Functional significance of mixed-species groups for zebra (Equus quagga) in savanna habitats
- Corry-Roberts, Carys Alexandra
- Authors: Corry-Roberts, Carys Alexandra
- Date: 2024-04-04
- Subjects: Herding behavior in animals , Zebras Food , Foraging , Zebras Behavior , Zebras Conservation , Herbivores Habitat
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/434925 , vital:73116
- Description: Globally, herbivore populations are facing decline, which threatens their crucial role within the ecosystems they inhabit. Herbivores are essential to ecosystem structure and function because they act as prey for higher trophic levels, cycle soil nutrients, and alter vegetation structure. Understanding the drivers that shape herbivore habitat use and selection are therefore critical for making informed conservation and management decisions. Like all prey species, herbivores must balance a trade-off between acquiring resources and avoiding predation which is influenced by a number of species-specific intrinsic traits and various ecological drivers. Herbivores can also track risk over space and time, and certain habitat structures and landscape features can influence risk perception; this is termed the landscape of fear. To mitigate the risk-reward trade-off, herbivores employ a suite of behavioural responses. Group formation is likely the most well-documented of these responses. However, grouping results in the information-competition trade-off, wherein group members may obtain valuable information regarding the location of resources and/or the risk of predation, but may suffer from increased competition, especially among larger group sizes. Mixed-species groups—an assemblage of two or more species in close spatial association—have the potential to mitigate some of the competitive costs of larger conspecific groups and enhance the anti-predator and/or foraging benefits of grouping. African savannas provide a particularly useful natural laboratory to study mixed-species groups, due to the high diversity of prey species and habitat heterogeneity present. Previous studies have investigated the mixed-species effect within these systems, but have yet to quantify some of the identity-dependent costs and benefits associated with mixed-species herding. Thus, the overall aim of my study was to quantify the functional significance of mixed-species groups for zebra (Equus quagga) herding with two of their most common herding partners, impala (Aepyceros melampus) and wildebeest (Connochaetes taurinus). My study was conducted at multiple spatial scales in the southern portion of the Kruger National Park, South Africa between 2021 and 2022. I found that mixed-species herding altered zebra landscape use, resulting in a quantifiable intensification of habitat use compared to when they herd with conspecifics. I did not observe significant habitat expansion for zebra in mixed-species herds compared to single-species herds, likely because the anti-predator benefits of mixed-species herding convey enhanced foraging opportunities in already-safe habitats. Zebra foraging with impala achieved greater foraging success and experienced lower levels of competition, compared to zebra foraging with wildebeest. However, compared to foraging with conspecifics, the levelled landscape of fear zebra experienced when foraging with wildebeest resulted in increased foraging success across the landscape. My findings highlight the context-dependency of the costs and benefits associated with different herding partners for zebra, and suggest that in mixed-species herds with wildebeest, zebra experience increased potential fitness benefits compared to herding with impala or conspecifics. Overall, the findings of my study suggest that mixed-species herding is an important tool in the suite of anti-predator behaviours employed by prey species, and one with significant implications for survivorship, habitat use, and ultimately, community level interactions. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Authors: Corry-Roberts, Carys Alexandra
- Date: 2024-04-04
- Subjects: Herding behavior in animals , Zebras Food , Foraging , Zebras Behavior , Zebras Conservation , Herbivores Habitat
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/434925 , vital:73116
- Description: Globally, herbivore populations are facing decline, which threatens their crucial role within the ecosystems they inhabit. Herbivores are essential to ecosystem structure and function because they act as prey for higher trophic levels, cycle soil nutrients, and alter vegetation structure. Understanding the drivers that shape herbivore habitat use and selection are therefore critical for making informed conservation and management decisions. Like all prey species, herbivores must balance a trade-off between acquiring resources and avoiding predation which is influenced by a number of species-specific intrinsic traits and various ecological drivers. Herbivores can also track risk over space and time, and certain habitat structures and landscape features can influence risk perception; this is termed the landscape of fear. To mitigate the risk-reward trade-off, herbivores employ a suite of behavioural responses. Group formation is likely the most well-documented of these responses. However, grouping results in the information-competition trade-off, wherein group members may obtain valuable information regarding the location of resources and/or the risk of predation, but may suffer from increased competition, especially among larger group sizes. Mixed-species groups—an assemblage of two or more species in close spatial association—have the potential to mitigate some of the competitive costs of larger conspecific groups and enhance the anti-predator and/or foraging benefits of grouping. African savannas provide a particularly useful natural laboratory to study mixed-species groups, due to the high diversity of prey species and habitat heterogeneity present. Previous studies have investigated the mixed-species effect within these systems, but have yet to quantify some of the identity-dependent costs and benefits associated with mixed-species herding. Thus, the overall aim of my study was to quantify the functional significance of mixed-species groups for zebra (Equus quagga) herding with two of their most common herding partners, impala (Aepyceros melampus) and wildebeest (Connochaetes taurinus). My study was conducted at multiple spatial scales in the southern portion of the Kruger National Park, South Africa between 2021 and 2022. I found that mixed-species herding altered zebra landscape use, resulting in a quantifiable intensification of habitat use compared to when they herd with conspecifics. I did not observe significant habitat expansion for zebra in mixed-species herds compared to single-species herds, likely because the anti-predator benefits of mixed-species herding convey enhanced foraging opportunities in already-safe habitats. Zebra foraging with impala achieved greater foraging success and experienced lower levels of competition, compared to zebra foraging with wildebeest. However, compared to foraging with conspecifics, the levelled landscape of fear zebra experienced when foraging with wildebeest resulted in increased foraging success across the landscape. My findings highlight the context-dependency of the costs and benefits associated with different herding partners for zebra, and suggest that in mixed-species herds with wildebeest, zebra experience increased potential fitness benefits compared to herding with impala or conspecifics. Overall, the findings of my study suggest that mixed-species herding is an important tool in the suite of anti-predator behaviours employed by prey species, and one with significant implications for survivorship, habitat use, and ultimately, community level interactions. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
High-altitude temporary systems and macroinvertebrate composition in La Nina cycle, Maloti-Drakensberg
- Authors: Moyo, Sibusisiwe
- Date: 2024-04-04
- Subjects: Maloti-Drakensberg Transfrontier Conservation and Development Area (Lesotho and South Africa) , Mountain animals , Tarn , Mountain watersheds , Biodiversity , Macroinvertebrate , Ecological community assembly
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/434963 , vital:73119
- Description: The Maloti-Drakensberg Mountain is an important water catchment area for South Africa and Lesotho. It is rich in biodiversity in terms of endemic flora and fauna and has a high density of temporary wetlands in the form of Afromontane tarns and rock pools. There is, however, limited information on the distribution of macroinvertebrates in these ecosystems and environmental factors that drives their composition. To that end, this study investigated macroinvertebrate diversity and the effect of environmental factors on community assemblage in the Maloti-Drakensberg Mountain temporary wetlands, specifically tarns and rock pools. The main aims were to describe the abundance, diversity, and distribution of macroinvertebrates in temporary wetlands in the Maloti-Drakensberg Mountain. Furthermore, it aimed to investigate the effect of environmental variables on habitat structuring, spatial variations, and macroinvertebrate community composition in tarns and rockpools in the Maloti-Drakensberg Mountain. Seventy temporary wetlands (29 tarns and 41 rock pools) were surveyed over a once-off sampling (3 March – 7 April 2022). The wetlands were from 3 provinces including Eastern Cape, Free State, and KwaZulu-Natal. 15278 individual macroinvertebrates from 13 orders, 35 families, and 46 genera were collected and identified. Species accumulation curves incorporating both tarns and rock pools showed that observed results were significantly lower than Chao 1 and Chao 2 estimates meaning that the sampled sites were not enough to provide a comprehensive picture of the biodiversity in the region. This was also observed for rock pools when the temporary wetlands were analysed separately, however, the Chao 1 and Chao 2 values for tarns were almost equal to the observed values implying that sampled sites were enough to give a detailed picture of macroinvertebrate composition in tarns. Tarns and rock pools were significantly different in terms of species richness and Shannon-Wiener diversity index but showed no significant differences for relative abundance and Pielou’s evenness. Of the 35 families identified, 19 were considered core taxa with Dytiscidae and Corixidae being the most dominant. Additionally, there was moderate Nestedness metric based on Overlap and Decreasing Fill (NODF) value of 33.05369, with 32 out of 35 families being idiosyncratic. Predators were the dominant feeding group with omnivores being the least common. Non-Metric multi-Dimensional Scaling (NMDS) and PERMANOVA results showed that tarns and rock pools supported distinctly different macroinvertebrate communities per wetland type and location respectively. Physicochemically, tarns and rock pools were significantly different in terms of water temperature, depth, area, and chlorophyll-a concentration with tarns exhibiting higher values. Temporary wetlands in the sampled localities differed in terms of pH, EC, DO, water temperature, altitude, and phosphate. Principal Component Analysis showed that tarns were positively associated with area and depth whereas rock pools with phosphate. Akaike’s Information Criterion (AICc) selection showed that area, pH, and water temperature were significantly influencing community assemblage in temporary wetlands. Furthermore, area significantly influenced all four measured biodiversity indices: relative abundance, species richness, Pielou’s evenness and Shannon-Wiener Index, with water temperature also influencing relative abundance and altitude, species richness. Overall, the species composition showed that the sites were sampled later in the hydroperiod as evidenced by the dominance of active dispersers. The extended distribution of Prosthetops gladiator in the Eastern Cape highlights the need for extensive surveys to provide valuable insight into the distribution patterns of macroinvertebrates in the region. Furthermore, the interplay between physicochemical variables and biodiversity indices emphasized area, water temperature and pH as significant factors. However, their limited explanatory power suggests that obscure factors also influence the diversity cementing the need for further exploration of these enigmatic systems. Taxonomic challenges, especially regarding large branchiopods, hindered precise species distribution and conservation status determination. This study is the first to provide a comprehensive list of macroinvertebrates from temporary wetlands in the Maloti-Drakensberg Mountain. These results establish a valuable baseline for future biological monitoring studies, particularly in assessing species composition and responses to anthropogenic activities. It is a timeous study considering the sensitivity of these systems to climate change as they act as sentinel sites hence the need for foundational data on which to make future projections. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Authors: Moyo, Sibusisiwe
- Date: 2024-04-04
- Subjects: Maloti-Drakensberg Transfrontier Conservation and Development Area (Lesotho and South Africa) , Mountain animals , Tarn , Mountain watersheds , Biodiversity , Macroinvertebrate , Ecological community assembly
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/434963 , vital:73119
- Description: The Maloti-Drakensberg Mountain is an important water catchment area for South Africa and Lesotho. It is rich in biodiversity in terms of endemic flora and fauna and has a high density of temporary wetlands in the form of Afromontane tarns and rock pools. There is, however, limited information on the distribution of macroinvertebrates in these ecosystems and environmental factors that drives their composition. To that end, this study investigated macroinvertebrate diversity and the effect of environmental factors on community assemblage in the Maloti-Drakensberg Mountain temporary wetlands, specifically tarns and rock pools. The main aims were to describe the abundance, diversity, and distribution of macroinvertebrates in temporary wetlands in the Maloti-Drakensberg Mountain. Furthermore, it aimed to investigate the effect of environmental variables on habitat structuring, spatial variations, and macroinvertebrate community composition in tarns and rockpools in the Maloti-Drakensberg Mountain. Seventy temporary wetlands (29 tarns and 41 rock pools) were surveyed over a once-off sampling (3 March – 7 April 2022). The wetlands were from 3 provinces including Eastern Cape, Free State, and KwaZulu-Natal. 15278 individual macroinvertebrates from 13 orders, 35 families, and 46 genera were collected and identified. Species accumulation curves incorporating both tarns and rock pools showed that observed results were significantly lower than Chao 1 and Chao 2 estimates meaning that the sampled sites were not enough to provide a comprehensive picture of the biodiversity in the region. This was also observed for rock pools when the temporary wetlands were analysed separately, however, the Chao 1 and Chao 2 values for tarns were almost equal to the observed values implying that sampled sites were enough to give a detailed picture of macroinvertebrate composition in tarns. Tarns and rock pools were significantly different in terms of species richness and Shannon-Wiener diversity index but showed no significant differences for relative abundance and Pielou’s evenness. Of the 35 families identified, 19 were considered core taxa with Dytiscidae and Corixidae being the most dominant. Additionally, there was moderate Nestedness metric based on Overlap and Decreasing Fill (NODF) value of 33.05369, with 32 out of 35 families being idiosyncratic. Predators were the dominant feeding group with omnivores being the least common. Non-Metric multi-Dimensional Scaling (NMDS) and PERMANOVA results showed that tarns and rock pools supported distinctly different macroinvertebrate communities per wetland type and location respectively. Physicochemically, tarns and rock pools were significantly different in terms of water temperature, depth, area, and chlorophyll-a concentration with tarns exhibiting higher values. Temporary wetlands in the sampled localities differed in terms of pH, EC, DO, water temperature, altitude, and phosphate. Principal Component Analysis showed that tarns were positively associated with area and depth whereas rock pools with phosphate. Akaike’s Information Criterion (AICc) selection showed that area, pH, and water temperature were significantly influencing community assemblage in temporary wetlands. Furthermore, area significantly influenced all four measured biodiversity indices: relative abundance, species richness, Pielou’s evenness and Shannon-Wiener Index, with water temperature also influencing relative abundance and altitude, species richness. Overall, the species composition showed that the sites were sampled later in the hydroperiod as evidenced by the dominance of active dispersers. The extended distribution of Prosthetops gladiator in the Eastern Cape highlights the need for extensive surveys to provide valuable insight into the distribution patterns of macroinvertebrates in the region. Furthermore, the interplay between physicochemical variables and biodiversity indices emphasized area, water temperature and pH as significant factors. However, their limited explanatory power suggests that obscure factors also influence the diversity cementing the need for further exploration of these enigmatic systems. Taxonomic challenges, especially regarding large branchiopods, hindered precise species distribution and conservation status determination. This study is the first to provide a comprehensive list of macroinvertebrates from temporary wetlands in the Maloti-Drakensberg Mountain. These results establish a valuable baseline for future biological monitoring studies, particularly in assessing species composition and responses to anthropogenic activities. It is a timeous study considering the sensitivity of these systems to climate change as they act as sentinel sites hence the need for foundational data on which to make future projections. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
The 2019 SASBO Bank Workers’ Strike in South Africa: unpacking labour responses to the Fourth Industrial Revolution
- Authors: Moyo, Wisdom Ntandoyenkosi
- Date: 2022-10-14
- Subjects: Industry 4.0 , Fourth Industrial Revolution , Banks and banking South Africa , SASBO , Labor unions South Africa , Strikes and lockouts Bank employees South Africa , Working class South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406774 , vital:70306
- Description: The Fourth Industrial Revolution (4IR) is a global phenomenon, affecting workers and trade unions worldwide with the increased automation, including digitisation, of work. Although the 4IR has often been presented as an impersonal technological force that society must just accept, it is in fact rooted in the evolution of capitalist society: it is the latest in a series of industrial revolutions and restructurings of the labour process. These are systemic occurrences, based in class struggles around the extension of management control of every part of work, and replacing workers with machinery; it must then be seen in the context of a history of Taylorism, Fordism and neo-Fordism, and their local expressions, such as racial Fordism in South Africa. The roll-out and the socio-economic effects of the 4IR are therefore shaped by inequality and power, and look to be dire for the working-class in a South Africa that already has record unemployment rates. In the local banking sector, the 4IR has been associated with a wave of retrenchments and branch closures. Faced with this situation, the South African Society of Bank Officials (SASBO), the biggest and oldest union in the finance sector, then with around 73 000 members, tried to hold a mass strike in late 2019. Blocked by the Labour Court, this would have been the union’s biggest strike in a century. It followed from a longer campaign by SASBO to halt job losses, ensure redeployment and reskilling for affected bank workers, and win an agreement for these aims with the banks. The union undertook research on the 4IR and sought to win support from banks, as well as government departments and other unions, for an alternative, worker-friendly roll-out of the 4IR. The decision to strike took place after extensive engagements with banks and stakeholders like government failed, the banks proceeding with retrenchments: the union faced an unprecedented challenge and was on the defensive. This dissertation maps SASBO’s campaign around the 4IR, using the Power Resources Approach (PRA), and assesses its approach. It also tries to show how an analysis of a moderate, older white-collar union like SASBO enriches South African labour studies. A qualitative methodology was used in this research to understand the issue at hand, using documents and semi-structured interviews with SASBO National Executive Committee members. The key findings are that the 4IR will not spare white-collar jobs and presents an unprecedented challenge to unions. There is an urgent need for union revitalisation, including new ways to organise effective responses to technological change. , Thesis (MA) -- Faculty of Humanities, Sociology, 2022
- Full Text:
- Authors: Moyo, Wisdom Ntandoyenkosi
- Date: 2022-10-14
- Subjects: Industry 4.0 , Fourth Industrial Revolution , Banks and banking South Africa , SASBO , Labor unions South Africa , Strikes and lockouts Bank employees South Africa , Working class South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406774 , vital:70306
- Description: The Fourth Industrial Revolution (4IR) is a global phenomenon, affecting workers and trade unions worldwide with the increased automation, including digitisation, of work. Although the 4IR has often been presented as an impersonal technological force that society must just accept, it is in fact rooted in the evolution of capitalist society: it is the latest in a series of industrial revolutions and restructurings of the labour process. These are systemic occurrences, based in class struggles around the extension of management control of every part of work, and replacing workers with machinery; it must then be seen in the context of a history of Taylorism, Fordism and neo-Fordism, and their local expressions, such as racial Fordism in South Africa. The roll-out and the socio-economic effects of the 4IR are therefore shaped by inequality and power, and look to be dire for the working-class in a South Africa that already has record unemployment rates. In the local banking sector, the 4IR has been associated with a wave of retrenchments and branch closures. Faced with this situation, the South African Society of Bank Officials (SASBO), the biggest and oldest union in the finance sector, then with around 73 000 members, tried to hold a mass strike in late 2019. Blocked by the Labour Court, this would have been the union’s biggest strike in a century. It followed from a longer campaign by SASBO to halt job losses, ensure redeployment and reskilling for affected bank workers, and win an agreement for these aims with the banks. The union undertook research on the 4IR and sought to win support from banks, as well as government departments and other unions, for an alternative, worker-friendly roll-out of the 4IR. The decision to strike took place after extensive engagements with banks and stakeholders like government failed, the banks proceeding with retrenchments: the union faced an unprecedented challenge and was on the defensive. This dissertation maps SASBO’s campaign around the 4IR, using the Power Resources Approach (PRA), and assesses its approach. It also tries to show how an analysis of a moderate, older white-collar union like SASBO enriches South African labour studies. A qualitative methodology was used in this research to understand the issue at hand, using documents and semi-structured interviews with SASBO National Executive Committee members. The key findings are that the 4IR will not spare white-collar jobs and presents an unprecedented challenge to unions. There is an urgent need for union revitalisation, including new ways to organise effective responses to technological change. , Thesis (MA) -- Faculty of Humanities, Sociology, 2022
- Full Text:
The regeneration of palmiet (prionium serratum) following hydrogeomorphic disturbance: a case study of the Kromme River wetland
- Authors: Van Eck, Caydon Daniël
- Date: 2022-10-14
- Subjects: Biogeomorphology South Africa Kromme Estuary (Eastern Cape) , Wetland ecology , Prionium serratum Regeneration , Fluvial geomorphology , River channels
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365555 , vital:65759
- Description: The Kromme River wetland in the Eastern Cape of South Africa occupies a broad valley (up to 350 m wide) with a gentle longitudinal slope of less than 2 % that has been formed by cut-and-fill cycles that are initiated by trunk-tributary interactions. These hydrogeomorphic disturbance events trigger gully erosion and generate sediments, the coarse fraction of which is deposited less than 2 km downstream, leading to depositional floodout features that fill gullies headwards. This process has been occurring at intervals for at least 10 000 years, and as such pre-dates the introduction of European farming practices in the area. Plants that regenerate by colonising these features are thought to have evolved adaptions necessary to colonise intermittently produced bare sandy sediments. This study aimed to examine the regeneration ecology of palmiet (Prionium serratum), the dominant vegetation community within these cut-and-fill wetlands, by relating its regeneration characteristics to environmental factors in a reach of the Kromme River wetland that has experienced a recent hydrogeomorphic disturbance event (approximately 10 years before the commencement of this study). Palmiet was found to be regenerating on sedimentary deposits on beds of gullies and on depositional bars on the margins of gully beds. The large depositional floodout downstream of a large gully also favoured palmiet regeneration, where it was found to be regenerating along not only the active channel, but also along old abandoned flow paths and sometimes areas well elevated above the channel. The geomorphic features that favoured palmiet regeneration were characterised by coarse-grained sediments (mean particle size approximately 310 μm) with low organic matter content (0.61 %), a low depth to the water table and low elevation above the thalweg (mean depth to water table is approximately 0.6 m), and a relatively close distance to the thalweg (< 10 m). This understanding of palmiet’s regeneration characteristics was viewed in relation to existing literature on undisturbed palmiet wetland plant communities and its reported contribution to conditions that favour wetland formation through gully filling, which allowed for the creation of a conceptual model of palmiet regeneration, colonisation and long-term persistence. This model was based on the Fluvial Biogeomorphic Succession concept. It suggests that palmiet’s interaction with the hydrogeomorphic environment throughout the different stages of its life cycle results in self-organising biogeomorphic landforms. Over hundreds of years, the reciprocal interactions between palmiet, sediments and water, fills gullies and restores valley bottoms, ultimately leading to the formation of a wetland landform. It is further proposed that through continued accretion, the geomorphic wetland landscape becomes more and more disconnected from the hydrogeomorphic dynamics of the fluvial system, such that the prevailing conditions begin to favour fynbos establishment, which may outcompete palmiet. , Thesis (MSc) -- Faculty of Science, Geography, 2022
- Full Text:
- Authors: Van Eck, Caydon Daniël
- Date: 2022-10-14
- Subjects: Biogeomorphology South Africa Kromme Estuary (Eastern Cape) , Wetland ecology , Prionium serratum Regeneration , Fluvial geomorphology , River channels
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365555 , vital:65759
- Description: The Kromme River wetland in the Eastern Cape of South Africa occupies a broad valley (up to 350 m wide) with a gentle longitudinal slope of less than 2 % that has been formed by cut-and-fill cycles that are initiated by trunk-tributary interactions. These hydrogeomorphic disturbance events trigger gully erosion and generate sediments, the coarse fraction of which is deposited less than 2 km downstream, leading to depositional floodout features that fill gullies headwards. This process has been occurring at intervals for at least 10 000 years, and as such pre-dates the introduction of European farming practices in the area. Plants that regenerate by colonising these features are thought to have evolved adaptions necessary to colonise intermittently produced bare sandy sediments. This study aimed to examine the regeneration ecology of palmiet (Prionium serratum), the dominant vegetation community within these cut-and-fill wetlands, by relating its regeneration characteristics to environmental factors in a reach of the Kromme River wetland that has experienced a recent hydrogeomorphic disturbance event (approximately 10 years before the commencement of this study). Palmiet was found to be regenerating on sedimentary deposits on beds of gullies and on depositional bars on the margins of gully beds. The large depositional floodout downstream of a large gully also favoured palmiet regeneration, where it was found to be regenerating along not only the active channel, but also along old abandoned flow paths and sometimes areas well elevated above the channel. The geomorphic features that favoured palmiet regeneration were characterised by coarse-grained sediments (mean particle size approximately 310 μm) with low organic matter content (0.61 %), a low depth to the water table and low elevation above the thalweg (mean depth to water table is approximately 0.6 m), and a relatively close distance to the thalweg (< 10 m). This understanding of palmiet’s regeneration characteristics was viewed in relation to existing literature on undisturbed palmiet wetland plant communities and its reported contribution to conditions that favour wetland formation through gully filling, which allowed for the creation of a conceptual model of palmiet regeneration, colonisation and long-term persistence. This model was based on the Fluvial Biogeomorphic Succession concept. It suggests that palmiet’s interaction with the hydrogeomorphic environment throughout the different stages of its life cycle results in self-organising biogeomorphic landforms. Over hundreds of years, the reciprocal interactions between palmiet, sediments and water, fills gullies and restores valley bottoms, ultimately leading to the formation of a wetland landform. It is further proposed that through continued accretion, the geomorphic wetland landscape becomes more and more disconnected from the hydrogeomorphic dynamics of the fluvial system, such that the prevailing conditions begin to favour fynbos establishment, which may outcompete palmiet. , Thesis (MSc) -- Faculty of Science, Geography, 2022
- Full Text:
The use of simulators and artificial intelligence in leadership feedback
- Authors: Ntombana, Sixolile
- Date: 2022-10-14
- Subjects: Artificial intelligence , Leadership , Employees Rating of , Communication in industrial relations , Qualitative reasoning Technological innovations , Chatbots
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/357685 , vital:64767
- Description: Leadership is a key factor in team success. For leadership to succeed, leaders need to possess the requisite competencies that can facilitate their performance. Team skills is identified as a leadership competency that is prioritised and most sought after by leaders. This follows studies that confirm that team skills are vital for leadership and team success. For leadership to develop team skills, feedback must be provided. Feedback is identified as information that is provided by an observer on a particular performance. The role of feedback in leadership development serves the purposes of engagement and self-reflection and evaluation of a leader’s performance. In this light, feedback cannot be separated from leadership as it is an essential part of communication in a leadership context. The nature and source of feedback can affect how the feedback is received, as shown by studies that suggest that the effectiveness of feedback goes beyond the content or nature (good/bad feedback) of the feedback. This study looks at two feedback sources: humans and artificial intelligence (AI) using students as the population. Humans have been the traditional source in feedback provision. Thus, in a team setting peers provide feedback on their peers’ performances. Unprecedented technological advancements have seen the improvement of AI capabilities to being able to give feedback. This has made AI a feedback source. Following these developments, this research assessed the way in which humans and AI provide feedback and the way in which students react to feedback provided by humans and AI. The research used chatbot AI, a Skills Simulator Assessment, launched by Kotlyar (2018). Students registered for Management One at Rhodes University in 2021 were the population for this research. The research was comprised of two phases where in phase one they were assessed by the Skill Simulator Assessment and in phase two they were assessed by their peers. This research found that students are not averse to feedback from AI, although they prefer peer feedback. It was further found that peer feedback tends to be tainted by lenience, while AI is not affected by lenience. This finding marked a significant development of AI in feedback provision. , Thesis (MCom) -- Faculty of Commerce, Management, 2022
- Full Text:
- Authors: Ntombana, Sixolile
- Date: 2022-10-14
- Subjects: Artificial intelligence , Leadership , Employees Rating of , Communication in industrial relations , Qualitative reasoning Technological innovations , Chatbots
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/357685 , vital:64767
- Description: Leadership is a key factor in team success. For leadership to succeed, leaders need to possess the requisite competencies that can facilitate their performance. Team skills is identified as a leadership competency that is prioritised and most sought after by leaders. This follows studies that confirm that team skills are vital for leadership and team success. For leadership to develop team skills, feedback must be provided. Feedback is identified as information that is provided by an observer on a particular performance. The role of feedback in leadership development serves the purposes of engagement and self-reflection and evaluation of a leader’s performance. In this light, feedback cannot be separated from leadership as it is an essential part of communication in a leadership context. The nature and source of feedback can affect how the feedback is received, as shown by studies that suggest that the effectiveness of feedback goes beyond the content or nature (good/bad feedback) of the feedback. This study looks at two feedback sources: humans and artificial intelligence (AI) using students as the population. Humans have been the traditional source in feedback provision. Thus, in a team setting peers provide feedback on their peers’ performances. Unprecedented technological advancements have seen the improvement of AI capabilities to being able to give feedback. This has made AI a feedback source. Following these developments, this research assessed the way in which humans and AI provide feedback and the way in which students react to feedback provided by humans and AI. The research used chatbot AI, a Skills Simulator Assessment, launched by Kotlyar (2018). Students registered for Management One at Rhodes University in 2021 were the population for this research. The research was comprised of two phases where in phase one they were assessed by the Skill Simulator Assessment and in phase two they were assessed by their peers. This research found that students are not averse to feedback from AI, although they prefer peer feedback. It was further found that peer feedback tends to be tainted by lenience, while AI is not affected by lenience. This finding marked a significant development of AI in feedback provision. , Thesis (MCom) -- Faculty of Commerce, Management, 2022
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A biological assessment of the Cape knifejaw (Oplegnathus conwayi) an endemic South African teleost
- Authors: Foster, Ryan Matthew
- Date: 2021-10-29
- Subjects: Perciformes South Africa , Osteichthyes South Africa , Fisheries South Africa , Perciformes Growth , Perciformes Age , Perciformes Reproduction , Sampling Citizen participation , Cape knifejaw (Oplegnathus conwayi)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191057 , vital:45054
- Description: The South African spearfishery forms a small component of South Africa’s complex coastal fishery. Although the smallest, this fishery sector has the largest proportion of data deficient species, and as a consequence is poorly managed. Oplegnathus conwayi (Cape knifejaw) is an example of one of these species for which there is very little and outdated biological and ecological data. This species is among the top target species by recreational spearfishers in South Africa. This thesis aimed to improve our socio-ecological knowledge of the South African spearfishery through the collection of biological and Fishers’ Ecological Knowledge (FEK) information on Oplegnathus conwayi, and human dimension information on the South African spearfishery. Monthly biological samples were collected through routine sampling (spearfishing) and augmented by recreational spearfishers. A total of 254 fish were collected from the warm-temperate coastal zone (East London – Cape Agulhas), 28 from the sub-tropical zone (Durban – East London) and 23 from the cool-temperate zone (Cape Agulhas – Cape Point). The results indicated that Oplegnathus conwayi is a slow-growing species, with a maximum recorded age of 27 years. The population sex ratio was skewed, with males dominant in the population (1M:0.6F). The length- and age-frequency distributions were, however, similar for both sexes. No significant differences were observed between male and female growth (LRT, p > 0.05), with the overall population growth curve being best described as L(t) = 697.15(1-e-0.06(t-6.30)). Males matured at a slightly larger size than females, however, no significant differences were observed (LRT, p > 0.05). The length- and age- at-50% maturity was 330 mm (FL) and 5.73 years for the full population, respectively. Histological analyses showed that Oplegnathus conwayi are asynchronous spawners with a gonochoristic reproductive style. Macroscopic staging and gonadosomatic index results indicated a protracted spawning season for Oplegnathus conwayi, with a peak in spring. A survey was designed and disseminated to collect FEK on the biology and population status of Oplegnathus conwayi and human dimension information on South Africa’s spearfishery. A total of 103 survey responses were received, of which 94 were regarded as specialised (spearfishers who had greater experience, skill and avidity, and maintained spearfishing as an important component of their lifestyle) spearfishers. Based on the responses of the specialist spearfishers, the top four main species caught by spearfishers from this survey were Seriola lalandi (13.9%), Pachymetopon grande (11.7%), Oplegnathus conwayi (11.4%) and Sparodon durbanensis (11%), and the majority of respondents indicated that there had been no changes in abundance, size and catches of these species in the years that they had been spearfishing. Respondents indicated that Oplegnathus conwayi are most commonly targeted in the Eastern Cape and are found at depths of up to 40 m. Respondents also indicated that there may be a seasonal onshore (Summer/Winter) and offshore (Summer/Winter) migration with year-round spawning and a peak in November, December and January. The incorporation of spearfishers into the data collection, both through the collection of specimens and their FEK, was beneficial to this study. Besides providing samples from a broader geographical range than the primary collection area, the collaboration with spearfishers has promoted the inclusion of this group into the management system. The findings of this study also suggest that FEK data can be more reliable if the concept of recreational specialisation is incorporated into data collection. While the FEK suggested that the population was stable, a stock assessment is necessary to fully understand the population status and implement management strategies. Nevertheless, the key life history characteristics (slow growth and late maturation) observed in this study are characteristic of species that is vulnerable to overexploitation, and thus the precautionary approach should be applied. The reproductive information collected in this study has provided information for the implementation of an appropriate size limit regulation for Oplegnathus conwayi. Here, a minimum size limit of 400 mm TL, which corresponds approximately with the length-at-50% maturity of 330 mm FL, would be appropriate to allow fish to mature and spawn, and reduce the likelihood of recruitment overfishing. Reduction in the bag limit from five to two fish per person per day may also be appropriate as a precautionary measure until a stock assessment has been completed. Finally, the incorporation of stakeholder into biological collection and the use of FEK may be a useful approach for other data deficient species and in countries with limited resources for ecological research. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Authors: Foster, Ryan Matthew
- Date: 2021-10-29
- Subjects: Perciformes South Africa , Osteichthyes South Africa , Fisheries South Africa , Perciformes Growth , Perciformes Age , Perciformes Reproduction , Sampling Citizen participation , Cape knifejaw (Oplegnathus conwayi)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191057 , vital:45054
- Description: The South African spearfishery forms a small component of South Africa’s complex coastal fishery. Although the smallest, this fishery sector has the largest proportion of data deficient species, and as a consequence is poorly managed. Oplegnathus conwayi (Cape knifejaw) is an example of one of these species for which there is very little and outdated biological and ecological data. This species is among the top target species by recreational spearfishers in South Africa. This thesis aimed to improve our socio-ecological knowledge of the South African spearfishery through the collection of biological and Fishers’ Ecological Knowledge (FEK) information on Oplegnathus conwayi, and human dimension information on the South African spearfishery. Monthly biological samples were collected through routine sampling (spearfishing) and augmented by recreational spearfishers. A total of 254 fish were collected from the warm-temperate coastal zone (East London – Cape Agulhas), 28 from the sub-tropical zone (Durban – East London) and 23 from the cool-temperate zone (Cape Agulhas – Cape Point). The results indicated that Oplegnathus conwayi is a slow-growing species, with a maximum recorded age of 27 years. The population sex ratio was skewed, with males dominant in the population (1M:0.6F). The length- and age-frequency distributions were, however, similar for both sexes. No significant differences were observed between male and female growth (LRT, p > 0.05), with the overall population growth curve being best described as L(t) = 697.15(1-e-0.06(t-6.30)). Males matured at a slightly larger size than females, however, no significant differences were observed (LRT, p > 0.05). The length- and age- at-50% maturity was 330 mm (FL) and 5.73 years for the full population, respectively. Histological analyses showed that Oplegnathus conwayi are asynchronous spawners with a gonochoristic reproductive style. Macroscopic staging and gonadosomatic index results indicated a protracted spawning season for Oplegnathus conwayi, with a peak in spring. A survey was designed and disseminated to collect FEK on the biology and population status of Oplegnathus conwayi and human dimension information on South Africa’s spearfishery. A total of 103 survey responses were received, of which 94 were regarded as specialised (spearfishers who had greater experience, skill and avidity, and maintained spearfishing as an important component of their lifestyle) spearfishers. Based on the responses of the specialist spearfishers, the top four main species caught by spearfishers from this survey were Seriola lalandi (13.9%), Pachymetopon grande (11.7%), Oplegnathus conwayi (11.4%) and Sparodon durbanensis (11%), and the majority of respondents indicated that there had been no changes in abundance, size and catches of these species in the years that they had been spearfishing. Respondents indicated that Oplegnathus conwayi are most commonly targeted in the Eastern Cape and are found at depths of up to 40 m. Respondents also indicated that there may be a seasonal onshore (Summer/Winter) and offshore (Summer/Winter) migration with year-round spawning and a peak in November, December and January. The incorporation of spearfishers into the data collection, both through the collection of specimens and their FEK, was beneficial to this study. Besides providing samples from a broader geographical range than the primary collection area, the collaboration with spearfishers has promoted the inclusion of this group into the management system. The findings of this study also suggest that FEK data can be more reliable if the concept of recreational specialisation is incorporated into data collection. While the FEK suggested that the population was stable, a stock assessment is necessary to fully understand the population status and implement management strategies. Nevertheless, the key life history characteristics (slow growth and late maturation) observed in this study are characteristic of species that is vulnerable to overexploitation, and thus the precautionary approach should be applied. The reproductive information collected in this study has provided information for the implementation of an appropriate size limit regulation for Oplegnathus conwayi. Here, a minimum size limit of 400 mm TL, which corresponds approximately with the length-at-50% maturity of 330 mm FL, would be appropriate to allow fish to mature and spawn, and reduce the likelihood of recruitment overfishing. Reduction in the bag limit from five to two fish per person per day may also be appropriate as a precautionary measure until a stock assessment has been completed. Finally, the incorporation of stakeholder into biological collection and the use of FEK may be a useful approach for other data deficient species and in countries with limited resources for ecological research. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
Generation news: Consuming, sharing, and producing news across generations in five Johannesburg households
- Authors: Silber, Gerson Russel
- Date: 2021-10-29
- Subjects: Baby boom generation South Africa , Generation Y South Africa , Conflict of generations South Africa Johannesburg , Generations South Africa Johannesburg , Digital media South Africa , Social media and journalism South Africa , Digital media Social aspects South Africa , News audiences South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192342 , vital:45217
- Description: This study sets out to explore the meaning, extent, and impact of the generational divide, between so-called Baby Boomers and their Millennial offspring, on the way news is accessed, consumed, shared, and produced in five purposively selected households in the Johannesburg area. Aside from these widely-used generational identifiers, Baby Boomers and Millennials are also commonly referred to as Digital Immigrants and Digital Natives, respectively. However, in a world where smartphones have become commonplace, and internet connectivity via fixed broadband and mobile data is ubiquitous, it can be argued that digital technologies now serve as a link, or perhaps even a bridge, between younger and older generations living in the same household. The study aims to put this proposition to the test, by interrogating the role of news as a conduit for storytelling and information-sharing in environments where each occupant will typically be using their own devices, with a wide variety of personally-curated news sources and platforms at their fingertips. This fragmentation or individualisation of access to news stands in sharp contrast to the communal traditions of the pre-Internet era, during which families would gather around the TV set to watch the evening newscast, or share sections of the Sunday newspaper according to their age and interest. This research, which seeks to address a gap in the literature of research into intra-generational news consumption in family households in the digital era, identifies points of intersection as well as diversion in media usage habits. An example of the former is the prevalence of WhatsApp as a centralised "meeting-point" for the sharing of useful, hyper-localised information within the family group, and beyond that, as a cross-generational news and discussion platform in its own right. On the opposite end of the spectrum, the study explores strict and seemingly counterintuitive divides between the generations, with some Millennial respondents rejecting social media platforms as "pointless and invasive, and some Baby Boomer parents embracing the platforms as forums for free expression and networking. In line with the key research question, which seeks to identify and analyse news usage and consumption across the generations in a selection of family households, the study considers the ways in which families in the digital era are creating a culture of shared interests and the active sharing of news, breaching the boundaries of their private spaces in a microcosm of the Habermasian public sphere of discourse and opinion. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Authors: Silber, Gerson Russel
- Date: 2021-10-29
- Subjects: Baby boom generation South Africa , Generation Y South Africa , Conflict of generations South Africa Johannesburg , Generations South Africa Johannesburg , Digital media South Africa , Social media and journalism South Africa , Digital media Social aspects South Africa , News audiences South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192342 , vital:45217
- Description: This study sets out to explore the meaning, extent, and impact of the generational divide, between so-called Baby Boomers and their Millennial offspring, on the way news is accessed, consumed, shared, and produced in five purposively selected households in the Johannesburg area. Aside from these widely-used generational identifiers, Baby Boomers and Millennials are also commonly referred to as Digital Immigrants and Digital Natives, respectively. However, in a world where smartphones have become commonplace, and internet connectivity via fixed broadband and mobile data is ubiquitous, it can be argued that digital technologies now serve as a link, or perhaps even a bridge, between younger and older generations living in the same household. The study aims to put this proposition to the test, by interrogating the role of news as a conduit for storytelling and information-sharing in environments where each occupant will typically be using their own devices, with a wide variety of personally-curated news sources and platforms at their fingertips. This fragmentation or individualisation of access to news stands in sharp contrast to the communal traditions of the pre-Internet era, during which families would gather around the TV set to watch the evening newscast, or share sections of the Sunday newspaper according to their age and interest. This research, which seeks to address a gap in the literature of research into intra-generational news consumption in family households in the digital era, identifies points of intersection as well as diversion in media usage habits. An example of the former is the prevalence of WhatsApp as a centralised "meeting-point" for the sharing of useful, hyper-localised information within the family group, and beyond that, as a cross-generational news and discussion platform in its own right. On the opposite end of the spectrum, the study explores strict and seemingly counterintuitive divides between the generations, with some Millennial respondents rejecting social media platforms as "pointless and invasive, and some Baby Boomer parents embracing the platforms as forums for free expression and networking. In line with the key research question, which seeks to identify and analyse news usage and consumption across the generations in a selection of family households, the study considers the ways in which families in the digital era are creating a culture of shared interests and the active sharing of news, breaching the boundaries of their private spaces in a microcosm of the Habermasian public sphere of discourse and opinion. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
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