Browsing by Subject "Environmental and Geographical Sciences"

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    Open Access
    An analysis of nature-based treatment processes for cleaning contaminated surface water runoff from an informal settlement: a case study of the Stiebeuel River catchment, Franschhoek, South Africa
    (2022) Nicklin, Emily; Winter, Kevin
    Contaminated surface water runoff from inadequate drainage and sanitation systems in informal settlements threaten the quality of available freshwater and can negatively impact both human and environmental health. Biofiltration systems (biofilters) provide water pollution controls without inputs of additional energy and chemicals, placing them in the overall context of the need for affordable and sustainable stormwater infrastructure in informal settlements. In addition, cleaned waters from biofilters may be suitable for some reuse applications if they are well-designed and maintained. However, most research is conducted in developed countries where heavy metals are the main surface water pollutant. Consequently, little is known about the extent to which biofilters can be used to meet the water quality targets in conditions likely to be found in informal settlements. In addition, no attempts have been made to recover or reuse the surface water runoff from informal settlements, despite its high nutrient loadings. This study analyses the extent to which biofilters can be used to clean and reuse contaminated surface water runoff from informal settlements. The objectives are threefold: (i) to analyse the performance of two field-scale biofiltration cells (one vegetated and one non-vegetated) that are batch-fed with surface water runoff from an upstream informal settlement; (ii) to determine the effects of varying operating, design and environmental parameters on the performance of the cells; and (iii) to develop a model which predicts the outflow pollutant concentrations under varying conditions. Both cells effectively reduced ammonia (NH3), Total Phosphate (TP) and Escherichia coli (E. coli) concentrations, but leached nitrate (NO3 - ) and nitrite (NO2 - ). The treated waters were suitable for irrigational reuse, however, additional disinfection was required to reduce faecal contamination in some cases. Correlation analyses showed that inflow water quality significantly influenced cell performance, with the vegetated cell outperforming the non-vegetated cell under higher inflow pollutant concentrations. Multiple regression models also investigated several parameters influencing outflow NH3 and showed that inflow pH, temperature and NH3 concentration can be used to determine the outflow NH3 concentration of the cells. These models are important for predicting cell performance and thus can be used to improve the design and/or operation of the cells for varying inflow water quality conditions.
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    Open Access
    An analysis of the perceptions surrounding the re-zoning of the Tsitsikamma Marine Protected Area
    (2019) Muhl, Ella-Kari; Sowman, Merle; Mbatha, Philile
    Marine Protected Areas (MPAs) are an increasingly important tool for sustainable marine governance. However, their effectiveness is improved if designed to consider how people value and interact with coasts and marine resources designated for protection. This research critically examines the different perceptions of stakeholders towards the rezoning of Africa’s oldest MPA, the Tsitsikamma National Park (TNP) MPA. In South Africa, MPAs created prior to 1994 under the Apartheid regime disregarded local communities’ rights to the coast and in some cases removed or restricted access, with no consultation. In December 2016 the TNP MPA was rezoned from a 'no-take’ MPA to a partially open protected area with the aim of readdressing historical exclusion and to provide managed access and benefits to adjacent communities. This thesis explores the perceptions of different stakeholders to the rezoning process and the underlying values, worldviews and beliefs that influence these perceptions. The research also examines the nature of participation in the rezoning process, including issues of representation, trust and legitimacy. Data collection is based primarily on 55 semi structured key informant interviews from the nine different communities adjacent to the Tsitsikamma MPA, scientists, NGO and government officials, as well as a focus group with eight representatives from South African National Parks. Data sources are supplemented with census and mapping information, field observations and a participatory film project. Findings from this research identified and examined the diverse perceptions of stakeholders about the re-zoning and highlighted how different groups have very different perceptions about the benefits of the rezoning for either marine conservation objectives or community economic, livelihood and wellbeing aspirations. What emerged clearly was that perceptions are influenced by values, worldviews and beliefs and that failure to recognize and incorporate these perceptions in planning, discussions and decision-making leads to ongoing contestation and conflict. The research thus highlights the challenge of balancing community rights and needs with conservation goals in a rapidly changing marine context, and highlights that understanding different perceptions and values that underlie these perceptions and providing the space to allow these different views to be shared is important for collaborative governance of MPAs in South Africa. Based on an enhanced understanding of perceptions, recommendations are made regarding the importance of recognizing and incorporating perceptions in planning and decision-making and promoting greater participation in governance.
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    Open Access
    Analysing the relationship between seed security and food security: the case of Chimanimani district, Zimbabwe
    (2021) Ncube, Bulisani Lloyd; Wynberg, Rachel; McGuire, Shawn
    Many smallholder farmers in southern Africa rely on crop production as their main livelihood source. However, they often suffer from a lack of appropriate seed as well as high levels of food insecurity. Interventions such as community seed production, seed aid, and input subsidies are used to address these concerns. However, the relationship between seed security and food security has been understudied. This study thus aimed to explore the factors that have an impact on the relationship between seed security and food security. This was done to enhance understanding about the conceptual linkages between the dimensions of seed security, which include availability, access, and utilisation, and those of household-level food security, which include dietary diversity and food consumption. The case study was conducted across two sites in Chimanimani district of Zimbabwe. Methods included both quantitative and qualitative research methodologies. Quantitative data were subjected to statistical analyses while qualitative data were analysed for themes and trends. Results showed the dominant role of informal seed systems in ensuring improved access to affordable and timely seed to smallholder farmers. Informal seed sources were more reliable than formal sources in ensuring that seed was available on time and in closer proximity to households. Seeds sourced informally also showed comparable quality to that from formal sources. The relationship between seed security and food security was shown to be complex and contextual rather than direct or one-directional. Seed security does not necessarily equate to food security, nor does seed insecurity necessarily lead to food insecurity. Although timeliness and proximity of seed affect its availability, these did not directly relate to access to food. Similarly, household assets and income correlated with better food security status, but did not always ensure access to seed. This is because farmers' seed sources were predicated on non-financial factors such as social relations. The quality of farmers' seed was essential in ensuring that adequate food was produced. The thesis argues that the combined factors of seed availability, access and utilisation are essential in ensuring better crop productivity and improved food access. Findings underscore the manner in which household determinants such as assets, farming practices and geographical characteristics, as well as broader contextual factors, affect and influence the relationship between seed and food security. These results imply that interventions such as community seed production, seed aid, and input subsidies do not automatically result in improved seed security and therefore food security. Efforts to enhance seed and food security should be informed by specific household characteristics that take account of wider contextual factors such as climate, as well as socioeconomic and political processes that have a historical influence as well as a continuously evolving effect on farmers' seed and food security.
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    Open Access
    Are all wetland models the same? Comparing wetland models and streamflow regulation of catchment-scale hydrological modelling tools under a changing climate
    (2023) Metho, Penisoh; Wolski, Piotr
    Comparing how wetlands are simulated in different hydrological modelling tools is needed to identify their suitability in different contexts. A simulated wetland will result in predictions of streamflow regulation, e.g., storing flood water and reducing high flows and releasing water in drier periods, which may or may not be realistic for a given area. Evaluating wetland models is critical for navigating the different types of physical wetlands with variable influences on streamflow, and the different simulated wetlands conceived in the plethora of modelling tools (i.e. software) available for use. A recent study found that sometimes wetlands are excluded from hydrological models used to inform water resource decisions. When wetlands are included in a hydrological model, few studies identify process similarities between the actual and modelled wetland or the realism of the modelled impacts of the wetland on streamflow before applying the model's output to water resource decisions. This research aims to identify and evaluate wetland characteristics, processes and impacts on catchment streamflow in different modelling tools and models (i.e. setups in a tool). Evaluating wetland models supports wetland-inclusive modelling and ensures that a wetland model is hydrologically sound and suitable. An unchannelled valley-bottom wetland located in the upper Kromme catchment, Eastern Cape, South Africa, was used. Wetland models were compared as independent units conceptually and as functional units within the catchment by modelling. First, using qualitative analysis, a conceptual assessment of wetland model structures in ACRU, WRSM-Pitman, MIKE SHE coupled with Hydro River and SWAT were considered in the context of the case study wetland. Second, using quantitative analysis, model outputs from wetland models in ACRU and WRSM-Pitman were assessed for model performance, behaviour and streamflow regulation during droughts and floods. The predicted impact of the wetland on catchment hydrology was determined from scenarios with and without a wetland and modelled wetland storage fluxes over the whole simulation period, four severe floods and three drought periods. The results from the qualitative and quantitative comparisons suggest that similarities between the physical and simulated wetland improves the likelihood of model suitability, good model performance and streamflow regulation predictions. Additionally, models setup for the same wetland with the same input data simulated potentially acceptable but different streamflow totals: for an observed total of 9.13 Mm3 ; WRSM-Pitman's comprehensive wetland simulated 10.64 Mm3 ; and from ACRU's riparian zone and wetland HRU's simulated 11.31 Mm3 and 8.89 Mm3 , respectively. Modelled actual evapotranspiration was underestimated by the riparian zone wetland (946.08 mm), overestimated in the comprehensive wetland model (2 054.80 mm) and moderately similar in the wetland HRU when compared with remotely-sensed data (1 520.30 mm). During extreme events, all models simulated flood attenuation while drought responses were variable (two wetland models predicted streamflow attenuation). By implication, the results suggest that good model performance does not guarantee the simulation of expected streamflow regulation roles recorded in literature. Furthermore, variable water yields and wetland impacts from the models demonstrated the possibility for different modelling efforts to result in different water supply, use and conservation measures. The study highlights the importance of contextualising model output for catchments with wetlands before applying the simulations to impact assessments or future climate scenarios.
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    Environmental change and soil organic carbon storage in a dust emission hotspot, Free State, South Africa
    (2023) Ndara, Nolusindiso; Eckardt, Frank; Palmer, A
    Drylands farming areas are subject to land cover or land use change, climate change, and a variety of land management practices which may contribute to dust emissions and soil loss, a common symptom of land degradation. The goal of this study was to establish how the shift in land cover or land use change affects the occurrence of dust and determine the climate constraints and mitigations to crop production with focus on the dustiest parts of South Africa in the Free State Moreover, the study wished to establish land management strategies suitable for enhancing the storage of soil organic carbon and associated ecosystem services. To investigate how the shift in land cover or land use affects the occurrence of dust from 2006- 2016, the study firstly identified the spatial and temporal changes of land cover (LC) using the 2000 and 2013-2014 land cover maps derived from Agricultural Research Council. The results showed that grassland is still dominating in 2013-2014 but has decreased by 22 % from 2000. Cultivated land on the other hand has increased by 26 % from 2000 to 2013-2014. Some of the changes seen in recent data might also be the result of the associated data products. The change is however continuous and significant as major LC changes occurred over long-time scales. Cultivated land and grassland are dominant land cover and cultivated land is substantially being used to meet the economic demand (international maize price). Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index (MODIS EVI) was used to assess vegetation cover for the site of the start of dust. MODIS EVI indicated that vegetation plays a significant role during the occurrence of atmospheric dust. Sparse vegetation (EVI ranging from 0 – 0.18) is directly proportional to dust production. Dust events were generally observed in cultivated land especially in 2015 and 2016. Moreover, findings showed that vegetation is not solely a factor that affects dust production; rainfall, temperature and wind speed also contribute. Crop and land cover data obtained from Department of Agriculture, Forestry and Fisheries (DAFF) identified the dominating crop and land cover around each dust source as fallow land, maize fields, and pasture. For instance, dust source August 29th 2006 had 11533 ha of fallow land and 10795 ha of maize, and dust source September 15th 2016 had 7737 ha of fallow land and 4599 ha of pasture which suggest that dust does not exclusively depend on the amount of vegetation but also on the type of vegetation. To achieve the second aim, the study used data from Climate Hazard Infrared Precipitation with Stations (CHIRPS), Agricultural Research Council (ARC) and Standardised Precipitation 2 Evapotranspiration Index (SPEI) to determine the variation of rainfall in Free State. SPEI data showed that drought is becoming prominent and severe in Free State (2005, 2012, 2014 and 2016). ARC data showed a slight increase (357-408 mm/year) from two stations and a slight decrease from the other two stations in rainfall from 2005- 2016 and CHIRPS data showed a slight decrease (458-404 mm/year) from all the stations during the same period. Both CHIRPS and ARC data showed that there is a seasonal shift on the onset of rainfall; rainfall has shifted to late summer by approximately 62 days on average from 1981-2019 in Free State. Rainfall in Free State is becoming late (e.g., in 2011 rainfall adequate to make the soil moist was received in November) and number of rain events are decreasing (e.g., September 1981-2019 had 7 rainfall events greater or equal to 15 mm/day, 19 events in October, 52 events in November and 33 in December in Bultfontein weather station). This study used temperature data from ARC weather stations to determine how temperature and frost variation affect crop production in Free State. Findings indicated that temperatures have increased by ~ 1- 2 ○C in Free State and frost has decreased, and its onset has shifted by ~ 11 days. Frost occurred in Julian day of the year (DOY) 144 in 2005 and in 2016 there was no frost for the whole year in Bultfontein. The onset of frost is shifting to May and resulting to frost period decreased over the years. Decrease in frost is an advantage for crops that are planted in late summer, however increased temperatures are likely to result in crop failure, especially if rainfall is also low. Furthermore, the relationship between wind speed and dust occurrence was determined using the ARC and ERA5 datasets. The results showed that some years were characterised by high winds and some by low winds but generally there is no constant trend. The ARC maximum wind speed was 10 - 15 m/s and ERA5 maximum wind speed was 10 m/s. Both datasets showed that high wind speed occurs from August- November and many dust events are observed in these months. Additionally, high winds are mostly observed to occur on surfaces with sparse vegetation and in the absence of wind breaks which further promotes an increase in dust. Thus, it is important for farmers to leave crop residues after harvesting and practice moderate grazing. To achieve the third aim, the study further established land management strategies suitable for enhancing the storage of soil organic carbon. Soils sampled in 2019 from different sites in Free State were used to determine the amount of carbon and nitrogen. It is apparent that grassland can store more carbon especially in the Lixisols which appeared to have stored an average carbon of 1.23 g and maximum of 1.86 g from 0-2 cm to 20-30 cm depths. Moreover, cultivated land can store less carbon especially in the Arenosols which stored an average of 0.18 g and 3 maximum of 0.22 g from 0-2 cm to 30-45 cm depths. Findings suggest that grassland can store more carbon than cultivated land due to minimal disturbance of the land when compared to cultivated sites. Moreover, the study demonstrated that soil texture and grain size distribution play an additional role in carbon storage with higher loads linked to higher silt content (Lixisols) and less carbon being stored in soils with high sand content (Arenosols). More carbon was observed to be stored in soils with moderate sand content (Lixisols = 40 % of sand) and high silt content (54 %) and less carbon was stored in soils with high sand content (Arenosols = 80 % of sand) and moderate silt content (18 %). More carbon was shown to be stored in the top layers of the soil 5-10 cm and was observed to decrease with increasing depth. DAYCENT carbon model was further used to simulate soil carbon in different land management scenarios to come up with suitable land management options for storing more carbon in future. Results illustrated that native grassland can substantially store more carbon than cultivated land, however moderate grazing should be applied. This would allow for a reduction of future dust emissions and increase ecosystem services in the cultivated lands of the Free State. Overall, the study demonstrated that combining the investigation of LCLU, climate change and land management was important to better understand land degradation and identified possible mitigation measures.
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    Open Access
    Exploring the potential contribution of Environmental Impact Assessments for water resilience: a case study of in-situ upgrading of the Monwabisi Park informal settlement, Cape Town, South Africa
    (2022) Bieding, Natasha; Patel, Zarina; Simpson, Nicholas Philip
    Internationally, water resource management is complicated by a myriad of factors. Climate change is just one of such factors that has globally complicated water resource management due to erratic weather patterns, including extreme and prolonged drought. However, there also exist other factors such as rapid urbanisation, migration and inadequate infrastructure which have contributed towards water resource management being complicated. Water resource management therefore spans a wide scope ranging from managing the direct impacts of climate change on water availability to ensuring that water remains accessible to all. From a national perspective, water access is particularly a topical issue in South Africa, due to its ever-expanding cities and informal settlements. Cape Town is no different and in the same way, water access is directly affected by a myriad of factors including natural and social. Natural factors include drought, while social factors include rapid urban expansion, wastage and increasing demand by competing user groups. However, for informal settlements where limited access to water and inadequate socio-economic living conditions are the norm, water access remains a problem. The pre-existing conditions in this regard heightens informal settlements' challenge for access to water. Learning from the severe drought of 2015 to 2018 one of the impacts of climate change in the context of this research, the City of Cape Town introduced long-term policy interventions to ensure water access and promote water resilience by developing both the Cape Town Resilience Strategy and Water Strategy. Despite this progress at a strategic level, guidance on tools for environmental governance of project and local level water resilience remains lacking. This research uses a case study approach to explore Environmental Impact Assessments' potential contribution for water resilience in informal settlements. Water resilience in the context of this research implies that actions are implemented so that water remains accessible for informal settlements while its more vulnerable residents are empowered, in spite of the threat and impacts of future drought scenarios. The Environmental Impact Assessment is therefore explored as a ‘vehicle' or means through which such actions could be implemented and in so doing, contribute towards water resilience in the real world context. An Environmental Impact Assessment application of the in-situ upgrade of the Monwabisi Park Informal Settlement in Cape Town, South Africa, is analysed based on three themes of how contributions towards water resilience relevant to informal urban settings could be implemented, namely: (1) addressing the relationship between the ecological and social elements of the environment, (2) engaging with aspects of future threats of drought and the need to plan ahead and (3) supporting the Cape Town Resilience Strategy and Water Strategy with implementation to further achieve water resilience. The shortcomings of the case study revealed that the Environmental Impact Assessment addressed pragmatic issues relating to the decision-making attributes of the tool rather than substantive water resilience matters. Social and ecological elements were not treated as one system and planning ahead failed to incorporate relevant water resilience imperatives, even though the opportunities to do so exists through need and desirability criteria, which requires the tool to use forward planning policy and frameworks to inform development projects. Despite these two shortcomings, EIAs hold potential to align with and strengthen environmental governance plans, policies or programmes. This was found to be possible through mandated procedures and normative outcomes such as public participation, environmental education and community involvement, conserving and diversifying sources of water and environmental monitoring. These synergies between Environmental Impact Assessment and the Cape Town Resilience Strategy and Water Strategy provide entry points for Environmental Impact Assessments to contribute towards water resilience. However, the potential contribution of Environmental Impact Assessments to water resilience in informal settlements remains highly contingent on addressing systemic vulnerabilities exhibited in the social-ecological context and adequate preparation for future shocks and stressors.
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    Influences of customary and statutory governance on sustainable use and livelihoods: The case of baobab, Chimanimani District, Zimbabwe
    (2018) Kozanayi, Witness; Wynberg, Rachel P; Matose, Frank
    Scholars have engaged actively with the link between customary practices and ecological conservation in Africa as part of a broader debate on governance approaches for natural resource management. To a large extent, this is in response to a growing voice articulating the need to integrate traditional institutions and customary practices into a more contemporary form of governance for Africa’s democratic and socio-economic transformation. To date, however, the integration of customary and statutory approaches to governance has yielded only modest progress in the forest sector and knowledge remains limited about the interface between these governance systems and the effect of this dualism on natural resource management. Using the lens of the baobab tree, this research set out to address these gaps and to elucidate understanding of the interplay between customary and statutory governance in managing natural resources; the influence of such interactions on ecological sustainability and livelihoods; and the contextual factors that shape such approaches. Uses of the baobab tree as well as factors affecting access were analysed. Two study sites were selected on the basis of similarities in resource endowment and contrasting use patterns and forms of governance. Both quantitative and qualitative methods were used. Quantitative methods included an ecological survey to examine the relationship between different indicators of ecological sustainability and different tenure regimes. A household survey was also carried out to examine the extent to which households use and benefit from baobab products. Qualitative methods included focus group discussions, institutional mapping, ranking and scoring, and oral histories. The study engaged with debates around governance, bricolage, non-timber forest products, bifurcation, livelihoods and access. Findings show that the baobab tree is used in multiple ways by households, and has both consumptive values as well as intrinsic values which are typically overlooked in the discourse of natural resource governance. The study illustrates that the interest of traditional institutions in regulating baobab use and access has been informed by reasons relating to sustainable livelihoods, ecological sustainability and the need to maintain a delicate link between environmental sustainability, the spirits of the land and resource users. Local arrangements are robust, dynamic and are entrenched in the day to day lives of the resource users. These arrangements may not fit into existing technical toolkits or environmental blueprints, and policy from the top may not be connecting with reality on the ground. Although traditional authorities and customary practices have remained relevant for local people in the realm of resource governance, they are weakening in the face of commercial baobab use. Where statutory forms of governance are overlaid onto existing customary forms of governance without due regard for local practices, unintended consequences arise. A key finding is that history profoundly informs the way local people harvest and use resources due to the long trajectory of the interplay between customary and statutory forms of governance that spans back to the colonial era. The main conclusion from the study is that both customary and statutory systems of governance are important, but need to be used in a graduated manner. Statutory forms of governance can be introduced to assist customary practices on a demand-driven basis. Results emphasise the importance of considering seemingly peripheral forms of governance such as customary practices within the continuum of resource governance in rural areas.
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    Investigating the habitat selection and dietary preferences of a largely sedentary population of blue wildebeest in the Kgalagadi Transfrontier Park – impacts of permanent surface water provision in a semi-arid environment
    (2018) Weeber, Joshua; February, Edmund; Hempson, Gareth
    The continued provision of waterholes since the early 1930s has facilitated the formation of a largely sedentary population of blue wildebeest (Connochaetes taurinus) in the Kgalagadi Transfrontier Park. However, other environmental variables may influence the distribution of this resident herd within the riverbeds of the Park. I explore the effects of water quality, forage abundance, tree density and river width on wildebeest habitat selection. I do this through a combination of an analysis of two years of wildebeest census data, published water quality data and a series of transects across the Auob and Nossob rivers for dung and grass sampling in the Park. My results show that water quality is a key predictor of wildebeest distribution, with animals strongly selecting for areas with access to fresh water over areas with saline or no water. Shade also emerged as a strong predictor of wildebeest distribution, demonstrating the importance of thermoregulatory behavioural adaptations in this arid savannah system. Wildebeest avoided areas of the riverbed that were densely vegetated, instead showing a preference for wider, open areas. This preference is likely a combination of two factors; enhanced predator detectability in open regions of the riverbed and the larger area of short grass communities present in this habitat. In this arid environment the distribution of available graze has long been considered an important variable in determining the distribution of wildebeest. I further examine my results showing that forage availability and quality plays a key role in wildebeest habitat selection through a stable carbon and nitrogen isotope analysis of wildebeest dung and the leaves of common shrubs and grasses to explore the spatial and temporal variation in wildebeest diet. These results show that wildebeest in my study site consumed a higher proportion of C3 plants than previously recorded in other areas of their range. This C3 intake increases in the dry season and in marginal, low use areas of the Park, suggesting that C3 plants are an important alternative food source to wildebeest during drought periods. This increase in C3 plants allow the animals to maintain their crude protein requirements throughout the dry season, despite a pronounced drop in the quality of available graze during this period. These results suggest that wildebeest were not food limited during the study period, although the distribution of these animals appears to largely reflect bottom up (resource based) mechanisms. A portion of the resident herd displayed some level of local movement, dispersing out of the riverbeds during the wet season before concentrating again near good quality waterholes in the dry season. This movement is likely driven by increased wet season forage outside the riverbed habitat and facilitated by ephemeral pools of water that form in pans in the rainy season. Grass species counts and grazing evidence were used to investigate the grazing habits of all herbivores in the riverbeds of the KTP. My results suggest that herbivores are more restricted in their grazing choices during the dry season. While there was no conclusive evidence to suggest that this was a direct result of grass quality, it is likely that the pronounced decrease in grass quality during the drier months does play a role in herbivore grazing habits.
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    Palaeoenvironmental reconstruction in South Africa's year-round rainfall zone using multiproxy geochemical analyses on lake sediments from Swartvlei
    (2019) Maboya, Matjie Lillian; Meadows, Michael; Haberzettl, Torsten
    Coastal lakes in the south coast of South Africa contain sediments with good records of palaeoenvironmental changes. Swartvlei is the largest of the lakes in the Wilderness Embayment and is connected to the Indian Ocean via an estuary. The lake is believed to have been formed during sea-level regressions in the quaternary, and separated from Groenvlei lake between 4000 and 2000 cal BP. There are questions about dominant precipitation regimes as well as the onset, cessation and altitude of marine transgressions in the area. In this study, Holocene sediments from Swartvlei Lake were extracted and investigated using multiple methods. These include organic and inorganic geochemical proxies and multidating approach through radiocarbon and OSL dating. A composite profile was made using marker layers with lithostratigraphic distinctions combining three cores into one continuous, 7 m long core spanning 8600 cal BP. The core was subdivided into two distinct zones namely, Unit A (8600 to 3500 cal BP) and Unit B (3500 cal BP to present), identified using cluster analysis on particle size data. The results reveal low sea-levels with limited precipitation and aquatic productivity during the early Holocene, followed by a marine incursion from 4500 to 3500 cal BP and moister conditions thereafter. This marine incursion, marked by increased Ca and TIC concentrations, occurred when the physical barriers were breached, and the estuarine channel widened due to a landward strandline migration. Pronounced riverine input due to increased precipitation was observed after 3500 cal BP, with strong minerogenic input and lowered sealevel. An influx of silt and clay material that dominate the top half of the core marks Swartvlei’s evolution into more lacustrine conditions and its separation from Groenvlei during the same period. A more humid climate is further inferred from organic proxies that indicate a greater in-wash of vascular vegetation during this period, as well as higher productivity from 3500 to 1400 cal BP. In addition, high biogenic silica concentrations indicate increased bio-productivity during the Little Ice Age (LIA) while increased sedimentation rates suggest that anthropogenic activity impacted the lake from 150 cal BP. This study adds insight to the geomorphic evolution of Swartvlei and highlights the usefulness of geochemical analyses in the elucidation of regional quaternary environmental and climatic changes.
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    Participative water demand management as an adaptive response within complex socio-institutional systems: a case study of Cape Town, South Africa
    (2019) Viljoen, Nina Susara; Winter, Kevin
    Worldwide adaptive strategies are being developed to address water insecurity. The current path of water resource management is not sustainable in the long-term, which requires the investigation of improved and adapted strategies. However, adaptation theory is proving difficult to implement. A range of serious practical issues are emerging as adaptation moves from theory to implementation. One of these is that the implementation of water demand management strategies are not aligned with the needs of the water users. Improvement can effectively enhance the success of water demand management, especially in cases where a water institution’s focus differs from the priorities identified by the water users. The aim of this thesis is to examine and analyse the role of participative water demand management in complex socio-institutional systems theory, and its potential to ameliorate adaptive capacity within the system in response to increasing water stresses. The research methodology consists of a literature review as well as a case study. The literature review include a discussion on the key concepts of adaptation theory, participative water demand management, and complex socio-institutional systems theory, amongst others. The case study contributed towards a practical understanding of the main aim of this thesis. The case study was undertaken in the City of Cape Town (CCT), which is a large metropolitan municipality in South Africa, a developing country. The theory suggested that individual behaviours can impact on water demands, especially during periods of drought, and that communication, participation and feedback among the social and institutional components must therefore form part of the adaptive strategies within water demand management. The literature alluded to a complex systems approach to water demand management, which can assist the different socio-institutional actors to increase their understanding of complex interactions and their capacity to adapt to these. A main empirical finding of the thesis is that adaptive measures, such as participation, is of paramount importance to the long-term sustainability of water demand management within the CCT, but are mostly lacking within its current management system. The results indicated that participative water demand management, as part of a suit of adaptive strategies, is able to increase flexibility within the CCT to address droughts more efficiently. Although water demand management in itself is an adaptive strategy to manage constraints on water resources, there is still a gap in finding better and more effective implementation methods to improve its acceptance by society and its success rates at reducing water demand. This thesis contributed towards new theoretical knowledge about adaptive theory, complex systems theory and participative water demand management as an adaptive response. It generated new thinking that contributes to improved and sustainable implementation of water demand management strategies within a developmental agenda that knows no bounds.
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    Reimagining Cape Town Walls: The Culture and Image of the City
    (2019) Warries, Rosca; Sitas, Rike
    Public culture creates an image of the city for both local and international publics to engage and encounter. The needs of the city to be globally recognised and create opportunities for economic growth can reveal discrepancies in development agendas and raises questions about fulfilling the needs of the local public to express their understanding and selection of cultural expression. This dissertation seeks to understand the tensions in the role of street art productions in Cape Town in place making, arguing that it can run the risk of being an expression of suppression, shaped by the graffiti by-law and approval procedures. The way street art is selected, commissioned, and regulated has become an expression of culture for the global market to consume for economic development, largely through tourism as opposed to representing local cultural expressions. Previous studies of street art in Cape Town have failed to address the tension in limiting cultural producers to solely express marketable street art for tourism over the needs of social change for local publics. To identify the tensions experienced by cultural producers in producing street art in Cape Town I have examined the trade-offs of two cultural producers in becoming active participants in dominating prime locations of walls in the Cape Town central business district areas: Baz Art and Urban Khoi Soldier. Using qualitative and visual methodologies, this research explored street art in Brazil and Cape Town. The Brazilian example shows a context of unregulated expression of plural political views and citizenship within a multicultural nation. The regulation of street art in Cape Town reveals new forms of cultural colonisation where cultural representation and narratives are dominated by a globalised framework of ‘Africanity'. Therefore, this research demonstrates the lack of a variety of multicultural expressions and forms of citizenship which robs the various publics of encountering meaningful ways of seeing and being in Cape Town.
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    Open Access
    The contribution of small-scale fisheries to the community food security of one South African coastal community
    (2019) Macdonald, Margaret; Battersby, Jane; Raemaekers Serge
    Small-scale fisheries contribute to the food security of a significant portion of the global population through direct consumption and indirectly as a vital source of income. Approximately, 50 million individuals involved in capture fisheries are small-scale fishers and they contribute to 80 percent of the global catch that is used for domestic consumption. Smallscale fishers provide their immediate communities with a vital source of protein. The sector enables an income source through full-time or part-time work to vulnerable coastal communities. In South Africa, approximately 28,000 small-scale fishers rely on marine resources for food security and livelihoods; however, continued marginalisation of small-scale fishers through discriminatory fisheries regulations favouring the large-scale fisheries sector and poor reallocation of access rights challenges the contribution of small-scale fisheries for community food security. While there is evidence that suggests small-scale fisheries in South Africa contribute to the food security of coastal communities, there is little know about the extent of the contribution as well as how the sector contributes to community food security and what factors influence community food security outcomes. The purpose of this research was to examine the contribution of small-scale fisheries to the community food security of one South African coastal community. Lambert’s Bay, Western Cape served as the case study and a mixed methods approach was employed to address three research objectives. Forty household surveys were completed at fisher and non-fisher households to examine the current level of household food security within the community and address the first research objective. Secondly, focus group discussions were completed with men and women to understand perceptions of food security and the food culture of the community. Lastly, the third objective was to examine the potential impacts of a reconfigured market on the local food system. This objective was addressed through a scenario planning workshop that was conducted with fishermen and women. This research utilised a community food security lens to broadly examine the role of smallscale fisheries to food security. Community food security is a holistic term that builds upon food security, food sovereignty and cultural food security but explores food security at both the household and community level as well as how outcomes are shaped by socio-economic, institutional and environmental drivers. The lens enabled the reframing of food security within the context of a fishing community and provided a scope to address the research objectives. Overall, Lambert’s Bay case study indicates high levels of food insecurity characterised by significant seasonal variation and low dietary diversity. Reported consumption of fish was relatively low; however, during the Snoek run, findings indicated consumption of fish throughout the community increased. Moreover, the Snoek season, is significant for its contribution food security indirectly as it provides livelihoods for many individuals. Historically, fishing activities and fish was a key aspect to the cultural identity of Lambert’s Bay. While fish remains a component of culture, the decline in traditional food ways associated with fish suggested a weakening of its cultural significance. Environmental, economic and institutional factors threaten the contribution of small-scale fisheries to the community food security of Lambert’s Bay. Most notably, poor governance in the small scale-fisheries sector has compromised the role of fish for food, livelihoods and culture. Secondly, environmental changes due to climate change and human activities reduce access and availability of fish for food and livelihoods. The key finding of this research was that small-scale fisheries contributes to the community food security of Lambert’s Bay through direct consumption and indirectly though the provision of livelihoods. Seasonality, unfavourable fishing conditions as well as the presence of Snoek, a migratory species, dictates the role of small-scale fisheries for food security. Poor seasonal fishing conditions negatively impacts the consumption of fish throughout the community as well as income for fishers. Conversely, the Snoek season provides critical livelihoods opportunities for community members and increased consumption of fish throughout the community. Environmental and institutional factors influence food security outcomes derived from small-scale fisheries. In addition, the prevalence of traditional food practices and the functionality of the social economy associated with fish is adversely affected by these drivers. This research contributes to scholarship within the small-scale fisheries and food security sphere as well as food systems research. It highlights the interconnectedness of various factors and the complexity of coastal food systems through the application of a community food security lens. A deeper understanding of the factors that influence food security outcomes in the context of fishing communities is advantageous as it can guide targeted research and initiatives that strengthen the well-being of fisher communities.
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    The functional ecology of Eastern Rûens Shale Renosterveld
    (2019) Cowan, Oliver; Anderson, Pippin
    Globally, ecosystems are under mounting pressure as biodiversity is lost at an ever increasing rate due to drivers such as habitat destruction and climate change. The systematic degradation of natural habitats witnessed today is often accompanied by a loss of ecosystem functioning and services which not only endangers the future of humankind but has consequences for all life on earth. To manage the ecological challenges facing us there is an urgent need to increase our understanding of how ecosystems function, the relation/ship between biodiversity and ecosystem functioning, and the effect habitat degradation can have on this relationship. Eastern Rûens Shale Renosterveld, located in the Overberg region of South Africa, is a vegetation type both critically endangered and poorly understood. Centuries of agricultural activity in the region has resulted in a landscape typified by fragments of pristine vegetation, in addition to communities in various states of degradation, embedded in an agricultural matrix. The current quantities of pristine vegetation are inadequate to meet conservation goals and conservation efforts are further challenged by the fact that little is known of the functional ecology of not only pristine fragments of Renosterveld, but the degraded communities in various stages of secondary succession. The overarching aim of this thesis is to better understand the relationship between biodiversity and ecosystem functioning across a degradation gradient in critically endangered Renosterveld vegetation within an agricultural landscape in South Africa. To achieve this, a variety of methods were employed using different lenses of analysis. In Chapter 2, I studied the components of biodiversity to assess the relationship between taxonomic and functional diversity indices and investigate the effect of habitat degradation. In Chapters 3 and 4, I used litter traps to investigate the effect of plant litter type, season and habitat degradation on litter decomposition rates and Springtail (Collembola) community dynamics, respectively. Finally, in Chapter 5, I constructed three high-resolution plant-pollinator networks from sites with distinct land-use histories and with different above-ground vegetation communities. The results revealed a complex association between different taxonomic and functional diversity indices, influenced by habitat degradation, with potential ecological and conservation implications. Particularly, the loss of functional redundancy in degraded sites is likely to reduce resilience to future environmental perturbations which may reduce ecosystem functions. Conversely, the similarities in both taxonomic and functional diversity indices between pristine and moderately degraded sites may be cautiously interpreted as the occurrence of successful passive restoration. Litter decomposition rates were shown to be variable with litter type and season revealed as important controlling factors. Although degradation did not appear to significantly affect iv decomposition rates, the initial nutrient content of litter appears to correlate with decomposition rate and it can be expected this ecosystem function will be accelerated where habitat degradation results in shifts in above-ground vegetation and subsequent litter input, specifically where the cover of non-native, nitrogen-rich annual species is increased. There was found to be a significant impact of litter type on community composition, and of sampling day on species richness, abundance and community composition, in Springtail communities. Despite the overall lack of effect of degradation on Springtail community dynamics, the abundance of the non-native Entomobrya multifasciata in degraded sites, and its absence from pristine sites, raises the intriguing possibility of its suitability as a bioindicator for habitat degradation. Comparisons to similar global studies revealed the Renosterveld networks to be highly functionally specialized. Assessing network dynamics across a degradation gradient showed the impact of above-ground vegetation structure on network properties with the more open and diverse vegetation structure and floral resources provided by the highly degraded site resulting in network indices more similar to that of the pristine site when compared to the relatively structurally uniform moderately degraded site. Although this thesis has enhanced our understanding of the functional ecology of Renosterveld, it has also highlighted knowledge gaps which still exist. Creating and collating a database of functional trait data can provide the building blocks for future ecological work. Furthermore, to truly gain a mechanistic understanding of the biodiversity-ecosystem function relationship one needs to utilise an integrated analysis which considers different facets of biodiversity, particularly functional diversity, across multiple trophic levels while simultaneously acknowledging the legacy effects that distinct land-use histories can impose at the community level.
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    The political ecology of community-based adaptation to flood risk in informal settlements: the case of a local community organisation
    (2018) Fox, Ashley; Ziervogel, Gina; Scheba, Suraya
    As urbanisation rates increase in parallel with growing climate change concerns, African cities are increasingly required to explore and support adaptation planning that reduces climate risks for the most vulnerable. Informal settlements are particularly vulnerable to climate change due to their high density, limited service provision, and a lack of economic and political opportunities for residents. In Cape Town, informal settlements face disastrous floods every year in the rainy season due to their location on degraded, low-lying lands as a result of Apartheid spatial planning. This thesis explores how multi-scalar governance in Cape Town can either empower or undermine efforts at community-based adaptation (CBA) to flooding in informal settlements. Drawing on urban political ecology, this thesis assesses the potential for CBA to lead to wider transformation. Using a case study approach, it focuses on the informal settlement network (ISN), a community-based organisation of the urban poor. ISN members and other actors involved in flood management in Cape Town were interviewed to understand the flood management landscape and the relationships and dynamics that exist between the various actors. The analysis showed that the CoCT’s efforts at participatory planning reinforce the hegemonic power dynamics between government and communities, but that everyday governance practices can be used at a smaller-scale to enforce positive change. In reaction to top-down governmental processes, ISN uses insurgent planning to envision a more just city. They navigate sanctioned and un-sanctioned spaces of citizenship to drive development from the bottom-up. The community designed and spearheaded reblocking process (rearranging shacks in a settlement to allow for flood drainage and service delivery) is a powerful example of CBA and represents the potential of communitybased organisations to take steps towards transformation. In order to enable true transformative CBA, both the CoCT and ISN need to adjust the epistemological framing of their planning processes in order to address the drivers of vulnerabilities, rather than just the vulnerabilities themselves.
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    Tolerating climate change: a study on the influence of thermal history on thermal tolerance of Galaxias zebratus in rivers of the Cape Peninsula, South Africa
    (2018) Olsen, Toni; Dallas, Helen; Shelton, Jeremy; Reed, Cecile
    Global climate change models predict a reduction in rainfall and rise in air temperature for the Cape Peninsula of South Africa’s Cape Floristic Region (CFR). The CFR is a biodiversity hotspot renowned for its high level of floral endemism, but the high level of endemism also applies to the region’s freshwater fish assemblage. Whereas the current threats to endemic freshwater fish include habitat modification, water abstraction, pollution and impacts of non-native species, climate change is predicted to further exacerbate negative impacts on fish communities. The endemic CFR fish species, Cape Galaxias, Galaxias zebratus Castelnau, 1861, is widespread throughout the region, and occurs in both non-perennial and perennial rivers, and wetlands. The species is thought to be a relict group of ancient species originating from the break up of Gondwanaland 180 – 135 million years ago. Endemic CFR freshwater fish, like G. zebratus, may be sensitive to the thermal regime of their environment and may thus be influenced by climate warming. The most commonly used experimental approach for determining the effect of elevated temperature on freshwater biota is the Critical Thermal Method (CTM). The CTM determines the upper thermal tolerance limit or critical thermal maximum (CTmax) of a species. Thermal history is the range of temperatures experienced by an organism in its natural habitat over time and this may be an important factor determining the thermal tolerance of species. The aim of this study was to evaluate the influence of thermal history, reflecting a stream’s thermal profile, on upper thermal tolerance limits of G. zebratus. We hypothesised that G. zebratus from warmer sites would have a higher CTmax than individuals at cooler sites. To examine the influence thermal history has on the thermal tolerance of G. zebratus, hourly water temperature data were collected and the CTmax values were determined for fish (n=30 per site) from 10 different sites in rivers of the Cape Peninsula. The CTmax values from all sites for the November-December experimental period ranged from 30.00°C to 32.45°C. CTmax values for all sites from the JanuaryFebruary experimental period ranged from 31.29°C to 33.42°C. Upper thermal tolerance limits of G. zebratus increased from the November-December experiments to the January-February experiments. Regression analyses show that G. zebratus upper thermal tolerance limits are significantly influenced by its thermal history as characterised by the seven day moving average of daily mean (Mean_7) two weeks preceding the experiments, implying that changes to the thermal regime will influence the thermal tolerance of G. zebratus. The resultant regression equation allows G. zebratus CTmax to be predicted by thermal history based on Mean_7, providing valuable information to set thermal limits of G. zebratus and guide future research. This is the first study on the thermal ecology of G. zebratus in the CFR and in Africa. The data not only enhance understanding of the thermal ecology of the species, but also further our understanding of their potential vulnerability to climate change.
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    Understanding the resilience of local seed systems: a case study of Uzumba-Maramba Pfungwe and Chimanimani Districts, Zimbabwe
    (2021) Kusena, Kudzai; Wynberg, Rachel; Mujaju, Claid
    Globally, industrial crop production practices are of significant environmental concern, with some studies suggesting that smallholder farming systems could provide a more sustainable alternative. Local seed systems are at the core of smallholder agriculture and, although typically characterised as inefficient, can account for 60-100% of seed materials planted. Such systems are envisaged to remain as dominant seed sources in the foreseeable future, especially in the face of climate change and socio-economic challenges. However, there is a limited understanding of how local seed systems persist in the face of adversities. In this nexus, local seed systems are seen as key areas for enhancing resilience as they have strong links to food security and livelihoods in smallholder farming communities. Based on case studies from Zimbabwe, a country with more than 70% of its population dependent on smallholder agriculture, and a prolonged history of acute economic and ecological challenges, this study examines the concept of resilience in smallholder seed systems. The research aimed to explore interactions between the management of seed by smallholder farmers and social and ecological factors to understand their influence on the resilience of local seed systems. The history of local seed systems in Zimbabwe is explored, as well as the constraints faced by smallholder farmers and the innovations they have developed. The research characterises the activities of smallholder farmers and the quality of seeds circulating in local seed systems and examines how actors and institutions shape such characteristics. Building on critical theoretical debates around social-ecological systems, complex adaptive systems and resilience, an analysis is provided of how local seed systems interact with social and ecological factors, thus developing a conceptual understanding of how resilience is enabled or constrained in these systems. Case studies were selected in the Uzumba-Maramba-Pfungwe and Chimanimani Districts of Zimbabwe. Using an interdisciplinary research approach, qualitative and quantitative data collection methods were used, including household surveys, key informant interviews, participatory observations, and laboratory experiments. The findings show that history profoundly influences the social and ecological factors affecting local seed systems and informs how smallholder farmers have sustained these systems in the face of adversities. The innovations of smallholder farmers are emphasised alongside the repertoire of seed management options they used to respond to social and ecological adversities. Although traditional cultural practices to sustain local seed systems are waning, other forms of institutional arrangements driven by non-govenmental organisations are emerging, such as seed fairs, field days and community seed banks. These emergent activities have provided new platforms that promote local seed systems. Formal seed systems do not offer such opportunities, as they operate in a rigid, predetermined and highly regulated manner. However, an increased focus on local seed markets may conflict with traditional norms that view seeds as common heritage assets openly exchanged among farmers. A central premise is that local seed systems are shaped by non-linear and complex interactions of nested ecological and social factors. The demonstrated resilience behaviour of these systems challenges the appropriateness of prescriptive and mechanistic interventions such as seed aid. Ten key principles are proposed that characterise the resilience of local seed systems. The thesis emphasises the importance of integrating the principles into policy and practice to advance seed and food security of smallholder farmers.
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    The values of nature: personal narratives of conservation in South Africa
    (2016) Cresswell, Naomi Jayne; Daya, Shari
    This dissertation explores the values of nature through the personal narratives of landowners in the Overberg area of Western Cape, South Africa. In the past, scholarly literature has imagined nature as separated from the human world. Historically, mainstream conservation methods have followed ideals of nature in forming environmental management policies and practices, aiming to create and maintain an isolated nature. This ideal of nature has largely ignored the roles of humans within the environment. A range of new fields of studies around identity, business and politics explore new ways of imagining nature, focusing on the human within nature and the nature within the human. Using these alternative imaginings, this research uncovers a variety of ways 'humanness' and nature are deeply embedded within each other. This research challenges the ideal of a pristine otherness whilst both supporting and filling in the gaps of contemporary alternative literature. The personal narratives of 34 landowners were gathered during 10 weeks of fieldwork. These stories offered an alternative portrayal of the relationship between humans, nature and conservation. Landownership was more than business as usual; land embodied deep and meaningful emotions, experiences and discourses of daily human life. Landscapes embodied personal emotions of owners through shaping their identities, spirituality, belonging and family histories. Dynamics of politics manifested in different forms such as fear, mistrust, corruption and exclusion throughout landowner's experiences and attitudes. These political factors, emotions and economic dynamics play a role in shaping landowners' attitudes, resistances and participation both towards conservation as well as nature, in turn influencing the way they organise themselves in relation to conservation bodies such as government run programmes as well as NGOs. It also affects how they organise, negotiate and manage themselves and their land. Conservation management of land should take into account these deeply complex, multidimensional and integrated complexities entrenched within daily narratives of landownership.