Doctoral Degrees (Geography)

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Natal : a study in colonial land settlement.
(1969) Christopher, Anthony John.; Davies, Ronald John.
No abstract available.
Local atmospheric circulations and the mesoclimate of Durban.
(1970) Preston-Whyte, Robert Arthur.; Davies, Ronald John.
Rapid urban and industrial growth along the Natal coast has occurred with little concern for characteristics of local climate. In general, industrial growth has taken place without taking into account the potential for pollution transportation during the winter season; urban areas have developed without consideration for the vital need in sub-tropical latitudes to maintain adequate mixing of the lower atmosphere. The apparent inadequacy in planning for climate has partly been due to a lack of understanding of the nature and characteristics of local wind systems. The motivation for this study stems , therefore, from the need to evaluate the influence of land-sea and topographically-induced wind systems upon certain aspects of weather and climate on the Natal coast. During summer, moist and relatively cool air is advected almost daily over the Natal coast by the sea breeze . Observations of spatial and temporal variations of these winds were made in the period 1963-69 from recording stations in the Durban area and along a 40-mile transect approximately normal to the coast at Durban. Comparable observations have not as yet been made in South Africa nor have there been a ttempts to examine the influence of sea breezes upon selected climate and weather phenomenon. In this latter connection the role of the sea br eeze is examined in two separate fields in this study, namely urban climatology and thunderstorm development. Climatic discomfort caused by the combined effect of high temperatures and humidities on the Natal coast, is at a maximum in urban areas . Since these areas are also highly populated , a need exists to evaluate the ability of the sea breeze to reduce urban temperatures by advection of cooler air over the area, by eddy diffusion of heat or by displacement of urban temperatures aw~ from poorly ventilated areas. Thus climatic discomfort in these areas may also be reduced. Detailed observations of the influence of the sea breeze, in particular, and wind in general, upon the spatial variation of temperature , humidity and human comfort were, therefore, undertaken in the Durban area. It is believed that this i s the first time an attempt has been made to describe the spatial distribution of a comfort index in an urban area. The results should be of interest to the a rchitect and town planner. The sea breeze, strengthened by gradient and valley Vlinds, is shown to penetrate at least 40 miles inland. In accordance with this , it is suggested that the inland invasion of marine air takes place in response to lowered pressure in adjacent inland areas in southern Natal and provides the moisture required to feed thunderstorms which develop in this area. These storms subsequently move towards the coast following the retreating convergence zone between winds with an onshore and offshore component of motion and reach Durban after sunset. Land breezes are best developed in winter. Observational techniques were similar to those employed in the sea breeze study and provide the only detailed examination of spatial and temporal variations of land breezes in South Africa. Until recently the nature and characteristics of topographically-induced winds in Natal were also a relatively unexplored feature of local atmospheric circulations. However, Tyson (1967) has examined local winds in certain Natal valleys and his prediction that mountain- plain winds reach the coast during the night is also examined in this study. While the relatively weak. and shallow land breeze may be of secondary importance when compared with the sea breeze, it would be a mistake to underestimate the importance of these winds upon certain aspects of coastal climate. In p~rticular the tendency for land breezes to initiate cloud and precipitation at night is examined while the potential for the transportation of atmospheric pollution by these winds is also briefly discussed. A study of the diurnal variation of precipitation at Durban reveals a high frequency of low intensi~ precipitation at night. The nature of this precipitation differs in both frequency and" amount from high intensity rainfall which is the product of thunderstorm and frontal activity. It is suggested in this study that the land breeze plays a dominant role in providing the buoyancy necessary to cause nocturnal drizzle precipitation from shallow stratus cloud. The thesis is divided into four parts. Part I examines details of the physiography, weather, climate, observati ~nal methods and analysis techniques. Because of the variability of weather on the coast of Natal that section is dealt with in more detail than would have been deemed necessary for a similar study inland. Without knowledge of the characteristics of the atmospheric circulation, the behaviour of local wind systems in relation to large scale systems could not be adequately discussed. In Part II land and sea breezes and topographically-induced wind systems are examined in detail. Emphasis is placed not only on the observational characteristics of these winds such as onset, depth, velocity gradient, surging, relation to gradient winds and dissipation but also on their relation to theoretical models of the relevant wind system. The influence of local wind systems upon selected climatic elements is dealt with in Part Ill. Characteristics of the diurnal variation of precipitation are examined in Chapter 6. Rainfall frequencies and amounts are shown to be highest in the first half of the night and a model is developed to explain the influence of land breezes and mountain-plain winds upon low intensity but high frequency nocturnal rainfall. High intensity but low frequency rainfall produced by thunderstorms also occurs soon after sunset and a further model is advanced to explain this phenomenon in relation to the sea breeze. The effect of air movement upon the spatial variation of temperature, humidity and a discomfort index in both summer and winter is examined in Chapters 7 and 8. The relationship between these elements has permitted the development of an empirical model to predict values across the city of mean midday summer and winter temperatures as well as discomfort index values. In Part IV the most significant aspeots relating to the study as a whole are summarised. In conclusion the potential f or the transport of pollutants by land breezes and topographically induced winds is briefly discussed as an aid to planning and siaple spatial models are given showing generalised air movement and ventilation characteristics in the Durban area and along the Natal coast.
A comparative study of soil erosion in the Umfolozi Game Reserve and adjacent Kwazulu area from 1937 to 1983.
(1990) Watson, Helen Kerr.; De Villiers, G du T.
This thesis describes a comparative study of actual and potential soil erosion in the Wilderness area of the Umfolozi Game Reserve, and a biophysiographically comparable adjacent traditional KwaZulu landuse area. Estimates of temporal and spatial variations in eroded surfaces, sparsely vegetated surfaces susceptible to erosion, and active gullies were obtained from five sets of sequential aerial photographs taken between 1937 and 1983. Estimates of the potential influence of rainfall erosivity, soil erodibility, topography, and changes in vegetation communities and landuse practices on these variations, were extrapolated from these aerial photographs as well as from maps, field surveys, records and other studies. Interrelationships between these potential influences, and the extent to which they actually contributed to the temporal and spatial variations in the three 'erosion' surfaces, were assessed visually using a geographic information systems thematic overlay technique, and computationally using a forward stepwise multiple regression procedure.
The Group Areas Act in Durban : central-local state relations.
(1992) Maharaj, Bridgemohan.; McCarthy, Jeffrey J.
Aspects of the weathering of the Clarens formation in the KwaZulu/Natal Drakensberg : implications for the preservation of indigenous rock art.
(1994) Meiklejohn, Keith Ian.; Hall, Kevin John.
Communal space construction : the rise and fall of Clairwood and district.
(1994) Scott, Dianne.; McCarthy, Jeffrey J.
This study documents the emergence of an Indian cultural enclave located on the periphery of the colonial town of Durban, its subsequent rise to a flourishing communal space by the mid twentieth century, and its decline in the apartheid era. The focus on change and transformation locates the research question within the broad ambit of historical geography. Clairwood and District grew into a densely-populated informal living space with all facilities and institutions built by the community. Based on a cultural inheritance in the form of language, the extended family system and religious beliefs , the Indian settlers and their descendants developed an elaborate network of kinship and communal relationships which formed the moral and social framework for the process of communal space construction. Entering the colony of Natal predominantly as indentured labour, the Indians were from the outset ostracized and subjugated by the white settlers and perceived as an alien temporary group. This identity was henceforth embodied in discriminatory legislation which marginalized the Indians in South Africa and resulted in their neglect and spatial containment. Parallel to the organic process of Indian communal space construction occurring in southern Durban was the sustained policy of land-use transformation embarked upon by the Durban municipality. The goal of this policy was to create a 'productive zone' south of Durban within an explicit racial zoning plan. The application of this goal resulted in a clash between the dominant white culture and the subordinate Indian culture as each.sought to retain control of the southern corridor and define its land-use and identity. After a protracted struggle the Durban municipality succeeded in imposing a formal industrial landscape upon the communal living space with the exception of the small node in Clairwood itself which has remained a residential enclave. This vestige of the former flourishing residential area of Clairwood and District suffers from industrial penetration and a physically degraded environment. However, it retains a sense of place of the former vibrant community. Clairwood is currently undergoing a process of revitalization under the auspices of the Durban municipality with a subsequent redefinition of identity. The study documents the cultural meanings that have been produced in a unique urban landscape in a South African city revealing the need to uncover the historical geographies of minority groups as a source of identity and a resource for future urban reconstruction.
Rethinking society and space : neighbourhood, locality and region in a changing South Africa.
(1994) Wittenberg, Martin Werner.; McCarthy, Jeffrey J.
Abstract available in pdf file.
The development potential and impacts of commercial eucalyptus woodlots in selected areas of KwaZulu, South Africa.
(1994) Cellier, Guy Anthony.; Slade, D. Graeme B.; Roberts, Peter J. T.
This thesis is an analysis of the social, economic and ecological impacts of commercial Eucalyptus woodlots beign promoted by a private timber company in certain parts of northern KwaZulu, South Africa. The impacts are considered from the perspective of the rural farmers themselves via a qualitative methodology consisting of semi-structured, in-depth individual interviews and focus group discussions. The results of the study show that these woodlots would offer only supplementary income to the majority of the growers. There is little opportunity cost in terms of land or labour, and ecological impacts can be minimised through a programme of education and responsibility on behalf of the company. However, the growers involved feel alienated from the whole tree-growing process occurring on their land. The potential for rural development and empowerment does exist, but will require a fundamental paradigm shift and long-term commitment on the part of the company promoting the woodlots. Commercial woodlots have an important role to play in the 'new' South Africa by showing that the aspirations of the rural poor need not be compatible with the profit-orientated motives of private companies. A model is proposed which consists of training, strengthening existing institutional structures, and initiating ongoing, on-farm research. Following such a model would allow commercial woodlots to form part of an appropriate social forestry land-use system for the region.
Ozone maxima over Southern Africa : characteristics and mechanisms.
(1995) Combrink, Jane.; Diab, Roseanne Denise.
This thesis aims to clarify the sources of, and mechanisms associated with, the generation of ozone maxima over the southern African region. Inasmuch as, tropospheric ozone concentration is a function of both chemistry and meteorology, this thesis concentrates on the role of atmospheric dynamics. Firstly, a statistical analysis of the relationship between total ozone and meteorological parameters revealed a generally weak negative relationship between total ozone and the height of the 500, 300 and 100 hPa geopotential surfaces. The relationship is best expressed by the passage of a mid-latitude cyclone while anticyclonic conditions exhibited a weak relationship. An examination of the spatial distribution of total ozone and potential vorticity (PV), during the passage of westerly troughs, prompted a more thorough investigation of the exchange of ozone between the stratosphere and troposphere. The relationship between tropospheric ozone, and low pressure and anticyclonic systems is investigated further using data obtained during the South African Fire-Atmospheric Research Initiative (SAFARI) conducted in 1992. Ozone concentrations, as expressed by ozonesonde data, reveal different characteristic profiles for the two scenarios. Explanations for the differences observed are sought in the observed circulation patterns during the experiment. Case studies at Okaukuejo (Namibia), Irene (South Africa) and Brazzaville (Congo), which were utilised as ground stations during SAFARI, are presented in an attempt to gain insight into the vertical distribution of ozone over the entire expanse of the study region. The role of convective systems in the generation of short-lived upper tropospheric ozone maxima at tropical latitudes is illustrated while the different vertical ozone signatures, expressed under cyclonic and anticyclonic systems as described earlier, are reconfirmed by the Okaukuejo and Irene data. An attempt is made to investigate dynamic links between the troposphere and stratosphere and the concomitant exchange of ozone during the passage of westerly trough systems. Particularly deep troughs or cut off low pressure systems are identified as important mechanisms in the generation of upper tropospheric ozone maxima. An examination of the vertical distribution of ozone at Irene during the passage of a COL, using data obtained from the SA'ARI 1994 experiment, suggests concurrence with Danielsen's (1968) model of tropopause folding. The intrusion of high PV and dry stratospheric air, coupled with downward flow near the tropopause, in the vicinity of the upper tropospheric disturbance, promotes the transport of ozone-rich air to tropospheric altitudes. The limited availability of data has severely hampered the understanding of tropospheric ozo~e in southern Africa in the past. This study demonstrates the value of daily vertical ozone data, even for very short periods.
Subsurface soil erosion phenomena in Transkei and southern KwaZulu- Natal, South Africa.
(1996) Beckedahl, Heinrich Reinhard.; Fincham, Robert John.
Subsurface erosion forms has been regarded as a unique exception to the more common surficial erosion forms such as rills and gullies, and have therefore been viewed as being of little consequence consequence for the total annual soil loss within any given region. A total of 148 subsurface erosion system occurring at 66 sites in Southern KwaZulu-Natal and Transkei were analysed morphologically to determine the significance of subsurface erosion within this region, to assess the extent to which the observed phenomena may be explained by current theories. Based on morphological criteria related to the dimensions of the subsurface erosion phenomena, it has been shown that there are five distinct -subsurface erosion systems namely scree slope systems; gully- sidewall systems; anthropogenically induced systems; system associated dispersive soils, seepage systems. It was further found that, under certain circumstances, the sediment lost through surficial erosion can be increased 77% by subsurface erosion and the subsurface erosion is spacially to particular slope units which are defined on the basis of the dominant geomorphic processes. Although soil chemistry, in particular dispersion related to the exchangeable Sodium percentage and the Sodium Absorption Ratio, is an important factor in facilitating subsurface erosion, other factors are also important as scree slope systems for example occur in soils which are completely non-dispersive. It has been possible to demonstrate that there is a statistically' significant correspondence between the spatial orientation of inter-ped surfaces the orientation of bedrock joints. This correspondence has enabled the explanation of how the well documented phenomenon of structurally controlled drainage basins may develop._ This correspondence has enabled the explanation of how well documented phenomenon of structurally controlled drainage basins may develop.
An evaluation of the periglacial morphology in the high Drakensberg and associated environmental implications.
(1997) Grab, Stefan Walter.; Hall, Kevin John.; Ahmed, Fethi B.
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.
The meaning and expression of tourism among urban blacks : a geographic perspective.
(1999) Mkhize, Isidore Bandile.; Butler-Adam, Joann Camille Ellis.; Soni, Dhirajlal Vallabh.
This study was designed to investigate the meaning of the concept of tourism among black South Africans in general and black urban dwellers in particular. The aims of the study were as follows: (a) To look at how black urban dwellers engage in tourist activities. (b) To look at what black urban dwellers understand by the concept of tourism. (c) To find out what places and tourist destinations black people prefer to patronise. (d) To establish the distances black people travel to reach tourist destinations. (e) To focus on the quality of the experiences black people gain at tourist destinations. (f) To gain knowledge about the modes of transport black people use to reach tourist destinations. The dimensions, which pertain to the expression of tourism, were connected. This connection was done in such a way as to reflect on those features of tourism experience which are common amongst urban blacks, and those, which differ for a variety of social and economic reasons. The data presented and analysed in this investigation was gathered from two sources. Quantitative data was collected from a sample of 580 urban black dwellers from several black townships. Qualitative data was collected from 30 families who reside at Esikhawini township. The principal hypothesis of the study is that tourism is not popular among black South Africans mainly because of economic constraints, and a legacy of discriminatory legislation, discriminatory attitudes, as well as the unattractiveness to black tourists of tourist destinations. The sub-hypotheses are as follows: (a) Blacks prefer to visit places where they can be accommodated by friends and relatives. (b) Blacks regard visits to friends and relatives who stay long distances from them as part of tourism. (c) Black people's experience of tourism is more regional than national. (d) Black people prefer to visit urban destinations than rural areas. (e) There are clearly identifiable dimensions of black people's participation in tourism and tourist experience which are common amongst urban blacks. The most important conclusions of the study are: (a) Black urban dwellers understand tourism to mean the practice of travelling for recreation. (b) Black urban dwellers prefer to visit destinations where they can be accommodated by friends and relatives. (c) Black urban dwellers' experience of tourism is more regional than national. (d) Black urban dwellers are mostly attracted to urban destinations than rural areas. (e) Black urban dwellers' tourist experiences have been grossly affected by the policy of apartheid which prohibited them from visiting certain destinations and deprived them of disposable income. The study sheds light on the perceptions and involvement of black urban dwellers in tourism. The investigation of the meaning and expression of tourism among urban blacks is a valuable exercise if tourism is to be made accessible to all South Africans regardless of race, colour and creed. Key words: Tourism, Tourist, Urban Black, Tourist Attraction, Tourism Experience, Tourism Destination.
Management and regulation of rural land use : a model for traditional land tenure systems in KwaZulu-Natal.
(2000) Montgomery, Andrew David.; Slade, D. Graeme B.
South Africa is confronted by a number ofproblems which include: a high and rapidly increasing population, conditions of poverty, hunger, illiteracy, unemployment, and a degrade9 environment. These problems are associated with inappropriate land use and development and the unwise utilization of natural resources. This work investigates the rural land use dynamic within KwaZulu-Natal and specifically where many of these conditions are most evident, namely: within traditional land tenure areas. The need for an effective, transparent, measurement-based and environmentally linked land use management and regulation system is investigated and a theoretical model is developed with sustainable development as the central focus. The proposed methodology modifies South African approaches to land use management and regulation and draws on the rationale employed within intemationalland use management and state ofthe environment research. The model has the following aims: to strive towards the collective achievement of sustainability as the underlying goal within the planning and plan implementation process; to develop the capability of measuring the extent to which planning policies, goals and programmes are achieved; to guide their review and reformulation; to encourage the inclusion and integration of the policies and programmes of all public and private agencies; and thereby to strengthen the link between land use planning and land use management. The implementation of this model entails an iterative process of performance indicator identification, selection, application and evaluation with full stakeholder participation. The findings suggest that: the sensitive and gradual application of this system is likely to guide land use towards sustainability, initially by non-statutory means. Later, as stakeholder knowledge and understanding increases, this system has the potential to fulfil a valuable statutory function. It is proposed that the practical application of this theoretical approach will facilitate the accurate evaluation and review of policy, plans and programmes during implementation, which will enhance the management and regulation of rural land use towards sustainability within the context of the social, economic and biophysical environment.
A model of communities' perception of municipal service delivery in South Africa with particular reference to Pietermaritzburg.
(2000) Dalton, David Robert.
Abstract available in PDF.
The geography of health in the Durban Metropolitan Area.
(2002) Moodley, Vadivelu.; Soni, Dhirajlal Vallabh.
In presenting a Geography of Health of the Durban Metropolitan Area, the researcher has chosen a conceptual framework within which to sharply challenge the definition of health in a perfunctory/ functionalist way. Thus, the Geography of Health is, at the outset, locationally positioned in a socio-economic and environmental context of society. This argument is developed through a multi-conceptual approach that leads the thesis into building a framework with the central arching principles of biomedicine, social and humanistic philosophy in three randomly selected informal settlement contexts. The specific focus of this approach is on the growing poverty and homelessness, the inadequate health delivery system and the relationship between disease, physical, social and residential environments and structural inequalities. Thus, this study is embedded in numerous related contexts, the most important of which is the spatial! geographical and the social context in which health and health care is seen in relation to the nature of society and everyday life. To some extent this research endeavour is concerned with health and health care issues amongst specific categories of people within marginalized communities rather than some homogenous, non-existent category called "poor people". The key questions raised in the study relate thus to several variables that impact informal dwellers with the specific objective of determining socio-economic profiles, housing and environmental circumstances; the location and nature of health services; health status of people; the ways in which people conceptualise and prioritise health and the need for and possibility of community involvement in health and health care. In dealing with the above issues, a multi-faceted methodological approach allowed for the generation of 155 tabulations from the quantitative empirical data to be triangulated with the qualitative data produced through focus group interviews and also with the secondary data obtained. The most significant finding emerging from the study was the fact that the relationship between health and abject poverty is bi-directional. Respondents identified numerous factors that affected their health, the most important of which was poverty in respect of poor dwellings, lack of basic services, access to certain health services and the prevalence of disease. It is hardly surprising that a biomedical perspective largely prefaced the respondent's understanding of health. This can be attributed to locational factors but more specifically to the overriding socialising influence of biomedicine in South African society. In the focus group interviews with informal dwellers, the ranking exercises demonstrated that high health risks emerge from multiple and complex factors related to personal, economic, social, environmental and political factors. It is the contention of this thesis that health status improvement and the reduction of health risks of disadvantaged individuals and communities needs a multi-pronged approach with multiple solutions drawing on resources from international, national and local agencies and organisations. Finally, the study concludes by presenting an extensive pool of more concrete systematic and holistic interventions that would not only improve the quality of public health care, but also redefine the Geography of Health in South Africa. These, it is argued are seldom attainable in the short term as it is a continuous process underpinned by priorities, possibilities and planning.
Mechanical weathering in cold regions with special emphasis on the Antarctic environment and the freeze-thaw mechanism in particular.
(2003) Hall, Kevin John.
Consideration of almost any geomorphology textbook will show the fundamental argument that in cold environments mechanical weathering processes, usually freeze-thaw, will predominate and that chemical weathering will be temperature-limited, often to the point of non occurrence. These basic concepts have underpinned geomorphology for over a century and are the basis for the development of many landforms in periglacial regions. With the introduction of data loggers so field data became more readily available but, sadly, those data were not of a quality to other than justify the existent assumptions and thus did little more than reinforce, rather than test, the nature of our understanding of cold region weathering. Factors such as rock properties were dealt with to a limited extent but rock moisture was all but ignored, despite its centrality to most weathering processes. Here the results of field studies into weathering in cold regions, coupled with laboratory experiments based on the field data, are presented. An attempt is made to overcome the shortcomings of earlier studies. Temperature, moisture and rock properties have all been considered. Processes were not assumed but rather the data were used to evaluate what processes were operative. The results, both in terms of weathering process understanding per se and of its application to landform development, significantly challenge our longheld perceptions. Information is presented that shows that it is not temperature, but rather water, that is the limiting factor in cold region weathering. Indeed, in the absence of water, many cold environments have attributes akin to a hot desert. The relevance of this is that weathering processes other than freeze-thaw may play a significant role and that in the presence of water chemical weathering can play a far greater role than hitherto thought. Overall, the whole concept of zonality with respect to weathering is questioned. Finally, the attributes of weathering are put within the context of landform development and questions raised regarding the origin of some forms and of their palaeoenvironmental significance. Attributes of periglacial, glacial and zoogeomorphic processes and landforms in present and past cold environments are also presented.
An investigation into using textural analysis and change detection techniques on medium and high spatial resolution imagery for monitoring plantation forestry operations.
(2006) Norris-Rogers, Mark.; Van Aardt, Jan.; Ahmed, Fethi B.; Coppin, P. R.
Plantation forestry involves the management of man-made industrial forests for the purpose of producing raw materials for the pulp and paper, saw milling and other related wood products industries. Management of these forests is based on the cycle of planting, tending and felling of forest stands such that a sustainable operation is maintained. The monitoring and reporting of these forestry operations is critical to the successful management of the forestry industry. The aim of this study was to test whether the forestry operations of clear-felling, re-establishment and weed control could be qualitatively and quantitatively monitored through the application of classification and change detection techniques to multi-temporal medium (15-30 m) and a combination of textural analysis and change detection techniques on high resolution (0.6-2.4 m) satellite imagery. For the medium resolution imagery, four Landsat 7 multi-spectral images covering the period from March 2002 to April 2003 were obtained over the midlands of KwaZulu-Natal, South Africa, and a supervised classification, based on the Maximum Likelihood classifier, as well as two unsupervised classification routines were applied to each of these images. The supervised classification routine used 12 classes identified from ground-truthing data, while the unsupervised classification was done using 10 and 4 classes. NDVI was also calculated and used to estimate vegetation status. Three change detection techniques were applied to the unsupervised classification images, in order to determine where clear-felling, planting and weed control operations had occurred. An Assisted "Classified" Image change detection technique was applied to the Ten-Class Unsupervised Classification images, while an Assisted "Quantified Classified" change detection technique was applied to the Four-Class Unsupervised Classification images. An Image differencing technique was applied to the NDVI images. For the high resolution imagery, a series of QuickBird images of a plantation forestry site were used and a combination of textural analysis and change detection techniques was tested to quantify weed development in replanted forest stands less than 24 months old. This was achieved by doing an unsupervised classification on the multi-spectral bands, and an edge-enhancement on the panchromatic band. Both the resultant datasets were then vectorised, unioned and a matrix derived to determine areas of high weed. It was found that clear-felling operations could be identified with accuracy in excess of 95%. However, using medium resolution imagery, newly planted areas and the weed status of forest stands were not definitively identified as the spatial resolution was too coarse to separate weed growth from tree stands. Planted stands younger than one year tended to be classified in the same class as bare ground or ground covered with dead branches and leaves, even if weeds were present. Stands older than one year tended to be classified together in the same class as weedy stands, even where weeds were not present. The NDVI results indicated that further research into this aspect could provide more useful information regarding the identification of weed status in forest stands. Using the multi-spectral bands of the high resolution imagery it was possible to identify areas of strong vegetation, while crop rows were identifiable on the panchromatic band. By combining these two attributes, areas of high weed growth could be identified. By applying a post-classification change detection technique on the high weed growth classes, it was possible to identify and quantify areas of weed increase or decrease between consecutive images. A theoretical canopy model was also derived to test whether it could identify thresholds from which weed infestations could be determined. The conclusions of this study indicated that medium resolution imagery was successful in accurately identifying clear-felled stands, but the high resolution imagery was required to identify replanted stands, and the weed status of those stands. However, in addition to identifying the status of these stands, it was also possible to quantify the level of weed infestation. Only wattle (Acacia mearnsii) stands were tested in this manner but it was recommended that in addition to applying these procedures to wattle stands, they also are tested in Eucalyptus and Pinus stands. The combination of textural analysis on the panchromatic band and classification of multi-spectral bands was found to be a suitable process to achieve the aims of this study, and as such were recommended as standard procedures that could be applied in an operational plantation forest monitoring environment.
The role of tourism in natural resource management in the Okavango Delta, Botswana.
(2006) Harrison, Phillipa Anne.; Maharaj, Bridgemohan.
In recent years the use of tourism as a development strategy by Third World governments has increased, resulting in the intersection of international tourism and local resource utilisation patterns. The aim of this thesis is to critically assess the impact of tourism in the utilisation and management of natural resources in the Okavango Delta in Botswana. More specifically, the study appraises the current state of tourism and natural resource utilisation and management in the Okavango Delta; assesses the past and present forms of resource utilisation practised by the local inhabitants scattered throughout the Delta area; focuses on the implementation of government policy regarding resource use; highlights past and present relationships between tourism and resource utilisation; and examines the impact of tourism on the areas resources, environment and local inhabitants. Research has shown that the Okavango Delta, which is Botswana's primary tourism area, is faced with a number of social, economic and environmental challenges. These include extreme levels of poverty, especially in the rural areas; lack of infrastructure; competition over land and resources; growing regional inequality; social degradation; increased imports leading to foreign exchange leakages; changes in subsistence strategies and increased 'rural-urban' .migration; and the loss of control of the region by the local population to the global tourism system. The Okavango Delta is in the process of undergoing a change from traditional, rural, subsistence economies and livelihoods to capitalist, commercial-driven economic structures. In the Okavango Delta, as in many places around the world, people are in the process of being integrated into national level political, social and economic institutions, both within and outside of their control. The creation of employment for the local population, the sustainable use of the Delta and its resources, the development of the local agricultural industry, the continued growth of the tourism industry, and striking a balance between the conservation/preservation of the Okavango and meeting the water requirement needs of Angola, Namibia, and Botswana's growing populations are amongst the key concerns present in the area. 11 Tourism in the Okavango Delta is directly dependent upon the utilisation of the region's natural resources of wildlife, water and natural vegetation areas for the industry. As such, tourism has increasingly impacted upon the way, and degree to which, these resources are managed and utilised, hence being identified as a key factor effecting the resource sector. If the Government of Botswana is to develop a tourism industry which fosters environmental and natural resource preservation, rather than maintaining a heavy dependence on limited and fragile resources, a better understanding of the relationship between the two sectors is necessary. Enhancing the positive linkages between tourism and natural resource utilisation in the Okavango Delta region represents an important means to stimulate increased natural resource and environmental protection, and improve the distribution of tourism benefits to rural communities. amongst the key concerns present in the area. Tourism in the Okavango Delta is directly dependent upon the utilisation of the region's natural resources of wildlife, water and natural vegetation areas for the industry. As such, tourism has increasingly impacted upon the way, and degree to which, these resources are managed and utilised, hence being identified as a key factor effecting the resource sector. If the Government of Botswana is to develop a tourism industry which fosters environmental and natural resource preservation, rather than maintaining a heavy dependence on limited and fragile resources, a better understanding of the relationship between the two sectors is necessary. Enhancing the positive linkages between tourism and natural resource utilisation in the Okavango Delta region represents an important means to stimulate increased natural resource and environmental protection, and improve the distribution of tourism benefits to rural communities.
A study of the environmental impacts (natural and anthropogenic) on the estuaries of KwaZulu-Natal, South Africa : implications for management.
(2008) Chili, Nsizwazikhona Simon.; Pillay, Srinivasan Seeni.
This thesis documents eight estuaries that are situated on the northern coastline of KwaZulu-Natal viz.: St Lucia, Mfolozi, Zinkwazi, Mvoti, Mngeni and those of the South i.e. Isipingo, Manzimtoti and Mkomazi. The documentation is aimed at undertaking a holistic approach on estuaries of KwaZulu-Natal approximately 10% and determines the influence of anthropogenic and natural impacts upon their health status. The study has also analysed selected sample estuaries of KZN in terms of their general natural characteristics, looked at the morphological features, riparian vegetation and land use directly from site visits and from aerial photographys, and determined the influence of anthropogenic and natural impacts in the estuaries. It also assessed the health status of the estuaries, proposed appropriate management strategies and reviewed the current status of estuaries in KZN / southern Africa. The researcher employed quantitative approach as a viable and the most relevant method where a holistic approach has been used. This was achieved through the execution of various techniques. For instance, reconnaissance survey was conducted including the usage of aerial photographys and topographical maps. Data was also collected using the YSI 6920 model. The study was also undertaken in order to determine whether the KwaZulu-Natal estuaries were still having a nursery function, which appeared to be losing when considering both primary and secondary activities that took place in the catchment areas. All of these estuaries were under a severe stress and pressure through natural and anthropogenic phenomenon. They were all suffering and gradually getting contaminated and depleted through anthropogenic activities that took place uncontrolled in their catchmenmt areas. Findings also show humans as the main culprits for estuarine contamination and degradation. It was discovered that about 84.2% of the catchment areas within the study area was human occupied. Their suffering differed as it depended on the extent in which catchment areas were utilized. Where anthropogenic activities took place alarmingly, estuaries also suffered a great deal. This posed a challenge to ecologists, hydrologist and environmentalists generally, and to physical geographers specifically since they regard estuaries as very important for their nursery functions and ecological balances. Mfolozi and St Lucia estuaries were found to be little affected from direct anthropogenic effects. Pollutants accumulating in the systems may have come from farmlands in the north of the Mfolozi and from the town of St Lucia in the case of the St Lucia estuary. However, more negative effects were clearly due to excessive sedimentation. The study has revealed that the Mfolozi mouth position had been artificially relocated on several occasions since 1952 by human intervention in the system. In these situations, the Mfolozi mouth may be located between one and two kilometres south of the St-Lucia mouth. Two estuaries, Mvoti in the north and Isipingo in the south were found to be the most affected water bodies by human activities occurring in the catchment areas and this has led to them having unhealthy water status. It was found that through anthropogenic interference, there were changes in the nature of runoff and water quality that was attributed to industrial pollution, runoff from agricultural activities, sewage effluent and the runoff from urban areas. There is evidence of extremely poor catchment management practices as proved by the poor state of many estuaries along the KwaZulu-Natal coast. The study recommended that for the important future well being of these estuaries, various tiers of catchment management authority must be put in place by the Department of Water Affairs and Forestry. The local authorities must proactively manage land uses and anthropogenic activities on and around the estuaries in order to minimise potential impacts on the systems.
The estimation of Eucalyptus plantation forest structural attributes using medium and high spatial resolution satellite imagery.
(2008) Gebreslasie, Michael Teweldemedhin.; Ahmed, Fethi B.; van Aardt, Jan.
Sustaining the socioeconomic and ecological benefits of South African plantation forests is challenging. A more systematic and rapid forest inventory system is required by forest managers. This study investigates the utility of medium (ASTER 15 m) and high (IKONOS 1-4 m) spatial resolution satellite imageries in an effort to improve the remote capture of structural attributes of even-aged Eucalyptus plantations grown in the warm temperate climatic zone of southern KwaZulu-Natal, South Africa. The conversion of image data to surface reflectance is a pre-requisite for the establishment of relationships between satellite remote sensing data and ground collected forest structural data. In this study image-based atmospheric correction methods applied on ASTER and IKONOS imagery were evaluated for the purpose of retrieving surface reflectance of plantation forests. Multiple linear regression and canonical correlation analyses were used to develop models for the prediction of plantation forest structural attributes from ASTER data. Artificial neural networks and multiple linear regression were also used to develop models for the assessment of plantation forests structural attributes from IKONOS data. The plantation forest structural attributes considered in this study included: stems per hectare, diameter at breast height, mean tree height, basal area, and volume. In addition, location based stems per hectare were determined using high spatial resolution panchromatic IKONOS data where variable and fixed window sizes of local maxima were employed. The image-based dark object subtraction (DOS) model was better suited for atmospheric correction of ASTER and IKONOS imagery of the study area. The medium spatial resolution data were not amenable to estimating even-aged Eucalyptus forest structural attributes. It is still encouraging that up to 64 % of variation could be explained by using medium spatial resolution data. The results from high spatial resolution data showed a promising result where the ARMSE% values obtained for stems per hectare, diameter at breast height, tree height, basal area and volume are 7.9, 5.1, 5.8, 8.7 and 8.7, respectively. Results such as these bode well for the application of high spatial resolution imagery to forest structural assessment. The results from the location based estimation of stems per hectare illustrated that a variable window size approach developed in this study is highly accurate. The overall accuracy using a variable window size was 85% (RMSE of 189 trees per hectare). The overall findings presented in this study are encouraging and show that high spatial resolution imagery was successful in predicting even-aged Eucalyptus forest structural attributes in the warm temperate climates of South Africa, with acceptable accuracy.

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