ETD Collection

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A proxy precipitation record for the Central Namib Desert using δ 13C analysis on Acacia erioloba
(2022) Mac Conachie, Kayla Storm
Namibia is one of the most arid countries in sub-Saharan Africa and aridity in the region is being exacerbated by climate change. Past climate reconstructions allow for deductions to be made regarding climate patterns and cycles; this facilitates more accurate future climate projections. There are few reliable meteorological or historical climate records for Namibia. While some long-term palaeoclimate records have been produced from proxies such as speleothems and hyrax middens, these offer relatively coarse temporal resolution. Dendroclimatological investigations can produce highresolution palaeoclimate reconstructions, with precise radiocarbon dating. Therefore, a very high level of calibration between tree rings and climatic data can be achieved. This research project uses the stable-carbon isotope approach and 14C dating on two Acacia (Vachellia) erioloba trees, (namely Husab-1 and 2) to test whether a proxy precipitation chronology for the Erongo region in central Namibia could be produced. Radiocarbon dates on the trees indicate that Husab-1 and 2 grew during the Little Ice Age (LIA) and the beginning of the modern era until the mid-20th Century CE. δ 13C analyses suggest that there was marked rainfall variability during this period, which is consistent with other palaeoenvironmental research for the Namib region, and other regions within the Summer Rainfall Zone (SRZ) of southern Africa. Although errors in the age model resulted in inaccuracies, a proxy precipitation record was produced. Comparisons between the Husab chronology and paleoenvironmental records, such as the Dante Cave speleothem records, and slack water deposits found along the Khan River, highlighted climatic variability within Namibia during the LIA. Furthermore, statistically significant relationships between Sea Surface Temperature (SST) anomalies, the Southern Annular Mode (SAM), and the proxy precipitation chronology indicate that these may have been key drivers for precipitation variability in the central Namib Desert during the past 600 years.
A spatial investigation into the colonial landscapes of sex in Johannesburg, Durban, and Cape Town, c. 1860 - 1910
(2022) O’Shea, Siobhan Reanne
In the late-19th and early-20th centuries British-colonial South Africa had several thriving sex industries. Sex work was an active feature in the illicit economies of Johannesburg, Durban, and Cape Town from their respective inceptions. Such 19th and 20th century sex work has been studied archaeologically since the 1980s in North America, but equivalent sustained work has not been conducted on contemporaneous South African sex work. With a focus on their respective spatial formations, the aim of this dissertation was to assess whether Johannesburg, Durban, and Cape Town’s sex industries were contained within distinct red-light districts between 1860 and 1910. In addition, I aimed to determine the visibility of sex workers and their own voices within the South African colonial archive. I generated spatial data that can be used for future archaeological investigation and identified potential material markers for identifying sex work-related sites. This was achieved for Johannesburg by producing a Google Earth map of brothel addresses acquired from the National Archives in Pretoria. Durban and Cape Town maps were produced using historiographical literature. Photographs of sex workers and pimps preserved in the colonial archive provided clues towards the potential materiality of sex work in South Africa, and the manner in which sex workers were criminalised in the colonial legal system
A zooarchaeological analysis of the faunal remains from Ratho Kroonkop, Limpopo Province, South Africa
(2024) Croll, Kathryn D.
Ratho Kroonkop is one of several hilltop sites in the Shashe-Limpopo Confluence Area (SLCA) that Schoeman (2009; also see Brunton et al. 2013) interpreted as a rain control site. Investigating how people (hunter-gatherers or farmers or both) selected, obtained, butchered and disposed of animal remains at Ratho Kroonkop, provides a window into people’s relationship with animals in this liminal space on the edge of the SLCA, and possibly, more broadly in society as a whole. In this study, I conducted taxonomic and taphonomic analyses on faunal remains from Ratho Kroonkop to elucidate engagement with animals between AD 900 and the 1600s. The identification of distinct temporally specific patterns in the Ratho Kroonkop faunal assemblage rests on a combination of my analyses of the faunal remains and radiocarbon dates. However, the interpretation of patterns in the data was informed by the comparison of the faunal assemblage with that from other sites in the region, and the integration of ethnography on both hunter-gatherers and farmers, and in particular, ethnographic accounts about rain control and beliefs related to animals. It can be challenging for archaeologists to tease apart mundane and ritual use of animals by people in the past, especially when limited ethnography is available. A possible avenue for engaging with these nuances is through exploring patterns within datasets, for example, the differences in faunal processing between the three areas of activity at Ratho Kroonkop; the two rock tanks have taxa that would not ordinarily be consumed and have more evidence for ‘ritual’ use of fauna than the Central Area. Consequently, I suggest that the mid-second millennium faunal assemblage from the Central Area relates to mundane faunal remains processing, whereas the faunal assemblage in the two rock tanks relates to less mundane purposes from the early to mid-second millennium. My study of the faunal remains from Ratho Kroonkop details the quotidian uses of animals at the site and delves into the human-animal relationships expressed at Ratho Kroonkop. Accepting Ratho Kroonkop as a rain-control site, the animals identified and their spatial locations at Ratho Kroonkop indicate that they transcended quotidian use. The animals were vital for rain control and particular animals (specifically Ovis/Capra v and very large mammals) had agency, potency and the power to prevent or withhold rain if treated inappropriately (in the case of hunter-gatherers).
An analysis of extreme temperature events in South Africa: 1960-2015
(2024) Van der Walt, Adriaan Johannes
Extreme Temperature Events (ETEs), which include heatwaves, warm spells, cold waves and cold spells, have disastrous impacts on human health and ecosystems. The frequency, intensity, and duration of ETEs is projected to increase due to climate change. Successful adaptation to ETEs requires an understanding of the contemporary frequency of these events, and their likely occurrence under climate change. However, very little research has been conducted on ETEs in South Africa, and only a few attempts have been made to identify and examine trends. This study addresses this gap in the literature through four key contributions. The first is a review of the published studies on ETEs and their effects in South Africa, providing key methodological and theoretical directions for future research. The second is the first statistical classification of seasonal boundaries in South Africa based on temperature data. This is imperative in facilitating the analysis of seasonal ETEs, and seasonal-resolution trend calculation. The third and fourth contributions involve the calculation of cold and warm ETEs respectively, using the ET-SCI for the first time in South Africa, and comparing the results to those for the ETCCDI. The review of the literature demonstrates the paucity of research in South Africa, and some of the key methodological challenges pertaining to the temporal and spatial resolution of data points; the indices used; and the interpretation of the results. The statistical classification of seasons demonstrates that the majority of the stations can be classified into four distinct seasons, while the statistically classified seasonal brackets include summer (October/November/December/January/February/March), early autumn (April) and late autumn (May), winter (June/July/August), and spring (September). The analyses of ETEs demonstrate that both hot and cold ETEs pose threats to South Africa and reveal a considerable spatial heterogeneity in the trends for each ETE index, providing input towards more effective adaptation planning for the regions under greatest risk.
An experimental study of invertebrate damage to bone and its application to archaeology
(2022) Mahomed, Tawfeeq
The field of forensic entomology stemmed from the presence of specific insects providing crucial information with regards to the context and timing of death. More specifically, insects are largely responsible for the removal of soft tissue, along with other tissues, such as hair, nails and bone. This feeding activity has two outcomes; they may be used to acquire valuable information regarding the circumstances around death, and they may produce alterations and modification of the body which may be misconstrued as an act of violence prior to death. Additionally, insect damage on bone may take the form of discolourations, holes, scratches and tunnels which may be mistaken as intentional anthropogenic modification, or pathologies. Within the archaeological field, damage by insects upon archaeological material, specifically bone, is seldom described, as forensic entomology studies generally focus on soft tissue evidence. Here the author shows that some families of beetle are able to inflict damage on bone, contributing to the fairly limited literature and highlighting the need for more research to be done. Raw and roasted chicken and lamb bones were exposed to three species of beetle and two species of fly. Results from experiment 1 indicated that Dermestes maculatus larvae and adults produced bore holes, destruction, gnawing and surface tunnel damage on the bone samples, whereas experiment 2 showed no macro or micro indicators of dermestid beetle damage. Results from experiment 1 indicated that Anomalipus elephas and Zophobas morio larvae produced destruction damage on the bone samples, whereas experiment 2 indicated that tenebrionid beetles and larvae additionally produced destruction, gnawing and surface tunnel damage. Results from experiment 1 and 2 showed that Omorgus (Afromorgus) melancholicus and Omorgus (Afromorgus) squalidus did not macroscopically or microscopically damage the bone samples. Results from experiment 1 and 2 showed that Calliphora vomitoria did not macroscopically or microscopically damage the bone samples. Similarly, experiment 1 and 2 showed that Megaselia scalaris did not macroscopically or microscopically damage the bone samples. Bone density is described as the ratio of a bones mass to volume, with less dense skeletal elements comprising more blood, grease and marrow, making them more susceptible to gnawing and destruction than elements of a greater density. Results have shown that the epiphysis shows a higher frequency of damage markers over the diaphysis for both chicken and lamb bones.
Assessing climate change compatible smallholder water management strategies in southern dry lands of Zimbabwe
(2024) Manyakaidze, Pascal
The rise in temperature, rainfall decline and increase in other extreme weather scenarios are some of the global climate change and variability challenges affecting most countries. The global south countries bear the most burden from changes in climate. Communities in dry lands continue to experience increasing pressure from water scarcity due to the increased frequency and magnitude of droughts. Smallholder farmers in dry lands keep counting losses of the accumulated productive assets, which recovery efforts cannot replace. The impact of climate change on Zimbabwe’s rainfed smallholder farmers' livelihoods and economies manifest in increased poverty and vulnerability at community levels. Against this background, the research aimed at assessing how smallholder communities in dry lands can adapt to climate change using climate-compatible water management strategies. The study employed interpretivism, and philosophical realism approaches to gathering empirical evidence in Save and Mazvihwa communal areas in Chiredzi and Zvishavane districts, respectively. Interpretivism and the realism approach enabled the gathering of indepth qualitative and provided quantitatively driven scientific and statistical data in response to the questions. The study participants were drawn from smallholder farming households, government departments, NGOs/CBOs officials, local authorities, extension officers, traditional leaders, village pump minders and water point committee members. A household questionnaire administered to randomly selected respondents gathered quantitative data, while measurements, direct field observations, focus group discussions, and key informant interviews provided qualitative data. Evidence from the study indicates the continued increase in climate change and variabilityrelated constraints affecting smallholder water management in drylands. Water harvesting opportunities are not fully exploited, climate and weather information communication is not effectively enforced, institutional arrangements are not utilised effectively, and ecosystemsbased water replenishment practice is not in force. The findings of this study highlight that water governance, climate and weather information services, behaviour change, private sector service provider roles, and risk management strategies need integration and implementation within the socio-economic context of the communities facing water stress. Key contributions to the body of knowledge, governance mechanism and a community of practice are made by the study through revealing gaps, areas of convergence and divergence in policy and practice, leveraging opportunities in climate change, and financial mechanisms. The study presented a “Systems-based Adaptive Water Management Framework” that provides sector-wide, multi-level linkages and proven approaches for achieving resilient water management that adapts to multiple scenarios, including ecosystems, financial, political and institutional arrangements. The study concludes that the susceptibility of dry land communities to water stress may be related to aggravating effects of climate change that need a sector-wide approach, accommodating context-based and institutional arrangements.
Assessing core reduction strategies in the Early Acheulean of East and South Africa
(2024) Moll, Rosa Matsileng
The earliest phase of the Acheulean technocomplex is represented in archaeological sites across East and South Africa. Typologically, there is some similarity between these regions, but little is known about how lithic technological strategies compare. If archaeological assemblages in East and South Africa compare, it could provide some detail into the regional technological evolution and how that is linked to hominid behaviour. Through a technological analysis of the core and Large Cutting Tool (LCT) assemblages from three South African sites (Sterkfontein M5W in the Cradle of Humankind, two layers from Pit 6 in Canteen Kopje, and two pits at Rietputs 15) and EF-HR, in Olduvai Gorge, Tanzania, comparable reduction strategies appear to have been practiced. At each site, the LCT and core flaking strategies are distinct processes, but in both cases the edge management sequences are similar (bifacial, alternating, and unifacial). Blank shape and edge angles are shown to be more relevant to reduction strategies than the size or raw material type of the blank. Throughout the earliest phase of the Acheulean technocomplex >1.5 Ma there appears to be a progressive change in core reduction strategies. In the earliest assemblages, cores are generally exploited along multiple surfaces with no structured organisation of flake scars. In slightly younger deposits at EF-HR, the Organised Core Technology layer and Canteen Kopje, and Pits 5 at Rietputs 15, ca 1.3 Ma, there is a shift to structured flaking of a core edge or surface, as well as continuous, intensive, organised and sometimes hierarchal reduction strategies. These reduction patterns are precursors to later technological developments such as the Victoria West prepared core industry. LCTs were primarily shaped using bifacial means, both traditional and alternating. The shape of the blank was more important for edge management, as acute angles required fewer flake scars to manipulate. These sequences reveal forethought about artefact production, which is comparable to continuous and structured core reduction sequences. Like cores, work needs to be done to understand if there are progressive changes in LCT production during the early Acheulean.
Assessment of water quality status of the Woestalleen wetland before and after rehabilitation
(2022) Mbulaheni, Lindelani
The key objective was to assess the water quality status of the Woestalleen wetland before and after rehabilitation using water quality data from five monitoring points, two upstream (KFBM1 and Dam), one within the wetland (KFBM2) and two downstream (KFBM3 and KFBM4) and to determine if the ecological status of Woestalleen wetland class has been upgraded from a Class D to a Class C or higher. The channelled valley bottom wetland conditions for the post rehabilitation activities of the Roodepoort Colliery were found to be badly altered (Category E). Changes to the wetland and the subsequent consequence on the condition of the wetlands is mainly linked to the widespread alien invasive vegetation, erosion, damming and current mining activities from the Colliery adjacent to the wetland area. Monitoring data during study period 1, before rehabilitation (July 2018 to July 2019), study period 2, during rehabilitation (August 2019-January 2020) and study period 3, after rehabilitation (February 2020-June 2020) indicated higher values of electrical conductivity, turbidity, suspended solids, total alkalinity, chloride, sulphate, ortho phosphate, and sodium at the upstream site KFBM1 which were not compliant to the provided water quality limits on the WUL. Therefore, there are water contamination issues that emanated from upstream of the mining area. Higher values of TSS, EC, turbidity, and sulphate during study period 1 at downstream sites than upstream sites were also observed, this implies that the mine may have contributed to the water contamination of Woestalleen Spruit. Most of the water quality variables such as electrical conductivity, turbidity, suspended solids, total alkalinity, sulphate, ortho phosphate, and sodium were found to be noncompliant to the WUL both at upstream sites and downstream sites during study periods 1, 2 and 3. Significantly higher concentrations of variables such as hydrogen ions, sodium, chloride and sulphates were observed at downstream sites, KFBM2, KFBM3 and KFBM4 as compared to upstream sites, KFBM1 and Dam before, during and after rehabilitation. Therefore, mining activities may have contributed to acid mine drainage leading to these changes, even though the upstream water quality arriving at the mining area was already non-compliant and lastly the Woestalleen wetland rehabilitation has not yet improved water quality downstream. The PES of Woestalleen wetland further degraded from class D to E.
Coastal foraging of Turbo sarmaticus at Klasies River Main Site: an experimental approach
(2024) Holmes, Carl Louis
An increase in shellfish exploitation and strong seasonal fluctuations in terrestrial foraging at ca. 100 000 years ago along the Cape coast has been noted. It is hypothesised that marine foraging provided a more reliable year-round source of nutrients. As Turbo sarmaticus (alikreukel) is one of the major prey species found at Middle Stone Age (MSA) sites along the southern Cape, and Klasies River Main Site (KRM) specifically, this species was targeted in an archaeological and actualistic study. T. sarmaticus specimens were collected and processed by two participants to examine the possible methods used by MSA foragers and the meat was extracted using three tool types (bone, lithics, wood). Some specimens were cooked whilst others were processed raw. An analysis of the lengths of T. sarmaticus opercula of the ca. 100 000 years ago Shell Midden One (SMONE) layer from KRM shows that the archaeological opercula are similar in size to the experimental sample. A larger proportion of the archaeological opercula, however, fall within the smaller size range. An age index was developed for T. sarmaticus by correlating operculum size to shell size. This suggested that the archaeological specimens were younger when collected, or that they foraged during spring or winter. The opercula from SMONE are markedly smaller than other MSA II opercula from the Cape coast but bigger than LSA opercula. This might be related to more intensive predation, seasonality and sea surface temperature. A taphonomic analysis of both the experimental and archaeological samples was undertaken. The experimental specimens that were processed raw indicated percussion marks typically placed in the 3rd and 4th wedges. A proportion of the archaeological sample shows this pattern as well. This shows that some of the archaeological samples may have been raw extracted. Furthermore, the breakage types are very similar in both samples, however post-depositional breakage only affected the archaeological sample. This study demonstrates that broader insight can be developed through an actualistic study combined with a taphonomic analysis.
Evaluation of climate model simulations of boundary layers in the Southern hemisphere
(2022) Lekoloane, Lesetja Ephraim
There is a constant need to improve the simulations of weather and climate across different timescales. In this study we evaluate the simulations of Southern Hemispheric boundary layers by a variable-resolution global atmospheric model named the conformal-cubic atmospheric model (CCAM). To do the evaluation, we firstly determine a climatology of present-day ABL attributes from atmospheric soundings at three weather stations located in the high-latitudes (Syowa), mid-latitudes (Marion Island), and subtropical continent (Irene). We then proceed to evaluate how the CCAM simulates attributes of the ABL climatology over the three locations. Observational radiosonde data indicates that there persistently exists a temperature inversion over Irene at 00h00 UTC, throughout all the months of the year. It was found that this inversion is more intense during the autumn and winter seasons, while it is not as pronounced during the spring and summer seasons. Stability analysis over Marion Island indicated that the nearsurface atmosphere is neutrally stratified during all the seasons at 12h00 UTC. The radiosonde data over Syowa also indicated the presence of surface-based inversion at 00h00 UTC for all the months of the year. The surface-based inversion was also observed for 12h00 during all the months except the summer months, May, October and November. It was also found that monthly variability within the different seasons are prominently observed during the transitional seasons of autumn and spring, especially for thermodynamic variables. An interesting feature which was also observed over Irene and Syowa throughout all the seasons is a bulge in relative humidity above the surface. For Irene this is true for all the months of the year at 12h00 UTC, while for Syowa this bulge is observed for both 00h00 UTC and 12h00 UTC for all the months of the year. It is currently not known why this bulge exists, but a hypothesise is that it is due to the presence of low-level jet (LLJ). In terms of the model evaluations, it was also found that there is persistent positive bias of moisture variables – dewpoint temperature and relative humidity. This is especially true for the spring and summer months over Irene, while autumn and winter months indicate pronounced negative bias near the surface. Over Marion Island the positive bias of relative humidity is even more pronounced and persists throughout the four seasons at both 00h00 UTC and 12h00 UTC hours. This may be an indicator that the CCAM model is too moist above the surface over the two stations. Irene ABLH values based on calculations from observations were found to be lower than values simulated by the CCAM at 12h00 UTC throughout the four seasons, with an overestimation of more than 900 m during spring. On the contrary, the CCAM underestimated 4 ABLH values at 00h00 UTC for all the four seasons over Irene, with differences being only as much as 210 m for the winter season. Over Marion Island, CCAM consistently underestimated values of the ABLH for both 00h00 UTC and 12h00 UTC. An exception occurred at 00h00 UTC during the winter season, which indicates an overestimation of the ABLH by 550 m. Over Syowa, the differences between modelled and observed ABLH were not as pronounced as in both Irene and Marion Island. The smaller differences can be attributed to the presence of the surface-based inversion CCAM depicts fairly well.
Events-based small-town tourism: exploring the South African tourism sector under environmental and climate challenges
(2022) Mahlangu, Mazozo Nomthandazo
Tourism is one of the fastest emerging industries in the world which has contributed substantially to South Africa's Gross Domestic Product (GDP) throughout the years. Tourism is an integral part of the South African economy and culture, at the national and local scale. This study examines small-town tourism and the effect that events-based, wedding, natureand phenology-based tourism has on the success of the tourism sector of Chrissiesmeer, a small town located in Mpumalanga, South Africa. This study aims to explore climate- and phenology-related threats to tourism in Chrissiesmeer, through the town’s tourism sector and its reliance on climate and phenology, gauging the perceptions tourists and tourism operators hold regarding climate-related threats to tourism, and lastly, assessing the predictability and sustainability of tourist activities and annual events at Chrissiesmeer. This study takes on a mixed-methods approach that employs the use of both qualitative and quantitative data and the triangulation of results was a tool used to integrate and analyse each form of data collected to reveal common themes and patterns. Key-informant semi-structured interviews, comprehensive tourist questionnaires, and online reviews analysis were tools used to engage with the experiences of tourism in Chrissiesmeer and climate-related perceptions of former tourists and tourism operators. Image analysis of Instagram posts was conducted to compile a comparative contemporary phenological record that was compared to phenological records to provide estimated predictions of future phenological patterns of the plant and animal species identified in the study. The results demonstrate a clear link between events-based, small-town and nature-/phenology-based tourism. Nonetheless, many aspects of the tourism sector at large have some degree of dependency on the natural environment, climate, and plant or animal taxa. Thus, it is of great importance that the Chrissiesmeer tourism sector considers the potential and present effects of environmental and climate change because the majority of the most lucrative festivals, events and tourism activities are dependent on the phenological phases of certain plant and animal species. With shifting phenology being the most sensitive and earliest response to increasing global temperatures, tourism operators and small businesses in Chrissiesmeer must prepare adequately and adapt to these imminent effects, to maximize predictability and the sustainability of the key elements of the town’s tourism sector.
Exploring extreme rainfall events in KwaZulu-Natal over the period 1989-2019
(2024) Ntleko, Thabisile Phiwengomusa Zibusisozonke
Changes in weather and climate extremes have been observed across the globe. These include an increase in the frequency, magnitude, and severity of extreme events, have been attributed mainly to climate change due to increased anthropogenic activity since pre-industrial times. Although these weather and extreme events have increased and intensified globally on average, some spatial and temporal variations of trends are evident at regional scales. This study was conducted to explore the incidence and trends of extreme rainfall events over KwaZulu-Natal for the period 1989-2019. Rainfall data was sourced from the South African Weather Service for 11 stations distributed across the province. Extreme climate events (ECEs) were identified by calculating subsets of the World Meteorological Organisation (WMO) Expert Team on Climate Change Detection Indices (ETCCDI) and WMO Expert on Sector-Specific Climate Indices (ET-SCI) for each of the 30 years of interest. Thereafter, trends in these extreme climate events were calculated using linear regression. The results reveal marked spatial and temporal differences in both the occurrence of the ECEs and their trends. The incidence of ECEs depict a seasonal pattern, where majority of events occur during the summer rainfall months. However, over the coastal regions ECE’s occur throughout the year and exhibit more frequent and intense events compared to overland regions. The trend analysis detected a majority of decreasing trends in the frequency, intensity and duration of extreme rainfall events for the period of study, with only 10 of the 77 calculated trends being statistically significant. The spatial distribution of trends was heterogeneous for most parts of the province apart for the KwaZulu-Natal Midlands, which consistently observed decreasing trends for all calculated indices.
Historical development of the KwaZulu-Natal Museum’s archaeological archive: the case of the Michael Moon collection
(2022) Munzhedzi, Mudzunga F.
Museums are defined as institutions where treasures of humankind are stored. These treasures include memories of people of the world, their cultures, dreams and hopes, most commonly as represented by material culture. This dissertation considers one aspect of the archaeological archive at the KwaZulu-Natal Museum, the contribution made by amateur archaeologist Michael (Mike) A. Moon. Most of his collection comes from sites exposed by and then lost to development beyond the view of professional archaeologists. The collection covers much of the vast range of human endeavour in south-eastern Africa and constitutes a valuable addition to our knowledge base of the past in KwaZulu-Natal. The archaeological usefulness of the collection relates to its ‘co-production’ through Moon’s dialogue with professional archaeologists over many years. I examine the Mike Moon collection by looking into detail of the individual artefacts so that I would be able to learn more about their archaeological value as I analysed them. My analysis of the Moon collection is supplemented by the interviews I conducted with Mike Moon before he died in January 2021. Additional interviews were conducted with two professional archaeologists who had an opportunity to work with Mike Moon on occasional basis, Aron Mazel and Tim Maggs, an officer from the provincial heritage resources authority, Amafa, Celeste Rossouw, and a close friend, Jennifer Gregory. My study engages the discussion with a focus on the key findings of my analysis of the Mike Moon collection housed at the Museum as well as the interviews with him and four respondents. It also touches on Moon’s private collection housed at his house, which he acquired through various methods over the years. I conclude with the discussion on how others perceive amateur archaeology as well as how amateur archaeologists feel following mixed treatment experiences by professionals.
Mapping and monitoring the impacts of climate variabilities on rangelands in North Darfur, Sudan
(2022) Jakata, Chido
In North Darfur, rangelands are of great importance as they support economic activities such as pastoralism and help in environmental management by reducing desertification. However, alterations or shifts in rangelands may take place due to climate variabilities posing problems for resource and land managers as they seek to familiarise to variations in the environment and monitor and partially control effects of climate variability. Shifts in rangeland quality and quantity which may be experienced owing to climate variabilities pose problems for environmental managers as they are working on conserving and mitigate adverse impacts of climate variabilities on rangelands. The region has experienced various environmental and social impacts because of its ecological structure and geographical location. Massive alteration of the rangelands on farmlands have been experienced, leading to conflicts between farmers. Therefore, the monitoring of the rangelands for a longer season in North Darfur could lead to the increase in rangeland productivity. Conventionally, field-based surveys including focus groups, in-depth interviews, ethnography, questionnaires, and intercepts were implemented to monitor land use changes on bare land, rangelands, waterbodies, and farmlands. However, these methods have low spatial coverage making them unreliable in studying land uses and land cover change, especially over long periods of time. In this study, remote sensing (RS) Landsat 4,5,7 and 8 images and temperature and rainfall products were used for the period between 1985 and 2020 at five-year intervals. For each image, 29 scenes were downloaded to cover the whole study area. Using the climate data, rainfall and temperature anomalies were calculated to quantify climatic trends. Random forest classification was run in Aeronautical Reconnaissance Coverage Geographic Information System (ArcGIS). The land cover classes used in this study were bare land, farmlands, rangelands, and water bodies. Additionally, the Soil Adjusted Vegetation Index (SAVI) was used monitoring rangeland productivity in North Darfur. The findings of the study outlined and proved the early part of the period studied rangelands were dominant, covering up to 20% of the study area. Rangelands also covered most of the southern parts of the study area. However, by 2020, rangelands only covered 8% of the total area. Waterbodies concurrently decreased significantly, covering just 1% in 2020, where previously they had covered 18%. In contrast, farmlands became more dominant in the southern part of North Darfur by 2020, covering 33% of the total area while bare grounds increased to 58%. It is recommended that the government and the environmental managers in Sudan implement measures that help in safeguarding rangelands for sustainability.
Mapping transit-oriented economic and social impacts of Gauteng’s postApartheid spatiality: an analysis of precarious workers associated with the Casual Worker’s Advice Office
(2022) Dor, Graeme
Precarious forms of employment have become a prominent feature of the labour process, with varying factors contributing to workers’ level of precariousness, informed by inherent social, economic, and spatial dynamics. The influence of social and economic dynamics is well researched and understood, yet the influence of spatial dynamics is largely unexplored. The aim of this research wasto explore the spatial attributes and factors that define precariousness, in the context of the post-Apartheid Gauteng region, through a case-based study of the Casual Workers Advice Office (CWAO). Founded in 2011, and based in Germiston, Gauteng, South Africa, the CWAO represents precarious workers, predominantly labour broker workers, providing labour rights-related advice and support to workers spread across the Gauteng City-Region (GCR). Formed out of the recognition that a growing section of the working class is being subjected to new and precarious forms of employment, the CWAO provided an ideal case scenario to assess the influence of Gauteng’s unique post-Apartheid spatiality on precarious workers. To assess this, advanced geostatistical and GIS-based analytical techniques were employed using an exploratory spatial data analysis (ESDA) approach. This necessitated analysis of three datasets composing data from the CWAO, in worker membership details and an accompanying survey, and from the Gauteng City-Region Observatory’s (GCRO) Quality of Life (QoL) 2017/2018 survey. These datasets enabled the identification of spatial patterns, the creation of a spatial regression model and a job accessibility index, which demonstrated the presence and complexity of spatial dynamics associated with the distribution of precarious workers across the GCR. First, the location of CWAO associated workers’ residence and associated workplace was mapped, with findings showing no significant difference in the distance that these workers reside from work compared to respondents from the GCRO QoL survey A geographically weighted regression (GWR) model was then applied given its ability to generate individual regression coefficients as a continuous function across space, providing a valuable measure of spatial heterogeneity. A percentage change increase in model performance of 20% was achieved when compared to a nonspatial regression model, highlighting the effect of spatial heterogeneity across the study area and the importance of adopting spatially weighted variables in predicting employment status, the selected measure of precariousness. In addition, the creation of a job accessibility index, derived from location data in residence and workplace coordinates of precarious workers associated with the CWAO, alongside a net wage after commute (NWAC) layer developed from the GCRO QoL survey highlighted spatially dynamic job accessibility scores across the GCR. Increased job accessibility for areas located centrally within the GCR, corresponding to the economic hub, was contrasted by a less distinct spatial pattern in a NWAC layer, a component of the accessibility index. Nevertheless, the product of the accessibility index displayed a statistically significant association, at a 5% level of significance, with employment status. Overall, the results outlined the complexity of Gauteng’s unique spatiality and the necessity for developing multi-dimensional analyses to better understand the underlying spatial dynamics associated with precarious workers. Defining the spatial conditions that influence workers’ level of precariousness provides the opportunity to implement practical solutions in advice, advocacy work, and organizing strategies to ensure workers’ needs are addressed. The analyses performed in this study have laid the foundation for facilitating future research on the spatial dynamics of precarious workers.
Modelling the spatial distribution of Lantana Camara in the inkomati catchment in Mpumalanga, South Africa
(2024) Mtyobila, Vuyelwa Emmaculate
Lantana Camara is a highly problematic invasive species, extensively studied for its spatial distribution. The present study was conducted to investigate Lantana Camara's spatial patterns across the topographic variations within the Inkomati catchment, located in Mpumalanga, South Africa, using the Random Forest and Maxent algorithms with Sentinel-2 data within Google Earth. Lantana Camara covered 34.86% of the study area, with a user's accuracy of 91% and producer's accuracy of 84%. Elevation strongly influenced the species' spatial distribution, while the Topographic Wetness Index had minimal impact. MaxEnt vulnerability maps revealed higher vulnerability to Lantana Camara in the central western part of the study area than the eastern part. The model using topographic variables achieved the highest accuracy (AUC = 0.88), surpassing the predictive model with Sentinel-2 bands (AUC = 0.81). The study suggests that the Sentinel-2 Red Edge and NIR bands, combined with Random Forest, offer accurate insights into Lantana Camara distribution, aiding in identifying regions vulnerable to its invasion.
Monitoring and modelling settlement growth using object-based classification techniques: a case study of Pretoria north, South Africa
(2022) Oliphant, Thando
Accurate and up-to-date maps of settlement distribution are critical for urban planning, monitoring, and management decisions. Remote sensing is useful for monitoring the dynamics of urban growth over large areas. Over the year’s urban built-up areas have rapidly increased in Pretoria North. Built-up layers for 1990 and 2017 were used to model settlement growth for 2025 using cellular automata (CA) incorporated with the artificial neural network (ANN) model within modules for land use change simulations (MOLUSCE) QGIS plugin. A rule-based classification object-based image analysis (OBIA) approach was used for extracting built-up and settlement types from highresolution SPOT multispectral imagery. A total of seven SPOT images for the period 1990 to 2017 with a five-year interval were used to assess and quantify built-up area growth. The results from the study indicated urban increases from 65.2 km2 in 1990 to 144.4 km2 in 2017. Post-classification change detection technique was used to quantify built-up area growth. The results from the study also showed a significant urban expansion of 44.34 km2 , which represents a 47.3% growth that occurred during the period between 1994 and 2000. The overall accuracies from images for years 1990 – 2017 ranged from 80% to 87%. Settlement growth was measured by examining changes in built-up areas over the years. The study showed an increase in formal and a decrease in informal areas during the period 2005 to 2017 as a result of housing upgrades. The projected results for 2025 revealed that built-up areas will increase in the coming years. It was found from the results that SPOT satellite imagery and OBIA are valuable for modelling urban growth. Information derived from the study can be used by decision makers for planning and management purposes.
Perspectives on climate change and energy security in South Africa: a study of Eskom
(2024) Rasimphi, Khuliso James
Global changes in climatic conditions have both direct and indirect implications on various energy sources and systems, particularly in terms of energy generation vis-à-vis security for sustainable social-economic development. This study examined the relationship between climate change and energy security in South Africa, focusing on energy production, accessibility, and affordability as key determinants. The investigation also explored measures to minimise Eskom’s carbon footprint and opportunities for transitioning the energy sector to cleaner energy sources. A mixed research method, including structured questionnaire surveys, semi-structured interviews, observations, and existing records, was used for data collection. The data was mainly analysed by use of the Microsoft Excel package to generate statistical correlations and relationships to draw the key conclusions contained in this paper. Eskom coal power plants’ ten-year (2010 to 2020) carbon footprint was found to be constantly above 200 million per year. The power utility’s ten-year CO2e trend was primarily influenced by production activities. This is because all Eskom’s coal power plants (except for Medupi) do not have CO2e abatement technology, and the available technologies in the market are too expensive. The study also found that Waterberg (LP) and Nkangala (MP) regions, where most coal power plants are located, have been receiving inconsistent and insufficient rainfall from 2010 to 2021; and projections are suggesting a further decline in precipitation distribution and incline in average temperatures in these regions. Despite all these glaring climate change implications, the current study found that water consumption (2020 to 2021 trend) at coal power plants remained high even in periods wherein energy availability factor had dropped, and therefore indicative of thermal inefficiency. The study also found that South Africa’s slow approach in building a climate change resilient and adaptive energy system was caused by a slow and ineffective implementation of IRP. Thus, South Africa must embark on a decisive transition programme to cleaner energy sources mix as a critical and urgent measure to decarbonize and enhance the energy sector’s resilience against climate change effects, and ensure energy availability, reliability and affordability. The study concludes that Eskom coal power plants should focus their efforts on resolving maintenance problems, operational inefficiencies, and developing adaptation strategies to decarbonize and build resilience against climate change vulnerabilities such as irregular precipitation and high temperature, while ensuring energy security. The energy policy and IRP should be adaptive and continuously informed by regional research to determine the most suitable energy sources for specific regions to ensure an effective transition to cleaner energy systems.
Phenological advance in the South African Namaqualand Daisy Bloom over the past decades
(2024) Snyman, Pascal Ludwig
Climate change is driving changes in environmental suitability, competitive dynamics and phenological cycles of plants and animals. Through the analysis of the timing of phenological events the impact of climate change on plant and animal species can be measured and assessed effectively. In this study the impact of climate change on the timing of bloom of Namaqualand daisies is explored. Although the Namaqualand is described as a desolate and arid region during the summer months, the region is transformed into a wonderland of colours during the springtime flowering. Using documentary sources including newspaper archives from The Rand daily Mail, Volksblad and Die Burger as well as social media records from Flickr and iNaturalist, a phenological dataset spanning 1935-2018, including first flowering, full bloom and end of bloom dates for the Namaqualand daisies was compiled. First flowering and full bloom phenology of the Namaqualand daisies are advancing significantly at rates of 2.6d.decade-1 and 2.1d.decade-1. Climatic data, collectively spanning 1959-2018, from seven Namaqualand weather stations were individually correlated to the three flowering datasets. Calculations reveal that temperatures are increasing significantly in Namaqualand. The overall increase in temperature, from 1959-2018, for all seven assessed weather stations in Namaqualand is calculated at 1.18°C. Although no significant changes in precipitation were calculated, five out of the seven weather stations demonstrate slight decreases in precipitation over time ranging between 0.05-9.32mm from 1959-2018. The timing and amount of precipitation in the Namaqualand region is highly variable over time. For the periods spanned by both climate and phenology data, the relationships between the two were explored. Increasing temperatures are driving the calculated advances of the daisy flowering dates at statistically significant rates of change ranging from 0.01-0.11d.°C-1. The main climate drivers of Namaqualand daisy flowering phenology are winter and spring temperatures, the onset of the winter rainy season during April and May, and total winter precipitation. The rates of advance and climate drivers are broadly consistent with global phenological meta-analyses and records for the Southern Hemisphere. The advances in the timing of Namaqualand daisy flowering will have a significant impact on the tourism sector in the region, as flower viewing tours need to be prearranged months in advance.
Projected changes in the seasonality of rainfall and temperature over Southern Africa under low mitigation
(2022) Mfopa, Caroline Reitumetse
The single most prominent characteristic feature of southern African climate is its pronounced dry-wet seasonality, as opposed to the warm-cold seasonality that dominates climate of the high latitudes of the Northern Hemisphere. It is thought that the African savannahs, the dominant biome in southern and East Africa, evolved in the presence of fire and dry-wet seasonality over the last 10 million years. Global warming is already impacting on southern African climate, with the interior regions recording a rate of temperature increase almost twice the rate of global warming, over the last several decades. The main aim of this research was to investigate how regional climate change in southern Africa may impact on the seasonality of rainfall and temperature across the region, using the large ensemble of CMIP6 global climate model projections. Verification of the climate models revealed that they are capable to simulate intraannual variability (that is, the seasonal cycle) of both rainfall and temperature in southern Africa with remarkable realism. This holds true for regions with diversely different climatic regimes: the winter-rainfall region of South Africa, the larger summer rainfall region of southern Africa, and the bimodal rainfall region of East Africa. There is a single exception, namely the narrow all-year rainfall region of the Cape south coast of South Africa, where the correlation between the model simulations and observations in terms of intra-annual rainfall variability is substantially weaker than for other regions in southern Africa. The CMIP6 ensemble projects general reductions in rainfall over southern Africa under low mitigation, with corresponding drastic increases in temperature. These results confirm the 2018 classification by the IPCC SR1.5 report, of the southern African region being a climate change hotspot: when a warm and dry region becomes even warmer and likely also drier, the options for adaptation are limited. There are some important exceptions, in terms of the general pattern of change projected by the CMIP6 ensemble. The first is the northernmost parts of southern Africa, located in the tropical savannah zone, where increases in rainfall are projected. This pattern of change relates to the expansion of the humid tropical belt in a warmer climate. The second is the eastern escarpment areas of South Africa where increases in rainfall are similarly projected, driven by an increase in specifically summer rainfall. This implies iv an increase in the nature of rainfall – namely more intense rainfall events in summer and an increase in the amplitude of dry-wet seasonality. For most of the southern African region, however, general drying is projected, in conjunction with drastic warming. In fact, the CMIP6 ensemble projects staggeringly large temperature increases over the interior regions of southern Africa under low mitigation relative to 1979-2014. Over large regions of the interior, and across all seasons, this change is in the order of 5 °C by the end of the century. Such drastic increases in temperature, which translates to enhanced evaporation from soils, in combination with projected reductions in rainfall effectively suggests a longer burning season, and a shorter growing season (through reductions in soil moisture). The results point to the need for the region to focus strongly on climate change adaptation actions, in addition to its efforts on fairly contribute to greenhouse gas mitigation.

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