ETD Collection
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Item Expecto patronum(2020) Edery, KyleOur natural world is currently undergoing a drastic and radical transformation! Human agency has led to the erosion of the very foundations of our livelihoods, economies, food security, health and quality of life. Ecosystems, which form our life support systems and our safety nets are shrinking and collapsing. At the heart of this collapse are pollinators, such as butterflies and bees, key species responsible for maintaining these vital ecosystems, whose very existence is being threatened by human activity. This thesis depicts a series of explorations, re-defining the environment and surface needed for pollinators in this new age of man vs nature, before manifesting and putting forth the creation of a version of an artificial envi-ronment. This version of an artificial environment is presented as a solution to sustain and revive endangered pollinators and the degrading context of the proposed site.This thesis looks at how architecture, in its physicality, can not only assist eco-systems and pollinators in their fight for survival but also act as a catalyst for a process of awakening and awareness. The intervention proposed in this thesis aims to create a space that negotiates between the two worlds of pollinators and humans, at the intersection of the built form and the natural environment. In doing so, this will ensure a space that benefits both people and pollinators, at their respective scales. The design of this new surface / artificial environment aims to aid pollinators year-round both naturally and through artificial means, while also showcasing their contribution to human life and research to aid their survival. The thesis demonstrates the demise of nature, illustrating the impact humanity, as a species, has had and continues to have on the natural world, primarily on the lives of pollinators. A focus on the demise of pollinators is addressed, as their brink of extinction stresses a fundamental link between the two causes of collapse and how by saving pollinators, nature in turn can be revived. By doing the above, this thesis will advocate for the creation of an artificial environment as an effective solution to sustain and revive South Africa’s endangered pollinatorsItem Taxon-free ecomorphological analysis of fossil bovids from the Sterkfontein and Swartkrans deposits, South Africa(2020) Sambo, RecogniseSterkfontein and Swartkrans caves (1 km apart) are situated in the Cradle of Humankind World Heritage Site, Gauteng, South Africa. The two sites hold records of the two Earlier Stone Age tool technologies (Oldowan and Acheulean), and have yielded significant fossil hominins in southern Africa that span the late Pliocene and early Pleistocene period. This is the first study in the Cradle which applies a ‘taxon-free’ ecomorphological approach to investigates palaeoenvironmental changes at Sterkfontein and Swartkrans caves between 2.8 and 1.5 Ma through the functional morphology of well-preserved bovid astragali. Seven measurements were taken on 55 bovid astragali following methods employed by previous studies. A Discriminant Function Analysis (DFA) was conducted to compare morphologies of unknown fossil bovids astragali from these two sites to published modern bovid astragali of known ecological adaptations (e.g., open cover, light cover, heavy cover, forest). Results show that morphologically, bovids from the two sites are adapted to a mosaic of habitats. Bovids from Sterkfontein Member 4 (STK-M4) ~2.8-2.4 Ma manoeuvered in less complex environmental settings such as open plains, grasslands, tall grasses, light bushes, as well as medium density heavy cover environments (e.g., bushlands, woodlands), and a riparian forest. Similar environmental conditions persisted to the time of Sterkfontein Member 5 East, Oldowan infill (STK-M5E) ~2.18 Ma although with more tree cover. In contrast, the environment at Swartkrans during the deposition of Member 1 Lower Bank, Oldowan (SKX-M1 LB) ~ 2.2 Ma was favourable to bovids adapted to light cover, moderate open cover and forest habitats with no heavy cover. The same conditions are evident during Swartkrans Member 2, Acheulean (SKX-M2) times ~1.5 Ma but it seems the environment was opening up more. These results suggest a time transgressive trend from medium density heavy cover and forest environments to more light cover and open environments associated with the expansion of grasslands between ca. 2.8 Ma to 1.5 Ma at the two sites. This fits well with the broader reconstructions of palaeoclimatic change in Africa and in the Cradle, which suggest drying trends resulting in more varied and open environments during the Plio-Pleistocene onwardsItem A Palaeolimnological determination of a regional industrial signal in the sediments of Mpumalanga Highveld Pans(2020) Spratt, Jesse PatrickFresh water endorheic wetlands are a scarce resource in South Africa and are threatened by human activities such as mining, abstraction, farming and other industry. The Mpumalanga Lake District (MLD) is a unique region comprising of over 300 endorheic pans differing in type. This provided the ideal regional setting for a pilot palaeolimnological study. The overall aim was to identify a regional industrial signal for anthropogenic influence by understanding the uniqueness of these pans through a palaeolimnological approach using historical lake sediments. A historical sediment record was established in order to identify any temporal changes in physiochemical characteristics over the last approximately 130 years. Four sites were selected so as to analyse a spatial aspect of contamination and to compare physical characteristics of pans in the MLD. Sediment samples were collected in the form of four lake sediment cores which were sub-sampled at 0.5 cm in order to understand down core trends. A bathymetric approach was adopted in which GPS, depth and water quality data were obtained in order to understand the physiochemical characteristics and morphology of these pans. Analyses performed included radio-isotopic dating through 210Pb, organic carbon content analysis through Loss on Ignition methods, sediment grain size analysis using laser diffraction and the analysis of the composition of major elements in these lake sediments using x-ray fluorescence (XRF) spectrometry. Bathymetry data was used to produce maps representing the physical morphological characteristics of these pans. Sediment data including major elements, organic carbon content and grain size data was analysed statistically and represented graphically in order to understand down core trends. Identified was the uniqueness of these pans and the MLD region as a whole. The pans differed in size, depth and in terms of the sediment properties of organic carbon, carbonate and sediment grain size distribution. Results showed a distinct difference between sites TPE compared to the other three sites in terms of bathymetry and limnology. It was determined that there are multiple fluctuations throughout the sediment record which represents a seasonal variation in climatic conditions. An attempt to observe trends of environmental and climatic change was made with varied success. An identification of a possible regional industrial signal was made with respect to major element compositional changes however the distinction between natural and anthropogenic sources was difficult to determineItem The use of geographic information systems (GIS) and remote sensing on the matchless amphibolite belt (MAB), gorob-hope area, Namibia(2018) Kaasheka, Elina KThe Matchless Amphibolite Belt (MAB) is a linear geological feature up to 3 kilometers wide and at least 350 kilometers long within the Damara Orogen of Namibia (Miller, 1983). The exact length of the belt is not well known due to the superficial cover of Kalahari sand, especially east of Windhoek, towards the border with Botswana. The Matchless amphibolite belt is associated with Neoproterozoic massive sulphide Cu-Au-(Zn-Ag) deposits (Breitkopf & Maiden, 1988; and Killick, 2000). Conventional geological and mineral exploration practices need enormous investments, a long time period plus intensive human labour especially in areas that are not easily accessible or with complex geological features such as the Gorob-Hope area. This study focused on the occurrence of mineralization in the Gorob-Hope area of the Matchless Amphibolite Belt and involved gathering, processing and interpretation of historic geological and remote sensing data using ENVI and ArcGIS software. These techniques were applied with a view to establish how the ore deposits are associated with the presence of the MAB and to establish the relationship between lithological units, the structures and the ore body localization. Application of ENVI and GIS techniques proved that it stands for an efficient and cost effective option of outlining mafic units, metasedimentary units, structures and ore body localization based on the available historical geological, and remote sensing data. The study also established that ore deposits found in the study area are controlled by structural features and are associated with MAB.Item The ecology of otters in an urban environment(2018) Ponsonby, Damian WinterUrban development has rapidly become the largest contributing factor of biodiversity decline across the planet. Regardless, certain species can survive these novel environments due to their opportunistic nature or occurrence in niche specific areas within urban areas. The aim of my study was to establish whether two otter species, the African clawless otter (Aonyx capensis) and the spotted-necked otter (Hydrictis maculicollis), in an urban environment showed similar ecological patterns in distribution (spatial arrangement), diet, and habitat use compared to conspecific individuals in areas with moderate to low levels of human disturbance. Firstly, I investigated the distribution and frequency of each species based on occurrence of signs (e.g. spraints and footprints) in relation to urban and peri-urban areas of central Gauteng, South Africa. Both species were present in central Gauteng, with a greater number of A. capensis signs found. No difference was observed between the number of signs found in urban and peri-urban areas for both species. Secondly, habitat variables measured near otter signs showed several differences in variables between urban and peri-urban areas. Otter movement through urban areas appeared to be associated with tall grass species, reed beds, and trees, which provided means of concealment for the animals, as well as avoidance of buildings to reduce human encounters. Thirdly, diet analysis based on prey remains in otter faecal samples resulted in lower than expected levels of crab and fish, and revealed higher than expected numbers of less common prey (e.g. birds and mammals) being consumed. Finally, the genetic diversity of individuals was measured using allele frequency to determine the level of reproductive success (ability to survive and produce viable offspring; Fisher, 1915) of A. capensis. Results showed a high level of genetic recombination between individuals in the population suggesting no movement restrictions are being experienced by otters, but genetic diversity was low. Otters are able to utilise resources available in this novel environment, which does not appear to be affecting movement, habitat utilisation or diet. A high genetic flow suggests successful use of urban areas, although there is concern about future genetic health in Gauteng based on the lower level of genetic variance.Item The ecology of sodic sites in the Eastern Transvaal Lowveld(1992) Chappell, CliveThe effect of sodium on clays dominates the formation and ecology of granitic eatenas in the Eastern Transvaal Lowveld. This study reviews the process involved and explains the soil, vegetation and erosion patterns in this landscape. Weathering parent rock gives rise to sodium in sufficient amounts to promote clay dispersion. Dispersed, mobile, clays respond to seasonal pulses of laterally moving soil water resulting in alternating zones of clay illuviation and clay deposition down hillslopes [Abbreviated Abstract. Open document to view full version]Item Prevalence and predictors of psychosocial outcomes amongst socioeconomically deprived primary school children in a rural setting in South Africa: the role of ecological factors(2015) Hlungwani, Tintswalo MercySouth Africa is passing through a phase of transition and children living in the country are still subject to many social and financial problems. They face high levels of social adversity, socio-economic deprivation, migration, displacement and morbidity. Rural South African children’s right to education and physical and mental health remains unfulfilled because of exposure to on-going adversity including poverty, family disruption through labour migration, malnutrition, inter-personal violence, chronic illness and death of family members due to HIV/AIDS. Although numerous studies highlight psychosocial problems amongst these children in South Africa and even document risk factors, there is paucity of studies that have focused on rural children’s mental health with consideration to both protective and risk factors. The study is focused on primary school children aged 8-12 in grades 5 and 6. It examines the prevalence of psychosocial problems among these children and determines the socio-demographic factors which can serve as predictors of psychological outcomes in these children. The study looks at both risk factors and protective factors as predictors of said psychological outcomes.Item Some impacts of sulfur and nitrogen deposition on the soils and surface waters of the Highveld grass, South Africa(2012-03-07) Bird, Theresa LeighAtmospheric deposition of sulfur (S) and nitrogen (N) as a result of fossil fuel combustion is known to impact ecosystem structure and function. Potential impact includes acidification of soil and surface water and mobilisation of metal ions, with the resultant loss of plant productivity, changes in plant species diversity and changes in biotic communities in aquatic ecosystems. Rates of S (~8 kg S ha-1 year-1) and N (>6 kg S ha-1 year-1) deposition to the grasslands of the South African Highveld are comparable to other industrialised areas where ecosystem impacts have been observed. As part of a larger project, this work investigated four aspects of ecosystem impact: changes in soil and river water chemistry as well as S and N mineralisation rates. Reassessment of the soil chemistry at 18 sites on the South African Highveld after a 16-year period showed increases in both acidic and basic ion concentrations for individual sites and when the values for these sites were averaged to represent the study region. Grouping the soils by clay content showed that all sites with less than 25% clay (16 of 18 sites) showed significantly reduced pH(H2O) values. Sites with less than 4% clay showed increased exchangeable acidity and decreased acid neutralising capacity. Spatial scaling and mapping from site to soil form and land type, showed that across 92% of the study area the pH(H2O) values had been reduced. This method identified the sandier soils, near the southern and eastern boundaries of the study area where rainfall is higher, as sensitive to additional acidic inputs via atmospheric deposition. Clay-rich soils occur in the drier central part of the study area, close to emission sources. It is suggested that this proximity to emission sources results in the co-deposition of basic and acidic ions, adding to the buffering capacity of the soils, resulting in small but significant increases in soil acidity status over the 16 years. Sulfur and N mineralisation rates, using the in situ incubation method at 11 sites, were found to range between -0.66 and 1.09 μg SO42- g-1 soil day-1 and -0.97 and 1.21 μg N g-1 soil day-1. This translated into an annual flux of between -40 and 9.9 kg S ha-1 and between 27 and 81 kg N ha-1 from the soil organic pools. The use of the in situ incubation technique to determine S mineralisation is a new Theresa Bird 9505067D development and is proposed for in-field studies where S and N cycling are of interest as the method allows for concurrent mineralisation rate determination. It was found that from a biogeochemical perspective the Highveld grasslands are under researched with respect to S and N and complete assessments of the S and N cycles are proposed. The S budget proposes accretion of S in the soil organic pool due to continued inputs via deposition and low losses to the atmosphere or deeper soil horizons. Nitrogen, however, appears to limit productivity in these grasslands because atmospheric inputs and mineralisation rates are approximately equal to plant uptake. In the assessment of river water quality it was hypothesised that between 1991 and 2008 concentrations of dissolved salts, sulfate, nitrate and ammonium would increase in surface waters at five sites draining the Highveld grasslands. The Department of Water Affairs water quality monitoring database was accessed to assess for spatial and temporal differences in water quality. Significant spatial differences were found; however, over time few significant increases were found to support the hypothesis: sulfate, nitrate-plus-nitrite, and ammonium were observed to increase at one site each. In addition, the export of nitrogen, as mass load, from natural grasslands was found to be negligible at <2 kg N ha-1year-1. A conceptual framework proposes that soil texture, distance from emissions and land use are key drivers in the response of the grassland soils and surface waters to atmospheric S and N deposition. Although the study identified the soils most sensitive to deposition, it is proposed that processes in the Highveld grasslands are not yet negatively affected by the additional sulfur and nitrogen inputs. Continued monitoring for impacts on ecosystem structure and function is advocated.Item Climate risk management options in the water sector(2012-03-05) Pema, KavitaExisting water management initiatives, strategies and policies in South Africa, ranging from the overarching water management legislative framework to the local-level practical operational aspects, were examined as a component of this project. The integration between National Strategies pertaining to water resource management and local implementation was addressed in terms of examining Water Conservation and Demand Management approaches and assessing the effectiveness of these approaches in addressing climate change risk factors in the water sector. Current South African regulatory instruments in the water sector allow adaptation and flexibility in order to address climate change impacts on the water resources in South Africa. The greatest obstacle in the implementation of effective Integrated Water Resource Management (IWRM) for climate change adaptation strategies is the lack of institutional support required from national levels of government to local municipalities. There is also a lack of strategic guidance and support in the form of policies specific to climate risk in the water sector in South Africa. Another important aspect of the IWRM, namely social learning, also suffers in the process due to lack of participation from key stakeholders and limited integration amongst interdependent sectors.