Browsing by Subject "Geographical Sciences"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Open Access
    A CMIP5 Model Selection Specific to South Africa's Winter Rainfall Zone
    (2022) Marsh, Peter; Jack, Christopher
    This study undertakes a CMIP5 model selection specific to the Winter Rainfall Zone (WRZ) of South Africa, seeking to reduce the range of future climate projections through identifying a subset of models with increased realism and independence. In order to navigate the subjectivity in identifying relevant circulation metrics to assess models against, the ‘Day Zero' drought is used as a characteristic episode. Here initially the extensive literature produced subsequent to the drought has been drawn on to identify and evaluate relevant regional process metrics, before utilising the anomalous conditions during the drought to validate various assessment methods. The dynamics subsequently identified as being most influential to rainfall supply in the WRZ include the South Atlantic subtropical jet stream responsible for steering of mid-latitude storm systems, the South Atlantic subtropical high, and the presence, or preferably absence, of precipitation blocking subsidence, and the prevalence of mid-latitude storm systems, critical for transport and upliftment of moisture to the region. Models were subsequently assessed against these metrics and scored following the technique of McSweeney et al. (2015). Unrealistic models were removed from the ensemble while significantly biased models were also excluded as their absence did not significantly reduce the range of future projections. The same scoring methods were then utilised to create a genealogy of models attaining similar results to that of Knutti, Masson & Gettelman (2013). A subset of 6 CMIP5 models which are more independent and historically more realistic than that of the full ensemble were subsequently identified. While the range of future temperature projections of the final ensemble are somewhat constrained in comparison to the full ensemble, the primary utility is argued to be the reduced number of models where a future researcher may consider each model's projected future climate pathway individually before selecting a model, or models, which best informs their use case, whilst being assured that this model performs suitably well in the region and that the initial ensemble considered adequately represents model uncertainty, while strong similarity between two or more models within the ensemble will not be unduly biasing results.
  • Thumbnail Image
    Item
    Open Access
    Change begets change: employing a change perspective to inform South Africa's coastal community conservation policy-praxis disjuncture
    (2021) Rice, Wayne Stanley; Sowman, Merle; Bavinck, Maarten
    Contemporary biodiversity conservation is ‘wickedly complex'. This complexity stems from the need to address the diverse objectives of protecting biodiversity and enhancing social wellbeing. However, centralized and exclusionary conservation approaches are often ill-suited to tackling these coupled objectives. Consequently, increasingly calls have been made for the development of more holistic, participatory, nuanced and context-specific conservation governance approaches. Community-based conservation – which seeks to include local communities and their knowledge and priorities in conservation governance – offers a viable though context-specific alternative. However, thus far communitybased conservation initiatives have produced mixed results, largely due to a lack of understanding of how to effectively initiate, implement and manage such ‘wickedly complex' conservation initiatives. South Africa possesses enabling legislation for community-based conservation, but to date there has been no implementation of legally recognized communityconserved areas in the coastal zone. Accordingly, this research is guided by a desire to better understand this ‘policy-praxis disjuncture', and explores what factors, conditions and processes are required to enable South Africa to embrace a more community-orientated approach to conservation. It is proposed that greater understanding and potentially success can be gained by viewing communitybased conservation including, the initiation, implementation and governance of community-conserved areas, as a ‘change process'. Drawing on Commons Theory, Governance Theory, and the Theory of Change approach, a framework was developed to guide the exploration of the factors, conditions and processes that enable the shift to a community-based mode of conservation governance. Case study investigations were conducted in two established regional community coastal conservation cases, and one South African ‘case-in-progress'. Based on the findings of these cases, and the perceptions of South African conservation actors, this dissertation offers insights for tackling South Africa's policy-praxis disjuncture by developing a South African Empirical Community-Based Conservation Theory of Change Pathway. By exploring the initiation, implementation and governance of community-based conservation initiatives as a change process, this dissertation provides a framework for designing a process to facilitate and implement community-based conservation where contextually appropriate. More specifically, it emphasizes the need to develop a context-appropriate, strategic, systematic and iterative set of actions, with clearly articulated assumptions, which strive to address present or potential issues, to support the change to community-based governance. Consequently, this dissertation provides a framework for understanding how a shift to a community-based mode of conservation governance takes place, and offers a South African specific design pathway, with potential application by diverse conservation actors in other countries.
  • Thumbnail Image
    Item
    Open Access
    Nutrient loading in the Vaal River over the past two decades
    (2019) Ntshalintshali, Pargeant; Winter, Kevin
    Nutrient loading is negatively affecting South Africa’s freshwater resources and ecosystems. Anthropogenic activities are the leading causes of continuous nutrient loading in the country’s water resources. This study examines the dynamics of nutrient loading in the Vaal River. The objectives are to explore nutrient loading in the Vaal River over the past two decades and to compare the differences between the two decades. Water quality data were obtained from the Department of Water and Sanitation (DWS) Water Resource Quality Information Services (RQIS) database. Elevated nutrients of NH4+, N03, P04 3- and chlorophyll-a were observed at selected sites at various times during the 20 year period under analysis. Nutrients concentration are elevated alongside agricultural and industrial activities, and urban areas. Student t-tests investigated the difference between the two decades and in most cases showed significant differences between these decades. The last decade showed elevated nutrient levels for N03, NH4+ and chlorophyll-a in most of the DWS monitoring sites. Only P04 3- at some sites showed a reduction from the previous decade. The study concludes that upper and middle sections of Vaal River are eutrophic and hypertrophic and a trend toward a permanent state of these conditions is likely without a long-term solution to address the problem of excessive nutrient loading entering the Vaal River system.
  • No Thumbnail Available
    Item
    Open Access
    Phytolith Analysis as a Palaeoecological Tool for Reconstructing Mid-to Late-Pleistocene Environments in the Olorgesailie Basin, Kenya
    (2012) Kinyanjui, Rahab; Meadows, Michael; Gillson, Lindsey
    Olorgesailie Basin is an important prehistoric locus and holds a prominent place in African Quaternary research. It is located in the southern Kenya rift system (1˚ 35´S and 36˚ 27´E) and has preserved numerous archaeological findings of the Acheulean, Sangoan and Middle Stone Age occupations and most importantly, hominin cranium associated with the Acheulean hand axes. Evidence of past vegetation has hitherto been scarce, because the arid / semi-arid conditions are not conducive for preservation of organic plant microfossils. Phytolith analysis is used to reconstruct the vegetation history and understand hominin habitat preference during mid-late Pleistocene (~746-64 ka). A localised modern phytolith analogue is used to interpret the fossil assemblage. Descriptive analysis identified fifty nine phytolith morphotypes which were categorised into three major groups; grass short-cell phytolith, epidermal silicified appendages and sedge phytoliths. The identification and classification was based on the International Code for Phytolith Nomenclature and other existing literature. In order to determine the significance of the identified morphotypes in interpreting fossil data, two multivariate statistical analyses were performed on the database; Correspondence analysis distinguished vegetation components according to a moisture gradient while Cluster analysis identified unique morphotypes that were taxonomically affiliated to their parent plant species. However, the analyses were not able to distinguish plants along the altitudinal gradient. Fossil phytoliths derived from sixty palaeosol samples extracted from eight geological sections in three localities of the Olorgesailie Basin, were identified and tallied to determine vegetation cover and how this changed both spatially and temporarily during the mid-late Pleistocene period. Fossil phytolith frequencies were plotted on TILIA diagrams against the available 40Ar/39Ar dates. Correspondence analysis identified three vegetation components; grasslands, woody & herbaceous and aquatic and identified moisture availability as the major underlying factor influencing the morphotype clusters on the ordination space. An additional cluster analysis of forty morphotypes derived from grasses confirmed the known taxonomic affiliation of major grass short-cell phytoliths to four grass subfamilies (saddle ovate- C3 Arundinoideae, bilobate concave- and convex- outer margin short shaft and quadralobate-C4 Panicoideae, saddles-C4 Chloridoideae and bilobates convex outer margin long shaft-C4 Aristidoideae). From the non-grass category, achene and papillae phytolith morphotypes were identified as belonging to the Cyperaceae.
  • Thumbnail Image
    Item
    Open Access
    Transboundary landscapes and rural livelihoods: a case study from the northern Kwazulu-Natal and Mozambique border
    (2021) Mahlaba, Simlindile; Mbatha, Philile
    Transboundary landscapes were introduced to southern Africa through colonialism and persist in the present day. These transboundary landscapes are constructed through political boundaries separating states as well as through the linkage of nature reserves and game parks located in adjacent countries. These landscapes have caused shifts in the livelihoods of the rural communities existing near them. This is the case for the Mbangweni rural area in northern KwaZulu-Natal in South Africa. This rural area, located in a transboundary landscape formed by the national border that separates Mozambique and South Africa, sits in between Ndumo Game Reserve and Tembe Elephant Park. The proposed linkage of these two nature reserves to each other and to the Maputo Special Reserve in Mozambique seeks to create a transboundary landscape that has negative consequences for the livelihoods of the Mbangweni community. Through the analysis of this rural community and the nature reserves on either side of it, this research sought to enhance understanding about how rural communities interact with transboundary landscapes, as well as the perceptions held by these rural communities and other actors (especially within the conservation sector) about how these landscapes influence rural livelihoods as well as the consequences of these landscapes on rural livelihoods. The study sought to also understand the level of institutional fit and interplay that exists between the institutions that govern over this landscape as well as between the institutions and the lived realities of the Mbangweni community by documenting the historical and current transboundary livelihood practices of the people of Mbangweni, determining the manner in which government actors and conservation authorities perceive and conceive of the transboundary landscape, determining whether or not (and to what extent) local and government perceptions about the transboundary landscape in Mbangweni are similar, and if not, how that affects livelihood activities on the ground and visually mapping out the different perceptions of the landscape held by the Mbangweni community and associated governing institutions. Qualitative data collection methods were used. These included 10 oral history interviews, 2 focus groups and 3 key informant interviews. The findings of this study reveal that the initial establishment of the transboundary landscape in this region led to the separation of the population of the Maputaland. The communities in northern KwaZulu-Natal and those in southern Mozambique once lived as a single population group. The national border separating South Africa from Mozambique was introduced and forced some of the population to settle on one side of the border and the rest on the other side. Although initially very rigid, the border's laws now allow for the informal movement of people and trade of goods between the southern Mozambique and northern KwaZulu-Natal areas. The study, therefore, found that the border's porous nature had a positive impact on the livelihoods of the people of Mbangweni. The findings also revealed that in addition to the national border, other institutions and entities were considered important for the livelihoods of the community. These institutions and entities include the traditional authority, the local municipality and the nature reserves adjacent to the Mbangweni community. These key role players each contributed to and impacted the rural livelihoods with the traditional authority having the biggest influence and most positive impact, the local municipality having the smallest influence and not much of an impact and the nature reserves having relatively minimal influence on the daily conduction of livelihoods but the most negative impact on how these livelihoods are conducted and sustained. Furthermore, the study showed that the key role players hold differing perceptions of the landscape and that these perceptions also differ from those held by the Mbangweni community. The study showed that the disconnect in perceptions of the landscapes results in isolated and fragmented land use by the entities and institutions occupying the same space. Conflict then arises due to the entities understanding and viewing the landscape as a space for different priorities. The nature reserves and their governing institution prioritise natural resource conservation and the Mbangweni community and the traditional authority, as its governing institution, prioritise their livelihoods and access to natural resources. These differing perceptions of the landscape perpetuate the institutional misfit and lack of interplay between the entities and governing institutions. The study found that even with different understandings of the landscape they occupy, each entity and relevant governing institution have the potential to facilitate institutional bricolage which would require adjustments of and changes to their mandates and goals to accommodate the mandates and goals of other institutions, other entities as well as the lived realities of the Mbangweni community. By fostering this bricolage, a transboundary landscape that adequately serves the needs and purposes of all its entities, whilst minimising opportunities for conflict between them, would be created.