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Hydraulic vulnerability of Subtropical Thicket to drought : a remote sensing and physiological perspective

  • Authors: Buttner, Daniel Harry
  • Date: 2022-04
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55455 , vital:52017
  • Description: Water availability is one of largest constraints on plant survival, growth, and species distribution globally. The recent escalation in tree mortality coupled with declining precipitation and amplified temperatures has implicated drought as a major cause behind many large-scale dieback events observed across the world. Raising the question, what makes some species more resistant and persist while others dwindle and vanish from the landscape? The observed variability in species drought susceptibility demonstrates the complexity of physiological responses of plants to changes in water availability. Hydraulic dysfunction in plants has been purported to be the key mechanism behind drought-induced mortality provoking interest in hydraulic traits and critical thresholds of xylem physiological function. The capability of species to maintain hydraulic functionality under drought strongly influences the survival and general productivity towards water deficits. Hence, two core objectives, and subsequently aims, of this thesis are firstly to investigate the effect of drought on Subtropical Thicket vegetation health and productivity, and secondly to examine the underpinning physiological mechanisms and functional thresholds relaying speciesspecific drought vulnerability within this semi-arid biome. In first data chapter, this thesis offers an assessment of vegetation change under drought and its influence on plant physiological function and productivity across a subsection of Subtropical Thicket distribution. Additionally, this chapter provides a regional scale perspective of drought on Subtropical Thicket flora in the Eastern Cape of South Africa. A severe anomalous dieback event, which coincided with extreme, accumulative drought conditions was observed in 2020. Employing a combination of field-based approaches and remote sensing, this chapter aimed to provide a comprehensive report of the extent and severity of crown defoliation and canopy dieback following this event, additionally describing predisposing and compounding factors. Based on Standardized Precipitation Evapotranspiration and Standardized Precipitation Indices this event began in 2015 and coincided with amplified temperatures, exacerbating evaporative demand. Aerial UAV surveys and field-based investigations were undertaken. Remotely sensed (RS) indices provided an avenue for extensive spatiotemporal investigations to uncover the extent of drought-related impact on vegetation productivity and discuss potential underpinning mechanisms behind drought-induced mortality in Subtropical Thicket. Leveraging long-term time series RS data, Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), from Moderate Resolution Imaging Spectroradiometer (MODIS) satellites as a proxy vegetation physiological status in combination with SPI and SPEI describing drought condition and groundbased surveying defining canopy vitality condition this study incidentally addressed the aim of endeavoring to link drought-induced mortality and early warning symptoms observed in the field with RS time series data to describe drought impacts across Subtropical Thicket. Furthermore, the findings of this chapter demonstrate the spatial and temporal heterogeneity in drought impacts on Subtropical Thicket. The recent drought of 2015 till 2021 is the longest documented period for the past 50 years in which there has been no accumulated net positive water availability, this apparently perpetual state of water deficiency has enacted a high cost for vegetation productivity and growth for the study area, exhibited well by average NDVI values of less than -0.5 for over 70% of the research site. The findings of this chapter report, to the contrary of anecdotal suggestions in the literature, on the intrinsic tolerance of Subtropical Thicket and that ii drought has a far more significant role on overall vegetation productivity, growth, and mortality in this region. The second data chapter assess whole-plant physiological functionality during a drought event in the Eastern Cape, South Africa. This is the first study in Subtropical Thicket to quantify in situ hydraulic functional integrity under a natural drought event testing the leading hypothesis describing tree mortality – hydraulic dysfunction. This chapter firstly, investigates hydraulic traits (e.g., turgor loss point) and describe key physiological thresholds (e.g., P50) for maintaining function during drought. Secondly, levels of native embolism were determined under drought conditions and combined with measurements of xylem vulnerability to embolism providing an estimation of degree of hydraulic dysfunction experienced by six dominant woody canopy species in Subtropical Thicket – to quantify interspecific drought tolerance and susceptibility. Subtropical Thicket species exhibited remarkable tolerance towards desiccation (TLP from as low as -3MPa) and hydraulic functional resistance to embolism (P50 value as low as -7.89MPa). The observed unexpected drought resilience of subtropical derived lineages highlights the intrinsic evolutionary role aridification had, selecting for greater embolism resistance and community-level conservatism in drought resistance of Subtropical Thicket. The level of native embolism and hydraulic safety margins identified two species (Schotia latifolia and Polyagla myrtifolia) that were the most vulnerable, and a third (Pappea capensis) moderately vulnerable, then the remaining studied species – this could result in community-level adjustments in species composition and structure under future projected climate change scenarios where, increased frequencies of drought events are anticipated. This retrospective assessment of canopy vigor with physiological functional thresholds evokes hydraulic dysfunction as the principal mechanism of observed Subtropical Thicket dieback to drought. This chapter provides crucial in situ data for predictive assertions around drought-induced mortality risk in a phylogenetically diverse and climatically unique biome of southern Africa; and is the first to identify critical hydraulic thresholds for tree species within this region. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

Impacts of algal blooms in a temperate Estuarine fish nursery area, South Africa

  • Authors: Bornman, Eugin
  • Date: 2022-04
  • Subjects: Cyanobacterial toxins --Environmental aspects , Estuarine eutrophication --South Africa
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/55899 , vital:54398
  • Description: Anthropogenically-derived eutrophication and Harmful Algal Blooms (HABs) are an increasing threat to estuarine ecosystems globally. The rapid population growth in coastal areas and the mismanagement of water resources have led to the rapid increase in eutrophication in estuaries. Consequently, HABs have become frequent phenomena with severe impacts on the ecological functioning of these systems. A paucity exists in understanding the specific mechanisms of how HABs impact estuarine communities globally. This has not been studied in South Africa, despite the observed increase in the occurrence of HABs in the past few decades. Therefore, this study investigated the impact of HABs on the ecological functioning of the anthropogenically altered Sundays Estuary, South Africa, which is affected by predictable and recurrent HABs of the raphidophyte, Heterosigma akashiwo. This study found that a high density (> 1000 cell m L-1 ) of H. akashiwo was present during all but the winter months in the poly- to mesohaline zone, yet it peaked in warmer spring/summer months with a density of ca. 70 000 cell m L-1 corresponding to 800 µg Chl-a L -1 . This species significantly altered the estuary's water quality, causing supersaturated surface- and hypoxic bottom-water during severe HABs or referred to as hypereutrophic bloom phases (> 60 µg Chl-a L -1 ). Despite these changes, the common copepod, Pseudodiaptomus hessei, occurred at similar densities among HAB phases and responded to similar triggers to the HAB. However, a shift in predator-prey interactions within the zooplankton community was evident, with scavenger or opportunist species such as the isopod, Cirolana fluviatilis, and the polychaete, Perinereis falsovariegata, occurring at higher densities during hypereutrophic bloom phases. The overall abundance of juvenile and small adult fishes were high during HABs, but the diversity decreased during HABs. Some species, notably the Mugilidae occurred at lower densities during HABs. Mugilidae also had pronounced histological gill alterations and a lowered proportion of secondary lamellae available for gas exchange during an in situ cage experiment where fishes were isolated inside and outside the HAB. Deformities such as tumorous growths were also found for the first time in a South African Estuary. This indicated a stressed population of Mugilidae in the Sundays Estuary. The ubiquitous mugilid, Mugil cephalus, actively avoided HABs during an acoustic telemetry study, despite having a home range that overlapped the HAB area. Tagged individuals mostly occupied areas directly above the HAB in the upper mesohaline to lower oligohaline zones and only iv briefly transitioned through the HAB area to utilise the lower reaches of the estuary. Since the formation of HABs is reliant on various factors, including specific species responses, environmental variables, nutrient enrichment, and flow characteristics, the impacts of HABs on estuarine communities may vary between estuarine systems or affected species. Therefore, more research that focuses on the impacts of HABs on estuaries is needed to limit the potential loss of ecosystem services. Particularly in light of further unsustainable development, upstream freshwater abstraction and climate change, will cause more frequent and severe HABs, that may result in fish population declines in the long-term. Better management and mitigation strategies are needed to reduce HAB formation such as reducing nutrient enrichment and restoring natural freshwater flow and flooding events to the Sundays Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

Phytochemical investigation and antidiabetic activity of cissampelos capensis and strychnos henningsii the Eastern Cape medicinal plants

  • Authors: Latolla, Nehemiah Solomon
  • Date: 2022-04
  • Subjects: Medicinal plants -- Eastern Cape (South Africa) , Endemic plants -- South Africa
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/56145 , vital:55956
  • Description: Diabetes mellitus is recorded as a significant health crisis in South Africa and various medicinal plants are used for the management of diabetes. However, the chemistry and bioactivity associated with these plants' antidiabetic activity are still lacking. Cissampelos capensis L.f. and Strychnos henningsii Gilg are among the plants utilised to manage diabetes in the Eastern Cape Province, South Africa. C. capensis and S. henningsii are known for their isoquinoline – and indole alkaloids, respectively. Other phytochemical groups associated with antidiabetic activity are the phenols, flavonoids, and terpenes. Thus, this study aimed to evaluate in-depth the phytochemical profiling, alkaloidal identification, and structural characterisation of phytochemicals isolated from these plants. Also, subsequent in vitro antidiabetic screening of the crude extracts and isolated compounds from both plants was done. The phytochemical profiling was performed by employing a qualitative and quantitative approach through high-performance thin layer chromatography (HPTLC) and UV-spectrometry. Further analysis for the identification of alkaloids was done by using LCMS. Fractionation and purification of crude extracts were achieved through crystallisation and various chromatographic techniques. NMR, HRMS, UV/Vis, FTIR, and XRD spectroscopic techniques were used to characterise isolated compounds. In vitro antidiabetic activity screening involved the investigation of cytotoxicity, antioxidant activity, alpha-amylase – and/or alpha-glucosidase inhibition (particular to type II diabetes). C. capensis and S. henningsii extracts tested positive for alkaloids, phenolics, flavonoids, and terpenes through HPTLC screening. Quantitative estimation by UV spectrometry of these phytochemical groups detected the highest concentration of alkaloids, followed by flavonoids, phenolics, and terpenes content. The in vitro antidiabetic biological screening of the various crude extracts suggested that the presence of alkaloids, flavonoids, phenolics, and terpenes fostered favourable biological activity. The LCMS of the known alkaloidal constituents from C. capensis detected the presence of ten alkaloids, including glaziovine, lauroscholtzine, pronuciferine and vi salutardine. Seven known alkaloids and one triterpene were detected from S. henningsii, including holtsiine, 23-hdroxyspermostrychnine, henningsiine, and the triterpene, friedelin. These findings suggest that C. capensis and S. henningsii have similar phytochemical constituents compared to the species reported in literature. However, the distribution of the phytochemicals in the various plant parts differed from previous accounts. , Thesis (PhD) -- Faculty of Science,School of Biomecular and Chemical Sciences , 2022
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  • Date Issued: 2022-04

Potential suppressive effects of alien Acacia melanoxylon on Afrotemperate Forest tree recruitment

  • Authors: Miles, Bayleigh , Baard, Johan
  • Date: 2022-04
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55391 , vital:51989
  • Description: Acacia melanoxylon R.Br. is a prominent alien and invasive species in many parts of the world and evidence exists of its adverse effects on indigenous forest community composition through allelopathy and alteration of light regimes. The species also occurs extensively in Southern Cape Afrotemperate Forest (South Africa) and is thought to suppress indigenous Afrotemperate Forest tree seedlings through various mechanisms such as the alteration of natural light regimes or allelopathy, although this has not been rigorously verified. This study aimed to investigate whether Acacia melanoxylon has a suppressive effect on Afrotemperate Forest tree recruitment. Firstly, we assessed the potential allelopathic effect of Acacia melanoxylon and an indigenous Afrotemperate Forest species Olea capensis macrocarpa (C.H.Wright) I.Verd. on the germination of Acacia melanoxylon and three prominent indigenous tree species’ seedlings in a nursery trial. Germination of the indigenous species failed; however, we were able to compare the germination of Acacia melanoxylon among the three treatments, namely Acacia melanoxylon leachate, Olea capensis leachate, and no leachate. The average germination of Acacia melanoxylon was 67% and germination was marginally higher under Acacia melanoxylon leachate and Olea capensis leachate, respectively, than under the control. This suggested that germination of the species is improved, or at the least, unaffected, by leachates of itself or that of a common indigenous canopy species. We then critically evaluated the germination requirements of the indigenous test species to determine probable reasons why their germination failed in our trial. The most plausible explanation for the germination failure could be that the trial period did not encompass an entire winter season and may not have provided adequate cold stratification. We concluded that the lack of sensitivity of Acacia melanoxylon to leachates of itself or a common indigenous overstorey species likely contribute to its success as an invasive species in Southern Cape Afrotemperate Forest. Secondly, we investigated, through field surveys, whether Acacia melanoxylon affects indigenous Afrotemperate Forest tree sapling composition and light regimes underneath its canopy. Using a paired plot design, we compared light intensity, tree sapling species richness, diversity, and density underneath 30 overstorey Acacia melanoxylon trees and 30 indigenous counterparts. We recorded 2506 indigenous tree saplings from 29 species in the 60 plots and found that there were no significant differences in richness, diversity, or v density of saplings underneath Acacia melanoxylon compared to that under indigenous counterparts. Light intensity did not differ significantly underneath Acacia melanoxylon and indigenous canopies, however light intensity varied significantly more underneath the canopies of Acacia melanoxylon. Canonical correspondence analysis of the abundance of sapling species confirmed that sapling composition was not largely determined by the overstorey species. We concluded that Acacia melanoxylon does not significantly alter indigenous tree species composition underneath its canopy at the typical densities (<3 trees per hectare) at which it occurred in the forests of the Garden Route National Park that we surveyed. Nevertheless, populations of Acacia melanoxylon in the forest interior still act as a source of propagules for invasion in forest margins, riparian areas, and neighbouring fynbos shrubland. These invasive attributes need to be considered in the management of the species in the region at large. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2022
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  • Date Issued: 2022-04

Refining predator-prey preference at the prey demographic level for cheetah and lion

  • Authors: Annear, Eleesha
  • Date: 2022-04
  • Subjects: Social behavior in animals --South Africa , Predatory animals –Behavior
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55800 , vital:53880
  • Description: Traditional prey preference models estimate prey preference using a coarse species-specific body mass of three-quarters of the mean adult female body mass. This is widely assumed to estimate the average mass across prey populations, accounting for neonates, juveniles, sub-adults, and adults. However, this approach negates the models’ ability to predict demography-specific prey preferences, thus reducing our ability to predict the impacts of predation on prey populations. The objectives of this study were to 1) refine the prey selection models, using lion Panthera leo and cheetah Acinonyx jubatus as model species, by incorporating prey demographic classes and season and, 2) determine the influence of seasonal variability in availability of these prey demographic classes on cheetah reproduction. Lions preferentially killed adults of larger species (e.g., wildebeest, waterbuck, and zebra) irrespective of the season, as predicted by optimal foraging theory. Sub-adult, juvenile, and neonate prey were killed by lions relative to their abundance. Cheetahs preferred juvenile prey of large species, namely kudu, zebra, and wildebeest. Season influenced cheetah preference with neonates and juveniles being preferred during the wet season and adults of smaller species, and juveniles of larger species being preferred during the dry season. Thus, results support the alternative demographic class hypothesis. Furthermore, the availability of neonate and juvenile prey drives cheetah reproduction patterns with conception and cub independence coinciding with the peak availability of easy-to-catch neonates. Lactation coincided with the high availability of relatively larger juveniles to ensure that females obtain enough resources to sustain the most energetically costly reproductive phase. In addition, I suggest cheetah may be particularly vulnerable to disturbances that impact on prey reproduction (e.g., drought, fire, and flood), given their reliance on neonate and juvenile prey. My findings highlight that estimating species-level prey preference using a coarse species-specific body mass masks the level of prey use and potential preferences for the different prey demographic classes. The use of some prey species may be largely confined to juveniles by smaller predators, meaning that prey availability would vary seasonally, may influence reproductive patterns, and carrying capacity models would need to be revised in terms of the available demographic-specific prey biomass. , Thesis (MSc) -- Faculty of Sciences, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

Seasonal changes of metals in the salt marsh and seagrass beds of the Swartkops Estuary

  • Authors: Nel, Marelé Annette
  • Date: 2022-04
  • Subjects: Salt marshes--Effect of heavy metals on--South Africa--Swartkops River Estuary , Estuarine ecology --South Africa --Swartkops River Estuary
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55734 , vital:53411
  • Description: Estuaries are historically convenient places to build industries, as it was deemed a suitable place to dispose of large quantities of urban and industrial waste into the ocean. At the time it was judged to be appropriate, as rivers can transport and deposit waste into the ocean, which was considered so vast that it is insurmountable. Therefore, metal pollution in estuaries is a well-known occurrence. Coastal wetlands play an important role in the cycling of metals, and act as effective metal sinks. They provide an important ecosystem service acting as accumulators and phytostabilisers, which make toxic levels of the metals unavailable to the rest of the food chain. The overall aim of this study was to assess the metal pollution in the salt marsh (Salicornia tegetaria and Spartina maritima) and seagrass (Zostera capensis) of the heavily developed Swartkops Estuary. Assessing the metals in the estuary will provide information on effective environmental management strategies. Metal concentrations were measured in the rhizosediment of the three wetland plants, bare sediment, and in the tissues (leaves, shoots, and roots) of the selected plant species. Sampling occurred during one seasonal cycle (2019-2020), and in 5 sites along the middle and lower reaches of the estuary. Metal concentrations were not the highest closest to the point sources in the middle reaches, but the metals rather accumulated downstream in Site 3 (Tiger Bay launch site close to the WwTW) and Site 4 (Tippers’ Creek), which were depositional sites. Although these two sites generally displayed the highest metal concentrations, they also had the most seasonal fluctuations in their metal concentrations and sediment characteristics. Flushing events in spring/summer were likely the determining factor of these fluctuations. The mouth of the estuary (Site 5) consistently had much lower metal concentrations, with distinctly more sandy, low organic content sediment, due to marine-influenced flushing. Thus, spatial differences were distinct in the estuary, however seasonal differences did not play an important role in the metal concentrations, indicating that seasonal sampling was not as important as sampling in different sites. Assessing the metal concentrations in different rhizosediment gave important insights on intertidal accumulation and contrasted with the unvegetated (bare) sediment. The metals generally accumulated more, higher up the intertidal range, due to less frequent tidal inundation and flushing — so that metal accumulated in the vegetation in the following order: Z. capensis > S. maritima > S. tegetaria. Moreover, unvegetated (bare sediment) showed much lower metal concentrations compared to the rhizosediment, indicating that the vegetation trapped small particles, and changes the physical environment to concentrate metals in their rhizosphere. Lastly, the plant species all displayed good accumulation of metals in their roots, while Z. capensis also showed remarkable uptake to its leaves. The study identified S. maritima and S. tegetaria as good phytostabilisers, particularly the latter with its vi high metal stocks and slow root turnover rate. The compartmentalization in these plants were unique to each species, corroborating previous assessments that compartmentalization cannot be compared between similar life forms and genera. These results contribute to local and international research on biogeochemistry in wetlands, and assessment of pollution in developed estuaries. Of note is Z. capensis, an endemic Southern African species, which has not been analysed for compartmentalization of metals before. All three of the studied species have potential as metal accumulators, and therefore a sink of metals. They localize the metals, limiting bioaccumulation to the rest of the food chain, which reduces the ecotoxic effect of metals in the environment. Higher accumulation in vegetated (rhizosediment) over bare sediment, make these habitats valuable metal sinks. This increases their importance in estuaries receiving high pollution loads, and they should be prioritized in conservation efforts. Two sites within the Swartkops Estuary, Tippers’ Creek (Site 4) and the Launch Site (Site 3), are potential sites for long-term monitoring due their capacity to trap and accumulate metals. The results of this study will inform local management on the state of metals in the Swartkops Estuary, providing crucial information on the importance of preserving local wetlands for the purpose of regulating toxic levels of metals in the ecosystem. , Thesis (MSc) -- Faculty of Science, Botany, 2022
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  • Date Issued: 2022-04

Smart catchment management and application in the Swartkops River and Estuary

  • Authors: Mmachaka,Thandi Nthabiseng
  • Date: 2022-04
  • Subjects: Estuarine ecology--South Africa--Swartkops River Estuary
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/55932 , vital:54401
  • Description: The influence of urbanization and industrialization on natural resources results in complex water resource management. In South Africa, there has been escalating rural-urban migration, a growing population in urban areas, and the mushrooming of informal settlements in cities over the last five decades. In the pursuit of protecting water resources, these contextual realities create a significant challenge to policymakers, planners, and implementers. Due to rapid population growth, climate change, recent droughts, and growing competition among agricultural, industrial, commercial, environmental, and domestic sectors, water resources are presently under severe stress in South Africa. This situation necessitates the effective management of water resources. This study completed a situational assessment for the Swartkops Catchment to examine the extent of pollution, mapped sources of pollution, investigated water quality governance and identified hot spot areas to provide the foundation for effective and efficient catchment management. To determine the current water quality status of the Swartkops Catchment, this current study investigated spatial and temporal variation in physico-chemical parameters, nutrients, and faecal bacteria. This study applied a mixed-method research design using semi-structured interviews and focus groups discussions as data collection methods to investigate the water quality governance of the Swartkops Catchment. Following the situational assessment of the Swartkops Catchment, the effectiveness of applying innovative smart catchment practices to improve water quality was investigated. The word smart in this context refers to innovative mechanisms that will ensure effective and efficient water resources management. The PHP scripting language (Hypertext Preprocessor), Android studio, Wampserver, and JavaScript were used to develop the Water Use Screening System (WUSS) and Pollution Incident Reporting System (PRS). In South Africa, stormwater infrastructure suffers from unsustainable utilization. Stormwater systems discharge into many of the country‘s rivers and estuaries, including Swartkops, leading to water quality degradation. To improve the Recommended Ecological Category (REC) of the Swartkops Estuary to Category C, drivers that contribute to poor water quality must be understood to inform appropriate management interventions. Results from sampling in Markman Canal were compared with historical water quality data. The present study showed that the Markman Canal contributed faecal bacteria, nutrients, and trace metals to the Swartkops Estuary. The Markman Canal was the greatest source of trace metals to the Swartkops Estuary compared to the other point sources entering the estuary. The results show that arsenic and mercury levels in the Markman Canal and the Swartkops Estuary were higher than that previously measured. Iron and copper concentrations were higher in the Markman Canal whereas only copper increased in the Swartkops Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

Spatial modelling of accessibility to tuberculosis treatment: the case of Ngaka Modiri Molema District

  • Authors: Ramotsongwa, Karabo Naome
  • Date: 2022-04
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55435 , vital:52000
  • Description: Accessibility to healthcare refers to the availability, or the provision of healthcare-byhealthcare professionals and stakeholders and individuals' ability to obtain care and treatment. It affects overall physical, social, and mental health; disease and disability prevention; detection and treatment of health conditions; standard of living; preventable death; and life expectancy, and it is crucial to the performance of health care systems around the world. If healthcare services are available and are in sufficient supply, people will be able to seek health care, and a population will have access to services. The leading cause of death globally is Tuberculosis (TB) and South Africa is amongst the top 5 countries most affected by TB. This is aggravated by high HIV/AIDS statistics. Children belowthe age of 4, between the ages of 4- 15, and women and men of working ages are highly affected by TB and it is the primary cause of death in these groups in the Ngaka Modiri Molema District. This study used study tools like Spatial Modelling, Geographic Information Systems and software like ArcGIS 10.5, TerrSet IDRISI 18.30, and secondary data from the North West Departmentof Health (Tier.net &DHIS) and also TB patients’ home addresses to investigate the accessibility of TB treatment in Ngaka Modiri Molema, in order to spatially visualize the distribution of a communicable disease like TB and public healthcare facilities in the Ngaka Modiri Molema (NMM) District and suggest optimum sites for hospital facilities. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

Synthesis and applications of novel fluorescent and colorimetric coumarin-based sensors towards analyte sensing in aqueous systems

  • Authors: Battison, Aidan Leigh
  • Date: 2022-04
  • Subjects: Water-supply engineering--Technological innovations , Polymers--Optical properties , Fluorescent polymers
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/55954 , vital:54558
  • Description: The continuous growth of mankind has not been considerate to the environment. The release of millions of tonnes of toxic heavy metal cations and anionic species through industrial, mining, agricultural, and electronic dumping has led to disease and, in many instances, death. This is usually suffered by low-income informal populations residing in third world countries. Moreover, many unnecessary deaths of children are becoming more prevalent because of consumption and contact with contaminated water, agricultural, and animal sources. Bioaccumulation of these toxic species in fish, plants, and animals, inevitably make their way back to the unaware general population. As growth by mining, agriculture, and electronics are indeed vital aspects of human development, the negative side effects of these activities usually continue unregulated. Therefore, as these processes are set to continue until more stringent regulatory processes are put into legislature; low-cost, sensitive, selective organic based sensors are a step in the right direction towards highlighting the need for environmental restoration and remediation; whilst also aiming to preventing unnecessary disease and death in the process. Herein, coumarin derived small-molecule fluorescent and colorimetric sensors for the quantitative and qualitative assessment of cationic and anionic species in aqueous and organic media are described. Ten fluorescent sensors supporting 1,4-disubstituted triazolyl moieties were synthesized according to Cu(I)-catalyzed azide-alkyne cycloaddition “click” reactions. These sensors were screened for their cationic and anionic affinities in a variety of solvent systems. Majority of the sensors responded well towards Fe3+, characterized by a strong fluorescent quenching response with a good degree of sensitivity and selectivity. Selected sensors were further investigated for their affinities towards anionic species; however, they did not display the same degree of selectivity or sensitivity towards these chosen anions. Titration studies of selected sensors with Fe3+ were able to be used towards determining the modes of fluorescent quenching; the photophysical mechanisms by which quenching occurs; stoichiometric binding ratios, association constants, and the number of coordination sites present between the sensors and Fe3+. Reversibility studies of the sensor-metal complex was investigated with EDTA. Partial reversibility was achieved for the chosen sensors with Fe3+. Hydrogen potential studies further described the application of these sensors over a good pH range. The binding site between the sensors and Fe3+ was investigated by NMR studies. , Thesis (PhD) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
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  • Date Issued: 2022-04

Synthesis of cannibigerol, an antibiotic for methycillin resistant staphylococcus aureus, in continuous flow system

  • Authors: Koeberg, Bryce
  • Date: 2022-04
  • Subjects: Drug resistance in microorganisms , Cannabis -- Therapeutic use -- South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55866 , vital:54395
  • Description: This study focuses on the development of a synthetic version of the cannabinoid cannabigerol (CBG) through continuous flow systems. The compound has exhibited antibiotic properties that have been proven to be a potent killer of gram-positive methicillin-resistant Staphylococcus aureus that drive repeat infections. The cannabinoid kills the superbug by disrupting the cell wall integrity of cells that are drug resistant. Research suggests that CBG is not effective against gram-negative multi-drug resistant bacteria. However, when CBG is administered with polymyxin B, an antibiotic that disrupts the outer membrane of gram-negative bacteria the cannabinoid compound wipes out the drug-resistant gram-negative bacteria, thus revealing the extensive medicinal potential of cannabigerol. Cannabinoids, such as CBG, are present in low yields in the plant, depending on the extraction method, usually less than 5% in most strains. Natural medicines have a low amount of active ingredients due to the lab intensive and time-consuming extraction and isolation process; this has hindered the application of natural products in drug development. A major health concern of the human consumption of cannabis plant extracted cannabinoids is that the plant may be contaminated with microbes, heavy metals and pesticides due to the lack of regulation. Thus, it is proposed that these cannabinoids are synthetically produced through the integration of microfluidic technology, eliminating the presence of pesticides, microbes and heavy metals. The proposed method would even further speed up the rate of production at a lowered cost, produce greater yields of the product compared to extraction procedures / in batch reactions and improve the purity of cannabinoid compounds. This was achieved in flow chemistry whereby the key intermediates (olivetol, a derivative of methyl 6-n-pentyl-2-hydroxy-4-oxo-cyclohex 2-ene-l-carboxylate and cannabigerol) were produced at high conversions (67%, 100% and 34% respectively) in LTF glass microreactors. Cannabigerol was successfully synthesized in flow at high yields compared to literature, however, it was further discovered that the formation of side products was a hindrance to further improvement of the obtained yield in flow. , Thesis (MSc) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
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  • Date Issued: 2022-04

The foraging ecology of female Cape fur seals (Arctocephalus pusillus pusillus) in South Africa

  • Authors: Botha, Jonathan Aubrey , Kirkman, Stephen , Lombard, Amanda
  • Date: 2022-04
  • Subjects: Seals (Animals)--Habitat—Conservation , Marine ecology—South Africa
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/55965 , vital:54559
  • Description: The marine environment is spatially and temporally dynamic and many marine ecosystems are experiencing impacts of broad-scale climate change. Within these ecosystems, marine predators play a crucial role in ecosystem function through their top-down influences on prey populations. These predators may also respond to bottom-up influences and changes at lower trophic levels. A thorough understanding of marine predator foraging ecology is thus important to improve our understanding of ecosystem function, inform conservation and management measures, and to predict the response of predators to future environmental change. The Cape fur seal (Arctocephalus pusillus pusillus) comprises a major proportion of the southern African marine predator biomass. However, little is known about the foraging distribution and behaviour of the species, despite its obvious importance within the ecosystem and increasing concerns regarding seal-fisheries conflict. Using a variety of technologies, including, GPS and satellite-linked tags, dive behaviour recorders, accelerometers and stable isotope analysis, this thesis investigated the foraging ecology of female Cape fur seals breeding on the coast of South Africa. First, to identify important foraging areas and assess the influence of geographic, temporal and environmental factors on these areas, lactating females from three breeding colonies were fitted with GPS or Argos-linked tracking devices, while individuals from two of these colonies were also fitted with dive behaviour recorders. Results revealed geographic differences in the foraging distributions and ranges of individuals between breeding colonies, which likely reflects a combined influence of ecological setting and density dependant competition. In addition, dive behaviour recorders revealed the occurrence of benthic foraging at both sites where they were deployed, and the dominance of this strategy in some individuals. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

The Impact of socio-Economic and institutional factors on the Livelihoods of artisanal fisherfolk of Korsten, Gqeberha.

  • Authors: Forbes-Liberty,Abigail
  • Date: 2022-04
  • Subjects: Fishing--Social aspects -- South Africa , Korsten-- Gqeberha
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55584 , vital:53334
  • Description: his dissertation focuses on a relatively underrepresented group of the fishing industry: subsistence fisherfolk. By using a Sustainable Livelihoods Approach (SLA) and Community Capitals Framework (CCF) as a theoretical framework and interpretive lens, the purpose of this qualitative study is to explore the impact of socio-economic and institutional factors on the livelihoods of artisanal fisherfolk of Korsten, Gqeberha (formerly known as Port Elizabeth). By highlighting the socio-spatial implications of the forced removals of the past, this dissertation shows that legislative reforms should consider the population that they affect. Food security is a major issue on a global scale and South Africa is not impervious to food security concerns. This dissertation focuses on the negative impact that socio-economic climate and legislation has had on subsistence fisherfolk. Hunger and poverty eradication is one of the key goals of sustainable development. In this case, subsistence fishers faced legislative reforms at two distinct points in its tumultuous past, both of which had a detrimental impact on this sector of society's ability to support a healthy livelihood. This research fills a theoretical and practical gap in research regarding the current livelihoods, policies, and laws, as well as provides a deeper understanding of the socio-economic context of the subsistence fishing community of Korsten, Gqeberha. The SLA and CCF helps readers understand how subsistence fishers contribute to local livelihoods and integrate into the greater processes of the community. Further, exploration of the institutional policies limiting subsistence fishers helps understand decision making processes and laws in artisanal fisheries and the implications thereof. A snowball sampling method was used to recruit and enrol participants for this study. The sample size consisted of fourteen (14) participants consisting of eight (8) subsistence fishers and six (6) relatives of subsistence fisherfolk. Narrative analysis is a qualitative method that was conducted in this study. Participant observation and semi-structured interviews were conducted as the methods of data collection and analysed in ATLAS.ti 9 Qualitative Analysis Software. Most participants indicated that fishing plays an integral part of their lives. It contributes to and still ensures the food security in the families of Korsten. In addition, participants highlighted the constant legislative and socio-economic barriers as well as the social and personal benefits of fishing in the community. A key recommendation is made for policy-makers to be cognizant of subsistence fishers and to include this underrepresented group in decision making processes. , Thesis (MSc) -- Faculty of Science, Geosciences, 2022
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  • Date Issued: 2022-04

The potential impacts of hydraulic fracturing on Khoisan peoples’ sense of place: in the case of Karoo Region, South Africa

  • Authors: Tembe, Thandeka
  • Date: 2022-04
  • Subjects: Hydraulic fracturing--Environmental aspects--South Africa--Eastern Cape , Khoikhoi (African people) -- History
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55701 , vital:53408
  • Description: Hydraulic fracturing is a practical solution to minimising production of fossil fuels and to boost the South African economy. However, this development comes at a cost to the society, environment and heritage of the Karoo, which is home to majority of the Khoisan community. Developments such as hydraulic fracturing are barely understood by local communities therefore this study tried to determine the potential impacts of hydraulic fracturing on Khoisan people’s sense of place in the Karoo region, to also establish their perceptions, attitudes, opinion and knowledge on hydraulic fracturing, to facilitate and improve understanding. A mixed method approach was employed to gather relevant information from participants. The qualitative data collection used semi structured interviews to gain participants perceptions, attitudes, opinions and knowledge on hydraulic fracturing, whereas quantitative used questionnaire survey which was administrated to gain socio-demographics and sense of place of Khoisan people (N=50) using survey based psychometric approach to examine the relationship between Khoisan people and sense of place on proposed hydraulic fracturing in the Karoo region (Cradock). Primary data was employed to gain in depth raw data directly from participants and secondary data from literature that already exists. The purposive and snowball sampling technique was used to draw Khoisan participants from the Karoo region (Cradock). Data acquired was analysed using SPSS v26 and Microsoft excel. The results concluded that most Khoisan participants (N= 43) are not aware of what hydraulic fracturing is and therefore there is a need to be taught about the development. The (N= 7) of the participants who have an idea of what hydraulic fracturing is had attended a workshop that was facilitated by the AEON research institute, others learnt about it on the internet and others were informed by someone who either learnt from the internet or attend the workshop. The study also concluded that the Khoisan people have a strong positive sense of place (α= 0.922) with the Karoo region therefore going ahead with the proposed hydraulic fracturing will cause massive damage and could possibly lead to solastalgia and loss of sense of place. vi The recommendation of the study was to involve all stakeholders who will be part of the development of hydraulic fracturing from government, research institutes to oil and gas companies to thorough research, educate and inform local communities in the Karoo. Therefore, it is essential for the government to protect the Karoo culture and heritage, local peoples sense of place by communicating with local communities on such development and assist in holding these companies reliable for any misconducts. , Thesis (MSc) -- Faculty of Science, Environmental Geography, 2022
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  • Date Issued: 2022-04

The use of psychometric test systems as a pre-selection tool for identifying successful harvesting machine operators

  • Authors: Schwegman, Kylle
  • Date: 2022-04
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/55246 , vital:51102
  • Description: A shift towards fully mechanized forest activities, such as harvesting and, more recently, silviculture, has occurred from the early 2 000’s. The reason for mechanizing these activities differs for each country, although for most countries there is concern relating to the health and safety of forest workers. With mechanization in harvesting, the forest worker has moved away from the physical intensity of having to fell, debranch, debark and cross-cut trees into logs using either an axe or chainsaw, to operating a machine. Studies revolving around the human element (operator) have been conducted specifically relating to the ergonomics of the machines and how operators may influence machine productivity. Results showed that due to the repetitive nature of the work, the operators are exposed to associated stresses for longer periods. Typical injuries associated to these kinds of stressors are whole body vibrations (WBVs), repetitive hand and arm movements, non-neutral body postures and manual lifting, which lead to musculoskeletal symptoms in the lower back, neck and shoulders. However, as machine technology improves so does the ergonomic conditions which are experienced by machine operators. Machine productivity can be influenced by various factors, with the most influential being tree volume. However, a recent study showed that over 40% of variation in machine productivity has been observed amongst different machine operators operating similar machines. The specific reason for these differences has yet to be determined. However, decision making, motivation, planning capacity, concentration, memory, motor coordination, pattern recognition, logic reasoning, and spatial perception are abilities that have been described as important for successful harvesting work. The pre-selection of operators using psychometric and cognitive tests is not new to forestry, although very little information is available relating to the aptitude test known as the Vienna test system as well as the best possible demographic associated with successful harvesting operators. The overall aim of this study was to determine whether the high variation found amongst harvesting machine operators could be reduced initially through a preselection process which involves the use of aptitude tests (Vienna Test System) and demographic questionnaires. A study was implemented in Zululand, South Africa, testing whether there were significant productivity differences between nine machine operators. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Management, 2022
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  • Date Issued: 2022-04

Using information visualization to support the self-management of type 2 diabetes mellitus

  • Authors: Nauder, Meggan Kate
  • Date: 2022-04
  • Subjects: Information visualization , Diabetics --Treatment --South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/55711 , vital:53409
  • Description: The globally increasing number of individuals suffering from Type 2 Diabetes Mellitus (T2DM), a completely preventable incurable disease of the pancreas, highlights the need for an effective tool for users to understand the relationship between their behaviours and the effect that those behaviours can have on their blood glucose levels (BGLs). There are few Information Visualisation (IV) tools available that can be used to reduce the cognition required to understand correlations between behaviour and BGLs. Existing tools require time-consuming, lengthy inputs and provide simple visualisations that do not show correlations. This leads to ineffective self-management of T2DM. Information Visualisation (IV) techniques can be used to support effective self-management of T2DM and reduce the cognition required to interpret DM data. Suitable IV techniques were identified and used to visualize T2DM data to aid in the self-management of the disease. Temporal charts, i.e. The Bar, Pie and Line Chart as well as heat maps, were selected as the most appropriate IV techniques to visualize T2DM data as they support time-series data well. A prototype, MedicMetric was created as an IV tool for visualizing T2DM data. MedicMetric incorporated three designed charts, namely the Change Rate Line View, the Radial Progress View, and the Annotated Line View. The Change Rate Line View and Annotated Line View both used line IV techniques, while the Radial Progress View made use of the bar IV technique. The Change Rate Line View performed the worst overall. A usability evaluation was conducted to compare these techniques and to determine which technique is most suitable for visualizing T2DM data. The results leaned significantly in favour of the Annotated Line View. This view is most similar to the line charts typically used in other IV tools. For this reason, the MedicMetric app was briefly compared to the MySygr and Diabetes:M application. In effectiveness and efficiency, MedicMetric and MySugr obtained almost identical results. However, participants indicated that MedicMetric supported their tasks using the Visual Information Seeking Mantra (VISM) the best overall, with 100% of participants stating that they would prefer to use the MedicMetric application. Several usability problems were identified with the IV techniques and they were addressed shortly after the study was complete. Overall participants were most satisfied with the Annotated Line View. , Thesis (MSc) -- Faculty of Science, Computing Sciences, 2022
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  • Date Issued: 2022-04

Zooplankton dynamics of Algoa Bay (South Africa) under varying oceanographic conditions

  • Authors: Bizani,Mfundo
  • Date: 2022-04
  • Subjects: Marine zooplankton -- South Africa , Climate changes
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/55943 , vital:54554
  • Description: the ecological significance of ocean plankton in terms of nutrient cycling and energy transfer is widely recognised, as is their mechanistic link with both oceanographic processes and climate. Consequently, plankton are widely regarded as sentinels of climate change, principally owing to their responsiveness to changing environmental conditions. Developing an understanding of the ecological as well as socio-economic consequences associated with changes in marine plankton dynamics has emerged as a key issue worldwide. Though many exciting advances in this respect have been attained with the aid of long-term plankton time series (>50 y), global environmental datasets and innovative meta-analyses, building deep knowledge of regional bio-physical dynamics and responses to specific perturbed states remains an essential component of the collective effort. Algoa Bay, situated on the warmtemperate south-east coast of South Africa presents a unique opportunity to study key elements of plankton ecology relevant to climate change problems in the regional sense. The embayment is locally subjected to frequent wind-driven upwelling and regionally, to periodic mesoscale oceanographic forcing (e.g., large solitary meanders, Agulhas Current intrusions), all of which culminate in a complex physical and biogeochemical environment. Using zooplankton as the focal component and drawing from a multi-year monthly dataset incorporating a bay-scale sampling framework, the present study addressed three key hypotheses pertaining to 1) drivers of spatio-temporal variability, 2) biomass rate of change over temporal scales using time-series analyses, and 3) community responses to a bay-scale biological perturbation event. Zooplankton biomass exhibited prominent seasonal patterns with bimodal peaks corresponding with near-consistent year-to-year autumn and spring blooms. Overall, the spatial trend showed no heterogeneity, though statistical significance between-station variability was noted per season. An analytical framework involving generalised additive models revealed zooplankton spatial heterogeneity in Algoa Bay to be a function of seasonal variation in a suite of physicochemical variables, including the combined effects of temperature, salinity, dissolved oxygen, total nitrogen and silicate, but not ammonium, phosphate or chlorophyll-a (as proxy for phytoplankton). Fronts (including river plumes), warm water intrusion from the Agulhas Current, and wind-driven upwelling were postulated to be key driving forces. Structural breaks analysis performed on station-specific time series revealed significant incremental increases in zooplankton biomass over time, which in turn, corresponded with a gradual decrease in thermocline depth. The most pronounced increasing effect was associated with a period (2013– 14) of amplified land-derived nutrient input and increasing harmful algal bloom (HAB) activity. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
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  • Date Issued: 2022-04

A critical exploration of the attitudes towards and knowledge of natural resource management amongst first-year Natural Resource Management students

  • Authors: Jooste, Eileen
  • Date: 2021-12
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's , text
  • Identifier: http://hdl.handle.net/10948/53666 , vital:45688
  • Description: Available literature suggests that there is a need to gain more understanding of what students’ environmental attitudes and knowledge are and how they are developed by education systems. Education, in general, plays an important role in students’ attitudes and their knowledge of the world around them. It can shape students’ awareness of their natural environment and contribute to their understanding of environmental issues. Education can also strengthen students’ critical thinking, build awareness, stimulate problem solving, and promote sustainable practices. It has the potential to empower students to address global challenges from their own diverse perspectives and prepare them to uphold the economy. Education can improve and maintain societal wellbeing and can help students to maintain the natural environment, along with achieving sustainable development. Environmental education, specifically, can play a big role in how students deal with the natural environment. The primary aim of this qualitative research study was to examine first-year students’ environmental attitudes and knowledge in the School of Natural Resource Management at the Nelson Mandela University George Campus, South Africa. First-year students’ environmental attitudes and knowledge were examined as they entered the university, and then again at the end of the first semester once they had completed a module in ecology. More specifically, at the outset of the research the objectives were (1) to establish an understanding of the baseline environmental attitudes and knowledge of first-year students who were undertaking three ecological modules being offered by the School of Natural Resource Management; (2) to assess the changes in the first-year students’ environmental attitudes and knowledge, using a post-intervention strategy; (3) to understand what type of teaching approaches were used by the lecturers teaching the ecological modules; and (4) to evaluate how the teaching approaches of the lecturers influenced the baseline environmental attitudes and knowledge of the student group. This research took place in the midst of the Corona Virus pandemic, which had significantly influenced the teaching and learning environment. Multiple education systems, including those of the Nelson Mandela University George Campus, had to rapidly transition to online teaching and learning. So, although unplanned for, this research could not ignore the rapid transition to online teaching and learning and the role it played in shaping the first-year School of Natural Resource Management students’ environmental attitudes and knowledge. It also impacted the teaching approaches of the environmental lecturers. An additional objective in response to the rapid transition to online teaching and learning was, therefore, added: (5) to understand the experiences of the first-year School of Natural Resource Management students and the three environmental lecturers who had to rapidly transition to online teaching and learning. Data was collected via questionnaires and semi-structured interviews with students and staff in the School of Natural Resource Management at Nelson Mandela University George Campus within three different natural resource management programs, namely Agriculture, Nature Conservation, and Forestry. Baseline questionnaires were conducted with 107 students for a baseline assessment as the students entered the university. An online post-intervention questionnaire was conducted with 33 of the initial group of students at the end of the semester for a post-intervention assessment. In-depth semi-structured interviews were conducted with three environmental lectures before they taught their three ecology modules in each of the programs. Additional online semi-structured interviews were also done with the same three environmental lectures after the rapid transition to online teaching and learning took place. The significant findings from this research were analyzed and discussed. This included the baseline environmental attitudes and knowledge of the student body upon arrival at the university and the changes in their environmental attitudes and knowledge after they were exposed to the ecology modules taught in each of the programs. The discussion also included the teaching approaches adopted by the environmental lecturers and the influence their teaching approaches had on the students’ environmental attitudes and knowledge. In addition, the results shed light on the experiences of students and lecturers during the rapid transition to online teaching and learning. The main conclusions reached were that the first-year School of Natural Resource Management students did not have a deep understanding of ecological concepts prior to arriving at university, but they did show a concern for the natural environment. Their lack of understanding was reduced as the students progressed with the ecology module. A greater understanding resulted in a change in students’ perspectives on the ecological module, their program, and the industry they were preparing to enter after being exposed to the ecology module. The environmental lecturers’ teaching approaches contributed to improving the students’ environmental attitudes and knowledge. When it came to the rapid transition to online teaching and learning, both the first-year School of Natural Resource Management students and environmental lecturers experienced benefits and challenges. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
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  • Date Issued: 2021-12

A data-driven decision-making model for the third-party logistics industry in Africa

  • Authors: Moyo, Faith
  • Date: 2021-12
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/53875 , vital:46022
  • Description: Third-party logistics (3PL) providers have continued to be key players in the supply chain network and have witnessed a growth in the usage of information technology. This growth has enhanced the volume of structured and unstructured data that is collected at a high velocity, and is of rich variety, sometimes described as “Big Data”. Leaders in the 3PL industry are constantly seeking to effectively and efficiently mature their abilities to exploit this data to gain business value through data-driven decision-making (DDDM). DDDM helps the leaders to reduce the reliance they place on observations and intuition to make crucial business decisions in a volatile business environment. The aim of this research was to develop a prescriptive model for DDDM in 3PLs. The model consists of iterative elements that prescribe guidelines to decision-makers in the 3PL industry on how to adopt DDDM. A literature review of existing theoretical frameworks and models for DDDM was conducted to determine the extent to which they contribute towards DDDM for 3PLs. The Design-Science Research Methodology (DSRM) was followed to address the aim of the research and applied to pragmatically and iteratively develop and evaluate the artefact (the model for DDDM) in the real-world context of a 3PL. The literature findings revealed that the challenges with DDDM in organisations include three main categories of challenges related to data quality, data management, vision and capabilities. Once the challenges with DDDM were established, a prescriptive model was designed and developed for DDDM in 3PLs. Qualitative data was collected from semi-structured interviews to gain an understanding of the problems and possible solutions in the real-world context of 3PLs. An As-Is Analysis in the real-world case 3PL company confirmed the challenges identified in literature, and that data is still used in the 3PL company for descriptive and diagnostic analytics to aid with the decision-making processes. This highlights that there is still room for maturity into using data for predictive and prescriptive analytics that will, in turn, improve the decision-making process. An improved second version of the model was demonstrated to the participants (the targeted users), who had the opportunity to evaluate the model. The findings revealed that the model provided clear guidelines on how to make data-driven decisions and that the feedback loop and the data culture aspects highlighted in the design were some of the important features of the model. Some improvements were suggested by participants. A field study of three data analytics tools was conducted to identify the advantages and disadvantages of each as well as to highlight the status of DDDM at the real-world case 3PL. The limitations of the second version of the model, together with the recommendations from the participants were used to inform the improved and revised third version of the model. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
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  • Date Issued: 2021-12

A spatial assessment of riparian vegetation density and implications for streambank erosion in relation to land tenure in the Mgwalana Catchment, Eastern Cape Province, South Africa

  • Authors: Maxama, Asakhile
  • Date: 2021-12
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/53864 , vital:46026
  • Description: Riparian vegetation provides an array of various ecosystem functions and has significantly shaped the conditions of catchments. It has strong controls on fluvial geomorphology and erosion processes. The Mgwalana catchment has been intensively studied over the years and the current environmental condition of the study has been linked to land use history. The catchment has been subjected to land use/cover changes (LUCC) over the years. However, spatial variations in riparian vegetation, their implications for stream bank stability and the contribution of land tenure systems to stream channel degradation are poorly understood. The study sought to assess the implications of the spatial variations in riparian vegetation density for stream bank erosion in relation to land tenure on a catchment scale. Land tenure units comprising the catchment of study are traditional and betterment villages (communal lands), and former white commercial farms. A three-pronged approach using GIS and remote sensing, field investigations and laboratory procedures for soil analysis was employed in this study. Variations of riparian vegetation density in the catchment were mapped using ArcGIS for the two land tenure units to assess the spatial variations of riparian density along stream reaches and to determine the spatial relationship between land tenure units and riparian vegetation diminution. Other mapped shape files include sediment accumulation zones to analyse the spatial relationship between riparian vegetation density and sediment sinks. LUCC classification and analysis of the Normalized Difference Vegetation Index (NDVI) were carried out in IDRISI Selva, using Landsat 8 TM imagery of 2018 to represent the current spatial riparian vegetation variations in the catchment. Field investigations were conducted to determine the coupling among hillslope gully erosion, riparian vegetation density and sink areas; and to assess physical characteristics of soil. This would permit an assessment of the implications of riparian vegetation for stream bank erosion and sediment accumulation within the tenure units. Soil samples were taken from scantily and densely vegetated stream reaches, as well as measurements of channel widths and depths. Analyses of soil physical properties viz; grain size distribution, bulk density, soil texture and aggregate stability were done. Results demonstrated that a sparse riparian vegetation distribution was consistent with the communal villages, confined to the upper catchment area. Dense riparian vegetation distribution was consistent with former commercial farms in the lower catchment area. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
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  • Date Issued: 2021-12

A value alignment smart city stakeholder model

  • Authors: Van der Hoogen, Anthea Vivian
  • Date: 2021-12
  • Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/54129 , vital:46309
  • Description: The concept of a Smart City has evolved over the last three decades and has attracted the increasing interest of the scientific research community. Unfortunately, many Smart City projects and initiatives do not provide the value expected by all the stakeholders. Many of the reasons for this relate to a lack of data management, data integration, data access and stakeholder participation. People are an integral part of any city’s ecosystem, and the Smart City concept was introduced to address the challenges of an ever-growing global population leading to the risk of depletion of economic, environmental and social resources. The problem addressed in this study is based on the challenges preventing the creation of the value of smart cities or stakeholders. Limited research has been published on the status of Smart City initiatives or on the impact of various success factors on the potential value creation for stakeholders including citizens. Studies on initiatives in developing countries, such as South Africa are even less. Whilst some challenges and constraints related to smart cities in Africa have been reported, there are no studies reporting on initiatives across the data value chain that consider all types of stakeholders, nor the impact of these initiatives. This study addressed this gap in research and designed a theoretical Value Alignment Smart City Stakeholder (VASCS) Model based on a Systematic Literature Review and a review of related theories. The model has important components that should form part of any Smart City project or Smart City initiative. These five main components are: 1) nine Smart City dimensions with related success factors; 2) four stakeholder roles (enablers, providers, utilisers and users); 3) the data value chain; and 4) the five phases of stakeholder benefits/value realisation that can be linked to; 5) stakeholder value alignment. This study applied the VASCS Model to Smart City initiatives in two case studies in the Eastern Cape Province of South Africa, which were the Nelson Mandela Bay and Buffalo City to investigate and understand the status of such initiatives and the alignment of value thereof. The stakeholder interviews were conducted in two rounds with various stakeholders of Smart City initiatives, referred to as cases in the two case studies. An expert review of the VASCS Model was conducted with eight experts in the field of Information Systems and Smart Cities. The findings of this review served to confirm the components of the model, with only minor improvements recommended. It was confirmed that all of the components need to be considered in planning Smart City projects. The first round consisted of six interviews with enablers and providers and the second round consisted of 22 interviews with users, utilisers and citizens. The interviews investigated the value and impact experienced by stakeholders of these initiatives, with a particular focus on the users, utilisers and citizens of the cases. The interview data was transcribed and qualitatively analysed by using Atlas.tiand Excel. The data was analysed according to the Technological, Organisational and Environmental theory constructs and other identified themes. The interview analysis findings revealed several drivers for these initiatives, which were primarily cost reduction, integration and quality assurance. The results also highlighted access to resources, such as technical skills as a challenge. Another challenge identified was connectivity related to access to data and the digital and physical divide that can impact decision making. The main benefits of Smart City initiatives highlighted were the provision of infrastructure, education and training and digitalisation. The theoretical contribution of this study is the VASCS Model, which can assist other researchers and practitioners with knowledge of the factors, drivers, challenges and value obtained in Smart City initiatives. The model has two supplementary components: A Stakeholder Classification Model and a Smart City Success Factor Evaluation Template. The practical contribution of this study is the potential use of the VASCS Model by practitioners, city management, researchers and other stakeholders, who can use the model, with the related model and template for planning and evaluating Smart City initiatives. The model can be used to classify the digital activities according to a Smart City’s success factors while evaluating the value created by these activities. The impact of these initiatives can then be assessed through value realisation and alignment for stakeholders. The scientific contribution is the adoption of the model to the cases in the Eastern Cape. To reveal in depth, rich, interview findings that provide important lessons learnt relating to the value created for the stakeholders and the addition of these findings to the body of knowledge. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
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  • Date Issued: 2021-12
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