Thermal physiology of juvenile red roman seabream, Chrysoblephus laticeps after long-term exposure to low pH conditions
- Authors: Allison, Caitlin
- Date: 2023-10-13
- Subjects: Climatic changes , Ocean acidification , Basal metabolism , Chrysoblephus laticeps , Thermal tolerance (Physiology) , Phenotypic plasticity , Fishes Climatic factors
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424323 , vital:72143
- Description: Climate change has caused a combination of effects on the physiology of fishes. Of particular concern are the effects of thermal variability and ocean acidification. Organismal energy budgets change throughout ontogeny and research into the metabolic scope during early life stages is particularly useful in identifying potential bottlenecks. The first part of this thesis aimed to assess the absolute aerobic scope (AAS, described as the difference between the maximum and standard metabolic rates) of individual juveniles from a protected population of the endemic, commercially important seabream, Chrysoblephus laticeps, across a range of ecologically relevant temperatures (T = 11, 14, 18, 22˚C) under present-day conditions (pH = 8.03, pCO2 ≈ 420 μatm) using intermittent flow respirometry. The second component sought to investigate how long-term exposure (from fertilisation to juvenile, ~100 days exposure) to high-pCO2/hypercapnic conditions (pH = 7.63, pCO2 ≈ 1400 μatm), would affect the AAS of juvenile C. laticeps over a range of temperatures. Lower pH conditions were predicted to cause a decrease in the AAS of treatment animals due to additional energetic costs of acid-base regulation. The findings of the first data chapter demonstrated that juvenile C. laticeps reared under current CO2 conditions are tolerant to a wide range of thermal conditions, and individuals with a broad aerobic scope will be the best suited to coping with enhanced thermal variability. In contrast to the expected outcomes of the second data chapter, juvenile C. laticeps reared under high pCO2 conditions displayed greater AAS at high and low temperatures when compared with specimens from high pH conditions. Whilst a high degree of individual phenotypic variation was observed in the metabolic response of both groups, this was reduced at the lower and upper extreme temperatures for high pH and low pH animals respectively. Notably, the variation in treatment animal’s SMR was significantly diminished across all temperatures tested, compared to only a localised reduction in the SMR of high pH animals at cold temperatures. This may be indicative of compensatory pathways affecting energy restructuring and thermally-governed physiological trade-offs under hypercapnia. Given these results, juvenile C. laticeps appear to be more resilient to ocean acidification than anticipated, potentially owing to intrapopulation metabolic phenotypic diversity. This is likely attributed to the parental lineage originating in the Tsitsikamma MPA, which is thought to boast greater phenotypic diversity as a consequence of the refuge that these conservation areas offer from exploitation. Owing to the restriction imposed by the availability of surviving, captive-reared juveniles, the sample size used in this study was relatively low. However, owing to the repeated-measures nature of this research the sample size was sufficient to offer suitable statistical power for the polynomial mixed model used in the analysis. Future research should incorporate both physiological and behavioural responses to multiple environmental stressors to better understand covariation between these two traits, and to detect any behavioural trade-offs that might arise through compensation. In addition, these trials should be repeated using offspring from outside of the MPA to compare whether the same level of resilience and metabolic phenotypic diversity would be present in an exploited population. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Allison, Caitlin
- Date: 2023-10-13
- Subjects: Climatic changes , Ocean acidification , Basal metabolism , Chrysoblephus laticeps , Thermal tolerance (Physiology) , Phenotypic plasticity , Fishes Climatic factors
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424323 , vital:72143
- Description: Climate change has caused a combination of effects on the physiology of fishes. Of particular concern are the effects of thermal variability and ocean acidification. Organismal energy budgets change throughout ontogeny and research into the metabolic scope during early life stages is particularly useful in identifying potential bottlenecks. The first part of this thesis aimed to assess the absolute aerobic scope (AAS, described as the difference between the maximum and standard metabolic rates) of individual juveniles from a protected population of the endemic, commercially important seabream, Chrysoblephus laticeps, across a range of ecologically relevant temperatures (T = 11, 14, 18, 22˚C) under present-day conditions (pH = 8.03, pCO2 ≈ 420 μatm) using intermittent flow respirometry. The second component sought to investigate how long-term exposure (from fertilisation to juvenile, ~100 days exposure) to high-pCO2/hypercapnic conditions (pH = 7.63, pCO2 ≈ 1400 μatm), would affect the AAS of juvenile C. laticeps over a range of temperatures. Lower pH conditions were predicted to cause a decrease in the AAS of treatment animals due to additional energetic costs of acid-base regulation. The findings of the first data chapter demonstrated that juvenile C. laticeps reared under current CO2 conditions are tolerant to a wide range of thermal conditions, and individuals with a broad aerobic scope will be the best suited to coping with enhanced thermal variability. In contrast to the expected outcomes of the second data chapter, juvenile C. laticeps reared under high pCO2 conditions displayed greater AAS at high and low temperatures when compared with specimens from high pH conditions. Whilst a high degree of individual phenotypic variation was observed in the metabolic response of both groups, this was reduced at the lower and upper extreme temperatures for high pH and low pH animals respectively. Notably, the variation in treatment animal’s SMR was significantly diminished across all temperatures tested, compared to only a localised reduction in the SMR of high pH animals at cold temperatures. This may be indicative of compensatory pathways affecting energy restructuring and thermally-governed physiological trade-offs under hypercapnia. Given these results, juvenile C. laticeps appear to be more resilient to ocean acidification than anticipated, potentially owing to intrapopulation metabolic phenotypic diversity. This is likely attributed to the parental lineage originating in the Tsitsikamma MPA, which is thought to boast greater phenotypic diversity as a consequence of the refuge that these conservation areas offer from exploitation. Owing to the restriction imposed by the availability of surviving, captive-reared juveniles, the sample size used in this study was relatively low. However, owing to the repeated-measures nature of this research the sample size was sufficient to offer suitable statistical power for the polynomial mixed model used in the analysis. Future research should incorporate both physiological and behavioural responses to multiple environmental stressors to better understand covariation between these two traits, and to detect any behavioural trade-offs that might arise through compensation. In addition, these trials should be repeated using offspring from outside of the MPA to compare whether the same level of resilience and metabolic phenotypic diversity would be present in an exploited population. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-10-13
Unleashing the nexus between climate change and food security in rural South Africa: role of three community radio stations in the Eastern Cape Province
- Authors: Bamigboye, Foluke Bosede
- Date: 2023-04
- Subjects: Climatic changes , Food security , South Africa -- Rural conditions
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27325 , vital:66939
- Description: This study investigates the role of Forte FM, Mdantsane FM and Rhodes Music Community Radios in disseminating the different kinds of messages on the nexus between the impacts of climate change and food security in the Eastern Cape Province, South Africa. Therefore, the study aims to investigate how these community radio stations play their informative, educative and entertainment roles regarding climate change and food security awareness programmes to their listeners. The study employed the qualitative research approach and convenience, and non-probability samplings techniques were subsequently used to select samples for this study. In-depth interviews were conducted individually for Forte FM, Mdantsane FM and Rhodes Music community radio programme managers respectively, who serve as the key informants. One focus group discussion each was held with residents of Golf Course, Mdantsane and Grahamstown areas where these radio stations broadcast from, with eight participants in each focus group. The total number of participants for the focus group discussions was 24 participants. The collected data were coded into themes using NVivo 12 software to generate the theme nodes and case nodes as key findings, analysis and then interpreted. The findings of this study confirmed that these three community radio stations do contribute to climate change communication through their programmes that focus on climate change and food security related issues. Another vital finding from the study showed that listeners do benefit immensely from these climate change and food security related programmes of the under-study community radio stations. Hence, listeners physical, social, and cognitive well-being of their climatic environment have been greatly impacted. In the same vein, the findings of this study further revealed that the rural communities who are mostly affected by the impacts of climate change on food security have been well informed and enlightened on the suitable ways to enhance a sustainable food security and climate adaptation system through Forte FM, Mdantsane FM, and Rhodes Music community radio stations. Significantly, this study has been able to come up with two suggested models and the conceptual frameworks, which are the Local Action Adaptive Communication (LAAC) Model and the Indigenous Behavioral Change Conceptual (IBCC) Model. These models are focused on increasing listeners interests, adaptation, and behavioral change on climate change issues. The models are also aimed at ensuring better climate change and food security communication Author. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Bamigboye, Foluke Bosede
- Date: 2023-04
- Subjects: Climatic changes , Food security , South Africa -- Rural conditions
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27325 , vital:66939
- Description: This study investigates the role of Forte FM, Mdantsane FM and Rhodes Music Community Radios in disseminating the different kinds of messages on the nexus between the impacts of climate change and food security in the Eastern Cape Province, South Africa. Therefore, the study aims to investigate how these community radio stations play their informative, educative and entertainment roles regarding climate change and food security awareness programmes to their listeners. The study employed the qualitative research approach and convenience, and non-probability samplings techniques were subsequently used to select samples for this study. In-depth interviews were conducted individually for Forte FM, Mdantsane FM and Rhodes Music community radio programme managers respectively, who serve as the key informants. One focus group discussion each was held with residents of Golf Course, Mdantsane and Grahamstown areas where these radio stations broadcast from, with eight participants in each focus group. The total number of participants for the focus group discussions was 24 participants. The collected data were coded into themes using NVivo 12 software to generate the theme nodes and case nodes as key findings, analysis and then interpreted. The findings of this study confirmed that these three community radio stations do contribute to climate change communication through their programmes that focus on climate change and food security related issues. Another vital finding from the study showed that listeners do benefit immensely from these climate change and food security related programmes of the under-study community radio stations. Hence, listeners physical, social, and cognitive well-being of their climatic environment have been greatly impacted. In the same vein, the findings of this study further revealed that the rural communities who are mostly affected by the impacts of climate change on food security have been well informed and enlightened on the suitable ways to enhance a sustainable food security and climate adaptation system through Forte FM, Mdantsane FM, and Rhodes Music community radio stations. Significantly, this study has been able to come up with two suggested models and the conceptual frameworks, which are the Local Action Adaptive Communication (LAAC) Model and the Indigenous Behavioral Change Conceptual (IBCC) Model. These models are focused on increasing listeners interests, adaptation, and behavioral change on climate change issues. The models are also aimed at ensuring better climate change and food security communication Author. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2023
- Full Text:
- Date Issued: 2023-04
Insights into the drivers and impact of climate change and climate change adaptation in the Eastern Cape, South Africa: the case of Amathole District Municipality
- Authors: Gwala, Lindokuhle
- Date: 2022-11
- Subjects: Climatic changes , Climatic factors , Global environmental change
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27832 , vital:69945
- Description: Climate change is a threat to communal livestock production, causing increases in the rate and intensity of droughts, floods, pests and diseases, and thus subjecting communal livestock production to vulnerability. Communal farmers rely on rain-fed agriculture and are usually too poorly resourced to cope with the frequency of climate-related events that may be expected in the future. Response and adaptation is vital to ensure the sustainability of livestock production, particularly since it is the main source of survival in communal areas. The Eastern Cape Provincial Policy on Climate Change was introduced in 2010 to facilitate a coordinated approach that assists farmers to respond, adapt and mitigate climate change. The study examines the implementation of the policy to identify farmers’ perceptions of the response rate prior to, during and after climate change disasters. In addition, the study establishes the characteristics of livestock production in the study area, seeking to ascertain how communal livestock farmers CLFs are adapting their practices to ensure sustainable livestock production in the face of climate change. In order to make informed decisions on coping strategies, farmers require access to information on climate change. The study therefore examines the communication channels used by farmers to access such information. Since food security is under threat, the study also assesses the effects of climate change on food security among the CLFs. Multi stage sampling was used to select 388 communal livestock farmers in three local municipalities in Amathole District Municipality. A cross-sectional survey was carried out in five communities randomly selected in the three local municipalities, with data collected by means of a semi-structured questionnaire. Descriptive statistics, inferential statistics, principal component analysis and regression methods were used to analyse the data. The study reveals that communal livestock farmers perceive a poor response rate from extension services before, during and after disasters, and that they have poor access to support materials. All of the respondents practised uncontrolled breeding, attributed to a lack of infrastructure such as fencing. Most farmers kept cattle for income generation. The major constraints of cattle production were diseases and pests. CLFs employed dipping, rotational grazing, water tanks, veld burning and the sale of animals as the main strategies to cope with climate change. CLFs access climate change information through multiple channels. The main sources were other farmers and media such as radio and television, although language barriers hampered full understanding of information conveyed about climate chnage. Farmer-to-farmer contact was a central aspect of the CLFs’ lives that could be better employed in the dissemination of climate change information. The results suggest a positive relationship between diversity of species kept and food security. Assets, the social safety net (mainly grants) and adaptive capacity indicators positively and significantly impacted households’ resilience to food insecurity. The study recommends that the capacity of communal livestock farmers on effective mitigating strategies be improved, making use of mass media; that more work be done by extension services to prepare farmers for adverse events and that relief materials disseminated during periods of disaster be tagged “national emergency” to speed up distribution and use. There is an urgent need for adequate and timely provision of climate change information that will help CLFs to make more effective use of their resources in the face of climate change. Agricultural extension services should address challenges associated with breeding practices, disaster response and adult illiteracy to promote better adaptive capacity and ensure food security among this vulnerable cohort. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Gwala, Lindokuhle
- Date: 2022-11
- Subjects: Climatic changes , Climatic factors , Global environmental change
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27832 , vital:69945
- Description: Climate change is a threat to communal livestock production, causing increases in the rate and intensity of droughts, floods, pests and diseases, and thus subjecting communal livestock production to vulnerability. Communal farmers rely on rain-fed agriculture and are usually too poorly resourced to cope with the frequency of climate-related events that may be expected in the future. Response and adaptation is vital to ensure the sustainability of livestock production, particularly since it is the main source of survival in communal areas. The Eastern Cape Provincial Policy on Climate Change was introduced in 2010 to facilitate a coordinated approach that assists farmers to respond, adapt and mitigate climate change. The study examines the implementation of the policy to identify farmers’ perceptions of the response rate prior to, during and after climate change disasters. In addition, the study establishes the characteristics of livestock production in the study area, seeking to ascertain how communal livestock farmers CLFs are adapting their practices to ensure sustainable livestock production in the face of climate change. In order to make informed decisions on coping strategies, farmers require access to information on climate change. The study therefore examines the communication channels used by farmers to access such information. Since food security is under threat, the study also assesses the effects of climate change on food security among the CLFs. Multi stage sampling was used to select 388 communal livestock farmers in three local municipalities in Amathole District Municipality. A cross-sectional survey was carried out in five communities randomly selected in the three local municipalities, with data collected by means of a semi-structured questionnaire. Descriptive statistics, inferential statistics, principal component analysis and regression methods were used to analyse the data. The study reveals that communal livestock farmers perceive a poor response rate from extension services before, during and after disasters, and that they have poor access to support materials. All of the respondents practised uncontrolled breeding, attributed to a lack of infrastructure such as fencing. Most farmers kept cattle for income generation. The major constraints of cattle production were diseases and pests. CLFs employed dipping, rotational grazing, water tanks, veld burning and the sale of animals as the main strategies to cope with climate change. CLFs access climate change information through multiple channels. The main sources were other farmers and media such as radio and television, although language barriers hampered full understanding of information conveyed about climate chnage. Farmer-to-farmer contact was a central aspect of the CLFs’ lives that could be better employed in the dissemination of climate change information. The results suggest a positive relationship between diversity of species kept and food security. Assets, the social safety net (mainly grants) and adaptive capacity indicators positively and significantly impacted households’ resilience to food insecurity. The study recommends that the capacity of communal livestock farmers on effective mitigating strategies be improved, making use of mass media; that more work be done by extension services to prepare farmers for adverse events and that relief materials disseminated during periods of disaster be tagged “national emergency” to speed up distribution and use. There is an urgent need for adequate and timely provision of climate change information that will help CLFs to make more effective use of their resources in the face of climate change. Agricultural extension services should address challenges associated with breeding practices, disaster response and adult illiteracy to promote better adaptive capacity and ensure food security among this vulnerable cohort. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
Long-term trends in fish length-at-age, catch-at-length and condition of the Namibian and South African commercially exploited species
- Authors: Iyambo, Elago Martha
- Date: 2022-10-14
- Subjects: Fishery management South Africa , Fishery management Namibia , Fishes Growth , Fisheries Fishing effort , Climatic changes , Fishes Climatic factors
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362872 , vital:65370
- Description: Fish growth rate is a flexible trait that can evolve in response to fishing or environmental change. Therefore, knowledge of fish growth rate patterns, long-term and short-term responses to fishing effort and environmental change is important for fisheries management in the Benguela. Historical and current age length keys have been used as indicators of annual fish growth in the Benguela, the growth rate study on Merluccius paradoxus demonstrated long-term changes in growth over three decades as a response to fishing. However, the fish growth rate patterns, in relation to fishing effort and environmental change patterns are still not known for the many commercially important stocks in the Benguela. The specific objectives of the project were to determine the annual variability and long-term trends, in annual mean lengths-at-age, catch-at-length and fish condition of 17 commercially exploited resources, targeted and bycatch in Namibia and South Africa in relation to environmental changes (sea surface temperature). The results showed that there was a significant decrease in mean length at age 7 for Merluccius capensis (Namibian stock), a significant decrease in mean length at ages 3 to 7 for South African M. capensis and a significant increase in mean length at ages 2 to 6 for South African M. paradoxus Fishery-induced evolution may be the reason for the increase in mean length in the early stages of hake. A regime shift was detected in the mean length at age 1 for Etrumeus whiteheadi (South African stock) caused by changes in water temperatures. A decrease in mean length of the catch was observed for Namibian M. capensis and the reason for this could have been the stock being overexploited during the years of the observed trend (1968 to 1987). Historically both the Namibian Lophius vomerinus and Helicolenus dactylopterus were bycatch of the hake fishery, therefore, the decrease in their mean length of the catch may be due to increased bycatch mortalities due to increased hake catches. The improvement in the management measures of the Jasus lalandii fishery and possible favourable oxygen fluctuation might have caused the stock to increase in mean length of the catch between 1977 and 1982. Fish condition showed a significant difference in stocks between years. Fish condition of M. capensis, M. paradoxus and T. capensis were analysed. The rest of the commercial stocks were omitted because there was limited length-weight data. For Namibian M. capensis the spawning season may have caused fish to have the best condition in 1987 and while higher temperatures in 1983 may have led to the worst condition in 1983. Higher prey availability in 1979 for Namibian M. paradoxus could have been the reason for fish with best condition being found in 1979. T. capensis had the highest condition index in 1986 when cooler summer SST prevailed that may have been more favourable for T. capensis to live in. July, September and January SSTs were significantly negatively correlated with the mean length of M. capensis at age 3. This was perhaps due to upwelling intensity and plankton productivity which increases in winter and decreases in summer. A separate study of the impacts of fishery-induced changes and density-dependence on fish growth rate, as well as the effects of other environmental variables is recommended. Since data for some species was outdated, it is suggested to update biological variables and assessment for future work. This study can be used to understand the key life history characteristics of Namibian and South African exploited resources, targeted and bycatch. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Iyambo, Elago Martha
- Date: 2022-10-14
- Subjects: Fishery management South Africa , Fishery management Namibia , Fishes Growth , Fisheries Fishing effort , Climatic changes , Fishes Climatic factors
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362872 , vital:65370
- Description: Fish growth rate is a flexible trait that can evolve in response to fishing or environmental change. Therefore, knowledge of fish growth rate patterns, long-term and short-term responses to fishing effort and environmental change is important for fisheries management in the Benguela. Historical and current age length keys have been used as indicators of annual fish growth in the Benguela, the growth rate study on Merluccius paradoxus demonstrated long-term changes in growth over three decades as a response to fishing. However, the fish growth rate patterns, in relation to fishing effort and environmental change patterns are still not known for the many commercially important stocks in the Benguela. The specific objectives of the project were to determine the annual variability and long-term trends, in annual mean lengths-at-age, catch-at-length and fish condition of 17 commercially exploited resources, targeted and bycatch in Namibia and South Africa in relation to environmental changes (sea surface temperature). The results showed that there was a significant decrease in mean length at age 7 for Merluccius capensis (Namibian stock), a significant decrease in mean length at ages 3 to 7 for South African M. capensis and a significant increase in mean length at ages 2 to 6 for South African M. paradoxus Fishery-induced evolution may be the reason for the increase in mean length in the early stages of hake. A regime shift was detected in the mean length at age 1 for Etrumeus whiteheadi (South African stock) caused by changes in water temperatures. A decrease in mean length of the catch was observed for Namibian M. capensis and the reason for this could have been the stock being overexploited during the years of the observed trend (1968 to 1987). Historically both the Namibian Lophius vomerinus and Helicolenus dactylopterus were bycatch of the hake fishery, therefore, the decrease in their mean length of the catch may be due to increased bycatch mortalities due to increased hake catches. The improvement in the management measures of the Jasus lalandii fishery and possible favourable oxygen fluctuation might have caused the stock to increase in mean length of the catch between 1977 and 1982. Fish condition showed a significant difference in stocks between years. Fish condition of M. capensis, M. paradoxus and T. capensis were analysed. The rest of the commercial stocks were omitted because there was limited length-weight data. For Namibian M. capensis the spawning season may have caused fish to have the best condition in 1987 and while higher temperatures in 1983 may have led to the worst condition in 1983. Higher prey availability in 1979 for Namibian M. paradoxus could have been the reason for fish with best condition being found in 1979. T. capensis had the highest condition index in 1986 when cooler summer SST prevailed that may have been more favourable for T. capensis to live in. July, September and January SSTs were significantly negatively correlated with the mean length of M. capensis at age 3. This was perhaps due to upwelling intensity and plankton productivity which increases in winter and decreases in summer. A separate study of the impacts of fishery-induced changes and density-dependence on fish growth rate, as well as the effects of other environmental variables is recommended. Since data for some species was outdated, it is suggested to update biological variables and assessment for future work. This study can be used to understand the key life history characteristics of Namibian and South African exploited resources, targeted and bycatch. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
Towards an improved understanding of episodic benthic turbidity events (Benthic Nepheloid Layer) on the Eastern Agulhas Bank, South Africa
- Authors: Johnstone, Brett Mordaunt
- Date: 2022-10-14
- Subjects: Nepheloid layer , Turbidity , Loligo reynaudii , Fisheries South Africa , Oceanography , Remote sensing , Altimetry , Climatic changes
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362883 , vital:65371
- Description: The harvest of Loligo reynaudii, or "chokka," represents a critical source of revenue and job creation in the historically impoverished Eastern Cape Province of South Africa. Due to the importance of visual stimuli in the reproductive processes, it has been hypothesized that a primary driver of successful reproduction is the clarity of the water column. The presence of increased particulate matter concentrations within the water column generates turbid conditions near the seafloor (visibility < 1m), that are proposed to restrict spawning activity. This benthic nepheloid layer (BNL) contains both organic and inorganic components, with the BNL intensity a function of bottom turbulence, substratum type, and detritus level. However, the spatial and temporal resolution of BNL intensity on the Eastern Agulhas Bank (EAB) and the environmental drivers thereof remain unknown. Here we show that benthic turbidity events are a common but highly variable occurrence on the EAB. Results from a 17-month time-series of in-situ and remote sensing data between 2002 – 2004 in Algoa Bay, supplemented by experiments in other bays important for spawning, show that turbid conditions existed for ∼ 30 % of the sample period. Exploration of environmental drivers, including the influence of wind, altimeter-derived significant wave height (Hs), sea surface temperature (SST), and chlorophyll-a (Chl-a) concentrations indicate that BNL intensity does not conform to a "one-size-fits-all" approach. Rather, complex local hydrological and physiochemical parameters control the BNL characteristics on the EAB. Global warming is likely to increase the frequency and intensity of extreme westerly-wind and storm events, promoting BNL events on the Eastern Agulhas Bank and possibly causing a shift in the reproductive strategy of chokka squid to the cooler mid shelf region. This is likely to have consequences for both the species in terms of reproductive success and the fishery, which is concentrated on inshore spawning aggregations. Future research needs to quantify and characterize the constituents, source particles and spatial-temporal variability of BNL events in order to build a predictive capacity. Through incorporating the qualitative analysis of the dynamics of nepheloid layers on the EAB into Regional Oceanographic Models (ROMS), General Linear Models (GLM) and particle distribution models such as DELFT-3D, it is possible to move toward predicting the timing and intensity of these events. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Johnstone, Brett Mordaunt
- Date: 2022-10-14
- Subjects: Nepheloid layer , Turbidity , Loligo reynaudii , Fisheries South Africa , Oceanography , Remote sensing , Altimetry , Climatic changes
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362883 , vital:65371
- Description: The harvest of Loligo reynaudii, or "chokka," represents a critical source of revenue and job creation in the historically impoverished Eastern Cape Province of South Africa. Due to the importance of visual stimuli in the reproductive processes, it has been hypothesized that a primary driver of successful reproduction is the clarity of the water column. The presence of increased particulate matter concentrations within the water column generates turbid conditions near the seafloor (visibility < 1m), that are proposed to restrict spawning activity. This benthic nepheloid layer (BNL) contains both organic and inorganic components, with the BNL intensity a function of bottom turbulence, substratum type, and detritus level. However, the spatial and temporal resolution of BNL intensity on the Eastern Agulhas Bank (EAB) and the environmental drivers thereof remain unknown. Here we show that benthic turbidity events are a common but highly variable occurrence on the EAB. Results from a 17-month time-series of in-situ and remote sensing data between 2002 – 2004 in Algoa Bay, supplemented by experiments in other bays important for spawning, show that turbid conditions existed for ∼ 30 % of the sample period. Exploration of environmental drivers, including the influence of wind, altimeter-derived significant wave height (Hs), sea surface temperature (SST), and chlorophyll-a (Chl-a) concentrations indicate that BNL intensity does not conform to a "one-size-fits-all" approach. Rather, complex local hydrological and physiochemical parameters control the BNL characteristics on the EAB. Global warming is likely to increase the frequency and intensity of extreme westerly-wind and storm events, promoting BNL events on the Eastern Agulhas Bank and possibly causing a shift in the reproductive strategy of chokka squid to the cooler mid shelf region. This is likely to have consequences for both the species in terms of reproductive success and the fishery, which is concentrated on inshore spawning aggregations. Future research needs to quantify and characterize the constituents, source particles and spatial-temporal variability of BNL events in order to build a predictive capacity. Through incorporating the qualitative analysis of the dynamics of nepheloid layers on the EAB into Regional Oceanographic Models (ROMS), General Linear Models (GLM) and particle distribution models such as DELFT-3D, it is possible to move toward predicting the timing and intensity of these events. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
Acceleration of Climate Change and the Impact on the Built Environment
- Authors: Van Rooyen, Mauritz Kenneth
- Date: 2022-04
- Subjects: Climatic changes , Natural disasters
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58532 , vital:59751
- Description: Climate change is widely acknowledged as one of humanity's most pressing problems in the twenty-first century. The emission of greenhouse gases (GHGs) has changed the earth's normal climate cycle by raising the earth's surface temperature. The severity and frequency of various natural catastrophes, such as storms, floods, heat waves, and droughts, have increased as the earth's surface temperature has risen. These events have a devastating effect on populated areas; contaminating clean drinking water, leading to uncontrollable wildfires, damaging properties and infrastructure, environmental pollution, and loss of life. The increase in GHG emissions is largely contributed to by the built environment and the human activities within these areas. This research aimed to investigate the current state of climate change and the impact on the built environment. Furthermore, a quantitative approach was taken with regards to the research and a descriptive survey was conducted among professionals that work within the built environment, namely architects, project managers, construction managers, and electrical and mechanical engineers. The salient findings are: very few participants actively participate in activities to enhance their knowledge of climate change; most participants have a good understanding of what climate change is, although they make no extra effort to implement mitigating strategies on their projects other than what is required by the local council; most participants are unsure with respect to the impact that climate change has on the built environment, and most participants are unaware of global initiatives that South Africa has contributed to, to reduce GHG emissions. Governments and organisations around the world have implemented rules and regulations to regulate and decrease GHGs in the atmosphere, but it is still increasing at an accelerated rate. The increase of GHG emissions is devastating on all sectors of the built environment and will only intensify over time. As advancements are made to reduce GHG emissions progress has also been made to adapt to an ever-changing climate, specifically in the construction industry. Architecture and building processes have evolved to not only reduce the harmful effects on the environment but also to be more efficient and sustainable. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Van Rooyen, Mauritz Kenneth
- Date: 2022-04
- Subjects: Climatic changes , Natural disasters
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58532 , vital:59751
- Description: Climate change is widely acknowledged as one of humanity's most pressing problems in the twenty-first century. The emission of greenhouse gases (GHGs) has changed the earth's normal climate cycle by raising the earth's surface temperature. The severity and frequency of various natural catastrophes, such as storms, floods, heat waves, and droughts, have increased as the earth's surface temperature has risen. These events have a devastating effect on populated areas; contaminating clean drinking water, leading to uncontrollable wildfires, damaging properties and infrastructure, environmental pollution, and loss of life. The increase in GHG emissions is largely contributed to by the built environment and the human activities within these areas. This research aimed to investigate the current state of climate change and the impact on the built environment. Furthermore, a quantitative approach was taken with regards to the research and a descriptive survey was conducted among professionals that work within the built environment, namely architects, project managers, construction managers, and electrical and mechanical engineers. The salient findings are: very few participants actively participate in activities to enhance their knowledge of climate change; most participants have a good understanding of what climate change is, although they make no extra effort to implement mitigating strategies on their projects other than what is required by the local council; most participants are unsure with respect to the impact that climate change has on the built environment, and most participants are unaware of global initiatives that South Africa has contributed to, to reduce GHG emissions. Governments and organisations around the world have implemented rules and regulations to regulate and decrease GHGs in the atmosphere, but it is still increasing at an accelerated rate. The increase of GHG emissions is devastating on all sectors of the built environment and will only intensify over time. As advancements are made to reduce GHG emissions progress has also been made to adapt to an ever-changing climate, specifically in the construction industry. Architecture and building processes have evolved to not only reduce the harmful effects on the environment but also to be more efficient and sustainable. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
Feminization of agriculture, livelihoods and climate change in Chivi district, Zimbabwe
- Authors: Muzapi, Admire
- Date: 2022-04
- Subjects: Climatic changes , Women in agriculture
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58002 , vital:58489
- Description: Given the historically disadvantaged position of women and their heavy reliance on climate-sensitive activities in many societies, the vagaries of the climate threaten the agrarian livelihoods of women in Chivi district. This study focuses on the impacts of climate change on women working in agriculture in one ward of Chivi district and on the feminization of agriculture during the period from 2000 to 2019. It explores how the roles of women have changed in agricultural production and in relation to household food security. It assesses women’s involvement in decision-making in agriculture as well as in household food security, and analyses the socio-economic impacts of climate change on women subsistence farmers, exploring the adaptation strategies that rural women working in agriculture implement in response to climate-risk events and threats. The study was influenced by ecofeminist theories and the Sustainable Livelihood Framework. Comparative analysis of household types was done after data gathering using participatory rural appraisal tools with women from three villages. Interviews were conducted with key informants from government departments and development institutions. The results show that climate-risk events and threats have resulted in feminization of agricultural labour as men branch out into wage labour, but that changing power relations in the form of decision-making in agriculture and issues related to household food security vary with the type of the household. Worsening climatic conditions have made it difficult for women to ensure household food security and to generate income through agrarian livelihoods. However, women have implemented adaptation strategies including conservation agriculture to mitigate crop failure, and to improve agricultural output and household daily consumption, and thus survive peak hunger periods. The study contributes to our understanding of the resilience of women in the Global South to climate-risk events and threats and contributes to our understanding of participatory rural appraisal tools in addition to conventional data collection tools. The study recommends that development institutions promote gender equality and that development institutions construct dams, rehabilitate collapsed irrigation schemes and accelerate the implementation of novel climate smart technologies in arid regions. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Muzapi, Admire
- Date: 2022-04
- Subjects: Climatic changes , Women in agriculture
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58002 , vital:58489
- Description: Given the historically disadvantaged position of women and their heavy reliance on climate-sensitive activities in many societies, the vagaries of the climate threaten the agrarian livelihoods of women in Chivi district. This study focuses on the impacts of climate change on women working in agriculture in one ward of Chivi district and on the feminization of agriculture during the period from 2000 to 2019. It explores how the roles of women have changed in agricultural production and in relation to household food security. It assesses women’s involvement in decision-making in agriculture as well as in household food security, and analyses the socio-economic impacts of climate change on women subsistence farmers, exploring the adaptation strategies that rural women working in agriculture implement in response to climate-risk events and threats. The study was influenced by ecofeminist theories and the Sustainable Livelihood Framework. Comparative analysis of household types was done after data gathering using participatory rural appraisal tools with women from three villages. Interviews were conducted with key informants from government departments and development institutions. The results show that climate-risk events and threats have resulted in feminization of agricultural labour as men branch out into wage labour, but that changing power relations in the form of decision-making in agriculture and issues related to household food security vary with the type of the household. Worsening climatic conditions have made it difficult for women to ensure household food security and to generate income through agrarian livelihoods. However, women have implemented adaptation strategies including conservation agriculture to mitigate crop failure, and to improve agricultural output and household daily consumption, and thus survive peak hunger periods. The study contributes to our understanding of the resilience of women in the Global South to climate-risk events and threats and contributes to our understanding of participatory rural appraisal tools in addition to conventional data collection tools. The study recommends that development institutions promote gender equality and that development institutions construct dams, rehabilitate collapsed irrigation schemes and accelerate the implementation of novel climate smart technologies in arid regions. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Greening Ndlambe Village
- Authors: Vithi-Masiza, Noluthando
- Date: 2022-04
- Subjects: Climatic changes , Sustainable development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58396 , vital:59082
- Description: In 1994 the new democratic government of South Africa introduced the Reconstruction and Development Programme (RDP) which was aimed at massive infrastructure expansion. Tackling the housing crisis has been encountered by growing demands for low carbon footprint, reduced use of non-renewable resources and as part of the green agenda. In line with the Sustainable Development Goals (SDGs), the South African government set a variety of objectives aimed at achieving an environmentally sustainable future for all. While South Africa has embraced green economy principles, tested integrated approaches are still to be seen in housing construction. This study sought to explore the greening of Ndlambe green village in the Port Alfred area in the Eastern Cape Province of South Africa. To achieve the study objectives, a qualitative research approach was used, employing the case study research strategy and primary data was collected by means of focus groups. Community members, engineers, environmentalists and town planners constituted the study sample. Secondary data sources were also used in this study, along with field observation. The collected data was analysed using the thematic analysis technique. Findings from the study revealed that community members perceived Green village initiative as important and is required in South Africa given the challenges that are experienced such as energy consumption load shedding, water shortages. The economic value proposition of green building is measured through two different lenses, namely economic profit and social profit. The municipalities must take a leading role in by forming policies supporting environmentally friendly activities, with building being one crucial area. Recommendations from the study proposed that partnerships involving communities, private companies, the government and other various interest groups are imperative in order to accelerating the green building agenda. The government must be challenges to develop sustainable funding solutions for a green economy. Lastly, increased awareness about green building among the society may also drive better acceptability and ultimately, a strong social reputation. , Thesis (PhD) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Vithi-Masiza, Noluthando
- Date: 2022-04
- Subjects: Climatic changes , Sustainable development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58396 , vital:59082
- Description: In 1994 the new democratic government of South Africa introduced the Reconstruction and Development Programme (RDP) which was aimed at massive infrastructure expansion. Tackling the housing crisis has been encountered by growing demands for low carbon footprint, reduced use of non-renewable resources and as part of the green agenda. In line with the Sustainable Development Goals (SDGs), the South African government set a variety of objectives aimed at achieving an environmentally sustainable future for all. While South Africa has embraced green economy principles, tested integrated approaches are still to be seen in housing construction. This study sought to explore the greening of Ndlambe green village in the Port Alfred area in the Eastern Cape Province of South Africa. To achieve the study objectives, a qualitative research approach was used, employing the case study research strategy and primary data was collected by means of focus groups. Community members, engineers, environmentalists and town planners constituted the study sample. Secondary data sources were also used in this study, along with field observation. The collected data was analysed using the thematic analysis technique. Findings from the study revealed that community members perceived Green village initiative as important and is required in South Africa given the challenges that are experienced such as energy consumption load shedding, water shortages. The economic value proposition of green building is measured through two different lenses, namely economic profit and social profit. The municipalities must take a leading role in by forming policies supporting environmentally friendly activities, with building being one crucial area. Recommendations from the study proposed that partnerships involving communities, private companies, the government and other various interest groups are imperative in order to accelerating the green building agenda. The government must be challenges to develop sustainable funding solutions for a green economy. Lastly, increased awareness about green building among the society may also drive better acceptability and ultimately, a strong social reputation. , Thesis (PhD) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
The role of climate change on food security in Northern Uganda a case study of Lira district
- Authors: Aciro, Prudence Estel
- Date: 2022-04
- Subjects: Food security -- Uganda , Food security -- Climatic factors , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57513 , vital:58054
- Description: The study examines the effects of climate change in Northern Uganda to create food security solutions through the improvement of local resilience mechanisms and adaptation devices. The study adopted the interpretive paradigm within the qualitative research methodology as it investigated the subjective opinions of the respondents about the role of climate change on food security in the Lira district. The researcher used non-probability purposive sampling to identify nine officials that possessed knowledge on resilience mechanisms and also interacted directly with individual farmers. The researcher used semi-structured interviews as a tool to collect data and thematic analysis to make conclusions on findings based on the emerging themes. The findings from the study revealed that the four determinants of food security are greatly affected by climate events and these are: food utilisation, food production, food availability and access to food as well as the stability of food supply. Food storage is a problem facing the community of Lira due to extreme climate events. Climate change was found to affect food prices in such a way that when agricultural inputs are bought expensively, it leads the cost of producing crops to increase, which in turn makes food more expensive at the market. The findings also displayed that Lira’s local communities are trying to apply adaptive farming practices to ensure there is an adequate food supply, such as planting a local variety of seeds that withstand the effect of climate change, such as sorghum millet and cassava. Based on the findings, valuable recommendations are offered. These include the government rolling out a national irrigation scheme to ease the use of the drip irrigation mechanism. Also, there is a need for more interventions that support local resilience mechanisms such as the use of agricultural inputs, as these require subsidisation. It emerged from the findings of this study that there is a need for better interventions to deal with flooding. For future researchers, it was found that there is a need to explore the best post-harvest handling methods as well as food storage. , Thesis (MA) -- Faculty of Business and Economic Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Aciro, Prudence Estel
- Date: 2022-04
- Subjects: Food security -- Uganda , Food security -- Climatic factors , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57513 , vital:58054
- Description: The study examines the effects of climate change in Northern Uganda to create food security solutions through the improvement of local resilience mechanisms and adaptation devices. The study adopted the interpretive paradigm within the qualitative research methodology as it investigated the subjective opinions of the respondents about the role of climate change on food security in the Lira district. The researcher used non-probability purposive sampling to identify nine officials that possessed knowledge on resilience mechanisms and also interacted directly with individual farmers. The researcher used semi-structured interviews as a tool to collect data and thematic analysis to make conclusions on findings based on the emerging themes. The findings from the study revealed that the four determinants of food security are greatly affected by climate events and these are: food utilisation, food production, food availability and access to food as well as the stability of food supply. Food storage is a problem facing the community of Lira due to extreme climate events. Climate change was found to affect food prices in such a way that when agricultural inputs are bought expensively, it leads the cost of producing crops to increase, which in turn makes food more expensive at the market. The findings also displayed that Lira’s local communities are trying to apply adaptive farming practices to ensure there is an adequate food supply, such as planting a local variety of seeds that withstand the effect of climate change, such as sorghum millet and cassava. Based on the findings, valuable recommendations are offered. These include the government rolling out a national irrigation scheme to ease the use of the drip irrigation mechanism. Also, there is a need for more interventions that support local resilience mechanisms such as the use of agricultural inputs, as these require subsidisation. It emerged from the findings of this study that there is a need for better interventions to deal with flooding. For future researchers, it was found that there is a need to explore the best post-harvest handling methods as well as food storage. , Thesis (MA) -- Faculty of Business and Economic Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Effects of climatic variability on maize productivity in South Africa from 1937-2018
- Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Authors: Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Date: 2022-03
- Subjects: Crops and climate , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21410 , vital:48576
- Description: Climate is an important factor in agricultural production. The world is facing climate change and variability, which result in high temperatures, low rainfall patterns, shortage of water and persistent droughts. Climate change poses a significant threat to South Africa’s water resources, food security, health, infrastructure, ecosystem services and biodiversity. Negative impacts of climate variability on agriculture, especially on maize the staple crop, will worsen the food security status of the nation as most of South Africa’s maize crop is produced in summer and highly depends on rainfall. This study attempted to assess the impact of climate on maize production in South Africa using secondary time series data for the period 1937 to 2018. Rainfall and temperature were used as proxies for climate variability. The Granger Causality Model was used to examine the causal linkages between climatic variables (temperature or rainfall) and maize output in South Africa for the study period. The major outcome of the analysis was that there is a two-way causal relationship between maize production and temperature. The results also indicated that there is uni-directional causality between maize yield and rainfall. Furthermore, the Variance Decomposition Model was used to forecast the relationship between climatic elements and maize production in South Africa. The result showed that all variables have an effect on maize yield, with temperature having the least effect. The last objective of the study was to profile the maize output trend for the period from 1937 to 2018. The main findings from the analysis indicate that maize production in South Africa has a general upward slope. The study recommends that the government should intensify the provision of irrigation systems for the farmers in the most vulnerable areas to mitigate the climate change. Government should also embark on massive campaigns using a variety of media to create the needed public awareness on climate change and its impact on food security. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Date: 2022-03
- Subjects: Crops and climate , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21410 , vital:48576
- Description: Climate is an important factor in agricultural production. The world is facing climate change and variability, which result in high temperatures, low rainfall patterns, shortage of water and persistent droughts. Climate change poses a significant threat to South Africa’s water resources, food security, health, infrastructure, ecosystem services and biodiversity. Negative impacts of climate variability on agriculture, especially on maize the staple crop, will worsen the food security status of the nation as most of South Africa’s maize crop is produced in summer and highly depends on rainfall. This study attempted to assess the impact of climate on maize production in South Africa using secondary time series data for the period 1937 to 2018. Rainfall and temperature were used as proxies for climate variability. The Granger Causality Model was used to examine the causal linkages between climatic variables (temperature or rainfall) and maize output in South Africa for the study period. The major outcome of the analysis was that there is a two-way causal relationship between maize production and temperature. The results also indicated that there is uni-directional causality between maize yield and rainfall. Furthermore, the Variance Decomposition Model was used to forecast the relationship between climatic elements and maize production in South Africa. The result showed that all variables have an effect on maize yield, with temperature having the least effect. The last objective of the study was to profile the maize output trend for the period from 1937 to 2018. The main findings from the analysis indicate that maize production in South Africa has a general upward slope. The study recommends that the government should intensify the provision of irrigation systems for the farmers in the most vulnerable areas to mitigate the climate change. Government should also embark on massive campaigns using a variety of media to create the needed public awareness on climate change and its impact on food security. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
A framework for communicating climate information to rural small-scale farmers in the Eastern Cape Province, South Africa using systems thinking approach
- Pindura, Tineyi Herbert https://orcid.org/0000-0001-7233-6222
- Authors: Pindura, Tineyi Herbert https://orcid.org/0000-0001-7233-6222
- Date: 2022-02
- Subjects: Farms, Small , Agriculture -- Environmental aspects , Climatic changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22809 , vital:52784
- Description: In the Eastern Cape of South Africa, rural small-scale farmers live in uncertain times characterized by climate change and variability, which intensify social, political and financial inequalities. Therefore, there is a need to increase the understanding and interpretation of climate information to minimize crop production risk, reduce rural small-scale farmers’ vulnerability to climate, and maximize opportunities. Increasing the resilience among rural small-scale farmers requires appropriate and viable practical approaches. By using systems thinking approach (and the Raymond Mhlaba Municipality in the Eastern Cape as a study area), this research disseminates the complex nature of current climate information frameworks. Through inputs from farmers (through a Farmers Research Group methodology) and climate data, this thesis developed a new framework for communicating climate information (herein referred as the climate information communication systems framework) to rural small-scale farmers. The proposed climate information communication systems framework successfully integrates scientific and traditional knowledge. The framework constitutes certain stages, where the farming system and crop identification is the first stage. The second stage is the requirements stage, which has two relationships: scientist to crop requirements and farmers to crop requirements. At the scientist to crop requirements level, users will examine crop requirements by combining climatic data and crop simulations, while at the farmers to crop requirement, rural small-scale farmers use the scientific information to plan for the farming season. The farmer then decides the planting and growing period as well as the harvest timing. The study suggests that building links between rural small-scale farmers, extension officers, and scientists makes sharing information easier. The proposed climate information framework design illustrates that stakeholders now have a personal relationship with climate information transmission and can influence the different actions to reduce the effect of climate change unpredictability. The study established that climate change and variability influence recent agricultural output trends. Recent temperature and rainfall trends could have resulted in low crop productivity in the study area. The study also reflected that women are a critical resource in agriculture and rural economy and that middle-aged men and youth are less interested in farming. The findings also showed that women are more receptive to climate information; hence, to promote access and use of climate information remains vital to consider gender-specific aspects for appropriate decision-making in the agriculture sector. The study also recommends enhancing the Farmers Research Group technique. In the past, the scope of this methodology has been narrowly focused, and it must be explored to incorporate additional types of climate information and more debate about how climate is related to the decisions farmers for implementation or consideration. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-02
- Authors: Pindura, Tineyi Herbert https://orcid.org/0000-0001-7233-6222
- Date: 2022-02
- Subjects: Farms, Small , Agriculture -- Environmental aspects , Climatic changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22809 , vital:52784
- Description: In the Eastern Cape of South Africa, rural small-scale farmers live in uncertain times characterized by climate change and variability, which intensify social, political and financial inequalities. Therefore, there is a need to increase the understanding and interpretation of climate information to minimize crop production risk, reduce rural small-scale farmers’ vulnerability to climate, and maximize opportunities. Increasing the resilience among rural small-scale farmers requires appropriate and viable practical approaches. By using systems thinking approach (and the Raymond Mhlaba Municipality in the Eastern Cape as a study area), this research disseminates the complex nature of current climate information frameworks. Through inputs from farmers (through a Farmers Research Group methodology) and climate data, this thesis developed a new framework for communicating climate information (herein referred as the climate information communication systems framework) to rural small-scale farmers. The proposed climate information communication systems framework successfully integrates scientific and traditional knowledge. The framework constitutes certain stages, where the farming system and crop identification is the first stage. The second stage is the requirements stage, which has two relationships: scientist to crop requirements and farmers to crop requirements. At the scientist to crop requirements level, users will examine crop requirements by combining climatic data and crop simulations, while at the farmers to crop requirement, rural small-scale farmers use the scientific information to plan for the farming season. The farmer then decides the planting and growing period as well as the harvest timing. The study suggests that building links between rural small-scale farmers, extension officers, and scientists makes sharing information easier. The proposed climate information framework design illustrates that stakeholders now have a personal relationship with climate information transmission and can influence the different actions to reduce the effect of climate change unpredictability. The study established that climate change and variability influence recent agricultural output trends. Recent temperature and rainfall trends could have resulted in low crop productivity in the study area. The study also reflected that women are a critical resource in agriculture and rural economy and that middle-aged men and youth are less interested in farming. The findings also showed that women are more receptive to climate information; hence, to promote access and use of climate information remains vital to consider gender-specific aspects for appropriate decision-making in the agriculture sector. The study also recommends enhancing the Farmers Research Group technique. In the past, the scope of this methodology has been narrowly focused, and it must be explored to incorporate additional types of climate information and more debate about how climate is related to the decisions farmers for implementation or consideration. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-02
The use of earth observation multi-sensor systems to monitor and model Pastures: a case of Savannah Grasslands in Hluvukani Village, Bushbuckridge Local Municipality, Mpumalanga Province, South Africa
- Nduku, Lwandile https://orcid.org/0000-0001-9168-4548
- Authors: Nduku, Lwandile https://orcid.org/0000-0001-9168-4548
- Date: 2022-01
- Subjects: Climatic changes , Grassland conservation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22578 , vital:52470
- Description: Grassland degradation associated with climate change and inappropriate grassland management has been characterized as a global environmental concern driving decreased grassland ecosystem's ecological functioning. More than 60% of South African grassland is degraded or permanently transformed to other land uses and nearly 2% properly conserved. Yet, grasslands are a major source of food for livestock grazing and provide material and non-material benefits to many livelihoods. Therefore, grassland above-ground biomass (AGB) estimation is crucial in planning and managing pastoral agriculture and the benefits derived from it. However, current grassland monitoring techniques used in rural smallholder livestock farms rely on conventional methods, which are destructive, labour-intensive, costly, and restricted to small areas. This study investigated the monitoring and modelling of protected grasslands biomass using current Earth observation systems (EOS), an approach, which is non-destructive, cost-effective, cover larger areas and is a time-saving alternative to conventional methods. Hence, the research objectives were: (i) to map the trends and advances in data and models used in the monitoring of grassland (pastures) with Earth observation systems, and (ii) to assess above-ground biomass estimation in semi-arid savannah grassland integrating Sentinel-1 and Sentinel-2 data with Machine-Learning. This goal was to assess if this approach could provide the requisite information, which could contribute to the long-term goal of developing a semi-automated system for data processing, and mapping grassland biomass to benefit local communities. For this investigation, it was crucial to understanding what research had achieved so far in this area of pasture management. An assessment of the Scopus database showed the recent developments in European Union (EU) programs and Sentinel missions, including statistical models and machine learning for monitoring grassland changes at multiple scales. However, Sentinel-1 and Sentinel-2 data, machine learning models, and variable importance techniques were applied for grassland AGB estimation. These techniques have been used in similar studies to determine optimum machine learning models, influential variables, and the capability of integrated Sentinel datasets for mapping grassland AGB, spatial distribution, and abundance. Results showed improved performance with the Random forest regression (RFR) model (R² of 34.7%, RMSE of 9.47 Mg and MAE of 7.68 Mg ). The study also observed optimum sensitivity of Difference Vegetation Index (DVI) and Enhanced Vegetation Index (EVI) in all three machine learning models for modelling grassland AGB estimation in the study area. A further, statistical comparison of all three machine learning models showed an insignificant difference in the predictive capacity for AGB in the study area with Gradient Boosting regression (GBR) model (R² of 27.7, RMSE of 9.97 Mg and MAE of 8.03 Mg ) and Extreme Gradient Boost Regression (XGBR) model (R² of 17.3%, RMSE of 10.66 Mg and MAE of 8.83 Mg ). The study revealed that an integration of Sentinel-1 and Sentinel-2 has improved capabilities for monitoring grassland AGB estimation. This research sheds light on the timely and cost-effective techniques for grassland management strategies to enhance or restore the ecological functioning of grassland ecosystems and promote community sustainability. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-01
- Authors: Nduku, Lwandile https://orcid.org/0000-0001-9168-4548
- Date: 2022-01
- Subjects: Climatic changes , Grassland conservation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22578 , vital:52470
- Description: Grassland degradation associated with climate change and inappropriate grassland management has been characterized as a global environmental concern driving decreased grassland ecosystem's ecological functioning. More than 60% of South African grassland is degraded or permanently transformed to other land uses and nearly 2% properly conserved. Yet, grasslands are a major source of food for livestock grazing and provide material and non-material benefits to many livelihoods. Therefore, grassland above-ground biomass (AGB) estimation is crucial in planning and managing pastoral agriculture and the benefits derived from it. However, current grassland monitoring techniques used in rural smallholder livestock farms rely on conventional methods, which are destructive, labour-intensive, costly, and restricted to small areas. This study investigated the monitoring and modelling of protected grasslands biomass using current Earth observation systems (EOS), an approach, which is non-destructive, cost-effective, cover larger areas and is a time-saving alternative to conventional methods. Hence, the research objectives were: (i) to map the trends and advances in data and models used in the monitoring of grassland (pastures) with Earth observation systems, and (ii) to assess above-ground biomass estimation in semi-arid savannah grassland integrating Sentinel-1 and Sentinel-2 data with Machine-Learning. This goal was to assess if this approach could provide the requisite information, which could contribute to the long-term goal of developing a semi-automated system for data processing, and mapping grassland biomass to benefit local communities. For this investigation, it was crucial to understanding what research had achieved so far in this area of pasture management. An assessment of the Scopus database showed the recent developments in European Union (EU) programs and Sentinel missions, including statistical models and machine learning for monitoring grassland changes at multiple scales. However, Sentinel-1 and Sentinel-2 data, machine learning models, and variable importance techniques were applied for grassland AGB estimation. These techniques have been used in similar studies to determine optimum machine learning models, influential variables, and the capability of integrated Sentinel datasets for mapping grassland AGB, spatial distribution, and abundance. Results showed improved performance with the Random forest regression (RFR) model (R² of 34.7%, RMSE of 9.47 Mg and MAE of 7.68 Mg ). The study also observed optimum sensitivity of Difference Vegetation Index (DVI) and Enhanced Vegetation Index (EVI) in all three machine learning models for modelling grassland AGB estimation in the study area. A further, statistical comparison of all three machine learning models showed an insignificant difference in the predictive capacity for AGB in the study area with Gradient Boosting regression (GBR) model (R² of 27.7, RMSE of 9.97 Mg and MAE of 8.03 Mg ) and Extreme Gradient Boost Regression (XGBR) model (R² of 17.3%, RMSE of 10.66 Mg and MAE of 8.83 Mg ). The study revealed that an integration of Sentinel-1 and Sentinel-2 has improved capabilities for monitoring grassland AGB estimation. This research sheds light on the timely and cost-effective techniques for grassland management strategies to enhance or restore the ecological functioning of grassland ecosystems and promote community sustainability. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-01
Investigating the feasibility of using remote sensing in index-based crop insurance for South Africa’s smallholder farming systems
- Masiza, Wonga https://orcid.org/0000-0002-6224-3812
- Authors: Masiza, Wonga https://orcid.org/0000-0002-6224-3812
- Date: 2021-10
- Subjects: Precision farming , Agricultural engineering , Climatic changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23000 , vital:54890
- Description: Crop farming in Sub-Saharan Africa (SSA) is largely practiced by resource-poor farmers under rain-fed and unpredictable weather conditions. Since agriculture is the mainstay of SSA’s economy, the lack of improved and adapted agricultural technologies in this region sets back economic development and the fight against poverty. Overcoming this constraint and achieving the sustainable development goal to end poverty, requires innovative tools that can be used for weather risk management. One tool that has been gaining momentum recently is index-based crop insurance (IBCI). Since the launch of the first IBCI program in Africa around 2005, the number of IBCI programs has increased. Unfortunately, these programs are constrained by poor product design, basis risk, and low uptake of contracts. When these issues were first pointed-out in the earliest IBCI programs, many reports suggested satellite remote sensing (RS) as a viable solution. Hence, the first objective of this study was to assess how RS has been used in IBCI, the challenges RS faces, and potential contributions of RS that have not yet been meaningfully exploited. The literature shows that IBCI programs are increasingly adopting RS. RS has improved demarcation of unit areas of insurance and enabled IBCI to reach inaccessible areas that do not have sufficient meteorological infrastructure. However, the literature also shows that IBCI is still tainted by basis risk, which emanates from poor contract designs, the influence of non-weather factors on crop yields, imperfect correlations between satellite-based indices and crop yields, and the lack of historical data for calibration. Although IBCI reports cover vegetation and crop health monitoring, few to none cover crop type and crop area mapping. Furthermore, areas including high-resolution mapping, data fusion, microwave RS, machine learning, and computer vision have not been sufficiently tested in IBCI. The second objective of this study was to assess how RS and machine learning techniques can be used to enhance the mapping of smallholder crop farming landscapes. The findings show that machine learning ensembles and the combination of optical and microwave data can map a smallholder farming landscape with a maximum accuracy of 97.71 percent. The third objective was to identify factors that influence crop yields and crop losses in order to improve IBCI design. Results demonstrated that the pervasive notion that low yields in smallholder farms are related to rainfall is an oversimplification. Factors including fertilizer use, seed variety, soil properties, soil moisture, growing degree-days, management, and socioeconomic conditions are some of the most important factors influencing crop yields and crop losses in smallholder farming systems. This shows why IBCI needs to be part of a comprehensive risk management system that understands and approaches smallholder crop farming as complex by linking insurance with advisories and input supplies. Improved inputs and good farming practices could reduce the influence of non-weather factors on crop losses, and thereby reduce basis risk in weather-based index insurance (WII) contracts. The fourth objective of this study was to assess how well the combination of synthetic aperture radar (SAR) and optical indices estimate soil moisture. As stated earlier, soil moisture was found to be one of the most important factors affecting crop yields. Although this method better estimated soil moisture over the first half of the growing season, estimation accuracies were comparable to those found in studies that had used similar datasets (RMSE = 0.043 m3 m-3, MAE = 0.034 m3 m- 3). Further interrogation of interaction effects between the variables used in this study and consideration of other factors that affect SAR backscatter could improve the method. More importantly, incorporating high-resolution satellite-based monitoring of soil moisture into IBCI could potentially reduce basis risk. The fifth objective of this study was to develop an IBCI for smallholder crop farming systems. The proposed IBCI scheme covers maize and derives index thresholds from crop water requirements and satellite-based rainfall estimates. It covers rainfall deficits over the vegetative, mid-season, and late-season stages of maize growth. The key contribution of this system is the derivation of index thresholds from CWR and site-specific rainfall conditions. The widely used approach, which calibrates IBCI by correlating yields and rainfall, exposes contracts to basis risk because, by simply correlating yield and rainfall data, it overlooks the influence of non-weather factors on crop yields and losses. The proposed system must be linked or bundled with non-weather variables that affect crop yields. Effectively, this means that the insurance must be linked or bundled with advisories and input supplies to address the influence of non-weather factors on crop losses. This system also incorporates a crop area-mapping component, which was found to be lacking in many IBCI systems. In conclusion, an IBCI that is based on crop water requirements, which incorporates crop area mapping and links insurance with non-weather crop yield-determining factors, is potentially capable of improving crop insurance for smallholder farming systems. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Masiza, Wonga https://orcid.org/0000-0002-6224-3812
- Date: 2021-10
- Subjects: Precision farming , Agricultural engineering , Climatic changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23000 , vital:54890
- Description: Crop farming in Sub-Saharan Africa (SSA) is largely practiced by resource-poor farmers under rain-fed and unpredictable weather conditions. Since agriculture is the mainstay of SSA’s economy, the lack of improved and adapted agricultural technologies in this region sets back economic development and the fight against poverty. Overcoming this constraint and achieving the sustainable development goal to end poverty, requires innovative tools that can be used for weather risk management. One tool that has been gaining momentum recently is index-based crop insurance (IBCI). Since the launch of the first IBCI program in Africa around 2005, the number of IBCI programs has increased. Unfortunately, these programs are constrained by poor product design, basis risk, and low uptake of contracts. When these issues were first pointed-out in the earliest IBCI programs, many reports suggested satellite remote sensing (RS) as a viable solution. Hence, the first objective of this study was to assess how RS has been used in IBCI, the challenges RS faces, and potential contributions of RS that have not yet been meaningfully exploited. The literature shows that IBCI programs are increasingly adopting RS. RS has improved demarcation of unit areas of insurance and enabled IBCI to reach inaccessible areas that do not have sufficient meteorological infrastructure. However, the literature also shows that IBCI is still tainted by basis risk, which emanates from poor contract designs, the influence of non-weather factors on crop yields, imperfect correlations between satellite-based indices and crop yields, and the lack of historical data for calibration. Although IBCI reports cover vegetation and crop health monitoring, few to none cover crop type and crop area mapping. Furthermore, areas including high-resolution mapping, data fusion, microwave RS, machine learning, and computer vision have not been sufficiently tested in IBCI. The second objective of this study was to assess how RS and machine learning techniques can be used to enhance the mapping of smallholder crop farming landscapes. The findings show that machine learning ensembles and the combination of optical and microwave data can map a smallholder farming landscape with a maximum accuracy of 97.71 percent. The third objective was to identify factors that influence crop yields and crop losses in order to improve IBCI design. Results demonstrated that the pervasive notion that low yields in smallholder farms are related to rainfall is an oversimplification. Factors including fertilizer use, seed variety, soil properties, soil moisture, growing degree-days, management, and socioeconomic conditions are some of the most important factors influencing crop yields and crop losses in smallholder farming systems. This shows why IBCI needs to be part of a comprehensive risk management system that understands and approaches smallholder crop farming as complex by linking insurance with advisories and input supplies. Improved inputs and good farming practices could reduce the influence of non-weather factors on crop losses, and thereby reduce basis risk in weather-based index insurance (WII) contracts. The fourth objective of this study was to assess how well the combination of synthetic aperture radar (SAR) and optical indices estimate soil moisture. As stated earlier, soil moisture was found to be one of the most important factors affecting crop yields. Although this method better estimated soil moisture over the first half of the growing season, estimation accuracies were comparable to those found in studies that had used similar datasets (RMSE = 0.043 m3 m-3, MAE = 0.034 m3 m- 3). Further interrogation of interaction effects between the variables used in this study and consideration of other factors that affect SAR backscatter could improve the method. More importantly, incorporating high-resolution satellite-based monitoring of soil moisture into IBCI could potentially reduce basis risk. The fifth objective of this study was to develop an IBCI for smallholder crop farming systems. The proposed IBCI scheme covers maize and derives index thresholds from crop water requirements and satellite-based rainfall estimates. It covers rainfall deficits over the vegetative, mid-season, and late-season stages of maize growth. The key contribution of this system is the derivation of index thresholds from CWR and site-specific rainfall conditions. The widely used approach, which calibrates IBCI by correlating yields and rainfall, exposes contracts to basis risk because, by simply correlating yield and rainfall data, it overlooks the influence of non-weather factors on crop yields and losses. The proposed system must be linked or bundled with non-weather variables that affect crop yields. Effectively, this means that the insurance must be linked or bundled with advisories and input supplies to address the influence of non-weather factors on crop losses. This system also incorporates a crop area-mapping component, which was found to be lacking in many IBCI systems. In conclusion, an IBCI that is based on crop water requirements, which incorporates crop area mapping and links insurance with non-weather crop yield-determining factors, is potentially capable of improving crop insurance for smallholder farming systems. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-10
Coastal urban climate change adaptation and disaster risk reduction assessment: the case of East London city, South Africa
- Busayo, Emmanuel Tolulope https://orcid.org/ 0000-0002-9274-2145
- Authors: Busayo, Emmanuel Tolulope https://orcid.org/ 0000-0002-9274-2145
- Date: 2021-05
- Subjects: Climate change mitigation , Climatic changes , Emergency management
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/20938 , vital:46756
- Description: The increasing incidences of climate change and its registered negative effects have disturbed the entire world, with the coastal areas being the worst hit. Given the fact that coastal areas are becoming centres of global population settlement. An attempt to explore climate change-related disasters and risks is an important aspect in building communities' adaptation and resilience, especially for the most vulnerable global south. Consequently, climate change adaptation (CCA) and disaster risk reduction (DRR) have become fundamentally linked to offering sustainable solutions to address climate change and related disaster risk problems witnessed frequently in recent years. However, the assessment of synergy between CCA and DRR for coastal areas remains fragmented, vague and limited, especially for Sub-Saharan Africa and thus the need for exploration. Furthermore, the urban populace and planning stakeholders are grappling with the challenges of seeking ways to integrate adaptation measures into human livelihoods and planning systems. Also, considering complex issues inhibiting sustainable planning, for example, poor communication of climate risks affecting coastal areas, little records of hazards disclosure and disaster history, inundation and/or sea level rise etc warranted further investigation. Accordingly, the synergies between CCA and DRR in addressing various climate change-related disaster risks, especially for the coastal areas and cities was explored in this study. To this end, given the complexity of CCA and DRR, trio-theories were adopted, which included Resilience Theory (RT), Social Vulnerability Theory (SVT) and Protective Motivation Theory (PMT) as the study’s theoretical underpinnings using East London Coastal City as a case study. Consequently, a multi-method approach was employed using a review of literature, bibliometric analysis, field survey, geographic information system (GIS), and remote sensing. The first objective reveals that there is a need for convergence and harmonisation of CCA and DRR policy, programme, and practice to improve sustainable planning outcomes. Accordingly, the study proposed the adoption of a problem analysis model (PAM) for place function sustainability and local or community level resilience building. The second objective revealed that the Sendai framework for disaster risk reduction has not been fully operationalised at the local and global scales. However, in South Africa, there are efforts to streamline DRR across manifold sectors through the Integrated Urban Development Framework (IUDF). Therefore, disaster risk managers and climate change adaptation stakeholders at the local level need to embrace the position of the SFDRR to possibly offer sound and sustainable results to the most vulnerable. In addition, a bibliometric analysis on climate change adaptation from 1996 – 2019 highlights the need for more African countries' engagement and cross-collaboration between developing and developed countries in CCA research to advance sustainable solutions and improve resilience. The third objective revealed the need for more awareness, flexibility, and adaptability among stakeholders at various levels as fundamental ingredients for CCA and DRR sustainable planning outcomes. The fourth objective highlighted that floods were recorded as the most predominant hydro-meteorological hazard (n=118, 81.9percent) in the East London, coastal city. Finally, the fifth objective portrayed that many communities, populace, buildings (types), and areas are exposed to flood disaster risks, especially, communities such as Nahoon Park Valley, Sunrise on Sea, Beacon Bay, Buffalo, Gonubie, and East London are among the most vulnerable. The study recommends that early action and warning systems should be adopted, and allocation proper building codes to boost awareness to reduce the potential flood disaster risks. Moreover, the study reveals the significance of local flood disaster risk mapping in advancing CCA and DRR to ensure the implementation of coherent spatial planning for sustainable planning outcomes. The overall lessons learnt from this study are vital in contributing to the attainment of the sustainable development goals (SDGs) such as goal 11: sustainable cities and communities, and goal 13: climate action, including the seven targets and four priorities for action of the Sendai framework at a local level. The study results are deemed critical in guiding city planners, decision-makers, disaster risk managers, local communities among others towards the development of a more resilient coastal community. In general, the study calls for the integration of CCA and DRR initiatives to be premised on PAM for sustainable planning outcomes to achieve sustainable development goals and reduction of fatalities from climate-related disasters. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-05
- Authors: Busayo, Emmanuel Tolulope https://orcid.org/ 0000-0002-9274-2145
- Date: 2021-05
- Subjects: Climate change mitigation , Climatic changes , Emergency management
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/20938 , vital:46756
- Description: The increasing incidences of climate change and its registered negative effects have disturbed the entire world, with the coastal areas being the worst hit. Given the fact that coastal areas are becoming centres of global population settlement. An attempt to explore climate change-related disasters and risks is an important aspect in building communities' adaptation and resilience, especially for the most vulnerable global south. Consequently, climate change adaptation (CCA) and disaster risk reduction (DRR) have become fundamentally linked to offering sustainable solutions to address climate change and related disaster risk problems witnessed frequently in recent years. However, the assessment of synergy between CCA and DRR for coastal areas remains fragmented, vague and limited, especially for Sub-Saharan Africa and thus the need for exploration. Furthermore, the urban populace and planning stakeholders are grappling with the challenges of seeking ways to integrate adaptation measures into human livelihoods and planning systems. Also, considering complex issues inhibiting sustainable planning, for example, poor communication of climate risks affecting coastal areas, little records of hazards disclosure and disaster history, inundation and/or sea level rise etc warranted further investigation. Accordingly, the synergies between CCA and DRR in addressing various climate change-related disaster risks, especially for the coastal areas and cities was explored in this study. To this end, given the complexity of CCA and DRR, trio-theories were adopted, which included Resilience Theory (RT), Social Vulnerability Theory (SVT) and Protective Motivation Theory (PMT) as the study’s theoretical underpinnings using East London Coastal City as a case study. Consequently, a multi-method approach was employed using a review of literature, bibliometric analysis, field survey, geographic information system (GIS), and remote sensing. The first objective reveals that there is a need for convergence and harmonisation of CCA and DRR policy, programme, and practice to improve sustainable planning outcomes. Accordingly, the study proposed the adoption of a problem analysis model (PAM) for place function sustainability and local or community level resilience building. The second objective revealed that the Sendai framework for disaster risk reduction has not been fully operationalised at the local and global scales. However, in South Africa, there are efforts to streamline DRR across manifold sectors through the Integrated Urban Development Framework (IUDF). Therefore, disaster risk managers and climate change adaptation stakeholders at the local level need to embrace the position of the SFDRR to possibly offer sound and sustainable results to the most vulnerable. In addition, a bibliometric analysis on climate change adaptation from 1996 – 2019 highlights the need for more African countries' engagement and cross-collaboration between developing and developed countries in CCA research to advance sustainable solutions and improve resilience. The third objective revealed the need for more awareness, flexibility, and adaptability among stakeholders at various levels as fundamental ingredients for CCA and DRR sustainable planning outcomes. The fourth objective highlighted that floods were recorded as the most predominant hydro-meteorological hazard (n=118, 81.9percent) in the East London, coastal city. Finally, the fifth objective portrayed that many communities, populace, buildings (types), and areas are exposed to flood disaster risks, especially, communities such as Nahoon Park Valley, Sunrise on Sea, Beacon Bay, Buffalo, Gonubie, and East London are among the most vulnerable. The study recommends that early action and warning systems should be adopted, and allocation proper building codes to boost awareness to reduce the potential flood disaster risks. Moreover, the study reveals the significance of local flood disaster risk mapping in advancing CCA and DRR to ensure the implementation of coherent spatial planning for sustainable planning outcomes. The overall lessons learnt from this study are vital in contributing to the attainment of the sustainable development goals (SDGs) such as goal 11: sustainable cities and communities, and goal 13: climate action, including the seven targets and four priorities for action of the Sendai framework at a local level. The study results are deemed critical in guiding city planners, decision-makers, disaster risk managers, local communities among others towards the development of a more resilient coastal community. In general, the study calls for the integration of CCA and DRR initiatives to be premised on PAM for sustainable planning outcomes to achieve sustainable development goals and reduction of fatalities from climate-related disasters. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-05
Monitoring the impact of deforestation on an aquatic ecosystem using remote sensing: a case study of the Mngazana mangrove forest in the eastern cape province.
- Authors: Madasa, Akhona
- Date: 2020-12
- Subjects: Remote sensing , Mangrove forests , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20815 , vital:46598
- Description: Coastal mangrove vegetation at Mngazana continues to be threatened and reduced periodically due to unmonitored harvesting. Covering an area of 148ha, the Mngazana mangrove forest remains unreserved, thus, research on the Mngazana mangroves is essential in order to monitor their state and sustainable management. Since in-situ monitoring of mangrove areas is both challenging and time-consuming, remote sensing technologies have been used to monitor these ecosystems. This study was carried out to monitor the impact of deforestation using ASTER satellite images over ten years: from 2008 - 2018. Validation was carried out by comparing classification results with the ground-referenced data, which yielded satisfactory agreement, with an overall accuracy of 94.64 percent and Kappa coefficient of 0.93 for 2008; and in 2009, the overall accuracy was 88.62 percent and a Kappa coefficient of 0.85. While the overall accuracy of 95.08 percent and a Kappa coefficient of 0.92 for 2016 and 2018 were observed, the overall accuracy of 93.58 percent and a Kappa coefficient of 0.91 was yielded. NDVI and SAVI indices were used as monitoring indicators. The results obtained in the study indicated that the canopy density of the mangrove forest remained unchanged in the years under investigation. However, insignificant changes in canopy density were identified between 2009 and 2016. , Thesis (MSc) (Applied Remote Sensing & GIS) -- University of Fort Hare, 2021
- Full Text:
- Date Issued: 2020-12
- Authors: Madasa, Akhona
- Date: 2020-12
- Subjects: Remote sensing , Mangrove forests , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20815 , vital:46598
- Description: Coastal mangrove vegetation at Mngazana continues to be threatened and reduced periodically due to unmonitored harvesting. Covering an area of 148ha, the Mngazana mangrove forest remains unreserved, thus, research on the Mngazana mangroves is essential in order to monitor their state and sustainable management. Since in-situ monitoring of mangrove areas is both challenging and time-consuming, remote sensing technologies have been used to monitor these ecosystems. This study was carried out to monitor the impact of deforestation using ASTER satellite images over ten years: from 2008 - 2018. Validation was carried out by comparing classification results with the ground-referenced data, which yielded satisfactory agreement, with an overall accuracy of 94.64 percent and Kappa coefficient of 0.93 for 2008; and in 2009, the overall accuracy was 88.62 percent and a Kappa coefficient of 0.85. While the overall accuracy of 95.08 percent and a Kappa coefficient of 0.92 for 2016 and 2018 were observed, the overall accuracy of 93.58 percent and a Kappa coefficient of 0.91 was yielded. NDVI and SAVI indices were used as monitoring indicators. The results obtained in the study indicated that the canopy density of the mangrove forest remained unchanged in the years under investigation. However, insignificant changes in canopy density were identified between 2009 and 2016. , Thesis (MSc) (Applied Remote Sensing & GIS) -- University of Fort Hare, 2021
- Full Text:
- Date Issued: 2020-12
Assessment of the human health implications of climate variability in East London, Eastern Cape, South Africa
- Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Authors: Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Date: 2018-05
- Subjects: Climatic changes , Global temperature changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/25360 , vital:64224
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03percent and 0.9percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period. , Thesis (PhD) -- Faculty of Science and Agriculture, 2018
- Full Text:
- Date Issued: 2018-05
- Authors: Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Date: 2018-05
- Subjects: Climatic changes , Global temperature changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/25360 , vital:64224
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03percent and 0.9percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period. , Thesis (PhD) -- Faculty of Science and Agriculture, 2018
- Full Text:
- Date Issued: 2018-05
An exploratory study of the impacts of climate variability on food production availability and access in Chivi district 6, Zimbabwe
- Authors: Gwindi, Raphael
- Date: 2013
- Subjects: Climatic changes , Food security , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26696 , vital:65852
- Description: The impacts of climate variability have been of global concern for many years. These impacts are affecting economic, social, cultural, agricultural, health and political structures in different countries. Although the impacts of climate variability on agricultural production are being experienced globally, it is generally accepted that developing countries are the worst affected due to a variety of reasons. Given the high susceptibility of developing countries to climate variability, this study maps and analyses the impacts of climate variability on agricultural production, food production, availability and access in Chivi District, Zimbabwe. The study aimed at finding out experiences, so it used a qualitative approach. The study uses in-depth and focus group discussions to collect data. Chivi district is experiencing erratic weather patterns which are impacting agricultural production in general and food production in particular. Consequently, food availability and access is on the decline in the district. Even though smallholder farmers have devised coping and adaptation strategies, this is not sufficient to help them fully deal with the impacts of climate variability. This is due to their limited assets, inadequate technology and climate information among other things. In an attempt to assist these smallholder farmers cope and adapt to the impacts of climate variability, NGOs and Government Departments have instituted a number of community interventions. This assistance includes agricultural extension services, farming input support and provision of climate change information and a lot of other things. In view of these findings, the study recommends the universal adoption and growing of small grain drought resistant crops in climate variability affected Chivi. It further recommends that farmers adopt conservation agriculture, get into partnerships and co-operatives to practice irrigation gardening where those without water sources provide equipment, labour and knowledge. The study also recommends that more climate science research be conducted in Zimbabwe by both NGOs and Government Departments. Furthermore, government and NGOs should provide more support for farmers in the form of climate change related training, knowledge and technology transfer among other things. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2013
- Full Text:
- Date Issued: 2013
- Authors: Gwindi, Raphael
- Date: 2013
- Subjects: Climatic changes , Food security , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26696 , vital:65852
- Description: The impacts of climate variability have been of global concern for many years. These impacts are affecting economic, social, cultural, agricultural, health and political structures in different countries. Although the impacts of climate variability on agricultural production are being experienced globally, it is generally accepted that developing countries are the worst affected due to a variety of reasons. Given the high susceptibility of developing countries to climate variability, this study maps and analyses the impacts of climate variability on agricultural production, food production, availability and access in Chivi District, Zimbabwe. The study aimed at finding out experiences, so it used a qualitative approach. The study uses in-depth and focus group discussions to collect data. Chivi district is experiencing erratic weather patterns which are impacting agricultural production in general and food production in particular. Consequently, food availability and access is on the decline in the district. Even though smallholder farmers have devised coping and adaptation strategies, this is not sufficient to help them fully deal with the impacts of climate variability. This is due to their limited assets, inadequate technology and climate information among other things. In an attempt to assist these smallholder farmers cope and adapt to the impacts of climate variability, NGOs and Government Departments have instituted a number of community interventions. This assistance includes agricultural extension services, farming input support and provision of climate change information and a lot of other things. In view of these findings, the study recommends the universal adoption and growing of small grain drought resistant crops in climate variability affected Chivi. It further recommends that farmers adopt conservation agriculture, get into partnerships and co-operatives to practice irrigation gardening where those without water sources provide equipment, labour and knowledge. The study also recommends that more climate science research be conducted in Zimbabwe by both NGOs and Government Departments. Furthermore, government and NGOs should provide more support for farmers in the form of climate change related training, knowledge and technology transfer among other things. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2013
- Full Text:
- Date Issued: 2013
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