Reef fish associations with benthic habitats at a remote protected coral reef ecosystem in the Western Indian Ocean-Aldabra Atoll, Seychelles
- Authors: Haupt, Philip
- Date: 2020
- Subjects: Coral reef ecology -- Aldabra Islands (Seychelles) , Reef fishes -- Aldabra Islands (Seychelles) , Benthic animals -- Aldabra Islands (Seychelles)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/141629 , vital:37991
- Description: The aim of the thesis is to develop an understanding of the associations between reef fish and benthic habitats and assess the modifying effects of environmental processes on these relationships at Aldabra, a pristine atoll in the Western Indian Ocean (WIO). Conducting research in pristine, or reference coral reef ecosystem, removes the impact of direct anthropogenic disturbances and provides essential information on natural ecosystem structure and functioning. Three primary hypotheses were tested: 1) Environmental drivers such as depth and exposure to wave energy determine the spatial distribution of benthic habitats; 2) The reef fish assemblage structure is explained by habitat at multiple scales and modified by the effects of environmental drivers such as depth, wave energy and cyclical temporal drivers such as time and tides; 3) The reef fish assemblage at Aldabra represents a pristine reef fish assemblage, comprising high levels of herbivores and predators. The research focussed on the benthic habitat on the seaward reefs between the shoreline and 50 m depth. The first objective was to characterise the benthic habitats on Aldabra Atoll’s seaward reefs and map their spatial distributions using remotely sensed imagery and ground truthing data. The second was to assess the influence of depth and exposure to wave energy on the distribution of benthic habitats. The third was to identify the most suitable standardised method to survey the reef fish assemblage structure on Aldabra’s, and fourth to determine the effect of tide and time of day on the reef fish assemblage. The fifth objective was to establish the association between reef fish assemblage structure and benthic habitats and to test how species-size influenced the scale of habitat at which the associations were most apparent. Four categories of geomorphic reef zones (reef flats (19.2 km2), top of the forereef slope (7.8 km2), deep forereef slope (11.6 km2), and reef platform (14.3 km2)) were manually delineated following the visual outlines of reef features from satellite imagery. The six broad-scale and twelve fine-scale benthic habitats were mapped using a supervised maximum likelihood classification and the spatial coverage of each determined. The broad-scale habitats were 1) Epilithic algal matrix, 2) Hard and soft (coral, 3) Rubble, 4) Macroalgae, 5) Seagrass and 6) Sand. Similarly, twelve fine-scale benthic habitats were characterised and mapped, for example, Hard coral (19 %) including massive and submassive forms with Millepora and Rhytisma. The broad-scale benthic habitat map had an overall producer accuracy of 54 % and fine-scale habitat map 29 %, which was consistent with studies using similar habitat classification methods. The prevailing wave energy, depth and the directional orientation of coral reefs (aspect) significantly influenced the probability of occurrence of each of the broad-scale benthic habitats, and there was a shift in peak probability of occurrence of all habitat categories to a greater depth with an increase in wave energy. The strong relationship of benthic habitats with depth and wave energy suggests that the distributions of benthic habitats are likely to change with sea-level rise and increased intensity and frequency of storms in future. Overall, 338 fish species from 51 families, including 14 species of elasmobranch were recorded using Baited Remote Underwater Video systems (BRUVs) and unbaited Remote Underwater Video systems (RUVS) from 231 samples. Fish were significantly more abundant when observed using BRUVs (119 ± 7) relative to RUVs (92 ± 7), and the assemblage structures were significantly different between the two sampling methods. Abundance and species richness of generalist carnivores and piscivores were significantly greater in BRUVs, while RUVs recorded significantly greater numbers of herbivores and more species of herbivore and corallivore. The results suggest that BRUVs are better suited when studying predatory fish which may not be detected without bait. However, when surveying a taxonomically and functionally diverse assemblage of fishes at a pristine reef, RUVs may provide a more accurate estimate of natural reef fish assemblage structure. Reef fish assemblages observed using RUVs were significantly different between morning-high-tide, midday-low-tide and evening-high-tide for all trophic groups. However, the reef fish assemblage structure observed using BRUVs was insensitive to change in tide and time of day, which may be explained by the attraction effect of bait dampening the effect of tide and time of day. While RUVs appear better to detect more subtle variations in fish assemblage structure, care needs to be taken when designing research programmes that use RUVs, as the sampling design should account for tide and time of day to avoid misinterpreting the cyclical variation, which may confound results. Reef fish assemblages were significantly different among habitats within geomorphic reef zones, broad-scale and fine-scale habitats. Species turnover rates were significantly different for all Actinopterygii size-class categories between the three scales of habitat. No marked differences in species turnover rates among habitats were detected for the majority of Elasmobranch size-class categories. The strong habitat dependency over various spatial scales indicates that effective conservation of Actinopterygii fish at Aldabra, and elsewhere in similar ecosystems requires protection of representative sets of benthic habitats. However, Elasmobranch conservation requires sufficiently large areas as these species utilise multiple habitats, over multiple scales, which are likely to exceed the confines of Aldabra’s reef.
- Full Text:
- Date Issued: 2020
- Authors: Haupt, Philip
- Date: 2020
- Subjects: Coral reef ecology -- Aldabra Islands (Seychelles) , Reef fishes -- Aldabra Islands (Seychelles) , Benthic animals -- Aldabra Islands (Seychelles)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/141629 , vital:37991
- Description: The aim of the thesis is to develop an understanding of the associations between reef fish and benthic habitats and assess the modifying effects of environmental processes on these relationships at Aldabra, a pristine atoll in the Western Indian Ocean (WIO). Conducting research in pristine, or reference coral reef ecosystem, removes the impact of direct anthropogenic disturbances and provides essential information on natural ecosystem structure and functioning. Three primary hypotheses were tested: 1) Environmental drivers such as depth and exposure to wave energy determine the spatial distribution of benthic habitats; 2) The reef fish assemblage structure is explained by habitat at multiple scales and modified by the effects of environmental drivers such as depth, wave energy and cyclical temporal drivers such as time and tides; 3) The reef fish assemblage at Aldabra represents a pristine reef fish assemblage, comprising high levels of herbivores and predators. The research focussed on the benthic habitat on the seaward reefs between the shoreline and 50 m depth. The first objective was to characterise the benthic habitats on Aldabra Atoll’s seaward reefs and map their spatial distributions using remotely sensed imagery and ground truthing data. The second was to assess the influence of depth and exposure to wave energy on the distribution of benthic habitats. The third was to identify the most suitable standardised method to survey the reef fish assemblage structure on Aldabra’s, and fourth to determine the effect of tide and time of day on the reef fish assemblage. The fifth objective was to establish the association between reef fish assemblage structure and benthic habitats and to test how species-size influenced the scale of habitat at which the associations were most apparent. Four categories of geomorphic reef zones (reef flats (19.2 km2), top of the forereef slope (7.8 km2), deep forereef slope (11.6 km2), and reef platform (14.3 km2)) were manually delineated following the visual outlines of reef features from satellite imagery. The six broad-scale and twelve fine-scale benthic habitats were mapped using a supervised maximum likelihood classification and the spatial coverage of each determined. The broad-scale habitats were 1) Epilithic algal matrix, 2) Hard and soft (coral, 3) Rubble, 4) Macroalgae, 5) Seagrass and 6) Sand. Similarly, twelve fine-scale benthic habitats were characterised and mapped, for example, Hard coral (19 %) including massive and submassive forms with Millepora and Rhytisma. The broad-scale benthic habitat map had an overall producer accuracy of 54 % and fine-scale habitat map 29 %, which was consistent with studies using similar habitat classification methods. The prevailing wave energy, depth and the directional orientation of coral reefs (aspect) significantly influenced the probability of occurrence of each of the broad-scale benthic habitats, and there was a shift in peak probability of occurrence of all habitat categories to a greater depth with an increase in wave energy. The strong relationship of benthic habitats with depth and wave energy suggests that the distributions of benthic habitats are likely to change with sea-level rise and increased intensity and frequency of storms in future. Overall, 338 fish species from 51 families, including 14 species of elasmobranch were recorded using Baited Remote Underwater Video systems (BRUVs) and unbaited Remote Underwater Video systems (RUVS) from 231 samples. Fish were significantly more abundant when observed using BRUVs (119 ± 7) relative to RUVs (92 ± 7), and the assemblage structures were significantly different between the two sampling methods. Abundance and species richness of generalist carnivores and piscivores were significantly greater in BRUVs, while RUVs recorded significantly greater numbers of herbivores and more species of herbivore and corallivore. The results suggest that BRUVs are better suited when studying predatory fish which may not be detected without bait. However, when surveying a taxonomically and functionally diverse assemblage of fishes at a pristine reef, RUVs may provide a more accurate estimate of natural reef fish assemblage structure. Reef fish assemblages observed using RUVs were significantly different between morning-high-tide, midday-low-tide and evening-high-tide for all trophic groups. However, the reef fish assemblage structure observed using BRUVs was insensitive to change in tide and time of day, which may be explained by the attraction effect of bait dampening the effect of tide and time of day. While RUVs appear better to detect more subtle variations in fish assemblage structure, care needs to be taken when designing research programmes that use RUVs, as the sampling design should account for tide and time of day to avoid misinterpreting the cyclical variation, which may confound results. Reef fish assemblages were significantly different among habitats within geomorphic reef zones, broad-scale and fine-scale habitats. Species turnover rates were significantly different for all Actinopterygii size-class categories between the three scales of habitat. No marked differences in species turnover rates among habitats were detected for the majority of Elasmobranch size-class categories. The strong habitat dependency over various spatial scales indicates that effective conservation of Actinopterygii fish at Aldabra, and elsewhere in similar ecosystems requires protection of representative sets of benthic habitats. However, Elasmobranch conservation requires sufficiently large areas as these species utilise multiple habitats, over multiple scales, which are likely to exceed the confines of Aldabra’s reef.
- Full Text:
- Date Issued: 2020
Resource recovery options in brewery effluent treatment using activated sludge and high rate algal ponds: assessing environmental impacts
- Authors: Taylor, Richard Peter
- Date: 2020
- Subjects: Sewage -- Purification -- Activated sludge process , Sewage disposal plants , Sewage -- Purification -- Biological treatament , Sewage -- Purification -- Nitrogen removal , Brewery waste , Breweries -- Waste disposal , Microalgae -- Biotechnology , Algal biofuels
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/153746 , vital:39507
- Description: Wastewater treatment plants (WWTPs) are designed to clean effluents, but they also consume resources and produce waste. Various treatment technologies allow for the recovery of energy, nutrients and water from effluents turning this waste into products, which increases their sustainability and decreases the impact of WWTPs on the environment. There is a lack of literature which comprehensively compares the treatment performances, environmental impacts and beneficial downstream uses of the biomass generated by high rate algal pond (HRAP) and activated sludge (AS) treatment systems. This thesis aimed to compare (1) effluent treatment performance, (2) emissions and (3) downstream use of algae cultured in HRAP to sludge produced in AS and to obtain data to conduct a life cycle analysis (LCA) to compare the systems. The focus was on adding value to the effluent treatment process, while identifying the associated environmental impacts and contributing to the first ever zero-waste brewery effluent treatment system. Furthermore, these data were used to provide a basis to critically review and contribute to improving the methods used in the LCA of effluent treatment systems; particularly since this was the first wastewater treatment LCA that compared AS and HRAP using data collected from the same temporal and geographic location and from a single effluent stream. The electrical consumption water emission and land application of waste biomass caused the major environmental impacts of both treatment systems. The HRAP had less than 50 % of the electrical energy consumption (0.11±0.01 kW/m3 of effluent treated) compared to the AS system (0.29±0.11 kW/m3) which resulted in the technology having a lower climate change, photochemical oxidant formation, freshwater and marine ecotoxicity and fossil fuel depletion impact. It is imperative to understand the method of electrical energy (fossil fuel vs renewable) generation when conducting a LCA and deciding which technologies to use, since they have a major influence on the aforementioned impacts. The biogas yield of algal and sludge substrates was similar with an average gas production of 241 ml/g volatile solids fed. Biogas from algae fed digesters had a significantly higher methane content (64.73±0.81 %) and lower carbon dioxide content (22.94±0.24 %) when compared to WAS fed digesters (60.08±0.18 % and 27.37±0.43 %) respectively due to it being a less oxidised substrate. Swiss chard plants (Beta vulgaris) fertilised with anaerobically digested (AD) algae or sludge had a significantly higher mean biweekly yield (5.08±0.73 kg/m2) when compared to the inorganic-fertiliser control (3.45±0.89 kg/m2; p<0.0001). No difference was observed in the soil’s physical fertility when algae or sludge were applied to the soil (p>0.05). The HRAP produced more biomass (317.18±27.76 g/m3) than the AS (83.12±64.91 g/m3), which resulted in a significantly greater downstream production of biogas and fertiliser per volume of effluent treated. According to the LCA, this also resulted in the HRAP system having a higher terrestrial ecotoxicity, due to the greater volume of solids and thus heavy metals applied to the soil. This interpretation can be misleading, because the mass of heavy metals released into the environment is the same for both systems, with a greater portion being applied to the land in the HRAP scenario and discharged into fresh water in the case of AS. Future LCA models should clarify if these biomasses are going to be applied to a single piece of land or multiple sites as this will influence the risk of contamination via pollutant build up in the soil. The application of sludge or algae on soil increased the soil’s sodium concentration and sodium absorption ratio from 774.80±13.66 mg/kg to 952.17±34.89 mg/kg and 2.91±0.04 to 3.53±0.13, respectively. Regulations on the application of algae or sludge on agricultural soils should be altered to consider the limit values for sodium and future LCA’s associated with effluent treatment facilities should incorporate the possibility of soil contamination through sodium build-up. This work also conceptualised the importance of reporting water emissions in wastewater treatment LCA in as much detail as possible, because this had a significant influence on the eutrophication impacts on water systems. Reporting water emissions as total nitrogen underestimated downstream eutrophication impacts compared with those using nitrogen-species concentration (ammonia, nitrite, nitrate etc). A marine eutrophication sensitivity co-efficient should be included in future LCA models which accounts for the probability of nitrogen and phosphorus emissions entering the coastal environment as well as the vulnerability of the marine environment to eutrophication. Activated sludge systems are favourable for situations where space is limited, were there are inadequate options for biomass disposal (biomass not be used in agriculture or AD) and were electricity is generated from a renewable source; whereas, HRAP are more suitable under circumstances where electricity production relies on fossil fuel that carries a high environmental impact and where options are available to use the biomass for economic gain such as biogas and fertiliser production. This thesis contributes towards a zero-waste brewery effluent treated process. The HRAP and AS treated effluent for reuse in the brewery or in agricultural irrigation. The solids were anaerobically digested, and the carbon was recovered as a biogas, while the digestate was applied as an agricultural fertiliser. This allowed for the recovery of water, nutrients and carbon.
- Full Text:
- Date Issued: 2020
- Authors: Taylor, Richard Peter
- Date: 2020
- Subjects: Sewage -- Purification -- Activated sludge process , Sewage disposal plants , Sewage -- Purification -- Biological treatament , Sewage -- Purification -- Nitrogen removal , Brewery waste , Breweries -- Waste disposal , Microalgae -- Biotechnology , Algal biofuels
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/153746 , vital:39507
- Description: Wastewater treatment plants (WWTPs) are designed to clean effluents, but they also consume resources and produce waste. Various treatment technologies allow for the recovery of energy, nutrients and water from effluents turning this waste into products, which increases their sustainability and decreases the impact of WWTPs on the environment. There is a lack of literature which comprehensively compares the treatment performances, environmental impacts and beneficial downstream uses of the biomass generated by high rate algal pond (HRAP) and activated sludge (AS) treatment systems. This thesis aimed to compare (1) effluent treatment performance, (2) emissions and (3) downstream use of algae cultured in HRAP to sludge produced in AS and to obtain data to conduct a life cycle analysis (LCA) to compare the systems. The focus was on adding value to the effluent treatment process, while identifying the associated environmental impacts and contributing to the first ever zero-waste brewery effluent treatment system. Furthermore, these data were used to provide a basis to critically review and contribute to improving the methods used in the LCA of effluent treatment systems; particularly since this was the first wastewater treatment LCA that compared AS and HRAP using data collected from the same temporal and geographic location and from a single effluent stream. The electrical consumption water emission and land application of waste biomass caused the major environmental impacts of both treatment systems. The HRAP had less than 50 % of the electrical energy consumption (0.11±0.01 kW/m3 of effluent treated) compared to the AS system (0.29±0.11 kW/m3) which resulted in the technology having a lower climate change, photochemical oxidant formation, freshwater and marine ecotoxicity and fossil fuel depletion impact. It is imperative to understand the method of electrical energy (fossil fuel vs renewable) generation when conducting a LCA and deciding which technologies to use, since they have a major influence on the aforementioned impacts. The biogas yield of algal and sludge substrates was similar with an average gas production of 241 ml/g volatile solids fed. Biogas from algae fed digesters had a significantly higher methane content (64.73±0.81 %) and lower carbon dioxide content (22.94±0.24 %) when compared to WAS fed digesters (60.08±0.18 % and 27.37±0.43 %) respectively due to it being a less oxidised substrate. Swiss chard plants (Beta vulgaris) fertilised with anaerobically digested (AD) algae or sludge had a significantly higher mean biweekly yield (5.08±0.73 kg/m2) when compared to the inorganic-fertiliser control (3.45±0.89 kg/m2; p<0.0001). No difference was observed in the soil’s physical fertility when algae or sludge were applied to the soil (p>0.05). The HRAP produced more biomass (317.18±27.76 g/m3) than the AS (83.12±64.91 g/m3), which resulted in a significantly greater downstream production of biogas and fertiliser per volume of effluent treated. According to the LCA, this also resulted in the HRAP system having a higher terrestrial ecotoxicity, due to the greater volume of solids and thus heavy metals applied to the soil. This interpretation can be misleading, because the mass of heavy metals released into the environment is the same for both systems, with a greater portion being applied to the land in the HRAP scenario and discharged into fresh water in the case of AS. Future LCA models should clarify if these biomasses are going to be applied to a single piece of land or multiple sites as this will influence the risk of contamination via pollutant build up in the soil. The application of sludge or algae on soil increased the soil’s sodium concentration and sodium absorption ratio from 774.80±13.66 mg/kg to 952.17±34.89 mg/kg and 2.91±0.04 to 3.53±0.13, respectively. Regulations on the application of algae or sludge on agricultural soils should be altered to consider the limit values for sodium and future LCA’s associated with effluent treatment facilities should incorporate the possibility of soil contamination through sodium build-up. This work also conceptualised the importance of reporting water emissions in wastewater treatment LCA in as much detail as possible, because this had a significant influence on the eutrophication impacts on water systems. Reporting water emissions as total nitrogen underestimated downstream eutrophication impacts compared with those using nitrogen-species concentration (ammonia, nitrite, nitrate etc). A marine eutrophication sensitivity co-efficient should be included in future LCA models which accounts for the probability of nitrogen and phosphorus emissions entering the coastal environment as well as the vulnerability of the marine environment to eutrophication. Activated sludge systems are favourable for situations where space is limited, were there are inadequate options for biomass disposal (biomass not be used in agriculture or AD) and were electricity is generated from a renewable source; whereas, HRAP are more suitable under circumstances where electricity production relies on fossil fuel that carries a high environmental impact and where options are available to use the biomass for economic gain such as biogas and fertiliser production. This thesis contributes towards a zero-waste brewery effluent treated process. The HRAP and AS treated effluent for reuse in the brewery or in agricultural irrigation. The solids were anaerobically digested, and the carbon was recovered as a biogas, while the digestate was applied as an agricultural fertiliser. This allowed for the recovery of water, nutrients and carbon.
- Full Text:
- Date Issued: 2020
Synthesis, characterisation and electrocatalytic behaviour of three series of Metal Organic Frameworks
- Authors: Murinzi, Tafadzwa Wendy
- Date: 2020
- Subjects: Electrochemistry , Metal-organic frameworks , Polyoxometalates , Fourier transform infrared spectroscopy , Electrocatalysis , Cysteine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167598 , vital:41495
- Description: Metal organic frameworks (MOFs) have received a lot of attention over the past few years due to their vast range of interesting properties and applications, such as catalysis, environmental sensing and storage. This wide range of potential applications is afforded by careful selection and manipulation of the components chosen in assembling of MOFs. In this study, three series of MOFs were synthesized from Co(II), Cu(II) and Mo(VI) polyoxometallates with either 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid or 2,6- pyridinedicarboxylic acid as the ligands. In series 1, the common 1,3,5- benzenetricarboxylic acid MOF, HKUST-1, and POM modified HKUST-1 compounds involving encapsulation and encorporation of the POM were utilised. In series 2, flexible cobalt(II) benzenepolycarboxylate MOFs which investigated the effect of varying the degree of carboxylate substituent were utilised. In series 3, flexibly reduced heterocyclic polycarboxylate MOFs using 2,6-pyridine dicarboxylate were utilised. Solvothermal and slow evaporation synthesis conditions were employed. Where single crystals of good quality were produced, single crystal X-ray diffraction (SC-XRD) was employed for structural elucidation. In the absence of such crystals, a combination of elemental analysis, inductively coupled plasma optical emission spectrometry (ICP-OES) and powder X-ray diffraction (PXRD) was used. Characterization of the MOFs was done by Fourier transform infrared spectrometry (FTIR) and thermal methods, namely thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrocatalytic potential of the compounds in the oxidation of L-cysteine was then investigated using a variety of techniques. Cyclic voltammetry was used for L-cysteine detection whilst chronoamperometry and differential pulse voltammetry were used to determine the nanoprobes’ sensitivity, rate constants and detection limits. Electrochemical impedence spectroscopy was used to investigate the charge transfer resistance (RCT) and electron transfer kinetics. Of the three, series 3 gave the best signals and sensitivities for electrocatalysis of L-cysteine followed by series 2 and lastly series 1. Series 2 showed the highest stability and series 1 required the least overpotential. The results highlight the effects of different metal centres and ligands on electrocatalysis. The application of MOFs in electrochemistry is a relatively new field making the findings of this study a significant addition to the body of knowledge.
- Full Text:
- Date Issued: 2020
- Authors: Murinzi, Tafadzwa Wendy
- Date: 2020
- Subjects: Electrochemistry , Metal-organic frameworks , Polyoxometalates , Fourier transform infrared spectroscopy , Electrocatalysis , Cysteine
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167598 , vital:41495
- Description: Metal organic frameworks (MOFs) have received a lot of attention over the past few years due to their vast range of interesting properties and applications, such as catalysis, environmental sensing and storage. This wide range of potential applications is afforded by careful selection and manipulation of the components chosen in assembling of MOFs. In this study, three series of MOFs were synthesized from Co(II), Cu(II) and Mo(VI) polyoxometallates with either 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid or 2,6- pyridinedicarboxylic acid as the ligands. In series 1, the common 1,3,5- benzenetricarboxylic acid MOF, HKUST-1, and POM modified HKUST-1 compounds involving encapsulation and encorporation of the POM were utilised. In series 2, flexible cobalt(II) benzenepolycarboxylate MOFs which investigated the effect of varying the degree of carboxylate substituent were utilised. In series 3, flexibly reduced heterocyclic polycarboxylate MOFs using 2,6-pyridine dicarboxylate were utilised. Solvothermal and slow evaporation synthesis conditions were employed. Where single crystals of good quality were produced, single crystal X-ray diffraction (SC-XRD) was employed for structural elucidation. In the absence of such crystals, a combination of elemental analysis, inductively coupled plasma optical emission spectrometry (ICP-OES) and powder X-ray diffraction (PXRD) was used. Characterization of the MOFs was done by Fourier transform infrared spectrometry (FTIR) and thermal methods, namely thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrocatalytic potential of the compounds in the oxidation of L-cysteine was then investigated using a variety of techniques. Cyclic voltammetry was used for L-cysteine detection whilst chronoamperometry and differential pulse voltammetry were used to determine the nanoprobes’ sensitivity, rate constants and detection limits. Electrochemical impedence spectroscopy was used to investigate the charge transfer resistance (RCT) and electron transfer kinetics. Of the three, series 3 gave the best signals and sensitivities for electrocatalysis of L-cysteine followed by series 2 and lastly series 1. Series 2 showed the highest stability and series 1 required the least overpotential. The results highlight the effects of different metal centres and ligands on electrocatalysis. The application of MOFs in electrochemistry is a relatively new field making the findings of this study a significant addition to the body of knowledge.
- Full Text:
- Date Issued: 2020
Temporal patterns and seasonal variation in microplastic loads in the water column and in the tissues of consumers along the southern and south-eastern coasts of South Africa
- Authors: Redelinghuys, Suzanne
- Date: 2020
- Subjects: Microplastics -- South Africa -- Eastern Cape , Plastic marine debris -- South Africa -- Eastern Cape , Marine pollution -- South Africa -- Eastern Cape , Ocean circulation -- South Africa -- Eastern Cape , Marine invertebrates -- Effect of pollution on -- South Africa -- Eastern Cape , Marine animals -- Effect of pollution on -- South Africa -- Eastern Cape , Mexilhao mussel -- Effect of pollution on -- South Africa -- Eastern Cape , Mytilus galloprovincialis -- Effect of pollution on -- South Africa -- Eastern Cape , Barnacles -- Effect of pollution on -- South Africa -- Eastern Cape , Tetraclita -- Effect of pollution on -- South Africa -- Eastern Cape , Octomeris angulosa -- Effect of pollution on -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115623 , vital:34201
- Description: Plastic pollution in the marine environment has become an environmental concern and a subject of ecological research. The field of microplastic pollution in particular has expanded dramatically in the last few years. Though much data exists on the spatial variability of microplastics in the marine environment globally, little is known about temporal variability, especially on short-term time scales in the southern hemisphere. Similarly, virtually nothing is known about the temporal patterns in microplastic ingestion by marine invertebrates, despite the fact that numerous studies have demonstrated that vertebrates and invertebrates routinely ingest microplastics with varied physiological effects. This study aimed to, 1) provide base-line data for microplastic loads in the nearshore environment along the Eastern Cape Province of South Africa over four short-term time scales: daily, weekly, monthly, and yearly; and, 2) assess whether there are any seasonal patterns in microplastics ingested by selected filter-feeding consumers at two sites along the southern and south-eastern Cape coastlines of South Africa. Results for part one of this study demonstrate no temporal patterns over the different time scales considered (ANOVA, p > 0.05 in all cases). Microplastic counts ranged on average from 55 ± 289 to 930 ± 462 microplastic particles.m-3. With the exception of two instances, microfibres constituted > 50 % (range: 47 to 97 %) of the total microplastic counts. Part two of this study assessed the size range of, and seasonal and spatial patterns in ingested microplastic. No significant differences were found in the number of microplastics ingested within seasons between the mussels Perna perna (Linnaeus, 1758) and Mytilus galloprovincialis (Lamarck, 1819), and the barnacles, Octomeris angulosa (Sowerby, 1825) and Tetraclita serrata (Darwin 1954) (Student’s t-test; d.f = 18; p > 0.05 in all cases), or between the two sites sampled, Kenton-on-Sea, Eastern Cape, and Wilderness, Western Cape (ANOVA; d.f. = 18; p > 0.05 in all cases). The nitric acid digestion technique was used to determine the presence of ingested microplastics. Microplastic loads ranged from 2 ± 1 to 33 ± 19 microplastics.g-1 wwt across all consumers, and the size of ingested microplastics ranged from 1 to 16 μm. Though highly variable, the absence of statistically significant differences in ingestion rates points to a ubiquity in the availability of microplastics within the water column over time and space.
- Full Text:
- Date Issued: 2020
- Authors: Redelinghuys, Suzanne
- Date: 2020
- Subjects: Microplastics -- South Africa -- Eastern Cape , Plastic marine debris -- South Africa -- Eastern Cape , Marine pollution -- South Africa -- Eastern Cape , Ocean circulation -- South Africa -- Eastern Cape , Marine invertebrates -- Effect of pollution on -- South Africa -- Eastern Cape , Marine animals -- Effect of pollution on -- South Africa -- Eastern Cape , Mexilhao mussel -- Effect of pollution on -- South Africa -- Eastern Cape , Mytilus galloprovincialis -- Effect of pollution on -- South Africa -- Eastern Cape , Barnacles -- Effect of pollution on -- South Africa -- Eastern Cape , Tetraclita -- Effect of pollution on -- South Africa -- Eastern Cape , Octomeris angulosa -- Effect of pollution on -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115623 , vital:34201
- Description: Plastic pollution in the marine environment has become an environmental concern and a subject of ecological research. The field of microplastic pollution in particular has expanded dramatically in the last few years. Though much data exists on the spatial variability of microplastics in the marine environment globally, little is known about temporal variability, especially on short-term time scales in the southern hemisphere. Similarly, virtually nothing is known about the temporal patterns in microplastic ingestion by marine invertebrates, despite the fact that numerous studies have demonstrated that vertebrates and invertebrates routinely ingest microplastics with varied physiological effects. This study aimed to, 1) provide base-line data for microplastic loads in the nearshore environment along the Eastern Cape Province of South Africa over four short-term time scales: daily, weekly, monthly, and yearly; and, 2) assess whether there are any seasonal patterns in microplastics ingested by selected filter-feeding consumers at two sites along the southern and south-eastern Cape coastlines of South Africa. Results for part one of this study demonstrate no temporal patterns over the different time scales considered (ANOVA, p > 0.05 in all cases). Microplastic counts ranged on average from 55 ± 289 to 930 ± 462 microplastic particles.m-3. With the exception of two instances, microfibres constituted > 50 % (range: 47 to 97 %) of the total microplastic counts. Part two of this study assessed the size range of, and seasonal and spatial patterns in ingested microplastic. No significant differences were found in the number of microplastics ingested within seasons between the mussels Perna perna (Linnaeus, 1758) and Mytilus galloprovincialis (Lamarck, 1819), and the barnacles, Octomeris angulosa (Sowerby, 1825) and Tetraclita serrata (Darwin 1954) (Student’s t-test; d.f = 18; p > 0.05 in all cases), or between the two sites sampled, Kenton-on-Sea, Eastern Cape, and Wilderness, Western Cape (ANOVA; d.f. = 18; p > 0.05 in all cases). The nitric acid digestion technique was used to determine the presence of ingested microplastics. Microplastic loads ranged from 2 ± 1 to 33 ± 19 microplastics.g-1 wwt across all consumers, and the size of ingested microplastics ranged from 1 to 16 μm. Though highly variable, the absence of statistically significant differences in ingestion rates points to a ubiquity in the availability of microplastics within the water column over time and space.
- Full Text:
- Date Issued: 2020
The current role of palm species Hyphaene Coriacea and Phoenix Reclanata in local livelihoods in the Zitundo area, southern Mozambique
- Authors: Martins, Angelina R O
- Date: 2020
- Subjects: Ilala palm -- Economic aspects -- Mozambique , Palms -- Economic aspects -- Mozambique , Non-timber forest products industry -- Mozambique , Sustainable development -- Mozambique , Conservation of natural resources -- Mozambique
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150613 , vital:38989
- Description: The majority of rural households in developing countries are heavily dependent on non-timber forest products (NTFPs) to fulfill much of their basic daily needs. In Mozambique more than 64% of the population lives in rural areas and depends heavily in the extraction of NTFPs to complement agricultural production. One substantial source of NTFPs are palm species. Palms are sources of food, building materials, cloth, ornaments, medicines, and are also used for cultural purposes. In southern Mozambique two important palms species used as NTFPs are Hyphaene coriacea and Phoenix reclinata. These two species provide an array of subsistence and commercial products. The sap, leaves and stems of these two palms are harvested by local people as sources of traditional beverages, weaving, roofing, fencing and furniture material as well as other household utensils. The effects (if any) of harvesting of these palm products on palm distribution, population structure, dynamics and viability have never been examined, and thus the sustainability of the practices and benefits flows to local livelihoods are unknow-n. Any effects harvesting effects may also be exacerbated by predicted climate change for the area. The present study aims to investigate the role of the palm species Hyphaene coriacea and Phoenix reclinata in the livelihoods of households in the Zitundo area, Matutuine district, southern Mozambique and under future climate scenarios. Specifically, this study: i) evaluates the abundance, population structure and harvesting selection of these species; ii) characterizes the ethnobotanical knowledge and use of the two species; iii) examines the local production and trade of palm wine in the area; iv) examines the contribution of palm income to livelihoods and income diversification in area; v) describes the local management practices and perceptions on palm productivity and abundance; and vi) models the current and future distribution of the these palm species in the area. To evaluate the abundance, population structure and stability of these two palm species a population census was carried out, and the size class distribution, Simpson index of dominance, permutation index and the quotient between successive size classes were calculated. I further calculated the preference ratio for specific size classes. Additionally a questionnaire survey was conducted with 179 randomly selected households from the 16 villages in the study area to characterize the ethnobotanical knowledge and use of these two species, as well as to examine the contribution of palm income to livelihoods and diversification. Standard ethnobotanical indices were used as measures of each palm species use and knowledge while principal component analysis and cluster analysis were applied to highlight the livelihood patterns and the role of diversification and of palm income in local livelihoods. Structured interviews with 37 palm tappers were additionally used to examine the local production and trade of palm wine in the area, while both the household survey and palm tappers interviews, were employed to investigate the local management practices and perceptions on palms productivity and abundance. Maxent Software was used to model the current and future under climate change distribution of the two palm species. Hyphaene coriacea was more abundant than Phoenix reclinata. Both species exhibited steep negative slopes in the regression analyses of size class distribution, indicating the presence of more individuals in shorter size classes. Although there was a dominance of shorter over taller size classes, limited recruitment was observed through low stem densities of seedlings and juveniles compared to the 1-50 cm size class The Simpson index of dominance, the permutation index, and the fluctuating quotients between the consecutive size classes showed a level of instability in both populations. Hyphaene coriacea appeared to be more resilient to tapping than Phoenix reclinata as showed by the higher rate of stem survival after tapping. Hyphaene coriacea was favored for tapping compared to Phoenix reclinata. The most preferred size class to tap for both species was between 101cm and 150 cm. Currently the distribution of Hyphaene coriacea and Phoenix reclinata was mostly confined to the eastern side of the study area. Most of the area was predicted as unsuitable for both palm species, with less than six percent predicted to be suitable or higher. The occurrence of both species appeared to be influenced mostly by water related variables, such as precipitation, and distance to rivers and distance to water bodies. The habitat suitability for Hyphaene coriacea was predicted to increase under future climate conditions scenarios, while little variation was predicted for Phoenix reclinata distribution. The knowledge about the uses of these two palm species was widespread in the area, although only 32% of respondents were engaged in palm exploitation. Thirteen palm products were exploited, with palm wine production from the sap of both palms being the dominant activity, followed by broom production from Phoenix reclinata stems and basket production from Hyphaene coriacea leaves. The cultural importance of these species included the production of anklets and skirts used during traditional dances and the use of palm wine in the traditional ritual of libation. Palm tapping was practiced year round in five of the sixteen villages in the area. Palm tapping was an important livelihood activity, contributing over 80% of tappers’ total annual income, and tappers earned up to three times more than the national minimum wage for the agricultural and forestry sector. Palm wine was also a highly commercial commodity in Zitundo area, with an average commercialization index above 60%. The income from palm wine sales showed an important role in mitigating the level of poverty in the area. Palm income accounted for over 60% reduction on poverty incidence among palm tappers. Households in Zitundo further engaged in some level of livelihood diversification. The majority of households adopted a wage-based strategy, although this strategy was among the less remunerative in terms of per capita cash income. A palm-based livelihood strategy, although adopted only by 11% of households, was one of the most remunerative strategies. Palm income played a vital role in enhancing household livelihoods and mitigating poverty in the area as shown by the lower poverty incidences among households engaged in the palm-based livelihood strategy than alternatives strategies. The village of household residency, along with household demographic and socio-economic characteristics appeared to determine the knowledge and exploitation level of palms as well as a households’ choice of livelihood strategy, level of palm wine returns, commercialization index and palm income dependency. The importance of palms in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area. Palm wine, broom and basket production have a high potential for income generation, and therefore should be included in future local development policies and poverty reduction strategies. Although palms are an open access resource in Zitundo area, the perception is that they are abundant and that tapping does not have many detrimental effects. However, this study found some negative impacts of tapping on the recruitment of both palms species. The inclusion of palm products in future development programs and poverty reduction strategies will require the design of participatory conservation and management strategies that involve all palm users groups and others stakeholders and include long-term participatory monitoring of the effect of palm use on the populations.
- Full Text:
- Date Issued: 2020
- Authors: Martins, Angelina R O
- Date: 2020
- Subjects: Ilala palm -- Economic aspects -- Mozambique , Palms -- Economic aspects -- Mozambique , Non-timber forest products industry -- Mozambique , Sustainable development -- Mozambique , Conservation of natural resources -- Mozambique
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150613 , vital:38989
- Description: The majority of rural households in developing countries are heavily dependent on non-timber forest products (NTFPs) to fulfill much of their basic daily needs. In Mozambique more than 64% of the population lives in rural areas and depends heavily in the extraction of NTFPs to complement agricultural production. One substantial source of NTFPs are palm species. Palms are sources of food, building materials, cloth, ornaments, medicines, and are also used for cultural purposes. In southern Mozambique two important palms species used as NTFPs are Hyphaene coriacea and Phoenix reclinata. These two species provide an array of subsistence and commercial products. The sap, leaves and stems of these two palms are harvested by local people as sources of traditional beverages, weaving, roofing, fencing and furniture material as well as other household utensils. The effects (if any) of harvesting of these palm products on palm distribution, population structure, dynamics and viability have never been examined, and thus the sustainability of the practices and benefits flows to local livelihoods are unknow-n. Any effects harvesting effects may also be exacerbated by predicted climate change for the area. The present study aims to investigate the role of the palm species Hyphaene coriacea and Phoenix reclinata in the livelihoods of households in the Zitundo area, Matutuine district, southern Mozambique and under future climate scenarios. Specifically, this study: i) evaluates the abundance, population structure and harvesting selection of these species; ii) characterizes the ethnobotanical knowledge and use of the two species; iii) examines the local production and trade of palm wine in the area; iv) examines the contribution of palm income to livelihoods and income diversification in area; v) describes the local management practices and perceptions on palm productivity and abundance; and vi) models the current and future distribution of the these palm species in the area. To evaluate the abundance, population structure and stability of these two palm species a population census was carried out, and the size class distribution, Simpson index of dominance, permutation index and the quotient between successive size classes were calculated. I further calculated the preference ratio for specific size classes. Additionally a questionnaire survey was conducted with 179 randomly selected households from the 16 villages in the study area to characterize the ethnobotanical knowledge and use of these two species, as well as to examine the contribution of palm income to livelihoods and diversification. Standard ethnobotanical indices were used as measures of each palm species use and knowledge while principal component analysis and cluster analysis were applied to highlight the livelihood patterns and the role of diversification and of palm income in local livelihoods. Structured interviews with 37 palm tappers were additionally used to examine the local production and trade of palm wine in the area, while both the household survey and palm tappers interviews, were employed to investigate the local management practices and perceptions on palms productivity and abundance. Maxent Software was used to model the current and future under climate change distribution of the two palm species. Hyphaene coriacea was more abundant than Phoenix reclinata. Both species exhibited steep negative slopes in the regression analyses of size class distribution, indicating the presence of more individuals in shorter size classes. Although there was a dominance of shorter over taller size classes, limited recruitment was observed through low stem densities of seedlings and juveniles compared to the 1-50 cm size class The Simpson index of dominance, the permutation index, and the fluctuating quotients between the consecutive size classes showed a level of instability in both populations. Hyphaene coriacea appeared to be more resilient to tapping than Phoenix reclinata as showed by the higher rate of stem survival after tapping. Hyphaene coriacea was favored for tapping compared to Phoenix reclinata. The most preferred size class to tap for both species was between 101cm and 150 cm. Currently the distribution of Hyphaene coriacea and Phoenix reclinata was mostly confined to the eastern side of the study area. Most of the area was predicted as unsuitable for both palm species, with less than six percent predicted to be suitable or higher. The occurrence of both species appeared to be influenced mostly by water related variables, such as precipitation, and distance to rivers and distance to water bodies. The habitat suitability for Hyphaene coriacea was predicted to increase under future climate conditions scenarios, while little variation was predicted for Phoenix reclinata distribution. The knowledge about the uses of these two palm species was widespread in the area, although only 32% of respondents were engaged in palm exploitation. Thirteen palm products were exploited, with palm wine production from the sap of both palms being the dominant activity, followed by broom production from Phoenix reclinata stems and basket production from Hyphaene coriacea leaves. The cultural importance of these species included the production of anklets and skirts used during traditional dances and the use of palm wine in the traditional ritual of libation. Palm tapping was practiced year round in five of the sixteen villages in the area. Palm tapping was an important livelihood activity, contributing over 80% of tappers’ total annual income, and tappers earned up to three times more than the national minimum wage for the agricultural and forestry sector. Palm wine was also a highly commercial commodity in Zitundo area, with an average commercialization index above 60%. The income from palm wine sales showed an important role in mitigating the level of poverty in the area. Palm income accounted for over 60% reduction on poverty incidence among palm tappers. Households in Zitundo further engaged in some level of livelihood diversification. The majority of households adopted a wage-based strategy, although this strategy was among the less remunerative in terms of per capita cash income. A palm-based livelihood strategy, although adopted only by 11% of households, was one of the most remunerative strategies. Palm income played a vital role in enhancing household livelihoods and mitigating poverty in the area as shown by the lower poverty incidences among households engaged in the palm-based livelihood strategy than alternatives strategies. The village of household residency, along with household demographic and socio-economic characteristics appeared to determine the knowledge and exploitation level of palms as well as a households’ choice of livelihood strategy, level of palm wine returns, commercialization index and palm income dependency. The importance of palms in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area. Palm wine, broom and basket production have a high potential for income generation, and therefore should be included in future local development policies and poverty reduction strategies. Although palms are an open access resource in Zitundo area, the perception is that they are abundant and that tapping does not have many detrimental effects. However, this study found some negative impacts of tapping on the recruitment of both palms species. The inclusion of palm products in future development programs and poverty reduction strategies will require the design of participatory conservation and management strategies that involve all palm users groups and others stakeholders and include long-term participatory monitoring of the effect of palm use on the populations.
- Full Text:
- Date Issued: 2020
The determination of whether a Unified Communication System can be effective in supporting informal communication and collaboration in virtual teams
- Authors: Hill, Kyle
- Date: 2020
- Subjects: Telecommuting , Virtual work teams , Telecommunication systems , Computer networks
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146343 , vital:38517
- Description: The overall objective of the research is to determine whether a Unified Communication System intervention can be effective in supporting informal communication and collaboration in virtual teams. In so doing, this research is aimed at developing a current framework of critical success factors for facilitating informal collaboration and communication. As teams have evolved to the point where there is no longer a need for team members to be co-located, with a greater importance now being placed on how they collaborate, this framework will also highlight how it can support virtual teams due to the huge potential advantage they can provide to the organisation. A virtual communication and collaboration system will be selected based on the outputs of the current framework and interactions which occur through the system will be observed to provide quantitative and qualitative results. In conclusion, the research will suggest recommendations for the successful implementation of informal communication and collaboration technologies within the organisation. The research will also indicate to a limited degree, the impact of the implementation of these technologies, and the outcome for the organisation, whether positive or negative. Whilst conducting the research, it became apparent that while the UCS was capable of performing the processes and functions required, the individuals and teams engaging with the technology did not always make use of the full scope of the technology provided. Regardless, a UCS was observed to provide direct benefits to an organisation in increasing communication and collaboration in the organisation. These increases can be observed in both the physical and virtual sense. However, the converse is true for generating social capital which lead to the observation that there are a smaller number of interactions happening in the smaller teams, but these are of higher value when compared to the larger teams of this study. It is also clear that the larger a team becomes, the more the trend is to focus on adopting new technologies to make their roles more efficient. This adoption is not however translated into outputs such as social capital but is translated into stronger networks and the formation of new networks. It is also clear that most negative factors around the UCS are related to the respondent’s hardware rather than the solution itself. Cost reductions because of virtuality will also be observed and using the Developed Framework as a blue print, an organisation should be able to observe direct benefits for an organisation by being able to confirm the thesis of this research in that having a UCS intervention is effective in supporting informal communication and collaboration in virtual teams.
- Full Text:
- Date Issued: 2020
- Authors: Hill, Kyle
- Date: 2020
- Subjects: Telecommuting , Virtual work teams , Telecommunication systems , Computer networks
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146343 , vital:38517
- Description: The overall objective of the research is to determine whether a Unified Communication System intervention can be effective in supporting informal communication and collaboration in virtual teams. In so doing, this research is aimed at developing a current framework of critical success factors for facilitating informal collaboration and communication. As teams have evolved to the point where there is no longer a need for team members to be co-located, with a greater importance now being placed on how they collaborate, this framework will also highlight how it can support virtual teams due to the huge potential advantage they can provide to the organisation. A virtual communication and collaboration system will be selected based on the outputs of the current framework and interactions which occur through the system will be observed to provide quantitative and qualitative results. In conclusion, the research will suggest recommendations for the successful implementation of informal communication and collaboration technologies within the organisation. The research will also indicate to a limited degree, the impact of the implementation of these technologies, and the outcome for the organisation, whether positive or negative. Whilst conducting the research, it became apparent that while the UCS was capable of performing the processes and functions required, the individuals and teams engaging with the technology did not always make use of the full scope of the technology provided. Regardless, a UCS was observed to provide direct benefits to an organisation in increasing communication and collaboration in the organisation. These increases can be observed in both the physical and virtual sense. However, the converse is true for generating social capital which lead to the observation that there are a smaller number of interactions happening in the smaller teams, but these are of higher value when compared to the larger teams of this study. It is also clear that the larger a team becomes, the more the trend is to focus on adopting new technologies to make their roles more efficient. This adoption is not however translated into outputs such as social capital but is translated into stronger networks and the formation of new networks. It is also clear that most negative factors around the UCS are related to the respondent’s hardware rather than the solution itself. Cost reductions because of virtuality will also be observed and using the Developed Framework as a blue print, an organisation should be able to observe direct benefits for an organisation by being able to confirm the thesis of this research in that having a UCS intervention is effective in supporting informal communication and collaboration in virtual teams.
- Full Text:
- Date Issued: 2020
The effects of economic and political instability on decentralised secondary schools in Mashonaland Central Province, Zimbabwe: a case study
- Authors: Katsinde, Tapfuiwa James
- Date: 2020
- Subjects: Education, Secondary -- Political aspects -- Zimbabwe , Political violence -- Zimbabwe , Zimbabwe -- Economic conitions -- 1980- , Zimbabwe -- Politics and government -- 1980-
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/165610 , vital:41263
- Description: The purpose of the study was to analyse the effects of economic and political instability on decentralised secondary schools in Mashonaland Central Province, Zimbabwe between 2000 and 2017. Previous studies in Zimbabwe and elsewhere have shown that schools were negatively affected by economic and political instability. This study adds to this literature by using habitus as a conceptual framework. This was a qualitative study which made use of a multi-case research design. Data was collected using focus group discussions, interviews and document analysis. Eight research sites in the form of secondary schools in four districts were used. Data analysis was done using theoretical prepositions guided by research objectives and research questions. Data presentations was characterised by quotes of participants. Trustworthiness based on dependability, credibility, transferability and conformability formed the basis of quality assurance measures. The study revealed that economic and political instability had similar negative results in the field of secondary schools in the province. Economic instability negatively affected school activities which included teaching and learning, administration and development work. In addition economic instability affected individual secondary school actors psychologically. Economic instability affected relations among the secondary school actors by aggravating already existing contestations amongst actors. Similarly, political instability affected secondary school activities such as teaching and learning, school administration, development, donations and social benefits. Secondary school actors were individually affected psychologically and through physical abuse and the way they responded to political instability. The study has shown that decentralised secondary schools found it difficult to solve the problems introduced by economic and political instability especially when the instabilities occurred within the difficulties of the broader Zimbabwean context. It is therefore recommended that decentralised secondary schools should be assisted financially and with resources to withstand economic challenges. There is a need to protect secondary schools from political activities and activists as these have devastating effects on education if allowed to have a free reign. Further similar research is recommended for other provinces in the country.
- Full Text:
- Date Issued: 2020
- Authors: Katsinde, Tapfuiwa James
- Date: 2020
- Subjects: Education, Secondary -- Political aspects -- Zimbabwe , Political violence -- Zimbabwe , Zimbabwe -- Economic conitions -- 1980- , Zimbabwe -- Politics and government -- 1980-
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/165610 , vital:41263
- Description: The purpose of the study was to analyse the effects of economic and political instability on decentralised secondary schools in Mashonaland Central Province, Zimbabwe between 2000 and 2017. Previous studies in Zimbabwe and elsewhere have shown that schools were negatively affected by economic and political instability. This study adds to this literature by using habitus as a conceptual framework. This was a qualitative study which made use of a multi-case research design. Data was collected using focus group discussions, interviews and document analysis. Eight research sites in the form of secondary schools in four districts were used. Data analysis was done using theoretical prepositions guided by research objectives and research questions. Data presentations was characterised by quotes of participants. Trustworthiness based on dependability, credibility, transferability and conformability formed the basis of quality assurance measures. The study revealed that economic and political instability had similar negative results in the field of secondary schools in the province. Economic instability negatively affected school activities which included teaching and learning, administration and development work. In addition economic instability affected individual secondary school actors psychologically. Economic instability affected relations among the secondary school actors by aggravating already existing contestations amongst actors. Similarly, political instability affected secondary school activities such as teaching and learning, school administration, development, donations and social benefits. Secondary school actors were individually affected psychologically and through physical abuse and the way they responded to political instability. The study has shown that decentralised secondary schools found it difficult to solve the problems introduced by economic and political instability especially when the instabilities occurred within the difficulties of the broader Zimbabwean context. It is therefore recommended that decentralised secondary schools should be assisted financially and with resources to withstand economic challenges. There is a need to protect secondary schools from political activities and activists as these have devastating effects on education if allowed to have a free reign. Further similar research is recommended for other provinces in the country.
- Full Text:
- Date Issued: 2020
The forensic mental health profile of women offenders in the Eastern Cape, South Africa
- Authors: Nagdee, Mohammed
- Date: 2020
- Subjects: Female offenders -- Mental health , Female offenders -- South Africa -- Psychology , Female offenders -- South Africa -- Mental health , People with mental disabilities and crime , Women murderers -- South Africa , Forensic psychology -- South Africa , Fort England Psychiatric Hospital
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167109 , vital:41438
- Description: Introduction There is a dearth of research on mental health issues in women offenders in South Africa, especially regarding their socio-demographic backgrounds, offence characteristics, and forensic mental health profiles. Objectives This study examined the psychosocial and forensic mental health profile of women offenders referred by eastern Cape courts for forensic evaluation. A range of socio-demographic, criminological, clinical and forensic mental health variables were systematically explored. Methods A bi-phasic, mixed methods study design was adopted. The clinical and forensic records of all women referred for forensic evaluation to Fort England forensic psychiatric hospital in the Eastern Cape, South Africa were retrospectively reviewed, comprising 173 individual cases in the study period of 1993-2017. Inferential statistical analyses (chi-squared and multivariate logistic regression) were applied to explore relationships between variables and offending outcomes of nterest. Detailed semi-structured interviews were subsequently conducted with a sub-sample of 8 women with mental disorder and violent offending ackgrounds. Interview transcripts thematically analysed. Results Most women came from impoverished and disadvantaged backgrounds. Whilst the majority were first offenders, a high proportion had violent index offences, with murder, attempted murder and assault with intent to do grievous bodily harm accounting for over half of cases. The majority of victims of violence were well known to the perpetrator, especially as biological children, intimate male partners or close family members. Biological children in their first year of life were particularly vulnerable to being victims of homicidal violence. Disproportionately high rates of pre-offence mental illness, alcohol misuse, HIV infection and prior abuse of the offender (especially by intimate male partners) were present. High rates of severe mental disorders (especially psychiatric comorbidity and psychotic-spectrum disorders), and relatively low rates of personality disorders and substance disorders were diagnosed. The majority of women were declared to lack trial competence and criminal capacity, respectively, following forensic evaluation. Women who had backgrounds of prior abuse themselves had over three mes the odds of subsequent violent offending in general, and almost six times the odds of homicidal offending in particular. Homicidal offences were significantly more commonly committed by women with no prior psychiatric history and no psychiatric comorbidity. Women who committed homicide had over eleven times of killing children as opposed to adults. Women over the age of 30 years, and those without psychiatric comorbidity, were significantly less likely to have killed children. Thematic analysis of interviews emphasized the important roles played by gender, self-image, and mental health in violent offending pathways. Conclusions A complex array of socio-demographic, criminological, clinical and forensic variables interact in women offenders of the Eastern Cape referred by courts for forensic evaluation. Exploration of these factors improves understanding of the broader psychosocial context of female offending, and of the personal experiences of the women themselves. This in turn provides an enhanced gender-focus to guide the progressive changes required in policy, legislative, clinical and research endeavours in this field.
- Full Text:
- Date Issued: 2020
- Authors: Nagdee, Mohammed
- Date: 2020
- Subjects: Female offenders -- Mental health , Female offenders -- South Africa -- Psychology , Female offenders -- South Africa -- Mental health , People with mental disabilities and crime , Women murderers -- South Africa , Forensic psychology -- South Africa , Fort England Psychiatric Hospital
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167109 , vital:41438
- Description: Introduction There is a dearth of research on mental health issues in women offenders in South Africa, especially regarding their socio-demographic backgrounds, offence characteristics, and forensic mental health profiles. Objectives This study examined the psychosocial and forensic mental health profile of women offenders referred by eastern Cape courts for forensic evaluation. A range of socio-demographic, criminological, clinical and forensic mental health variables were systematically explored. Methods A bi-phasic, mixed methods study design was adopted. The clinical and forensic records of all women referred for forensic evaluation to Fort England forensic psychiatric hospital in the Eastern Cape, South Africa were retrospectively reviewed, comprising 173 individual cases in the study period of 1993-2017. Inferential statistical analyses (chi-squared and multivariate logistic regression) were applied to explore relationships between variables and offending outcomes of nterest. Detailed semi-structured interviews were subsequently conducted with a sub-sample of 8 women with mental disorder and violent offending ackgrounds. Interview transcripts thematically analysed. Results Most women came from impoverished and disadvantaged backgrounds. Whilst the majority were first offenders, a high proportion had violent index offences, with murder, attempted murder and assault with intent to do grievous bodily harm accounting for over half of cases. The majority of victims of violence were well known to the perpetrator, especially as biological children, intimate male partners or close family members. Biological children in their first year of life were particularly vulnerable to being victims of homicidal violence. Disproportionately high rates of pre-offence mental illness, alcohol misuse, HIV infection and prior abuse of the offender (especially by intimate male partners) were present. High rates of severe mental disorders (especially psychiatric comorbidity and psychotic-spectrum disorders), and relatively low rates of personality disorders and substance disorders were diagnosed. The majority of women were declared to lack trial competence and criminal capacity, respectively, following forensic evaluation. Women who had backgrounds of prior abuse themselves had over three mes the odds of subsequent violent offending in general, and almost six times the odds of homicidal offending in particular. Homicidal offences were significantly more commonly committed by women with no prior psychiatric history and no psychiatric comorbidity. Women who committed homicide had over eleven times of killing children as opposed to adults. Women over the age of 30 years, and those without psychiatric comorbidity, were significantly less likely to have killed children. Thematic analysis of interviews emphasized the important roles played by gender, self-image, and mental health in violent offending pathways. Conclusions A complex array of socio-demographic, criminological, clinical and forensic variables interact in women offenders of the Eastern Cape referred by courts for forensic evaluation. Exploration of these factors improves understanding of the broader psychosocial context of female offending, and of the personal experiences of the women themselves. This in turn provides an enhanced gender-focus to guide the progressive changes required in policy, legislative, clinical and research endeavours in this field.
- Full Text:
- Date Issued: 2020
The incidence of musculoskeletal disorders and stakeholder perceptions of work challenges in South-Eastern Nigerian quarry mining industry
- Authors: Egwuonwu, Victor Afamerfuna
- Date: 2020
- Subjects: Quarries and quarrying -- Health aspects -- Nigeria , Musculoskeletal system -- Diseases -- Nigeria , Miners -- Health and hygiene -- Nigeria
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/141263 , vital:37957
- Description: Musculoskeletal disorders (MSDs) are very common among industrial labourers, leading to sick leave absence, disability and low productivity at work. MSDs have multifactorial causes, thereby making it difficult to pinpoint the extent of the contributions of the various risks regarding the mechanism of its pathophysiology. Previously, attempts were made to study regional pain symptoms in varying occupational groups, disregarding the particularities of the different workplace situations. It is important to highlight, that quantifying physical exposure factors that contribute to MSDs occurrence using quantitative approach alone could be inadequate. It is therefore imperative to incorporate qualitative approach to unmask accompanying psychosocial stressors, which are mostly explanatory variables. The study investigated the following: 12-month retrospective prevalence of MSDs, prospective incidence, risk factors and pattern of MSDs in a 6-month follow-up survey of selected quarry mineworkers, who reported MSDs complaints at the mine clinic. The study also determined the level of psychosocial stress associated with working in the mine by understanding stakeholders’ perception of work challenges, and how it influenced recurrence of MSDs. The study utilised a mixed method design with two phases: phase 1 was an initial baseline retrospective prevalence and a prospective cohort-control incidence survey. The Cultural and Psychosocial Influence on Disability (CUPID) questionnaire was translated into an Igbo-language version, cross-culturally adapted and utilized. The instrument was administered via oral interview and sought information on the following: demographic characteristics; pain in different anatomical sites and associated disability for tasks of daily living; as well as information on any change of job and reason during the study period, recent pain in different anatomical sites and associated disability for tasks of daily living; distress from common somatic symptoms; mental health status, sickness absence in the past 5-months for musculoskeletal pain. Phase 2 was a qualitative focus group discussion that engaged mine stakeholders on their perceptions of work challenges. Descriptive statistics of mean and standard deviation was utilised to analyse sociodemographic characteristics of participants. MSD incidence rates were estimated and the patterns of MSD incidence at different anatomical sites were also determined. The Cox proportional regression analyses were utilised to compare hazard ratios of MSD risks between the exposed cohorts and unexposed cohorts in the phase one incidence survey, alpha level was set at 0.05. Transcription, thematic and content analyses with the aid of Nvivo version 11 for windows was used to interpret stakeholders’ perception of work challenges. The incidence of MSD was 6.2 per 1000, with shoulder pain being the most reported complaint (40% prevalence). This was followed by back pain with the distribution of back pain presented as follows: upper back (20.37%), lower back (45.50%) and both (34.13%). All participants reported previous medical history of back, shoulder and neck pain. The relative risk ratio of mineworkers to MSDs was 4.57, which implies that the mineworkers were approximately 5 times more at risk of developing MSDs compared to the recruited unexposed cohorts. Meanwhile, wrist pain (43.58%) was the highest MSD complaints which lead miners to be absent from work, followed by knee and back with 35.42% and 21% respectively. Physical job risks, such as III working underground and squatting or kneeling at work were all significantly associated with MSDs recurrence in all six body parts (HR: 1.12-1.92, 95%CI). Similarly, time pressure to complete task, low decision latitude, poor job satisfaction, somatisation and mental disorder, job insecurity, poor incentive system (HR: 1.01-1.75, 95%CI) were perceived by stakeholders’ and participants alike in the study to be significantly associated with MSDs incidence. Quarrymen are exposed to high MSD risks associated with elevated psychosocial stress from their difficult work situations. The South Eastern Nigerian mine stakeholders believed that the high incidence of MSDs may have a substantial impact on health and productivity in the near future. Necessitating a clear need for the promotion of stakeholder’s engagement concerning safe work policy implementation initiatives in the sector.
- Full Text:
- Date Issued: 2020
- Authors: Egwuonwu, Victor Afamerfuna
- Date: 2020
- Subjects: Quarries and quarrying -- Health aspects -- Nigeria , Musculoskeletal system -- Diseases -- Nigeria , Miners -- Health and hygiene -- Nigeria
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/141263 , vital:37957
- Description: Musculoskeletal disorders (MSDs) are very common among industrial labourers, leading to sick leave absence, disability and low productivity at work. MSDs have multifactorial causes, thereby making it difficult to pinpoint the extent of the contributions of the various risks regarding the mechanism of its pathophysiology. Previously, attempts were made to study regional pain symptoms in varying occupational groups, disregarding the particularities of the different workplace situations. It is important to highlight, that quantifying physical exposure factors that contribute to MSDs occurrence using quantitative approach alone could be inadequate. It is therefore imperative to incorporate qualitative approach to unmask accompanying psychosocial stressors, which are mostly explanatory variables. The study investigated the following: 12-month retrospective prevalence of MSDs, prospective incidence, risk factors and pattern of MSDs in a 6-month follow-up survey of selected quarry mineworkers, who reported MSDs complaints at the mine clinic. The study also determined the level of psychosocial stress associated with working in the mine by understanding stakeholders’ perception of work challenges, and how it influenced recurrence of MSDs. The study utilised a mixed method design with two phases: phase 1 was an initial baseline retrospective prevalence and a prospective cohort-control incidence survey. The Cultural and Psychosocial Influence on Disability (CUPID) questionnaire was translated into an Igbo-language version, cross-culturally adapted and utilized. The instrument was administered via oral interview and sought information on the following: demographic characteristics; pain in different anatomical sites and associated disability for tasks of daily living; as well as information on any change of job and reason during the study period, recent pain in different anatomical sites and associated disability for tasks of daily living; distress from common somatic symptoms; mental health status, sickness absence in the past 5-months for musculoskeletal pain. Phase 2 was a qualitative focus group discussion that engaged mine stakeholders on their perceptions of work challenges. Descriptive statistics of mean and standard deviation was utilised to analyse sociodemographic characteristics of participants. MSD incidence rates were estimated and the patterns of MSD incidence at different anatomical sites were also determined. The Cox proportional regression analyses were utilised to compare hazard ratios of MSD risks between the exposed cohorts and unexposed cohorts in the phase one incidence survey, alpha level was set at 0.05. Transcription, thematic and content analyses with the aid of Nvivo version 11 for windows was used to interpret stakeholders’ perception of work challenges. The incidence of MSD was 6.2 per 1000, with shoulder pain being the most reported complaint (40% prevalence). This was followed by back pain with the distribution of back pain presented as follows: upper back (20.37%), lower back (45.50%) and both (34.13%). All participants reported previous medical history of back, shoulder and neck pain. The relative risk ratio of mineworkers to MSDs was 4.57, which implies that the mineworkers were approximately 5 times more at risk of developing MSDs compared to the recruited unexposed cohorts. Meanwhile, wrist pain (43.58%) was the highest MSD complaints which lead miners to be absent from work, followed by knee and back with 35.42% and 21% respectively. Physical job risks, such as III working underground and squatting or kneeling at work were all significantly associated with MSDs recurrence in all six body parts (HR: 1.12-1.92, 95%CI). Similarly, time pressure to complete task, low decision latitude, poor job satisfaction, somatisation and mental disorder, job insecurity, poor incentive system (HR: 1.01-1.75, 95%CI) were perceived by stakeholders’ and participants alike in the study to be significantly associated with MSDs incidence. Quarrymen are exposed to high MSD risks associated with elevated psychosocial stress from their difficult work situations. The South Eastern Nigerian mine stakeholders believed that the high incidence of MSDs may have a substantial impact on health and productivity in the near future. Necessitating a clear need for the promotion of stakeholder’s engagement concerning safe work policy implementation initiatives in the sector.
- Full Text:
- Date Issued: 2020
The Integration of Personally-owned Information and Communication Technologies (PICTs) for Teaching and Learning in Resource-Constrained Higher Education Environments – The Case of a Nigerian University
- Authors: Lewis, Oláñrewájú Olúrotimi
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163582 , vital:41050 , doi:10.21504/10962/163582
- Description: Thesis (PhD)--Rhodes University, Faculty of Commerce, Information Systems, 2020
- Full Text:
- Date Issued: 2020
- Authors: Lewis, Oláñrewájú Olúrotimi
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163582 , vital:41050 , doi:10.21504/10962/163582
- Description: Thesis (PhD)--Rhodes University, Faculty of Commerce, Information Systems, 2020
- Full Text:
- Date Issued: 2020
The international community’s implementation of the Responsibility to Protect (R2P) Principle: a Comparative Study of Sudan and Libya
- Authors: Nizeimana, John Bosco
- Date: 2020
- Subjects: Responsibility to protect (International law) , Humanitarian intervention -- Libya , Libya -- Foreign relations -- 1969- , Libya -- Politics and government -- 1969- , Humanitarian intervention -- Sudan , Sudan -- Foreign relations , Sudan -- Politics and government -- 1985-
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162631 , vital:40962
- Description: In the history of international relations, the adoption of the R2P principle in 2005 was widely understood to be a break-through in the international community’s efforts to respond to massive human rights violations and atrocities. Despite this, the international community’s implementation of the R2P has been widely contested, including in relation to its application in Sudan and Libya. There is agreement in the literature that, in both cases, the implementation of the R2P failed to achieve its intended purpose of protecting civilian populations. This thesis addresses the question of why the R2P failed in Sudan and Libya. Most explanations concerning the failure of the R2P in Sudan and Libya tend to focus on the politics of big power countries. The study argues that the failure to implement the R2P is related to the interactions between regional organisations and the international community (global organisations like UN) in attempting to solve large-scale human rights violent conflict. The study is firmly embedded in scholarly debates about humanitarian intervention so as to demonstrate the fact that this study is part of efforts to advance knowledge of scholarly debates on humanitarian intervention in this contemporary world order. The study combines a case study approach and qualitative research approach to achieve a nuanced understanding of the reason why the R2P failed in Sudan and Libya. The study relied on the use of documentary reviews and in-depth interviews of experts to collect data which was analysed using critical discourse analysis. The thesis demonstrated that the implementation of the R2P was characterised by a breakdown of the relationship between regional actors like the AU and global institutions like the UN. This breakdown contributed to the failure of the R2P in Sudan and Libya. The lack of financial and operational capacity for rapid deployment, the internal divisions with the AU, and the lack of political will within the AU members states were also cited as obstacles to the realisation of the R2P efforts in Sudan. To establish in-depth knowledge the study revealed other factors related to the politics of big power countries and how they played a part in the failure of the R2P in Sudan and Libya. Among these factors include implementation inconsistencies, the ICC factor, the absence of UNSC consensus in the response over Darfur and Libya, and the veto power factor and its implications in the efforts of the international community in both cases. This study also showed that the implementation of the R2P may not work effectively if left only to international actors to implement. Regional and sub-regional actors are important stakeholders of the R2P, and their interactions with the international community in actualising the implmementation of the R2P on the ground are essential. The manner in which the R2P was applied in Sudan and Libya is an indication its implementation requires improved interaction between regional actors and the international community at all level of collaboration including at global, regional and sub-regional level. This can build a strong foundation to drive the effective implementation of the R2P in future interventions. The findings of this thesis will significantly improve the available literature on the reason why the R2P failed in Sudan and Libya, particularly by paying much attention to the role of regional and sub-regional actors.
- Full Text:
- Date Issued: 2020
- Authors: Nizeimana, John Bosco
- Date: 2020
- Subjects: Responsibility to protect (International law) , Humanitarian intervention -- Libya , Libya -- Foreign relations -- 1969- , Libya -- Politics and government -- 1969- , Humanitarian intervention -- Sudan , Sudan -- Foreign relations , Sudan -- Politics and government -- 1985-
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162631 , vital:40962
- Description: In the history of international relations, the adoption of the R2P principle in 2005 was widely understood to be a break-through in the international community’s efforts to respond to massive human rights violations and atrocities. Despite this, the international community’s implementation of the R2P has been widely contested, including in relation to its application in Sudan and Libya. There is agreement in the literature that, in both cases, the implementation of the R2P failed to achieve its intended purpose of protecting civilian populations. This thesis addresses the question of why the R2P failed in Sudan and Libya. Most explanations concerning the failure of the R2P in Sudan and Libya tend to focus on the politics of big power countries. The study argues that the failure to implement the R2P is related to the interactions between regional organisations and the international community (global organisations like UN) in attempting to solve large-scale human rights violent conflict. The study is firmly embedded in scholarly debates about humanitarian intervention so as to demonstrate the fact that this study is part of efforts to advance knowledge of scholarly debates on humanitarian intervention in this contemporary world order. The study combines a case study approach and qualitative research approach to achieve a nuanced understanding of the reason why the R2P failed in Sudan and Libya. The study relied on the use of documentary reviews and in-depth interviews of experts to collect data which was analysed using critical discourse analysis. The thesis demonstrated that the implementation of the R2P was characterised by a breakdown of the relationship between regional actors like the AU and global institutions like the UN. This breakdown contributed to the failure of the R2P in Sudan and Libya. The lack of financial and operational capacity for rapid deployment, the internal divisions with the AU, and the lack of political will within the AU members states were also cited as obstacles to the realisation of the R2P efforts in Sudan. To establish in-depth knowledge the study revealed other factors related to the politics of big power countries and how they played a part in the failure of the R2P in Sudan and Libya. Among these factors include implementation inconsistencies, the ICC factor, the absence of UNSC consensus in the response over Darfur and Libya, and the veto power factor and its implications in the efforts of the international community in both cases. This study also showed that the implementation of the R2P may not work effectively if left only to international actors to implement. Regional and sub-regional actors are important stakeholders of the R2P, and their interactions with the international community in actualising the implmementation of the R2P on the ground are essential. The manner in which the R2P was applied in Sudan and Libya is an indication its implementation requires improved interaction between regional actors and the international community at all level of collaboration including at global, regional and sub-regional level. This can build a strong foundation to drive the effective implementation of the R2P in future interventions. The findings of this thesis will significantly improve the available literature on the reason why the R2P failed in Sudan and Libya, particularly by paying much attention to the role of regional and sub-regional actors.
- Full Text:
- Date Issued: 2020
The lived experiences of women with human immunodeficiency virus (HIV) in Malawi: an interpretative phenomenological analysis (IPA)
- Authors: Nkhalamba, Mathero Michelle
- Date: 2020
- Subjects: HIV-positive women -- Malawi , HIV infections -- Sex factors -- Malawi , HIV infections -- Social aspects -- Malawi , HIV-positive women -- Malawi -- Social conditions , HIV-positive women -- Malawi -- Economic conditions , Poverty -- Malawi , Antiretroviral agents -- Malawi , Phenomenological psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145291 , vital:38425
- Description: Research on African women and HIV, particularly research that investigates their experiences of living with the virus, has been relatively peripheral. As a response to the apparent knowledge and research gaps, this project is a qualitative study involving women living with human immunodeficiency virus (WLHIV) and attending an anti-retroviral treatment (ART) clinic at Zomba Central Hospital in Southern Malawi. The study utilised an interpretative phenomenological analysis (IPA) approach, which informed all aspects of the data-collection and data-analysis processes. Using purposive sampling, 12 women were recruited and interviewed on three occasions over a period of six months. The interviews were conducted in Chichewa and audio recorded and later transcribed into English. Fourteen superordinate themes emerged from the analysis representing the women’s prominent life experiences, how they received their diagnosis, and how they contained the trauma of their diagnosis. The analysis also developed themes regarding how they coped with the challenges of living with the human immunodeficiency virus (HIV) and made sense of their experiences. The results showed that the women struggled with multiple challenges experienced through their various identities as WLHIV. The findings also pointed to interlocking disadvantages that put the women at risk of infection, and which were present from childhood. This has implications for more structural and multidisciplinary interventions for WLHIV.
- Full Text:
- Date Issued: 2020
- Authors: Nkhalamba, Mathero Michelle
- Date: 2020
- Subjects: HIV-positive women -- Malawi , HIV infections -- Sex factors -- Malawi , HIV infections -- Social aspects -- Malawi , HIV-positive women -- Malawi -- Social conditions , HIV-positive women -- Malawi -- Economic conditions , Poverty -- Malawi , Antiretroviral agents -- Malawi , Phenomenological psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145291 , vital:38425
- Description: Research on African women and HIV, particularly research that investigates their experiences of living with the virus, has been relatively peripheral. As a response to the apparent knowledge and research gaps, this project is a qualitative study involving women living with human immunodeficiency virus (WLHIV) and attending an anti-retroviral treatment (ART) clinic at Zomba Central Hospital in Southern Malawi. The study utilised an interpretative phenomenological analysis (IPA) approach, which informed all aspects of the data-collection and data-analysis processes. Using purposive sampling, 12 women were recruited and interviewed on three occasions over a period of six months. The interviews were conducted in Chichewa and audio recorded and later transcribed into English. Fourteen superordinate themes emerged from the analysis representing the women’s prominent life experiences, how they received their diagnosis, and how they contained the trauma of their diagnosis. The analysis also developed themes regarding how they coped with the challenges of living with the human immunodeficiency virus (HIV) and made sense of their experiences. The results showed that the women struggled with multiple challenges experienced through their various identities as WLHIV. The findings also pointed to interlocking disadvantages that put the women at risk of infection, and which were present from childhood. This has implications for more structural and multidisciplinary interventions for WLHIV.
- Full Text:
- Date Issued: 2020
The management of lions (Panthera Leo) in small, fenced wildlife reserves
- Authors: McEvoy, Orla
- Date: 2020
- Subjects: Lion -- Behavior -- South Africa , Spatial behavior in animals -- South Africa , Animal populations -- South Africa , Game reserves -- South Africa -- Management
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143471 , vital:38249
- Description: Reintroduced lion (Panthera leo) populations pose several ecological and management challenges in small (< 1,000 km2), fenced wildlife reserves. Changes in the natural socialecological conditions of reintroduced lion populations may lead to rapid population growth and a breakdown of natural predator-prey relationships. Reduced competition with other lions also likely reduces the potential for reintroduced lions to naturally form groups. My study used a combination of questionnaire surveys with tourists, existing lion demographic data from 16 wildlife reserves across South Africa and a controlled lion social experiment to address these ecological and management issues. Tourism was the primary reason for lion reintroductions. Tourists scored lions highly in terms of preference for viewing on safari, in particular, lions in larger, natural groups and adult males. Viewing lions also enhanced a tourists’ overall safari experience. The breakdown of natural social behaviour may likely therefore reduce tourist satisfaction related to lions. The number of resident prides and male coalitions in a reserve affected lion vital rates. Lion population growth rate was highest in reserves that contained a single resident pride, and the presence of unknown adult males significantly reduced cub survival and lioness birth intervals. The ratio of male cubs born also increased in reserves with a higher density of unknown adult males. Fertility control measures (deslorelin implants and unilateral hysterectomy) were effective at limiting lion population growth. Deslorelin treatment increased the age of first reproduction or the birth interval and decreased the subsequent litter size of treated lionesses to closer reflect natural vital rates in larger (> 10, 000 km2) systems. However, there was variability in infertility response between lionesses including adverse reactions in a small proportion of treated individuals. The number of resident prides and male coalitions in a reserve affected lion social behaviour. Lionesses formed larger groups in reserves with a higher density of unknown adult female neighbours, likely driven by territory defence. Lion prides with resident cubs were generally more fragmented, likely in response to reduced competition from unknown adult males. However, in areas with a high density of unknown adult female neighbours, prides with cubs formed larger groups likely in response to heightened territory defence. Therefore, with smaller foraging group sizes, predation rate was increased in reserves with reduced competition from unknown lions. My study supports a metapopulation approach for the management of lions in small, fenced reserves, and the standardisation of lion management procedures and database management. Endorsed by the Biodiversity Management Plan for lions in South Africa, this will enhance the long-term conservation potential of isolated populations.
- Full Text:
- Date Issued: 2020
- Authors: McEvoy, Orla
- Date: 2020
- Subjects: Lion -- Behavior -- South Africa , Spatial behavior in animals -- South Africa , Animal populations -- South Africa , Game reserves -- South Africa -- Management
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143471 , vital:38249
- Description: Reintroduced lion (Panthera leo) populations pose several ecological and management challenges in small (< 1,000 km2), fenced wildlife reserves. Changes in the natural socialecological conditions of reintroduced lion populations may lead to rapid population growth and a breakdown of natural predator-prey relationships. Reduced competition with other lions also likely reduces the potential for reintroduced lions to naturally form groups. My study used a combination of questionnaire surveys with tourists, existing lion demographic data from 16 wildlife reserves across South Africa and a controlled lion social experiment to address these ecological and management issues. Tourism was the primary reason for lion reintroductions. Tourists scored lions highly in terms of preference for viewing on safari, in particular, lions in larger, natural groups and adult males. Viewing lions also enhanced a tourists’ overall safari experience. The breakdown of natural social behaviour may likely therefore reduce tourist satisfaction related to lions. The number of resident prides and male coalitions in a reserve affected lion vital rates. Lion population growth rate was highest in reserves that contained a single resident pride, and the presence of unknown adult males significantly reduced cub survival and lioness birth intervals. The ratio of male cubs born also increased in reserves with a higher density of unknown adult males. Fertility control measures (deslorelin implants and unilateral hysterectomy) were effective at limiting lion population growth. Deslorelin treatment increased the age of first reproduction or the birth interval and decreased the subsequent litter size of treated lionesses to closer reflect natural vital rates in larger (> 10, 000 km2) systems. However, there was variability in infertility response between lionesses including adverse reactions in a small proportion of treated individuals. The number of resident prides and male coalitions in a reserve affected lion social behaviour. Lionesses formed larger groups in reserves with a higher density of unknown adult female neighbours, likely driven by territory defence. Lion prides with resident cubs were generally more fragmented, likely in response to reduced competition from unknown adult males. However, in areas with a high density of unknown adult female neighbours, prides with cubs formed larger groups likely in response to heightened territory defence. Therefore, with smaller foraging group sizes, predation rate was increased in reserves with reduced competition from unknown lions. My study supports a metapopulation approach for the management of lions in small, fenced reserves, and the standardisation of lion management procedures and database management. Endorsed by the Biodiversity Management Plan for lions in South Africa, this will enhance the long-term conservation potential of isolated populations.
- Full Text:
- Date Issued: 2020
The precarious ‘good mother’ position: a psychosocial reading of maternal subjectivity of working mothers in scarcely-resourced South African communities
- Authors: Kinahan-Sweeney, Siobhan
- Date: 2020
- Subjects: Motherhood -- Psychological aspects -- South Africa , Working mothers -- South Africa -- Attitudes , Working mothers -- South Africa -- Psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142464 , vital:38082
- Description: This psychosocial study investigates the maternal subjectivities of mothers returning to work after maternity leave, who are living in scarcely-resourced Cape Town communities in South Africa. Engaging with interview texts and listening to mothers’ talk, I explore how and why maternal subjectivity is constructed discursively and defensively in our talk. This thesis claims that these particular mothers predominately employ instrumental mothering discourse. The traditional subject position of the intensive mother – which is typically assumed to be the ‘good mother’ – is not a position available to these mothers due to their social circumstances and working role. Subsequently, material provision, the baby’s thriving and surviving body, finding substitute carers and maternal preoccupation are constructed as qualities of ‘good mothering’ in their talk. This ‘good mother’ position, however, is a precarious position that both these mothers and I invest in to defend against feelings towards their babies and themselves as well as to deny (maternal) ambivalence in a problematic social system. In a combined analysis drawing on discursive theory and psychoanalysis, more specifically contemporary attachment theory and intersubjectivity theory, I illustrate how both these mothers and I – as emotional, social and political subjects – co-construct maternal subjectivity. Based on the findings, recommendations for parent-infant interventions are discussed. Arguing that a purely psychoanalytic reading of investment perpetuates notions of individual blame and pathology, I advocate for a psychosocial reading that does not neglect failing social systems but rather pursues an open and reflective, yet critical, mindfulness when listening to talk.
- Full Text:
- Date Issued: 2020
- Authors: Kinahan-Sweeney, Siobhan
- Date: 2020
- Subjects: Motherhood -- Psychological aspects -- South Africa , Working mothers -- South Africa -- Attitudes , Working mothers -- South Africa -- Psychology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/142464 , vital:38082
- Description: This psychosocial study investigates the maternal subjectivities of mothers returning to work after maternity leave, who are living in scarcely-resourced Cape Town communities in South Africa. Engaging with interview texts and listening to mothers’ talk, I explore how and why maternal subjectivity is constructed discursively and defensively in our talk. This thesis claims that these particular mothers predominately employ instrumental mothering discourse. The traditional subject position of the intensive mother – which is typically assumed to be the ‘good mother’ – is not a position available to these mothers due to their social circumstances and working role. Subsequently, material provision, the baby’s thriving and surviving body, finding substitute carers and maternal preoccupation are constructed as qualities of ‘good mothering’ in their talk. This ‘good mother’ position, however, is a precarious position that both these mothers and I invest in to defend against feelings towards their babies and themselves as well as to deny (maternal) ambivalence in a problematic social system. In a combined analysis drawing on discursive theory and psychoanalysis, more specifically contemporary attachment theory and intersubjectivity theory, I illustrate how both these mothers and I – as emotional, social and political subjects – co-construct maternal subjectivity. Based on the findings, recommendations for parent-infant interventions are discussed. Arguing that a purely psychoanalytic reading of investment perpetuates notions of individual blame and pathology, I advocate for a psychosocial reading that does not neglect failing social systems but rather pursues an open and reflective, yet critical, mindfulness when listening to talk.
- Full Text:
- Date Issued: 2020
The role of microhabitats within mangroves: an invertebrate and fish larval perspective
- Authors: Vorsatz, Lyle Dennis
- Date: 2020
- Subjects: Mangrove ecology -- South Africa , Mangrove forests -- South Africa , Niche (Ecology) , Rhizophora mucronata , Acanthaceae , Rhizophoraceae , Fishes -- Larvae -- South Africa , Aquatic ecology -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167644 , vital:41499
- Description: Microhabitats provided through structural complexity are central for the diversity, productivity, connectivity and niche differentiation within and among ecosystems. Mangrove forests afford juvenile fish and invertebrates with nursery and recruitment habitats, facilitated by the fine scale configuration of their specialised root systems. Although the importance of mangroves for resident and transient juveniles is well recognised, the roles that mangrove microhabitats play for larvae is not yet comprehensively understood. This study aimed to determine how microhabitats with varying degrees of complexity influence the composition, abundance and distribution of larval communities that inhabit mangrove forests and the physiological responses of larvae to acute temperature variations in relation to ontogenetic stage and microenvironment exposure. Two relatively pristine study sites were selected to represent a warm temperate and subtropical mangrove system in the Eastern Cape and KwaZulu-Natal on the east coast of South Africa, respectively. The differences in complexity among the root systems of Rhizophora mucronata, Avicennia marina and Bruguiera gymnorhiza were assessed using 3D scanning and the computed 3D models were then analysed using four complexity metrics. Results indicated that A. marina is the most complex in terms of surface-volume ratio, R. mucronata has the most interstitial space among its roots and B. gymnorhiza and R. mucronata differ in their fractal dimensions. Larvae collected in each microhabitat at each site using light traps showed that, despite temperature and salinity homogeneity across microenvironments, spatio-temporal differences occurred in both fish and invertebrate assemblages. This trend suggests that microhabitat structural complexity exerts an influence on larval community composition by acting as a microscape of available habitat, which ensures ecological linkages within and among the mangrove forest and adjacent ecosystems. In addition, the oxygen consumption rates of mangrove-associated brachyuran larvae varied according to mangrove microhabitat, whereby larvae collected at less complex environments had the highest metabolic rates at increased temperatures. Moreover, ontogenetic shifts in physiology were prevalent as older brachyuran larvae were more eurythermal than earlier stages, suggesting that thermally stressful events will have a greater impact on recently spawned larvae. Overall, the interstitial spaces within individual root systems are the most important complexity measure, as utilisation of these mangrove microhabitats is scale-dependent, and larvae will most likely occupy spaces inaccessible to large predators. Likewise, microscale variation in the environmental conditions and ontogenetic stage of brachyuran larvae within the mangrove microscape, can amplify the physiological responses to rapid temperature variations. Results suggest that early stage larvae are the most vulnerable to mass-mortality, and if thermally stressful events increase in frequency, duration and magnitude, the larval supply for the successful recruitment into adult populations could be under threat. Through linking how mangrove microhabitat complexity influences larvae in terms of community metrics and physiology, this study paves the way for further advancement of our understanding of how microscale processes emerge into meso- and macroscale patterns and influence the stability and functioning of highly productive ecosystems.
- Full Text:
- Date Issued: 2020
- Authors: Vorsatz, Lyle Dennis
- Date: 2020
- Subjects: Mangrove ecology -- South Africa , Mangrove forests -- South Africa , Niche (Ecology) , Rhizophora mucronata , Acanthaceae , Rhizophoraceae , Fishes -- Larvae -- South Africa , Aquatic ecology -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167644 , vital:41499
- Description: Microhabitats provided through structural complexity are central for the diversity, productivity, connectivity and niche differentiation within and among ecosystems. Mangrove forests afford juvenile fish and invertebrates with nursery and recruitment habitats, facilitated by the fine scale configuration of their specialised root systems. Although the importance of mangroves for resident and transient juveniles is well recognised, the roles that mangrove microhabitats play for larvae is not yet comprehensively understood. This study aimed to determine how microhabitats with varying degrees of complexity influence the composition, abundance and distribution of larval communities that inhabit mangrove forests and the physiological responses of larvae to acute temperature variations in relation to ontogenetic stage and microenvironment exposure. Two relatively pristine study sites were selected to represent a warm temperate and subtropical mangrove system in the Eastern Cape and KwaZulu-Natal on the east coast of South Africa, respectively. The differences in complexity among the root systems of Rhizophora mucronata, Avicennia marina and Bruguiera gymnorhiza were assessed using 3D scanning and the computed 3D models were then analysed using four complexity metrics. Results indicated that A. marina is the most complex in terms of surface-volume ratio, R. mucronata has the most interstitial space among its roots and B. gymnorhiza and R. mucronata differ in their fractal dimensions. Larvae collected in each microhabitat at each site using light traps showed that, despite temperature and salinity homogeneity across microenvironments, spatio-temporal differences occurred in both fish and invertebrate assemblages. This trend suggests that microhabitat structural complexity exerts an influence on larval community composition by acting as a microscape of available habitat, which ensures ecological linkages within and among the mangrove forest and adjacent ecosystems. In addition, the oxygen consumption rates of mangrove-associated brachyuran larvae varied according to mangrove microhabitat, whereby larvae collected at less complex environments had the highest metabolic rates at increased temperatures. Moreover, ontogenetic shifts in physiology were prevalent as older brachyuran larvae were more eurythermal than earlier stages, suggesting that thermally stressful events will have a greater impact on recently spawned larvae. Overall, the interstitial spaces within individual root systems are the most important complexity measure, as utilisation of these mangrove microhabitats is scale-dependent, and larvae will most likely occupy spaces inaccessible to large predators. Likewise, microscale variation in the environmental conditions and ontogenetic stage of brachyuran larvae within the mangrove microscape, can amplify the physiological responses to rapid temperature variations. Results suggest that early stage larvae are the most vulnerable to mass-mortality, and if thermally stressful events increase in frequency, duration and magnitude, the larval supply for the successful recruitment into adult populations could be under threat. Through linking how mangrove microhabitat complexity influences larvae in terms of community metrics and physiology, this study paves the way for further advancement of our understanding of how microscale processes emerge into meso- and macroscale patterns and influence the stability and functioning of highly productive ecosystems.
- Full Text:
- Date Issued: 2020
The role of the Hop co-chaperone in the formation of Hsp90 complexes: chaperone link to glycolysis
- Authors: Maharaj, Shantal
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Maharaj, Shantal
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Thermal tolerance and the potential effects of climate change on coastal intertidal and estuarine organisms in the Kariega Estuary and adjacent intertitdal coastline, Eastern Cape, South Africa
- Authors: Van der Walt, Kerry-Ann
- Date: 2020
- Subjects: Ectotherms -- Climatic factors , Ectotherms -- Effect of temperature on , Fishes -- Climatic factors , Fishes -- Effect of temperature on , Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/148459 , vital:38741
- Description: Temperature changes due to the effects of climate change are evident on all continents and oceans. As a result, there is a growing concern over how marine ectotherms will respond to extreme or fluctuating environmental temperatures. Temperature changes have strong direct and indirect effects on individual, population, and ecosystem functioning traits. A multi-scale approach determining the thermal tolerance and performance of several marine ectotherms belonging to different coastal habitats is rarely considered in thermal physiology studies but is effective for an integrated ecosystem assessment. As such, for this thesis, I aimed to quantify and compare the thermal tolerance and performance of a range of coastal marine ectotherms (fish and macro-invertebrates) with different biogeographical distributions from estuarine, subtidal and rocky intertidal habitats to available and projected in situ temperature data. This was also undertaken to gauge the local vulnerability of each species across summer and winter in a warm-temperate region of South Africa. This was done using a multi-method physiological approach, which included the dynamic method (CTmax and CTmin), static respirometry and maximum heart rate fHmax). Results of the dynamic method on several fish and macro-invertebrate species indicated that there are differences in thermal tolerance according to taxonomy, biogeography and habitat for both summer and winter. Macro-invertebrate species generally had higher CTmax endpoints, lower CTmin endpoints, higher upper and lower breadths in tolerance, higher upper and lower thermal safety margins and higher thermal scopes than the fish species. This could be a result of the macro-invertebrate species studied being less mobile compared with fish species (which are able to move to more favourable conditions) as well as having broader geographical distributions. In addition, macro-invertebrates from the intertidal rock pool habitat (Palaemon peringueyi; Pernaperna) were more tolerant of high and low temperatures compared with the macro-invertebrates from the estuarine habitat (Clibanarius virescens; Parasesarma catenatum; Upogebia africana). Overall, macro-invertebrates, with the exception of Parechinus angulosus, investigated in this study indicated that current temperatures and projected climate change scenarios across seasons would not have a significant impact on them and that they are highly adaptable to changing temperature regimes. This sign of high tolerance was further supported by the heart rates of P. perna and P. catenatum under an acute increase in temperature (1.0 °C.h-1) which showed individuals of each species physiologically depressing their metabolism until a final Arrhenius breakpoint temperature was reached (TAB). Among the fish species investigated in this study, tropical species (Chaetodon marleyi; Kuhlia mugil) had the highest CTmax and CTmin endpoints when compared with the temperate (Diplodus capensis; Sarpa salpa), warm-water endemic (Chelon dumerili; Rhabdosargus holubi) and cool-water endemic (Chelon richardsonii) fishes. This suggests that due to their lower breadths in tolerance and thermal safety margins being small, tropical species may be less tolerant of cold temperatures and thermal variability, especially in the form of summer upwelling events which are expected to increase in intensity and frequency in this region as a result of anthropogenic climate change effects. On the other hand, however, if a temperature increase of 2.0 - 4.0 °C takes place at the end of the century as predicted by the Intergovernmental Panel on Climate Change (IPCC), it is likely that tropical species such as C. marleyi will become more common. Temperate species such as D. capensis and S. salpa were able to tolerate a wide range of temperatures (wide thermal scope) compared with the other fish species. These findings may suggest that D. capensis and S. salpa are thermally resilient and may be the least vulnerable to climate change effects and temperature variability. When evaluating the different life stages of D. capensis, however, using the dynamic method (juveniles and adults), static respirometry (juveniles) and maximum heart rate (adults), results suggested that juveniles of this temperate species will be more resilient to increases in ocean temperatures compared with the adults because they have a higher thermal tolerance (CTmax/TCRIT) and a greater metabolic scope (TOPT) at higher temperatures. For both juveniles and adults, temperatures beyond 28.0 °C (upper Tpej; Tarr) will have a significant impact on their physiology. Using a multi-scale and multi-method approach thus helped to identify which species or community may be vulnerable to the effects of climate change within shallow coastal environments in this warm-temperate climate change hotspot. Adopting this type of approach will assist policy makers in developing comprehensive climate change management frameworks for coastal ecosystems globally and around South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Van der Walt, Kerry-Ann
- Date: 2020
- Subjects: Ectotherms -- Climatic factors , Ectotherms -- Effect of temperature on , Fishes -- Climatic factors , Fishes -- Effect of temperature on , Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/148459 , vital:38741
- Description: Temperature changes due to the effects of climate change are evident on all continents and oceans. As a result, there is a growing concern over how marine ectotherms will respond to extreme or fluctuating environmental temperatures. Temperature changes have strong direct and indirect effects on individual, population, and ecosystem functioning traits. A multi-scale approach determining the thermal tolerance and performance of several marine ectotherms belonging to different coastal habitats is rarely considered in thermal physiology studies but is effective for an integrated ecosystem assessment. As such, for this thesis, I aimed to quantify and compare the thermal tolerance and performance of a range of coastal marine ectotherms (fish and macro-invertebrates) with different biogeographical distributions from estuarine, subtidal and rocky intertidal habitats to available and projected in situ temperature data. This was also undertaken to gauge the local vulnerability of each species across summer and winter in a warm-temperate region of South Africa. This was done using a multi-method physiological approach, which included the dynamic method (CTmax and CTmin), static respirometry and maximum heart rate fHmax). Results of the dynamic method on several fish and macro-invertebrate species indicated that there are differences in thermal tolerance according to taxonomy, biogeography and habitat for both summer and winter. Macro-invertebrate species generally had higher CTmax endpoints, lower CTmin endpoints, higher upper and lower breadths in tolerance, higher upper and lower thermal safety margins and higher thermal scopes than the fish species. This could be a result of the macro-invertebrate species studied being less mobile compared with fish species (which are able to move to more favourable conditions) as well as having broader geographical distributions. In addition, macro-invertebrates from the intertidal rock pool habitat (Palaemon peringueyi; Pernaperna) were more tolerant of high and low temperatures compared with the macro-invertebrates from the estuarine habitat (Clibanarius virescens; Parasesarma catenatum; Upogebia africana). Overall, macro-invertebrates, with the exception of Parechinus angulosus, investigated in this study indicated that current temperatures and projected climate change scenarios across seasons would not have a significant impact on them and that they are highly adaptable to changing temperature regimes. This sign of high tolerance was further supported by the heart rates of P. perna and P. catenatum under an acute increase in temperature (1.0 °C.h-1) which showed individuals of each species physiologically depressing their metabolism until a final Arrhenius breakpoint temperature was reached (TAB). Among the fish species investigated in this study, tropical species (Chaetodon marleyi; Kuhlia mugil) had the highest CTmax and CTmin endpoints when compared with the temperate (Diplodus capensis; Sarpa salpa), warm-water endemic (Chelon dumerili; Rhabdosargus holubi) and cool-water endemic (Chelon richardsonii) fishes. This suggests that due to their lower breadths in tolerance and thermal safety margins being small, tropical species may be less tolerant of cold temperatures and thermal variability, especially in the form of summer upwelling events which are expected to increase in intensity and frequency in this region as a result of anthropogenic climate change effects. On the other hand, however, if a temperature increase of 2.0 - 4.0 °C takes place at the end of the century as predicted by the Intergovernmental Panel on Climate Change (IPCC), it is likely that tropical species such as C. marleyi will become more common. Temperate species such as D. capensis and S. salpa were able to tolerate a wide range of temperatures (wide thermal scope) compared with the other fish species. These findings may suggest that D. capensis and S. salpa are thermally resilient and may be the least vulnerable to climate change effects and temperature variability. When evaluating the different life stages of D. capensis, however, using the dynamic method (juveniles and adults), static respirometry (juveniles) and maximum heart rate (adults), results suggested that juveniles of this temperate species will be more resilient to increases in ocean temperatures compared with the adults because they have a higher thermal tolerance (CTmax/TCRIT) and a greater metabolic scope (TOPT) at higher temperatures. For both juveniles and adults, temperatures beyond 28.0 °C (upper Tpej; Tarr) will have a significant impact on their physiology. Using a multi-scale and multi-method approach thus helped to identify which species or community may be vulnerable to the effects of climate change within shallow coastal environments in this warm-temperate climate change hotspot. Adopting this type of approach will assist policy makers in developing comprehensive climate change management frameworks for coastal ecosystems globally and around South Africa.
- Full Text:
- Date Issued: 2020
Thermoluminescence and phototransferred phermoluminescence of synthetic quartz
- Authors: Dawam, Robert Rangmou
- Date: 2020
- Subjects: Thermoluminescence , Quartz
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145849 , vital:38472
- Description: The main aim of this investigation is on thermoluminescence and phototransferred thermoluminescence of synthetic quartz. Thermoluminescence was one of the tools used in characterising the electron traps parameters. The samples of quartz annealed at various temperatures up to 900̊C and the unannealed were used. The thermoluminescence glow curve was measured at 1̊C s~ 1 following beta irradiation to 40 Gy from the samples annealed at 500̊C and the unannealed consist of main peak at 70̊C and secondary peaks at 110, 180 and 310̊C. In comparison, the thermoluminescence glow curve for the sample annealed at 900̊C have main peak at 86̊C and the secondary ones at 170 and 310̊C. The kinetic analysis was carried out only on the main peak in each case. The activation energy was found to be decreasing with increase in annealing temperatures. The samples annealed at 500̊C and the unannealed were found to be affected by thermal quenching while sample annealed at 900̊C shows an inverse quenching for irradiation dose of 40 Gy. However, when the dose was reduce to 3 Gy the effects of thermal quenching was manifested. The activation energy of thermal quenching was also found to decrease with increase in annealing temperature. Thermally assisted optically stimulated luminescence measurement was carried out using continuous wave optical stimulated luminescence (CW-OSL). The samples studied were those annealed at 500̊C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The CW-OSL is stimulated using 470 nm blue LEDs at sample temperatures between 30 and 200̊C. It is measured after preheating to either 300 and 500̊C. When the integrated OSL intensity is plotted as a function of measurement temperature, the intensity goes through a peak. The increase in OSL intensity as a function of temperature is associated to thermal assistance and the decrease to thermal quenching. The kinetic parameters were evaluated by fitting the experimental data. The values of activation energies of thermal quenching are the same within experimental uncertainties for all the experimental conditions. This shows that annealing temperature, duration of annealing and irradiation dose have a negligible influence on the recombination site of luminescence using OSL. Phototransferred thermoluminescence (PTTL) induced from annealed samples using 470 nm blue light was also investigated. The quartz were annealed at 500 _C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The glow curves of conventional TL measured at 1 _C s1 following irradiation to 200 Gy shows six peaks in each case labelled I-VI for ease of reference whereas peaks observed under PTTL are referred to as A1 onwards. Only the first three peaks were reproduced under phototransfer for the sample annealed at 900̊C for 60 minutes and 1000̊C C for 10 minutes. Interestingly, for the intermediate duration of annealing of 30 minutes, the only peak that appears under phototransfer is the A1. For quartz annealed at 900̊C for 10 minutes, the PTTL appears as long as the preheating temperature does not exceed 560̊C. All other annealing temperatures, PTTL only appears for preheating to 450 and below. This shows that the occupancy of deep electron traps at temperatures beyond 450̊C or 560̊C is low. The activation energy for peaks A1, A2 and A3 were calculated. The PTTL peaks were studied for thermal quenching and peaks A1 and A3 were found to be affected. The activation energies for thermal quenching were determined as 0.62 ± 0.04 eV and 0.65 ± 0.02 eV for peaks A1 and A3 respectively. The experimental dependence of PTTL intensity on illumination time is modelled using sets of coupled linear differential equations based on systems of donors and acceptors whose number is determined by preheating temperature.
- Full Text:
- Date Issued: 2020
- Authors: Dawam, Robert Rangmou
- Date: 2020
- Subjects: Thermoluminescence , Quartz
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145849 , vital:38472
- Description: The main aim of this investigation is on thermoluminescence and phototransferred thermoluminescence of synthetic quartz. Thermoluminescence was one of the tools used in characterising the electron traps parameters. The samples of quartz annealed at various temperatures up to 900̊C and the unannealed were used. The thermoluminescence glow curve was measured at 1̊C s~ 1 following beta irradiation to 40 Gy from the samples annealed at 500̊C and the unannealed consist of main peak at 70̊C and secondary peaks at 110, 180 and 310̊C. In comparison, the thermoluminescence glow curve for the sample annealed at 900̊C have main peak at 86̊C and the secondary ones at 170 and 310̊C. The kinetic analysis was carried out only on the main peak in each case. The activation energy was found to be decreasing with increase in annealing temperatures. The samples annealed at 500̊C and the unannealed were found to be affected by thermal quenching while sample annealed at 900̊C shows an inverse quenching for irradiation dose of 40 Gy. However, when the dose was reduce to 3 Gy the effects of thermal quenching was manifested. The activation energy of thermal quenching was also found to decrease with increase in annealing temperature. Thermally assisted optically stimulated luminescence measurement was carried out using continuous wave optical stimulated luminescence (CW-OSL). The samples studied were those annealed at 500̊C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The CW-OSL is stimulated using 470 nm blue LEDs at sample temperatures between 30 and 200̊C. It is measured after preheating to either 300 and 500̊C. When the integrated OSL intensity is plotted as a function of measurement temperature, the intensity goes through a peak. The increase in OSL intensity as a function of temperature is associated to thermal assistance and the decrease to thermal quenching. The kinetic parameters were evaluated by fitting the experimental data. The values of activation energies of thermal quenching are the same within experimental uncertainties for all the experimental conditions. This shows that annealing temperature, duration of annealing and irradiation dose have a negligible influence on the recombination site of luminescence using OSL. Phototransferred thermoluminescence (PTTL) induced from annealed samples using 470 nm blue light was also investigated. The quartz were annealed at 500 _C for 10 minutes, 900̊C for 10, 30, 60 minutes and 1000̊C for 10 minutes prior to use. The glow curves of conventional TL measured at 1 _C s1 following irradiation to 200 Gy shows six peaks in each case labelled I-VI for ease of reference whereas peaks observed under PTTL are referred to as A1 onwards. Only the first three peaks were reproduced under phototransfer for the sample annealed at 900̊C for 60 minutes and 1000̊C C for 10 minutes. Interestingly, for the intermediate duration of annealing of 30 minutes, the only peak that appears under phototransfer is the A1. For quartz annealed at 900̊C for 10 minutes, the PTTL appears as long as the preheating temperature does not exceed 560̊C. All other annealing temperatures, PTTL only appears for preheating to 450 and below. This shows that the occupancy of deep electron traps at temperatures beyond 450̊C or 560̊C is low. The activation energy for peaks A1, A2 and A3 were calculated. The PTTL peaks were studied for thermal quenching and peaks A1 and A3 were found to be affected. The activation energies for thermal quenching were determined as 0.62 ± 0.04 eV and 0.65 ± 0.02 eV for peaks A1 and A3 respectively. The experimental dependence of PTTL intensity on illumination time is modelled using sets of coupled linear differential equations based on systems of donors and acceptors whose number is determined by preheating temperature.
- Full Text:
- Date Issued: 2020
Transformative ICT education practices in rural secondary schools for developmental needs and realities: the Eastern Cape Province, South Africa
- Authors: Simuja, Clement
- Date: 2020
- Subjects: Education, Secondary -- South Africa -- Data processing , Information technology -- Study and teaching (Secondary) --South Africa , Educational technology -- Developing countries , Rural development -- Developing countries , Computer-assisted instruction -- South Africa -- Eastern Cape , Internet in education -- South Africa , Rural schools -- South Africa -- Eastern Cape , Community and school -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150631 , vital:38991
- Description: The perceived social development significance of Information and Communication Technology (ICT) has dramatically expanded the domains in which this cluster of ICTs is being discussed and acted upon. The action to promote community development in rural areas in South Africa has made its way into the introduction of ICT education in secondary schools. Since rural secondary schools form part of the framework for rural communities, they are being challenged to provide ICT education that makes a difference in learners’ lives. This requires engaging education practices that inspire learners to construct knowledge of ICT that does not only respond to examination purposes but rather, to the needs and development aspirations of the community. This research examines the experience of engaging learners and communities in socially informed ICT education in rural secondary schools. Specifically, it seeks to develop a critique of current practices involved in ICT education in rural secondary schools, and explores plausible alternatives to such practices that would make ICT education more transformative and structured towards the developmental concerns of communities. The main empirical focus for the research was five rural secondary schools in the Eastern Cape Province in South Africa. The research involved 53 participants that participated in a socially informed ICT training process. The training was designed to inspire participants to share their self-defined ICT education and ICT knowledge experiences. Critical Action Learning and Philosophical Inquiry provided the methodological framework, whilst the theoretical framework draws on Foucault’s philosophical ideas on power-knowledge relations. Through this theoretical analysis, the research examines the dynamic interplay of practices in ICT education with the values, ideals, and knowledge that form the core-life experiences of learners and rural communities. The research findings of this study indicate that current ICT education practices in rural secondary schools are endowed with ideologies that are affecting learners’ identity, social experiences, power, and ownership of the reflective meaning of using ICTs in community development. The contribution of this thesis lies in demonstrating ways that reframe ICT education transformatively, and more specifically its practices in the light of the way power, identity, ownership and social experience construct and offer learners a transformative view of self and the world. This could enable ICT education to fulfil the potential of contributing to social development in rural communities. The thesis culminates by presenting a theoretical framework that articulates the structural and authoritative components of ICT education practices – these relate to learners’ conscious understandings and represented thoughts, sensations and meanings embedded in the context, and actions and locations of using their knowledge of ICT.
- Full Text:
- Date Issued: 2020
- Authors: Simuja, Clement
- Date: 2020
- Subjects: Education, Secondary -- South Africa -- Data processing , Information technology -- Study and teaching (Secondary) --South Africa , Educational technology -- Developing countries , Rural development -- Developing countries , Computer-assisted instruction -- South Africa -- Eastern Cape , Internet in education -- South Africa , Rural schools -- South Africa -- Eastern Cape , Community and school -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/150631 , vital:38991
- Description: The perceived social development significance of Information and Communication Technology (ICT) has dramatically expanded the domains in which this cluster of ICTs is being discussed and acted upon. The action to promote community development in rural areas in South Africa has made its way into the introduction of ICT education in secondary schools. Since rural secondary schools form part of the framework for rural communities, they are being challenged to provide ICT education that makes a difference in learners’ lives. This requires engaging education practices that inspire learners to construct knowledge of ICT that does not only respond to examination purposes but rather, to the needs and development aspirations of the community. This research examines the experience of engaging learners and communities in socially informed ICT education in rural secondary schools. Specifically, it seeks to develop a critique of current practices involved in ICT education in rural secondary schools, and explores plausible alternatives to such practices that would make ICT education more transformative and structured towards the developmental concerns of communities. The main empirical focus for the research was five rural secondary schools in the Eastern Cape Province in South Africa. The research involved 53 participants that participated in a socially informed ICT training process. The training was designed to inspire participants to share their self-defined ICT education and ICT knowledge experiences. Critical Action Learning and Philosophical Inquiry provided the methodological framework, whilst the theoretical framework draws on Foucault’s philosophical ideas on power-knowledge relations. Through this theoretical analysis, the research examines the dynamic interplay of practices in ICT education with the values, ideals, and knowledge that form the core-life experiences of learners and rural communities. The research findings of this study indicate that current ICT education practices in rural secondary schools are endowed with ideologies that are affecting learners’ identity, social experiences, power, and ownership of the reflective meaning of using ICTs in community development. The contribution of this thesis lies in demonstrating ways that reframe ICT education transformatively, and more specifically its practices in the light of the way power, identity, ownership and social experience construct and offer learners a transformative view of self and the world. This could enable ICT education to fulfil the potential of contributing to social development in rural communities. The thesis culminates by presenting a theoretical framework that articulates the structural and authoritative components of ICT education practices – these relate to learners’ conscious understandings and represented thoughts, sensations and meanings embedded in the context, and actions and locations of using their knowledge of ICT.
- Full Text:
- Date Issued: 2020
Understanding a West African recreational fishery as a complex social-ecological system – a case study of the fishery for giant African threadfin Polydactylus quadrifilis (Cuvier, 1829) in the Kwanza Estuary, Angola
- Authors: Butler, Edward C
- Date: 2020
- Subjects: Cuanza River (Angola) , Fishing -- Angola , Polynemidae , Fishes -- Angola -- Ecology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146688 , vital:38548
- Description: Despite increasing global recognition of the importance of recreational fisheries, their management largely remains poor. This is because they exhibit unique human-nature relationships and are nested within complex social-ecological systems (SESs). Recreational fisheries in the developing world have large potential for socio-economic development, but are generally underappreciated, in terms of their value and their impact, and are poorly governed. This is particularly concerning as they are highly complex and often compete for resources with dependent artisanal and subsistence fisheries. Developing world recreational fishery SESs are not well understood and present an important research gap for improved governance. The general aim of this thesis was to explore the recreational fishery targeting Polydactylus quadrifilis on the Kwanza Estuary, Angola, and provide context for how managers should approach recreational fisheries in the developing world and in Africa. To do this, the recreational fishery SES was explored using a combination of methodologies including those characteristic of traditional fisheries science, and new methods involving biology, sociology, and economics. The thesis contains an introductory chapter, a chapter describing the background, study area and study species, five data chapters and a discussion chapter. Chapter 3 aimed to investigate the reproductive style of P. quadrifilis. Results identified the species as a protandrous hermaphrodite. Evidence to suggest this included degenerating testicular tissue and the presence of early developing ovarian tissues in transitional individuals. Early-stage oocytes were commonly found in the outer area of male regions and residual late-stage spermatids and spermatozoa were found in the luminal space of ovarian regions, suggesting a process of sex change from the outside inwards. Owing to the species’ reliance on large highly fecund females for reproduction, it is likely that P. quadrifilis will be sensitive to fisheries that target larger individuals, such as trophy recreational fisheries and line fisheries within other sectors. Chapter 4 aimed to investigate alternative methods for adequately describing the growth of P. quadrifilis individuals belonging to either one of two distinct hypothetical life-history pathways: pathway I (‘changers’) – initial maturation as a primary male followed by a sex change to female; pathway II (‘non-changers’) – initial maturation as a male fish with no subsequent sex change, using von Bertalanffy Growth Functions (VBGFs). Other specific objectives included determining the size- and age-at-maturity and size- and age-at-sex-change for P. quadrifilis. Otolith aging revealed rapid growth and early maturation (L50 = 399.2 mm FL, A50 = 1.50 years) and sex change occurred over a wide size (790–1125 mm FL) and age (3–8 years) range. There was strong evidence for partial protandry in P. quadrifilis with several extremely old male fish (up to 22 years) observed in the population. When compared to the conventional model produced for the entire population, there were significant differences in the models for the ‘non-changers’ (LRT, p < 0.01) and their parameters L∞ (full model = 130.8, ‘non-changers’ = 113.3, p < 0.01), k (0.32, 0.44, p < 0.01) and t0 (0.23, 0.43, p = 0.03) in the first approach and the models (LRT, p < 0.01) and their L∞ (‘changers’ = 113.7, p < 0.01) values in the second approach. This suggests that utilising conventional modelling techniques may be inappropriate for the stock assessment and management of P. quadrifilis and, potentially, other sequentially hermaphroditic fishery species. Chapter 5 aimed to assess the sensitivity of P. quadrifilis to recreational C&R within the foreign recreational fishery using a rapid assessment approach. To do this, a number of C&R variables including fight time, air exposure, hook placement, hooking injury, total time of the stress event, river depth and angling method were measured and related to two indicators of fish health and survival – the physiological stress indicators blood glucose and blood lactate concentration and reflex action mortality predictors (RAMPs). Air exposure was identified as a major contributor to motor impairment (Cumulative Link Model: p < 0.01) and fight time was an important contributor to motor impairment via its interaction with air exposure (Cumulative Link Model: p = 0.02). Handling practices appear to be particularly important for larger individuals as fish size was positively correlated with air exposure (Pearson’s r coefficient = 0.41, p < 0.01) and fight times (0.88, p < 0.01). The findings suggest that recreational C&R may result in mortalities directly, via C&R, and indirectly, via predation, and several recommendations were made for best practice. Chapter 6 aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary. Results indicated that the recreational fishery for contributed significantly to the economy of an area that would otherwise likely receive little external input ($282 054 per four-month fishing season). However, high rates of economic leakage from the study area were identified (58.7%–92.9% of locally spent revenue) and were attributed to the sourcing of lodge supplies, services and staff outside of the local area and the repatriation of profit by foreign business owners. Capacity building within the local community is likely required to develop ‘linkages’ between the local community and the recreational fishery. Greater community involvement in the fishery is suggested to incentivise the protection of recreationally important fishery species and their associated ecosystems. Chapter 7 aimed to investigate the resource user groups involved within the SES. Results illustrated that artisanal and domestic recreational anglers are well-established and are characterised by long histories of participation. The artisanal fishery was highly valued as a source of livelihoods for the local community. Artisanal fishers were eager for involvement in the recreational sector, through the chartering of their vessels, due to the attractiveness of extra earnings. Both recreational and artisanal fishers reported recent decreases in P. quadrifilis catch and anticipated further declines. Domestic recreational anglers appeared to be highly consumptive in their use of the fishery and C&R angling was uncommon. User conflict may be problematic for future management as recreational anglers perceived the artisanal gill-net fishery to be a threat towards P. quadrifilis stocks. In conclusion, the open-access nature of the fishery was identified as the most pertinent threat to its sustainability and likely needs to be addressed. Potential solutions involve offering users the opportunity to purchase access rights (e.g. day permits), thus initiating the concept that users must pay for their use of public resources. Management should aim to protect large female fish due to their increased reproductive value and worth as trophy fish. Thus, C&R angling is likely to be an important interaction between users and the resource. However, angler behaviour will need to be manipulated to promote C&R and minimise C&R-related mortalities. Solutions include angler educational drives and interventions and the implementation of competitive C&R-only angling. Foreign recreational fisheries, although touted as potential ecotourism ventures, will only succeed in improving the lives of local people if they fully integrate the community into the operation of the fishery.
- Full Text:
- Date Issued: 2020
- Authors: Butler, Edward C
- Date: 2020
- Subjects: Cuanza River (Angola) , Fishing -- Angola , Polynemidae , Fishes -- Angola -- Ecology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/146688 , vital:38548
- Description: Despite increasing global recognition of the importance of recreational fisheries, their management largely remains poor. This is because they exhibit unique human-nature relationships and are nested within complex social-ecological systems (SESs). Recreational fisheries in the developing world have large potential for socio-economic development, but are generally underappreciated, in terms of their value and their impact, and are poorly governed. This is particularly concerning as they are highly complex and often compete for resources with dependent artisanal and subsistence fisheries. Developing world recreational fishery SESs are not well understood and present an important research gap for improved governance. The general aim of this thesis was to explore the recreational fishery targeting Polydactylus quadrifilis on the Kwanza Estuary, Angola, and provide context for how managers should approach recreational fisheries in the developing world and in Africa. To do this, the recreational fishery SES was explored using a combination of methodologies including those characteristic of traditional fisheries science, and new methods involving biology, sociology, and economics. The thesis contains an introductory chapter, a chapter describing the background, study area and study species, five data chapters and a discussion chapter. Chapter 3 aimed to investigate the reproductive style of P. quadrifilis. Results identified the species as a protandrous hermaphrodite. Evidence to suggest this included degenerating testicular tissue and the presence of early developing ovarian tissues in transitional individuals. Early-stage oocytes were commonly found in the outer area of male regions and residual late-stage spermatids and spermatozoa were found in the luminal space of ovarian regions, suggesting a process of sex change from the outside inwards. Owing to the species’ reliance on large highly fecund females for reproduction, it is likely that P. quadrifilis will be sensitive to fisheries that target larger individuals, such as trophy recreational fisheries and line fisheries within other sectors. Chapter 4 aimed to investigate alternative methods for adequately describing the growth of P. quadrifilis individuals belonging to either one of two distinct hypothetical life-history pathways: pathway I (‘changers’) – initial maturation as a primary male followed by a sex change to female; pathway II (‘non-changers’) – initial maturation as a male fish with no subsequent sex change, using von Bertalanffy Growth Functions (VBGFs). Other specific objectives included determining the size- and age-at-maturity and size- and age-at-sex-change for P. quadrifilis. Otolith aging revealed rapid growth and early maturation (L50 = 399.2 mm FL, A50 = 1.50 years) and sex change occurred over a wide size (790–1125 mm FL) and age (3–8 years) range. There was strong evidence for partial protandry in P. quadrifilis with several extremely old male fish (up to 22 years) observed in the population. When compared to the conventional model produced for the entire population, there were significant differences in the models for the ‘non-changers’ (LRT, p < 0.01) and their parameters L∞ (full model = 130.8, ‘non-changers’ = 113.3, p < 0.01), k (0.32, 0.44, p < 0.01) and t0 (0.23, 0.43, p = 0.03) in the first approach and the models (LRT, p < 0.01) and their L∞ (‘changers’ = 113.7, p < 0.01) values in the second approach. This suggests that utilising conventional modelling techniques may be inappropriate for the stock assessment and management of P. quadrifilis and, potentially, other sequentially hermaphroditic fishery species. Chapter 5 aimed to assess the sensitivity of P. quadrifilis to recreational C&R within the foreign recreational fishery using a rapid assessment approach. To do this, a number of C&R variables including fight time, air exposure, hook placement, hooking injury, total time of the stress event, river depth and angling method were measured and related to two indicators of fish health and survival – the physiological stress indicators blood glucose and blood lactate concentration and reflex action mortality predictors (RAMPs). Air exposure was identified as a major contributor to motor impairment (Cumulative Link Model: p < 0.01) and fight time was an important contributor to motor impairment via its interaction with air exposure (Cumulative Link Model: p = 0.02). Handling practices appear to be particularly important for larger individuals as fish size was positively correlated with air exposure (Pearson’s r coefficient = 0.41, p < 0.01) and fight times (0.88, p < 0.01). The findings suggest that recreational C&R may result in mortalities directly, via C&R, and indirectly, via predation, and several recommendations were made for best practice. Chapter 6 aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary. Results indicated that the recreational fishery for contributed significantly to the economy of an area that would otherwise likely receive little external input ($282 054 per four-month fishing season). However, high rates of economic leakage from the study area were identified (58.7%–92.9% of locally spent revenue) and were attributed to the sourcing of lodge supplies, services and staff outside of the local area and the repatriation of profit by foreign business owners. Capacity building within the local community is likely required to develop ‘linkages’ between the local community and the recreational fishery. Greater community involvement in the fishery is suggested to incentivise the protection of recreationally important fishery species and their associated ecosystems. Chapter 7 aimed to investigate the resource user groups involved within the SES. Results illustrated that artisanal and domestic recreational anglers are well-established and are characterised by long histories of participation. The artisanal fishery was highly valued as a source of livelihoods for the local community. Artisanal fishers were eager for involvement in the recreational sector, through the chartering of their vessels, due to the attractiveness of extra earnings. Both recreational and artisanal fishers reported recent decreases in P. quadrifilis catch and anticipated further declines. Domestic recreational anglers appeared to be highly consumptive in their use of the fishery and C&R angling was uncommon. User conflict may be problematic for future management as recreational anglers perceived the artisanal gill-net fishery to be a threat towards P. quadrifilis stocks. In conclusion, the open-access nature of the fishery was identified as the most pertinent threat to its sustainability and likely needs to be addressed. Potential solutions involve offering users the opportunity to purchase access rights (e.g. day permits), thus initiating the concept that users must pay for their use of public resources. Management should aim to protect large female fish due to their increased reproductive value and worth as trophy fish. Thus, C&R angling is likely to be an important interaction between users and the resource. However, angler behaviour will need to be manipulated to promote C&R and minimise C&R-related mortalities. Solutions include angler educational drives and interventions and the implementation of competitive C&R-only angling. Foreign recreational fisheries, although touted as potential ecotourism ventures, will only succeed in improving the lives of local people if they fully integrate the community into the operation of the fishery.
- Full Text:
- Date Issued: 2020