required. Furthermore, the downside to these treatments is that they are costly and time consuming, which puts the feasibility of large-scale programmes using these applications into question. Further investigation is required to determine ways in which the cost-effectiveness of these applications can be enhanced. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
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  • Date Issued: 2023-03-31
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