An exploration of knowledge sharing as a means of improving municipal governance in selected Limpopo municipalities
- Dikotla, Maoka Andries https://orcid.org/0000-0002-6699-6782
- Authors: Dikotla, Maoka Andries https://orcid.org/0000-0002-6699-6782
- Date: 2016-08
- Subjects: Knowledge management , Information services , Organizational learning
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24750 , vital:63548
- Description: The aim of this study was to underscore the role of knowledge sharing in improving the municipal governance in the local government sector of South Africa. The objectives of the study were to find out the kind of knowledge management programmes which are in place in the municipalities of Limpopo Province; establish the extent to which municipalities in Limpopo encourage knowledge sharing for improvement of municipal governance; determine factors which affect knowledge sharing among employees of municipalities of Limpopo Province, and propose recommendations and strategies on how to optimally share knowledge in Limpopo municipalities. The nature of this study warranted the use of two research paradigms, namely positivist and interpretivist approaches. The study employed an integrated research method which covered both the qualitative and quantitative approach. In collecting data, data instruments were triangulated. In this regard, the researcher mostly used a questionnaire with little employment of interviews and observation. The researcher sampled 438 employees and 21 managers from the selected municipalities. Quantitative data was analysed using IBM Statistical Package for Social Science (SPSS) version 23. Qualitative data was analysed using thematic analysis. The major findings of the study are the following: poor knowledge management programmes in Limpopo municipalities, knowledge sharing among the employees and across the municipalities is not encouraged, knowledge sharing in Limpopo municipalities is affected by both individual and organisational barriers and under-utilisation of information communication technology tools to support knowledge management programmes and practices. Comparatively, the findings of this study to a large extent support what has been recorded in literature. However, the study contradicts a typical mind set of many people that “knowledge is power” and cannot be shared freely. The study recommended to Limpopo municipalities to develop Knowledge sharing strategies that need to be linked to municipal strategic plans; involvement of top management in knowledge management activities; development of knowledge-friendly culture and utilisation of information communication technology tools in support of knowledge sharing. Some recommendations for further study were also provided. Among others, the study recommended that a study on the use of incentive systems as a means of encouraging knowledge sharing be conducted in selected municipalities. This was because studies on the use of incentive systems for motivating knowledge sharing yielded contradictory findings in many organisations. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2016
- Full Text:
- Date Issued: 2016-08
- Authors: Dikotla, Maoka Andries https://orcid.org/0000-0002-6699-6782
- Date: 2016-08
- Subjects: Knowledge management , Information services , Organizational learning
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24750 , vital:63548
- Description: The aim of this study was to underscore the role of knowledge sharing in improving the municipal governance in the local government sector of South Africa. The objectives of the study were to find out the kind of knowledge management programmes which are in place in the municipalities of Limpopo Province; establish the extent to which municipalities in Limpopo encourage knowledge sharing for improvement of municipal governance; determine factors which affect knowledge sharing among employees of municipalities of Limpopo Province, and propose recommendations and strategies on how to optimally share knowledge in Limpopo municipalities. The nature of this study warranted the use of two research paradigms, namely positivist and interpretivist approaches. The study employed an integrated research method which covered both the qualitative and quantitative approach. In collecting data, data instruments were triangulated. In this regard, the researcher mostly used a questionnaire with little employment of interviews and observation. The researcher sampled 438 employees and 21 managers from the selected municipalities. Quantitative data was analysed using IBM Statistical Package for Social Science (SPSS) version 23. Qualitative data was analysed using thematic analysis. The major findings of the study are the following: poor knowledge management programmes in Limpopo municipalities, knowledge sharing among the employees and across the municipalities is not encouraged, knowledge sharing in Limpopo municipalities is affected by both individual and organisational barriers and under-utilisation of information communication technology tools to support knowledge management programmes and practices. Comparatively, the findings of this study to a large extent support what has been recorded in literature. However, the study contradicts a typical mind set of many people that “knowledge is power” and cannot be shared freely. The study recommended to Limpopo municipalities to develop Knowledge sharing strategies that need to be linked to municipal strategic plans; involvement of top management in knowledge management activities; development of knowledge-friendly culture and utilisation of information communication technology tools in support of knowledge sharing. Some recommendations for further study were also provided. Among others, the study recommended that a study on the use of incentive systems as a means of encouraging knowledge sharing be conducted in selected municipalities. This was because studies on the use of incentive systems for motivating knowledge sharing yielded contradictory findings in many organisations. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2016
- Full Text:
- Date Issued: 2016-08
Entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape province, South Africa
- Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Authors: Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Date: 2016-07
- Subjects: Farms, Small , Irrigation farming -- Economic aspects
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24906 , vital:63670
- Description: South Africa has implemented several successful rural poverty relief initiatives; however, poverty continues to strain rural development efforts. The aim of the study was to analyse the entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape Province of South Africa. The study has outlined five hypothesizes for the basis of concrete scientific research. Initially the study hypothesizes that a smallholder’s socio-cultural contexts such as village level institutions especially village governance as well as household circumstances including age, education and gender compositions of the household membership as well as household income can determine a smallholder’s transformation ability. The second hypothesis was that alternative economic activities especially farming activities such as livestock and crop production as well as off-farm economic opportunities which were open to a household could influence a smallholder’s willingness to change from homestead gardening to food crop production under government irrigation programme. The third hypothesis was on the smallholder’s assessment of available market for the products of his or her food crop irrigation farming which could be an important consideration in his or her willingness to change. The fourth assumption was that entrepreneurial skills are lacking, in particular the ability to search for opportunities and willingness to do something different than the masses and take risks in that process. Finally, the study hypothesized that the government irrigation scheme governance could determine the attractiveness of the scheme and thereby influencing the willingness of a smallholder to participate. Specifically, the legal and regulatory environments are very restrictive and they are not conducive to effective value and job creation in the villages and for the principal crop and livestock enterprises. The study used cross-sectional data collected from both scheme farmers and non-scheme farmers. There were 107 smallholder farmers administered. Cobb-Douglass production and Multiple Regression Models were used. The results indicated 62 percent were male household head and 38 percent were female household head. The majority of the farmers were above middle age for both men and women households head. Specifically, about 80percent were above 51 years of age. Wage employment on the other hand contributed 8percent for both scheme and non-scheme farmers. The majority of the family members were dominated by students and pensioners indicating 27percent of the respondents who were unemployed, among them students were included and pensioners were indicated by 9percent. The overall findings were that there are important differences in behavior regarding the transition from homestead gardening to irrigation farming. Smallholder farmers of Mnquma and Mbhashe municipalities have a great potential in maize, beans, potatoes, pumpkin, butternut production, as well as cattle, sheep, goats, pigs and poultry production. Lastly, the study has highlighted various factors affecting livelihoods sources. Therefore, there is a need for these smallholder farmers to engage consistently with the market to enhance information flow. Extension officers must play a role using the recent extension approach of participatory rural appraisal through discussions with farmers and empower them for marketing problems and solutions. Smallholder farmers must ensure frequent consultation with extension or agricultural advisors for financial and production input support. Government need to strengthen agricultural activities in the rural areas in order to sustain rural livelihoods for rural dwellers. Once the rural economy becomes transformed through agricultural activities then rural dwellers can achieve good standard of living in line with a key macroeconomic objective the South African government. , Thesis (PhD) -- Faculty of Science and Agriculture, 2016
- Full Text:
- Date Issued: 2016-07
- Authors: Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Date: 2016-07
- Subjects: Farms, Small , Irrigation farming -- Economic aspects
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24906 , vital:63670
- Description: South Africa has implemented several successful rural poverty relief initiatives; however, poverty continues to strain rural development efforts. The aim of the study was to analyse the entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape Province of South Africa. The study has outlined five hypothesizes for the basis of concrete scientific research. Initially the study hypothesizes that a smallholder’s socio-cultural contexts such as village level institutions especially village governance as well as household circumstances including age, education and gender compositions of the household membership as well as household income can determine a smallholder’s transformation ability. The second hypothesis was that alternative economic activities especially farming activities such as livestock and crop production as well as off-farm economic opportunities which were open to a household could influence a smallholder’s willingness to change from homestead gardening to food crop production under government irrigation programme. The third hypothesis was on the smallholder’s assessment of available market for the products of his or her food crop irrigation farming which could be an important consideration in his or her willingness to change. The fourth assumption was that entrepreneurial skills are lacking, in particular the ability to search for opportunities and willingness to do something different than the masses and take risks in that process. Finally, the study hypothesized that the government irrigation scheme governance could determine the attractiveness of the scheme and thereby influencing the willingness of a smallholder to participate. Specifically, the legal and regulatory environments are very restrictive and they are not conducive to effective value and job creation in the villages and for the principal crop and livestock enterprises. The study used cross-sectional data collected from both scheme farmers and non-scheme farmers. There were 107 smallholder farmers administered. Cobb-Douglass production and Multiple Regression Models were used. The results indicated 62 percent were male household head and 38 percent were female household head. The majority of the farmers were above middle age for both men and women households head. Specifically, about 80percent were above 51 years of age. Wage employment on the other hand contributed 8percent for both scheme and non-scheme farmers. The majority of the family members were dominated by students and pensioners indicating 27percent of the respondents who were unemployed, among them students were included and pensioners were indicated by 9percent. The overall findings were that there are important differences in behavior regarding the transition from homestead gardening to irrigation farming. Smallholder farmers of Mnquma and Mbhashe municipalities have a great potential in maize, beans, potatoes, pumpkin, butternut production, as well as cattle, sheep, goats, pigs and poultry production. Lastly, the study has highlighted various factors affecting livelihoods sources. Therefore, there is a need for these smallholder farmers to engage consistently with the market to enhance information flow. Extension officers must play a role using the recent extension approach of participatory rural appraisal through discussions with farmers and empower them for marketing problems and solutions. Smallholder farmers must ensure frequent consultation with extension or agricultural advisors for financial and production input support. Government need to strengthen agricultural activities in the rural areas in order to sustain rural livelihoods for rural dwellers. Once the rural economy becomes transformed through agricultural activities then rural dwellers can achieve good standard of living in line with a key macroeconomic objective the South African government. , Thesis (PhD) -- Faculty of Science and Agriculture, 2016
- Full Text:
- Date Issued: 2016-07
Cultural and social factors affecting crop production at Gqumahashe and Melani, Alice District
- Komanisi, Mzwandile Paul 0000-0003-0866-666X
- Authors: Komanisi, Mzwandile Paul 0000-0003-0866-666X
- Date: 2016-06
- Subjects: Sharecropping , Food crops
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23023 , vital:55001
- Description: Over the years, sharecropping and work-parties have been seen as variables that maintain social cohesion among people and maximize agricultural production. This study seeks to validate the authenticity of this assertion in the context of two neighbouring villages. Although there are other variables that affect crop production in the study areas, Lower Gqumahashe and Melani, in the light of time constraints and the insignificant impact of these variables, the study focused only on sharecropping and work-parties. The study adopted empirical research design. The researcher realised that empirical research design would offer him an opportunity for intense or prolonged contact with informants in order to have a holistic picture of their behaviour. The researcher did not choose theoretical research design because it would not allow him to have an extensive interaction with informants since it relies on secondary data. The findings of the study suggest that sharecropping and work parties are the main variables that hinder the rate of crop production in the study areas. However, there are other secondary variables hindering crop production but they have insignificant impact. These are clan and kinship relations, political structure, religion and social identity. This study concludes that although local informants were in favour of sharecropping and work-parties in the past, they have discontinued them due to exploitation and hoodwinking. , Thesis (PhD) -- Faculty of Social Science and Humanities, 2016
- Full Text:
- Date Issued: 2016-06
- Authors: Komanisi, Mzwandile Paul 0000-0003-0866-666X
- Date: 2016-06
- Subjects: Sharecropping , Food crops
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23023 , vital:55001
- Description: Over the years, sharecropping and work-parties have been seen as variables that maintain social cohesion among people and maximize agricultural production. This study seeks to validate the authenticity of this assertion in the context of two neighbouring villages. Although there are other variables that affect crop production in the study areas, Lower Gqumahashe and Melani, in the light of time constraints and the insignificant impact of these variables, the study focused only on sharecropping and work-parties. The study adopted empirical research design. The researcher realised that empirical research design would offer him an opportunity for intense or prolonged contact with informants in order to have a holistic picture of their behaviour. The researcher did not choose theoretical research design because it would not allow him to have an extensive interaction with informants since it relies on secondary data. The findings of the study suggest that sharecropping and work parties are the main variables that hinder the rate of crop production in the study areas. However, there are other secondary variables hindering crop production but they have insignificant impact. These are clan and kinship relations, political structure, religion and social identity. This study concludes that although local informants were in favour of sharecropping and work-parties in the past, they have discontinued them due to exploitation and hoodwinking. , Thesis (PhD) -- Faculty of Social Science and Humanities, 2016
- Full Text:
- Date Issued: 2016-06
The implementation of foundational provision programmes in a rural based University in South Africa: implications for student academic development practices
- Authors: Marhaya, Luyanda
- Date: 2016-05
- Subjects: Education, Higher -- South Africa , College student development programs
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24706 , vital:63529
- Description: The purpose was to establish how foundational provision programmes were implemented in a rural based university in South Africa and implications to student development practices. The study was located in the- post- positivism research paradigm, followed a mixed methods research approach and utilised a concurrent triangulation research design. For the qualitative component of the research, participants (academics and Coordinators of the foundation programmes and senior students who had enrolled through foundational provision programmes) were purposively sampled. The sample for the quantitative data comprised all the students who enrolled in foundation provision programmes between the years 2008 to 2011 and mainstream students who had enrolled between the years 2009 and 2012. For qualitative approach, focus group discussions were conducted, semi-structured interviews and document analysis. Quantitative data was sought from university institutional data storage warehouse, HIGHER EDUCATION MANAGEMENT INFORMATION SYSTEM (HEMIS). For qualitative approach, the data analysis for all data collection methods was done through thematic analysis. For quantitative approach, a longitudinal analysis was conducted to track and compare two cohorts of mainstream and foundation students in terms of retention, attrition and graduation rates. Quantitative data were analysed statistically by use of descriptive and some inferential statistics. Main findings were that: there was inadequate capacity institutionally for developed systems of admission for students entering foundation programmes, lack of curriculum compliance by different lecturers and lack of knowledge of curriculum reforms by lecturers who teach in foundation level, funding for foundation provision programmes was not adequate and lacked transparency. However, there were adequate recruitment processes in the university for lecturers that teach in foundational foundation provision programme and there was no government interference into how foundation programmes are governed. The study also found that students had experienced the student development practices positively, however, these practices were not enough, and equally most responsive student development practice did not exist at the institution under study. The study also found that there had been consistent funding from government but there was no proper expenditure systems in the institution. The study found that, in terms of graduation rates, the two groups compared relatively the same as there was no significant differences in patterns and trends that were observed. However, retention rates suggest that, in the first year, the two groups perform relatively the same, thereafter, there is a significant difference into how the two groups perform as they proceed to other years, especially the second year, where the mainstream cohort showed better performance than their foundation provision programme counterparts. Consequently, high attrition rates were experienced by foundation provision students than mainstream students, this was also experienced a lot more during the second year and third year transition. The implication of these findings was that due to institutional factors that affect the implementation of foundation programmes, these had notable impact on the attrition and dropout rates on foundation provision students. In addition, due to a lack of responsive student development practices, foundation programmes compared relatively low to their mainstream counterparts in retention. The study has recommended a model that can be implemented in the institution. The first component of the model is to put an admission system in place. Institution has to establish a platform where faculties present development plans for foundation provision programmes. In addition, there should be a dedicated Accountant managing finances of the foundation programme. The institution should establish the Tracking and Monitoring student development practice, establish Writing Centres and Learning Communities and employ more people in the Centre for Higher Education, Teaching and Learning department to ensure full implementation of existing student development practices and those that will be established. , Thesis (PhD) -- Faculty of Education, 2016
- Full Text:
- Date Issued: 2016-05
- Authors: Marhaya, Luyanda
- Date: 2016-05
- Subjects: Education, Higher -- South Africa , College student development programs
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24706 , vital:63529
- Description: The purpose was to establish how foundational provision programmes were implemented in a rural based university in South Africa and implications to student development practices. The study was located in the- post- positivism research paradigm, followed a mixed methods research approach and utilised a concurrent triangulation research design. For the qualitative component of the research, participants (academics and Coordinators of the foundation programmes and senior students who had enrolled through foundational provision programmes) were purposively sampled. The sample for the quantitative data comprised all the students who enrolled in foundation provision programmes between the years 2008 to 2011 and mainstream students who had enrolled between the years 2009 and 2012. For qualitative approach, focus group discussions were conducted, semi-structured interviews and document analysis. Quantitative data was sought from university institutional data storage warehouse, HIGHER EDUCATION MANAGEMENT INFORMATION SYSTEM (HEMIS). For qualitative approach, the data analysis for all data collection methods was done through thematic analysis. For quantitative approach, a longitudinal analysis was conducted to track and compare two cohorts of mainstream and foundation students in terms of retention, attrition and graduation rates. Quantitative data were analysed statistically by use of descriptive and some inferential statistics. Main findings were that: there was inadequate capacity institutionally for developed systems of admission for students entering foundation programmes, lack of curriculum compliance by different lecturers and lack of knowledge of curriculum reforms by lecturers who teach in foundation level, funding for foundation provision programmes was not adequate and lacked transparency. However, there were adequate recruitment processes in the university for lecturers that teach in foundational foundation provision programme and there was no government interference into how foundation programmes are governed. The study also found that students had experienced the student development practices positively, however, these practices were not enough, and equally most responsive student development practice did not exist at the institution under study. The study also found that there had been consistent funding from government but there was no proper expenditure systems in the institution. The study found that, in terms of graduation rates, the two groups compared relatively the same as there was no significant differences in patterns and trends that were observed. However, retention rates suggest that, in the first year, the two groups perform relatively the same, thereafter, there is a significant difference into how the two groups perform as they proceed to other years, especially the second year, where the mainstream cohort showed better performance than their foundation provision programme counterparts. Consequently, high attrition rates were experienced by foundation provision students than mainstream students, this was also experienced a lot more during the second year and third year transition. The implication of these findings was that due to institutional factors that affect the implementation of foundation programmes, these had notable impact on the attrition and dropout rates on foundation provision students. In addition, due to a lack of responsive student development practices, foundation programmes compared relatively low to their mainstream counterparts in retention. The study has recommended a model that can be implemented in the institution. The first component of the model is to put an admission system in place. Institution has to establish a platform where faculties present development plans for foundation provision programmes. In addition, there should be a dedicated Accountant managing finances of the foundation programme. The institution should establish the Tracking and Monitoring student development practice, establish Writing Centres and Learning Communities and employ more people in the Centre for Higher Education, Teaching and Learning department to ensure full implementation of existing student development practices and those that will be established. , Thesis (PhD) -- Faculty of Education, 2016
- Full Text:
- Date Issued: 2016-05
Behaviour and trophic ecology of oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) associated with floating objects in the open ocean
- Forget, Fabien Rocky Gilbert
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
- Full Text:
- Date Issued: 2016
- Authors: Forget, Fabien Rocky Gilbert
- Date: 2016
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193531 , vital:45340
- Description: The oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata) are epipelagic species that commonly associate with floating objects throughout the world’s tropical oceans. Besides tunas, these two species often form the bulk of the aggregation and are major non-target species (bycatch) incidentally captured at fish aggregation devices (FADs) by tropical tuna purse seiners. Despite being abundant, little is known about their basic biology, ecology and associative behavior with floating objects. This thesis aims to address knowledge gaps in their associative behavior and ecology at floating objects and attempts to explore potential bycatch mitigation methods. Acoustic telemetry was used to characterise several aspects of the two species’ behavior at floating objects. Fish were captured and tagged at drifting FADs in the core of the western Indian Ocean tuna fishing grounds. Prolonged remote observations were obtained through satellite linked receivers which provided fine-scale data on the behavior of oceanic triggerfish (n= 46 919 cumulated observation days) and rainbow runner (n= 24 538 cumulated observation days). The two species remained associated with the same floating object for periods extending up to several months. The mean residence time estimated using a survival analysis was 65 days for oceanic triggerfish and 94 days for rainbow runner. A distinct diel pattern in association was observed; the two species were closely associated to the FAD during the night and increased their home range during the day while performing short excursions (oceanic triggerfish mean: 2.0 hours ±1.6 SD; rainbow runner mean: 2.4 hours ±2.2 SD) away from the FAD. Similarly, distinct patterns in the vertical movements and locomotory activity (measured using accelerometer tags) were observed as the two species increased their vertical movements and activity levels during the day. Generally, their vertical movements were largely restricted to the mixed layer (< 60 m). At night, the two species remained close to the surface (0-5 m) where they appear to be in a resting state. An interesting behavioural switch in activity levels and vertical distribution was observed for oceanic triggerfish which coincided with a change in the environment as the FAD drifted close to a cold-core cyclonic eddy. Ambient light appears to be the key stimulus triggering the observed diel behavioural patterns. species-specific vulnerability for target species, skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), bigeye tuna (Thunnus obesus) and non-target species, including silky shark (Carcharhinus falciformis), oceanic triggerfish, and rainbow runner, to the purse seine fishing gear were investigated. Hourly presence rates at FADs over 24 hours were examined to assess whether the capture rate of non-target species could be reduced at specific times during the day. Silky sharks displayed a similar associative pattern to that of targeted tunas. Moreover, the vulnerability of both target and non-target species were close to the maximum during the period of behavioural transitions at sunrise when the majority of the fishing sets are made. As such, a change in set time in the western Indian Ocean does not appear to be a feasible method to reduce capture rates of non-target species. Stomach content and stable isotope analysis were conducted on oceanic triggerfish (stomach n = 152, isotope n = 65) and rainbow runner (stomach n = 156, isotope n = 71) incidentally captured individuals at FADs by purse seiners. Typical FAD-associated prey items represented a minor component of their diet as they predominantly foraged on zooplankton and micronekton in the water column, suggesting that oceanic triggerfish and rainbow runner do not associate to floating objects for direct trophic advantages. Overlap in their dietary and isotopic niches indicates an intermediate level of competition. Overall, the spatial and trophic ecology of both species are remarkably similar and prolonged associations with FADs indicates that floating objects play a significant ecological role in the pelagic environment for the two species. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2016
- Full Text:
- Date Issued: 2016
Soil microbial properties and apple tree performance under conventional and organic management
- Authors: Meyer, André Harold
- Date: 2016
- Subjects: Soil management South Africa Western Cape , Agricultural chemicals Environmental aspects , Soil microbiology South Africa Western Cape , Vesicular-arbuscular mycorrhizas , Enzymes Biotechnology , Apples Organic farming South Africa Western Cape
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/64545 , vital:28557
- Description: Conventional (CON) soil management that permits the use of agrochemicals is currently the most common form of management in Western Cape deciduous fruit orchards. There is increasing pressure to minimise or eliminate synthetic agrochemical usage due to its potentially harmful effect on the environment, particularly to non-target soil microorganisms, and to the functions and processes they perform or mediate. In apple orchards, organic (ORG) practices exclude the use of synthetic pesticides and herbicides making use instead of organic fertilisers and naturally derived products as defined by organic certification programs. ORG practices aim to improve nutrient availability, yield, and long-term orchard sustainability relative to CON orchard management practices. If ORG and CON orchard floor management practices affect orchard ecosystems differently, such differences should be measurable in terms of differences in microbiological parameters. In this thesis it is hypothesised that ORG practices would induce positive soil microbiological responses in Western Cape apple orchards relative to CON practices, and by inference general soil health and apple tree performance. To test this hypothesis a polyphasic approach was adopted. This involved measurement of soil microbial activities and functional diversities, by enzyme activity (using colorimetric assays) and carbon-substrate utilisation (using the BIOLOG™ system), respectively. With reference to the enzyme analyses, the performance of a literature-validated, enzyme-based soil health index was also tested. The analyses were supported by coarse-level comparisons of the magnitude of bacteria, fungi, actinobacteria and total heterotroph populations using traditional culturing techniques (dilution plating on growth media). The extent to which the microbial status differed between the applied ORG and CON treatments was thought likely to reflect such treatment-induced variables as soil nutrient status, apple tree nutritional response, tree growth and yield, all of which were determined. Because the root systems of deciduous fruit trees commonly extend to depths >60 cm in well-prepared soils, microbial enzyme activities in the soil depth intervals corresponding to the lower rootzone, were also investigated. This research was carried out in a randomized field trial. Finally, to gain a broader understanding of the effects of contrasting soil management systems on soil microbiology under a greater variety of environmental conditions, arbuscular mycorrhizal (AM) fungal dynamics were explored in a survey of commercial apple orchards. These orchards were selected to span the range of environmental conditions that occur in the apple production areas of the Western Cape. Orchard soils under ORG management promoted richer microbial ecosystems, and appeared to be better able to sustain community metabolic diversity and, by inference, the functions mediated by soil microbial communities, than those under CON management. This implies that ORG approaches possibly afford a better option to sustain critical ecosystem functions than CON management. This possibly explains why use of straw mulches and compost in accordance with ORG practices, compared with CON practices, promoted β-glucosidase, acid phosphatase and urease activities rather than affecting the abundance of the micro-organisms that produce these enzymes. Enzyme activities in the 0–30 cm soil intervals were also more effectively promoted by ORG than CON practices, although no differences were observed at lower depth intervals. ORG practices promoted functional AM associations more effectively than CON practices, but the abundance of glomalin, a beneficial by-product of AM fungi, was unaffected. The greater enzyme activities and higher root colonisation levels in the ORG treatments probably contributed to improved nutritional effects that caused greater vegetative growth, but lower yields, in the ORG treatments. Yield suppression was conceivably due to excessive vegetative growth induced by oversupply of compost and the mineral nutrients contained therein. The survey of Western Cape apple orchards suggested that neither glomalin nor root colonisation bore any specific relationship to production area, cultivation practice, scion x rootstock combination, or, in the case of root colonisation, with any chemical parameters. However, the effect of season on glomalin was conclusively shown, being higher in summer than in spring, as was the lack of any effect of year on glomalin and root colonisation. Collectively, these results showed that ORG soil management promote soil microbiology, soil nutrient status, and apple tree performance compared to CON management. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2016
- Full Text:
- Date Issued: 2016
- Authors: Meyer, André Harold
- Date: 2016
- Subjects: Soil management South Africa Western Cape , Agricultural chemicals Environmental aspects , Soil microbiology South Africa Western Cape , Vesicular-arbuscular mycorrhizas , Enzymes Biotechnology , Apples Organic farming South Africa Western Cape
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/64545 , vital:28557
- Description: Conventional (CON) soil management that permits the use of agrochemicals is currently the most common form of management in Western Cape deciduous fruit orchards. There is increasing pressure to minimise or eliminate synthetic agrochemical usage due to its potentially harmful effect on the environment, particularly to non-target soil microorganisms, and to the functions and processes they perform or mediate. In apple orchards, organic (ORG) practices exclude the use of synthetic pesticides and herbicides making use instead of organic fertilisers and naturally derived products as defined by organic certification programs. ORG practices aim to improve nutrient availability, yield, and long-term orchard sustainability relative to CON orchard management practices. If ORG and CON orchard floor management practices affect orchard ecosystems differently, such differences should be measurable in terms of differences in microbiological parameters. In this thesis it is hypothesised that ORG practices would induce positive soil microbiological responses in Western Cape apple orchards relative to CON practices, and by inference general soil health and apple tree performance. To test this hypothesis a polyphasic approach was adopted. This involved measurement of soil microbial activities and functional diversities, by enzyme activity (using colorimetric assays) and carbon-substrate utilisation (using the BIOLOG™ system), respectively. With reference to the enzyme analyses, the performance of a literature-validated, enzyme-based soil health index was also tested. The analyses were supported by coarse-level comparisons of the magnitude of bacteria, fungi, actinobacteria and total heterotroph populations using traditional culturing techniques (dilution plating on growth media). The extent to which the microbial status differed between the applied ORG and CON treatments was thought likely to reflect such treatment-induced variables as soil nutrient status, apple tree nutritional response, tree growth and yield, all of which were determined. Because the root systems of deciduous fruit trees commonly extend to depths >60 cm in well-prepared soils, microbial enzyme activities in the soil depth intervals corresponding to the lower rootzone, were also investigated. This research was carried out in a randomized field trial. Finally, to gain a broader understanding of the effects of contrasting soil management systems on soil microbiology under a greater variety of environmental conditions, arbuscular mycorrhizal (AM) fungal dynamics were explored in a survey of commercial apple orchards. These orchards were selected to span the range of environmental conditions that occur in the apple production areas of the Western Cape. Orchard soils under ORG management promoted richer microbial ecosystems, and appeared to be better able to sustain community metabolic diversity and, by inference, the functions mediated by soil microbial communities, than those under CON management. This implies that ORG approaches possibly afford a better option to sustain critical ecosystem functions than CON management. This possibly explains why use of straw mulches and compost in accordance with ORG practices, compared with CON practices, promoted β-glucosidase, acid phosphatase and urease activities rather than affecting the abundance of the micro-organisms that produce these enzymes. Enzyme activities in the 0–30 cm soil intervals were also more effectively promoted by ORG than CON practices, although no differences were observed at lower depth intervals. ORG practices promoted functional AM associations more effectively than CON practices, but the abundance of glomalin, a beneficial by-product of AM fungi, was unaffected. The greater enzyme activities and higher root colonisation levels in the ORG treatments probably contributed to improved nutritional effects that caused greater vegetative growth, but lower yields, in the ORG treatments. Yield suppression was conceivably due to excessive vegetative growth induced by oversupply of compost and the mineral nutrients contained therein. The survey of Western Cape apple orchards suggested that neither glomalin nor root colonisation bore any specific relationship to production area, cultivation practice, scion x rootstock combination, or, in the case of root colonisation, with any chemical parameters. However, the effect of season on glomalin was conclusively shown, being higher in summer than in spring, as was the lack of any effect of year on glomalin and root colonisation. Collectively, these results showed that ORG soil management promote soil microbiology, soil nutrient status, and apple tree performance compared to CON management. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2016
- Full Text:
- Date Issued: 2016
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