The effectiveness of networking and collaboration in creative hubs: a case of Hub@Goethe
- Authors: De Beer, Magdalena Gertruda
- Date: 2022-04-06
- Subjects: Cultural industries South Africa , Cultural industries Economic aspects South Africa , Economic development projects South Africa , Social entrepreneurship South Africa , Creative ability Economic aspects South Africa , Social capital (Sociology) South Africa , Social networks South Africa , Hub@Goethe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284504 , vital:56069
- Description: This research took the form of a case study investigating the effectiveness of a single hub in South Africa, namely Hub@Goethe in Johannesburg. The context of the creative economy and creative industries provided insight into the experiences of creative cultural labourers in the new economic model. The context emphasised the research problem which considered the difficulties experienced by creative and cultural entrepreneurs and their career paths who, through labour precarity, remain isolated from the market, without access to physical spaces, network connections and business knowledge to realise their business ideas. The literature reviewed revealed how co-working office spaces, creative spaces and hubs provide creative entrepreneurs with the spatial infrastructure, amenities, and network access to mitigate challenges in the creative cultural sectors. These spaces offer a multitude of different amenities which is specific to their community’s needs. Guided by the theory of social capital and structural holes reviewed in the literature, the effectiveness was assessed by the hub’s ability to provide network access benefits or resource endowments. The research looked at whether the hub could provide creative cultural entrepreneurs with resource benefits such as a) access to social interactions, collaboration, and knowledge sharing, b) access to business or professional skills-based education programmes and mentorship, c) access to market and d) generation both social and economic benefit. The research adopted a qualitative approach, seeking insights into the creative entrepreneurs’ experiences at the hub utilising one-to-one interviews. The thematic analysis confirmed that the hub was effective overall in providing entrepreneurs with access to benefits or resource endowments embedded in the network, confirming that hubs may be an effective tool in mitigating difficulties experienced by creative entrepreneurs in the creative industries. The research also showed areas of improvement where the hub could increase its experienced effectiveness, especially in reference to routes to market. The research findings inferred the importance of physical space, proximity and accessibility has on collaborative practices amongst creative entrepreneurs within the hub space. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Authors: De Beer, Magdalena Gertruda
- Date: 2022-04-06
- Subjects: Cultural industries South Africa , Cultural industries Economic aspects South Africa , Economic development projects South Africa , Social entrepreneurship South Africa , Creative ability Economic aspects South Africa , Social capital (Sociology) South Africa , Social networks South Africa , Hub@Goethe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284504 , vital:56069
- Description: This research took the form of a case study investigating the effectiveness of a single hub in South Africa, namely Hub@Goethe in Johannesburg. The context of the creative economy and creative industries provided insight into the experiences of creative cultural labourers in the new economic model. The context emphasised the research problem which considered the difficulties experienced by creative and cultural entrepreneurs and their career paths who, through labour precarity, remain isolated from the market, without access to physical spaces, network connections and business knowledge to realise their business ideas. The literature reviewed revealed how co-working office spaces, creative spaces and hubs provide creative entrepreneurs with the spatial infrastructure, amenities, and network access to mitigate challenges in the creative cultural sectors. These spaces offer a multitude of different amenities which is specific to their community’s needs. Guided by the theory of social capital and structural holes reviewed in the literature, the effectiveness was assessed by the hub’s ability to provide network access benefits or resource endowments. The research looked at whether the hub could provide creative cultural entrepreneurs with resource benefits such as a) access to social interactions, collaboration, and knowledge sharing, b) access to business or professional skills-based education programmes and mentorship, c) access to market and d) generation both social and economic benefit. The research adopted a qualitative approach, seeking insights into the creative entrepreneurs’ experiences at the hub utilising one-to-one interviews. The thematic analysis confirmed that the hub was effective overall in providing entrepreneurs with access to benefits or resource endowments embedded in the network, confirming that hubs may be an effective tool in mitigating difficulties experienced by creative entrepreneurs in the creative industries. The research also showed areas of improvement where the hub could increase its experienced effectiveness, especially in reference to routes to market. The research findings inferred the importance of physical space, proximity and accessibility has on collaborative practices amongst creative entrepreneurs within the hub space. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
The effects of temperature and exploitation on the behaviour of red roman Chrysoblephus laticeps (Sparidae) at baited video stations
- Authors: Mataboge, Bontle Boitumelo
- Date: 2022-04-06
- Subjects: Marine resources conservation South Africa Agulhas , Sparidae Effect of temperature on South Africa Agulhas , Sparidae Climatic factors South Africa Agulhas , Sparidae Effect of fishing on South Africa Agulhas , Sparidae Effect of human beings on South Africa Agulhas , Sparidae Behavior South Africa Agulhas , Overfishing South Africa Agulhas , Underwater videography in wildlife monitoring South Africa Agulhas , Red roman (Chrysoblephus laticeps)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291140 , vital:56823
- Description: Marine environments are experiencing rapidly increasing temperatures, sea levels and acidification and higher frequencies and magnitudes of extreme weather events as a result of climate change. In the Agulhas Ecoregion of South Africa, there has been an increase in the frequency and intensity of upwelling events. Upwelling events result in rapid and large decreases in water temperature which can persist for several days. Variation in water temperature is known to impact the metabolic rate of fish (which are ectotherms) and in turn their activity patterns. To promote fitness related traits, the metabolic rate of fish is maximised at a specific temperature range. Outside of this optimal temperature range, the capacity of fish to perform aerobically declines. Therefore, it is expected that an increase in upwelling may place the fish under significant physiological stress. The effects of climate change can be compounded by the effects of fisheries-induced evolution; the microevolution of a fish population due to the artificial selection of certain biological traits by fishing practices. Passive fishing gears preferentially remove large (older) and bold individuals, causing reductions in population size, genetic diversity and fecundity as well as size and age truncation and the loss of large, bold and dominant phenotypes in fish populations. These demographic changes affect the adaptive capacity of fish and exploited populations are expected to be less resilient to climate variability and long-term temperature change. The resilience of fish is largely dependent on their physiological attributes, particularly their metabolic rate. Theoretically, fish with broader aerobic scope (defined as the difference between an individual’s maximum metabolic rate and standard metabolic rate) will be more tolerant to the impacts of climate change as they have energy available for adaptation. Recent respirometry and accelerometry studies suggest that populations of the endemic southern African linefish Chrysoblephus laticeps (red roman) from inside marine protected areas (MPAs) have higher metabolic rates and broader aerobic scope compared to those found outside of MPAs, particularly at thermal extremes. As C. laticeps are highly resident it is possible that fish populations protected within well-established MPAs may be more resilient to the physiological stresses caused by upwelling if they are able to maintain their activity levels despite changing temperatures. Behaviour is a proxy that can be used to infer metabolism as behaviours have associated metabolic costs and benefits. Behaviour is also a trait that can be altered by passive fishing practices which preferentially extract more active and bold individuals. Given this context, the aim of this thesis was to determine the effects of short-term thermal variability on the population structure and behaviour of C. laticeps and whether these effects differed between protected and exploited populations. Baited remote underwater stereo-video systems (stereo-BRUVs) were used to observe C. laticeps inside two MPAs (Tsitsikamma and Goukamma) and at two exploited sites (Port Elizabeth and Cape St. Francis) over the temperature range 10-18 °C. The relative abundance, size and relevant behaviours of C. laticeps were recorded. The relative abundance (MaxN) of C. laticeps was not significantly higher inside the MPAs compared to the exploited sites. The size of C. laticeps did not vary significantly by protection level either. However, the mean size of C. laticeps was considerably smaller at Port Elizabeth compared to the three other locations. There was a notable absence of large C. laticeps size classes at Port Elizabeth. The effect of water temperature on relative abundance was only seen in the exploited areas, where temperature and abundance were positively correlated. This was not the case in the protected areas where C. laticeps abundance remained roughly consistent. Generally, the effect of temperature on all measured behaviours was consistent across protection levels. An exception was that the feeding rate at Tsitsikamma MPA was significantly higher than at Cape St. Francis at temperatures below 11.5 °C. Temperature had a significant effect on the time taken for the first individual to appear in the field of view. This time shortened with increasing temperature, regardless of protection level. This was likely a result of the metabolic constraints placed on individuals by low waters temperatures and individuals would be able to pursue the bait more readily at higher temperatures. However, there was no evidence of greater metabolic scope from the C. laticeps individuals observed in the MPAs, relative to the exploited areas. Individual size and the presence of conspecifics were also found to significantly influence behaviour. Generally, size had a positive relationship with behaviour, with larger individuals more likely to feed on the bait, chase other fish from the bait (only in the MPAs) and spend more time in the field of view. The higher displays of aggression in MPAs may be an indication of fishing practices having removed bold and dominant individuals at the exploited sites. The probability of fleeing and the feeding rates of individuals increased with increasing numbers of conspecifics, suggesting that C. laticeps behaviour is influenced by intraspecific competition. Overall, this thesis did not find strong evidence that C. laticeps from MPAs performed better than C. laticeps from exploited areas, even at low temperatures. Behavioural responses to temperature were highly variable across locations and this may be attributed to high behavioural phenotypic diversity among individuals. Environmental stressors, such as temperature changes, can illicit very different behavioural responses among individuals in a population. It is also possible that C. laticeps from the exploited areas have the same genetic predispositions to physiological stress as the individuals in the MPAs due to spillover and larval recruitment from the MPAs. Indeed, genetic studies find that all C. laticeps population in South African represent a single well-mixed genetic stock. It is likely that greater sampling effort is required to resolve the patterns in behaviour between exploited and protected populations. Nonetheless, given the influence of size on behaviour, the smaller size of C. laticeps at Port Elizabeth may be cause for concern regarding the vulnerability of future populations to ongoing climate change. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Authors: Mataboge, Bontle Boitumelo
- Date: 2022-04-06
- Subjects: Marine resources conservation South Africa Agulhas , Sparidae Effect of temperature on South Africa Agulhas , Sparidae Climatic factors South Africa Agulhas , Sparidae Effect of fishing on South Africa Agulhas , Sparidae Effect of human beings on South Africa Agulhas , Sparidae Behavior South Africa Agulhas , Overfishing South Africa Agulhas , Underwater videography in wildlife monitoring South Africa Agulhas , Red roman (Chrysoblephus laticeps)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291140 , vital:56823
- Description: Marine environments are experiencing rapidly increasing temperatures, sea levels and acidification and higher frequencies and magnitudes of extreme weather events as a result of climate change. In the Agulhas Ecoregion of South Africa, there has been an increase in the frequency and intensity of upwelling events. Upwelling events result in rapid and large decreases in water temperature which can persist for several days. Variation in water temperature is known to impact the metabolic rate of fish (which are ectotherms) and in turn their activity patterns. To promote fitness related traits, the metabolic rate of fish is maximised at a specific temperature range. Outside of this optimal temperature range, the capacity of fish to perform aerobically declines. Therefore, it is expected that an increase in upwelling may place the fish under significant physiological stress. The effects of climate change can be compounded by the effects of fisheries-induced evolution; the microevolution of a fish population due to the artificial selection of certain biological traits by fishing practices. Passive fishing gears preferentially remove large (older) and bold individuals, causing reductions in population size, genetic diversity and fecundity as well as size and age truncation and the loss of large, bold and dominant phenotypes in fish populations. These demographic changes affect the adaptive capacity of fish and exploited populations are expected to be less resilient to climate variability and long-term temperature change. The resilience of fish is largely dependent on their physiological attributes, particularly their metabolic rate. Theoretically, fish with broader aerobic scope (defined as the difference between an individual’s maximum metabolic rate and standard metabolic rate) will be more tolerant to the impacts of climate change as they have energy available for adaptation. Recent respirometry and accelerometry studies suggest that populations of the endemic southern African linefish Chrysoblephus laticeps (red roman) from inside marine protected areas (MPAs) have higher metabolic rates and broader aerobic scope compared to those found outside of MPAs, particularly at thermal extremes. As C. laticeps are highly resident it is possible that fish populations protected within well-established MPAs may be more resilient to the physiological stresses caused by upwelling if they are able to maintain their activity levels despite changing temperatures. Behaviour is a proxy that can be used to infer metabolism as behaviours have associated metabolic costs and benefits. Behaviour is also a trait that can be altered by passive fishing practices which preferentially extract more active and bold individuals. Given this context, the aim of this thesis was to determine the effects of short-term thermal variability on the population structure and behaviour of C. laticeps and whether these effects differed between protected and exploited populations. Baited remote underwater stereo-video systems (stereo-BRUVs) were used to observe C. laticeps inside two MPAs (Tsitsikamma and Goukamma) and at two exploited sites (Port Elizabeth and Cape St. Francis) over the temperature range 10-18 °C. The relative abundance, size and relevant behaviours of C. laticeps were recorded. The relative abundance (MaxN) of C. laticeps was not significantly higher inside the MPAs compared to the exploited sites. The size of C. laticeps did not vary significantly by protection level either. However, the mean size of C. laticeps was considerably smaller at Port Elizabeth compared to the three other locations. There was a notable absence of large C. laticeps size classes at Port Elizabeth. The effect of water temperature on relative abundance was only seen in the exploited areas, where temperature and abundance were positively correlated. This was not the case in the protected areas where C. laticeps abundance remained roughly consistent. Generally, the effect of temperature on all measured behaviours was consistent across protection levels. An exception was that the feeding rate at Tsitsikamma MPA was significantly higher than at Cape St. Francis at temperatures below 11.5 °C. Temperature had a significant effect on the time taken for the first individual to appear in the field of view. This time shortened with increasing temperature, regardless of protection level. This was likely a result of the metabolic constraints placed on individuals by low waters temperatures and individuals would be able to pursue the bait more readily at higher temperatures. However, there was no evidence of greater metabolic scope from the C. laticeps individuals observed in the MPAs, relative to the exploited areas. Individual size and the presence of conspecifics were also found to significantly influence behaviour. Generally, size had a positive relationship with behaviour, with larger individuals more likely to feed on the bait, chase other fish from the bait (only in the MPAs) and spend more time in the field of view. The higher displays of aggression in MPAs may be an indication of fishing practices having removed bold and dominant individuals at the exploited sites. The probability of fleeing and the feeding rates of individuals increased with increasing numbers of conspecifics, suggesting that C. laticeps behaviour is influenced by intraspecific competition. Overall, this thesis did not find strong evidence that C. laticeps from MPAs performed better than C. laticeps from exploited areas, even at low temperatures. Behavioural responses to temperature were highly variable across locations and this may be attributed to high behavioural phenotypic diversity among individuals. Environmental stressors, such as temperature changes, can illicit very different behavioural responses among individuals in a population. It is also possible that C. laticeps from the exploited areas have the same genetic predispositions to physiological stress as the individuals in the MPAs due to spillover and larval recruitment from the MPAs. Indeed, genetic studies find that all C. laticeps population in South African represent a single well-mixed genetic stock. It is likely that greater sampling effort is required to resolve the patterns in behaviour between exploited and protected populations. Nonetheless, given the influence of size on behaviour, the smaller size of C. laticeps at Port Elizabeth may be cause for concern regarding the vulnerability of future populations to ongoing climate change. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
The elucidation of nickel and zinc based Metal Organic Frameworks (MOFs) using a polycarboxylate-benzene ligand: a synthetic, spectroscopic, and thermoanalytical study
- Authors: Hodgson, Ivan Mark
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290877 , vital:56795
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Authors: Hodgson, Ivan Mark
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290877 , vital:56795
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
The geology, mineralogy, structure and economic aspects of the pegmatite-hosted Swanson Tantalum Deposit, Tantalite Valley area, southern Namibia
- Authors: Pepler, Laubser
- Date: 2022-04-06
- Subjects: Pegmatites South Africa Pofadder (Region) , Tantalum South Africa Pofadder (Region) , Geology South Africa Pofadder (Region) , Mineralogy South Africa Pofadder (Region) , Pegmatites South Africa Pofadder (Region) Structure , Pegmatites Economic aspects South Africa Pofadder (Region) , Pofadder Shear Zone , Tantalite Valley Complex , Orange River Pegmatite Belt , Lower Fish River/Onseepkans Thrust Zone
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291303 , vital:56843
- Description: This study presents the geology, mineralogy, structure, and economic aspects of the recently explored Swanson Tantalum Deposit occurring within the Namaqua Sector of the Namaqua Natal Metamorphic Province, Tantalite Valley area, southern Namibia. It is an LCT-type pegmatite hosted (microlitetantalite- tapiolite ± spodumene – lepidolite - zinnwaldite) tantalum deposit forming part of a highly localised sill-and-dyke swarm comprised of 15 shallow dipping and significantly mineralised pegmatites. This deposit forms part of the western portions of the regionally developed∼ 1040 – 950 Ma Orange River Pegmatite Belt (ORPB) which was locally emplaced syn-tectonically into competent host rocks in the core zone of the late-stage crustal scale transcurrent dextral, ductile to brittle-ductile D4 Marshall Rocks – Pofadder Shear Zone (MRPSZ), where it crosscuts the rocks of the D2 Lower Fish River - Onseepkans Thrust Zone (LFROTZ). A JORC Maiden Mineral Resource of 1.2 Mt @ 412 ppm Ta2O5 + 76 ppm Nb2O5 + 0.29 wt. % Li2O (with an applied cut-off grade of 236 ppm Ta2O5 and a minimum thickness of 1 m) has recently been estimated for the deposit. The deposit is currently being advanced to feasibility stage with the aim of outlining economic Mineral Reserves. It currently hosts a globally significant and market-relevant “high grade – low tonnage” tantalum Mineral Resource. Recent litho-structural mapping of this deposit has shown that its structural setting encompasses a locally developed lower strain extensional quadrant associated with the mega-scale shear zone bound competent mantle porphyroclast: the mafic-ultramafic Tantalite Valley Complex (TVC), or TVC megaclast. A succession of syn-D4 MRPSZ-hosted granitic melts comprising earlier leucogranite intrusions and later mineralised pegmatites of the Swanson Tantalum Deposit have variably utilised this extensional structure. The earlier leucogranites have clearly exploited mylonitic foliations associated with the development of core zone of the MRPSZ, while the mineralised pegmatites have utilised later-stage shallow-dipping Riedel fractures developed within more competent host rock. The tantalum tenor of pegmatites comprising the Swanson Tantalum Deposit is clearly structurally controlled, with tantalum tenor increasing from NW towards the SE over relatively short distances, toward the TVC megaclast. Although highly speculative without robust geochronological and petrographic investigation, field observations from this study highlights that the host rocks to the Swanson Tantalum Deposit, namely the mottled hybrid metagabbro (HMG), usually described as being syn-D2 in age (∼ 1200 – 1100 Ma), may possibly be syn-D4 in age (∼ 1040 – 950 Ma). If this is proven to be true, it may represent the earliest syn-D4 melt known for the MRPSZ. The Swanson Tantalum Deposit area therefore represents a prime area for studying and potentially constraining the upper and lower age limits of the MRPSZ. , Thesis (MSc) -- Faculty of Science, Geology, 2022
- Full Text:
- Authors: Pepler, Laubser
- Date: 2022-04-06
- Subjects: Pegmatites South Africa Pofadder (Region) , Tantalum South Africa Pofadder (Region) , Geology South Africa Pofadder (Region) , Mineralogy South Africa Pofadder (Region) , Pegmatites South Africa Pofadder (Region) Structure , Pegmatites Economic aspects South Africa Pofadder (Region) , Pofadder Shear Zone , Tantalite Valley Complex , Orange River Pegmatite Belt , Lower Fish River/Onseepkans Thrust Zone
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291303 , vital:56843
- Description: This study presents the geology, mineralogy, structure, and economic aspects of the recently explored Swanson Tantalum Deposit occurring within the Namaqua Sector of the Namaqua Natal Metamorphic Province, Tantalite Valley area, southern Namibia. It is an LCT-type pegmatite hosted (microlitetantalite- tapiolite ± spodumene – lepidolite - zinnwaldite) tantalum deposit forming part of a highly localised sill-and-dyke swarm comprised of 15 shallow dipping and significantly mineralised pegmatites. This deposit forms part of the western portions of the regionally developed∼ 1040 – 950 Ma Orange River Pegmatite Belt (ORPB) which was locally emplaced syn-tectonically into competent host rocks in the core zone of the late-stage crustal scale transcurrent dextral, ductile to brittle-ductile D4 Marshall Rocks – Pofadder Shear Zone (MRPSZ), where it crosscuts the rocks of the D2 Lower Fish River - Onseepkans Thrust Zone (LFROTZ). A JORC Maiden Mineral Resource of 1.2 Mt @ 412 ppm Ta2O5 + 76 ppm Nb2O5 + 0.29 wt. % Li2O (with an applied cut-off grade of 236 ppm Ta2O5 and a minimum thickness of 1 m) has recently been estimated for the deposit. The deposit is currently being advanced to feasibility stage with the aim of outlining economic Mineral Reserves. It currently hosts a globally significant and market-relevant “high grade – low tonnage” tantalum Mineral Resource. Recent litho-structural mapping of this deposit has shown that its structural setting encompasses a locally developed lower strain extensional quadrant associated with the mega-scale shear zone bound competent mantle porphyroclast: the mafic-ultramafic Tantalite Valley Complex (TVC), or TVC megaclast. A succession of syn-D4 MRPSZ-hosted granitic melts comprising earlier leucogranite intrusions and later mineralised pegmatites of the Swanson Tantalum Deposit have variably utilised this extensional structure. The earlier leucogranites have clearly exploited mylonitic foliations associated with the development of core zone of the MRPSZ, while the mineralised pegmatites have utilised later-stage shallow-dipping Riedel fractures developed within more competent host rock. The tantalum tenor of pegmatites comprising the Swanson Tantalum Deposit is clearly structurally controlled, with tantalum tenor increasing from NW towards the SE over relatively short distances, toward the TVC megaclast. Although highly speculative without robust geochronological and petrographic investigation, field observations from this study highlights that the host rocks to the Swanson Tantalum Deposit, namely the mottled hybrid metagabbro (HMG), usually described as being syn-D2 in age (∼ 1200 – 1100 Ma), may possibly be syn-D4 in age (∼ 1040 – 950 Ma). If this is proven to be true, it may represent the earliest syn-D4 melt known for the MRPSZ. The Swanson Tantalum Deposit area therefore represents a prime area for studying and potentially constraining the upper and lower age limits of the MRPSZ. , Thesis (MSc) -- Faculty of Science, Geology, 2022
- Full Text:
The host specificity and efficacy of Phenrica guerini (Bechyné) (Coleoptera: Chrysomelidae), a candidate biological control agent of Pereskia aculeata Miller (Cactaceae) in Australia
- Authors: Dixon, Elizabeth Anne
- Date: 2022-04-06
- Subjects: Chrysomelidae Australia , Pereskia Australia , Pereskia Biological control Australia , Invasive plants Biological control Australia , Insects as biological pest control agents Australia , Cactus Biological control Australia
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290826 , vital:56789
- Description: Pereskia aculeata Miller (Cactaceae) is a primitive creeping cactus that originated from South America and has become an invasive alien plant in South Africa and Australia. Due to its vine-like growth form mechanical and chemical control are not feasible options for its control, therefore biological control is the best option for controlling this plant. Phenrica guerini (Bechyné) (Chrysomelidae) is a leaf-feeding flea beetle that has been released as a biological control agent against Pe. aculeata in South Africa and has been shown to be damaging at some sites in the country. In this thesis, further studies into the use of Ph. guerini as a biological control agent against Pe. aculeata were conducted to determine whether the beetle should be released as an agent against the target weed in Australia. The host range of a potential biological control agent is important to determine as only monophagous agents, or agents with suitably restricted host ranges, should be considered for release. Host specificity testing was conducted to determine if Ph. guerini was suitably specific for release in Australia. Phenrica guerini larvae only fed and partially developed on three out of 25 test plants, but failed to pupate on any plants besides Pe. aculeata. Adult beetles did not feed on any test plants and only oviposited on one test plant species. Phenrica guerini did not develop on any plant other than the target weed and is therefore suitably host specific for release in Australia. The efficacy of a potential agent is also important to consider as the release of an ineffective agent can reduce the success of a biological control programme. A laboratory based pre-release efficacy assessment was done to determine the impact that Ph. guerini could have on Pe. aculeata. There was a significant difference between the control plants and those with larvae, with an average of 72 (S.E. ± 12.33) less leaves on plants with feeding and the main stem of the plant being 11.1 cm (S.E. ± 7.17) shorter. Although there were no significant differences observed in the number of additional stems, and weights of the different plant parts, this was not a long term study and many of these differences would not have been observed in a short period. Based on the impact observed on the leaves and the main stem, and various field studies that have been done to assess the impact of Ph. guerini on Pe. aculeata in the field in South Africa, Ph. guerini appears to be a potentially damaging agent. As Pe. aculeata is still in its early stages of invasion in Australia the beetle has the potential to be damaging and reduce the invasion trajectory of the plant. This study showed that the beetle is suitably host specific and potentially damaging enough to be recommended for release as a biological control agent against Pe. aculeata in Australia. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Authors: Dixon, Elizabeth Anne
- Date: 2022-04-06
- Subjects: Chrysomelidae Australia , Pereskia Australia , Pereskia Biological control Australia , Invasive plants Biological control Australia , Insects as biological pest control agents Australia , Cactus Biological control Australia
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290826 , vital:56789
- Description: Pereskia aculeata Miller (Cactaceae) is a primitive creeping cactus that originated from South America and has become an invasive alien plant in South Africa and Australia. Due to its vine-like growth form mechanical and chemical control are not feasible options for its control, therefore biological control is the best option for controlling this plant. Phenrica guerini (Bechyné) (Chrysomelidae) is a leaf-feeding flea beetle that has been released as a biological control agent against Pe. aculeata in South Africa and has been shown to be damaging at some sites in the country. In this thesis, further studies into the use of Ph. guerini as a biological control agent against Pe. aculeata were conducted to determine whether the beetle should be released as an agent against the target weed in Australia. The host range of a potential biological control agent is important to determine as only monophagous agents, or agents with suitably restricted host ranges, should be considered for release. Host specificity testing was conducted to determine if Ph. guerini was suitably specific for release in Australia. Phenrica guerini larvae only fed and partially developed on three out of 25 test plants, but failed to pupate on any plants besides Pe. aculeata. Adult beetles did not feed on any test plants and only oviposited on one test plant species. Phenrica guerini did not develop on any plant other than the target weed and is therefore suitably host specific for release in Australia. The efficacy of a potential agent is also important to consider as the release of an ineffective agent can reduce the success of a biological control programme. A laboratory based pre-release efficacy assessment was done to determine the impact that Ph. guerini could have on Pe. aculeata. There was a significant difference between the control plants and those with larvae, with an average of 72 (S.E. ± 12.33) less leaves on plants with feeding and the main stem of the plant being 11.1 cm (S.E. ± 7.17) shorter. Although there were no significant differences observed in the number of additional stems, and weights of the different plant parts, this was not a long term study and many of these differences would not have been observed in a short period. Based on the impact observed on the leaves and the main stem, and various field studies that have been done to assess the impact of Ph. guerini on Pe. aculeata in the field in South Africa, Ph. guerini appears to be a potentially damaging agent. As Pe. aculeata is still in its early stages of invasion in Australia the beetle has the potential to be damaging and reduce the invasion trajectory of the plant. This study showed that the beetle is suitably host specific and potentially damaging enough to be recommended for release as a biological control agent against Pe. aculeata in Australia. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
The impact of the hybridisation of dactylopius opuntiae cockerell cochineal lineages on the biological control of cactus weeds
- Authors: Mofokeng, Kedibone
- Date: 2022-04-06
- Subjects: Dactylopius South Africa Eastern Cape , Cochineal insect South Africa Eastern Cape , Opuntia South Africa Eastern Cape , Dactylopius Hybridization South Africa Eastern Cape , Insect-plant relationships , Weeds Biological control South Africa Eastern Cape , Host affinity
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232466 , vital:49994
- Description: In an attempt to control the harmful invasive alien plant, Opuntia megapotamica Arechav. (Cactaceae), a population of the cochineal insect Dactylopius opuntiae Cockerell (Dactylopiidae) (known as the ‘engelmannii’ lineage) is being considered as a potential biological control agent. This lineage of cochineal and the already established ‘ficus’ and ‘stricta’ lineages of the same cochineal species will inevitably hybridise where they occur in sympatry, possibly influencing the efficacy of the lineages on their respective hosts. Laboratory studies were conducted to investigate the likely outcomes of hybridisation between the ‘engelmannii’ and ‘ficus’ lineages. Detailed hybridisation trials, during which individual insects were manipulated and crossed, were used to compare the host affinity of F₁ and F₂ hybrids between the ‘ficus’ and ‘engelmannii’ lineages with the host specificity of the two pure-bred lineages. Host affinity was determined by plotting the net rate of increase (R) of a cochineal population developing on one host plant species against R on the other host plant species. F₁ hybrids were less species-specific than the purebred lineages in both crosses. Thus, the first generation will most likely remain effective in controlling both plant species in the field. F₂ hybrids produced a mixture of purebred and hybrid genotypes, with a higher net rate of increase when compared to purebred nymphs on their alternative host. Biological control of both Opuntia ficus-indica (L.) Mill. (Cactaceae) and O. megapotamica in the Eastern Cape Province, where both invasive alien plant species occur together, could be enhanced by the less specific nature of the F₁ progeny, which developed equally well on both O. megapotamica and O. ficus-indica; but this benefit will be reduced by the loss of host specificity of F₂ progeny. The success of biological control would depend on whether the species-specific nymph encounters its target host, because the less specific nymphs will have little effect on controlling either weed. These findings indicate that only purebred D. opuntiae lineages should be released in monocultures of their targeted weed. Long-term consequences of hybridisation should be monitored in the field. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Authors: Mofokeng, Kedibone
- Date: 2022-04-06
- Subjects: Dactylopius South Africa Eastern Cape , Cochineal insect South Africa Eastern Cape , Opuntia South Africa Eastern Cape , Dactylopius Hybridization South Africa Eastern Cape , Insect-plant relationships , Weeds Biological control South Africa Eastern Cape , Host affinity
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232466 , vital:49994
- Description: In an attempt to control the harmful invasive alien plant, Opuntia megapotamica Arechav. (Cactaceae), a population of the cochineal insect Dactylopius opuntiae Cockerell (Dactylopiidae) (known as the ‘engelmannii’ lineage) is being considered as a potential biological control agent. This lineage of cochineal and the already established ‘ficus’ and ‘stricta’ lineages of the same cochineal species will inevitably hybridise where they occur in sympatry, possibly influencing the efficacy of the lineages on their respective hosts. Laboratory studies were conducted to investigate the likely outcomes of hybridisation between the ‘engelmannii’ and ‘ficus’ lineages. Detailed hybridisation trials, during which individual insects were manipulated and crossed, were used to compare the host affinity of F₁ and F₂ hybrids between the ‘ficus’ and ‘engelmannii’ lineages with the host specificity of the two pure-bred lineages. Host affinity was determined by plotting the net rate of increase (R) of a cochineal population developing on one host plant species against R on the other host plant species. F₁ hybrids were less species-specific than the purebred lineages in both crosses. Thus, the first generation will most likely remain effective in controlling both plant species in the field. F₂ hybrids produced a mixture of purebred and hybrid genotypes, with a higher net rate of increase when compared to purebred nymphs on their alternative host. Biological control of both Opuntia ficus-indica (L.) Mill. (Cactaceae) and O. megapotamica in the Eastern Cape Province, where both invasive alien plant species occur together, could be enhanced by the less specific nature of the F₁ progeny, which developed equally well on both O. megapotamica and O. ficus-indica; but this benefit will be reduced by the loss of host specificity of F₂ progeny. The success of biological control would depend on whether the species-specific nymph encounters its target host, because the less specific nymphs will have little effect on controlling either weed. These findings indicate that only purebred D. opuntiae lineages should be released in monocultures of their targeted weed. Long-term consequences of hybridisation should be monitored in the field. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
The impact of urban gardening on household food security: evidence from Makhanda East, Eastern Cape Province, South Africa
- Bruwer, Guillaume Marcel Xavier
- Authors: Bruwer, Guillaume Marcel Xavier
- Date: 2022-04-06
- Subjects: Food security South Africa Makhanda , Urban agriculture South Africa Makhanda , Urban gardening South Africa Makhanda , Sustainable development South Africa Makhanda , South Africa Economic conditions , Subsistence farming South Africa Makhanda , Economic impact analysis South Africa Makhanda , Propensity Score Matching (PSM)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263575 , vital:53640
- Description: Urban gardening in townships is a common coping strategy employed by poor inhabitants to improve food security, earn income through sales, and generate cost-savings through home consumption of fresh produce. Food security is a cornerstone of human development and welfare, and the achievement thereof remains a global challenge. The majority of academic research and policy documentation traditionally positions food insecurity as a rural phenomenon. However, recent trends point to an increase in food insecurity in urban areas, particularly in low-income areas such as townships. In South Africa, rapid urbanization has led to burgeoning townships and rapidly expanding low-income informal settlements characterised by poverty, unemployment, and food insecurity. Research concerned with the role that urban agricultural production plays in contributing to the food security of poor households is scarce and not well understood. This research, therefore, aimed to contribute to the limited research which specifically examines urban food security, and the role urban agriculture play in the achievement of household food security. The study employed collective action theory and utility theory to firstly provides an in-depth examination of the determinants of participation in urban gardening using Probit regression modeling. The second research objective was to perform an impact evaluation of participation in urban gardening on selected household food security indicators including Household Dietary Diversity Scores (HDDS), the Household Hunger Scale (HHS) and the Coping Strategy Index (CSI) using Propensity Score Matching (PSM). Purposive and snowball sampling methods were employed to obtain a sample of 60 urban gardeners and a control group of 55 non-gardening households from Extension 6, 7 and 10 townships as well as Joza Location in Makhanda East, Eastern Cape Province. Households were surveyed using a structured household food security questionnaire. A focus group discussion was held with the Linomtha Community Garden members and key informant interviews were undertaken with important stakeholders such as the local extension officers. Descriptive analysis revealed that urban gardening households (UGs) had older household heads who were less educated, and that land and water availability were the dominant constraints to increases in agricultural production. Results from the probit and average marginal effects models showed that the likelihood of participation significantly increased when household unemployment and dependency increased and that households who were engaged in off-farm economic activity were more likely to participate in urban gardening. The impact evaluation was performed using PSM and Average Treatment Effect on the Treated (ATT). Analysis illustrated that participation in urban gardening does significantly reduce both the full CSI and Reduced CSI. Thus, participation in urban gardening improves the food security of participating households by significantly reducing the frequency of participating households (UGs) applying undesirable coping strategies such as sending children elsewhere other than the household, borrowing food from other households and reducing the number of meals eaten in a day due to food shortages. This study posits that urban gardening alone will not eradicate the rampant food insecurity and poverty which pervades in South Africa’s townships. However, urban gardening participation does contribute to the construction of a sustainable, urban livelihood by reducing the number and severity of the undesirable coping strategies that food insecure households employ by providing some nutritious produce as well improved social capital through gardening networks and supporting institutions. It is recommended that policy makers, at a national and municipal level, need to create a clearer directive for the integration of urban food production into the urban food marketplace thus increasing access to income generating channels for small-scale home, and community gardeners. Co-operation between private and public institutions for food security and urban gardeners needs to be fostered and awareness of opportunities to participate in urban gardens needs to be improved. Central to the developmental challenges that rapid increases in urbanization and food insecurity in poor urban areas, is the need for national and local governments to improve access to economic opportunities in township areas - both in urban agriculture and in other, skills intensive sectors. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Authors: Bruwer, Guillaume Marcel Xavier
- Date: 2022-04-06
- Subjects: Food security South Africa Makhanda , Urban agriculture South Africa Makhanda , Urban gardening South Africa Makhanda , Sustainable development South Africa Makhanda , South Africa Economic conditions , Subsistence farming South Africa Makhanda , Economic impact analysis South Africa Makhanda , Propensity Score Matching (PSM)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263575 , vital:53640
- Description: Urban gardening in townships is a common coping strategy employed by poor inhabitants to improve food security, earn income through sales, and generate cost-savings through home consumption of fresh produce. Food security is a cornerstone of human development and welfare, and the achievement thereof remains a global challenge. The majority of academic research and policy documentation traditionally positions food insecurity as a rural phenomenon. However, recent trends point to an increase in food insecurity in urban areas, particularly in low-income areas such as townships. In South Africa, rapid urbanization has led to burgeoning townships and rapidly expanding low-income informal settlements characterised by poverty, unemployment, and food insecurity. Research concerned with the role that urban agricultural production plays in contributing to the food security of poor households is scarce and not well understood. This research, therefore, aimed to contribute to the limited research which specifically examines urban food security, and the role urban agriculture play in the achievement of household food security. The study employed collective action theory and utility theory to firstly provides an in-depth examination of the determinants of participation in urban gardening using Probit regression modeling. The second research objective was to perform an impact evaluation of participation in urban gardening on selected household food security indicators including Household Dietary Diversity Scores (HDDS), the Household Hunger Scale (HHS) and the Coping Strategy Index (CSI) using Propensity Score Matching (PSM). Purposive and snowball sampling methods were employed to obtain a sample of 60 urban gardeners and a control group of 55 non-gardening households from Extension 6, 7 and 10 townships as well as Joza Location in Makhanda East, Eastern Cape Province. Households were surveyed using a structured household food security questionnaire. A focus group discussion was held with the Linomtha Community Garden members and key informant interviews were undertaken with important stakeholders such as the local extension officers. Descriptive analysis revealed that urban gardening households (UGs) had older household heads who were less educated, and that land and water availability were the dominant constraints to increases in agricultural production. Results from the probit and average marginal effects models showed that the likelihood of participation significantly increased when household unemployment and dependency increased and that households who were engaged in off-farm economic activity were more likely to participate in urban gardening. The impact evaluation was performed using PSM and Average Treatment Effect on the Treated (ATT). Analysis illustrated that participation in urban gardening does significantly reduce both the full CSI and Reduced CSI. Thus, participation in urban gardening improves the food security of participating households by significantly reducing the frequency of participating households (UGs) applying undesirable coping strategies such as sending children elsewhere other than the household, borrowing food from other households and reducing the number of meals eaten in a day due to food shortages. This study posits that urban gardening alone will not eradicate the rampant food insecurity and poverty which pervades in South Africa’s townships. However, urban gardening participation does contribute to the construction of a sustainable, urban livelihood by reducing the number and severity of the undesirable coping strategies that food insecure households employ by providing some nutritious produce as well improved social capital through gardening networks and supporting institutions. It is recommended that policy makers, at a national and municipal level, need to create a clearer directive for the integration of urban food production into the urban food marketplace thus increasing access to income generating channels for small-scale home, and community gardeners. Co-operation between private and public institutions for food security and urban gardeners needs to be fostered and awareness of opportunities to participate in urban gardens needs to be improved. Central to the developmental challenges that rapid increases in urbanization and food insecurity in poor urban areas, is the need for national and local governments to improve access to economic opportunities in township areas - both in urban agriculture and in other, skills intensive sectors. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
The influence of financial socialisation agents on financial knowledge, financial self-efficacy and financial behaviour among South African consumers
- Authors: Maswena, Kaelo
- Date: 2022-04-06
- Subjects: Financial literacy South Africa , Finance, Personal South Africa , Budgets, Personal South Africa , Consumer behavior South Africa , Consumers Attitudes , Life skills South Africa , Social learning South Africa , Self-control South Africa , Socialization South Africa , Financial socialisation agents
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232421 , vital:49990
- Description: There is a need to promote positive financial behaviour in South Africa. According to the Human Sciences Research Council (2018), South African financial behaviour culture emphasises a financially vulnerable nation in terms of not having enough income for future planning and lacking financial self-control. In its key role in influencing financial behaviour, financial socialisation, which is characterised by interactions with indirect, or purposive financial education and communication of financial norms influencing financial behaviours, attitudes, knowledge, capabilities, and self-efficacy of consumers, is the topic of this study. The purpose of the study was to investigate the influence of financial socialisation agents on financial (actual and self-assessed) knowledge, financial self-efficacy and financial behaviour among South African consumers. Based on Glenn’s (2018) framework, Xiao et al. (2009) socialisation and Moschis et al. (1978) consumer socialisation theory, the financial socialisation theoretical framework is provided for this study. Literature review provided an overview of past studies on the concepts of financial socialisation, financial (actual and self-assessed) knowledge, financial self-efficacy and financial behaviour. Therefore, a positivistic research paradigm was adopted, which used a cross-sectional correlational research methodology. This study analysed data primarily collected by a questionnaire survey of South African social attitudes to financial literacy by the Human Sciences Research Council (2011), using a multi-staged sampling technique in all South African provinces of consumers of 16 years and older. Descriptive statistics showed that most respondents were black African females between the ages of 26 and 35 years. Most held Matric certificates and were in paid employment for 30 hours or more per week. Most respondents considered family to be the most influential financial socialisation agent, followed by friends, then the bank. Actual financial knowledge of respondents, was indicated as relatively high. Results on self-assessed financial knowledge showed that most of the respondents considered their level of financial knowledge to be neutral. Using Pearson product-moment correlations to measure the strength and correlations of relationships, positive significant correlations were found between financial socialisation agents, financial (actual and self-assessed) knowledge and financial self-efficacy, while a negative and insignificant correlation was found between financial socialisation agents and financial behaviour. Multiple regression analysis results testing the hypotheses of the study demonstrated that financial socialisation agents have a significant positive influence on financial (actual and self-assessed) knowledge and financial self-efficacy; a significant influence on financial behaviour was not reported. Self-assessed financial knowledge showed a positive significant influence on financial self-efficacy and actual financial knowledge had an insignificant negative influence on financial self-efficacy. Actual financial knowledge had a significant positive influence on financial behaviour, whereby a positive yet insignificant relationship was found between self-assessed knowledge and financial behaviour. In the end, recommendations for the results indicate that financial educators need to develop a financial education plan that will include other content areas of financial knowledge such as identified by Huston (2010) and Lusardi and Mitchell (2011); the most important recommendation would be to help consumers have an accurate understanding of their own level of financial knowledge and to improve financial self-efficacy in consumers, financial socialisation experiences such as offering encouragement to open a bank account, to save and invest money, and presenting opportunities to practise financial skills, may increase consumers’ self-efficacy and lead to positive financial behaviours. , Thesis (MCom) -- Faculty of Commerce, Management, 2022
- Full Text:
- Authors: Maswena, Kaelo
- Date: 2022-04-06
- Subjects: Financial literacy South Africa , Finance, Personal South Africa , Budgets, Personal South Africa , Consumer behavior South Africa , Consumers Attitudes , Life skills South Africa , Social learning South Africa , Self-control South Africa , Socialization South Africa , Financial socialisation agents
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232421 , vital:49990
- Description: There is a need to promote positive financial behaviour in South Africa. According to the Human Sciences Research Council (2018), South African financial behaviour culture emphasises a financially vulnerable nation in terms of not having enough income for future planning and lacking financial self-control. In its key role in influencing financial behaviour, financial socialisation, which is characterised by interactions with indirect, or purposive financial education and communication of financial norms influencing financial behaviours, attitudes, knowledge, capabilities, and self-efficacy of consumers, is the topic of this study. The purpose of the study was to investigate the influence of financial socialisation agents on financial (actual and self-assessed) knowledge, financial self-efficacy and financial behaviour among South African consumers. Based on Glenn’s (2018) framework, Xiao et al. (2009) socialisation and Moschis et al. (1978) consumer socialisation theory, the financial socialisation theoretical framework is provided for this study. Literature review provided an overview of past studies on the concepts of financial socialisation, financial (actual and self-assessed) knowledge, financial self-efficacy and financial behaviour. Therefore, a positivistic research paradigm was adopted, which used a cross-sectional correlational research methodology. This study analysed data primarily collected by a questionnaire survey of South African social attitudes to financial literacy by the Human Sciences Research Council (2011), using a multi-staged sampling technique in all South African provinces of consumers of 16 years and older. Descriptive statistics showed that most respondents were black African females between the ages of 26 and 35 years. Most held Matric certificates and were in paid employment for 30 hours or more per week. Most respondents considered family to be the most influential financial socialisation agent, followed by friends, then the bank. Actual financial knowledge of respondents, was indicated as relatively high. Results on self-assessed financial knowledge showed that most of the respondents considered their level of financial knowledge to be neutral. Using Pearson product-moment correlations to measure the strength and correlations of relationships, positive significant correlations were found between financial socialisation agents, financial (actual and self-assessed) knowledge and financial self-efficacy, while a negative and insignificant correlation was found between financial socialisation agents and financial behaviour. Multiple regression analysis results testing the hypotheses of the study demonstrated that financial socialisation agents have a significant positive influence on financial (actual and self-assessed) knowledge and financial self-efficacy; a significant influence on financial behaviour was not reported. Self-assessed financial knowledge showed a positive significant influence on financial self-efficacy and actual financial knowledge had an insignificant negative influence on financial self-efficacy. Actual financial knowledge had a significant positive influence on financial behaviour, whereby a positive yet insignificant relationship was found between self-assessed knowledge and financial behaviour. In the end, recommendations for the results indicate that financial educators need to develop a financial education plan that will include other content areas of financial knowledge such as identified by Huston (2010) and Lusardi and Mitchell (2011); the most important recommendation would be to help consumers have an accurate understanding of their own level of financial knowledge and to improve financial self-efficacy in consumers, financial socialisation experiences such as offering encouragement to open a bank account, to save and invest money, and presenting opportunities to practise financial skills, may increase consumers’ self-efficacy and lead to positive financial behaviours. , Thesis (MCom) -- Faculty of Commerce, Management, 2022
- Full Text:
The invasion autecology of Iris pseudacorus L. (Iridaceae) in South Africa
- Authors: Sandenbergh, Emma
- Date: 2022-04-06
- Subjects: Iris pseudacorus South Africa , Invasive plants South Africa , Aquatic weeds South Africa , Plant genetics South Africa , Freshwater ecology South Africa , Iris pseudacorus Geographical distribution , Phytogeography
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232272 , vital:49977
- Description: Iris pseudacorus L. (Iridaceae) is an emergent aquatic macrophyte originating from Europe, north Africa, and western Asia, and is becoming an increasingly problematic invader in South Africa. By forming dense rhizomatic mats in the absence of natural enemies, I. pseudacorus outcompetes co-occurring indigenous biota, causing serious environmental and socioeconomic challenges. Iris pseudacorus is a declared invader in South Africa, Argentina, New Zealand, the United States of America, and Canada, but little information is known regarding the species’ invasive potential, particularly in the southern hemisphere, hindering the effectiveness of control efforts. This study addresses this knowledge gap in a South African context, providing valuable insight into the invasion autecology of I. pseudacorus in South Africa. For effective management and control of I. pseudacorus in South Africa and the global south, its distribution and invasive potential must be determined, and its population genetics understood. Hence, this study aimed to map the current confirmed distribution of I. pseudacorus populations in South Africa, investigating the relative abundance of I. pseudacorus individuals in each population, and comparing their sexual reproductive outputs. Moreover, this study assessed the competitive interactions between I. pseudacorus and co-occurring native species T. capensis, and examined the genetic diversity present between and within South African I. pseudacorus populations. Through field surveys, I. pseudacorus infestations were confirmed in eight of the country’s nine provinces, with the highest number of infestations recorded in the urban hubs, and greatest population abundances reported in the warmer, wetter regions of South Africa. These surveys indicated that South African I. pseudacorus populations have enhanced their sexual reproductive output relative to native range populations, and a germination rate of ~ 83 % was determined in the laboratory. The results of a common garden competition experiment indicated that T. capensis may be a superior competitor over I. pseudacorus, but this was not supported by field observations, and may be a result of the short duration of the experiment. Using inter-simple sequence repeats (ISSRs), high genetic diversity was observed within and between populations of I. pseudacorus, indicating the employment of sexual reproductive strategies, and providing evidence for gene-flow between and within populations. Moreover, a weak negative correlation was observed between geographic distance and genetic similarity, ii indicating a largely anthropogenic spread of I. pseudacorus, and suggesting the occurrence of fewer founding events than reported in the United States. This study provides useful insight into the invasion autecology of I. pseudacorus in South Africa, contributing to the ongoing research surrounding I. pseudacorus invasions worldwide, particularly in the southern hemisphere. These results contribute to the development of appropriate adaptive and integrated management strategies to control I. pseudacorus invasions in South Africa, and should be implemented before South African I. pseudacorus infestations reach the severity observed elsewhere. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
- Authors: Sandenbergh, Emma
- Date: 2022-04-06
- Subjects: Iris pseudacorus South Africa , Invasive plants South Africa , Aquatic weeds South Africa , Plant genetics South Africa , Freshwater ecology South Africa , Iris pseudacorus Geographical distribution , Phytogeography
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232272 , vital:49977
- Description: Iris pseudacorus L. (Iridaceae) is an emergent aquatic macrophyte originating from Europe, north Africa, and western Asia, and is becoming an increasingly problematic invader in South Africa. By forming dense rhizomatic mats in the absence of natural enemies, I. pseudacorus outcompetes co-occurring indigenous biota, causing serious environmental and socioeconomic challenges. Iris pseudacorus is a declared invader in South Africa, Argentina, New Zealand, the United States of America, and Canada, but little information is known regarding the species’ invasive potential, particularly in the southern hemisphere, hindering the effectiveness of control efforts. This study addresses this knowledge gap in a South African context, providing valuable insight into the invasion autecology of I. pseudacorus in South Africa. For effective management and control of I. pseudacorus in South Africa and the global south, its distribution and invasive potential must be determined, and its population genetics understood. Hence, this study aimed to map the current confirmed distribution of I. pseudacorus populations in South Africa, investigating the relative abundance of I. pseudacorus individuals in each population, and comparing their sexual reproductive outputs. Moreover, this study assessed the competitive interactions between I. pseudacorus and co-occurring native species T. capensis, and examined the genetic diversity present between and within South African I. pseudacorus populations. Through field surveys, I. pseudacorus infestations were confirmed in eight of the country’s nine provinces, with the highest number of infestations recorded in the urban hubs, and greatest population abundances reported in the warmer, wetter regions of South Africa. These surveys indicated that South African I. pseudacorus populations have enhanced their sexual reproductive output relative to native range populations, and a germination rate of ~ 83 % was determined in the laboratory. The results of a common garden competition experiment indicated that T. capensis may be a superior competitor over I. pseudacorus, but this was not supported by field observations, and may be a result of the short duration of the experiment. Using inter-simple sequence repeats (ISSRs), high genetic diversity was observed within and between populations of I. pseudacorus, indicating the employment of sexual reproductive strategies, and providing evidence for gene-flow between and within populations. Moreover, a weak negative correlation was observed between geographic distance and genetic similarity, ii indicating a largely anthropogenic spread of I. pseudacorus, and suggesting the occurrence of fewer founding events than reported in the United States. This study provides useful insight into the invasion autecology of I. pseudacorus in South Africa, contributing to the ongoing research surrounding I. pseudacorus invasions worldwide, particularly in the southern hemisphere. These results contribute to the development of appropriate adaptive and integrated management strategies to control I. pseudacorus invasions in South Africa, and should be implemented before South African I. pseudacorus infestations reach the severity observed elsewhere. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
The quality of higher education and its influence on graduate employability and employer perception
- Authors: Mqingwana, Siviwe Nokulinda
- Date: 2022-04-06
- Subjects: Employability , Career education , Education, Higher Aims and objectives , College graduates Employment , Universities and colleges Ratings and rankings , Labor supply Effect of education on , College graduates Vocational guidance
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284526 , vital:56071
- Description: This study examined the quality of higher education and its influence on graduate employability and employer perception. Through determining the factors influencing graduates’ employment by employers and also the elements that induce employers in employing graduates, this was achieved. This research is rooted in a positivist perspective determining the relationship between graduate employability and a universities’ status. The main goal of this research was to examine to what extent employers are influenced by a higher education institution's perceived reputation when employing graduates. The linear regression model was used to predict the relationship between graduate employability (dependent variable) and the perceived reputation of the university by employers and citations of the university. This was achieved using quantitative methods. The quantitative database that this research relied on is Quacquarelli Symonds (QS) world university ranking. This research made use of descriptive data analysis as well as linear regression. The data set analysis showed citations of the institution had a significant negative relationship with the rate of employability (although this was a relatively weak relationship). The reputation of the institution and the number of international students enrolled do not affect the rate of employability. The analysed data set also showed that the number of citations of a university had a significant impact on the rate of employability at the 10% significance level. As such, higher education institutions need to consider including current market demand into their offerings to improve their graduate’s employability. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Authors: Mqingwana, Siviwe Nokulinda
- Date: 2022-04-06
- Subjects: Employability , Career education , Education, Higher Aims and objectives , College graduates Employment , Universities and colleges Ratings and rankings , Labor supply Effect of education on , College graduates Vocational guidance
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284526 , vital:56071
- Description: This study examined the quality of higher education and its influence on graduate employability and employer perception. Through determining the factors influencing graduates’ employment by employers and also the elements that induce employers in employing graduates, this was achieved. This research is rooted in a positivist perspective determining the relationship between graduate employability and a universities’ status. The main goal of this research was to examine to what extent employers are influenced by a higher education institution's perceived reputation when employing graduates. The linear regression model was used to predict the relationship between graduate employability (dependent variable) and the perceived reputation of the university by employers and citations of the university. This was achieved using quantitative methods. The quantitative database that this research relied on is Quacquarelli Symonds (QS) world university ranking. This research made use of descriptive data analysis as well as linear regression. The data set analysis showed citations of the institution had a significant negative relationship with the rate of employability (although this was a relatively weak relationship). The reputation of the institution and the number of international students enrolled do not affect the rate of employability. The analysed data set also showed that the number of citations of a university had a significant impact on the rate of employability at the 10% significance level. As such, higher education institutions need to consider including current market demand into their offerings to improve their graduate’s employability. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
The regulation of privacy on cloud computing services in terms of the Protection of Personal Information Act 4 of 2013
- Authors: Malahleka, Mthuthukisi
- Date: 2022-04-06
- Subjects: South Africa. Protection of Personal Information Act, 2013 , Cloud computing Law and legislation South Africa , Data protection Law and legislation South Africa , Personal information management South Africa , Data privacy South Africa , Computer security Law and legislation South Africa , General Data Protection Regulation (GDPR)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290731 , vital:56779
- Description: There is a relatively new development in Information Technology (IT) space known as cloud computing, software and service delivered remotely through the Internet without installing software on a computer. Cloud computing has quickly gathered steam as one of the most prominent topics in IT, and indeed within the business sector as a whole. Cloud computing is one such development associated with opportunities and benefits, especially in the commercial sector. Due to the development of IT and many businesses adopting e-commerce business-related strategies, cloud computing has revolutionised how personal information is processed. The advent of cloud computing as a mechanism to process personal information has brought many legal challenges for protecting the right to privacy enshrined under section 14 of the South African Constitution, which is a vulnerable part of one’s personality right. The right to privacy has long been protected even before adopting the Constitution under the common law of delict (actio iniuriarumn). As the adoption rate of cloud computing services by businesses continues to increase, the legal considerations and risks become more prevalent. The lawmakers struggle to keep pace with the rapidly changing technological advancements, at least for now. Both the common law and the Constitution could not address all the legal aspects of data protection and the adoption of cloud computing services hence the promulgation of the Protection of Personal Information Act 4 of 2013 (POPI Act). The POPI Act’s main objective is to protect the personal information of both natural and juristic persons. Personal information about an individual forms part of privacy. Unlawful processing of such personal information is a violation of the right to privacy of an individual. It is now widely recognised that the unregulated processing of personal information significantly impacts fundamental human rights like privacy, personality, and autonomy. A close analysis of cloud computing regulation is necessary, as legal protection mechanisms must safeguard the processing of personal information and establish extraterritorial jurisdiction to regulate the use of cloud computing within national legislation as cloud computing provides a transnational characteristic on the cross-border flow of personal information. In this thesis, a question is asked on whether the current data protection laws in South Africa on protecting the right to privacy in the cloud computing services context are adequate. The analysis will determine whether the overlaps between these pieces of data protection laws are competent to deal with the ever-increasing threats on the right to privacy and if they meet the international data protection standards set by the European Union’s General Data Protection Regulation (GDPR). The research seeks to analyse and reveal the shortcomings under the Constitution and the common law that led to adopting the POPI Act by studying the regulation of cloud computing services. This analysis will determine the shortcomings of the POPI Act as well in the context of cloud computing. The research will then follow a comparative analysis of the POPI Act and the GDPR to determine the application of the GDPR on international data breaches and compare its provisions with the POPI Act in the context of cloud computing. Finally, the research will address the question as to whether a multi-faceted approach, which includes a Model Law on cloud computing, would be an appropriate starting point setting out requirements for the use of this technology can be sufficient in protecting data subjects. And as cloud computing risks are not only a national but also a global problem, South Africa needs to look at the option of entering into mutual agreements with other countries and organisations to regulate cloud computing at an international level. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
- Authors: Malahleka, Mthuthukisi
- Date: 2022-04-06
- Subjects: South Africa. Protection of Personal Information Act, 2013 , Cloud computing Law and legislation South Africa , Data protection Law and legislation South Africa , Personal information management South Africa , Data privacy South Africa , Computer security Law and legislation South Africa , General Data Protection Regulation (GDPR)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290731 , vital:56779
- Description: There is a relatively new development in Information Technology (IT) space known as cloud computing, software and service delivered remotely through the Internet without installing software on a computer. Cloud computing has quickly gathered steam as one of the most prominent topics in IT, and indeed within the business sector as a whole. Cloud computing is one such development associated with opportunities and benefits, especially in the commercial sector. Due to the development of IT and many businesses adopting e-commerce business-related strategies, cloud computing has revolutionised how personal information is processed. The advent of cloud computing as a mechanism to process personal information has brought many legal challenges for protecting the right to privacy enshrined under section 14 of the South African Constitution, which is a vulnerable part of one’s personality right. The right to privacy has long been protected even before adopting the Constitution under the common law of delict (actio iniuriarumn). As the adoption rate of cloud computing services by businesses continues to increase, the legal considerations and risks become more prevalent. The lawmakers struggle to keep pace with the rapidly changing technological advancements, at least for now. Both the common law and the Constitution could not address all the legal aspects of data protection and the adoption of cloud computing services hence the promulgation of the Protection of Personal Information Act 4 of 2013 (POPI Act). The POPI Act’s main objective is to protect the personal information of both natural and juristic persons. Personal information about an individual forms part of privacy. Unlawful processing of such personal information is a violation of the right to privacy of an individual. It is now widely recognised that the unregulated processing of personal information significantly impacts fundamental human rights like privacy, personality, and autonomy. A close analysis of cloud computing regulation is necessary, as legal protection mechanisms must safeguard the processing of personal information and establish extraterritorial jurisdiction to regulate the use of cloud computing within national legislation as cloud computing provides a transnational characteristic on the cross-border flow of personal information. In this thesis, a question is asked on whether the current data protection laws in South Africa on protecting the right to privacy in the cloud computing services context are adequate. The analysis will determine whether the overlaps between these pieces of data protection laws are competent to deal with the ever-increasing threats on the right to privacy and if they meet the international data protection standards set by the European Union’s General Data Protection Regulation (GDPR). The research seeks to analyse and reveal the shortcomings under the Constitution and the common law that led to adopting the POPI Act by studying the regulation of cloud computing services. This analysis will determine the shortcomings of the POPI Act as well in the context of cloud computing. The research will then follow a comparative analysis of the POPI Act and the GDPR to determine the application of the GDPR on international data breaches and compare its provisions with the POPI Act in the context of cloud computing. Finally, the research will address the question as to whether a multi-faceted approach, which includes a Model Law on cloud computing, would be an appropriate starting point setting out requirements for the use of this technology can be sufficient in protecting data subjects. And as cloud computing risks are not only a national but also a global problem, South Africa needs to look at the option of entering into mutual agreements with other countries and organisations to regulate cloud computing at an international level. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
The role of a national system of innovation in facilitating development in South Africa from a comparative BRICS perspective
- Authors: Sibhukwana, Andiswa
- Date: 2022-04-06
- Subjects: BRIC countries , Technological innovations Economic aspects South Africa , Economic development South Africa , Economics Mathematical models , Neoclassical school of economics , South Africa Economic conditions , South Africa Economic policy , National systems of innovation
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284616 , vital:56079
- Description: The aim of the dissertation was to investigate whether the adoption of a national system of innovation has helped facilitate development in South Africa from a comparative BRICS perspective. South Africa has an expanding focus on science and technology, as per the Science and Technology White Paper (1996). There appeared to be innovation that had left out much of the citizenry. There continued to be poverty, inequality, and joblessness. The study aimed to understand how the NSI approach could be used to foster inclusive and transformative development. The study used a mixed-methods approach. The qualitative aspect of the research focused on an innovation and public policy study which assessed the various policies and initiatives implemented in each of the BRICS countries to drive innovation and foster development. The qualitative aspect of the study found that the innovation paradigm required governments to adopt a more holistic approach to public policy design and analysis. The quantitative aspect of the research focused on a trend, correlation, and regression analysis. The trend analysis revealed that China and Brazil increased their allocation of resources towards R&D compared to the other countries. Brazil is regarded as a social investment state, while China is a developmental state: this means the state plays an extraordinarily strong coordinative and financing role in the NSI. On the other hand, the correlation matrix for South Africa revealed a statistically significant positive linear association between various NSI indicators and human development. This suggested that the innovation benefits are trickling down to the general citizenry. In essence the study articulated key elements of the understanding of current and potential impacts of technological change in productivity and growth, employment and inequality that can be used for policy making. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Authors: Sibhukwana, Andiswa
- Date: 2022-04-06
- Subjects: BRIC countries , Technological innovations Economic aspects South Africa , Economic development South Africa , Economics Mathematical models , Neoclassical school of economics , South Africa Economic conditions , South Africa Economic policy , National systems of innovation
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284616 , vital:56079
- Description: The aim of the dissertation was to investigate whether the adoption of a national system of innovation has helped facilitate development in South Africa from a comparative BRICS perspective. South Africa has an expanding focus on science and technology, as per the Science and Technology White Paper (1996). There appeared to be innovation that had left out much of the citizenry. There continued to be poverty, inequality, and joblessness. The study aimed to understand how the NSI approach could be used to foster inclusive and transformative development. The study used a mixed-methods approach. The qualitative aspect of the research focused on an innovation and public policy study which assessed the various policies and initiatives implemented in each of the BRICS countries to drive innovation and foster development. The qualitative aspect of the study found that the innovation paradigm required governments to adopt a more holistic approach to public policy design and analysis. The quantitative aspect of the research focused on a trend, correlation, and regression analysis. The trend analysis revealed that China and Brazil increased their allocation of resources towards R&D compared to the other countries. Brazil is regarded as a social investment state, while China is a developmental state: this means the state plays an extraordinarily strong coordinative and financing role in the NSI. On the other hand, the correlation matrix for South Africa revealed a statistically significant positive linear association between various NSI indicators and human development. This suggested that the innovation benefits are trickling down to the general citizenry. In essence the study articulated key elements of the understanding of current and potential impacts of technological change in productivity and growth, employment and inequality that can be used for policy making. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
The use of the cochineal insect, Dactylopius tomentosus Lamarck, as a biological control agent for the invasive alien thistle cholla, Cylindropuntia pallida (Rose) F.M. Knuth in South Africa
- Authors: Zozo, Ekhona
- Date: 2022-04-06
- Subjects: Cochineal insect , Thistles Biological control South Africa , Alien plants South Africa , Invasive plants South Africa , Cactus South Africa , Biological assay
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/233823 , vital:50131
- Description: Cylindropuntia pallida (Rose) F.M. Knuth (Cactaceae) is an invasive alien plant in South Africa indigenous in the southern U.S.A. and Mexico. Large infestations of this species can be found in the Kalahari and arid Karoo regions of South Africa, which is also present in Namibia. Because it is a very spiny cactus, dense infestations have a negative impact on agriculture and natural ecosystems. This cactus has become naturalised to the extent that eradication is impossible and the negative impacts are steadily increasing due to its increasing distribution and density. The cochineal insect, Dactylopius tomentosus Lamarck (Dactylopiidae), is native in Mexico and parts of North America, such as Texas, Arizona, and New Mexico in the U.S.A. This cochineal species is highly specialized and associated only with Cylindropuntia species, a group of cacti that are primarily restricted to the same areas. It has been introduced into Australia and South Africa as a biological control agent to control various invasive alien Cylindropuntia species. This cochineal species has several biotypes specific to certain Cylindropuntia species hosts. A biotype is a clade that cannot be differentiated morphologically from others but has different host ranges and impacts depending on the host plant species. Included amongst biotypes that have been released in South Africa are D. tomentosus ‘imbricata’ and D. tomentosus ‘cholla’ for the biological control of Cylindropuntia imbricata (Haw.) F.M. Knuth (Cactaceae) and Cylindropuntia fulgida (Engelmann) F.M. Knuth var. mamillata (Schott ex Engelmann) Backeb. (Cactaceae), respectively. These biotypes have resulted in both host plants being under substantial control in South Africa. The first part of this thesis evaluated which of the two D. tomentosus biotypes already in use in South Africa could be an effective biological control agent for C. pallida. This was done by assessing the fitness of the cochineals on the three cactus species and assessing the impact that each of the cochineals has on each of the target weed species. Should these biotypes prove ineffective, there is a third biotype, namely D. tomentosus ‘californica var. parkerii’, which researchers in Australia have worked on and have found to be suitably host-specific for release in Australia and suitably damaging to C. pallida in that country. Therefore, this new biotype could be released in South Africa if it is required. Sexually compatible biological control agents, especially those closely related and occurring in close spatial proximity to one another, may interbreed and the impacts of this hybridisation are difficult to predict. It is important to understand the outcomes of the hybridisation of cochineal because it can affect the impact of the biological control agents and thus the control of the target weed. The second part of this thesis investigated the impacts of the hybridisation of the two cochineal biotypes by assessing the damage the agents would have on the target weed, and on C. imbricata and C. fulgida var. mamillata, in the presence of one or both cochineal biotypes. The ‘cholla’ biotype performed better on C. pallida than the ‘imbricata’ biotype, but neither biotype could control C. pallida to an extent similar to the control they provide for their respective target weeds, C. imbricata and C. fulgida var. mamillata. Both the ‘cholla’ biotype and hybrids of the two biotypes of cochineal were effective at killing C. pallida when both C. imbricata and C. fulgida var. mamillata were also present. This suggests that the ‘cholla’ or hybrids may be effective at controlling C. pallida when either C. imbricata or C. fulgida var. mamillata are also present in the field due to the high population density of cochineal that results under these circumstances. There are, however, many C. pallida infestations in South Africa where the plant is problematic and is isolated from other Cylindropuntia species, and these populations are unlikely to be controlled by the ‘cholla’ biotype or the hybrids. Neither of the cochineal biotypes that are used for biological control in South Africa are suitably damaging to C. pallida to warrant their use as biological control agents for this species. Dactylopius tomentosus ‘californica var. parkerii’ is therefore recommended for release based on its host-specificity and impact to C. pallida in Australia. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Authors: Zozo, Ekhona
- Date: 2022-04-06
- Subjects: Cochineal insect , Thistles Biological control South Africa , Alien plants South Africa , Invasive plants South Africa , Cactus South Africa , Biological assay
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/233823 , vital:50131
- Description: Cylindropuntia pallida (Rose) F.M. Knuth (Cactaceae) is an invasive alien plant in South Africa indigenous in the southern U.S.A. and Mexico. Large infestations of this species can be found in the Kalahari and arid Karoo regions of South Africa, which is also present in Namibia. Because it is a very spiny cactus, dense infestations have a negative impact on agriculture and natural ecosystems. This cactus has become naturalised to the extent that eradication is impossible and the negative impacts are steadily increasing due to its increasing distribution and density. The cochineal insect, Dactylopius tomentosus Lamarck (Dactylopiidae), is native in Mexico and parts of North America, such as Texas, Arizona, and New Mexico in the U.S.A. This cochineal species is highly specialized and associated only with Cylindropuntia species, a group of cacti that are primarily restricted to the same areas. It has been introduced into Australia and South Africa as a biological control agent to control various invasive alien Cylindropuntia species. This cochineal species has several biotypes specific to certain Cylindropuntia species hosts. A biotype is a clade that cannot be differentiated morphologically from others but has different host ranges and impacts depending on the host plant species. Included amongst biotypes that have been released in South Africa are D. tomentosus ‘imbricata’ and D. tomentosus ‘cholla’ for the biological control of Cylindropuntia imbricata (Haw.) F.M. Knuth (Cactaceae) and Cylindropuntia fulgida (Engelmann) F.M. Knuth var. mamillata (Schott ex Engelmann) Backeb. (Cactaceae), respectively. These biotypes have resulted in both host plants being under substantial control in South Africa. The first part of this thesis evaluated which of the two D. tomentosus biotypes already in use in South Africa could be an effective biological control agent for C. pallida. This was done by assessing the fitness of the cochineals on the three cactus species and assessing the impact that each of the cochineals has on each of the target weed species. Should these biotypes prove ineffective, there is a third biotype, namely D. tomentosus ‘californica var. parkerii’, which researchers in Australia have worked on and have found to be suitably host-specific for release in Australia and suitably damaging to C. pallida in that country. Therefore, this new biotype could be released in South Africa if it is required. Sexually compatible biological control agents, especially those closely related and occurring in close spatial proximity to one another, may interbreed and the impacts of this hybridisation are difficult to predict. It is important to understand the outcomes of the hybridisation of cochineal because it can affect the impact of the biological control agents and thus the control of the target weed. The second part of this thesis investigated the impacts of the hybridisation of the two cochineal biotypes by assessing the damage the agents would have on the target weed, and on C. imbricata and C. fulgida var. mamillata, in the presence of one or both cochineal biotypes. The ‘cholla’ biotype performed better on C. pallida than the ‘imbricata’ biotype, but neither biotype could control C. pallida to an extent similar to the control they provide for their respective target weeds, C. imbricata and C. fulgida var. mamillata. Both the ‘cholla’ biotype and hybrids of the two biotypes of cochineal were effective at killing C. pallida when both C. imbricata and C. fulgida var. mamillata were also present. This suggests that the ‘cholla’ or hybrids may be effective at controlling C. pallida when either C. imbricata or C. fulgida var. mamillata are also present in the field due to the high population density of cochineal that results under these circumstances. There are, however, many C. pallida infestations in South Africa where the plant is problematic and is isolated from other Cylindropuntia species, and these populations are unlikely to be controlled by the ‘cholla’ biotype or the hybrids. Neither of the cochineal biotypes that are used for biological control in South Africa are suitably damaging to C. pallida to warrant their use as biological control agents for this species. Dactylopius tomentosus ‘californica var. parkerii’ is therefore recommended for release based on its host-specificity and impact to C. pallida in Australia. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
Thicket expansion in a vachellia karroo-dominated landscape and its effect on herbaceous communities
- Authors: Khoza, Marina Rindzani
- Date: 2022-04-06
- Subjects: Savanna ecology South Africa , Forbs South Africa , Grasslands South Africa , Herbaceous plants South Africa , Vegetation dynamics South Africa , Forest canopies South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291015 , vital:56808
- Description: Grass and forb species found in savannas are highly diverse, contributing to the structure and function of the savanna system. Where mean annual rainfall is seasonal and high enough to support closed canopy vegetation such as forests or thickets, savannas can exist as an alternative stable state maintained by disturbances such as fire and browsing. Biotic and abiotic processes act on savanna and forest (or thicket) systems maintaining both their tree and herbaceous cover at levels that ensure their persistence in those states. Studies have shown that many semi-arid rangelands in South Africa have undergone a rapid increase in tree cover (of both native and non-native species) over the past several decades. This process of increasing tree cover in semi-arid savannas, termed bush encroachment, results in a biome shift, changing landscapes that were once grasslands with few trees to ones dominated by broad-leaved trees with fewer sun-adapted forbs and grasses. The aim of this study was to investigate the impact of changing woody cover and its associated changes in tree composition, tree canopy structure, light dynamics in the understory and herbaceous community composition on Endwell farm in the Eastern Cape. Canopy cover changes between the years 1949 and 2019 were analysed at 51 sites on the farm and related to historical rainfall patterns. There had been a general increase in tree cover over the past several decades on the farm, and many sites showed a change from open (0-15%) in 1949 to low (1635%), moderate (36-50%) and high (51-100%) canopy cover in 2019. In earlier years most sites had a canopy cover below 50%, and the higher canopy cover values (>65%) occurred in more recent decades. Canopy cover of ~ 50% was found to be rare in each decade. This suggests that ~50% canopy cover maybe a transient, unstable state. The period with the highest rate of canopy cover increase was 2002-2013, and this increase coincided with a high mean annual rainfall 10 years prior to 2002 and a high mean annual rainfall in most years between the 20022013 period. The period between 2002 and 2013 also had the highest number of sites transitioning from lower to higher tree canopy cover classes, indicating that rainfall may have been a factor driving bush encroachment during the past several decades. An increase in canopy cover (a decrease in light transmittance) was accompanied by changes in woody species composition during thicket formation. The low canopy cover (high light transmittance) sites were dominated by Vachellia karroo and Scutia myrtina trees, while high tree cover sites had fewer V. karroo and S. myrtina trees and were rather characterised by an abundance of thicket tree species. Species proportion, NMDS and dendrogram plots indicated that sites with a light transmittance range between 50-100% had similar tree species compositions, different from sites with light transmittances <50%. An increase in tree density was strongly correlated to an increase in canopy cover (from 2019 satellite imagery), density of trees > 3m, maximum height reached by trees, diversity of trees, total canopy volume, total canopy area and leaf area index (LAI), and a decrease in light transmittance. A structural equation model (SEM) was used to explore the relationships between canopy characteristics (maximum canopy area, canopy volume, tree diversity, density of trees, density of trees >3m, individual trees and maximum canopy height), aerial canopy cover in 2019, and light transmittance. The model explained 73% of the variation in light transmittance, mostly via the direct effect of canopy characteristics. Canopy characteristics had a strong influence on both aerial cover in 2019 and directly on light transmittance, but canopy cover in 2019 had a weak influence on light transmittance. The herbaceous layer was rich and dominated by C4 grasses such as Eragrostis plana, Sporobolus fimbriatus, Themeda triandra and Digitaria eriantha) and forbs including Hibiscus aethiopicus, Helichrysum dregeanum, Helichrysum nudifolium and Gerbera viridifolia at low canopy cover sites with high light transmittance. In contrast, high tree cover sites had fewer herbaceous species in general. Grass and forb species characteristic of these sites high canopy cover sites were Panicum maximum, Loudetia flavida, Pellaea viridis and Cyperus spp. Different sites with low light transmittance (<50%) had similar herbaceous species composition. Basal cover, richness, abundance and diversity of herbaceous plants decreased significantly with an increase in tree density, density of trees >3 m, canopy volume, canopy area, canopy cover, LAI, and increased significantly with increasing light transmittance. Most grasses had their highest densities at LAI <0.5, which was estimated to correspond to ~75% light transmittance and ~38% canopy cover and then started to decline thereafter. Herbaceous species basal cover was also highest at LAI <0.5. An SEM model indicated that herbaceous diversity, basal cover and richness responded both to light availability and to the structure of the woody vegetation directly (R2 = 0.53). While the effect of light transmittance on herbaceous communities was strong (0.41), there was little difference between the effect of light transmittance and canopy characteristics (-0.35) on herbaceous communities. Two possible threshold points, relating to two types of transitions in vegetation structure, could be deduced from this study. The first threshold occurred at canopy cover ~ 40% (LAI < ~ 0.5, light transmittance ~ 75%), at which point many of the common herbaceous species, including the dominant C4 grasses, began to decline in abundance while the composition remained characteristic of the savanna state. A canopy cover of less than ~ 40% at a site provides a suitable state for a high abundance of grass and forb species which help maintain an open system by facilitating fires. The second threshold marked a compositional shift between savanna and closed-canopy vegetation states. Savanna species (trees, grasses and forbs) dominated at high light transmittances (>50%) and were significantly reduced at low light transmittances (< 50%), indicating a possible species composition threshold at ~50% light transmittance at which a savanna state switches to a thicket (LAI ~ 1 and canopy cover ~70%). This point indicated the point where there was a significant difference in both tree and herbaceous plant compositions, with a marked reduction in the occurrence of C4 grasses at light transmittance <50%. Fire is supressed when the C4 grass layer is lost, and further thicket encroachment will take place causing complete canopy closure. Land managers in this system should start becoming concerned about a reduction in grass biomass when canopy cover reaches about 40% and would have to reduce tree cover before the threshold of 50% light transmittance (70% canopy cover from aerial photos) is reached to maintain a savanna system. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
Thicket expansion in a vachellia karroo-dominated landscape and its effect on herbaceous communities
- Authors: Khoza, Marina Rindzani
- Date: 2022-04-06
- Subjects: Savanna ecology South Africa , Forbs South Africa , Grasslands South Africa , Herbaceous plants South Africa , Vegetation dynamics South Africa , Forest canopies South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291015 , vital:56808
- Description: Grass and forb species found in savannas are highly diverse, contributing to the structure and function of the savanna system. Where mean annual rainfall is seasonal and high enough to support closed canopy vegetation such as forests or thickets, savannas can exist as an alternative stable state maintained by disturbances such as fire and browsing. Biotic and abiotic processes act on savanna and forest (or thicket) systems maintaining both their tree and herbaceous cover at levels that ensure their persistence in those states. Studies have shown that many semi-arid rangelands in South Africa have undergone a rapid increase in tree cover (of both native and non-native species) over the past several decades. This process of increasing tree cover in semi-arid savannas, termed bush encroachment, results in a biome shift, changing landscapes that were once grasslands with few trees to ones dominated by broad-leaved trees with fewer sun-adapted forbs and grasses. The aim of this study was to investigate the impact of changing woody cover and its associated changes in tree composition, tree canopy structure, light dynamics in the understory and herbaceous community composition on Endwell farm in the Eastern Cape. Canopy cover changes between the years 1949 and 2019 were analysed at 51 sites on the farm and related to historical rainfall patterns. There had been a general increase in tree cover over the past several decades on the farm, and many sites showed a change from open (0-15%) in 1949 to low (1635%), moderate (36-50%) and high (51-100%) canopy cover in 2019. In earlier years most sites had a canopy cover below 50%, and the higher canopy cover values (>65%) occurred in more recent decades. Canopy cover of ~ 50% was found to be rare in each decade. This suggests that ~50% canopy cover maybe a transient, unstable state. The period with the highest rate of canopy cover increase was 2002-2013, and this increase coincided with a high mean annual rainfall 10 years prior to 2002 and a high mean annual rainfall in most years between the 20022013 period. The period between 2002 and 2013 also had the highest number of sites transitioning from lower to higher tree canopy cover classes, indicating that rainfall may have been a factor driving bush encroachment during the past several decades. An increase in canopy cover (a decrease in light transmittance) was accompanied by changes in woody species composition during thicket formation. The low canopy cover (high light transmittance) sites were dominated by Vachellia karroo and Scutia myrtina trees, while high tree cover sites had fewer V. karroo and S. myrtina trees and were rather characterised by an abundance of thicket tree species. Species proportion, NMDS and dendrogram plots indicated that sites with a light transmittance range between 50-100% had similar tree species compositions, different from sites with light transmittances <50%. An increase in tree density was strongly correlated to an increase in canopy cover (from 2019 satellite imagery), density of trees > 3m, maximum height reached by trees, diversity of trees, total canopy volume, total canopy area and leaf area index (LAI), and a decrease in light transmittance. A structural equation model (SEM) was used to explore the relationships between canopy characteristics (maximum canopy area, canopy volume, tree diversity, density of trees, density of trees >3m, individual trees and maximum canopy height), aerial canopy cover in 2019, and light transmittance. The model explained 73% of the variation in light transmittance, mostly via the direct effect of canopy characteristics. Canopy characteristics had a strong influence on both aerial cover in 2019 and directly on light transmittance, but canopy cover in 2019 had a weak influence on light transmittance. The herbaceous layer was rich and dominated by C4 grasses such as Eragrostis plana, Sporobolus fimbriatus, Themeda triandra and Digitaria eriantha) and forbs including Hibiscus aethiopicus, Helichrysum dregeanum, Helichrysum nudifolium and Gerbera viridifolia at low canopy cover sites with high light transmittance. In contrast, high tree cover sites had fewer herbaceous species in general. Grass and forb species characteristic of these sites high canopy cover sites were Panicum maximum, Loudetia flavida, Pellaea viridis and Cyperus spp. Different sites with low light transmittance (<50%) had similar herbaceous species composition. Basal cover, richness, abundance and diversity of herbaceous plants decreased significantly with an increase in tree density, density of trees >3 m, canopy volume, canopy area, canopy cover, LAI, and increased significantly with increasing light transmittance. Most grasses had their highest densities at LAI <0.5, which was estimated to correspond to ~75% light transmittance and ~38% canopy cover and then started to decline thereafter. Herbaceous species basal cover was also highest at LAI <0.5. An SEM model indicated that herbaceous diversity, basal cover and richness responded both to light availability and to the structure of the woody vegetation directly (R2 = 0.53). While the effect of light transmittance on herbaceous communities was strong (0.41), there was little difference between the effect of light transmittance and canopy characteristics (-0.35) on herbaceous communities. Two possible threshold points, relating to two types of transitions in vegetation structure, could be deduced from this study. The first threshold occurred at canopy cover ~ 40% (LAI < ~ 0.5, light transmittance ~ 75%), at which point many of the common herbaceous species, including the dominant C4 grasses, began to decline in abundance while the composition remained characteristic of the savanna state. A canopy cover of less than ~ 40% at a site provides a suitable state for a high abundance of grass and forb species which help maintain an open system by facilitating fires. The second threshold marked a compositional shift between savanna and closed-canopy vegetation states. Savanna species (trees, grasses and forbs) dominated at high light transmittances (>50%) and were significantly reduced at low light transmittances (< 50%), indicating a possible species composition threshold at ~50% light transmittance at which a savanna state switches to a thicket (LAI ~ 1 and canopy cover ~70%). This point indicated the point where there was a significant difference in both tree and herbaceous plant compositions, with a marked reduction in the occurrence of C4 grasses at light transmittance <50%. Fire is supressed when the C4 grass layer is lost, and further thicket encroachment will take place causing complete canopy closure. Land managers in this system should start becoming concerned about a reduction in grass biomass when canopy cover reaches about 40% and would have to reduce tree cover before the threshold of 50% light transmittance (70% canopy cover from aerial photos) is reached to maintain a savanna system. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
Trace element and sulphur isotope variations of sulphides in the Koperberg Suite, O’okiep Copper District, Namaqualand, South Africa: implications for formation of sulphides and the role of crustal sulphur assimilation
- Authors: Marima, Edmore
- Date: 2022-04-06
- Subjects: Sulfur Isotopes , Magmatism South Africa Namaqualand , Sulfides , Koperberg Suite (South Africa) , Copper sulfide , Sulfur Absorption and adsorption
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291117 , vital:56820
- Description: The major economic copper sulphide deposits hosted in the late Mesoproterozoic intrusions of the Koperberg Suite in the O’okiep Copper District immediately overlie sulphur-bearing paragneisses of the Khurisberg Subgroup in an otherwise low-sulphur granitic basement. The dominant sulphide assemblage (chalcopyrite and bornite) hosted in the Koperberg Suite is also atypical of the intermediate solid solution (iss) assemblage (chalcopyrite and pyrrhotite) observed in most Cu-Ni magmatic sulphide deposits. This study presents sulphur isotope and in-situ trace element analysis of sulphides from the Koperberg Suite and the Khurisberg Subgroup with the view of placing constraints on the role of sulphide-bearing supracrustal metasedimentary of the Khurisberg Subgroup as a source of additional sulphur in the genesis of these deposits, and ore-forming (sulphide formation) processes which result in trace element variations registered by sulphides hosted in the Koperberg Suite. The high concentrations (up to 2100 ppm) of monosulphide solid solution (mss)-incompatible trace elements (e.g., Te, Se, Bi, Ag, Pb), and the depletion in Ni and Co (<40 ppm) of sulphides hosted in the Koperberg Suite are instead consistent with the derivation of such sulphides from a Cu-rich sulphide melt which segregated from a Ni-rich sulphide melt prior to magma emplacement in the middle crust, in agreement with one of the petrogenetic models for the Koperberg Suite proposed in the existing literature. The low S/Se ratios ( ̴650-10300) of sulphides hosted in the Koperberg Suite and the high S/Se ratios ( ̴18800-56000) registered by the main sulphide phase (pyrite) in the Khurisberg Subgroup argues against crustal contamination of the Koperberg Suite magmas by the Khurisberg Subgroup. The S/Se and Cu/S ratios of coexisting bornite and chalcopyrite hosted in the Koperberg Suite are positively correlated with the bornite modal abundance in the Koperberg Suite. Such trends are interpreted to be consistent with progressive oxidation of sulphide melt, a process which results in the crystallisation of iss-bornite assemblage and/or replacement of iss with bornite due to the enrichment of Cu and depletion in S of the sulphide melt. The oxidation of sulphide melt is likely to have been effectuated by the fractional crystallisation of mss in a prior sulphide melt segregation event and/or the fractional crystallisation of Fe2+-dominated silicate phases. Fractionation of the Cu-rich melt sulphide melt (segregated from mss) also tends to enrich the residual sulphide melts in Se. Thus, the chalcopyrite-dominated assemblage with S/Se ratios of ̴1300-10200 observed in the less basic rocks in the Koperberg Suite (leucodiorites and leuconorites) is interpreted to have formed from the least evolved sulphide melt, whereas the bornite-dominated assemblage with S/Se ratios of ̴650-5500 observed in the more mafic members of the Koperberg Suite (orthopyroxenites and norites) is interpreted to have formed from the most evolved sulphide melt. The ẟ34S isotopic signatures in sulphides of the Koperberg Suite (-1.4 to +1.91‰) and the proposed contaminant, the Khurisberg Subgroup (-1.2 to +3.5‰), overlap with the those of the Koperberg Suite below the Khurisberg Subgroup (+0.74‰) and typical mantle-derived magmatic rocks (0 ± iv 2‰). Hence, the sulphur isotope variations are inconclusive as an indicator of possible crustal sulphur assimilation into the intruding mantle magma. However, considering the trace element systematics and the sulphur isotope data, the Koperberg magmas likely attained sulphur saturation at deeper crustal levels. , Thesis (MSc) -- Faculty of Science, Geology, 2022
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- Authors: Marima, Edmore
- Date: 2022-04-06
- Subjects: Sulfur Isotopes , Magmatism South Africa Namaqualand , Sulfides , Koperberg Suite (South Africa) , Copper sulfide , Sulfur Absorption and adsorption
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291117 , vital:56820
- Description: The major economic copper sulphide deposits hosted in the late Mesoproterozoic intrusions of the Koperberg Suite in the O’okiep Copper District immediately overlie sulphur-bearing paragneisses of the Khurisberg Subgroup in an otherwise low-sulphur granitic basement. The dominant sulphide assemblage (chalcopyrite and bornite) hosted in the Koperberg Suite is also atypical of the intermediate solid solution (iss) assemblage (chalcopyrite and pyrrhotite) observed in most Cu-Ni magmatic sulphide deposits. This study presents sulphur isotope and in-situ trace element analysis of sulphides from the Koperberg Suite and the Khurisberg Subgroup with the view of placing constraints on the role of sulphide-bearing supracrustal metasedimentary of the Khurisberg Subgroup as a source of additional sulphur in the genesis of these deposits, and ore-forming (sulphide formation) processes which result in trace element variations registered by sulphides hosted in the Koperberg Suite. The high concentrations (up to 2100 ppm) of monosulphide solid solution (mss)-incompatible trace elements (e.g., Te, Se, Bi, Ag, Pb), and the depletion in Ni and Co (<40 ppm) of sulphides hosted in the Koperberg Suite are instead consistent with the derivation of such sulphides from a Cu-rich sulphide melt which segregated from a Ni-rich sulphide melt prior to magma emplacement in the middle crust, in agreement with one of the petrogenetic models for the Koperberg Suite proposed in the existing literature. The low S/Se ratios ( ̴650-10300) of sulphides hosted in the Koperberg Suite and the high S/Se ratios ( ̴18800-56000) registered by the main sulphide phase (pyrite) in the Khurisberg Subgroup argues against crustal contamination of the Koperberg Suite magmas by the Khurisberg Subgroup. The S/Se and Cu/S ratios of coexisting bornite and chalcopyrite hosted in the Koperberg Suite are positively correlated with the bornite modal abundance in the Koperberg Suite. Such trends are interpreted to be consistent with progressive oxidation of sulphide melt, a process which results in the crystallisation of iss-bornite assemblage and/or replacement of iss with bornite due to the enrichment of Cu and depletion in S of the sulphide melt. The oxidation of sulphide melt is likely to have been effectuated by the fractional crystallisation of mss in a prior sulphide melt segregation event and/or the fractional crystallisation of Fe2+-dominated silicate phases. Fractionation of the Cu-rich melt sulphide melt (segregated from mss) also tends to enrich the residual sulphide melts in Se. Thus, the chalcopyrite-dominated assemblage with S/Se ratios of ̴1300-10200 observed in the less basic rocks in the Koperberg Suite (leucodiorites and leuconorites) is interpreted to have formed from the least evolved sulphide melt, whereas the bornite-dominated assemblage with S/Se ratios of ̴650-5500 observed in the more mafic members of the Koperberg Suite (orthopyroxenites and norites) is interpreted to have formed from the most evolved sulphide melt. The ẟ34S isotopic signatures in sulphides of the Koperberg Suite (-1.4 to +1.91‰) and the proposed contaminant, the Khurisberg Subgroup (-1.2 to +3.5‰), overlap with the those of the Koperberg Suite below the Khurisberg Subgroup (+0.74‰) and typical mantle-derived magmatic rocks (0 ± iv 2‰). Hence, the sulphur isotope variations are inconclusive as an indicator of possible crustal sulphur assimilation into the intruding mantle magma. However, considering the trace element systematics and the sulphur isotope data, the Koperberg magmas likely attained sulphur saturation at deeper crustal levels. , Thesis (MSc) -- Faculty of Science, Geology, 2022
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Transfer pricing: an analysis of legislation in the southern African Customs Union
- Authors: Patel, Nabil Ahmed
- Date: 2022-04-06
- Subjects: Transfer pricing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/241482 , vital:50943
- Description: Transfer pricing is defined as the setting of the price for goods sold and services rendered between related entities. For example, if a subsidiary company sells goods or renders services to its holding company or a sister company, the price charged is referred to as the transfer price. Transfer pricing can be used to manipulate profits and facilitate tax evasion. Therefore, it is important that countries enact transfer pricing legislation to prevent this. The United Nations (UN) and Organisation for Economic Co-operation and Development (OECD) guideline documents form the basis for most global legislation and conventions dealing with transfer pricing. The over-arching goal of this research was to investigate whether transfer pricing legislation in the Southern African Customs Union (SACU) aligns between SACU countries and with the OECD Guidelines and the UN Manual. The research applied a legal interpretive doctrinal research methodology and a qualitative research method. The data comprised primary legislation in the SACU countries, transfer pricing guidelines issued by revenue authorities in the SACU, OECD Guidelines, the UN Manual and journal articles. It was found in this study that certain aspects of transfer pricing legislation in the SACU are not fully aligned to each other and to the OECD Guidelines and the UN Manual. This study proposed recommendations to improve transfer pricing legislation in the SACU. These improvements include the introduction of transfer pricing legislation in Eswatini and Lesotho, and updating transfer pricing legislation in Namibia and South Africa in terms of the latest versions of the OECD Guidelines and the UN Manual. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
- Full Text:
- Authors: Patel, Nabil Ahmed
- Date: 2022-04-06
- Subjects: Transfer pricing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/241482 , vital:50943
- Description: Transfer pricing is defined as the setting of the price for goods sold and services rendered between related entities. For example, if a subsidiary company sells goods or renders services to its holding company or a sister company, the price charged is referred to as the transfer price. Transfer pricing can be used to manipulate profits and facilitate tax evasion. Therefore, it is important that countries enact transfer pricing legislation to prevent this. The United Nations (UN) and Organisation for Economic Co-operation and Development (OECD) guideline documents form the basis for most global legislation and conventions dealing with transfer pricing. The over-arching goal of this research was to investigate whether transfer pricing legislation in the Southern African Customs Union (SACU) aligns between SACU countries and with the OECD Guidelines and the UN Manual. The research applied a legal interpretive doctrinal research methodology and a qualitative research method. The data comprised primary legislation in the SACU countries, transfer pricing guidelines issued by revenue authorities in the SACU, OECD Guidelines, the UN Manual and journal articles. It was found in this study that certain aspects of transfer pricing legislation in the SACU are not fully aligned to each other and to the OECD Guidelines and the UN Manual. This study proposed recommendations to improve transfer pricing legislation in the SACU. These improvements include the introduction of transfer pricing legislation in Eswatini and Lesotho, and updating transfer pricing legislation in Namibia and South Africa in terms of the latest versions of the OECD Guidelines and the UN Manual. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
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Wild Honeybush (Cyclopia intermedia) augmentation
- Authors: Michau, Paul-Luc
- Date: 2022-04-06
- Subjects: Herbal teas South Africa Joubertina , Tea trade South Africa Joubertina , Legumes Harvesting South Africa Joubertina , Legumes Planting South Africa Joubertina , Sustainable development South Africa Joubertina , Economic development Environmental aspects South Africa Joubertina , Natural resources Management South Africa Joubertina , Wild Honeybush (Cyclopia intermedia)
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232635 , vital:50009
- Description: Honeybush (Cyclopia spp.) is an endemic legume to the fynbos region of South Africa, and certain species of the genus are used to make health tonics. There are growing international markets for such products and, currently, wild populations of the species Cyclopia intermedia are disproportionately relied upon to support this increase. Due to the sensitivity and ecological complexity of the resource, serious concerns about sustainability and regulation have arisen. The social landscape of the resource is equally as complex, and solutions for alleviating pressure on wild populations, such as reducing or banning harvesting, and switching to commercial cultivation are untenable in every case. A possible option, which has been used in the wildflower industry, is to augment (increase) wild populations by planting seeds or seedlings directly into the veld. The main focus of this research was to explore the viability of using augmentation to boost wild populations of C. intermedia through field trials. In support of this broad aim, research objectives addressed understanding the ecological habitat conditions of the species, quantifying the economic potential of augmentation, characterizing wild populations and conducting seed germination tests. GIS methods were used to locate sites most representative of natural conditions on different post-fire aged veld on a farm in the Kouga mountains. The study characterized habitat conditions by collecting soil and vegetation samples at plots where honeybush was present and absent within close proximity. Vegetation diversity was only slightly higher in presence plots, and no clear pattern between absence and presence plots was observed for soil properties. However, post-fire site age did significantly influence certain nutrient levels. The augmentation trial results indicate that seedlings have a much higher survival rate than seeds on average. Survival success varied unpredictably between plots where wild honeybush was already present and adjacent plots where it was absent. Post-fire site age influenced seedling growth and seed survival positively with the newly burnt plots showing the best growth rates overall. The cost-benefit analysis reveals that seeds are a better option as they require low-cost inputs and carry less risk, unlike seedlings which may have higher survival but are more expensive. The study recommends using trials to assess survival before choosing an option. Out of five natural populations of honeybush that were assessed only one showed seedling recruitment and three young plants were found between two of the other sites. Growth characteristics of populations showed expected variability based on site conditions and disturbance history. Growth appears to be rapid in the first-year post disturbance, thereafter slowing down. Average stem numbers and basal circumference increased concurrently for both harvested and unharvested populations. Due to the influence of natural conditions such as slope aspect and soil properties on plant morphology, it is best to compare harvested and unharvested individuals from the same site and preferably within close proximity to minimize such differences. Using seed sourced from the same parent population is critical to preserving genetic integrity and little is understood about germination characteristics from wild C. intermedia populations. The study tested germination rates between green and brown seed and alternative collection methods. When comparisons were done within farms on two occasions collection and seed colour did have a significant influence. Overall, the influence of which farm the seeds were collected from appeared to play the biggest role in determining germination. , Thesis (MSc) -- Faculty of Science, Geography, 2022
- Full Text:
- Authors: Michau, Paul-Luc
- Date: 2022-04-06
- Subjects: Herbal teas South Africa Joubertina , Tea trade South Africa Joubertina , Legumes Harvesting South Africa Joubertina , Legumes Planting South Africa Joubertina , Sustainable development South Africa Joubertina , Economic development Environmental aspects South Africa Joubertina , Natural resources Management South Africa Joubertina , Wild Honeybush (Cyclopia intermedia)
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232635 , vital:50009
- Description: Honeybush (Cyclopia spp.) is an endemic legume to the fynbos region of South Africa, and certain species of the genus are used to make health tonics. There are growing international markets for such products and, currently, wild populations of the species Cyclopia intermedia are disproportionately relied upon to support this increase. Due to the sensitivity and ecological complexity of the resource, serious concerns about sustainability and regulation have arisen. The social landscape of the resource is equally as complex, and solutions for alleviating pressure on wild populations, such as reducing or banning harvesting, and switching to commercial cultivation are untenable in every case. A possible option, which has been used in the wildflower industry, is to augment (increase) wild populations by planting seeds or seedlings directly into the veld. The main focus of this research was to explore the viability of using augmentation to boost wild populations of C. intermedia through field trials. In support of this broad aim, research objectives addressed understanding the ecological habitat conditions of the species, quantifying the economic potential of augmentation, characterizing wild populations and conducting seed germination tests. GIS methods were used to locate sites most representative of natural conditions on different post-fire aged veld on a farm in the Kouga mountains. The study characterized habitat conditions by collecting soil and vegetation samples at plots where honeybush was present and absent within close proximity. Vegetation diversity was only slightly higher in presence plots, and no clear pattern between absence and presence plots was observed for soil properties. However, post-fire site age did significantly influence certain nutrient levels. The augmentation trial results indicate that seedlings have a much higher survival rate than seeds on average. Survival success varied unpredictably between plots where wild honeybush was already present and adjacent plots where it was absent. Post-fire site age influenced seedling growth and seed survival positively with the newly burnt plots showing the best growth rates overall. The cost-benefit analysis reveals that seeds are a better option as they require low-cost inputs and carry less risk, unlike seedlings which may have higher survival but are more expensive. The study recommends using trials to assess survival before choosing an option. Out of five natural populations of honeybush that were assessed only one showed seedling recruitment and three young plants were found between two of the other sites. Growth characteristics of populations showed expected variability based on site conditions and disturbance history. Growth appears to be rapid in the first-year post disturbance, thereafter slowing down. Average stem numbers and basal circumference increased concurrently for both harvested and unharvested populations. Due to the influence of natural conditions such as slope aspect and soil properties on plant morphology, it is best to compare harvested and unharvested individuals from the same site and preferably within close proximity to minimize such differences. Using seed sourced from the same parent population is critical to preserving genetic integrity and little is understood about germination characteristics from wild C. intermedia populations. The study tested germination rates between green and brown seed and alternative collection methods. When comparisons were done within farms on two occasions collection and seed colour did have a significant influence. Overall, the influence of which farm the seeds were collected from appeared to play the biggest role in determining germination. , Thesis (MSc) -- Faculty of Science, Geography, 2022
- Full Text: