An insight into the profile characteristics and technical batting skill of adolescent cricket players
- Authors: Clark, Matthew Edward
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2838 , vital:20331
- Description: Background: Current traditional cricket practices incorporate the use of a netted-off pitch to provide cricket players the opportunity to hone their skills with bat and ball. The lack of ecological validity of these training environments results in the absence of important task and environmental constraints which influences the manner in which the sport is played. Objectives: The purpose of the current research was two-fold: firstly, it aimed to establish a profile database of adolescent cricket players in the Eastern Cape province of South Africa; and secondly, it aimed to investigate the efficacy of a constraints-led training intervention on skill development in adolescent cricket batsmen. Methods: Study I required 90 participants (u13: n = 40; u15: n = 50) to perform measures pertaining to anthropometric, morphological, flexibility and physical performance characteristics. This included stature, mass, body composition, limb length, flexibility, agility, and power measures. Study II was a case-control study (u15: n = 24), whereby the experimental group (n = 12) was exposed to a constraints-led batting protocol during the course of the cricket season. The objective of the protocol was to encourage the manipulation of the ball around the playing field. Pre- and post-intervention measures were performed using a batting skills test, which assessed batsmen’s capability to manipulate the ball to various areas of the playing field. Results: Study I revealed significant differences (p <0.0001) in stature, mass, limb length and power variables when comparing the u15 age group with the u13 age group. No differences were recorded for agility. The u13 age group had greater linear correlations for the variables of interest compared to the u15 age group. Study II revealed no differences in technical skill between the experimental group and the control (p <0.315).. The tests also revealed that adolescent batsmen favoured hitting deliveries through the extra-cover scoring zone. The third-man and fine-leg scoring zones were least preferred to hit deliveries through. A number of limitations to the study design resulted in the inability to determine the efficacy of a constraints-led batting protocol on skill development in an adolescent batting cohort. Conclusion: The results of study I indicated that the onset of puberty played an important role in the measures and performances between the u13 and u15 age groups. The results of study II indicated that adolescent batsmen are not adept at manipulating the ball around the field. Recommendations are provided for both studies.
- Full Text:
- Authors: Clark, Matthew Edward
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2838 , vital:20331
- Description: Background: Current traditional cricket practices incorporate the use of a netted-off pitch to provide cricket players the opportunity to hone their skills with bat and ball. The lack of ecological validity of these training environments results in the absence of important task and environmental constraints which influences the manner in which the sport is played. Objectives: The purpose of the current research was two-fold: firstly, it aimed to establish a profile database of adolescent cricket players in the Eastern Cape province of South Africa; and secondly, it aimed to investigate the efficacy of a constraints-led training intervention on skill development in adolescent cricket batsmen. Methods: Study I required 90 participants (u13: n = 40; u15: n = 50) to perform measures pertaining to anthropometric, morphological, flexibility and physical performance characteristics. This included stature, mass, body composition, limb length, flexibility, agility, and power measures. Study II was a case-control study (u15: n = 24), whereby the experimental group (n = 12) was exposed to a constraints-led batting protocol during the course of the cricket season. The objective of the protocol was to encourage the manipulation of the ball around the playing field. Pre- and post-intervention measures were performed using a batting skills test, which assessed batsmen’s capability to manipulate the ball to various areas of the playing field. Results: Study I revealed significant differences (p <0.0001) in stature, mass, limb length and power variables when comparing the u15 age group with the u13 age group. No differences were recorded for agility. The u13 age group had greater linear correlations for the variables of interest compared to the u15 age group. Study II revealed no differences in technical skill between the experimental group and the control (p <0.315).. The tests also revealed that adolescent batsmen favoured hitting deliveries through the extra-cover scoring zone. The third-man and fine-leg scoring zones were least preferred to hit deliveries through. A number of limitations to the study design resulted in the inability to determine the efficacy of a constraints-led batting protocol on skill development in an adolescent batting cohort. Conclusion: The results of study I indicated that the onset of puberty played an important role in the measures and performances between the u13 and u15 age groups. The results of study II indicated that adolescent batsmen are not adept at manipulating the ball around the field. Recommendations are provided for both studies.
- Full Text:
An investigation into how Grade 10 Physical Sciences learners make sense of resultant vectors
- Authors: Motsilili, Tshepo Elliot
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1407 , vital:20054
- Description: The focus of this study was on how Grade 10 Physical Sciences learners make sense of resultant vectors. During my experience over more than 10 years as a Science teacher in Matatiele in the Eastern Cape Province I found that Grade 10 Physical Sciences learners consistently struggled to work with resultant vectors. Many studies have shown that learners in similar contexts are generally not doing well in Science. An interpretive paradigm was used in this study, focusing on the individual or a specific group in a qualitative case study approach and a social constructivist perspective. The unit of analysis was on how Grade 10 Physical Sciences learners make sense of resultant vectors. A diagnostic test, observation and videotaped lessons, learners’ workbooks, summative test and stimulated recall interviews were used to gather data. The data were analysed inductively using a thematic approach and in relation to the main research question: How do Grade 10 Physical Sciences learners make sense of resultant vectors? The data were validated through watching the videotaped lessons with the teacher who had been observed teaching vectors. Also, transcripts of the interviews and a summary of discussions were given back to the teacher whose learners had been observed to verify the learners’ responses and check for any misconceptions. It was found that linking scientific concepts to learners’ prior knowledge enabled them to learn in a relaxed and non-threatening environment. In doing so, sense making of resultant vectors was possible. The study thus recommends that teachers should be supported in their endeavours to help learners make sense of scientific concepts during teaching and learning situations. Some language related challenges that were also encountered warrant further research.
- Full Text:
- Authors: Motsilili, Tshepo Elliot
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1407 , vital:20054
- Description: The focus of this study was on how Grade 10 Physical Sciences learners make sense of resultant vectors. During my experience over more than 10 years as a Science teacher in Matatiele in the Eastern Cape Province I found that Grade 10 Physical Sciences learners consistently struggled to work with resultant vectors. Many studies have shown that learners in similar contexts are generally not doing well in Science. An interpretive paradigm was used in this study, focusing on the individual or a specific group in a qualitative case study approach and a social constructivist perspective. The unit of analysis was on how Grade 10 Physical Sciences learners make sense of resultant vectors. A diagnostic test, observation and videotaped lessons, learners’ workbooks, summative test and stimulated recall interviews were used to gather data. The data were analysed inductively using a thematic approach and in relation to the main research question: How do Grade 10 Physical Sciences learners make sense of resultant vectors? The data were validated through watching the videotaped lessons with the teacher who had been observed teaching vectors. Also, transcripts of the interviews and a summary of discussions were given back to the teacher whose learners had been observed to verify the learners’ responses and check for any misconceptions. It was found that linking scientific concepts to learners’ prior knowledge enabled them to learn in a relaxed and non-threatening environment. In doing so, sense making of resultant vectors was possible. The study thus recommends that teachers should be supported in their endeavours to help learners make sense of scientific concepts during teaching and learning situations. Some language related challenges that were also encountered warrant further research.
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An investigation into how Grade 8 Natural Sciences learners make sense of chemical reactions during lessons involving familiar resources: a case study
- Authors: Mashozhera, Farasten
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1374 , vital:20051
- Description: My experience of working with science learners for the past 25 years and witnessing their difficulty in comprehending chemical reactions motivated me to investigate how learners make sense of chemical reactions in lessons involving the use of familiar resources. Essentially, this study sought to gain insights into whether engaging learners during practical activities using familiar resources facilitated meaning-making of chemical reactions. There is not much literature on early high school learning of concepts linked to chemical reactions which opened the way for this research. This study was conducted at a public high school comprised of Grades 8-12 (FET band) in Grahamstown in the Eastern Cape, South Africa. It is located within the interpretive paradigm. Within this paradigm, both quantitative and qualitative methods were conducted with a Grade 8 Natural Sciences class. Data sets were analysed in relation to the research questions. A variety of data gathering techniques were used, namely diagnostic and summative tests, worksheets and a semistructured interview with a focus group. Both inductive and deductive processes were applied during the data analysis process. The validation process was done through data analysis using mixed methods (quantitative and qualitative), checking transcriptions with the focus group and the use of a research participant. Learners in the focus group verified their responses, checking for any misrepresentations. The main finding of this study is that the use of practical activities, using familiar resources, facilitated learner engagement and meaningful learning. However, this study further revealed that some concepts associated with chemical reactions were challenging to learners. Similarly, that some prior everyday knowledge and experiences that learners bring to the science classroom impede sense-making in Natural Sciences. In addition, the language of learning and teaching (LoLT) and the language of science are other factors impeding sense-making of scientific concepts. It is thus recommended that teachers plan well in order to incorporate the use of practical activities using familiar resources during mediation of learning.
- Full Text:
- Authors: Mashozhera, Farasten
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1374 , vital:20051
- Description: My experience of working with science learners for the past 25 years and witnessing their difficulty in comprehending chemical reactions motivated me to investigate how learners make sense of chemical reactions in lessons involving the use of familiar resources. Essentially, this study sought to gain insights into whether engaging learners during practical activities using familiar resources facilitated meaning-making of chemical reactions. There is not much literature on early high school learning of concepts linked to chemical reactions which opened the way for this research. This study was conducted at a public high school comprised of Grades 8-12 (FET band) in Grahamstown in the Eastern Cape, South Africa. It is located within the interpretive paradigm. Within this paradigm, both quantitative and qualitative methods were conducted with a Grade 8 Natural Sciences class. Data sets were analysed in relation to the research questions. A variety of data gathering techniques were used, namely diagnostic and summative tests, worksheets and a semistructured interview with a focus group. Both inductive and deductive processes were applied during the data analysis process. The validation process was done through data analysis using mixed methods (quantitative and qualitative), checking transcriptions with the focus group and the use of a research participant. Learners in the focus group verified their responses, checking for any misrepresentations. The main finding of this study is that the use of practical activities, using familiar resources, facilitated learner engagement and meaningful learning. However, this study further revealed that some concepts associated with chemical reactions were challenging to learners. Similarly, that some prior everyday knowledge and experiences that learners bring to the science classroom impede sense-making in Natural Sciences. In addition, the language of learning and teaching (LoLT) and the language of science are other factors impeding sense-making of scientific concepts. It is thus recommended that teachers plan well in order to incorporate the use of practical activities using familiar resources during mediation of learning.
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An investigation into how participation in science expo projects influences grade 9 learners’ dispositions towards science learning: a case study
- Authors: Musekiwa, Beatrice K
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1430 , vital:20056
- Description: There has been increasing participation of learners from disadvantaged backgrounds in competitive events like the Eskom Science Expo over the past few years. It is against this backdrop that this study sought to find out how some grade 9 learners’ participation in science expo projects influences their disposition towards science. In the context of this study, disposition refers to how learners view themselves in relation to science learning as a result of participating in science expos. The study is underpinned by an interpretative paradigm and I made use of a qualitative case study. My research participants were five grade 9 learners from two secondary schools in Grahamstown in the Eastern Cape Province of South Africa. I used observations, semistructured interviews and learners’ journals for my data collection. To analyse the data I used the inductive approach where I made use of themes emerging from the data. The social learning theory described by Vygotsky (1978) is the guiding theory in the research with a focus on mediation of learning and the zone of proximal development (ZPD). The main findings from my study were that indeed participation in science expos does influence the disposition of learners towards science among the grade 9 learners. I also found an improved understanding of scientific concepts as the learners interacted with science in everyday and familiar contexts. Lastly, doing projects that are close to learners’ interests resulted in them enjoying doing science more. The learners’ science expo projects contribution to the Grahamstown community is of no small value, as has already been seen by the achievement of previous participants. The current group is already showing their impact and influence of the science–expo project involvement in terms of their performance in their classrooms and in their awareness of their role as young ‘scientists’. I therefore recommend that more learners be encouraged to take part in such projects as the science-expo projects not only improve learners’ understanding of the subject matter but also encourages a positive shift in their attitude towards science learning. It also enhances their understanding by allowing the young learners to interact with their environment to find solutions to problems that the community might be faced with, for example, water shortages and sustainable development initiations like gardening and the proper use of naturally acquired water resources.
- Full Text:
- Authors: Musekiwa, Beatrice K
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/1430 , vital:20056
- Description: There has been increasing participation of learners from disadvantaged backgrounds in competitive events like the Eskom Science Expo over the past few years. It is against this backdrop that this study sought to find out how some grade 9 learners’ participation in science expo projects influences their disposition towards science. In the context of this study, disposition refers to how learners view themselves in relation to science learning as a result of participating in science expos. The study is underpinned by an interpretative paradigm and I made use of a qualitative case study. My research participants were five grade 9 learners from two secondary schools in Grahamstown in the Eastern Cape Province of South Africa. I used observations, semistructured interviews and learners’ journals for my data collection. To analyse the data I used the inductive approach where I made use of themes emerging from the data. The social learning theory described by Vygotsky (1978) is the guiding theory in the research with a focus on mediation of learning and the zone of proximal development (ZPD). The main findings from my study were that indeed participation in science expos does influence the disposition of learners towards science among the grade 9 learners. I also found an improved understanding of scientific concepts as the learners interacted with science in everyday and familiar contexts. Lastly, doing projects that are close to learners’ interests resulted in them enjoying doing science more. The learners’ science expo projects contribution to the Grahamstown community is of no small value, as has already been seen by the achievement of previous participants. The current group is already showing their impact and influence of the science–expo project involvement in terms of their performance in their classrooms and in their awareness of their role as young ‘scientists’. I therefore recommend that more learners be encouraged to take part in such projects as the science-expo projects not only improve learners’ understanding of the subject matter but also encourages a positive shift in their attitude towards science learning. It also enhances their understanding by allowing the young learners to interact with their environment to find solutions to problems that the community might be faced with, for example, water shortages and sustainable development initiations like gardening and the proper use of naturally acquired water resources.
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An investigation into the discursive contructions of childhood masculinity and femininity in BEN 10
- Authors: Gharbaharan, Leah
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3384 , vital:20477
- Description: This thesis investigates the representation of gendered childhood in popular children’s television series Ben 10. The series focuses on ten year old Ben who is granted alien powers, deciding to use them to protect innocent people from danger. Alongside Ben is his ten year old female cousin, Gwen, presented as his foil and guide throughout the series. As the characters develop the series presents particular gendered ways of performing childhood and adolescence and responses to the challenges of growing up. Before charting the trajectories of masculinity and femininity of the series I provide a theoretical framework drawing on the work of Foucault for his conceptualisation of discourse, discursive regimes and discursive subjects. The discursive approach is further explored by outlining particular concepts posited by Connell and Butler who argue for the discursive construction and performativity of gender. Similarly, I employ a social constructionist approach to childhood, arguing for children as active meaning makers – albeit constrained by broader discourses. They are constantly learning behaviours which shape their social practice, indicating the significance of studies on children’s media. Consistent with a constructivist approach, this study employs a qualitative methodology to undertake a Critical Discourse Analysis of select episodes, also informed by narrative theories. These ideas underpin the textual analysis of each purposively sampled episode of the three series to present the progression of masculinity and femininity from childhood through early and later adolescence through the characters Ben and Gwen. The analysis serves to demonstrate that Rousseau’s gendered notions of childhood still have considerable purchase in the twenty-first century, particularly in relation to the female character. This study’s findings propose a shift in children’s televisual representations to espousing more liberal views of masculinity, wherein boys are permitted space to feel fear and anxiety. Unsurprisingly, the series continues to uphold traditional ideals of heteronormativity and a hegemonic masculinity which uses physicality to demonstrate dominance. Furthermore, despite the modern conception of self-actualising females the series expects its female characters to work doubly hard without fundamentally challenging patriarchal ideals. That conventional, patriarchal gender roles are rehearsed and privileged in this popular series has implications in terms of persistent gender inequalities.
- Full Text:
- Authors: Gharbaharan, Leah
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3384 , vital:20477
- Description: This thesis investigates the representation of gendered childhood in popular children’s television series Ben 10. The series focuses on ten year old Ben who is granted alien powers, deciding to use them to protect innocent people from danger. Alongside Ben is his ten year old female cousin, Gwen, presented as his foil and guide throughout the series. As the characters develop the series presents particular gendered ways of performing childhood and adolescence and responses to the challenges of growing up. Before charting the trajectories of masculinity and femininity of the series I provide a theoretical framework drawing on the work of Foucault for his conceptualisation of discourse, discursive regimes and discursive subjects. The discursive approach is further explored by outlining particular concepts posited by Connell and Butler who argue for the discursive construction and performativity of gender. Similarly, I employ a social constructionist approach to childhood, arguing for children as active meaning makers – albeit constrained by broader discourses. They are constantly learning behaviours which shape their social practice, indicating the significance of studies on children’s media. Consistent with a constructivist approach, this study employs a qualitative methodology to undertake a Critical Discourse Analysis of select episodes, also informed by narrative theories. These ideas underpin the textual analysis of each purposively sampled episode of the three series to present the progression of masculinity and femininity from childhood through early and later adolescence through the characters Ben and Gwen. The analysis serves to demonstrate that Rousseau’s gendered notions of childhood still have considerable purchase in the twenty-first century, particularly in relation to the female character. This study’s findings propose a shift in children’s televisual representations to espousing more liberal views of masculinity, wherein boys are permitted space to feel fear and anxiety. Unsurprisingly, the series continues to uphold traditional ideals of heteronormativity and a hegemonic masculinity which uses physicality to demonstrate dominance. Furthermore, despite the modern conception of self-actualising females the series expects its female characters to work doubly hard without fundamentally challenging patriarchal ideals. That conventional, patriarchal gender roles are rehearsed and privileged in this popular series has implications in terms of persistent gender inequalities.
- Full Text:
An investigation into the interaction effects of simultaneous physical and cognitive task execution on performance, perceptual and physical responses
- Authors: Ross, Natalie
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3562 , vital:20525
- Description: Many modern day work environments require some degree of dual tasking, particularly the simultaneous performance of cognitive jobs alongside physical activity. The nature of such tasks is often job dependent and may require cognitive functions such as perception, decision making, memory, or response selection/execution in conjunction to task specific physical requirements. Previous research has indicated a possible relationship between concurrent physical and cognitive demands and task performance, safety and efficiency. However, this research is limited and inconsistent. The current study aimed to identify the interaction, if any, between concurrent physical and mental demands, and determine the impact of sensory modality and stage of information processing on this interaction, with specific focus on the performance, perceptual and physical responses during different types of cognitive tasks performed concurrently with a lifting task. 20 (10 male, 10 female) Rhodes University students participated in this study. Each participant performed 9 test conditions - a physical lifting task, a visual and an auditory memory task, and a visual and an auditory decision making task in isolation, as well as the lifting task concurrently with each of these cognitive tasks. Performance was recorded via accuracy and work output of cognitive tasks and the number of lifts for each condition. Perceptual measures were obtained via the Borg RPE and Subjective Workload Assessment Technique. Spinal kinematics were measured using the Lumbar Motion Monitor, while muscle activity of the Erector Spinae, Rectus Abdominis, Rectus Femoris and Biceps Femoris muscles were recorded using the Biometrix Data Logger surface EMG equipment. Mean results were analysed using a dependent T-test to observe any general interaction, and a Two-way ANOVA for the impact of sensory modality and stage of processing. Individual responses were also considered to gain better understanding of both intra and inter-human variability under the various test conditions. Results showed a significant decrease in cognitive performance, increased perception of physical effort, time pressure, mental effort and psychological stress under simultaneous physical and mental demands, while no significant differences in physical responses were observed. Further observations included increased dual-task interference during visual and decision-making tasks when combined with physical demands compared to that of auditory and memory tasks respectively. Individual responses showed large variability between individuals indicating the presence of positive, negative and non-responders to concurrent physical and mental demands. Results therefore imply an individual specific interaction between concurrent physical and mental demands that may or may not be detrimental to worker productivity, job error, injury rates and worker well-being, and that the type of cognitive task performed may impact this interaction.
- Full Text:
- Authors: Ross, Natalie
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3562 , vital:20525
- Description: Many modern day work environments require some degree of dual tasking, particularly the simultaneous performance of cognitive jobs alongside physical activity. The nature of such tasks is often job dependent and may require cognitive functions such as perception, decision making, memory, or response selection/execution in conjunction to task specific physical requirements. Previous research has indicated a possible relationship between concurrent physical and cognitive demands and task performance, safety and efficiency. However, this research is limited and inconsistent. The current study aimed to identify the interaction, if any, between concurrent physical and mental demands, and determine the impact of sensory modality and stage of information processing on this interaction, with specific focus on the performance, perceptual and physical responses during different types of cognitive tasks performed concurrently with a lifting task. 20 (10 male, 10 female) Rhodes University students participated in this study. Each participant performed 9 test conditions - a physical lifting task, a visual and an auditory memory task, and a visual and an auditory decision making task in isolation, as well as the lifting task concurrently with each of these cognitive tasks. Performance was recorded via accuracy and work output of cognitive tasks and the number of lifts for each condition. Perceptual measures were obtained via the Borg RPE and Subjective Workload Assessment Technique. Spinal kinematics were measured using the Lumbar Motion Monitor, while muscle activity of the Erector Spinae, Rectus Abdominis, Rectus Femoris and Biceps Femoris muscles were recorded using the Biometrix Data Logger surface EMG equipment. Mean results were analysed using a dependent T-test to observe any general interaction, and a Two-way ANOVA for the impact of sensory modality and stage of processing. Individual responses were also considered to gain better understanding of both intra and inter-human variability under the various test conditions. Results showed a significant decrease in cognitive performance, increased perception of physical effort, time pressure, mental effort and psychological stress under simultaneous physical and mental demands, while no significant differences in physical responses were observed. Further observations included increased dual-task interference during visual and decision-making tasks when combined with physical demands compared to that of auditory and memory tasks respectively. Individual responses showed large variability between individuals indicating the presence of positive, negative and non-responders to concurrent physical and mental demands. Results therefore imply an individual specific interaction between concurrent physical and mental demands that may or may not be detrimental to worker productivity, job error, injury rates and worker well-being, and that the type of cognitive task performed may impact this interaction.
- Full Text:
An investigation into the prevalence and growth of phishing attacks against South African financial targets
- Authors: Lala, Darshan Magan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3157 , vital:20379
- Description: Phishing in the electronic communications medium is the act of sending unsolicited email messages with the intention of masquerading as a reputed business. The objective is to deceive the recipient into divulging personal and sensitive information such as bank account details, credit card numbers and passwords. Attacks against financial services are the most common types of targets for scammers. Phishing attacks in South Africa have cost businesses and consumers substantial amounts of financial loss. This research investigated existing literature to understand the basic concepts of email, phishing, spam and how these fit together. The research also looks into the increasing growth of phishing worldwide and in particular against South African targets. A quantitative study is performed and reported on; this involves the study and analysis of phishing statistics in a data set provided by the South African Anti-Phishing Working Group. The data set contains phishing URL information, country code where the site has been hosted, targeted company name, IP address information and timestamp of the phishing site. The data set contains 161 different phishing targets. The research primarily focuses on the trend in phishing attacks against six South African based financial institutions, but also correlates this with the overall global trend using statistical analysis. The results from the study of the data set are compared to existing statistics and literature regarding the prevalence and growth of phishing in South Africa. The question that this research answers is whether or not the prevalence and growth of phishing in South Africa correlates with the global trend in phishing attacks. The findings indicate that certain correlations exist between some of the South African phishing targets and global phishing trends.
- Full Text:
- Authors: Lala, Darshan Magan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3157 , vital:20379
- Description: Phishing in the electronic communications medium is the act of sending unsolicited email messages with the intention of masquerading as a reputed business. The objective is to deceive the recipient into divulging personal and sensitive information such as bank account details, credit card numbers and passwords. Attacks against financial services are the most common types of targets for scammers. Phishing attacks in South Africa have cost businesses and consumers substantial amounts of financial loss. This research investigated existing literature to understand the basic concepts of email, phishing, spam and how these fit together. The research also looks into the increasing growth of phishing worldwide and in particular against South African targets. A quantitative study is performed and reported on; this involves the study and analysis of phishing statistics in a data set provided by the South African Anti-Phishing Working Group. The data set contains phishing URL information, country code where the site has been hosted, targeted company name, IP address information and timestamp of the phishing site. The data set contains 161 different phishing targets. The research primarily focuses on the trend in phishing attacks against six South African based financial institutions, but also correlates this with the overall global trend using statistical analysis. The results from the study of the data set are compared to existing statistics and literature regarding the prevalence and growth of phishing in South Africa. The question that this research answers is whether or not the prevalence and growth of phishing in South Africa correlates with the global trend in phishing attacks. The findings indicate that certain correlations exist between some of the South African phishing targets and global phishing trends.
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An investigation into the survival strategies of the rural elderly in Zimbabwe: a case study of Hobodo ward in Mangwe District in Zimbabwe
- Authors: Marazi, Tafara
- Date: 2016
- Subjects: Rural elderly -- Zimbabwe , Elderly poor -- Zimbabwe , Ophans -- Services for -- Zimbabwe , AIDS (Disease) -- Zimbabwe , Child welfare -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3407 , http://hdl.handle.net/10962/d1020605
- Description: The thesis focuses on the survival mechanisms of the rural poor elderly in Zimbabwe. The situation of the rural elderly is looked at in the context of the ravaging HIV/AIDS pandemic. The focus is specifically directed on the increasing numbers of orphans who are generated following the rampant deaths of their parents (sexually active individuals). With Africa failing to effectively withstand the forcefulness of the pandemic, the community structures in Zimbabwe are being heavily shaken to the detriment of all social groups. It is within this continuum that the research is laid out to investigate the situation on the ground. In this case, a fieldwork exercise was carried out in the Hobodo ward of Mangwe district in Zimbabwe. An intensive and in-depth examination of the critical situation was pursued under the case study model. To make the study more focused, the elderly were placed under investigation with regards to their new role of providing familial care for the orphans. The manner in which they face such a towering task under strained resources and limited knowhow was explored. The well-being of the orphans was also investigated in close relation to the welfare efforts of the elderly guardians. The investigations were made in respect of the contribution of the local resources towards the innovativeness of the elderly guardians. The adaptivity of the elderly and the versatility of the orphans were examined within the confines of the social and the economic capitals of the Hobodo ward. It is within the natural, social and economic capital dimensions of the Hobodo rural locality that the applicability of the sustainable livelihoods framework in explaining the dire social situation of the elderly and the orphans was brought under spotlight. The study was pursued through the qualitative research paradigm. This was done to capture the social perceptions, beliefs and the innovative capabilities of the elderly in their natural environment; and under the fieldwork setting. Several data collection techniques were employed to unveil the subject under study. These included interviews, questionnaires, participant observations, focus group discussions. Sampling was used to produce the research framework. Participants in the research were largely identified through random sampling. In special circumstances, purposive sampling was used. Tape recording and note taking were largely used to capture the responses of the research participants.
- Full Text:
- Authors: Marazi, Tafara
- Date: 2016
- Subjects: Rural elderly -- Zimbabwe , Elderly poor -- Zimbabwe , Ophans -- Services for -- Zimbabwe , AIDS (Disease) -- Zimbabwe , Child welfare -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3407 , http://hdl.handle.net/10962/d1020605
- Description: The thesis focuses on the survival mechanisms of the rural poor elderly in Zimbabwe. The situation of the rural elderly is looked at in the context of the ravaging HIV/AIDS pandemic. The focus is specifically directed on the increasing numbers of orphans who are generated following the rampant deaths of their parents (sexually active individuals). With Africa failing to effectively withstand the forcefulness of the pandemic, the community structures in Zimbabwe are being heavily shaken to the detriment of all social groups. It is within this continuum that the research is laid out to investigate the situation on the ground. In this case, a fieldwork exercise was carried out in the Hobodo ward of Mangwe district in Zimbabwe. An intensive and in-depth examination of the critical situation was pursued under the case study model. To make the study more focused, the elderly were placed under investigation with regards to their new role of providing familial care for the orphans. The manner in which they face such a towering task under strained resources and limited knowhow was explored. The well-being of the orphans was also investigated in close relation to the welfare efforts of the elderly guardians. The investigations were made in respect of the contribution of the local resources towards the innovativeness of the elderly guardians. The adaptivity of the elderly and the versatility of the orphans were examined within the confines of the social and the economic capitals of the Hobodo ward. It is within the natural, social and economic capital dimensions of the Hobodo rural locality that the applicability of the sustainable livelihoods framework in explaining the dire social situation of the elderly and the orphans was brought under spotlight. The study was pursued through the qualitative research paradigm. This was done to capture the social perceptions, beliefs and the innovative capabilities of the elderly in their natural environment; and under the fieldwork setting. Several data collection techniques were employed to unveil the subject under study. These included interviews, questionnaires, participant observations, focus group discussions. Sampling was used to produce the research framework. Participants in the research were largely identified through random sampling. In special circumstances, purposive sampling was used. Tape recording and note taking were largely used to capture the responses of the research participants.
- Full Text:
An investigation into the use of intuitive control interfaces and distributed processing for enhanced three dimensional sound localization
- Authors: Hedges, M L
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2992 , vital:20350
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimesional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. The successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
- Authors: Hedges, M L
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2992 , vital:20350
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimesional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. The successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
An investigation into the use of intuitive control interfaces and distributed processing for enhanced three dimensional sound localization
- Authors: Hedges, Mitchell Lawrence
- Date: 2016
- Subjects: Human-computer interaction , Acoustic localization , Sound -- Equipment and supplies , Acoustical engineering , Surround-sound systems , Wireless sensor nodes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4724 , http://hdl.handle.net/10962/d1020615
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
- Full Text:
- Authors: Hedges, Mitchell Lawrence
- Date: 2016
- Subjects: Human-computer interaction , Acoustic localization , Sound -- Equipment and supplies , Acoustical engineering , Surround-sound systems , Wireless sensor nodes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4724 , http://hdl.handle.net/10962/d1020615
- Description: This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.
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An investigation of absenteeism amongst blue-collar workers: a mixed methods approach
- Authors: Kroon, Kim
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:866 , http://hdl.handle.net/10962/d1021248
- Description: Absenteeism affects organisations in many different ways, therefore it is essential to investigate absenteeism with the aim of minimising absence levels. The focus of the research was to investigate absenteeism amongst blue-collar workers at a Global Logistics Supplier. The objectives of this research were to identify the main types of absenteeism, to compare the views of blue-collar workers and management on the causes attributed to absenteeism, to describe how absenteeism has been measured and managed, and to make recommendations to the company on ways to minimize absenteeism based on the findings. Quantitative data in the form of monthly absenteeism statistics relating to each leave type, was examined for trends relating to absenteeism levels amongst blue-collar workers at the company. Semi-structured interviews were then carried out with management and blue-collar workers to examine the causes of absenteeism and its management. The results showed that there was a discrepancy between the views of management and blue-collar workers at the company on the perceived causes of absenteeism. On the other hand, both management and the blue-collar workers identified Monday and Friday as the most prevalent days on which employees are absent from the workplace. This finding suggests that more research should be conducted on this trend in blue-collar workers. In exploring how absenteeism is dealt with, management within the company stated that discipline was the most effective way of keeping absenteeism levels low amongst employees. The limitations and delimitations of the research were recognised and further research ideas were given. It was also recommended that managers and supervisors address the workplace issues and identify when a worker’s performance and interpersonal relationships are strained in order to effectively minimise absenteeism. It is also recommended they implement a wellness programme.
- Full Text:
- Authors: Kroon, Kim
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:866 , http://hdl.handle.net/10962/d1021248
- Description: Absenteeism affects organisations in many different ways, therefore it is essential to investigate absenteeism with the aim of minimising absence levels. The focus of the research was to investigate absenteeism amongst blue-collar workers at a Global Logistics Supplier. The objectives of this research were to identify the main types of absenteeism, to compare the views of blue-collar workers and management on the causes attributed to absenteeism, to describe how absenteeism has been measured and managed, and to make recommendations to the company on ways to minimize absenteeism based on the findings. Quantitative data in the form of monthly absenteeism statistics relating to each leave type, was examined for trends relating to absenteeism levels amongst blue-collar workers at the company. Semi-structured interviews were then carried out with management and blue-collar workers to examine the causes of absenteeism and its management. The results showed that there was a discrepancy between the views of management and blue-collar workers at the company on the perceived causes of absenteeism. On the other hand, both management and the blue-collar workers identified Monday and Friday as the most prevalent days on which employees are absent from the workplace. This finding suggests that more research should be conducted on this trend in blue-collar workers. In exploring how absenteeism is dealt with, management within the company stated that discipline was the most effective way of keeping absenteeism levels low amongst employees. The limitations and delimitations of the research were recognised and further research ideas were given. It was also recommended that managers and supervisors address the workplace issues and identify when a worker’s performance and interpersonal relationships are strained in order to effectively minimise absenteeism. It is also recommended they implement a wellness programme.
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An investigation of green marketing opportunities at BOS Ice Tea
- Authors: Ciesielski, Adrian Adam
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:864 , http://hdl.handle.net/10962/d1021246
- Description: The research addresses the marketing activities of BOS Ice Tea, a South African company, and whether they are reflective and grounded within their marketing activities. By analysing public data and interviewing the founding partners, Richard Bowsher and Grant Rushmere, the findings where compared against the marketing paradigms of Ottoman (1999) and the green marketing practices of Gittell et al. (2012). It was determined that the company engages in green activities, but does not communicate them clearly. Further, where the company did promote organic rooibos and sustainability, their actions were not reflective of these behaviours from an academic point of view. Thus, there was the potential for green washing. The research concludes with suggestions for a 4P’s green marketing framework, and comments on areas that need clarity.
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- Authors: Ciesielski, Adrian Adam
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:864 , http://hdl.handle.net/10962/d1021246
- Description: The research addresses the marketing activities of BOS Ice Tea, a South African company, and whether they are reflective and grounded within their marketing activities. By analysing public data and interviewing the founding partners, Richard Bowsher and Grant Rushmere, the findings where compared against the marketing paradigms of Ottoman (1999) and the green marketing practices of Gittell et al. (2012). It was determined that the company engages in green activities, but does not communicate them clearly. Further, where the company did promote organic rooibos and sustainability, their actions were not reflective of these behaviours from an academic point of view. Thus, there was the potential for green washing. The research concludes with suggestions for a 4P’s green marketing framework, and comments on areas that need clarity.
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An investigation of participative management in a museum in the Eastern Cape, South Africa
- Authors: Madinda, Nozipho
- Date: 2016
- Subjects: Museums -- South Africa -- Eastern Cape -- Management , Management -- Employee participation , Albany Museum (Grahamstown, South Africa)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2068 , http://hdl.handle.net/10962/d1020847
- Description: The purpose of my research was to investigate participative management at the Albany Museum with a view to generating knowledge and insights that can be used to support senior management’s engagement with participative management at mid-management level. My interest was to investigate participative management with regards to five HODs of the Albany Museum with a view to generating knowledge and insights that can be used to support senior management’s engagement with participative management at mid-management level. The research was informed by the interpretive paradigm. The interpretive paradigm does not concern itself with the search for broadly applicable laws and rules but rather seeks to produce descriptive analyses that emphasise deep interpretation and understanding of social phenomena through the meaning that the people assign to them. This study is mostly descriptive and presents the reality of participants from their own experience. Semi-structured interviews and observation capture ‘insider’ knowledge that is part of an interpretive methodology. The study found that participative management was both understood and generally accepted as a good way to manage an organisation, and even members who were critical of it could see its benefits. However, the fractured and diversified structure of the organisation calls for a particularly skillful application of this management approach, one which would also demand leadership and a greater sense of working towards what are called collegial models of management. Whether this is in fact desirable for a museum is debatable.
- Full Text:
- Authors: Madinda, Nozipho
- Date: 2016
- Subjects: Museums -- South Africa -- Eastern Cape -- Management , Management -- Employee participation , Albany Museum (Grahamstown, South Africa)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2068 , http://hdl.handle.net/10962/d1020847
- Description: The purpose of my research was to investigate participative management at the Albany Museum with a view to generating knowledge and insights that can be used to support senior management’s engagement with participative management at mid-management level. My interest was to investigate participative management with regards to five HODs of the Albany Museum with a view to generating knowledge and insights that can be used to support senior management’s engagement with participative management at mid-management level. The research was informed by the interpretive paradigm. The interpretive paradigm does not concern itself with the search for broadly applicable laws and rules but rather seeks to produce descriptive analyses that emphasise deep interpretation and understanding of social phenomena through the meaning that the people assign to them. This study is mostly descriptive and presents the reality of participants from their own experience. Semi-structured interviews and observation capture ‘insider’ knowledge that is part of an interpretive methodology. The study found that participative management was both understood and generally accepted as a good way to manage an organisation, and even members who were critical of it could see its benefits. However, the fractured and diversified structure of the organisation calls for a particularly skillful application of this management approach, one which would also demand leadership and a greater sense of working towards what are called collegial models of management. Whether this is in fact desirable for a museum is debatable.
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An investigation of servant leadership within Rhodes University sports clubs
- Authors: Stiebel, Jessica Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:872 , http://hdl.handle.net/10962/d1021317
- Description: This research investigates the level of servant leadership within Rhodes University sport clubs. The goals of this research are to assess the perception the club members have of their chairperson and to key identify areas of development. The sport clubs at Rhodes University are partially run by chairpersons who are voted into the position by his or her peers of a sports club. The chairpersons work alongside Rhodes University employees who are a part of the Sports Administration team to oversee the running, scheduling and finances of the club. The sports clubs are representative of Rhodes University and it is the chairperson’s responsibility to ensure the club is lead and run effectively. Robert Greenleaf coined the term servant leader in the 1970s (Greenleaf, 1997). The servant leader is a leader who is driven by his or her followers, as leadership involves a leader serving his or her followers first and foremost (Greenleaf, 1977). The leader takes on a role that is supportive and contributes to their personal as well as their professional achievements (Smith, Montagno and Kuzmenko, 2004). A questionnaire consisting of 27 questions was drafted, of which were four demographic questions. A 5-point Likert Scale was used in order for the participants to respond to the questions. The questionnaire was drawn from a number of questionnaires available in literature on leadership and adapted to suit Rhodes University sports clubs. The questionnaire was distributed personally by the researcher, as well as through an online questionnaire. There were a total of 153 candidates who participated in the study. Descriptive statistics were used to analyse the data. The majority of the respondents had the perceptions that their chairperson displayed characteristics of a servant leader. Majority of the participants were in agreement of the questions asked in the questionnaire, which focused on many servant leadership qualities. The results will be handed over to the Head of Sports Administration in order for them to get an idea of their leaders’ characteristics and areas where they can improve upon.
- Full Text:
- Authors: Stiebel, Jessica Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:872 , http://hdl.handle.net/10962/d1021317
- Description: This research investigates the level of servant leadership within Rhodes University sport clubs. The goals of this research are to assess the perception the club members have of their chairperson and to key identify areas of development. The sport clubs at Rhodes University are partially run by chairpersons who are voted into the position by his or her peers of a sports club. The chairpersons work alongside Rhodes University employees who are a part of the Sports Administration team to oversee the running, scheduling and finances of the club. The sports clubs are representative of Rhodes University and it is the chairperson’s responsibility to ensure the club is lead and run effectively. Robert Greenleaf coined the term servant leader in the 1970s (Greenleaf, 1997). The servant leader is a leader who is driven by his or her followers, as leadership involves a leader serving his or her followers first and foremost (Greenleaf, 1977). The leader takes on a role that is supportive and contributes to their personal as well as their professional achievements (Smith, Montagno and Kuzmenko, 2004). A questionnaire consisting of 27 questions was drafted, of which were four demographic questions. A 5-point Likert Scale was used in order for the participants to respond to the questions. The questionnaire was drawn from a number of questionnaires available in literature on leadership and adapted to suit Rhodes University sports clubs. The questionnaire was distributed personally by the researcher, as well as through an online questionnaire. There were a total of 153 candidates who participated in the study. Descriptive statistics were used to analyse the data. The majority of the respondents had the perceptions that their chairperson displayed characteristics of a servant leader. Majority of the participants were in agreement of the questions asked in the questionnaire, which focused on many servant leadership qualities. The results will be handed over to the Head of Sports Administration in order for them to get an idea of their leaders’ characteristics and areas where they can improve upon.
- Full Text:
An investigation of the aquatic macroinvertebrate fauna of the southern Great Escarpment (South Africa): insights from ecological and genetic studies
- Authors: Taylor, Chantal Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4275 , http://hdl.handle.net/10962/d1020839
- Description: Biological diversity in freshwater biomes is vital to maintain healthy, functioning ecosystems with resilience to disturbance and the impacts of climate change. Freshwater ecosystems provide essential resources to life on Earth. However, as increasing pressure is being placed on the environment by human population growth, the quality of freshwater resources and the health of these ecosystems are at risk. Mountain streams provide an important source of water and are usually less affected by anthropogenic stressors, compared to lowland freshwaters. These montane streams are therefore of important conservation value and due to their untransformed nature serve as ideal ecosystems for biodiversity studies and as reference sites for studies on environmental change. This study explores aquatic macroinvertebrate biodiversity of the southern Great Escarpment in South Africa. Species assemblages and the environmental variables of each site were sampled from first order streams across five different mountain blocks along the Great Escarpment. Additionally, mitochondrial DNA of three mayfly species (Afroptilum sudafricanum, Demoreptus natalensis and Demoreptus capensis), commonly occurring in the study area, was analysed to compare the genetic diversity between habitat specialist and habitat generalist species. A total of 2 595 macroinvertebrate specimens from 47 families and 86 species were collected with several interesting and potentially new species being discovered. Partitioned diversity analyses indicate that macroinvertebrate diversity varies across mountain blocks. Multivariate analyses indicate that differences in assemblages could be attributed to differences in environmental variables between sites, particularly water velocity, total dissolved solids and salinity. As these environmental variables reflect of the topography of the sites, differences in species assemblages was attributed to difference in topography and therefore biotopes present. Habitat-restricted mayfly species (D. natalensis and D. capensis), occur in distinct populations confined to mountains blocks. Isolation-by-distance analyses further emphasis that these species are genetically restricted by their habitat preference for mountain streams. In contrast, A. sudafricanum, a habitat generalist, showed no indication of genetic structure due to location or distance. Possible cryptic taxa and new species were identified within A. sudafricanum and Dermoreptus respectively. This study provides an important contribution to the baseline data of freshwater macroinvertebrate diversity for the southern Great Escarpment region and provides insights into the considerable genetic diversity of selected aquatic taxa across this region.
- Full Text:
- Authors: Taylor, Chantal Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4275 , http://hdl.handle.net/10962/d1020839
- Description: Biological diversity in freshwater biomes is vital to maintain healthy, functioning ecosystems with resilience to disturbance and the impacts of climate change. Freshwater ecosystems provide essential resources to life on Earth. However, as increasing pressure is being placed on the environment by human population growth, the quality of freshwater resources and the health of these ecosystems are at risk. Mountain streams provide an important source of water and are usually less affected by anthropogenic stressors, compared to lowland freshwaters. These montane streams are therefore of important conservation value and due to their untransformed nature serve as ideal ecosystems for biodiversity studies and as reference sites for studies on environmental change. This study explores aquatic macroinvertebrate biodiversity of the southern Great Escarpment in South Africa. Species assemblages and the environmental variables of each site were sampled from first order streams across five different mountain blocks along the Great Escarpment. Additionally, mitochondrial DNA of three mayfly species (Afroptilum sudafricanum, Demoreptus natalensis and Demoreptus capensis), commonly occurring in the study area, was analysed to compare the genetic diversity between habitat specialist and habitat generalist species. A total of 2 595 macroinvertebrate specimens from 47 families and 86 species were collected with several interesting and potentially new species being discovered. Partitioned diversity analyses indicate that macroinvertebrate diversity varies across mountain blocks. Multivariate analyses indicate that differences in assemblages could be attributed to differences in environmental variables between sites, particularly water velocity, total dissolved solids and salinity. As these environmental variables reflect of the topography of the sites, differences in species assemblages was attributed to difference in topography and therefore biotopes present. Habitat-restricted mayfly species (D. natalensis and D. capensis), occur in distinct populations confined to mountains blocks. Isolation-by-distance analyses further emphasis that these species are genetically restricted by their habitat preference for mountain streams. In contrast, A. sudafricanum, a habitat generalist, showed no indication of genetic structure due to location or distance. Possible cryptic taxa and new species were identified within A. sudafricanum and Dermoreptus respectively. This study provides an important contribution to the baseline data of freshwater macroinvertebrate diversity for the southern Great Escarpment region and provides insights into the considerable genetic diversity of selected aquatic taxa across this region.
- Full Text:
An investigation of the barriers and drivers to CDM renewable energy investment at the Metro, Kouga and Jeffreys Bay windfarms
- Authors: Staples, Daryl Nolan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:871 , http://hdl.handle.net/10962/d1021316
- Description: This research is presented in three sections. Section 1 presents the research report in an academic journal article format. Section 2 provides a comprehensive literature review and Section 3 describes the research methodology and methods employed during the research. Climate change is the most urgent challenge facing planet earth today. The Intergovernmental Panel on Climate Change (IPCC) fifth assessment report (AR5) clearly states, “Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems” (IPCC, 2014:2). The Renewable Energy Policy Network for the 21st Century (REN21) published the 10th annual edition of the Renewables 2015 Global Status Report, which illustrates the importance of a zero emissions energy sector (REN21, 2015). Despite the world’s average annual 1,5% increase in energy consumption in recent years, and average 3% growth in Gross Domestic Product, carbon dioxide (CO2) emissions in 2014 were unchanged from 2013 levels (REN21, 2015). The report findings state, “For the first time in four decades, the world economy grew without a parallel rise in CO2 emissions” (REN21, 2015:17). Renewable energy and improved energy efficiency is key to limiting global warming and avoiding dangerous impacts from climate change (REN21, 2015). With a view to the successful outcome of the 21st Conference of the Parties (COP21) in December 2015, renewable energy could contribute significantly in mitigating climate change and supporting the Sustainable Development Goals (SDGs), specifically SDG 7, on Sustainable Energy for All (SAIREC, 2015). South Africa has been rated the 15th most attractive destination for investment in the renewable energy sector and could become a renewable energy leader in the African continent, according to the Renewable Energy Country Attractiveness Index of EY (Ernest and Young) (EY, 2015). And more...
- Full Text:
- Authors: Staples, Daryl Nolan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:871 , http://hdl.handle.net/10962/d1021316
- Description: This research is presented in three sections. Section 1 presents the research report in an academic journal article format. Section 2 provides a comprehensive literature review and Section 3 describes the research methodology and methods employed during the research. Climate change is the most urgent challenge facing planet earth today. The Intergovernmental Panel on Climate Change (IPCC) fifth assessment report (AR5) clearly states, “Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems” (IPCC, 2014:2). The Renewable Energy Policy Network for the 21st Century (REN21) published the 10th annual edition of the Renewables 2015 Global Status Report, which illustrates the importance of a zero emissions energy sector (REN21, 2015). Despite the world’s average annual 1,5% increase in energy consumption in recent years, and average 3% growth in Gross Domestic Product, carbon dioxide (CO2) emissions in 2014 were unchanged from 2013 levels (REN21, 2015). The report findings state, “For the first time in four decades, the world economy grew without a parallel rise in CO2 emissions” (REN21, 2015:17). Renewable energy and improved energy efficiency is key to limiting global warming and avoiding dangerous impacts from climate change (REN21, 2015). With a view to the successful outcome of the 21st Conference of the Parties (COP21) in December 2015, renewable energy could contribute significantly in mitigating climate change and supporting the Sustainable Development Goals (SDGs), specifically SDG 7, on Sustainable Energy for All (SAIREC, 2015). South Africa has been rated the 15th most attractive destination for investment in the renewable energy sector and could become a renewable energy leader in the African continent, according to the Renewable Energy Country Attractiveness Index of EY (Ernest and Young) (EY, 2015). And more...
- Full Text:
An investigation of the practices employed by an environmental community-based organization to successfully sustain its school based and community based projects (A case study)
- Authors: Hlophe, Nomalanga Nokuthula
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2073 , http://hdl.handle.net/10962/d1021252
- Description: Community-based organizations (CBOs) play a crucial role in sustainable development and hence it is important that they are promoted, guided and supported by state agencies and the private sector. The South African government encourages communities to establish co-operatives as a tool or strategy to address local social issues and risks and act accordingly. The purpose of this case study was to determine what aspects of the establishment and operation of a successful community-based environmental organization are producing sustained school and community projects. The study set out to investigate and audit the activities of a successful environmental CBO so as to determine how it has successfully sustained its school and community environmental projects. The reason for this investigation was to inform other CBOs and the state environmental agencies that support them on how to sustain their environmental activities in community and school contexts. The investigation was designed as an interpretive case study, which used document analysis, semi-structured interviews and observations to gather data. The gathered data was analyzed through inductive analysis to interpret and audit reported activities. Analytical memos were used to represent key themes in relation to the successful operations of the organization. Through auditing and reporting the activities in the analytical memos, analytical statements were developed. Those statements guided the discussion and informed the study‟s findings and recommendations. After investigating this CBO, it was concluded that, their success is a result of the establishment of a networking forum with different stakeholders and parties, community involvement in different projects, partnerships with local schools to develop and expand their curriculum practice, CBO networking locally and internationally and finally, their participation in annual and continuous environmental competitions/projects/programs. The insights gained and lessons learned will be used to advice and support community based co-operatives in environmental learning activities in school and community contexts as part of my ongoing work.
- Full Text:
- Authors: Hlophe, Nomalanga Nokuthula
- Date: 2016
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2073 , http://hdl.handle.net/10962/d1021252
- Description: Community-based organizations (CBOs) play a crucial role in sustainable development and hence it is important that they are promoted, guided and supported by state agencies and the private sector. The South African government encourages communities to establish co-operatives as a tool or strategy to address local social issues and risks and act accordingly. The purpose of this case study was to determine what aspects of the establishment and operation of a successful community-based environmental organization are producing sustained school and community projects. The study set out to investigate and audit the activities of a successful environmental CBO so as to determine how it has successfully sustained its school and community environmental projects. The reason for this investigation was to inform other CBOs and the state environmental agencies that support them on how to sustain their environmental activities in community and school contexts. The investigation was designed as an interpretive case study, which used document analysis, semi-structured interviews and observations to gather data. The gathered data was analyzed through inductive analysis to interpret and audit reported activities. Analytical memos were used to represent key themes in relation to the successful operations of the organization. Through auditing and reporting the activities in the analytical memos, analytical statements were developed. Those statements guided the discussion and informed the study‟s findings and recommendations. After investigating this CBO, it was concluded that, their success is a result of the establishment of a networking forum with different stakeholders and parties, community involvement in different projects, partnerships with local schools to develop and expand their curriculum practice, CBO networking locally and internationally and finally, their participation in annual and continuous environmental competitions/projects/programs. The insights gained and lessons learned will be used to advice and support community based co-operatives in environmental learning activities in school and community contexts as part of my ongoing work.
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An investigation on the effect of Russian wheat aphid (Diuraphis noxia Kurdjumov) population growth and feeding damage on selected barley (Hordeum vulgare L.) cultivars under ambient and elevated CO2
- Authors: Sacranie, Sattar Farouk
- Date: 2016
- Subjects: Russian wheat aphid -- Research -- South Africa Barley -- Disease and pest resistance -- South Africa Callose Aphids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50311 , vital:25975
- Description: The Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov) is a major pest of cultivated small grains. It is particularly devastating because of is high reproductive rate which results in the growth of large populations which become damaging to its host plants. Development of resistant barley (Hordeum vulgare L.) cultivars is complicated as resistance is polygenic. As a result, the industry remains at risk now that the RWA has spread throughout South Africa. It has, as recently as, 2013, been identified in the SW Cape, which was previously geographically isolated. This is South Africa‟s principle barley growing region. Now a potentially huge problem exists. Therefore, it is imperative that an alternative to pesticide use is found. Testing potential innate resistance in barley cultivars is thus, critical. In this thesis, I present data on four barely cultivars where I have examined their resistance/ lack of resistance to three known RWA biotypes, RWASA1, RWASA2 and RWASA3. The barley varieties used were two economically important South African malt barley cultivars (S5 and SSG 564) along with two potentially RWA resistant Afghan accessions (CIho 4125 and CIho 4159). The RWA biotype population growth rates on each of the plants were determined over a 14 day period. The aim was to establish baseline data of the effects of RWA population growth on the host plants under ambient CO2 (380 – 400 ppm) conditions. The extent of RWA feeding damage was investigated at the cell level by examining saliva deposition and cell disruption using Transmission Electron Microscopy; at the tissue/vascular level using fluorescence microscopy, to determine the extent of callose formation; at a whole leaf level by recording percent chlorosis and leaf roll; and finally, at a whole plant level by measuring biomass loss.The experiments were repeated under elevated CO2 (450 ppm) to model any changes in RWA/plant interaction with respect to future climate change. The effects of an elevated CO2 environment and RWA feeding on host plant foliar N and C:N ratio were compared to ambient CO2 conditions, to provide a clearer picture of the potential nutrient drain that a feeding RWA colony exacts on its host. Of the varieties tested, the CIho accessions performed better than the two SA barley cultivars as the CIho accessions appeared to express a mild antibiosis resistance response as RWA populations, particularly those of RWASA1, were smaller than those observed on either S5 or SSG 564. In addition, less damage was evident in the two CIho accessions due to RWA feeding. II RWASA2 was the most virulent of the three RWA biotypes tested, followed by RWASA3 while RWASA1 was the least virulent. Under elevated CO2 conditions, RWA feeding damage was exacerbated but the trend of biotype virulence remained the same. Higher aphid population sizes were recorded under elevated CO2, meant that even the more resistant CIho accessions were overcome by the increased demand made by the larger aphid colonies on the host plants. The % foliar N data showed that under elevated CO2 aphid-free control plants had increased N levels in their leaves. Increased “food” supply (as shown by the increased N levels) therefore allowed significantly larger aphid populations to develop on the plants exposed to elevated CO2, due to improved nutrient status of the phloem sap taken up by RWA. The knock-on effect of a higher aphid population was increased cell disruption as a result of extensive probing, extensive formations of wound callose, with the result that phloem damage impeded nutrient flow through the vascular tissues which contributed to chlorosis and (eventually plant) death. The major conclusion from this study is that even a mild CO2 elevation resulted in an increase aphid population which may pose a severe and very real threat to a barley crop. Therefore, without effort to identify and deploy resistant barley cultivars, it could well be possible that future barley cultivation in South Africa may no longer be viable.
- Full Text:
- Authors: Sacranie, Sattar Farouk
- Date: 2016
- Subjects: Russian wheat aphid -- Research -- South Africa Barley -- Disease and pest resistance -- South Africa Callose Aphids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50311 , vital:25975
- Description: The Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov) is a major pest of cultivated small grains. It is particularly devastating because of is high reproductive rate which results in the growth of large populations which become damaging to its host plants. Development of resistant barley (Hordeum vulgare L.) cultivars is complicated as resistance is polygenic. As a result, the industry remains at risk now that the RWA has spread throughout South Africa. It has, as recently as, 2013, been identified in the SW Cape, which was previously geographically isolated. This is South Africa‟s principle barley growing region. Now a potentially huge problem exists. Therefore, it is imperative that an alternative to pesticide use is found. Testing potential innate resistance in barley cultivars is thus, critical. In this thesis, I present data on four barely cultivars where I have examined their resistance/ lack of resistance to three known RWA biotypes, RWASA1, RWASA2 and RWASA3. The barley varieties used were two economically important South African malt barley cultivars (S5 and SSG 564) along with two potentially RWA resistant Afghan accessions (CIho 4125 and CIho 4159). The RWA biotype population growth rates on each of the plants were determined over a 14 day period. The aim was to establish baseline data of the effects of RWA population growth on the host plants under ambient CO2 (380 – 400 ppm) conditions. The extent of RWA feeding damage was investigated at the cell level by examining saliva deposition and cell disruption using Transmission Electron Microscopy; at the tissue/vascular level using fluorescence microscopy, to determine the extent of callose formation; at a whole leaf level by recording percent chlorosis and leaf roll; and finally, at a whole plant level by measuring biomass loss.The experiments were repeated under elevated CO2 (450 ppm) to model any changes in RWA/plant interaction with respect to future climate change. The effects of an elevated CO2 environment and RWA feeding on host plant foliar N and C:N ratio were compared to ambient CO2 conditions, to provide a clearer picture of the potential nutrient drain that a feeding RWA colony exacts on its host. Of the varieties tested, the CIho accessions performed better than the two SA barley cultivars as the CIho accessions appeared to express a mild antibiosis resistance response as RWA populations, particularly those of RWASA1, were smaller than those observed on either S5 or SSG 564. In addition, less damage was evident in the two CIho accessions due to RWA feeding. II RWASA2 was the most virulent of the three RWA biotypes tested, followed by RWASA3 while RWASA1 was the least virulent. Under elevated CO2 conditions, RWA feeding damage was exacerbated but the trend of biotype virulence remained the same. Higher aphid population sizes were recorded under elevated CO2, meant that even the more resistant CIho accessions were overcome by the increased demand made by the larger aphid colonies on the host plants. The % foliar N data showed that under elevated CO2 aphid-free control plants had increased N levels in their leaves. Increased “food” supply (as shown by the increased N levels) therefore allowed significantly larger aphid populations to develop on the plants exposed to elevated CO2, due to improved nutrient status of the phloem sap taken up by RWA. The knock-on effect of a higher aphid population was increased cell disruption as a result of extensive probing, extensive formations of wound callose, with the result that phloem damage impeded nutrient flow through the vascular tissues which contributed to chlorosis and (eventually plant) death. The major conclusion from this study is that even a mild CO2 elevation resulted in an increase aphid population which may pose a severe and very real threat to a barley crop. Therefore, without effort to identify and deploy resistant barley cultivars, it could well be possible that future barley cultivation in South Africa may no longer be viable.
- Full Text:
An overview of language policy implementation in the City of Tswane Metropolitan Municipality with a focus on translation as an activity of language policy implementation
- Seshoka, Keaobaka Omphile Precious
- Authors: Seshoka, Keaobaka Omphile Precious
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/932 , vital:20004
- Description: The South African Municipality Systems Act (2000) states that language should not act as a barrier of access for citizens with no or limited proficiency in English to municipal services, or in ensuring the right of citizens to participate in, and contribute to the social, cultural, intellectual, economic and political life of South African society. In that regard, it recommends that South African municipalities develop a culture of public participation by providing services in a language preferred and used by citizens within their municipality through translation, amongst other things. This study examines how the translation services, as articulated in the language policy and plan of the City of Tshwane Metropolitan Municipality, is used as a language implementation strategy and in facilitating public participation. It further assesses the quality of the translated information accessed by the different residents of the City of Tshwane Metropolitan Municipality against theories of translation appraisal. The main focus area of this research is on extent of the use of translation as an activity of corpus planning, to facilitate language policy implementation in the City of Tshwane Municipality to enable better public participation. It is hoped that the study will be able to give policy makers and those tasked with implementation, especially at government municipalities‘ strategies to assess and determine the state of translation services to improve functionality, quality and the extent to which translation activities contribute to corpus planning.
- Full Text:
- Authors: Seshoka, Keaobaka Omphile Precious
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/932 , vital:20004
- Description: The South African Municipality Systems Act (2000) states that language should not act as a barrier of access for citizens with no or limited proficiency in English to municipal services, or in ensuring the right of citizens to participate in, and contribute to the social, cultural, intellectual, economic and political life of South African society. In that regard, it recommends that South African municipalities develop a culture of public participation by providing services in a language preferred and used by citizens within their municipality through translation, amongst other things. This study examines how the translation services, as articulated in the language policy and plan of the City of Tshwane Metropolitan Municipality, is used as a language implementation strategy and in facilitating public participation. It further assesses the quality of the translated information accessed by the different residents of the City of Tshwane Metropolitan Municipality against theories of translation appraisal. The main focus area of this research is on extent of the use of translation as an activity of corpus planning, to facilitate language policy implementation in the City of Tshwane Municipality to enable better public participation. It is hoped that the study will be able to give policy makers and those tasked with implementation, especially at government municipalities‘ strategies to assess and determine the state of translation services to improve functionality, quality and the extent to which translation activities contribute to corpus planning.
- Full Text:
Aquatic–terrestrial trophic linkages via riverine invertebrates in a South African catchment
- Authors: Moyo, Sydney
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54427 , vital:26564
- Description: Rivers play a vital role in human livelihoods and are likely to undergo substantial alteration due to climate and land use changes from an increasing human population. Mitigating the pressures facing rivers in the world requires scientists and environmental managers to understand the ecological mechanisms, and ultimately the strength, of connections between ecosystems. This understanding of connections between adjacent habitats will enable environmental managers to predict the consequences of perturbing these linkages in the future. In this thesis, aquatic-terrestrial linkages in rivers were investigated using ecologically meaningful variables including abundances, biomasses, stable isotopes and fatty acids. This study is part of a larger project entitled “Connectivity through allochthony: reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa”, in which a team of researchers assessed a variety of pathways connecting riverine and estuarine systems to land within a catchment in the Eastern Cape, South Africa. I conceptualised the flow of energy within a temperate southern hemisphere river (the Kowie River) within theoretical models of energy flow such as the River Continuum Concept (RCC; presents lotic systems as being longitudinally linked with food webs in shaded headwaters being principally driven by allochthonous energy, with the addition of autochthonous food as a minor carbon source in the lower reaches) and the Riverine Productivity Model (RPM; proposes consumers derive most of their energy from local production of phytoplankton, benthic algae and aquatic plants, as well as directly from riparian zones via terrestrial leaf litter). Using the RCC as a starting point, I collected macroinvertebrates (September 2012 to May 2013) along a longitudinal gradient and grouped them into functional feeding groups (FFGs). The results revealed that gatherers and filterers dominated in the Kowie River, and together represented 50 – 83% of the invertebrate assemblages. There was a general paucity of shredders (relative abundance was ≤ 10% across all sites and seasons). The changes in relative abundances of different FFGs did not follow predictions of the RCC along the longitudinal gradient, as there were no correlations of community structure with some physical attributes (stream width, canopy cover, distance of river) that changed along the river continuum. However, FFG abundances were related to water velocity, total dissolved solids and canopy cover. Broadly, the Kowie River data showed that changes in relative abundances of FFGs along the river continuum could not be explained by changes in physical attributes alone, and may be highly influenced by the availability of food and the chemistry of the stream. Analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes was used to estimate the contributions of algal and land-based production to consumers over space (six sites) and time (November 2012 to September 2013). Carbon contributions determined by the use of mixing models (Stable Isotope Analysis in R) revealed that consumers in the headwater assimilated mainly terrestrially-derived organic matter, with consumers in the middle and lower reaches assimilating autochthonous basal resources (macrophytes and algae). The findings from this river supported aspects of the RCC (at the headwaters; terrestrial organic matter made up 41% of consumer diets), but overall the data supported the predictions of the RPM (local production made the highest contributions of 50 – 86% to all FFGs across all seasons). The carbon isotopes of consumers and their food sources changed substantially every season, indicating that samples of food sources and consumers should be analysed many times throughout the year to capture that variability and to ensure that ephemeral components of the food web are not missed. To validate the findings from the isotope data, fatty acids were used as complementary tracers to determine the contributions of algal versus terrestrial organic matter to the consumers. Fatty acid tracers for terrestrial (Ʃω3/Ʃω6; 18:2ω6; 18:3ω3) vs aquatic (Ʃω3/Ʃω6; 20:5ω3) sources corroborated the findings from the isotope data set, as the mean ratio of Ʃω3/Ʃω6 in consumers was less than one at the headwaters (indicating allochthony), while middle and lower reaches were associated with Ʃω3/Ʃω6 > 1 (indicating autochthony). In addition to the tracer and FFG analyses for examining trophic connections between land and river, the bidirectional exchange of organisms between the riparian zone and the river was assessed using floating pyramidal traps (to measure emergence) and pan traps (for infalling invertebrates) placed at different sites in the river and the biomass in each trap was determined. The exchanges were variable over space and time, with emergence peaking in summer (169 to 1402 mg m-2 day-1) and declining in winter (3 to 28 mg m-2 day-1). Similarly, infalling invertebrates increased in summer (413 to 679 mg m-2 day-1) and declined in winter (11 to 220 mg m-2 day-1). Biomass measurements are indications of quantity that ignore nutritional quality, so I determined the bidirectional flow of invertebrates using absolute concentrations of physiologically important biochemical compounds (essential and polyunsaturated fatty acids). The fluxes of emergent and infalling arthropods peaked in summer (emergence = 0.3 to 18 mg m-2 day-1 and terrestrial infall = 0.3 to 3 mg m-2 day-1) and declined in winter (emergence = 0.01 to 0.51 mg m-2 day-1 and terrestrial infall = 0.01 to 0.03 mg m-2 day-1). However, during some seasons, no significant differences in polyunsaturated fatty acid flux in either direction were observed; this finding indicated the balance of reciprocal subsidisation via reciprocal flows of animals. Factors such as air temperature and algal productivity affected the reciprocal flows between adjacent habitats, with algal productivity being positively related to emergence while air temperature was positively correlated to infalling terrestrial invertebrates. This research enhances the growing body of literature on the function of riverine systems and offers some invaluable information on the flow of energy and the role played by invertebrates in translocating nutrients from terrestrial systems to aquatic systems and vice versa. This study unifies the concepts of the RCC and RPM and shows that these concepts are not limited only to large rivers, but are applicable to small southern temperate rivers too. However, some tenets of the theoretical models were challenged. For example, it challenges the proposition by the RCC that the fine particulate organic matter leaked from upstream breakdown of coarse particulate organic matter is predominantly allochthonous. Additionally, this study showed that in the headwaters, the RPM underestimated the role of autochthony. Overall, the results showed that the Kowie River and its riparian area are intrinsically connected. Once we understand the mechanisms controlling connections and subsidies across ecotones, we can then start to predict the consequences of disruptions to these connections by climate change and/or land use changes. To make predictions about future perturbations to rivers and riparian zones, studies like this, which considers the form and magnitude of subsidies, are needed to provide baseline information. Algal resources (e.g. epiphyton), macrophytes, riparian plants, terrestrial organisms and aquatic organisms all contributed to aquatic and terrestrial linkages in the Kowie River; therefore, it is important to conserve the different components of these ecosystems.
- Full Text:
- Authors: Moyo, Sydney
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54427 , vital:26564
- Description: Rivers play a vital role in human livelihoods and are likely to undergo substantial alteration due to climate and land use changes from an increasing human population. Mitigating the pressures facing rivers in the world requires scientists and environmental managers to understand the ecological mechanisms, and ultimately the strength, of connections between ecosystems. This understanding of connections between adjacent habitats will enable environmental managers to predict the consequences of perturbing these linkages in the future. In this thesis, aquatic-terrestrial linkages in rivers were investigated using ecologically meaningful variables including abundances, biomasses, stable isotopes and fatty acids. This study is part of a larger project entitled “Connectivity through allochthony: reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa”, in which a team of researchers assessed a variety of pathways connecting riverine and estuarine systems to land within a catchment in the Eastern Cape, South Africa. I conceptualised the flow of energy within a temperate southern hemisphere river (the Kowie River) within theoretical models of energy flow such as the River Continuum Concept (RCC; presents lotic systems as being longitudinally linked with food webs in shaded headwaters being principally driven by allochthonous energy, with the addition of autochthonous food as a minor carbon source in the lower reaches) and the Riverine Productivity Model (RPM; proposes consumers derive most of their energy from local production of phytoplankton, benthic algae and aquatic plants, as well as directly from riparian zones via terrestrial leaf litter). Using the RCC as a starting point, I collected macroinvertebrates (September 2012 to May 2013) along a longitudinal gradient and grouped them into functional feeding groups (FFGs). The results revealed that gatherers and filterers dominated in the Kowie River, and together represented 50 – 83% of the invertebrate assemblages. There was a general paucity of shredders (relative abundance was ≤ 10% across all sites and seasons). The changes in relative abundances of different FFGs did not follow predictions of the RCC along the longitudinal gradient, as there were no correlations of community structure with some physical attributes (stream width, canopy cover, distance of river) that changed along the river continuum. However, FFG abundances were related to water velocity, total dissolved solids and canopy cover. Broadly, the Kowie River data showed that changes in relative abundances of FFGs along the river continuum could not be explained by changes in physical attributes alone, and may be highly influenced by the availability of food and the chemistry of the stream. Analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes was used to estimate the contributions of algal and land-based production to consumers over space (six sites) and time (November 2012 to September 2013). Carbon contributions determined by the use of mixing models (Stable Isotope Analysis in R) revealed that consumers in the headwater assimilated mainly terrestrially-derived organic matter, with consumers in the middle and lower reaches assimilating autochthonous basal resources (macrophytes and algae). The findings from this river supported aspects of the RCC (at the headwaters; terrestrial organic matter made up 41% of consumer diets), but overall the data supported the predictions of the RPM (local production made the highest contributions of 50 – 86% to all FFGs across all seasons). The carbon isotopes of consumers and their food sources changed substantially every season, indicating that samples of food sources and consumers should be analysed many times throughout the year to capture that variability and to ensure that ephemeral components of the food web are not missed. To validate the findings from the isotope data, fatty acids were used as complementary tracers to determine the contributions of algal versus terrestrial organic matter to the consumers. Fatty acid tracers for terrestrial (Ʃω3/Ʃω6; 18:2ω6; 18:3ω3) vs aquatic (Ʃω3/Ʃω6; 20:5ω3) sources corroborated the findings from the isotope data set, as the mean ratio of Ʃω3/Ʃω6 in consumers was less than one at the headwaters (indicating allochthony), while middle and lower reaches were associated with Ʃω3/Ʃω6 > 1 (indicating autochthony). In addition to the tracer and FFG analyses for examining trophic connections between land and river, the bidirectional exchange of organisms between the riparian zone and the river was assessed using floating pyramidal traps (to measure emergence) and pan traps (for infalling invertebrates) placed at different sites in the river and the biomass in each trap was determined. The exchanges were variable over space and time, with emergence peaking in summer (169 to 1402 mg m-2 day-1) and declining in winter (3 to 28 mg m-2 day-1). Similarly, infalling invertebrates increased in summer (413 to 679 mg m-2 day-1) and declined in winter (11 to 220 mg m-2 day-1). Biomass measurements are indications of quantity that ignore nutritional quality, so I determined the bidirectional flow of invertebrates using absolute concentrations of physiologically important biochemical compounds (essential and polyunsaturated fatty acids). The fluxes of emergent and infalling arthropods peaked in summer (emergence = 0.3 to 18 mg m-2 day-1 and terrestrial infall = 0.3 to 3 mg m-2 day-1) and declined in winter (emergence = 0.01 to 0.51 mg m-2 day-1 and terrestrial infall = 0.01 to 0.03 mg m-2 day-1). However, during some seasons, no significant differences in polyunsaturated fatty acid flux in either direction were observed; this finding indicated the balance of reciprocal subsidisation via reciprocal flows of animals. Factors such as air temperature and algal productivity affected the reciprocal flows between adjacent habitats, with algal productivity being positively related to emergence while air temperature was positively correlated to infalling terrestrial invertebrates. This research enhances the growing body of literature on the function of riverine systems and offers some invaluable information on the flow of energy and the role played by invertebrates in translocating nutrients from terrestrial systems to aquatic systems and vice versa. This study unifies the concepts of the RCC and RPM and shows that these concepts are not limited only to large rivers, but are applicable to small southern temperate rivers too. However, some tenets of the theoretical models were challenged. For example, it challenges the proposition by the RCC that the fine particulate organic matter leaked from upstream breakdown of coarse particulate organic matter is predominantly allochthonous. Additionally, this study showed that in the headwaters, the RPM underestimated the role of autochthony. Overall, the results showed that the Kowie River and its riparian area are intrinsically connected. Once we understand the mechanisms controlling connections and subsidies across ecotones, we can then start to predict the consequences of disruptions to these connections by climate change and/or land use changes. To make predictions about future perturbations to rivers and riparian zones, studies like this, which considers the form and magnitude of subsidies, are needed to provide baseline information. Algal resources (e.g. epiphyton), macrophytes, riparian plants, terrestrial organisms and aquatic organisms all contributed to aquatic and terrestrial linkages in the Kowie River; therefore, it is important to conserve the different components of these ecosystems.
- Full Text: