3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Assessing the link between rural food security and rangeland woody biomass in Limpopo(2017) Evans, VeroniquePeople living in rural areas are directly dependent on the local natural resources. The continued unsustainable use of natural resources leads to woodland degradation, through changes in vegetation structure. If the integrity of a rangeland is compromised, then so would the quality and quantity of provision of ecosystem services such as wild fruits, firewood and medicinal plants that rural households rely on. This in turn threatens the food security of rural communities. Changes in woody biomass and vertical vegetation structure is a consequence of resource extraction in human utilised landscapes. This study aims to enhance the understanding of the role that above ground woody biomass plays in rural South Africa, focusing specifically on the impact that the state of the woody biomass has on surrounding communities’ food security. The study site was four villages in the Lowveld of Limpopo province: Mafarana, Ga-Selwana, Vyeboom and Ka-Ndengeza. The research assessed woody biomass and vertical vegetation structures, as a proxy for provisioning ecosystem services. I used LiDAR (Light Imaging Detection and Ranging) to measure vegetation structure and estimate biomass in the communal rangelands of these four rural villages. The average rangeland canopy cover and average rangeland biomass of the four case study villages was not influenced by the village settlement areas (size of the village). At the rangeland-scale across the four villages, anthropogenic influences on biomass and vegetation structure were evident. This is particularly true for the biomass in Ka-Ndengeza and Ga-Selwana villages where the spatial trajectory of biomass increased with increasing distance from the village settlement as well as the nearest road. High levels of anthropogenic disturbance were evident in Mafarana’s rangeland, where the biomass gradient was bimodal (had two maximum points), and levels of human disturbance was evident at increased distances from the village settlement and the nearest road. Having explored the impacts that rural households have on the biomass of their communal rangeland, this study then aimed to explore the cost associated with collecting firewood. The access to fruiting trees was explored as 97-100% of all households were reported to use this resource. Based on the examination of the cost pathways on a finer scale, slope and shrub cover only factor in at the end of a pathway. Moreover, the least cost pathways value is that they show that accessing a resource is not uniform, as multiple factors influence this access. This study found that, the cost to access a natural resource does not increase with increasing distance iii from the village settlement as described in the “Central Place Theory” and Piosphere Theory and that there are multiple factors influencing accessibility. This research highlighted the impact that human utilisation can have on woody resources and vegetation structure in communal rangelands. After establishing the effect of resource extraction on vegetation structure, the study goes further to explore the links between rangeland integrity and food security. This was done with household interviews that were conducted with the person responsible for household tasks, across the four case study villages in Limpopo, South Africa. The household survey consisted of 28 questions, divided into five categories. The first two sections focused on collecting information regarding the household characteristics, income and expenditure. The following section focused on the use of the suite of local natural resources. The questionnaire also focused on describing the source of the fuelwood used within the household, whether the fuelwood was purchased or collected, species preference as well as perceived declines or increases in fuelwood availability. The questionnaire also explored food security and nutrition, food shortages and the diet of interviewed households. The most commonly utilised resources were firewood, wild vegetables and wild fruit which were used across all four study villages. This study found that virtually all the households, across all four villages used firewood, wild fruit and wild vegetables. Despite this that some households are clearly more vulnerable to food insecurity than others. Ga-Selwana was the only village that had no households that experienced hunger all the time. Mafarana and Vyboom had the highest proportion of households that did not experience any food shortages in the last year. The results from this study suggest that improved food security might be associated with a healthier state of the communal woodlands, but more detailed analysis of where the relationship exists needs to be explored. This study found that the resource use and the associated disturbance gradients are settlement specific, which highlights the value of settlement specific studies that incorporate local information is. It is expected that the disturbance gradients evident in this study will begin to diminish and merge around the settlements as the future vegetation structure becomes more homogeneous. The intensive use of nature resources evident in this study suggest impending, if not already occurring, sustainability issues. Repeated data collection is required to assess and monitor the changes in woodland structure and biomass as well as change in patterns of rangeland use as natural resources decrease.Item Rationale for choice of fuel use by poor communities: a study of Ramaphosa Informal Settlement(2016) Doro, Thanduxolo LawrenceThis study examines use of different energy sources by a poor community of the Ramaphosa Informal Settlement in Gauteng Province, South Africa. The purpose of this study was to investigate the reasons behind continued use of biomass fuel (plant or animal material, wood, charcoal) for cooking and space heating by poor residents. The research questions are: What informs the informal settlement residents’ use of certain energy sources for cooking and heating over other types? Where residents possess knowledge of the harmful effects of continued use of an energy source, yet continue to use it, what are the reasons for this? Whose responsibility does it become to collect a chosen energy source, and how is it collected? The consequences of indoor air pollution vary from short-term – eye and throat irritation – to long-term effects – respiratory disease and cancer. Exposure to high levels of some pollutants, such as carbon monoxide, can even result in immediate death. An exploratory empirical research was performed using mixed qualitative and quantitative methods using data on time-activity patterns collected from eleven households by means of semi-structured interviews, observations, focus group discussions and expert interviews. The results show that the respondents in the researched areas of Reserve and Extension two in Ramaphosa Informal Settlement use a total of thirteen different energy sources to meet their fuel needs. Although possessing the necessary knowledge on negative effects of indoor air pollution, the respondents lack sufficient resources to make decisions that would help improve their conditions regarding effects of air pollution. In thirty of the fifty respondents women and girls collect fuel and only in the remaining twenty wherein electricity, paraffin and liquid petroleum gas (LPG) are used, do men and boys become responsible for fuel collection. In the absence of electricity, respondents reported preferences for LPG, however, the prohibitive costs of the capital outlay of the latter energy source makes it unaffordable to more than half of the respondents. The major finding in this report is that whilst some of the respondents think that electricity remains a key barrier to improving their socio-economic development and well-being, twenty of the fifty respondents who exclusively rely on government grants do not think so. Electricity, although an absolute necessity in the researched areas, is not a sufficient condition for avoidance of effects of indoor air pollution for the poor communities. This was demonstrated by the five respondents who have electricity but alternate its use with coal and firewood. The high cost of electricity means that poorer communities will continue to rely on the less expensive bio-mass fuel – risking their lives in the process – even when electricity is available. Respondents reported difficult conditions under which they live which are shaped by broader sets of unresolved structural aspects in the form of economics, social policies, and politics.Item Risk assessment of above ground biomass for fuel use in eucalyptus species cultivated on acid mine drainage in the Witwatersrand Basin gold fields(2016) Mosito, Nosipho Sylvia VanessaSouth African gold mines are associated with the generation of a lot of mine waste in the form of milled rock (tailings). Tailings contain the mineral pyrite which, when exposed to air and water, cause acid mine drainage (AMD). Due to the large environmental impact (footprint and scale) ofthe tailings storage facilities (TSFs) on soils and groundwater, there has been much research done in phytoremediation. Some plants, such as Eucalyptus, used in this method are able to control seepage by using their extensive roots but this may inadvertently extract some contaminants from the water and accumulate them in the above ground parts of the tree. Upon harvesting of these plants, there is the potential for them to be used as biofuel for the generation of bioenergy, and by industry or the public as timber/construction wood, firewood, charcoal, generation of electricity, etc. In this study, three species of Eucalyptus trees grown by the University of the Witwatersrand in three site-species trials on AMD were evaluated for their concentrations of elements in leaves, bark, branches/twigs and stem wood, in order to determine the safety of the biomass for fuel, and the potential for environmental pollution (dissemination of metals) that could be caused by combustion. The study focused on Eucalyptus camaldulensis, E. grandis x camaldulensis hybrid and E. dunnii trees grown for eight years in three different trial sites, with one trial ("Mispah") situated at AngloGold Ashanti's Vaal River Mining Operations (VR, near Orkney - Klerksdorp) and two trial("Madala", "Red Soil") situated at the West Wits Mining Operations (WW, near Carletonville). The sites were typical of soils on the mine properties (WW Madala: Clovelly, WW Red Soil: Hutton, VR Mispah: Hutton and Mispah), and impacted by seepage from adjacent TSFs. Three entire above-ground trees were harvested per species (three trees per site, nine in total), weighed fresh and after drying. Samples of leaves, bark, twig/small branches, and main stem wood were analysed for their elemental contents; alongside a Certified Reference Material (CRM) (Orchard Leaves no. 1571); using Leco CNS analyser, Inductively Coupled PlasmaOptical Emission Spectroscopy (ICP-OES) and Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) to determine the concentrations of major and trace elements such as Aluminium (AI), Barium (Ba), Calcium (Ca), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Sodium (Na), Nickel (Ni), Phosphorus (P), Sulphur (S), Strontium (Sr), Titanium (Ti), Zinc (Zn), Vanadium (V), Chromium (Cr), Cobalt (Co), Copper (Cu), Arsenic (As), Gold (Au), Mercury (Hg), Lead (Pb), Uranium (U), carbon (C) and ash content. The CRM was used to validate the two analytical methods. There was variation in the concentrations of nutrients measured. There were no significant differences noted in the metallloids concentrations between all the Eucalyptus 11\ species studied (p>O.05). Variation between sites could not be determined as there were no replicates available to perform the comparison. The World Health Organisation (WHO) maximum permissible level (MPL) in plants for arsenic (As) is 1 mg/kg. The MPL was exceeded in all tissues of all three Eucalyptus species studied. Arsenic concentrations of 5.09, 4.36 and 5.48 mg/kg were found in the wood of E. camaldulensis, E. grandis x camaldulensis and E. dunnii respectively. A risk assessment performed found that there was no evidence that there will be adverse effects caused by supplying fuelwood from these contaminated Eucalyptus trees. Even though high arsenic concentrations were recorded in this study, if the wood is used as fertilizer in a vegetable bed, the transfer of the arsenic to the common vegetables is below the daily oral reference dose. The general trend in the concentration of metals and metalloids in different plant tissues was in the order of leaves > bark > branches/twigs > wood. The results of the biomass exposure assessment showed that the exposure through use of the ash as fertiliser was lower than the oral reference dose for Mn, Fe, Ba and As. The biomass risk assessment showed that the best-performing tree, in terms of wood production on AMO, was the E. camaldulensis. The risk of other metallioids was not evaluated as there was no good agreement between the results recorded with those certified of the CRM. It is suspected that the CRM used was old.