List of Titles

The enemy release hypothesis and beyond: Lagarosiphon major invasion dynamics and management options for New Zealand using native natural enemies from South Africa

- Baso, Nompumelelo Catherine

Authors: Baso, Nompumelelo Catherine
Date: 2024-04-05
Subjects: Enemy release hypothesis , Lagarosiphon major Biological control New Zealand , Hydrellia , Submerged aquatic vegetation , Invasion ecology
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/435627 , vital:73174 , DOI 10.21504/10962/435627
Description: Numerous scientific investigations have demonstrated the destructive impact that exotic species can have on ecosystem services beyond a specific threshold. There are many explanations for why introduced plants are likely to be more successful outside their native range. One such explanation is offered by the Enemy Release Hypothesis (ERH), which states that plants automatically become superior competitors outside of their natural range due to release from top-down stressors (herbivory, parasites, and diseases) that is evident in the absence of their natural enemies. The underlying assumption of the ERH is that natural enemies are important regulators of plant species populations, and that the pressures from these natural enemies are felt more readily by native species compared to alien plants. Consequently, in the absence of such pressures, the ERH assumes that exotic plants can allocate more resources towards growth and reproduction, while effectively maintaining accumulated biomass. Classical biological control has previously been cited as evidence for the enemy release hypothesis. Therefore, the overarching aim and theme of this thesis was to investigate the role of ERH on the invasiveness of Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae) in New Zealand. Firstly, a literature search and a meta-analysis was used to synthesize existing studies in order to test for general applicability of this hypothesis to aquatic plant invasions. Furthermore, an empirical investigation was conducted in order to directly quantify enemy release in L. major populations invaded areas of New Zealand. To achieve this, various plant parameters of this plant, overall macrophyte and invertebrate diversity were measured and compared between sites in the native range in South Africa and the invaded areas in New Zealand. Although the meta-analysis showed variable evidence for this hypothesis depending on various modulating factors such as study type, plant growth form and measured parameters, for L. major, there was strong evidence of enemy release. The biogeographical comparisons showed that L. major exhibited increased fitness in most of the invaded sites, marked by elevated biomass accumulation, significantly higher shoot production, and the displacement of native plant species. The observed fitness advantages were directly correlated to a decrease in herbivory diversity and pressure upon the plant's introduction to New Zealand. Unlike the native populations, which contend with the presence of at least four co-occurring herbivores, including specialist herbivores, the invaded range had a substantially lower herbivore diversity, with only Hygraula nitens Butler (Lepidoptera: Crambidae) syn. Nymphula nitens, significantly damaging L. major. These findings emphasize the importance of understanding invasion ecology and theories such as ERH in order to advance aquatic plant management and also present valuable insights for developing effective strategies to mitigate the impact of invasive alien species on aquatic ecosystems. Specifically, results from the empirical investigation provide evidence in support of the ERH and highlight the suitability of implementing biological control strategies to manage the L. major invasion in New Zealand. Previous studies have shown the suitability of two specialist herbivores, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), and Polypedilum tuburcinatum Andersen (Diptera: Chironomidae), as potential biological control agents. This control strategy presents a sustainable and ecologically responsible approach, promoting coexistence between exotic plants and native species rather than displacement through competitive exclusion. With the apparent dominance of L. major at various New Zealand localities, the subsequent objective of this thesis was to investigate the competitive interactions between L. major and another invasive Hydrocharitaceae, Egeria densa Planchon, as driven by herbivory. Combinations of two host specific Ephydrid flies, H. lagarosiphon and H. egeriae, were used at eight different factorial combination of planting densities. The analysis of plant parameters and the application of inverse linear models revealed that L. major often exhibits relatively higher fitness, especially in low monoculture treatments when the two insects were isolated. However, multiple inverse linear models revealed that actual competitive outcomes are dependent on factors such as initial plant density and herbivory regime, with competitive interactions generally being mild. Nevertheless, the presence of H. lagarosiphon resulted in facilitation of E. densa growth. Thus, even at lower densities, these insects still had an impact on the observed interactions, further emphasizing suitability as damaging biological control agents. Lastly, focusing on the abiotic component of L. major invasion, Species Distribution Models (SDMs) were employed to map potential suitable habitat for this species, as well as predict the consequences of climate change on this. Correlative and mechanistic modelling was also used to simulate suitable habitat for potential biological control agents, thus addressing the potential for mismatches between host plant distribution and insect suitable range. The Maximum Entropy Species Distribution Modelling (MaxEnt) algorithm revealed that more than 90% of all freshwater ecosystems in New Zealand are susceptible to L. major invasion, with suitability projected to expand further under future climate scenarios. Moreover, correlative modelling using this method suggests limited suitable habitat for both herbivores. However, degree-day modelling, which also takes into account the physiological requirements, showed that H. lagarosiphon has the potential to produce viable populations in several parts of New Zealand. Overall, this thesis explored the intricate web of biotic and abiotic factors influencing the success of L. major outside its native range. The results emphasize the potential impacts of climate change on the invasion potential and management strategies for L. major. The findings also advocate for the implementation of sustainable and ecologically sound management solutions, such as biological control, to manage this species. , Thesis (PhD) -- Faculty of Science, Botany, 2024
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Date Issued: 2024-04-05

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The impact of Malawi’s National Strategy on Inclusive Education: a case study analysis of two schools

- Kaunda, Bridget

Authors: Kaunda, Bridget
Date: 2024-04-05
Subjects: Inclusive education Malawi , Special education , Malawi. Ministry of Education , Resource programs (Education) , Education and state Malawi
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/436499 , vital:73277
Description: Using a qualitative case study approach, this study analysed the impact of Malawi’s National Strategy on Inclusive Education (NSIE) on inclusive education (IE) in two inclusive schools. IE is a global education reform for accommodating learners with Special Educational Needs (SEN) in mainstream schools. Malawi developed the NSIE in 2017 to guide IE implementation while working on the actual policy. This study aimed to analyse how NSIE has impacted IE during its first five years of implementation. This was done by examining how the NIES goals were designed, enacted, and implemented, the perceptions of system users, who include teachers, learners, and parents towards IE, and the enabling and constraining factors on its implementation. Drawing on the theoretical perspectives of the democratic theory of education and systems theory, this study argues that NSIE has ameliorated IE implementation by putting in place a structural implementation system. However, the implementation is marred by several constraining factors both at the management and implementation (schools) levels. Secondly, there is a disjuncture between NSIE as intended and as implemented in the sampled schools. Thirdly, the IE system lacks effective communication and responsive decision-making, especially in the monitoring process and school involvement. Fourthly, the study shows that IE implementation depends on a functional and well-stocked resource centre (RC) and the availability of enough qualified staff. It was also observed that poor teacher motivation resulting from lack of incentives such as promotions and training were major obstacles to the successful implementation of IE at the school level. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
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Date Issued: 2024-04-05

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The impacts of bottom-up and top-down drivers in shaping the herbivore community in Pafuri, Kruger National Park, South Africa

- Walker, Gareth Alexander

Authors: Walker, Gareth Alexander
Date: 2024-04-05
Subjects: Herbivores South Africa Kruger National Park , Fragmented landscapes , Climatic changes Effect of human beings on , Ecosystem management , Herbivores Behavior , Biotic communities Effect of human beings on
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/435703 , vital:73180 , DOI 10.21504/10962/435703
Description: Globally, terrestrial mammal populations are facing critical population declines and range contractions owing to habitat fragmentation and destruction, wildlife overexploitation, and climate change driven by expansion of the human population. Mammalian herbivores are integral for maintaining ecosystem structure and functionality. They do this this through herbivory, by acting as prey and cycling soil nutrients. The impacts of herbivores on ecosystems, however, vary with their spatial occupancy which is influenced by interacting bottom-up and top-down factors. Modelling the drivers of herbivore communities is no trivial task given the myriad of potential bottom-up and top-down factors, and the interactions between the two, as well as the species-specific variations in intrinsic functional traits (e.g., foraging strategy, body size, metabolic rate, etc.) influencing herbivore responses (e.g., social structure, space-use, activity patterns, etc.) to these drivers. Consequently, few studies have attempted to model both bottom-up and top-down drivers in structuring herbivore communities, particularly in an African context where predator-prey guilds include multiple species, exposed to high levels of human activity. Therefore, the overarching aim of my research was to quantify the relative effects of both bottom-up and top-down factors driving the herbivore community in the northern Pafuri region of Kruger National Park, South Africa. I utilized a combination of field (i.e., camera trap and vegetation surveys) and analytical (i.e., stable carbon isotopes from faeces and plants) techniques in conjunction with geospatial data to evaluate the impacts of bottom-up (i.e., forage quantity, quality, and water availability) and top-down (i.e., predation and anthropogenic risks) factors on herbivore spatial occupancy and activity patterns. Herbivore responses to bottom-up and top-down factors were species-specific, even among members of the same feeding guild. Specifically, I found that herbivores (varying in body size and foraging strategy) displayed temporal, spatial and in some instances, dietary shifts that reflect species-specific, ecological trade-offs between resource acquisition, and predator and human avoidance. For example, kudu (Tragelaphus strepsiceros) displayed temporal and spatial avoidance of predators and humans, and exhibited previously undocumented levels of seasonal dietary shifts which suggests that the species traded forage acquisition for reduced predation and anthropogenic risks. Further, high levels of human activity appeared to eclipse the risks associated with natural predators resulting in human induced landscapes of fear. For example, warthogs (Phacochoerus africanus) and zebra (Equus quagga) occupied habitats with higher predation risks, but displayed spatial avoidance of nature reserve boundaries which were synonymous with high levels of bushmeat poaching. Most studies focussing on the impacts of bottom-up and top-down drivers neglect to consider the roles that humans play in structuring ecological communities. The results of my thesis, however, emphasize the importance of including anthropogenic drivers when investigating the roles that various bottom-up and top-down factors play in shaping ecological communities. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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Date Issued: 2024-04-05

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The influence of the physical environment on invertebrate larval transport, settlement and recruitment with insights on early-stage physiological performance

- Duna, Oliver Olwethu

Authors: Duna, Oliver Olwethu
Date: 2024-04-05
Subjects: Larvae Physiology , Bivalves , Invertebrates Habitat , Larvae Dispersal , Biological oceanography , Larvae Geographical distribution
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/435663 , vital:73177 , DOI 10.21504/10962/435663
Description: Most marine benthic organisms have a biphasic life cycle whereby the larvae are pelagic, and their distribution, transport and settlement are largely controlled by environmental factors. Among these factors, hydrodynamics have key direct effects. Nearshore water hydrodynamics are strongly influenced by wind. This study investigated whether wind indirectly affects the distribution, settlement and recruitment of invertebrate marine larvae. Additionally, larvae are exposed to a more constant, benign environment than they will experience after settlement, and therefore the possible effects of larval thermal history on the physiological plasticity of settled organisms was also estimated for possible long-term insights into population dynamics. Four sites, two on the western and two on the eastern side of Algoa Bay in Gqeberha (formerly known as Port Elizabeth), South Africa, were chosen for larval collection. Sites at opposite ends of the bay were selected as they were towards either side of the dominant wind directions in this region. At each site, two sampling stations were identified at 300 and 900 metres offshore, with station replicates 300 metres apart. Sampling of marine invertebrate larvae was conducted after two days of westerly or easterly winds at either of the two western or eastern sites. The number of hours of unidirectional wind determined the prevalent wind on the two days prior to sampling. Samples were collected with a plankton pump at three depths; surface, mid-depth and bottom. Simultaneously with plankton sampling, water properties (fluorescence, temperature, zonal and meridional flow, salinity and oxygen) were measured. Settlement/recruitment samples of mussels and barnacles were collected at six sites, two at either edge of the bay and two within the center of the bay. Plastic scouring pads and PVC plastic plates covered with safety-walk, placed at least 30 cm from each other, were used to collect settlers/recruits of mussels and barnacles, respectively. The pads and plates were replaced on a monthly basis for 14 months to quantify monthly settlement/recruitment. At four of the six sites used for quantifying settlement/recruitment, settlers and recruits were collected to measure the physiological responses of these two ontogenetic stages (settlers and recruits) to acute temperature variations which they might experience in the intertidal zone. Three temperature loggers were used to record real time temperature variation at each site over the period (one month) in which the artificial collectors were in position. Factorial ANOVA was used to investigate the effects of wind, depth, site, and distance from the shore on the abundance of larvae in the water column, as well as the effects of month and site on settlement/recruitment. Additionally, multiple regression analyses were used to investigate the effects of physical parameters, including upwelling and dissipation of turbulent kinetic energy, on the abundance of both larvae, settlers and recruits. Distance-based linear models and redundancy analyses were also carried out on the abundances of invertebrate larvae. Correlation analyses were performed to investigate the effect of the number of hours of directional wind on settlement. Lastly, correlation analyses between wind and currents were carried out. The results revealed a link between winds and currents, with wind speed directly proportional to surface current speed, which, as expected, decreased with depth. Current direction was, however, not perfectly aligned with wind direction. Larval distribution, settlement and recruitment were largely associated with the nearshore dissipation of turbulent kinetic energy and upwelling. Thus, overall larval, settler and recruit abundances were indirectly affected by wind. Physiologically, there was no significant difference in oxygen consumption between the juvenile ontogenetic stages (settlers and recruits) of mussels. Recruits exposed to average and maximum temperatures, however, consumed more oxygen than those exposed to low temperatures. Wind and wind-mediated currents as well as temperature have been shown to shape the distribution and shore supply of larvae, and this study contributes to the broad knowledge of population dynamics and replenishment, and the tight relation of abiotic factors affecting biological processes on the shore. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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Date Issued: 2024-04-05

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Wild edible plants in rural home gardens: livelihoods, perceptions, economic value & traditional knowledge

- Mothupi, Frans Makwena

Authors: Mothupi, Frans Makwena
Date: 2024-04-05
Subjects: Wild plants, Edible South Africa , Sustainable livelihood , Traditional knowledge , Economic value , Food security South Africa
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/435885 , vital:73209 , DOI 10.21504/10962/435885
Description: The prevalence of hunger and malnutrition has been steadily increasing in the world over the past decades. The rate of food insecurity was further exacerbated by the COVID 19 pandemic which plunged millions more into hunger as a result of a recovering economy and high food prices. These challenges are mostly experienced in Africa and are estimated to worsen in this region already affected by conflict, poor healthcare, and natural disasters such as floods and droughts. The green revolution in the 1960’s elevated agricultural production to play a pivotal role in the provision of food. However, production focused mainly on the cultivation of staple crops such as rice, wheat, and maize. The reliance on these crops has contributed to the lack of micronutrient intake and consumption of non-diverse diets. Wild edible plants (WEPs) which previously formed a significant part of indigenous people’s diet, have been regarded as an important food source crucial for the alleviation of malnutrition and micronutrient deficiencies. Despite their nutritional qualities, they are often ignored, overlooked, and undermined by agricultural programmes and food security interventions. Additionally, WEPs are largely absent in modern diets, they are often surrounded by negative perceptions, they are economically undervalued, and the indigenous knowledge of these species is under threat. As a result, this study regards WEPs as important resources that can significantly contribute to improved livelihood outcomes such as income, food security and good health. Using the Sustainable Livelihoods Framework, this study evaluated the contribution of WEPs to sustaining livelihoods, providing economic value, and examined how WEPs are perceived as well as the relationship between their knowledge and consumption in rural areas. This study was conducted in rural villages that are under the jurisdiction of the Moletjie and Matlala tribal authorities in the Polokwane and Aganang local municipalities, South Africa. Qualitative and quantitative research methods were employed for data collection. A total of 356 participants were interviewed for this study. Firstly, in-depth interviews were conducted with 20 elderly participants (Chapter 2). Semi-structured interviews were conducted with a total of 120 participants stratified by age, gender, and income groups (Chapter 3). A total of 96 household surveys were conducted in selected villages, this was complemented by direct observations and field surveys of the home gardens (Chapter 4). Questionnaires and freelists were administered to a total of 120 participants also stratified by age, gender, and income groups to collect data on indigenous knowledge of WEPs (Chapter 5). Thematic analysis were performed for interview data (Chapter 2) and data were summarised, descriptive statistics, chi square tests (Chapter 3), Kruskal-Wallis tests (Chapter 4), ANOVA tests and correlation tests (Chapter 5) were performed using SPSS software. The findings show that there has been a major nutrition transition characterised by changed meal composition, patterns, and frequency relating to the consumption of WEPs. The changes can be attributed to increasing western influence characterised by rising urbanisation, western lifestyle of church, school, and employment in an income-based economy dependent on retail stores to fulfil their daily dietary needs. Despite this, WEPs are still valuable to rural people, this is indicated by the fact that traditional foods are made optional at some modern and traditional celebrations. Overall, most of perceptions (65.6%) regarding the consumption of WEPs were positive. The overwhelming majority of respondents agreed or strongly agreed that preparations from the local WEPs are relatively more tasty (98.3%), healthy (96.6%), nutritious (86.7%), and better represent the traditional foods (94.1%). Additionally, participants perceived WEPs to have health benefits in that they have medicinal properties to help prevent diseases, are a good source of energy, highly nutritious and they give strength. Despite these benefits and positive perceptions, most participants expressed doubt over the commercial success of WEPs if they were to compete with cultivated crops in the market. As a result, they perceive the future of WEPs to be bleak as 95% of participants believe that their consumption is in decline. This can be largely attributed to deagrarianisation, climate change, and preference of cultivated foods by the youth. The study also showed that a diversity fruits and vegetables are available in rural home gardens, with cultivated fruits grown in abundance and WEPs available in almost all households (98%). WEPs represented 34% of the total estimated economic value of plants available in rural home gardens. Most of the home gardens produce food to supplement household food supply with only a few households engaged in trading. The trading of WEPs was recorded in 9% of the home gardens while 16% sold cultivated fruits and/or vegetables. Challenges such as lack of water and poor rainfall are shocks which affect the availability, richness, and abundance of home garden produce. WEPs are generally well known in rural areas as participants listed an average of 8.4±2.4 species. There was a significant statistical difference between the number of species listed by age group (p = 0.009) with the elderly listing a higher average number of species (9.3±2.6) compared to adults (8.1±2.5) and the youth (7.8±1.7). Vangueria infausta, Sclerocarya caffra, Ximenia caffra, Amaranthus retroflexus L. retroflexus, Citrullus lanatus,and Cleome gynadra where among the top listed species. There was also a significant positive correlation between the number of listed fruits with number of listed vegetables. The study also found a positive correlation between knowledge of WEPs and consumption. Most of the knowledge about WEPs was learned from a family member (89%), own observation (86%), a village elder (75%). This knowledge was mostly acquired from childhood through oral tradition (63%) and through participation (21%), and consumption (12%). , Thesis (PhD) -- Faculty of Science, Environmental Science, 2024
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Date Issued: 2024-04-05

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A battle of values: analysing the changing attitudes towards African refugees in Europe

- Mannion, Megan Kate

Authors: Mannion, Megan Kate
Date: 2024-04-04
Subjects: Refugees Africa , Refugees Public opinion Europe , Cosmopolitanism , Communitarianism , Racism against Black people , Xenophobia in mass media
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435525 , vital:73165
Description: Cosmopolitanism is a moral perspective that stresses the importance that every human being is an equal and ultimate unit of moral concern. These principles make cosmopolitanism more concerned for and accommodative towards outsiders to a political community. Against the abstraction and universalism of cosmopolitanism, communitarianism emphasizes the role communities play in shaping our individual identities and sees it as justified that the interests and well-being of community members receive priority over those of outsiders. Both these value systems are present in Europe. The question is about which direction the trend has moved in recent decades. This dissertation examines the changing values that inform attitudes toward African refugees in Europe to get at this issue. Have attitudes towards African refugees shifted in a cosmopolitan or a communitarian direction in recent decades? This dissertation examines newspaper articles from The Guardian between 1990 and 2022 to track changes in value. The analysis of these articles uncovered that communitarian values were the most prevalent and stayed the most prevalent from 1990 to 2022. These findings indicate that communitarian values are higher than cosmopolitan values regarding African refugees within the general European context. These findings add to the growing body of knowledge regarding attitude shifts, and they provide a timeline for value changes that can help predict future values and be used in future comparative studies. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2024
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Date Issued: 2024-04-04

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A MIGHTEE Investigation of radio quiet AGN

- Namane, Neo

Authors: Namane, Neo
Date: 2024-04-04
Subjects: Active galactic nuclei , Radio quiet zone , MeerKAT , Near infrared , Stars Formation , Southern African Large Telescope (South Africa : Telescope) , VISTA
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435367 , vital:73151
Description: This study is aimed at being an overview and investigation of the behaviour and morphology of radio quiet (RQ) active galactic nuclei (AGN) in the radio and optical/near-infrared (NIR) bands. It is hoped that a concise description of the relation that exists between accretion activity and star formation (SF) will be achieved through utilization of multiwavelength astronomy analysis. This analysis includes the processing of data acquired from the MeerKAT International GHz Tiered Extragalactic Exploration survey (MIGHTEE), the Southern African Large Telescope (SALT), the Hyper Suprime Camera (HSC) mounted on the Subaru telescope and the VISTA telescope. In this thesis, several targets were observed using SALT spectroscopy, but a redshift of only one of them was obtained. Lastly, it was established that for the sample of RQ AGN studied, the AGN contribute a large fraction of the radio emission observed. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
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Date Issued: 2024-04-04

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A systematic literature review of the current approaches to dream work: global and local trends

- Feris, Eric-John Ricardo

Authors: Feris, Eric-John Ricardo
Date: 2024-04-04
Subjects: Dreams , Dream interpretation , Dreams Psychological aspects , Local and indigenous knowledge systems , Healers , Psychotherapy Cross-cultural studies
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435440 , vital:73157
Description: Dreaming is an inherent and universal aspect of human existence that offers a profound window into the realms of consciousness and cognition. It has captivated the human imagination for centuries, prompting various methods and theories to decipher its significance. Global research underscores the enduring importance of dreams in psychotherapy, expressed through diverse methodologies, techniques, and theoretical models. Curiously, within the South African context, a cultural landscape rich in traditional healing, there exists a noticeable lack of research concerning the utilisation of dreams in therapy. This systematic literature dove into 30 articles which remained after applying the systematic literature review strict inclusion and exclusion criteria of the literature searches. From these articles, the review delved into the multifaceted world of dream work, investigated prevailing approaches and themes both on a global scale and within the South African context, and addressed three key research questions: (1) What themes can be identified from a review of current approaches to dream work globally? (2) What themes can be identified from a review of current approaches to dream work locally? (3) What are the practical implications for working with dreams according to global and local themes? A thematic analysis of the literature identified three overarching themes: (1) Psychological approaches to dream work, (2) Psychiatric and medical approaches to dream work, and (3) Socio-cultural approaches to dreams. These findings highlight the necessity of recognising cultural nuances and, underscores the importance of developing a flexible, culturally sensitive framework for dream work, and advocates for the adaptation of global dream work methodologies into culturally specific approaches, fostering psychotherapeutic benefits tailored to the South African context. The research serves as a stepping stone to further investigation into the techniques and approaches of dream work in South Africa, ultimately contributing to the broader field of dream analysis. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
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Date Issued: 2024-04-04

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Acacia dealbata invasion and clearing in Upper Tsitsana communal areas of South Africa: human perceptions and ecological impacts

- Coka, Nwabisa

Authors: Coka, Nwabisa
Date: 2024-04-04
Subjects: Restoration ecology South Africa Eastern Cape , Acacia dealbata , Invasive plants South Africa Eastern Cape , Working for Water Programme , Invasive plants Control South Africa Eastern Cape
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/434876 , vital:73113
Description: The number of invasive alien plants in South Africa and globally continue to increase mostly due to increased human movement and climate change. It is estimated that approximately 10 000 hectares of South Africa’s terrestrial land is invaded by invasive alien species. Recent studies have reported that invasion by invasive alien plants cost South Africa billions of Rands every year through loss of water and ecosystem services. Although much has been done to understanding invasion trends, patterns, and processes in South Africa, little is knowns regarding human benefits linked to alien plant invasion as well as human perceptions regarding management interventions, particularly clearing by the national Working for Water programme. This thesis took a socio-ecological approach to assess (i) local people perceptions and knowledge of Acacia dealbata invasion and clearing, and (ii) extent of grazing grass diversity and composition recovery following A. dealbata clearing. To answer the above-mentioned objectives, both qualitative (face-to-face interviews) and quantitative (vegetation surveys) methods were used in grasslands located in upper Tsitsana catchment, South Africa. Results from the 165 interviews conducted in six villages show that most villagers are aware of A. dealbata in the area, but do not know that it is an invasive alien plant. Respondents accrue several benefits from the plant that include firewood (98% across all villages), construction pools (34% across all villages), and shade (3% across all villages). Respondents identified several costs associated with A. dealbata invasion, such as roots damage to houses (37% across all villages), hindering growth of crops (15% across all villages), and takes up yard space (29% across all villages). Most of the villages ranked the effects of A. dealbata on grazing as highly severe. Villages indicated that the Working for Water clearing programme presents them with socio-economic benefits such as employment and money. Some villagers noted that the clearing of A. dealbata in the area restores grazing grass (62% across all villages) and water (32% across all villages). Based on these interview survey results, the study concludes that A. dealbata has both costs and benefits that support local people’s livelihoods; therefore, its management should consider views for local users. Grass surveys conducted in 1 m2 quadrats that were replicated 15 times across four paired A. dealbata cleared and grassland sites showed that the removal of A. dealbata facilitates the recovery of native grasses. Of the 14 different grazable grass species that were identified across all quadrats only one (Bulbostylis sp.) is not palatable to livestock. Although grass cover was significantly (p < 0.05) higher in the grasslands than the cleared patches, grass richness was significantly (p < 0.05) higher in the cleared patches an indication that recovery of different grasses is taking place. Based on these vegetation survey results; the study concludes that recovery of grazing grasses after A. dealbata clearing four years ago is following a positive trajectory as the cleared sites are looking like the grassland sites. Overall, the study recommends that management of A. dealbata in Tsitsana landscape requires a socio-ecological approach to understand user benefits whilst at the same time developing measure to control the plant. The study has provided evidence that A. dealbata clearing facilitates passive restoration of grazing grass and local villages are aware of these restoration benefits. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
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Date Issued: 2024-04-04

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Application of the modified pitman and swat models for groundwater recharge estimation in the upstream area of the Uitenhage artesian basin, South Africa

- Wasswa, Peter

Authors: Wasswa, Peter
Date: 2024-04-04
Subjects: Hydrologic models , Groundwater recharge , Runoff Mathematical models , Rain and rainfall Mathematical models , Water-supply Management , Artesian basins South Africa Eastern Cape
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435400 , vital:73154
Description: The world's most plentiful source of freshwater is thought to be groundwater. During extended dry times, it serves as an essential storage component and guards against environmental catastrophes. Despite its critical functions in the aforementioned scenarios, it is often insufficiently understood and inadequately managed. As a result, it calls for the adoption of integrated methods to comprehend the dynamics of groundwater recharge. Thus, the current study evaluated the applicability and suitability of the Modified Pitman and SWAT models for groundwater recharge estimation in the upstream area of UAB for the period that spanned from 1993 to 2021. It was achieved by using a qualitative conceptual-perceptual model to inform the two hydrological models, Modified Pitman, and SWAT. The developed qualitative conceptual-perceptual model depicted the dominancy of irregularly folded and fractured TMG rock outcrops coupled with fault systems in the upstream area. In the downward section, TMG is overlaid by the aquiclude from the Uitenhage Group which is responsible for the artesian conditions. Groundwater potential zones were classified as Poor, Fair, Good, and Excellent, with 65.4% and 8.7% of the upstream area attributed to Good and Excellent zones respectively. Both Modified Pitman and SWAT predicted decreasing rates of groundwater recharge in the upstream area over time, though Mann-Kendal trend tests done at 5% signifance level depicted significant decreasing rates in SWAT predicted recharge compared to Modified Pitman predicted recharge. The two models did also predict recharge and other water balance components with differing peaks, lows and timings. Modified Pitman predicted mean annual recharge of 63.3-92.8 mm where as SWAT predicted mean annual recharge of 14.4-182.8 mm. In reference to earlier findings within TMG areas, estimated percentages of groundwater recharge were close to those simulated by both Pitman and SWAT models. Modified Pitman and SWAT models appear to both be reasonable tools to estimate recharge in TMG setting, producing relatively similar results to one another and to other regional estimates. Since the current study estimated low recharge rates (Modified Pitman; ~9.3-13.6% MAP), (SWAT; ~2.1-26.7% MAP) which are close to those predicted in other TMG areas, the study recommends exercising caution when developing a water supply strategy in the current study area. The recharge rates within the pertinent recharging areas should be considered when designing and sitting abstraction points such as boreholes and a sustainable abstraction rate in any one borehole for improved sustainable management of groundwater resources. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2024
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Date Issued: 2024-04-04

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Aptamer-based biosensor for prostate specific antigen detection using cobalt phthalocyanine-exfoliated graphite composites

- Benise, Emihle

Authors: Benise, Emihle
Date: 2024-04-04
Subjects: Aptamer , Exfoliated graphite nano-platelets , Phthalocyanines , Impedance spectroscopy , Prostate-specific antigen
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/434850 , vital:73110
Description: The work focuses on the development of biosensors and their use for the detection of prostate specific antigen (PSA). Four cobalt phthalocyanines (CoPcs) complexes: (1) cobalt tetra pyridyloxy phthalocyanine, (2) cobalt tetra acetamidophenoxy phthalocyanine, (3) cobalt tris(acetamidophenoxy) mono benzoic acid phthalocyanine, and (4) cobalt tris(acetamidophenoxy) mono propionic acid phthalocyanine, an exfoliated graphite (EG), and aptamer are used to make probes for PSA detection. Each complex is π-π stacked onto the EG to form EG-CoPc(π-π) hybrid which was used to modify a glassy carbon electrode (GCE). EG and CoPc were also used to modify the GCE sequential (seq) with CoPc on top to give GCE-EG-CoPc(seq). For the detection PSA, PSA specific aptamer was either sequential added or covalently linked to complexes 3 and 4 on the modified electrodes and was only sequentially added onto complexes 1 and 2 modified electrodes. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were the techniques used for the detection of PSA. The electrodes were found to be selective in bovine serum albumin, glucose and cysteine and stable when 50 DPV scans were run. Electrodes gave good % recovery when human serum was spiked with different PSA concentrations. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
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Date Issued: 2024-04-04

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Attitudes and achievement in statistics: a meta-analytic and functional near-infrared spectroscopy approach

- Wagenaar, Emma Kate

Authors: Wagenaar, Emma Kate
Date: 2024-04-04
Subjects: Statistics Study and teaching , fNIRS , Dorsolateral prefrontal cortex , Learning, Psychology of , Academic achievement
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435490 , vital:73162
Description: Statistics anxiety describes the extensive worry and apprehension that students may experience when faced with statistics content as part of their university curriculums. Student’s perfunctory disposition towards statistics has been indicated to negatively affect performance outcomes in statistics courses. Two meta-analyses were conducted to investigate the relationship between statistics anxiety and achievement in statistics. The first meta-analysis was inclusive of 22 studies investigating the relationship attitudes towards statistics and achievement, whilst the second meta-analysis focused on the relationship, primary amongst Psychology students. Student’s attitudes towards statistics were measured using the Survey of Attitudes Towards Statistics (SATS), whilst achievement in statistics courses was quantified using different outcome measures. Finding from the meta-analysis were supplemented by cortical mapping of the neural correlates of statistical reasoning using functional near-infrared spectroscopy (fNIRS). Results from the meta-analysis indicated a small significant relationship between university students’ Affect, r = 0.28, Value, r = 0.22 and Difficulty, r = 0.18, and subsequent achievement in statistics courses. A medium significant relationship between Cognitive Competence, r = 0.31, and achievement was also noted. Findings from the second meta-analysis, indicated a medium, significant relationship between Affect, r = 0.32, and Cognitive Competence, r = 0.35, and achievement. Moreover, a small significant relationship was found between Value, r = 0.24, and Difficulty, r = 0.23, in relation to achievement in statistics courses. Case study analysis of the neural correlates of statistics reasoning revealed varied signal quality findings of cortical mapping of the neural correlates of statistics in the dorsolateral prefrontal cortex (DLPFC). Moreover, seed-based correlation analysis indicated cortical activation of the dorsolateral prefrontal cortex paired with diverse prefrontal regions. Recommendations from the study include improvements to the fNIRS research design and the inclusion of larger samples to investigate the cortical mapping of the DLPFC in relation to statistics reasoning and statistics anxiety. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
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Date Issued: 2024-04-04

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Case in modern standard Arabic

- Ghammaz, Hamzah Saleh Theyab

Authors: Ghammaz, Hamzah Saleh Theyab
Date: 2024-04-04
Subjects: Arabic language Syntax , Arabic language Case , Minimalist theory (Linguistics) , Grammar, Comparative and general Verb phrase , Predicate , Tritransitive verb , Grammar, Comparative and general Clitics
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/435593 , vital:73171 , DOI 10.21504/10962/435593
Description: This thesis provides a novel account of case checking in Modern Standard Arabic (henceforth MSA). It argues against the concept that nominative case in topic and comment structures is default. Default or inherent case is not related to case filter, nor is it assigned by any syntactic method. Some linguists claim that the default case in Arabic language is employed only when no case assigner is available. I argue, in light of the minimalist program (henceforth MP), that default (inherent) case is always a problem for syntactic theory and that the nominative case which the topic and comment sentences bear is valued by a functional head. The topic and comment constructions contain a predicational head (Pred)- a functional head, that is equivalent to vP which occurs in verbal constructions. The head of PredP is accountable for nominative case value on the topic and comment structures. This thesis also provides a novel paradigm regarding the clitics that appear at the end of verbs in MSA. This paradigm proves that these clitics are not agreement, tense, nor mood markers but rather Verbal Case markers and it provides a minimalist program account to explain case checking on verbs in MSA. Regarding sentence initial DP, and contra to the proposal that in SVO sentence initial DP is a subject, I have scrutinised the nature of this DP and provided enough evidence that it is a topic. Additionally, I have investigated the relationship between agreement asymmetry and the position of the subject in MSA from the minimalist feature inheritance account viewpoint. Mainly, I reviewed null pro hypothesis which proved to be redundant to account for the derivation of VSO or SVO word orders. I have also proved what were considered agreement markers are not agreement markers but resumptive pronouns. Finally, I proved that there is not agreement asymmetry in MSA. Agreement pattern in MSA results from the agree operation and it is achieved under Probe-Goal alignment; regardless of whether the Goal is raised up to Spec-TP or remains in situ (Spec-VP), the agreement is not supposed to change. This conclusion is in harmony with the principles of MP Agree Theory. , Thesis (PhD) -- Humanities, Linguistics and Applied Language Studies, 2024
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Date Issued: 2024-04-04

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Developing a community of practice to promote the use of biological control in the integrated management of Prosopis in South Africa

- Van Staden, Gretha

Authors: Van Staden, Gretha
Date: 2024-04-04
Subjects: Mesquite South Africa Northern Cape , Community of practice , Stakeholder participation , Mesquite Control , Invasive plants Biological control , Prosopis
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/434998 , vital:73122
Description: Prosopis spp. are non-native species present in the arid parts of southern Africa. These trees originated in the Americas and were first introduced as a source of fodder, shade, and wood, but have become invasive, negatively impacting local biodiversity, and disrupting the delivery of ecosystem services. Some species of Prosopis hybridise freely, complicating identification and subsequent control. The control of Prosopis in the Northern Cape Province of South Africa is still contentious, because of the perceived benefits to some landowners. The effectiveness of biological control agents to control the spread of Prosopis has been quantified, more damaging agents have been considered in recent years because of the continued increase in Prosopis density. Research into the establishment of a Community of Practice (CoP) to address the differences in perceptions regarding the control of Prosopis in the Northern Cape Province is considered an appropriate starting point to conceptualise the challenges to the successful integrated management of Prosopis. As farmers are the main stakeholders involved with Prosopis control, understanding the role of farmers and the functioning of farming enterprises in the Northern Cape is imperative for the development of both a CoP as well as the appropriate management of Prosopis. To foster engagement with as many stakeholders as possible, workshops dealing with biological control as part on an integrated approach to the control of Prosopis were held in towns in the Northern Cape Province: Groblershoop, Brandvlei, Kenhardt, Upington, Prieska and Williston. Some of the main concerns of the landusers include the host specificity of the released biocontrol agents, as well as increased transparency and communication. This is especially in regards to the research on present and future biological control agents that will possibly improve the perceptions of stakeholders. The mechanical harvesting and use of biomass as a control method was supported, especially where farmers were removing Prosopis from their properties, leaving large amounts of biomass in the veld. Continued research into Prosopis in the Northern Cape needs to consider the possibility of secondary invasions, especially in areas where native bush encroachment is already a concern. The impact of clearing in terms of natural grazing and animal improvement needs to be quantified, to conceptualise the importance of maintaining better veld quality versus using Prosopis for fodder. Biological control targeting not only the reproductive output of the trees, but also the standing biomass has support from the majority of the land users in the Northern Cape Province following these workshops and this study shows the importance of a socio-ecological approach to the control of landscape scale invasion. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
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Date Issued: 2024-04-04

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Educators’ experiences of psychosocial support workshops during COVID-19 in Eastern Cape, South Africa

- Mabaso, Rendani Mirriam

Authors: Mabaso, Rendani Mirriam
Date: 2024-04-04
Subjects: Educators Mental health South Africa Eastern Cape , Psychosocial support system , COVID-19 Pandemic, 2020-2023 Influence , Community psychology , Service learning
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435457 , vital:73159
Description: There is growing awareness of the value and central role of immediate and long-term mental health and psychosocial support (MHPSS) interventions, especially during times of crisis such as Covid-19. The World Health Organization has identified the education sector as a crucial intervention site for public mental health promotion. In collaboration with members of the Makhanda education community, the Rhodes University Community Engagement office identified psychosocial support for educators and educational practitioners as a key societal and educational challenge. Focusing specifically on the experiences of educators, this study sought to solicit their experiences of MHPSS workshops in a rural city of the Eastern Cape province of South Africa. Focus groups with educators and educational practitioners in non-government organisations, care centres and other educational settings who participated in the psychosocial support workshops were conducted. Data was analysed using community psychology’s social action framework. Four broad themes emerged from the data: the responsibilisation of educators during and post-Covid-19, educators’ resilience and support for each other, educators’ mental health promotion through psychosocial support workshops, and top-down intervention strategies that fall short in addressing educators’ and learners’ needs. This study demonstrates the value of university-community partnerships in education settings which are key sites for public mental health promotion. In this study, I advocate psychosocial support as a standard practice available for educational practitioners and show how professional training programmes in higher education can be responsive to societal challenges via collaborative approaches. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
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Date Issued: 2024-04-04

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Elucidation of the roles of the carbonic anhydrase enzymes, CanA & CanB, in the physiology of Mycobacterium smegmatis

- Jackson, Gabriella Teresa

Authors: Jackson, Gabriella Teresa
Date: 2024-04-04
Subjects: Mycobacterium tuberculosis , Mycobacterium smegmatis , Carbonic anhydrase , CRISPR , Homologous recombination , Drug targeting
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/435299 , vital:73145
Description: The bacterial pathogen Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis (TB) and one of the leading infectious causes of death globally. The success of Mtb as a pathogen depends on its ability to detect and respond to a variety of physical and chemical stresses it encounters during infection of its human host. These environmental stresses include shifts in temperature, oxygen concentration, osmolarity and nutrient availability. Mtb is, in addition, exposed to changes in pH and CO2 concentration in the intracellular and extracellular environments it inhabits, which the bacterium has to adapt to in order to ensure its growth, survival and/or persistence during infection. Carbonic anhydrases (CAs) are a widely distributed family of enzymes that catalyse the reversible hydration of carbon dioxide (CO2) to bicarbonate (HCO3−) in the reaction: CO2 + H2O ⇄ HCO3− + H+. In microbes, CA activity is important for the activity of enzymes involved in carbon fixation as well as for maintaining pH homeostasis. Mtb is known to express three CAs, encoded by the Rv3588c, Rv1284 and Rv3273 genes (canA, canB and canC, respectively). The role(s) of these CA enzymes in the physiology of Mtb and other mycobacterial species, such as Mycobacterium smegmatis (Msm), has not been elucidated to date. To gain insights into the function of the CanA and CanB enzymes in mycobacterial species, we generated both canA and canB knockdown (KD) and knockout (KO) mutants in the fast-growing mycobacterial species, Msm, and analysed their growth phenotypes under several growth conditions where CA activity is known to be required. Notably, Msm lacks the CanC homologue, which makes it an ideal surrogate to focus on CanA and CanB. The Msm canA KD mutant was found to display a growth defect following anhydrotetracycline (ATc)-mediated gene silencing at atmospheric (low) CO2 concentrations [~0.035% CO2 (v/v)]. The growth defect could be rescued by incubating cells at physiological (high) CO2 concentrations [~5% CO2 (v/v)] or by supplementing the growth media with either HCO3− or the metabolic end-products of certain HCO3−-dependent-carboxylase enzymes at low CO2 concentrations. The ability of these compounds to rescue the growth of the canA KD mutants was, however, dependent on the extent of ATc-mediated gene silencing, suggesting that the canA gene is required for Msm growth at both low and high CO2 concentrations. This was confirmed by our findings that canA could only be genetically inactivated when a second copy of the gene was provided on the chromosome in trans, regardless of the CO2 concentration used. In contrast to our observations for canA, no differences in the growth phenotypes of the Msm wild type (WT) and canB KD or knockout (KO) mutant strains were observed following silencing or inactivation of the canB gene at either low or high CO2 concentrations or different pH values. These observations suggest that, in contrast to canA, the canB gene is dispensable for the growth of Msm under standard laboratory growth conditions. The canB KO mutant strain, nevertheless, displayed a slight decrease in its ability to form biofilms when compared to the WT strain, which could be restored by genetic complementation. CanB activity may, therefore, be required to promote bacterial growth and/or survival under biofilm conditions where CO2 diffusion into cells is limited, a phenomenon that has recently been observed in other microbes. Further studies are required to confirm the role of CanB in biofilm formation and to determine how the different CA enzymes cooperate to promote the growth and survival of mycobacterial species in the various environments they are known to inhabit. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2024
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Date Issued: 2024-04-04

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English morphological awareness and reading comprehension in deaf and hearing grade 3 to 7 learners from Lesotho

- Tšehla, Puleng Magret

Authors: Tšehla, Puleng Magret
Date: 2024-04-04
Subjects: Grammar, Comparative and general Morphology , Reading comprehension Lesotho , Deaf students Lesotho , Sign language , Reading (Primary) Ability testing Lesotho , Literacy Lesotho
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/${Handle} , vital:73169
Description: There is a noticeable literacy crisis observed in both Deaf and hearing learners from Lesotho. This study investigates the English Morphological Awareness and reading comprehension of 26 Deaf and 82 hearing learners enrolled in grades 3 to 7 in two schools in Lesotho. This study employs a correlational cross-sectional quantitative design. Each participant completed two literacy assessment tasks: a reading comprehension task and a Morphological Awareness task. The Morphological Awareness task encompassed five subtasks that assessed the learners’ inflectional, derivational, and compound awareness. The results of these assessments are analysed through appropriate statistical analyses. In addition, errors made by the Deaf and hearing learners on the literacy assessments are compared and analysed. This analysis determines the types of errors made by each group and identifies the factors that influence these errors. The performance of both groups in terms of task scores, in general, was low. Deaf learners and hearing learners’ performance on the tasks was similar. This outcome contradicts most previous studies, which indicate that Deaf learners typically exhibit lower levels of Morphological Awareness development and reading comprehension compared to their hearing counterparts. The results of this study also suggest that there is a statistically significant relationship between Morphological Awareness and reading comprehension in both groups. Finally, Deaf and hearing learners made similar errors on the tasks. There was some evidence of influence from both the Deaf and hearing learners’ first languages (Sesotho and Lesotho Sign Language, respectively). The study demonstrates the need for more explicit morphological instruction to improve both Deaf and hearing learners’ literacy. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Language Studies, 2024
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Date Issued: 2024-04-04

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