Electronic Theses and Dissertations (Masters)

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A comparative analysis of mining environmental management programme reports following a change to the one environmental system
(University of the Witwatersrand, Johannesburg, 2022) Mathe, Lebogang; Watson, I.
The mining fraternity has recently seen a shift in terms of environmental requirements under the ambit of the Mineral and Petroleum Resources Development Act 28 of 2002 (MPRDA) to the National Environmental Management Act 107 of 1998 (NEMA). The objective was to ensure a streamlined environmental compliance and to put emphasis on integrated environmental management. The One Environmental System (OES) was introduced which denotes that all environmental related projects or activities, including mining, are regulated through an ambit of one system. NEMA is recognised as an overarching law which provides for co-operative environmental governance; therefore, all environmental related activities are regulated under its ambit and EIA regulations. In this research report, the Environmental Management Programme (EMP) reports and Environmental Authorisations that were issued under the MPRDA and the 2014 NEMA regulations respectively, were analysed using the respective regulations to compare the environmental management measures outlined in the reports to achieve better environmental results. The aim of the research was to assess whether the Environmental Authorisations granted in terms of NEMA reflect better environmental results as compared to those issued under the MPRDA. Better environmental results mean improved management plans with clearer assessment of impacts, more detailed mitigation measures with specific, achievable, relevant and time bound actions that do not pose harmful effects on the environment and communities. A mixed method of analysis was implemented which included a review and comparison of legislation, evaluation and scoring of 20 EMPs (10 submitted under MPRDA and 10 submitted under NEMA) and interviews with key informants, namely competent authorities and the Environmental Assessment Practitioners (EAPs) were conducted to support the findings of the reports. In conclusion, the reports analysed presented a significant improvement and better environmental results under NEMA. The interviews conducted with authorities and the EAPs have also substantiated the observations made in terms of Environmental Management Programme reports and Environmental Authorisations submitted. The findings indicated that there were similarities in the MPRDA and NEMA regulations as 4 | P a g e regards some environmental requirements. However, the MPRDA lacked to outline a detailed description of environmental requirements needed to manage environmental impacts. Thus, applicants provided limited information in terms of the management of impacts. NEMA has provided additional requirements, including baseline environmental information, specialist reports and public participation amongst others; these contributed to improved environmental results. The study revealed that the reports submitted under NEMA provided better environmental management measures as compared to the reports submitted under MPRDA.
An ethnobotanical study of indigenous knowledge of the medicinal plants used by traditional healers in the rural communities of Nkomazi Local Municipality, Mpumalanga province
(University of the Witwatersrand, Johannesburg, 2024) Khoza, Nompendulo; Dukhan, Shalini; Ramalepe, Phillemon; Risenga, Ida
Traditional medicine continues to significantly impact many people’s lives amid all the advancements in modern medicine. Many rural communities in Mpumalanga province depend on indigenous traditional medicines to manage various ailments. The available research on the traditional usage of medicinal plants among rural communities in Mpumalanga is highly fragmented and under-researched. The decline of medicinal plant populations has led stakeholders to take various initiatives to counteract over-exploitation, including cultivation as a viable conservation approach. However, the scientists' inadequate understanding of the acceptance of cultivated medicinal plants by traditional healers is one of the issues contributing to the failure of medicinal plant cultivation programs. Consequently, this study aimed to document medicinal plants utilised by the Nkomazi Local Municipality's traditional healers and assess opportunities and constraints for medicinal plant conservation in the Nkomazi Local Municipality. The ethnobotanical data was obtained through semi-structured questionnaires and guided field walks with traditional healers. Individual interviews were conducted with ten traditional healers from eight villages across Nkomazi during field visits between July 2021 and February 2022. The study employed qualitative and quantitative approaches to understand traditional healers' perspectives concerning the ethnobotanical significance and medicinal plant conservation. The study found that the indigenous knowledge of medicinal plants in the Nkomazi Local Municipality is diverse, encompassing 111 species from 59 different families employed to treat 70 ailments. Most of the reported medicinal plants for this study are of Least Concern. Additionally, the top fourteen most reported species in the Nkomazi Local Municipality included commercially valuable plants such as Psidium guajava, Ricinus communis, Sclerocarya birrea, Aloe ferox, Aloe maculata, Leonotis leonurus, and Moringa oleifera. Most of the Nkomazi Local Municipality's traditional healers did not know about protected plant species and the National Environmental Management Act (NEMA). Traditional healers were aware of the decline in wild populations of medicinal plants, which they attributed to various factors such as overharvesting. Diviner’s and herbalist perception of using cultivated plants did not differ significantly (𝜒2=0.4762, df=1, P= 0. 490). The study provided a comprehensive inventory of medicinal plants utilised by Nkomazi traditional healers and essential data for future assessments of the use local use of indigenous medicinal plants.
Assessing habitat selection of grassland rodents in the Cradle of Humankind
(University of the Witwatersrand, Johannesburg, 2024) Pinto, Catiuscia-Jade; Mackay, Megan; Pillay, Neville
Habitat selection is a decision-making process undertaken by animals to select an appropriate environment suitable for fulfilling their survival and reproductive needs. These decisions are driven by a complex of biotic and abiotic factors. Habitat selection relies on how an animal interacts with its environment and is species-specific. The vegetation structure and composition influence how smaller animals, such as rodents, obtain food and cover, and are thus critical for their survival. The aim of my study was to assess the population demography and habitat selection of nocturnal rodents in two grassland sites located within the Cradle of Humankind Nature Reserve, Krugersdorp, Gauteng Province, South Africa. I obtained rodent data using Capture-Mark-Recapture (CMR) methods, and vegetation data were obtained through randomised quadrate sampling. The following six rodent species were sampled, Gerbilliscus leucogaster, Lemniscomys rosalia, Mastomys coucha, Micaelamys namaquensis, Mus minutoides and Otomys angoniensis. Rodent abundance differed between summer and winter, with winter showing a higher abundance, but richness and diversity indices did not differ significantly between sites or seasons. The three most common species, G. leucogaster, M. coucha and O. angoniensis, were selected for further population demography analyses. The demography of G. leucogaster, was mostly associated with the season since seasonal fluctuations were observed in their population size (higher in summer), reproductive activity (more active in summer) and body condition (higher in winter). Mastomys coucha was the most abundant species in the study, since it had the highest number of sampled individuals in both summer and winter, although its demography was not influenced by external factors (e.g.,, season, vegetation height, vegetation cover) recorded in both summer and winter. Otomys angoniensis had a positive relationship with vegetation height and rodents’ body condition. The three species were able to coexist with one another due to differences in foraging strategies, reproductive strategies, spatial and dietary partitioning, which help to facilitate habitat selection and illustrate that habitat selection is species specific. Key words: Rodents, habitat selection, Gerbilliscus leucogaster, Mastomys couch
Eco-art for a transformative climate culture
(University of the Witwatersrand, Johannesburg, 2022) Warrington-Coetzee, Hannelie; Voge, Coleen; Manderson, Lenore
Human”‘development” since the industrial revolution has unequivocally attributed to a code red of climate disasters, according to the recent IPCC Sixth Assessment Report of the Intergovernmental Panel on Climate Change report (IPCC, 2022a). To selectively unlearn or de-grow the unsustainable industrial culture crisis, humanity needs seriously to consider and act to transform (e.g., through ecocitizenship) in support of governments, scientists, and other civic actions in our journey to sustainable futures. Using a transdisciplinary praxis approach, artists can provide various forms of transformative possibilities, including transgressive interventions at a grassroots level, deliberately designed to provoke and inspire change. This research interrogates how eco-art deeply engages audiences to identify the key characteristics of such potentially radically transformative artworks. Humans have a narrowing window to transform our relationship to the Earth’s resources and reverse or slow temperature rise. The ‘near term’ (2022 – 2030) will determine and define the extent of various climate transformation pathways (IPCC, 2022, p. 7). Relational eco-art creates spaces for meaningful dialogue to design opportunities for transcendence to ecological citizenship. Art also holds a potential revolutionary connection tool that can unite science and society in incidences of immersion and change to spur further creations and change. These works, which visually articulate diverse types of knowledge, are described in the literature as situated in the fecund middle, a hidden third zone in which components are rhizomatically connected. Here I use fecundity to refer to intellectual productivity. The study aimed to establish which characteristics in eco-art can contribute significantly more to sustainable eco-cultural development and what form and opportunities such transformative interventions manifest. The ways in which artists position their work to contribute to cultural climate change adaptation is interrogated in transdisciplinary praxis. In doing so, I interrogate previously published work of a select group of artists. This is not an inquiry into the methodology of transdisciplinary research, but, drawing on the artists’ praxis, I argue and expand on how the value of collaboration of scholars and artists working in these liminal spaces can reach new audiences. Two datasets are interrogated to analyse the approaches in art related to the environment, one eco-art characteristic derived from the author’s public art praxis, and the second, a broader interrogation of 50 international eco-artworks. By comparing and contrasting the two datasets, characteristics of intentionality, often built into the artworks, were identified. Six key characteristics were isolated, described and further interrogated to discover how they may create opportunities for society to build and foster potential cultural climate change solutions
Evaluation of the JSE’s environmental reporting requirements of South African listed companies
(University of the Witwatersrand, Johannesburg, 2024) Hariram, Viratha; Schwaibold, Ute
Through its mandatory environmental reporting requirements, the Johannesburg Stock Exchange (JSE) plays a pivotal role in the private sector to align to Environmental, Social and Governance frameworks and disclose information of a company’s environmental priorities and performance in addressing areas of concern. While there are attempts to safeguard the environment from damage and degradation, it is unclear if this framework is suitable at appropriately addressing the environmental areas of concern facing South Africa. In order to evaluate the JSE’s environmental requirements on listed companies, this study aimed to identify the local and global environmental priorities via the South African State of Environment Outlook Report (local view), National Development Plan (local view) and Sustainable Development Goals (global view) and thereafter determine if the Global Reporting Initiative, the only set of mandatory environmental requirements of the JSE, was adequately addressing the indicators they outlined. Furthermore, using a scoring system from zero to four, the study evaluated the alignment of ten randomly selected JSE listed companies against the requirements of the Global Reporting Initiative to note their level of adherence and alignment to the South African State of Environment Outlook Report, National Development Plan and Sustainable Development Goals. The results indicate that the Global Reporting Initiative (GRI) covers 73% of environmental priorities discussed in the South African State of Environment Outlook Report, National Development Plan and Sustainable Development Goals. Of the total 74 indicators of environmental concern identified from the three reports, the GRI did not require disclosure for 20 indicators. Only three indicators that were required to be disclosed by the GRI had scored a four on the rating scale due to it being an integrated disclosure that takes into account one or more other related environmental categories. The evaluation of the sampled listed company’s adherence to the GRI via their sustainability reports and integrated annual reports indicated that none of the companies had provided sufficient disclosures to meet the requirements of the GRI. 80% of the sampled listed companies made a strong alignment to the Sustainable Development Goals in their sustainability reports and / or integrated annual reports. A shortcoming of the JSE that was stated by all four sustainability experts interviewed was the lack of enforcement for listed companies to make quality and comprehensive disclosures or accountability expected from listed companies. There is no formal process of review or consequences for listed companies who do not comply.
The Assessment of the Current Geographical Information System (GIS) initiatives in the public enterprises of Swaziland
(University of the Witwatersrand, Johannesburg, 2022) Khumalo, Malungisa Blessing; Adam, Elhadi
There is a growing use of geographic information systems (GIS) within the public sector in many countries. GIS require considerable financial resources and investment in information and communication technology (ICT) and human resources, which are primarily financed by public funds. The growth in adoption is partly influenced by the promising potential of GIS that has been widely discussed in the literature on GIS. The usefulness and application of GIS in aiding decision making and in public policy formulation and implementation have also been widely discussed in the literature on GIS. To examine the effectiveness of GIS in public policy, one has to develop a mechanism for measuring the success achieved by the implementation of GIS in decision making. However, the methodologies for the evaluation of the use of GIS in the public sector are mainly lacking. The aims of this research were to evaluate the effective use of GIS in the public sector in Swaziland. Three organisations were selected, namely the Swaziland Posts and Telecommunications (SPTC), Swaziland Water Services Corporation (SWSC) and Swaziland National Housing Board (SNHB). Like in most developing countries, the lack of GIS evaluation to improve implementation is a challenge for these organisations. The current GIS applications at SPTC, SWSC and SNHB were evaluated using maturity, value and GIS product assessments. Four methods of analysis were used for data analysis: GIS maturity calculation; relative frequency of maturity calculation; gap analysis; and GIS value assessment. The results found that the SPTC, SWSC and SNHB were all in the exploitation stage of maturity. The overall relative frequency of maturity in the dimensions is the following: 35% of indicators are in the exploration stage; 56% are in the exploitation stage; and 9% are in the enterprise stage. The gap analysis shows that the organisations are in the exploitation stage of maturity. Cost prevention, coordination, employee satisfaction, better data management, time saving and better quality of information were regarded as the main ways in which GIS add value to organisations. The GIS product assessment results show that the overall compliance rate with the cartographic standards is 57.09%.
The characterisation of borehole water properties and soil salinity across seasons for the period 2016-2020 with some links to rainfall and sugarcane yield in the Makhathini Irrigation Scheme, KwaZulu-Natal
(University of the Witwatersrand, Johannesburg, 2024) Ndwamato, Ramabulana Cassius; Scholes, Mary
The sugar business in South Africa has a strong socioeconomic development focus in rural regions, creating jobs, giving a source of revenue, and constructing transportation and communication networks. Despite its benefits, the sugar sector has faced several obstacles mostly by Small-Scale Growers (SSGs), which have led to a decline in sugarcane production. This study analysed borehole water properties such as electrical conductivity, water levels, and temperature at the Makhathini Irrigation Scheme in KwaZulu-Natal. The quality of water from the Jozini/Pongola Dam used for irrigation was also analysed, in addition to the salinity levels of the soil at the irrigation scheme. Water from nineteen (19) boreholes within the irrigation scheme between 2016 and 2020 was collected every three months from January and tested. Annual water quality data collected upstream (PR1) and downstream (PR2) of the dam were obtained from the Department of Water and Sanitation. One kilogram of soil was collected from six sampling points, respectively, within the Makhathini Irrigation Scheme and sent for testing at the Agricultural Research Council Institute of Soil Water and Climate. Rainfall data and annual sugarcane yield data were obtained and analysed. The ANOVA results showed a significant (p < 0.05) difference in electrical conductivity (EC) between all 19 boreholes in the five-year data. The Tukey test also confirmed the electrical conductivity’s significant (p < 0.05) variation across all boreholes during dry and wet seasons. The borehole water level analysis shows that no significant (p > 0.05) difference was observed in dry seasons, but there was a significant difference in the wet seasons. The Tukey test also confirmed that the borehole water levels varied significantly during the wet season for the five-year study period, suggesting that the water levels were shallow in the wet seasons compared to the dry season. The borehole water temperature analysis indicates no significant (p > 0.05) difference for all seasons from 2016 to 2020. The water collected at PR1 suggests that the water from the dam is of acceptable quality for irrigation, while the return flow to the Pongola River at sampling point PR2 had high SAR, EC, and PO4 - concentrations. Samples collected downstream (PR2) show signs of pollution. This suggests that water contamination occurs when water passes through the Makhathini Irrigation Scheme. A t-test analysis reveals that pH, NO3 - , and NO2 have no significant (p > 0.05) difference, but SAR, EC and PO4 - were significant (p < 0.05). The measured parameters were compared to the Department of Water Affairs and Forestry standards for the quality of water used in agricultural irrigation. The correlation analysis between rainfall, borehole electrical conductivity, borehole water levels, and sugarcane yields revealed that while rainfall influenced borehole electrical conductivity, water levels, and sugarcane yield, the effect was minimal, possibly due to irrigation volumes. Rainfall had a positive effect on sugarcane production and EC but a negative effect on water levels. Soil salinity analysis demonstrated an increase in the soil's electrical conductivity with each passing year. The ANOVA analyses for sugarcane yield and soil salinity reveal statistically significant differences (p < 0.05). The accumulation of salts in the soil at the Makhathini Irrigation Scheme, also seen by the contaminated return flow to the Pongola River, reduces sugarcane yields. Water properties of the sugarcane irrigation water affect the soil salinity in the irrigation scheme and, consequently, the decline in sugarcane production by small-scale growers.
The effects of elevated carbon dioxide concentrations on the physiological and biological characteristics of Portulacaria afra
(University of the Witwatersrand, Johannesburg, 2024) Basson, Domonique Courtney; Risenga, Ida
There is a concern that rising atmospheric carbon dioxide (CO₂) concentrations may affect the medicinal or nutritional profile of medicinal plants. Portulacaria afra (P. afra) is a medicinal plant used by traditional healers to treat various skin conditions. The aim of this study was to determine whether elevated CO2 concentrations will affect the physiological and medicinal properties of the leaves, stems, and roots of P. afra. This was achieved by measuring the physiological, phytochemical, antioxidant, and antimicrobial activity of the various plant parts, which were exposed to ambient (420 ppm) and elevated (600 ppm) CO₂ concentrations and comparing them to samples grown in greenhouse conditions. The plant samples were placed in a Conviron climate stimulator for three months. Three harvests were completed during thistime. The physiological properties measured include the weight of the various plant parts as well as the chlorophyll content within the leaves. The phytochemical profile of the plant was examined through a set of standard colour tests (qualitative analysis) and the determination of the total flavonoid content (quantitative analysis) in all three plant parts exposed to the various treatments. The antioxidant activity was determined by analysing the scavenging activity of the extracts against 1,1 diphenyl-2- picrylhydrazel (DPPH) and hydrogen peroxide (H2O2) with the use of a spectrophotometer. The antimicrobial activity determined the extracts’ ability to inhibit the growth of six microorganisms related to skin conditions. The results of this study revealed that there was a 65% and 39% increase in the weight of the leaves and roots, which were exposed to 600 ppm, respectively. A higher phytochemical presence was recorded in plants exposed to 600 ppm. There was a significant increase in flavonoid presence and flavonoid content in the methanolic and hot water plant samples that were exposed to elevated CO2.The leaves, stems, and roots of P. afra exhibit strong scavenging activity against DPPH and even more so towards H2O2. The strongest antioxidant activity was 13 exhibited by the methanolic leaf extracts which were exposed to 600 ppm, against H2O2 (0.2±0.7 mg/ml). The antimicrobial activity of all three plant parts was relatively constant between the different treatments. Despite the relatively weak antimicrobial activity of P. afra (MIC values > 1000 (µg/ml), a notable increase in the antimicrobial activity of the leaves against Cutibacterium. acnes were observed in samples exposed to 600 ppm of CO₂. Portulacaria afra is a medicinal plant that exhibits great resilience towards elevated atmospheric CO2 concentrations. The phytochemical and biological properties in this study displayed either no change or an increase in activity, which suggests that P. afra may continue to provide relief against certain ailments in the future despite rising atmospheric CO2 concentrations
The impact of fly ash on the growth rate of maize (Zea mays L.) and the potential for fly ash to be used commercially in agriculture
(University of the Witwatersrand, Johannesburg, 2022) Riba, Mpho Mahlatse; Scholes, Mary
South Africa’s coal-fired power plants (CFPPs) produce about 34.4 million tons of fly ash (FA) per annum, as a by-product of the coal combustion process, which is stockpiled adjacent to these CFPPs. This FA contains traces of heavy metals (HMs), as a result it is a potential environmental hazard. The purpose of this study was, therefore, to establish the effects of (‘FA’) on the growth of maize (Zea mays L.), as well as its potential commercial use in agriculture due to its nutrient content, instead of maintaining the status quo. Another aim of the study was also to determine the phytoextraction abilities of the HMs (Mn, Cr, Ba and Mo) from contaminated soils by the maize plants. The study was conducted by planting maize seeds in five soil substrates with 0 %, 20 %, 40 %, 55 % and 60 % FA treatment, on mass basis. The ANOVA indicated that there were significant differences when comparing most of the mean stem length, number of leaves, root length and the mean mass of total plant dry biomass, across all the FA treatments, after 122 days of growth. The mean stem lengths after 122 days of growth were 86.67  20.55 cm, 148.33  13.87 cm, 154.17  18.10 cm, 121.17  14.99 cm and 149.50  24.20 cm for maize plants grown in 0 % , 20 %, 40 %, 55 % and 60 % FA treatments, respectively. The mean number of leaves were 12  1.87, 16  2.34, 18  2.83, 12  1.87 and 14  1.79 across all treatments, respectively. The key finding was that the growth of these plants improved with the amount of FA in the soil, with the plants that were grown in the 40 % FA treatment yielding the best results. The same observation was made with the root length and the mean masses of total plant biomass (roots, stems and leaves). Another important finding was that the accumulation of the HMs (Mn and Cr) in the plants increased, across the FA treatments, while their concentrations in the soil decreased across the FA treatments. The accumulation of Ba and Mo in the plants also increased, across the FA treatments, while Ba remained slightly constant and Mo increased in the soil. This indicated that the maize plants can potentially remediate Mn and Cr contaminated soils, through phytoextration, but are retained in the root system.
The impacts of landfill management site A on grass, soil, and surface water: a preliminary study in KwaZulu-Natal, South Africa
(University of the Witwatersrand, Johannesburg, 2024) Ndobe, Florence Nonhlanhla; Schwaibold, Ute
Environmental pollution is a major global challenge, and the prime pollution source is anthropogenic activities, including industrial and waste management activities amongst others. Heavy metals are known pollutants released due to landfill operations and pose a problem in the terrestrial ecosystem, aquatic ecosystem, and human health through exposure. There are well-documented studies of heavy metal contamination and its impact on soil, groundwater, and surface water, and plants in general, yet the characteristics of contamination can be unique to each landfill site. This study aimed to investigate the potential impacts of toxic waste leachate from a landfill site in KwaZulu-Natal on the surrounding grasses, soil, and surface water. The methodology involved two broad approaches to data collection, a quantitative approach which entailed collecting grass, soil, and surface water samples near the landfill site to determine the levels of heavy metals (As, Cd, Cr, Cu, Pb, and Zn) and their potential impacts, and a qualitative approach which entailed interviews with nearby residents to investigate the community’s perception and awareness of health and environmental risks associated with living close to the landfill site. Three sampling sites downhill from the landfill site were sampled, namely the central stream site (adjacent to the leachate/storm water dam one, downstream site (storm water dam two), and control site-upstream (northbound), and heavy metals concentration varied significantly between sample types and sites. In almost all cases, the heavy metals exceeded WHO permissible limits. Contamination factor (Cf), pollution load index (PLI), and ecological risk index (Ri) were also calculated and based on these, in grass Cr, Cu, Pb, and Zn contributed to very high contamination in the central stream area, whereas downstream, Cd showed very high contamination, suggesting a very high ecological risk. In soil, contamination levels and risk were mostly moderate to low. In surface water, Pb contributed to high contamination while downstream water was mostly moderately contaminated. The most common challenge highlighted by community members during interviews were air pollution, water pollution, dust, and noise nuisance. For all communities, headaches are the most commonly reported, followed by asthmatic conditions and respiratoryrelated distress. The results indicated that people living 1-2km away from the landfill site were likely more exposed to health and environmental-related risk than people living 3-5km away from the potential polluting sources. iii In conclusion, high heavy metal contamination in soil, surface water, and grass suggests a likely leachate leakage and/or the dispersion of other related pollutants in the surrounding environment, which requires a further in-depth investigation to find the signature source of pollution.
The influence of environmental change on the provision of cultural ecosystem services in selected rural villages, Limpopo Province
(University of the Witwatersrand, Johannesburg, 2024) Mokono, Khomotso; Twine, Wayne
Rural communities in communal areas in South Africa are vulnerable to significant environmental change, due to their heavy dependence on the local environment. The influence of local environmental change on the provision of ecosystem services (ES) has been well studied, but less attention has been paid to cultural ecosystem services (CES than the other categories of ES (provisioning, regulating, and supporting)) in the literature. This study fills this gap by focussing on the influence of environmental change on CES in rural communities. The study documents local environmental changes perceived by local communities, how these were perceived to impact the provision of CES, and how these perceptions differ across socio-demographic factors. Data were collected using key informant interviews (20) and survey questionnaires interviews (n=100). Survey respondents were stratified by village, gender, age group, and farmer type. The key findings were that residents identified a great variety of CES provided by the natural environment, including resources important in ceremonies, and as significant places for culturally important practices. These also included ES that would usually be classed as provisioning (e.g., wild foods) and supporting (e.g., grazing for livestock) services that had particularly important cultural value in addition to contributing to livelihoods. Furthermore, the residents identified significant changes to climate, soil, plants, animals, and water bodies, which were driven by local and external drivers. The most important finding was that the perceived influences of environmental change on the provision of cultural ecosystem services were mostly the changes influenced by climate. The village in which the respondents resided had a greater influence on the perception of CES and environmental change than other socio-demographic factors. This study provides valuable information and insight about local communities’ perceptions of cultural ecosystem services, and how they might be affected by environmental change.
The reporting of the sustainability goals and the Sustainable Development Goals (SDGs) in the context of the private sector in South Africa
(University of the Witwatersrand, Johannesburg, 2022) Mosi, Tumelo
Sustainability challenges continue to mount and the fate of this planet lies in a precarious position. In response, the United Nations has introduced a global agreement known as the Sustainable Development Goals (SDGs). These are 17 goals underpinned by 169 targets for addressing social, economic and environmental issues on a global scale. The SDGs seek to do so by unlocking the potential that lies within the private sector and more. The aim of my research was to assess the sustainability goals disclosed by the top 25 Johannesburg Stock Exchange (JSE) listed companies against that of five other countries in 2017. Furthermore, I compared the environmental SDG disclosure of five companies from the metals and mining sector as well as the consumer products sector respectively, within the same period. The sample was selected from the original sample of the top 25 JSE listed companies. Comparisons were done by analysing sustainability/annual/integrated reports of the top 25 JSE listed companies. The results for the sample showed South Africa to be lagging behind the other countries with regards to disclosing sustainability goals in the corporate sustainability reporting for 2017. From 2017 to 2019, the number of reports addressing environmental SDGs from the selected sectors showed an increase. Furthermore, the study companies from the metal and mining sector performed better than those from the consumer products sector with regards to environmental SDG disclosure. However, the environmental SDG score of the study companies from the consumer products sector increased relatively more within the three years of assessment (2017-2019). Variation was also found between the study companies from the two sectors with regards to preference for specific environmental SDGs which included Responsible Consumption and Production (SDG 12), Climate Action (SDG 13), Life Below Water (SDG 14) and Life on Land (SDG 15). Moreover, the iii interviews conducted with the relevant participants revealed that SDG awareness has improved overtime, however internalisation of the SDGs remains the biggest challenge.
The reproductive system of Campuloclinium macrocephalum and its implications for biocontrol implementation
(University of the Witwatersrand, Johannesburg, 2022) Moodley, Saness; Glennon, Kelsey; Goodman-Cron, Glynis
Invasive species are a threat to biodiversity therefore it is imperative to determine the factors that facilitate the invasion potential of a species. Campuloclinium macrocephalum Less. (DC), the ‘pompom weed’, is an alien invasive species in South Africa and is currently threatening the persistence of the grassland, wetland, and savanna biomes. The species is also significantly contributing to a decline in plant diversity by outcompeting native vegetation in these areas. Various integrated approaches using combinations of chemical, mechanical and biocontrol management programs have been developed to manage the spread of the species in its invaded range, however the species has still been able to persist. The persistence of the species was hypothesised to be a consequence of the co-occurrence of apomixis and polyploidy, however despite the identification of triploid and tetraploid cytotypes in South African populations of the pompom weed, the reproductive strategy of the species has not yet been determined. The aim of this study was therefore to infer whether populations of C. macrocephalum (pompom weed) reproduces via vector-mediated crosses, self-pollination or apomixis (either facultative or obligate) and examine the relationship of the mode of reproduction with ploidy level. Male fertility was also assessed to ascertain if interploidy gene flow was possible. The collated information was then used to infer the potential impact of reproductive strategies and polyploidy on biocontrol. All examined populations were shown to have high mean pollen viability percentages of 90% and 98% with no significant differences in pollen viability amongst the four populations. The high pollen viability percentages were supported by prolific pollen grain germination on the stigmatic surfaces (margins of style at base of style branches) and the sides of the style. This suggested that the pollen grains can fertilize and interploidy mating is likely possible in South African populations of the pompom weed. It is plausible that the high pollen viability is enabling triploids to act as a ‘triploid bridge’. However, the high pollen viability was confounded by the pollen tube analyses revealing that pollen tube growth is being arrested on the stigmatic surface suggesting that overall male fertility is low. The arrested pollen tube growth is typically associated with a ‘triploid block’. Nevertheless, the production of viable gametes can reduce the triploid block and facilitate gene flow between populations. The predominant mode of reproduction was determined by assessing the contribution of insects to pollen transfer, pollinator exclusion experiments, germination trials, pollen tube growth to the ovules and genetic analyses. We found that the African Monarch butterfly (Danaus chrysippus) and the honeybee (Apis mellifera) contributed most to pollen transfer in comparison to the other insects visiting C. macrocephalum. A pollinator exclusion experiment showed that the pompom weed can set seed in the absence of pollinators, albeit at lower quantities than in the open treatments. Nevertheless, germination percentages showed that reproductive success was similar between open and bagged treatments in each population. The Modderfontein population showed lower reproductive success and seedling establishment in comparison to the other populations, presumably due to the severity of the biocontrol infestation on this population. Genetic analyses revealed low genetic variation within and amongst populations. Pollen tube analyses showed no pollen tube growth to the ovules in all samples, which suggests that seed set is independent of fertilization. The lack of pollen tube growth is a strong indicator of obligate autonomous apomixis which is further corroborated by the low genetic differentiation between maternal plants and their respective offspring. The co-occurrence of apomixis and polyploidy made it difficult to discern which factor contributes more to the invasiveness of the species, however, we hypothesise that autonomous apomixis provides the pompom weed with the competitive advantage to persist in its invaded range. However, further studies on the reproductive strategies of tetraploid cytotypes are needed to confirm this hypothesis. The low genetic variation suggests that all populations should be equally susceptible to biocontrol agents, however that this may be affected by other factors such as environmental conditions or phenotypic plasticity. Phenotype plasticity refers to a single genotype producing different phenotypes in response to environmental conditions. This could reduce the efficacy of biocontrol agents as they may exhibit differential responses on different phenotypes
Water quality assessment at Vaalkop Dam in North-West Province using multispectral remote sensing data
(University of the Witwatersrand, Johannesburg, 2022) Mthimkulu, Lindy Ndzumbululo; Adam, Elhadi
Water is a life-sustaining resource for all organisms. As much as nature share the value of water with human being it cannot supersede how human have become dependent on water for drinking, sanitation, farming, mining, and other industrial purposes such as power generation. Water is perceived as a vital component in the fight against poverty, the foundation of any successfully growing and developed country is also measured on water and sanitation provision (Basson et al., 1997). The water law in South Africa stresses that essential human and ecological necessities must be given (DWAF, 1998) and that the misuse of water from all perspectives should be feasible (New, 2002).

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