This thesis explores the utility of the MM5 regional climate model iii product big a detailed wind climatology for South Africa in the context of wind power applications. Given the background of limited available computational resources a sophisticated temporal subsetting algorithm is developed and applied. The goal here is to allow a high resolution 18 by 18km simulation to be carried out over only 365 days of historical records (20 March 1996 until 19 March 1997), yet ensure that it is possible to construct a reasonably accurate climatology from such a short time period because it represents the most typical year available. Throughout the research the model's sensitivity towards different boundary layer and cwnulus parametrisations as well as observational and grid nudging is investigated in depth. New error metrics are specifically designed and applied based on 17 reliable lOni weather stations around the country with the specific purpose of evaluating model skill with respect to the wind patterns that are important for wind turbines. An optimal model configuration is established by using the Pleim Xiu land surface scheme coupled with the Atmospheric Convective Model for the planetary boundary layer, in addition to the Kain Fiitsch II cumulus parametrisation and observational wind nudging. The model is then integrated at 18km for the entire country and the results validated in detail. It is found that average wind speeds are within 0.2 + 0.7ms (68% confidence interval) and that the daily cycle, which constitutes the largest part of the observed variance, is predicted to within 18% + 20% of amplitude and lii of timing at coastal sites.

In arid southern Africa, many rivers are ephemeral, and surface flow occurs for less than 10% of the year. Floods, which occur erratically, recharge groundwater resources on which riverine vegetation depends. Trees and shrubs are the most common life forms along these river systems, because surface flows are too erratic for aquatic organisms to flourish. There is concern that alterations to the current water regime of ephemeral rivers will affect the distribution of riparian vegetation as trees provide valuable fodder, shade, firewood and construction material in otherwise inhospitable surroundings. Climate change, population growth and development needs all place growing pressure on these water-limited ecosystems. Careful catchment management is essential to meet human water needs without jeopardising the ecosystems. This is easier said than done however, as ephemeral river ecology and functioning are hardly understood. Their unpredictable hydrology, strong groundwater association, often remote location and the presence of large terrestrial life forms make ephemeral rivers difficult to understand and current âEnvironmental water allocationâ methods for wetter systems are unsuitable. Alternative methods are being developed, but to date they still have a strong emphasis on aquatic life forms and riparian vegetation is still insufficiently addressed. This study provides an ecophysiological perspective on the water sources and drought tolerance levels of four key riparian tree species in Southern Africa. The aim is to contribute to an improved understanding of the interrelationships between river flow, groundwater and use of water by trees. Stable Hydrogen and Oxygen isotope results show that the three key species along the Kuiseb River (Acacia erioloba, Faidherbia albida and Tamarix usneoides) do not take up any water from the regularly occurring fog events. Instead, they depend on a seasonally fluctuating mix of shallow and deep soil moisture as well as groundwater. All these water sources rely on regular recharge from floods. It suggests that reductions in flood frequency and especially in magnitude and duration will reduce groundwater recharge and affect species productivity and survival. It was investigated why A. erioloba, growing in the presence of the alien Prosopis glandulosa, show high mortality rates. The study used stable 2H, 18O and 13C isotopes, xylem pressure potentials and percentage canopy dieback to conclude that within the riparian zone, the two species depend on the same water sources and that indigenous A. erioloba are 2 significantly more water stressed when growing alongside P. glandulosa. Further inland A. erioloba is entirely groundwater dependent while P. glandulosa seasonally switches between water sources. This resource partitioning is advantageous for A. erioloba, which does not display the same levels of water stress as in the riparian zone. An investigation into the physiological structure, including wood density, xylem vessel diameters and xylem vulnerability to cavitation for all four species showed that A. erioloba was structurally the most drought tolerant. This finding corresponded well with its high survival rate in the 1980s Namib drought. In the Kalahari, however, it is still outcompeted by P. glandulosa, suggesting that the invasive species has a competitive edge over A. erioloba that goes beyond xylem structure. P. glandulosa and T. usneoides are similar in structure. F. albida is structurally the most vulnerable of the species, supporting the high mortality rates observed in the 1980âs. Water sourcing using stable Hydrogen and Oxygen isotopes, xylem structure and phenology were compared for three A. erioloba stands with access to different groundwater depths (4 m, 21 m and 56 m). The aim was to determine whether A. erioloba physiology changed proportionally to groundwater depth. Results show that A. erioloba structure and phenology do respond proportionally to groundwater depth, suggesting that A. erioloba can reach deep groundwater, but that this comes at a cost of increased water stress and reduced vitality. Ttrees depending on deep groundwater may thus be closer to a water-induced survival threshold than those growing with access to shallower groundwater. Catchment managers should carefully weigh up the benefits of new water developments relative to potential losses of this ecologically and economically important species. As the final objective and synthesis this study aimed to evaluate if any of the studied species could be used as a bioindicator for tree health in relation to water availability. T. usneoides was previously observed to be less tolerant to drought conditions than F. albida and A. erioloba, while this study has shown F. albida to be structurally the most vulnerable. Hence no bioindicator could be indentified and it is concluded that the determination of drought tolerance and the identification of one or more bioindicator species for future monitoring is a complex matter that needs to include more structural studies and field documentation during drought. 3 Ultimately the use of indicator species and investigations into water sourcing as well as drought tolerance studies should inform catchment management and be included in future assessments of environmental water requirements (EWR) methods and river health. This study concludes that several of the methods applied in this study (shoot growth measurements, percentage canopy dieback, wood density, δ2H, δ18O and δ13C stable isotopes, xylem pressure potentials and xylem vessel diameters) are worth applying in in a EWR in conjunction with groundwater and flood (volume, duration and height) measurements. This will require a shift from a traditionally aquatic outlook to one that is more inclusive of terrestrial ecology. More interdisciplinary cooperation and lateral thinking between aquatic and terrestrial ecologists is crucial, so that the frequency, magnitude, predictability and duration of floods and associated groundwater recharge are assessed in terms of water needs of woody riparian species as well as the associated terrestrial fauna.

Includes bibliographical references (leaves 130-139). / This research project attempts to determine the relative influences of climate, sea level changes and human activities during the period of sediment accumulation in the Noordhoek basin in the southwestern Cape. South Africa. The research relies on lacustrine sedimentary deposits and their compositional changes as evidence of the dynamic depositional environments from which environmental conditions are inferred. Data on spatial changes on land surfaces have also been employed to complement the sedimentary chronology from catchments beyond historic records. Assessment of the extent of human influence on the Noordhoek basin has been achieved through comparison with the pristine conditions found on the Cape Nature Reserve. Analysis of dated sediment cores from the Noordhoek valley and the Cape Peninsula Nature reserve has facilitated the reconstruction of major environmental changes for the late Pleistocene and Holocene periods. An extended record of environmental change from the longest core (LM-Core) has enabled environmental reconstruction and the determination of the relative influences of climate, sea level change and human activities on the local! environment of the basin during the late Quaternary. Sedimentological evidence from the cores reveals the long-term evolution of the wetlands as being influenced by fluctuating sea levels and climate change until the mid-Holocene. Short-term environmental processes during the late Holocene. resulting from direct anthropogenic activities such as irrational uses of the wetlands for agriculture and urbanisation are responsible for polluting and transforming the status of the wetlands. Heavy metal concentrations in sediment cores from the two Noordhoek wetlands have allowed the elucidation of recent human impacts. The vertical distribution of these metals correlates with and complements the evidence of spatial changes in land use and land cover. Metal enrichment in the modern Noordhoek wetland sediments and increased organic matter content indicates increasing anthropogenic impacts on the valley as agriculture and urbanisation increased. In comparison. there is a much lower concentration of heavy metals at Groot Rondevlei, as its catchment has been less prone to severe local disturbance such as urban development and recent agricultural activities. The absence of a tightly resolved chronology for these cores restricts the understanding of the commencement and duration of major environmental changes, which have been accounted for elsewhere in the region. This limits the opportunity for direct comparison between this and other known sites. However, the Noordhoek valley is a potential resource for longer-term Quaternary environmental study. The application of a multi-disciplinary approach and high-resolution dating are highly recommended for future research in this area.

Includes bibliographical references (leaves 106-111). / The Breede River catchment in the South Western Cape is already under pressure for its water resources due to its supporting a variety of different land uses. The predominant land use in this catchment is agriculture, which demands the majority of river water for irrigation. The Department of Water Affairs and Forestry are currently investigating the future demand for water from the river, in this respect it is important to know what effect climate change will have on the change in river flow. Self Organising Maps (SOMs) are used to identify changes in the circulation systems contributing to the rainfall of the region and from this the potential change is assessed for the Breede River flow under future climate change. It is assessed that the runoff in the Breede River is expected to change under all the models of ECHAM4, CSIRO and HadAM. The magnitude of this alteration is calculated by using the change in the SOM node frequencies between the present and the future data. This is then subtracted from the present runoff data supplied by DWAF. A source of runoff decrease in the future is agricultural irrigation. The increase in irrigation under climate change is determined by inserting future climate data into an agricultural model. Once the increased amount of water used in irrigation is determined, it is subtracted from the projected future runoff. From this it is determined whether the river will be ecologically sustainable under climate change.

No description available.

Includes abstract. / Includes bibliographical references (p. 119-144). / In the continuing quest to improve climate model predictions to meet the increasing demand for knowledge on the regional effects of global climate change, it is pertinent to increase our understanding of how the underlying processes of climate are represented in the models we use to make these predictions. Concerted efforts in model evaluations and intercomparison have provided numerous insights into various model biases which plague current state-of-the-art regional climate models (RCMs). Model evaluation and assessment is crucial to model development and understanding how physical processes are represented in models is necessary for improving model parameterizations. This thesis explored model transferability as a new approach for systematic process-based intercomparison of RCMs. It investigated an untested transferability hypothesis which states that “for non-monsoon regions experiencing weak synoptic scale forcing, the height of the cloud base is correlated with the daytime surface fluxes”. An initial transferability experiment was conducted over Cabauw, the Netherlands (51.97°N, 4.93°E) to assess the models’ skill in resolving the diurnal and seasonal cycles and to investigate the simulated connections between surface and hydrometeorological variables over a non-monsoon station. The ability of models to resolve these cycles correctly is a good metric of their predictive capabilities. The data used for the study comprises three-hourly surface observations for the period October 2002 – December 2004 from the Coordinated Enhanced Observing Period (CEOP) measuring campaigns of the Global Energy and Water Cycle Experiment (GEWEX) and three-year simulations (2002 -2004) from five RCMs (CLM, GEMLAM, MRCC, RCA3 and RSM). In simulating seasonal and diurnal cycles of CBH and surface variables, the European models (CLM and RCA3) demonstrate a clear home advantage over the North American models (GEMLAM, MRCC and RSM). Principal component analysis revealed that the models couple the cloud base height with surface fluxes as in observations and that this coupling is not sensitive to changes in wind speed. This study found that summer daytime loadings gave the strongest couplings of variables. Three major processes were identified over Cabauw. First and most dominant is the surface energy process which couples sensible and latent heat with net radiation. The second process is thermodynamic, coupling temperature and surface moisture (specific humidity), and the third is a dynamic process which couples pressure and wind speed. A model intercomparison was then carried out across the six midlatitude domains to test the validity of the Cabauw findings. In observations, CBH is well coupled with the surface fluxes over Cabauw, Bondville, Lamont and BERMS, but coupled only with temperature over Lindenberg and Tongyu. All the models (except GEMLAM) simulated a good coupling with surface fluxes at all stations. In GEMLAM, there is no coupling between CBH and surface fluxes at any station. In less homogenous domains of the study, a very slight decrease in the strength of coupling is seen in most of the models, under strong large scale forcing. This would suggest that the coupling between cloud base height and surface fluxes in the models is possibly more influenced by radiative forcing than by synoptic controls. This second study confirmed the findings at Cabauw that the simulated cloud base is correlated with surface energy fluxes and the sign of the correlations in the models is as in observations. This finding is important for the modeling community as it establishes the fact that the models are actually simulating the direction of influence of surface fluxes and possibly, soil water variability, on cloud processes.

Includes abstract. / Includes bibliographical references (p. 226-252). / Fisheries compliance theory has evolved over the past two decades in an attempt to understand the factors that influence fishers’ behaviour and to develop appropriate strategies to enhance compliance. However, much of this research, which draws on both rationalist and normative perspectives, has largely focussed on the industrial fisheries. Empirical research on the small-scale fisheries sector, therefore, has been lacking. The overall aim of this thesis has been to develop a conceptual framework for understanding and addressing small-scale fisheries compliance by drawing on experiences in South Africa. This has been achieved through a detailed investigation of two small-scale fisheries case studies, as well as a review of the small-scale fisheries sector generally. The findings from this research have emphasised the need to rethink ourunderstanding of fisheries compliance in the small-scale sector. By drawing onempirical evidence, as well as the literature review, a conceptual framework has beendeveloped that enhances existing compliance theory. This study highlights that anunderstanding of compliance behaviour first requires a critical analysis of how lawhas evolved, its history and the power dynamics that have shaped it. The conceptualframework further emphasises the need to understand compliance within a fisherysystem, acknowledging that social, economic, institutional and biophysical factors allimpact on whether or not fishers’ comply with rules and laws. By applying theconceptual framework to two case studies in South Africa, key drivers that influencefisher behaviour over time are identified and changes within the fishery system areanalysed and documented. This thesis has also contributed to fisheries compliancetheory by identifying the underlying principles that are seen as necessary to guide an alternative and more integrated approach to small-scale fisheries compliance. In addition to the principles of legitimacy and deterrence, which are incorporated into existing theories of compliance, this study emphasises that the principle of social justice is required to develop a more holistic approach to understanding and addressing small-scale fisheries compliance. By embracing these principles, it is argued that fisheries policies will shift away from a sole reliance on criminal justice to achieve compliance, to a more integrated approach that aims to sustain the fishery system as a whole.

Includes bibliographical references. / Natural sacred sites are areas protected by traditional groups as a point of connection to the land. They are also acknowledged for their disproportionate biodiversity contribution. These natural remnant patches have, however, recently come under threat from surrounding anthropogenic land-uses. This study aims to establish the spatial landscape pattern and associated land-uses surrounding the Venda sacred site of Thathe Forest in north-eastern Limpopo, South Africa, while investigating links to landscape governance. A terrain analysis of the study area is conducted using the thematic layers of geology and soils, gradient, aspect, and hydrology. This analysis is contrasted with a land-cover classification of the study area, further linking results to land-use decision-making.

Cities are increasingly important actors in the current International System. Cities fall under the jurisdiction of States where they play a fundamental role in the making and consolidation of emerging powers. In today’s State-centred International System, cities are underexamined in the field of foreign policy, a domain that is exclusively that of national governments. Using the cases of Colombia (Bogotá) and South Africa (Johannesburg), this thesis draws from multilingual sources to examine the role of cities in the foreign policy of emerging powers of the Global South. An interdisciplinary approach indicates that, by drawing together debates across International Relations and Urban Studies literature, there is little to no place for the conceptual and operational cross pollination necessary to engage the increasing importance of cities in the emerging powers of the Global South. The weak interface between cities and States in foreign policy is thus failing to inform local-national government interactions over global positioning and masks critical national actors in the evolution of cities. Through a geopolitical analysis, this thesis engages the conceptual and operational ambiguity around 'emerging powers’ by demonstrating how at both the national and city scale notions of 'power resources’, 'leadership’ and 'international recognition’ are actualised in the emerging powers of Colombia and South Africa. By tracking the ways that Bogotá and Johannesburg operate internationally, cities are, despite the lack of formal acknowledgement or endorsement of the nations’ foreign affairs machinery, shown to be crucial contributors to their countries’ emergence in the world. An analysis of primary sources in both Colombia and South Africa shows a mismatch between the city and the State in foreign policy caused by dynamics occurring both at national and local levels. The constitutional and legal ambiguities on decentralisation and foreign policy found in Colombia and South Africa make it extremely difficult to determine the how far sub-national entities can go in their burgeoning international engagements. The State-centred approach to foreign policy that is found in both countries contributes greatly to a general disregard for the city in international relations. Finally, the thesis reveals how the increased importance of cities in the global agenda and the proliferation of international associations of cities provides emerging cities such as Bogotá or Johannesburg with an alternative space in which to defend their own city interests without the help of the national governments. The thesis concludes by demonstrating that, while it is important that national governments make sure cities have a voice in the International System, changes also need to be made at the domestic level, both in national and local governments, in order to achieve functioning levels of understanding and co-operation between the city and the State in the making and implementation of the foreign policy of emerging powers.

Includes bibliographical references. / Customary systems of marine resource governance have gained increasing attention internationally in the past three decades. Notwithstanding this, and despite the Constitutional recognition of customary governance and customary law in South Africa, the post-apartheid legislative reforms in the fisheries sector have failed to recognise customary systems of marine resource governance. Drawing on a case-study of the Dwesa-Cwebe community in the Eastern Cape, South Africa, this research aimed to describe and understand the customary marine resource governance system of this community and its relationship to living customary law. It explores how this customary system of marine resource governance has interfaced with statutory and other systems of law in the past and how it continues to develop in the current context. The findings from this research highlight the distinctive nature of the customary system of marine resource governance practiced by the community of Dwesa-Cwebe and their expressions of living customary law embedded in this governance system. The nature of this system is foundationally different to that of a Western statutory governance system. This customary system of governance has interacted with the statutory system for over a century, in part distorted by this system but retaining its integrity. In the context of the Constitutional recognition of customary systems of governance and customary law, this governance system now requires understanding and recognition in a new system of marine resource governance in South Africa. This thesis explores the contribution that this system of customary governance can make towards promoting socially just smallscale fisheries in South Africa. It argues that harmonisation of the statutory and customary system of marine resource governance demands an approach to governance theory and practice that is able to imagine an alternative ‘ecology of governance’.