School of Geography, Archaeology and Environmental Studies (ETDs)

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Remote sensing survey of archaeological sites in the Shashi- Limpopo Region
(2020) Thabeng, Olaotse Lokwalo
The African continent is rich with archaeological heritage, which needs to be preserved for the current and future generations. The majority of archaeological heritage sites in Africa are facing disappearance due to a number of challenges including looting, destruction from developments, expansion of agricultural land and natural hazards. Documentation and monitoring of archaeological heritage sites, therefore, is of paramount importance for effective site management and preservation. However, archaeological heritage sites in the continent are poorly documented and monitored due to a number of factors including lack of funds by heritage management institutions, lack of trained personnel and inaccessibility of some areas due to conflicts or land ownership rights. Traditionally, the documentation and monitoring of archaeological heritage sites in Africa have been done through fieldwork, which is costly, time-consuming and difficult to carry out over large areas. Remote sensing offers a relatively fast, cheap, systematic and reproducible method of surveying and monitoring archaeological sites over large and/or restricted areas. Remote sensing techniques are used to identify earth surface features based on their spectral signature, which is the variation of reflection or emittance of materials’ electromagnetic energy. Spectral signatures for identifying archaeological sites are not universal, and an assessment of the applicability of remote sensing techniques in different archaeological landscapes is needed. The aim of this study, therefore, was to investigate the potential of using remote sensing techniques to document archaeological sites previously occupied by farming communities, which are traditionally associated with the Iron Age period in Southern Africa, using the Shashi-Limpopo case study. The first part of this study gives a review of the use of remote sensing in the African archaeological context. Despite it being a fast, cost-effective and systematic method of survey, the results of this study have demonstrated that remote sensing is not widely used in archaeological applications in Africa. The aforementioned situation calls for studies investigating the potential of using remote sensing techniques to fast track archaeological site survey, documentation and monitoring in the continent. The chemical composition of materials characterising different features have more or less subtle variations that, in turn influence the spectral behaviour of soil. This is an important principle that can be used for distinguishing archaeological soils from non-archaeological soils and can potentially help in discriminating different archaeological signatures. As such, the second part of this study investigated the possibility of using field spectrometer measurements to discriminate middens, non-vitrified dung, vitrified dung and non-sites (natural soils) characterising archaeological landscapes previously occupied by farming communities. It then investigated the presence of differences in the chemical composition of elements between middens, non-sites, vitrified dung and non-vitrified dung. The findings indicated that there is a statistically significant difference in the concentration of soil elements between non-sites, middens, vitrified dung and non-vitrified dung byres. They also indicated that some bands in the visible and shortwave infrared regions of the electromagnetic spectrum important bands for predicting the aforementioned archaeological sites and non-archaeological sites. In the third part of this study, the ability of multispectral sensors to discriminate archaeological and non-archaeological features in Shashi-Limpopo confluence area was investigated using field spectral data resampled to the spectral resolutions of common multispectral satellites namely GeoEye, Landsat 8 OLI, RapidEye, Sentinel-2, SPOT 5 and WorldView-2. This is because the spectral and spatial resolutions of various multispectral sensors determine the size and the type of archaeological data a sensor can detect. As such, another goal of this study was to identify multispectral sensors with the optimum spectral resolutions for detecting middens, non-vitrified dung, vitrified dung and non-sites. Additionally, the performance of advanced classification algorithms (random forest and support vector machines) in discriminating middens, non-vitrified dung, vitrified dung and non-sites was also investigated. The results proved the possibility of using multispectral satellites in mapping middens, non-sites, vitrified dung and non-vitrified dung sites. These results initiated the need to upscale the test to actual satellite images. The fourth part of this study assessed the possibility of prospecting for archaeological sites previously occupied by farming communities in the Shashi-Limpopo Confluence Area, using a very high-resolution satellite WorldView-2 image. The findings have shown that WorldView-2 satellite images and advanced classification algorithms can be used in prospecting for archaeological sites previously occupied by farming communities in Shashi-Limpopo Confluence Area. Finally, the ability of geographic object-based image analysis (GEOBIA) based on random forest and support vector machines, to discriminate archaeological and non-archaeological features on a very high-resolution satellite WorldView-2 image was investigated. The results of this study demonstrated the robust ability of the GEOBIA to integrate spatial attributes into the classification model improves the chances of separating materials with limited spectral contrast. Generally, this study has shown that remote sensing techniques can be used to map archaeological landscapes characterised by middens, non-vitrified dung, vitrified dung and non-sites. This will help archaeological heritage managers and researchers to document and monitor sites in archaeological landscapes characterised by the aforementioned features in a fast, systematic, reproducible and cost-effective manner
Climate change and heritage tourism: threats to Makgabeng in a regional context, Limpopo South Africa
(2020-11) Mcpherson, Fazlin Ahdielah
The Makgabeng area is situated in the north-west corner of the Limpopo province in South Africa. The Makgabeng area is an emerging tourist destination with a variety of activities to offer. The area is rich in ancient rock art sites and, as a result, has great potential for the development of heritage tourism. Extensive research has been conducted on the rock art in this region. However, the impact of climate change on heritage tourism has not yet been explored. The local community of the Makgabeng area is developing a heritage tourism destination within the region and it is important to determine whether the initiative will be sustainable, especially in the context of climate change threats to the region. In a region such as Makgabeng where the primary attraction is natural heritage tourism rather than cultural, this then poses a severe threat to tourism within the region, especially since most of these attractions are outdoors. Hence, this research project is primarily aimed at determining climate change threats to heritage tourism in the Makgabeng region, South Africa. The research has employed a mixed-method approach consisting of interviews done with various stakeholders within the tourism industry and community members in the Makgabeng region. The other methods used are hard-copy and online questionnaires, TripAdvisor reviews, and the Tourism Climatic Index (TCI). What the research has found is that people do not know that Makgabeng exists, and for those who are aware of its existence they have never visited the region. this is because the area is not being marketed effectively. The TCI scores show that winter is the best time of the year for tourism. Consequently, stakeholders and community members should market the area with this in mind. However, tourists have said they enjoy the weather in the region all year round.
The nineteenth century Matabele settlements on the South African Highveld
(University of the Witwatersrand, Johannesburg, 2023) Van der Merwe, Renier Hendrik; Sadr , Karim; Fowler, Kent
The rise of the Zulu kingdom in KwaZulu-Natal, South Africa, has been a topic of historical research since the 1870s and coincided with increased conflict within the area. The development of the Matabele as a distinct cultural grouping was a gradual process that occurred for decades. Although, initially, only a small group of Khumalo (a northern Nguni clan that formed the elite of the Matabele), they soon started to incorporate the surrounding Sotho/Tswana communities. A clear understanding of their archaeological signatures is needed for Matabele sites to be identified on the landscape. No clear archaeological signature has yet been developed for the Matabele. Therefore, this project aims to describe the organisation of the Matabele military settlements and determine how they evolved during the migration from KwaZulu-Natal to southern Zimbabwe. A settlement organisational model was created that determined that the Matabele and Zulu had a similar settlement organisation, with important differences that allow for individual identification of each group’s settlement. Furthermore, the Matabele utilised perishable material in the construction of the settlement, with no mention of the use of stone found within the historical accounts. Consequently, a difference existed between settlements constructed by Matabele viewed as Nguni and those not regarded as Nguni. This Nguni-non-Nguni divide was also reflected in the presence or absence of the Nguni culture among the inhabitants. This model was then used to develop a Matabele settlement signature that could be used to locate these settlements on the landscape via the use of satellite and multispectral satellite images. A satellite images-based survey was then undertaken to find potential Matabele settlements between Zeerust and Millvale, with 667 potential sites being identified. With the identification of these sites, archaeological excavations can be conducted to develop a clearer understanding of the Matabele. As our knowledge of the Matabele improves, it will allow for a more detailed examination of the northern Nguni as a wider cultural grouping.
A GIS framework for the integrated conceptualisation, analysis and visualisation of Gauteng's complex historic and contemporary post-mining urban landscape
(University of the Witwatersrand, Johannesburg, 2023) Khanyile, Samkelisiwe; Esterhuysen, Amanda; Kelso, Clare
This research study applies assemblage theory as a philosophical lens. It proposes a framework for integrating contemporary and historical landscape characteristics of post-mining and urban landscapes for an integrated conceptualisation, mapping, and analysis of Gauteng, South Africa. The study utilises a mixed methods approach, incorporating spatial and non-spatial (literature and survey) data of varying formats to identify landscape characteristics. Additionally, it applies three multicriteria decision analysis (MCDA) and GIS mapping techniques, employing a simplified rationale to keep its complexity low. Descriptive and inferential statistics were used to analyse the quantitative data, while the qualitative data was analysed using a thematic analysis. The literature and survey analysis findings were used to inform the development of a framework demonstrating the integration of Gauteng's post-mining and urban landscape characteristics using a fuzzy overlay, weighted overlay and random forest classification, along with an accuracy assessment of the mapped results. Based on the proposed framework, the mapped results' performance was evaluated through four methods: confusion error matrix, cross-evaluation, areal coverage comparison, and an image differencing assessment. The literature and survey analysis findings, used to inform the framework, reveal that the two landscapes consist of an assemblage of characteristics and highlight differences in the characterisation of post- mining and urban landscapes. Distinctions were also apparent between literature-derived characteristics and those identified from local experts. The local expert-derived characteristics demonstrate context- specific characteristics of Gauteng's post-mining and urban landscape. At the same time, those based on the literature emphasise a more distinct and separate portrayal of post-mining and urban landscape characteristics (pages 115-116). The characteristics identified from local experts were less conservative (pages 117-118). They included urban-related characteristics in the description of post-mining landscapes and mining-related characteristics in the description of urban landscapes, presenting some similarities in the characterisation of these two landscapes in Gauteng. Moreover, the findings from local experts also revealed that literature and other written or mapped work informed most definitions of post-mining and urban landscapes. The framework for integrating landscape characteristics (pages 121-123) was spatially represented through the three mapping methods, visually demonstrating several findings providing insight into the Gauteng landscape's uniqueness. First, it demonstrates that the differences in the characterisation of these landscapes also impact how they are spatially represented. The maps of post-mining and urban landscape characteristics based on the literature presented a similar pattern to the traditional mapping of mining and urban landscapes in Gauteng. These mapping techniques show the highest values across the mining belt and at the province's core. These findings highlight the influence of literature on the representation of these two landscapes, which is consistent with local experts' reports. In all three mapping methods, the maps generated from local expert characterisations of post-mining and urban landscapes presented a larger spatial footprint than those based on literature-derived characteristics. This distinction was attributed to incorporating additional post-mining and urban landscape characteristics in the maps based on expert input and applying the three mapping techniques - using representation methods not commonly used in mapping these landscapes. Second, the integrated maps of post-mining and urban landscape characteristics suggested a variance in the presence of post-mining and urban landscape characteristics across the province in the maps generated using fuzzy and weighted overlay techniques. This indicates that some parts of the province have a higher or lower presence of post-mining or urban characteristics (pages 125-132). These findings were visible in the maps generated from literature and local experts, indicating the diversity of both landscapes and the co-existence of post-mining and urban landscape characteristics in the local expert maps. This implies an intricate relationship between these landscapes, challenging the idea of them being strictly separate, as indicated in maps presenting characteristics identified from the literature. Furthermore, a closer inspection of the areas showing the intersection between post-mining and urban landscape characteristics also points towards the porosity of boundaries of these two landscapes and alevel of spatial overlap, organisation and arrangement, which are prevalent at varying levels (pages 164- 168). Third, the maps generated using literature-derived characteristics achieved higher accuracy scores, attributed to using reference data traditionally used to map the two landscapes under investigation. This reference data only comprised classes that characterised the physical mining and urban classes, consistent with those identified in the literature. Consequently, it lacked additional factors characterising the post-mining and urban landscape identified from local experts. The fuzzy overlay maps informed by literature demonstrated an accuracy exceeding 70% for post-mining and urban landscape characteristics. In comparison, those reported by local experts scored 64. The weighted overlay and random forest classification resulted in accuracy rates exceeding 50% for post-mining landscape characteristics maps, regardless of whether literature or expert-derived characteristics were used. Additionally, urban landscape characteristics maps achieved an accuracy of over 76%, regardless of the characteristics used to inform the mapping. These findings were attributed to the different mapping techniques employed, with fuzzy and weighted overlay using a gradual range scale, while random forest classification employed a binary scale. This highlights how different mapping methods affect the representation of space. Additionally, it demonstrates the versatility of these mapping techniques in mapping complex spaces such as post-mining and urban landscapes. In this study, the fuzzy overlay accuracies exceeded 60% for all maps and emerged as the most suitable choice for integrating landscape characteristics due to its ability to represent blurred and porous boundaries between Gauteng's post- mining and urban landscapes. In conclusion, the study challenges the notion of post-mining and urban landscapes as distinct landscapes, emphasising the importance of considering the varying levels of spatial intersection between these two landscapes. With the proposed framework and the alternative representation of these landscapes, including contextual information, this research provides insights into new conceptualisations of urban, post-mining landscapes and mineralised urbanisations as assemblages of different landscapes and characteristics with porous boundaries. This enables a better understanding of Gauteng's post-mining and urban landscapes, which could benefit the representation, communication and management of these landscapes. Recognising the potential applications and limitations of frameworks such as the one developed for this study, the high-level recommendation arising from this study suggests a need for ongoing research into the contextual representation of landscapes and their characteristics. This can be achieved by incorporating input from communities, conducting research on quantifying intangible landscape characteristics and developing tools that facilitate the automation and alignment of such data with development plans.
Estimating rooftop solar energy potential using spatial radiation models and thermal remote sensing: The case of Witwatersrand University
(University of the Witwatersrand, Johannesburg, 2023) Ndemera, Rudo Hilda; Adem, Ali K.; Adam, Elhadi
The main purpose of this research was to estimate the University of Witwatersrand building’s rooftop solar energy potential using the GIS-based solar Area Solar Radiation (ASR) analyst upward hemispherical view shed algorithm. The two major datasets used in this research for rooftop solar energy potential modelling are building footprint data and the Digital Surface Model. Building footprint data, specifically rooftop area was extracted using machine learning CNTK unified toolkit and deep neural networks. The data was presented as individual polygon shape files for each building. The high-resolution Digital Surface Model imagery was sourced from the Advanced Land Observation Satellite. Pre-processing of the imagery was done for atmospheric correction. The DSM was then used in the Area Solar Radiation model to create an upward view shed for every point on the study area which is essential for computing solar radiation maps. The efficiency of using this algorithm is that it considers the shading effects caused by surrounding topography and surrounding man-made features, alterations in the azimuth angle and the position of the sun. Apart from the incoming solar radiation reaching the rooftops, the elevation and orientation of the rooftop cells limit the solar panel tilt angle and intensity of the incoming solar radiation, respectively. These factors were used in setting the suitability criteria together with solar radiation for the identification of suitable rooftop cells in this research. The relationship between land surface temperature and solar radiation values was assessed to determine if it can be used as an indicator for solar panel efficiency. Results from this research indicate that the University of Witwatersrand receives high levels of incoming solar radiation and has a high solar energy rooftop generation capacity that can meet the energy demand on campus. To improve accuracy of the research results, a drone could have been used to measure insolation across the study area to improve the spatial resolution. However, this was not possible due to various restrictions.
Assessment of the impact of load shedding on the households of Alexandra, Johannesburg, South Africa
(University of the Witwatersrand, Johannesburg, 2023) Mbatha, Cebolethu; Kubanza, Nzalalemba Serge
In South Africa, persistent challenges in the electricity sector have been noted. This study emphasizes that having access to electricity is insufficient; the reliability of its supply is crucial,especially given prolonged power outages faced by a significant portion of the population. In Alexandra Township at two residential areas, 16th Avenue and East Bank, the research used a mixed-method approach, involving questionnaires for 100 households and 20 local businesses, and semi-structured interviews with representatives from the local city authority. Results indicated substantial disruptions to daily lives and operations. These disruptions adversely affected critical social services, hindering operations in essential infrastructures like water supply systems, hospitals, education institutions, and telecommunication systems. The study identifies illegal electricity connections, infrastructure loss, and political interference as perceived major causes of successive power outages in Alexandra. It highlights the worsening nature of load shedding, making it a significant political issue in South Africa, reflecting hardships households and businesses face. The paper recommends governmental subsidies for alternative energy appliances and more favorable electricity tariff rates for households and small businesses to alleviate demand during peak periods. The findings offer valuable insights for policymakers and the South African electricity utility in analyzing trade-offs between negative welfare effects and costs of reducing power outages
Palynological insights into an 11,700-year sequence of vegetation change in mashishing, Mpumalanga, northeastern South Africa
(University of the Witwatersrand, Johannesburg, 2023) Olatoyan, Jerry O.; Schoeman, Alex; Neumann, Frank; Sievers, Christine; Orijemie, Emuobosa; Evans, Mary
In this thesis, the issue of distinguishing anthropogenic and climatic drivers of vegetation change was explored through the analysis of pollen, phytoliths and microcharcoal in core sediment records from Mashishing Fen in the Thaba Chweu Municipality, Mpumalanga province, northeastern South Africa, that date from ca. 11.2 – 11.7 ka BP to the present. In southern Africa, generally, the distinction between the contributions of anthropogenic and climatic factors to vegetation changes poses a complex challenge in palaeoenvironmental research. This difficulty often arises due to limited, well-dated palaeoenvironmental sequences suitable for correlations between archaeological and palaeoecological records. For the last 2000 years, there has been a scarcity of direct evidence for farming, such as grains and other domesticated plants, and pastoralism. A further difficulty is that some plant taxa may be indicators for intense droughts but also signify anthropogenic disturbances. At the centre of the thesis are three papers. The first comprises a synthesis of existing literature of archaeobotanical evidence that was done to evaluate the relationship between climate, anthropogenic activities, and vegetation change during the first millennium CE in southern Africa. I focussed on this context in the paper because it is a time in which the arrival of pastoralism and farming in the region makes it the most likely period during which distinct anthropogenic vegetation change occurred. The published data demonstrates that microfossil assemblages are potential indicators of anthropogenic activities of pre-European pastoralists and farmers of the region, with patterns including a decline in tree pollen and increases in microcharcoal, spores of coprophilous fungi, open land/disturbance indicators, and ruderal species. The second paper addresses some of the limitations of palynology as a method. A modern pollen- and phytolith-vegetation study was conducted on surface sediment samples linked to the botanical survey of five vegetation survey plots at and around Mashishing Fen to investigate the relationships between the modern pollen and phytoliths in the surface samples and the contemporary vegetation within the area. The results support the accepted view that pollen and phytoliths often do not track similar vegetation signals. The modern pollen assemblages clearly track forest and wetland vegetation, and the modern phytolith assemblages reflect grassland vegetation in the area. The study confirmed that differential phytolith and pollen production, dispersal and preservation substantially influence the proxy records and that combining phytolith and pollen data provides a more accurate basis for plant fossil interpretations in palaeoenvironmental studies. The results of this paper constrained my interpretation of the pollen data used in the third paper. Finally, pollen, spores and microcharcoal data from the core sediment records from Mashishing Fen (formerly the Lydenburg Fen) provide palaeoenvironmental records for approximately the last 11,2 to 11,7 ka years–most of the Holocene. The data is interpreted through the patterns identified in the first paper, including potential indicators of anthropogenic activities. The data of the earlier period provide a backdrop to possible anthropogenic change in the first millennium CE; the extended data illustrate paleoenvironmental changes that took place in a region occupied by hunter-gatherers but predate any possible anthropogenic influences by pastoralists or farmers. The core data suggests that the early Holocene began with moist and warm conditions that were followed by fluctuations between wet and dry conditions during the mid-Holocene and the decline of trees with the dominance of open-land indicators during the later Holocene, thereby providing the basis for correlating the palaeoecological records with the archaeological records in the region
Mapping and monitoring land transformation of Boane district, Mozambique (1980 – 2020), using remote sensing
(University of the Witwatersrand, Johannesburg, 2023) Dengo, Claudio Antonio; Atif, Iqra; Adam, Elhadi
Although natural and environmental factors play a significant role in land transformation, human actions dominate. Therefore, to better understand the present land uses and predict the future, accurate information describing the nature and extent of changes over time is necessary and critical, especially for developing countries. It is estimated that these countries will account for 50% of the world's population growth in the next few years. Hence, this research was an attempt to assess and monitor land cover changes in Boane, Mozambique, over the past 40 years and predict what to expect in the next 30 years. This district has been challenged by a fast-growing population and land use dynamic, with quantitative information, driving forces and impacts remaining unknown. Through a supervised process in a cloud base Google Earth Engine platform, a set of five Landsat images at ten-year intervals were classified using a random forest algorithm. Seven land classes, i.e., agriculture, forest, built-up, barren, rock, wetland and water bodies, were extracted and compared through a pixel-by-pixel process as one of the most precise and accurate methods in remote sensing and geographic information system applications. The results indicate an active alternate between all land classes, with significant changes observed within agriculture, forest and build-up classes. As it is, while agriculture (-26.1%) and forest (-21.4%) showed a continuously decreasing pattern, build-up class (45.8%) increased tremendously. Consequently, over 69% of the forest area and 59% of the agricultural area shifted into build-up, i.e., was degraded or destroyed. Similarly, the conversion of barren land area (57.2%) and rock area (47.3%) into build-up indicates that those areas were cleaned. The overall classification accuracy averaged 90% and a kappa coefficient of 0.8779 were obtained. The CA-Markov model, used to assess future land uses, indicates that build-up will continue to increase significantly, covering 60% of the total area. From this finding, the land cover situation in the next 30 years will be critical if no action is taken to stop this uncontrolled urban sprawl. An adequate land use plan must be drawn, clearly indicating the locations for different activities and actions for implementation.
Examining the remaining Rock Art at Linton, Eastern Cape, and its relationship with the Linton Panel at the Iziko South African Museum in Cape Town
(University of the Witwatersrand, Johannesburg, 2023) Oster, Sandee Michelle; Pearce, David
The Linton panel has been the subject of great awe for many decades. It has been displayed in various exhibits worldwide and the subject of multiple research publications. However, its history and origin are not nearly as well understood as once believed, as a large part of its past has been omitted or forgotten. In this dissertation the images of not only the Linton panel are discussed, but those that remain in the shelter from whence it came are brought out of obscurity. How the panel came to be where it is today and the images’ relationship with the shelter and the remaining paintings are examined. Lastly, a forgotten piece of the shelter, a second panel, will be examined in greater detail than ever before: how it fell into relative obscurity and what its images tell us about the Linton shelter and its artists’ beliefs and purposes.
Pandemics and Heritage: understanding the impact of the Covid-19 pandemic on Archaeotourism in South Africa
(University of the Witwatersrand, Johannesburg, 2023) Eswaran, Nithya
The project explores the impact of the Covid-19 pandemic on archaeotourism at three public visitation sites in South Africa. According to the 2021 UNESCO report on the impact of Covid- 19 on heritage tourism, visitors to Africa decreased by 71% in 2020. The drop significantly impacted the revenue of the continent (UNESCO 2021). This research focuses on assessing the effects of the COVID-19 pandemic locally by examining two UNESCO World Heritage sites: the Sterkfontein Caves in the Cradle of Humankind, Gauteng Province, and Main Caves in Giant’s Castle Game Reserve, KwaZulu-Natal Province. The third study site is the Origins Centre Museum at the University of Witwatersrand in Johannesburg. These sites are open to tourists for guided tours. Quantitative data from Kruger National Park is collated to analyse the pandemic's influence on public, nature-based sites for comparison to culture sites
Monitoring and evaluating urban land use land cover change using machine learning classification techniques: a case study of Polokwane municipality
(University of the Witwatersrand, Johannesburg, 2023) Funani, Tshivhase; Mhangara, Paida
Remote sensing is one of the tools which is very important to produce Land use and land cover maps through the process of image classification. Image classification requires quality multispectral imagery and secondary data, a precise classification technique, and user experience skill. Remote sensing and GIS were used to identify and map land-use/land-cover in the study region. Big Data issues arise when classifying a huge number of satellite images and features, which is a very intensive process. This study primarily uses GEE to evaluate the two classifiers, Support Vector Machine, and gradient boosting, using multi-temporal Landsat-8 images, and to assess their performance while accounting for the impact of data dimension, sample size, and quality. Land use/Landcover (LULC) classification, accuracy assessment, and landscape metrics comprise this study. Gradient Tree Boost and SVM algorithms were used in 2008, 2013, 2017, and 2022. Google Earth Engine was used for supervised classification. The results of change detection showed that urbanization has occurred and most of the encroachments were on agricultural land. In this study, XG boost, and support vector machine (SVM)) were used and compared for image classification to oversight spatio-temporal land use changes in Polokwane Municipality. The Google Earth Engine has been utilized to pre-process the Landsat imagery, and then upload it for classification. Each classification method was evaluated using field observations and high-resolution Google Earth imagery. LULC changes were assessed, utilizing Geographic Information System (GIS) techniques, as well as the dynamics of change in LULCC were analysed using landscape matrix analysis over the last 15 years in four different periods: 2008–2013, 2018 and 2022. The results showed that XGBoost performed better than SVM both in overall accuracies and Kappa statistics as well as F-scores and the ratio of Z-score. The overall accuracy of gradient boosting in 2008 was 0.82, while SVM showed results of 0.82 overall accuracy and kappa statistics of 0.69. The average F-score for SVM in 2008 was from 0.58- 1.00, in 2013 an average of 0.86-0.97, and in 2022 it was 0.76. Z values were not statistically significant as all values were below the z score of 1.96. The ratios for the two classifiers were also taken to know which classifier performs the best. The results showed 212:212 which indicates that during 2008 SVM and XG boost performed the same way as they classified the same number of cases. During 2013 the ratio was 345:312 which shows that XGBoost performed better than SVM. The results of 2017 show 374:316 which shows that XGBoost performed better than SVM. Lastly, in 2022 the ratio was 298:277 which shows that XGBoost performed better than SVM. Overall zscores result show that XGBoost performs better than SVM. Overall, this study offers useful insight into LULC changes that might aid shareholders and decision makers in making informed decisions about controlling land use changes and urban growth
Assessing the effectiveness of wetlands in the Krugersdorp Game Reserve in attenuating pollution from mines on the West Rand, South Africa
(University of the Witwatersrand, Johannesburg, 2023) Sawuka, Noluthando Thulisile; Evans, Mary; Masindi Khuliso
In South Africa, 48% of the country’s wetlands are critically endangered because of anthropogenic activities. Wetlands are an important part of the landscape and play a critical role including but not limited to improving water quality, habitat provision, and water storage. This research aimed to assess the effectiveness of wetland systemsin attenuating pollution from water discharged from abandoned gold mines in the Krugersdorp Game Reserve (KGR), West Rand. Eight (8) water samples were collected in the study site. Physico-chemical parameters were measured in situ, and chemical parameters were measured in the lab. The measured physico–chemical parameters from the majority of the sampled wetlands exceeded at least one of the stipulated water quality legislations, which included the General Authorization Limit Section 21f and h, 2013; Unit for TWQGR; Mine Health and Safety Act; and WUL wastewater in terms of the recorded pH, total dissolved solids, and salinity variables. Overall, a decreasing trend in pH level was observed from wetlands sampled upstream of the KGR to wetlands sampled downstream of the KGR, with the highest recorded pH level (Alkalinity: 8.9) obtained from the sampled wetland that was closest to the adjacent mining site upstream of theKGR whilst the lowest recorded pH level (Acidity: 3.9) obtained from a wetland sampling point that was further from the adjoining mine and downstream in the KGR. A weak and positive correlation (r=0.040) was obtained between the measured total dissolved solids and pH levels from the sampled wetlands, indicating minimal spatial variability. However, a strong positive correlation (r=0.999, Correlation is significant at the 0.01 level) was obtained between the measured total dissolved solids and salinity from the sampled wetlands. At least one of the limits stipulated by the water quality legislation was exceeded in terms of the analysed inorganic constituents from the sampled wetlands. The dominant ions recorded in the wetlands in increasing order are F, K, Cl, Mg, Na, Ca, and SO4. Mn and Si were the dominant metal concentrations recorded in most wetlands, with the former also showing exceedances when compared to the stipulated water quality guidelines. The recorded data from the measured physico–chemical parameters and analysed chemical variables indicated poor water quality in wetlands sampled downstream of the KGR and upstream of the KGR. Stringent measures in water quality monitoring need to be implemented to mitigate the environmental impacts associated with wastewater discharge into the receiving environment.
Peat dynamics in the Angolan Highlands
(University of the Witwatersrand, Johannesburg, 2023-03) Lourenco, Mauro Cesar; Woodborne, Stephan; Fitchett, Jennifer
The Angolan Highlands is a war stricken, threatened, and under-studied area. The region is hydrologically and ecologically important and supports extensive tropical peatland deposits. Peatland preservation has been acknowledged to address climate change, is sensitive to drought and fire, and is directly influenced by vegetation and hydrological conditions. However, little research has been conducted in the Angolan Highlands. This study addresses gaps in the literature through four key contributions. The first is a critical review of peat definitions: the implications of disparate definitions are detailed, and a new proposed definition for peatlands in the interest of climate science is provided. The second is the first map of peatland extent in the Angolan Highlands, containing details on the age and growth dynamics. The study presents a conservative estimate of peatland extent that is much larger than previously estimated for Angola and is a crucial first step in facilitating the preservation of this deposit. The third contribution is the first historical assessment of drought and vegetation response in the region. This contains a 40-year drought and 20-year vegetation history, demonstrating that drought occurrence is increasing and there is a strong relationship between precipitation and the peatland vegetation region. The fourth contribution is the first assessment of the contemporary (2001-2020) fire regime of these peatlands, and reveals that among all land cover classes, peatlands burn more frequently and at a higher proportion. Investigation into the peat dynamics of the Angolan Highlands indicate that they have critical importance and are naturally resistant to both droughts and fire. Failure to preserve these deposits will have direct implications on the communities, environment, and surrounding areas.
Climate Variability and Asset Adaptation of Small-scale Farmers in Zimbabwe's Gokwe South District:A Search for Knowledge Integration Approach
(University of the Witwatersrand, Johannesburg, 2023-05) Chatsiwa, Jaison; Simatele, Mulala Danny
Globally, climate change and variability threaten food production and security for an unforeseeable future leaving millions of people vulnerable to hunger and malnutrition related diseases. Climatic models are projecting that Zimbabwe’s climate will be hanging drastically with a high possibility of experiencing extreme weather patterns impacting the livelihoods of small-scale farmers who rely on rain-fed agriculture for their livelihoods. This study aims to investigate the role of asset portfolios in reducing the climate vulnerability of small-scale farmers of Gokwe South in Zimbabwe. Zimbabwe’s agricultural production both crop and livestock production has been negatively impacted due to the dwindling rainfall and increase in temperature and climate related risks and disasters. The quality and quantity of asset portfolios determine the adaptive strategies and their success against the challenges of climate variability. Despite these effects, small-scale farmers in the Gokwe South district are using their asset portfolios to increase their adaptive capacity and resilience to fight against the challenges of climate variability. Therefore, this thesis revealed a paradigm shift from asset vulnerability to pro-poor asset adaptation. The paradigm shift crafted the ‘Theory of Change’ which is useful for climate variability adaptation strategies in the Gokwe South district as the small-scale farmers change from asset vulnerability to asset adaptation. The Theory of Change encourages contextual analysis of the area and theme under study. A Theory of Change is a method that explains how a given intervention, or set of interventions, is expected to lead to specific development change, drawing on a causal analysis based on available evidence. This study used the Participatory Climate Change Adaptation Appraisal (PCCAA) as the primary data collection tool and the Participatory Rural Appraisal (PRA) known as the emancipatory methodology, to collect data in rural areas. A mixed methodological approach involving qualitative and quantitative was applied. We used thematic content analysis to analyse qualitative data collected during the data collection exercise. During the study period, computer-Aided Qualitative Data Software was used to store data in a sorted manner. The parametric variables were coded using the Predictive Analytic Software. This enabled to performance of statistical analysis and obtaining descriptive statistical outcomes were obtained. The assessment of the effect of the factors on climate adaptation strategies was done through the Likert scale. Indigenous knowledge remained widely used as a source of climate knowledge in the Gokwe South district. The research results showed that indigenous knowledge (IK) is unpredictable, productive assets and adaptive assets are inadequate, technoscience and institutional support are poor support to implement viable adaptation strategies is lacking, and poor distribution and dissemination of climate and weather information to small-scale farmers in the Gokwe South district is poor and asset portfolios and asset mix is poor. The available asset portfolios determine the adaptation strategies used in the Gokwe South district. Results show that climate vulnerability varies spatially and temporally across the Gokwe South district. The studied five constituencies for the Gokwe district have a mean vulnerability index of 3.04 with the highest index being 5 as being well adapted. Sengwa and Mapfungabutsi are highly vulnerable to the vagaries of climate variability in the Gokwe South district. The researchers recommend strong institutional support from the government. The fact that small-scale farmers should integrate their IK and modern science climate knowledge small-scale farmers in the Gokwe South district should adopt proactive or anticipatory adaptation, government climate-smart agricultural policies, and a bottom-up approach to climate variability. The quality and quantity of asset portfolios are key resources affecting the level of vulnerability to climate variability. The asset mix was seen to be significant in reducing the vulnerability of small-scale farmers in Sengwa and Mapfungabutsi, constituencies worst affected due to poor asset endowment of farmers in the Gokwe South district. The results have shown that the financial asset is the most important asset affecting vulnerability because it can be converted into other assets through buying. Weak institutional intervention renders many small-scale farmers helpless to climate variability, and the government is not fully supporting small-scale farmers to increase their adaptive capacity and resilience.
The political geography of hemp Cannabis in South Africa: A development critique
(University of the Witwatersrand, Johannesburg, 2023-06) Moore, Wendell; Wafer, A; Mnwana, S
The discourse on Cannabis that is generally understood in the public domain, revolves mostly around its recreational uses and more recently its medicinal potential. The plants industrial usages and overall worth to society are often framed in relation to these more popular parts of Cannabis. The study focuses its attention on hemp Cannabis to tell a different story but acknowledges that all the uses of Cannabis are interlinked. Using an extensive desktop analysis, Cannabis webinars and conferences, as well as autoethnography, the thesis shows that there is in fact more to the plant than what first meets the eye. It especially illuminates two important dimensions of Cannabis that are often overlooked when discussing the plant. Firstly, by its nature Cannabis is political, which is deeply embedded in how the plant is understood in the geographic diaspora of the Global South. Secondly, it shows that any serious social scientific analysis of contemporary Cannabis development must think through how the ways of knowing, Produced during prohibition, will become a part of the plant’s future. This thesis therefore argues for an appraisal and maintenance of the historical resistances of Cannabis used prior to legalization, if its development in the legal era is to be successful. To be sure, such innovative and alternative models of practical development should become a standard part of the geographies of all work economies. Moreover, making use of these forms of resistance is not about Cannabis gaining the approval from ‘the market’. In fact, the skills learnt while labouring for Cannabis, when it was prohibited, has become such a permanent feature of its development that liberal democratic consent is not an option. Therefore, the thesis proposes that Cannabis development delink from the prohibition narratives inscribed onto the plant. It continues by showing that the current medicalisation of Cannabis only updates gatekeeping models. Hence, an agrarian alternative was suggested that consolidates all the uses of Cannabis without undermining any one part of the plant. Lastly, the thesis documents the possibilities of gaining access into the industry for black people, the poor working class and women. What it argues is that ownership, just employment and leadership of Cannabis industries in South Africa must be repurposed so that ordinary people can also play a part in making sure the plants contemporary development is truly sustainable. Taken together, this is the critique of development that the political geography of hemp Cannabis in South Africa reveals.
The political geography of hemp Cannabis in South Africa: A development critique
(University of the Witwatersrand, Johannesburg, 2023-06) Moore, Wendell; Mnwana, Sonwabile; Wafer, Alex
The discourse on Cannabis that is generally understood in the public domain, revolves mostly around its recreational uses and more recently its medicinal potential. The plants industrial usages and overall worth to society are often framed in relation to these more popular parts of Cannabis. The study focuses its attention on hemp Cannabis to tell a different story but acknowledges that all the uses of Cannabis are interlinked. Using an extensive desktop analysis, Cannabis webinars and conferences, as well as autoethnography, the thesis shows that there is in fact more to the plant than what first meets the eye. It especially illuminates two important dimensions of Cannabis that are often overlooked when discussing the plant. Firstly, by its nature Cannabis is political, which is deeply embedded in how the plant is understood in the geographic diaspora of the Global South. Secondly, it shows that any serious social scientific analysis of contemporary Cannabis development must think through how the ways of knowing, produced during prohibition, will become a part of the plant’s future. This thesis therefore argues for an appraisal and maintenance of the historical resistances of Cannabis used prior to legalization, if its development in the legal era is to be successful. To be sure, such innovative and alternative models of practical development should become a standard part of the geographies of all work economies. Moreover, making use of these forms of resistance is not about Cannabis gaining the approval from ‘the market’. In fact, the skills learnt while labouring for Cannabis, when it was prohibited, has become such a permanent feature of its development that liberal democratic consent is not an option. Therefore, the thesis proposes that Cannabis development delink from the prohibition narratives inscribed onto the plant. It continues by showing that the current medicalisation of Cannabis only updates gatekeeping models. Hence, an agrarian alternative was suggested that consolidates all the uses of Cannabis without undermining any one part of the plant. Lastly, the thesis documents the possibilities of gaining access into the industry for black people, the poor working class and women. What it argues is that ownership, just employment and leadership of Cannabis industries in South Africa must be repurposed so that ordinary people can also play a part in making sure the plants contemporary development is truly sustainable. Taken together, this is the critique of development that the political geography of hemp Cannabis in South Africa reveals.
Exploring Spatio-Temporal Climate Dynamics over Central Southern Africa: A Cross Border Analysis
(University of the Witwatersrand, Johannesburg, 2023-07) Welff, Megan; Fitchett, Jennifer; Esterhuysen, Amanda
Understanding the diverse nature of climate dynamics in southern Africa is imperative in the face of climate change. Ground-based meteorological stations provide high-resolution climate data that can be used to investigate and analyse climate in detail. However, southern African countries monitor and manage meteorological stations independently which presents various challenges when attempting cross-border studies. While there are many meteorological-station-based climate studies conducted for South Africa or Botswana, there are few that combine meteorological datasets from both these countries to investigate climate dynamics across political boundaries. In this study, meteorological data from Botswana Meteorological Services and the South African Weather Service spanning 1912-2019 is pre-processed, cleaned and combined to produce a cross-border dataset. A total of 44 stations covers the Gauteng and North West provinces in South Africa and the southern, Kweneng, Kgatleng, South-east and Kgalagadi districts of Botswana. The combined cross-border dataset includes the average monthly summer, winter and annual rainfall (RS, RW and RA respectively) and the average monthly minimum and maximum summer, winter and annual temperatures (TSmin, TSmax, TWmin, TWmax, TAmin and TAmax respectively). From the linear regression analysis, an overall increasing trend for temperature is identified barring two stations (TSmin and TAmin for Mahalapye Met station, and TWmin for Vaalharts). Additionally, for rainfall there is a significant decreasing trend identified. Lastly, the spatial variability of the region is determined using an Inverse Distance Weighted interpolation in the GIS Software, ArcMap, to interpolate between stations. From this a west to east reduction in rainfall and a north-western to south-eastern decreasing temperature gradient is identified across the study region.
Integration of Sustainable Development Principles and Climate Change Adaptation Measures in Energy Optimization in Gold Mining in South Africa
(University of the Witwatersrand, Johannesburg, 2023-08) Nadunga, Irene; Simatele, Mulala Danny
South Africa located in the sub-Saharan African region and being a mining-intense country, is reported to be affected by extreme weather events which are increasing the country’s vulnerability to climate change impacts and therefore reducing the chances of achieving sustainable development. In light of this, mining companies are being pressured to make strong commitments towards implementation of sustainable development principles for sustainable mining. This study therefore aimed at investigating how sustainable development principles and climate change adaptation measures are interlinked and structured; and embedded in a gold mining company’s policies and strategies, in an effort to build the mining operations’ adaptive capacity and resilience against the impacts of climate change and achieve energy optimization. The challenges that can potentially prevent the effective integration of the sustainability principles and adaptation measures were also explored. Using a case study approach, this study was centered on the gold mining operations located within the Witwatersrand Basin of South Africa. Research data was collected from multiple sources, therefore employing a mixed method approach by applying the concurrent triangulation technique. Different analytical tools of policy, content and inductive data analysis, and descriptive statistical data analysis were applied. The empirical evidence shows that the gold mining operations are faced with increasing operating costs associated with the increased energy consumption and implementation of costly mining practices in an effort to combat the impacts of extreme weather events caused by climate change. This affirms that a relationship exists between climate change and energy use in gold mining. In an effort to address climate related risks and energy security, gold mining operations are implementing energy efficiency measures and using renewable energy in their energy mix; which measures are seen to integrate sustainability principles, therefore adopted as sustainability adaptation measures. In addition, some mining company policies and strategies are also seen to integrate sustainability principles and adaptation measures, in an effort to guide the mining operations in effectively developing and implementing sustainability adaptation measures, designed to holistically address climate related risks and energy security. This affirms that a relationship exists between sustainable development principles, climate change adaptation measures and energy optimization. This therefore, implies that sustainability principles and adaptation measures can be integrated to form sustainability adaptation measures, and that gold mining companies have the potential to achieve sustainable mining and contribute to sustainable development, particularly achieving SDG 7 and SDG 13.
Traditional Custodians, Sacred Heritage Sites and Tourism Development: A Case Study ofthe Phiphidi Falls in the Limpopo Province of South Africa
(University of the Witwatersrand, Johannesburg, 2023-09) Mabehle, Nhlaluko; Russell, Thembiwe
The way in which intangible heritage should be preserved is a debatable subject, and the question about who should have authority over what happens at sites associated with spiritual values is often a contentious issue. While local communities frequently hold traditional custodianship of the sites, they usually do not have any legal custody. When tourism developments are suggested in impoverished rural communities, whose basic rights could be met by allowing tourism developments to happen, conflicts frequently arise. Traditional custodians tend to want to keep their places of worship sacred while tourism developers would rather promote such sites as touristic products and potential source of income for the community. Fractions can occur within the communities as well. This project investigated community attitudes towards cultural heritage in Limpopo, using the case of Phiphidi Waterfalls, a site earmarked for tourism development, to analyse traditional management systems and to develop a framework for the effective management and preservation of sacred sites. Comparative studies were used to analyse traditional management systems in southern Africa. The main objective is to attain sustainable preservation of intangible heritage without any conflicts between traditional custodians and tourism authorities, and so this project contributes to the larger debate about who should have authority over sacred sites.
Evaluating the spatiotemporal changes of urban wetlands in Klip River wetland, South Africa
(University of the Witwatersrand, Johannesburg, 2023-09) Nxumalo, Nolwazi; Knight, Jasper; Adam, Elhadi
This study assesses the impacts of land use / land cover (LULC) change in an urban wetland over the past 30 years utilizing machine learning and satellite-based techniques. This study looked at LULC distributions in the Klip River wetland in Gauteng, South Africa. The aims and methods used in this study were: (1) to conduct a comprehensive analysis to map and evaluate the effects of LULC changes in the Klip River wetland spanning from 1990 to 2020, employing Landsat datasets at intervals of 10 years, and to quantify both spatial and temporal alterations in urban wetland area. (2) To predict the change in urban wetland area due to specific LULC changes for 2030 and 2040 using the MOLUSCE plugin in QGIS. This model is based on observed LULC including bare soil, built-up area, water, wetland, and other vegetation in the quaternary catchment C22A of the Klip River wetland, using multispectral satellite images obtained from Landsat 5 (1990), Landsat 7 (2000 and 2010) and Landsat 8 OLI (2020). (3) For the results of this study, thematic maps were classified using the Random Forest algorithm in Google Earth Engine. Change maps were produced using QGIS to determine the spatiotemporal changes within the study area. To simulate future LULC for 2030 and 2040, the MOLUSCE plugin in QGIS v2.8.18 was used. The overall accuracies achieved for the classified maps for 1990, 2000, 2010, and 2020 were 85.19%, 89.80%, 84.09%, and 88.12%, respectively. The results indicated a significant decrease in wetland area from 14.82% (6949.39 ha) in 1990 to 5.54% (2759.2 ha) in 2020. The major causes of these changes were the build-up area, which increased from 0.17% (80.36 ha) in 1990 to 45.96% (22 901 ha) in 2020—the projected years 2030 and 2040 achieved a kappa value of 0.71 and 0.61, respectively. The results indicate that built-up areas continue to increase annually, while wetlands will decrease. These LULC transformations posed a severe threat to the wetlands. Hence, proper management of wetland ecosystems is required, and if not implemented soon, the wetland ecosystem will be lost.

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