3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Phenological advance in the South African Namaqualand Daisy Bloom over the past decades(2024) Snyman, Pascal LudwigClimate change is driving changes in environmental suitability, competitive dynamics and phenological cycles of plants and animals. Through the analysis of the timing of phenological events the impact of climate change on plant and animal species can be measured and assessed effectively. In this study the impact of climate change on the timing of bloom of Namaqualand daisies is explored. Although the Namaqualand is described as a desolate and arid region during the summer months, the region is transformed into a wonderland of colours during the springtime flowering. Using documentary sources including newspaper archives from The Rand daily Mail, Volksblad and Die Burger as well as social media records from Flickr and iNaturalist, a phenological dataset spanning 1935-2018, including first flowering, full bloom and end of bloom dates for the Namaqualand daisies was compiled. First flowering and full bloom phenology of the Namaqualand daisies are advancing significantly at rates of 2.6d.decade-1 and 2.1d.decade-1. Climatic data, collectively spanning 1959-2018, from seven Namaqualand weather stations were individually correlated to the three flowering datasets. Calculations reveal that temperatures are increasing significantly in Namaqualand. The overall increase in temperature, from 1959-2018, for all seven assessed weather stations in Namaqualand is calculated at 1.18°C. Although no significant changes in precipitation were calculated, five out of the seven weather stations demonstrate slight decreases in precipitation over time ranging between 0.05-9.32mm from 1959-2018. The timing and amount of precipitation in the Namaqualand region is highly variable over time. For the periods spanned by both climate and phenology data, the relationships between the two were explored. Increasing temperatures are driving the calculated advances of the daisy flowering dates at statistically significant rates of change ranging from 0.01-0.11d.°C-1. The main climate drivers of Namaqualand daisy flowering phenology are winter and spring temperatures, the onset of the winter rainy season during April and May, and total winter precipitation. The rates of advance and climate drivers are broadly consistent with global phenological meta-analyses and records for the Southern Hemisphere. The advances in the timing of Namaqualand daisy flowering will have a significant impact on the tourism sector in the region, as flower viewing tours need to be prearranged months in advance.Item Habitat selection by a threatened lizard, the sungazer (Smaug giganteus): implications for conservation(2024) Stanton-Jones, WadeClimate change and habitat transformation are some of the primary threats that reptiles face as a consequence of persisting in their selected habitats. Some species, such as habitat specialists, may be particularly vulnerable to these threats given their restricted geographic ranges, strict habitat requirements, and limited dispersal abilities. Knowledge of the factors that drive habitat and microhabitat selection by a species, the impact that habitat transformation may have on that species, and how the species is expected to respond to climate change is necessary for informing conservation management strategies. Smaug giganteus (the sungazer) is a threatened (Vulnerable), habitat specialist lizard that is endemic to the Highveld grasslands of South Africa. Unfortunately, suitable habitat exists in a landscape where anthropogenic activities (e.g., agriculture and mining) are prevalent, and a major threat that sungazers face is habitat transformation and fragmentation. Sungazers are unique within their family (Cordylidae) in that they rely on self-constructed burrows in specific microhabitats within the grassland matrix as long-term, often permanent, shelter and refuge sites. Because of this, aspects of their life history, and the current threats that they face, sungazers may be particularly vulnerable to the combined effects of climate change and habitat transformation. The primary aim of this thesis was to assess the consequences of habitat selection and use by sungazers by investigating the potential impact of climate change on habitat suitability for the species, the fine-scale impacts of habitat transformation, and to identify the microhabitat requirements by sungazers such that recommendations for future conservation management of the species could be made. The potential impact of climate change on habitat suitability for sungazers was assessed by projecting their current ecological niche envelope into the future, under different climate change scenarios. The models predicted that sungazers may experience minor range contractions under the moderate case scenario, but vulnerability to climate change increased under the worst-case scenario. At the broadscale level, the models predicted that sungazers would shift their geographic range to the southwest. However, given the species life history traits, limited dispersal capacity, and the fragmented habitat in which subpopulations exist, climate tracking is unlikely, and sungazers may be more vulnerable to the effects of climate change than predicted by niche models. An assessment of the demographics and dynamics of four sungazer subpopulations existing at sites with different habitat conditions revealed that the impact of habitat transformation on sungazers may be more devasting than what was previously reported. In this study, the sungazer subpopulations existing in habitats transformed by mining activities, and severe overgrazing have declined by more than 50% over a 16-year period. This assessment at the subpopulation level (colony level) suggests that the current size of the sungazer population is probably an overestimate. A comparison between the microhabitat characteristics surrounding sungazer burrows and random sites in the landscape revealed that sungazers use microhabitats comprised of low vegetation cover and short grasses in which to construct their burrows. Burrow construction in these microhabitats generally occurs on northerly facing slopes. When constructing their burrows, sungazers tend to orientate burrow entrances in the same direction as the aspect of the slope but northerly directions are preferred. This thesis provides the first insights into the potential effects that climate change may have on sungazers in the future and highlights the severity of impact that habitat transformation has on sungazers at fine spatial scales. The findings not only justify the importance of conservation management for sungazers but provide critical information to assist with future conservation protocols.Item Exploring extreme rainfall events in KwaZulu-Natal over the period 1989-2019(2024) Ntleko, Thabisile Phiwengomusa ZibusisozonkeChanges in weather and climate extremes have been observed across the globe. These include an increase in the frequency, magnitude, and severity of extreme events, have been attributed mainly to climate change due to increased anthropogenic activity since pre-industrial times. Although these weather and extreme events have increased and intensified globally on average, some spatial and temporal variations of trends are evident at regional scales. This study was conducted to explore the incidence and trends of extreme rainfall events over KwaZulu-Natal for the period 1989-2019. Rainfall data was sourced from the South African Weather Service for 11 stations distributed across the province. Extreme climate events (ECEs) were identified by calculating subsets of the World Meteorological Organisation (WMO) Expert Team on Climate Change Detection Indices (ETCCDI) and WMO Expert on Sector-Specific Climate Indices (ET-SCI) for each of the 30 years of interest. Thereafter, trends in these extreme climate events were calculated using linear regression. The results reveal marked spatial and temporal differences in both the occurrence of the ECEs and their trends. The incidence of ECEs depict a seasonal pattern, where majority of events occur during the summer rainfall months. However, over the coastal regions ECE’s occur throughout the year and exhibit more frequent and intense events compared to overland regions. The trend analysis detected a majority of decreasing trends in the frequency, intensity and duration of extreme rainfall events for the period of study, with only 10 of the 77 calculated trends being statistically significant. The spatial distribution of trends was heterogeneous for most parts of the province apart for the KwaZulu-Natal Midlands, which consistently observed decreasing trends for all calculated indices.Item Perspectives on climate change and energy security in South Africa: a study of Eskom(2024) Rasimphi, Khuliso JamesGlobal changes in climatic conditions have both direct and indirect implications on various energy sources and systems, particularly in terms of energy generation vis-à-vis security for sustainable social-economic development. This study examined the relationship between climate change and energy security in South Africa, focusing on energy production, accessibility, and affordability as key determinants. The investigation also explored measures to minimise Eskom’s carbon footprint and opportunities for transitioning the energy sector to cleaner energy sources. A mixed research method, including structured questionnaire surveys, semi-structured interviews, observations, and existing records, was used for data collection. The data was mainly analysed by use of the Microsoft Excel package to generate statistical correlations and relationships to draw the key conclusions contained in this paper. Eskom coal power plants’ ten-year (2010 to 2020) carbon footprint was found to be constantly above 200 million per year. The power utility’s ten-year CO2e trend was primarily influenced by production activities. This is because all Eskom’s coal power plants (except for Medupi) do not have CO2e abatement technology, and the available technologies in the market are too expensive. The study also found that Waterberg (LP) and Nkangala (MP) regions, where most coal power plants are located, have been receiving inconsistent and insufficient rainfall from 2010 to 2021; and projections are suggesting a further decline in precipitation distribution and incline in average temperatures in these regions. Despite all these glaring climate change implications, the current study found that water consumption (2020 to 2021 trend) at coal power plants remained high even in periods wherein energy availability factor had dropped, and therefore indicative of thermal inefficiency. The study also found that South Africa’s slow approach in building a climate change resilient and adaptive energy system was caused by a slow and ineffective implementation of IRP. Thus, South Africa must embark on a decisive transition programme to cleaner energy sources mix as a critical and urgent measure to decarbonize and enhance the energy sector’s resilience against climate change effects, and ensure energy availability, reliability and affordability. The study concludes that Eskom coal power plants should focus their efforts on resolving maintenance problems, operational inefficiencies, and developing adaptation strategies to decarbonize and build resilience against climate change vulnerabilities such as irregular precipitation and high temperature, while ensuring energy security. The energy policy and IRP should be adaptive and continuously informed by regional research to determine the most suitable energy sources for specific regions to ensure an effective transition to cleaner energy systems.Item The nature of climate change communication in South Africa: its past, political and socio-economic undertones(2024) Sithole, EnochThe United Nation’s Intergovernmental Panel on Climate Change (IPCC) has noted that the observed and projected impacts and risks generated by climate hazards, exposure and vulnerability have increased with impacts attributable to climate change. The increase in climate extremes has led to some irreversible impacts as natural and human systems are pushed beyond their ability to adapt. Climate change has altered terrestrial, freshwater and ocean ecosystems at a global scale, with multiple impacts observable at regional and local scales, where changes in the ecosystem structure, species, geographic ranges, and timing of seasonal life cycles is apparent. Climate change is having diverse and adverse impacts on human systems throughout the world, affecting water security, food production, health, livelihoods, settlements, and infrastructure. According to the IPCC, it is “unequivocal” that human influence is warming the atmosphere, land, and oceans. The world climate body adds that humans are exacerbating climate change through the burning of fossil fuels and other activities. Faced with the global warming challenge, humanity has no choice but to engage in measures to mitigate and adapt to the resulting climate change. Climate change communication has been identified as one of the measures that will need to be applied in addressing climate change. This is so because for action against climate change to succeed, society will need to be mobilised to change behaviour and implement other measures. Climate change communication is the awareness, education, and mobilisation tool thereof. This PhD thesis investigates climate change communication in South Africa over the past century (since 1902) through an analysis of climate change-related news articles in three newspapers – the Rand Daily Mail, Mail & Guardian, and Business Day. The idea is to establish how key stakeholders – the government, the business sector, the scientific community, non-governmental organisations (NGOs) and the media – have communicated on climate change, and whether their communication on the subject has been underpinned by political and socio-economic considerations. Results show that while the scientific community has been communicating on ‘climate change’ from about 1935, when the first article on the subject was published by the Rand Daily Mail, other stakeholders such as the government, the business sector, and NGOs, only started communicating on climate change in the 1990s. Government and business sector communication has been underpinned by financial and economic undertones. Climate change communication scholarship in South Africa has been limited v compared to that elsewhere globally, especially in western countries. This thesis argues that South Africa will need to massively improve its climate change communication, as such communication plays a fundamental role to ensure a seamless transition from coal and other fossil fuels to a low carbon economy.