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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Regional temperature and precipitation trends in the Drakensberg alpine and montane zones: implications for endemic plant species

Marsh, Patricia Beryl January 2017 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the Degree of Masters of Science by Coursework and Research Report. Johannesburg November 2017. / Mountains are complex environments owing to their varying topography and geographic range, and as a result are havens for a variety of eco-systems and biodiversity. Mountain systems around the globe are potentially transforming due to increasing pressure from human-driven climate change. The possible effects of these pressures and overall consequences of the changes are difficult to predict due to the complexity of mountain habitats. Previous studies have recorded increasing temperatures in mountain systems as one of the consequences of climatic change. As a consequence of this warming trend, plant species that typically grow in lower altitudes may migrate to higher altitudes as those habitats become suitable. There are many different effects this may have on the local eco-system, such as the possibility of the migrating species outcompeting the local species or even hybridization occurring, resulting in a new species. Regardless, the movement of species from low to high elevations will have a direct effect on plant community dynamics in the area. South Africa is experiencing warming temperatures and has experienced a reported increase in mean annual temperature by 0.96 ºC over the last five decades. This research aims to understand the implications of inter-annual temperature and precipitation trends in the alpine, upper and lower montane thermal zones in the Drakensberg on two endemic plant genera, Rhodohypoxis (Hypoxidaceae) and Glumicalyx (Scrophulariaceae). A thermal zone refers to a temperature gradient at a specific altitude in a mountain system. Temperature and precipitation data from 1994 to 2014 were collected from four weather stations: Sani Pass (2874 m), Shaleburn (1614 m) and Giants Castle (1759 m) in South Africa, and Mokhotlong (2209 m) in Lesotho. These sites represent three thermal zones; Sani Pass is in the alpine zone, Mokhotlong is in the upper montane zone, and Shaleburn and Giants Castle are in the lower montane zone. The objectives of this research are to analyse and compare the temperature and precipitation trends, inter-annual variability, and annual number of frost days at each data collection site from 1994 to 2014, as well as infer the potential impact these changes may have on the local endemic plant genera. Results show a more pronounced increase in temperature in the lower thermal zones and a larger decrease in precipitation in higher thermal zones. The lower montane zone experienced the highest increase in temperature of up to 0.6 ºC over two decades. The alpine zone showed the largest decrease in precipitation of on average 27.5 mm of rainfall per annum over 20 years, while the lower montane zone displayed the largest inter-annual variability in both temperature and precipitation variables. The upper montane zone had a larger decrease in frost days over the 20 year period relative to the lower montane zone. Interestingly this work showed an increased warming pattern in the lower thermal zones relative to upper zones, which contrasts with work in other mountain ecosystems. This warming may create larger intermediate regions which could encourage the movement of endemic flora into neighbouring thermal zones. Movement between thermal zones may increase hybridization within plant genera which could change the structure of the plant communities and possibly result in altered floral populations. Keywords: Climatic change, Drakensberg, endemic flora, thermal zones, temperature and precipitation trends, inter-annual variability / LG2018
2

A survey of San paintings from the southern Natal Drakensberg

Steynberg, Peter John January 1988 (has links)
From Introduction: The study of San rock art has undergone several different phases in approach to the interpretation of art. Two approaches are currently in use. The first emphasises the art as narrative or literal representations of San life and its proponents may be called the "art for art's sake" school. Adherents to the second approach make detailed use of the San ethnography on the belief system of these people and are highly critical of the literalists because they provide no such context. The second approach has rapidly gained ascendancy and replaced the "art for art's sake" school over the last twenty years. The watershed came with the researches of Vinnicombe (1967) in the southern Drakensberg and Maggs (1967) in the Western Cape who both embarked upon programs of research which had quantification and numerical analysis at their core, so that they could present "...some objective observations on a given sample of rock paintings in a particular area..." in order to compare and contrast paintings from geographically different areas. What Vinnicombe's numerical analyses clearly showed was that the eland was the most frequently depicted antelope and that it must have played a fundamental role "...in both the economy and the rellgious beliefs of the painters...", which opened up the search for what those beliefs might be and how they could be related to the rock art itself. In order to understand what the rock art was all about it was recognised that researchers had to meaningfully contextualise the art within the social and religious framework of the artists themselves. Without the provision of such a relevant context, as many different interpretations of the paintings could be made as there were people with imaginations. Such a piecemeal approach provides a meaningless jumble of subjective fancy which tells us something about the interpreters but nothing about the rock art. It is unfortunate that the advent of this explicitly social and anthropological approach marks the end of the amateur as a serious interpreter of San rock art, for the juxtaposition of the ethnography with the rock art requires a proper training in which the intricacies of symbol and metaphor can be recognised.
3

An evaluation of the periglacial morphology in the high Drakensberg and associated environmental implications.

Grab, Stefan Walter. January 1997 (has links)
Although periglacial research in the high Drakensberg and Lesotho mountains has received growing interest amongst southern African geomorphologists, little detailed, quantitative information was available prior to this study. In an attempt to help overcome this deficit, a quantitative assessment on cryogenic landforms and processes operative in the high Drakensberg was undertaken. Morphological and sedimentological assessments of sorted patterned ground, non-sorted steps, thufur, blockstreams, stone-banked lobes, debris deposits and turf exfoliation landforms were undertaken. In addition, geomorphic process assessments in the field included the measurement of turf retreat at turf exfoliation sites, the determination of frost-heave mechanisms within wetlands and sediment mobilization along the Mashai Stream. Ground temperatures were recorded for thufur from 1993 to 1996. The environmental implications of some of the findings are discussed. Seasonal frost-induced sorted patterned ground emerges annually within a few weeks, demonstrating the effect of regular, diurnal freeze-thaw cycles during the winter months. It is found that the present climate is not conducive to maintaining or preserving miniature periglacial landforms below 3200m a.s.l. during the summer months. Large relict sorted circles, stone-banked lobes and blockstreams are the most conspicuous periglacial landforms in the high Drakensberg and are products of at least seasonally-frozen ground. It is suggested that debris deposits found within high Drakensberg cutbacks are possible indicators for marginal niche and cirque glaciation during the Late Pleistocene. It is demonstrated that in climatically marginal periglacial regions, the microtopographically controlled freezing processes may be of paramount importance in maintaining and modifying the cryogenic landforms that occur. Pronounced temperature differentials are found during the winter months, when thufur are frozen for several weeks and depressions remain predominantly unfrozen. It is suggested that such contemporary temperature differentials induce thermodynamic forces and ultimately ground heave at sites in the high Drakensberg. The pronounced seasonal weather patterns in the high Drakensberg have promoted a cycle of geomorphic process events that operate synergistically and initiate particular erosion landforms. However, cryogenic activity during the colder period is overwhelmed by water induced erosion processes during the summer months in the high Drakensberg. It is concluded that the high Drakensberg is currently a marginal periglacial region, but that periglacial conditions prevailed during both the Pleistocene and some Late Holocene Neoglacial events. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1997.
4

The late quaternary palaeoenvironments of a subalpine wetland in Cathedral Peak, KwaZulu-Natal Drakensberg.

Lodder, Jared. January 2011 (has links)
In contrast to the wealth of palaeoenvironmental research stemming from the eastern Afromontane archipelago, the southern Afromontane component, which comprises largely of the Drakensberg, remains understudied. The Drakensberg constitute an area of significant biodiversity, cultural and economic importance. Suitable sites for palaeoenvironmental research are rare in South Africa due to general arid climatic conditions over much of the country. The KwaZulu-Natal Drakensberg offers a unique opportunity for palaeoenvironmental research through its increased rainfall and higher altitudes, which enable the development of wetlands that have the potential for polliniferous accumulation to occur. Catchment Six in Cathedral Peak is one such wetland that has provided an opportunity to research palaeoenvironmental conditions of the southern Afromontane archipelago component. A 371 cm sediment core was extracted from a subalpine wetland in Catchment Six and analysed using multiple proxies including; pollen, charcoal and geochemistry (carbon and nitrogen stable isotopes). A chronological framework for the core was established based on accelerated mass spectrometry radiocarbon dating of eight bulk sediment samples. A basal date of 15,100 ± 445 cal yr BP was determined at a depth of 298 cm. Poor pollen preservation of the basal portion of the core limited palaeoenvironmental inference for the late Pleistocene section of the record. The multiproxy record provides high chronological resolution for the early to late Holocene. Multi-proxy data indicate that the Holocene period in the Drakensberg was characterised by variable climatic conditions. Charcoal data indicate periods of increased regional fires in the last ca. 400 cal yr BP. Palaeoenvironmental inferences from the Catchment Six record are broadly in agreement with regional climatic indications based on existing literature. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
5

Aspects of the weathering of the Clarens formation in the KwaZulu/Natal Drakensberg : implications for the preservation of indigenous rock art.

Meiklejohn, Keith Ian. 06 October 2014 (has links)
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 1994.
6

Bird community ecology and composition in afrotemperate forests of the Drakensberg Mountains, South Africa.

January 2009 (has links)
Recent research has emphasized the importance of understanding the consequences of species loss, not just for biodiversity per se, but also for ecosystem resilience and functioning. Firstly, a baseline analysis of the effects of a naturally patchy landscape on avian community composition and resilience in a high altitude Afrotemperate forest landscape in South Africa is presented. Bird data from a point count survey of 706 counts at 31 forest sites was used to test whether taxonomic species diversity, functional species richness and density of birds provide insight into community resilience in this historically patchy ecosystem. Bird species richness of forest patches ranged from 17 to 38, with a total species richness of 50. Density was slightly but negatively related to both area and species richness. That density compensation is occurring in these Afrotemperate forests suggests a level of resilience in this system. Following on from this, cumulative species-area and function-area graphs were derived to quantify the loss of forest area or taxonomic bird species richness that this landscape may potentially sustain before ecosystem functioning is negatively affected. The concept that species’ patterns of distribution, abundance and coexistence are the result of local ecological processes has recently been challenged by evidence that regionalscale processes are equally instrumental in shaping local community composition. The historically and naturally fragmented Afrotemperate forests of the uKhahlamba– Drakensberg Park, South Africa, offer an interesting test case. In this study the relative effects of local and regional-scale processes on species assemblages in a naturally patchy forest system were investigated. By employing species-area and species-isolation relationships, and nested subset analyses, we showed that isolation (regional-scale process) had a greater effect on bird species richness and composition than area (local-scale process), though the species-area relationship was significant. Using generalized linear models and an information-theoretic approach to model selection, patch area, the size of the regional species pool as well as the distance to the nearest Eastern Mistbelt forest were all influential in determining local bird species richness in these montane forests. Thus, localities are regionally enriched within the constraints on species occupancy provided by the available habitat. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
7

Seedling establishment of Themeda triandra Forssk. in the montane grasslands of Natal.

Everson, Theresa Mary. January 1994 (has links)
Soil erosion and vegetation destruction have reached serious proportions in disturbed areas of the montane grasslands of the Natal Drakensberg. Little is known of the inherent ability of indigenous grasses to produce viable seed and establish seedlings for rehabilitation programmes. This study examined the effects of fire and small-scale disturbance on the seedling dynamics of the dominant grass, Themeda triandra Forssk. Annual seed production of T. triandra increased with length of burning rotation, ranging from 21 seeds m⁻² in the annual winter burn to 485 seeds m⁻² in the five-year burn. High predation of seeds (70-98%) and low viability (37% in 15 month-old seeds) contributed to the poor representation of T. triandra in the seed bank when compared to the aboveground vegetation. Seedling densities and survival were monitored by mapping quadrats at six-weekly intervals from November 1986 to September 1989. Highest establishment of T. triandra was recorded in the biennial spring burn treatment (< 184 seedlings m⁻²). Microclimatic studies of the seedling environment demonstrated that increases in photosynthetically active radiation following burning, and high soil moisture associated with accumulation of litter, favour seedling establishment. The main constraint to seedling establishment was high mortality in winter which resulted in a 1% survival of seedlings of T. triandra during the three-year study. This indicates that in the fire-climax grasslands of the study, seedlings contribute little to the population structure. The most significant factor contributing to low survivorship is intraspecific competition between seedlings. Spacing of seedlings in rehabilitation programmes is therefore a critical factor in optimizing seedling establishment. Analysis of the fate of seeds of T. triandra between their production and establishment, showed that the main constraints for seedling establishment were predation, low viability and poor germination. A population model, based on transitions between seeds, seedlings and mature tufts, predicts that a biennial spring burn is the optimal treatment for maximising both seedling establishment and vegetative growth. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.
8

On the climate of the Drakensberg rainfall and surface-temperature attributes, and associated geomorphic effects /

Nel, Werner. January 2007 (has links)
Thesis (D.Phil.(Geography))-University of Pretoria, 2007. / Includes summary. Includes bibliographic references (leaves 185-188).
9

A Hydrological-slope stability model for shallow landslide prediction in the Injisuthi Valley, KwaZulu-Natal Drakensberg

Bijker, Hermina Johanna 24 November 2005 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / Unrestricted
10

[Trophic Cascade]: an ecological research, education and information community centre in the Amazizi Tribal Authority of the Drakenburg

Marchant, Craig Galen January 2016 (has links)
This document is submitted in partial fulfilment for the degree: Masters of Architecture [Professional] at the University of the Witwatersrand, Johannesburg, 2015 / The focus of architecture in South Africa is often centered on intense urban areas in the country. However, important though these areas are, they represent only one facet of the greater country. The rural areas around South Africa are repeatedly overlooked. Added to that, our rich heritage and increasingly unique and threatened relationship with the natural systems around us is often sidelined. Our relationship with the natural world is a complicated one. Humans, perhaps the only species on earth able to do so, have the opportunity to decide whether to live symbiotically with nature or parasitically. Unfortunately the choice is often the latter. One of the areas where our rather strained and openended relationship with the natural world is most apparent is in the impoverished rural Bonjaneni Community of the Amazizi Tribal Authority located in the Okhahlamba District of KwaZulu-Natal, South Africa. Mankind’s negative impacts on this regions natural mechanisms are being felt locally and nationally in three particular areas that form the key points of focus for the thesis: grasslands, water systems and the decline of the Cape Vulture population. Grassland is of utmost importance ecologically, economically and socially for the region, without healthy grassland community livestock cannot survive, thatch cannot be gathered and the landscape will become prone to severe erosion during the rainy season. Erosion negatively affects the Tugela River water catchment basin too. Without healthy vegetation cover the landscape and community will become prone to flooding. Silt from the erosion will impact numerous dams further downstream that supply water to KwaZulu-Natal and the economic heartland of South Africa, Gauteng. The repercussions of a threatened population of Cape Vultures are also of concern. Without the specialised scavenger animal corpses will be left to fester in the sun, developing carrion borne diseases that can negatively affect the health of pets, people and livestock. These problems result in a considerable financial burden to the community and the government, yet these are all problems that can be addressed through responsible stewardship of the land and an awareness of our position in the natural world. / EM2017

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