Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / Unrestricted

The Drakensberg range is the highest landscape zone in southern Africa, is a World Heritage site and an important source of surface runoff. General climatic evaluations covering the area, however, date from the 1970’s. Remarkably, few contemporary studies detail rainfall attributes and limited surface-climate data has been collected describing the sub-periglacial summit regions. This thesis presents an evaluation of rainfall and surface-temperature attributes in the mountains and, where possible, related geomorphic implications are described. The assessment is partly based on analysis of historical rainfall data measured by the South African Weather Services during the 20thCentury, and partly on new rainfall, air and soil temperature data collected by the author over a five year period. Historical rainfall records show, when a spatial approach is taken, that altitude and distance from the escarpment eastward influence annual rainfall totals. Latitude plays no significant role in influencing rainfall totals, but is the single important factor influencing inter- and intra-annual rainfall variability. Rainfall variability increases from the southern Drakensberg to the north where important water transfer schemes operate. When a temporal approach is taken, historical records indicate no change in mean annual rainfall during the last half of the 20th century. Intra-annual rainfall variability has increased and this is illustrated by a statistically significant decrease of rainfall during the autumn season. A contemporaneous as well as a lagged correlation exists between the El Niño/Southern Oscillation and summer rainfall in the Drakensberg. An increase in the frequency and intensity of ENSO should decrease summer rainfall and the lagged correlation could be used for summer rainfall forecasting. Using temporary field stations, analysis of rainfall and air, soil and rock temperatures contribute to an improved understanding of the characteristics and structure of rainfall events, surface conditions and effect on rock weathering and soil erosional processes. With respect to rainfall attributes, totals recorded on the escarpment summit are considerably less than anticipated. Individual erosive storm events at all altitudes are found to have the ability to detach soil, but at high altitude less rain falls as erosive storms, and the total erosivity generated by rainfall events is less on the escarpment than in the foothills. Five-minute intensity data indicate that extreme rainfall events generate peak rainfall intensity, within the first half of the storm duration. Mean annual air temperature (MAAT) measured on the escarpment falls within the range previously estimated, but is higher than the MAAT suggested by other authors for the plateau peaks behind the escarpment. No long-duration, or seasonal freeze was found on the soil surface and soil temperatures are generally higher than air temperatures. Rock temperature and rainfall frequency recorded below the escarpment imply an environment conducive to rock weathering processes such as wetting and drying and thermal fatigue with the possibility of frost action. Contrasting air, rock and soil surface temperatures measured in the Drakensberg, emphasises the dissimilarity in micro-environmental conditions experienced by different natural mediums in the landscape. Overall, the data confirm the marginal-periglacial nature of the summit region but earlier estimates for rainfall totals at the escarpment appear to be notably high. Extrapolation towards, for example, palaeo-precipitation scenarios using earlier estimates, should thus be made with caution. / Thesis (PhD)--University of Pretoria, 2008. / Geography, Geoinformatics and Meteorology / PhD / Unrestricted

Mariepskop (direct translation: “Marieps hill”) forms part of the northernmost edge of the Drakensberg Mountain range in the east of South Africa, and is known for its complex topography associated with meso-scale atmospheric circulation, and therefore its numerous climatic zones. As a result the mountain hosts a high degree of biodiversity. The peak of Mariepskop lies at approximately 1900m Above Mean Sea Level (AMSL), which is higher than the surrounding escarpment to the east bordering the Highveld. Its foothills also extend well into the Lowveld at about 700m AMSL. Mariepskop is therefore ideal for studying airflow exchange between the industrialized Highveld and the Lowveld with its diversity of natural resources. It is also ideal for detecting global warming signals on altitudinal gradients extending from the Lowveld to altitudes above the Highveld escarpment. In this study, long-term National Centre for Atmospheric Research / National Centre for Environmental Prediction (NCAR/NCEP) reanalysis wind data at two atmospheric pressure levels (850hPa and 700hPa), as well as reanalysis near-surface temperature data, were obtained for the Mariepskop region for the austral summer (and winter) seasons. The data was used to force a Computational Fluid Dynamics (CFD) model (also known as STAR-CCM+) across its lateral boundaries with the dominant synoptic flow in order to generate mesoscale simulation output over the complex terrain of Mariepskop. Wind speed and direction modelled results were then correlated to observations measured by three weather stations on Mariepskop. Modelled wind flow results for the summer simulation were also validated against aerial photographs in order to infer whether the model could accurately capture areas with high rainfall, which are related to denser vegetation. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Geography, Geoinformatics and Meteorology / unrestricted

South African grasslands are under-conserved and there is a need to expand conservation efforts beyond the boundaries of protected areas. While communal grasslands have conservation potential they are generally over-utilized and the impact of communal land-use on biodiversity is poorly studied. At the same time there is pressure on protected areas to allow for the sustainable utilization of biodiversity. The aim of this study was to examine the impact of communal land-use on various components of biodiversity and to make recommendations regarding communal use of protected areas. A fence-line study was conducted to assess the impact of eight years of controlled communal land-use on biodiversity in the uKhahlamba-Drakensberg Park. The communally used land (referred to as the lease land) which was used for controlled grazing as well as plant collection was compared with land under formal conservation. Vegetation was sampled using the importance score method and veld condition assessments. Selected invertebrate taxa were sampled using sweep netting, colour pan traps and transects and were identified to morphospecies level. Multivariate statistics revealed that sites generally grouped according to landscape position rather than land-use. No significant differences were found in diversity, evenness, richness or veld condition between the lease and conservation land. However, more than twenty-five percent of vegetation and invertebrate species were found exclusively in the lease or conservation land, suggesting that different suites of species were supported by the two landuses. Four alien plant species were found exclusively in the lease land, while one vulnerable and one rare plant species were found only in the conservation land. Further research is required to assess whether biodiversity was diminished by controlled communal. While the lease concept may offer potential as a low-use buffer zone, localised damage from cattle paths and weak enforcement of grazing agreements were areas of concern. Keywords: communal grass)ands, grassland flora, grassland invertebrates, transfrontier park. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.