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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

Market profiles and trade in medicinal plants in the Lowveld, South Africa

Botha, J, Witkowski, E T F, Shackleton, Charlie January 2004 (has links)
Rising demand for medicinal plants has led to increased pressure on wild plant populations. This, combined with shrinking habitats, means that many species in South Africa are now facing local extinction. In 1997, a study was initiated to determine the extent of trade in medicinal plants in the South African Lowveld (the low lying plains to the east of the Drakensberg escarpment), and to investigate socio-economic factors influencing trade and resource management. Trade was not as extensive in the Lowveld as in major urban markets such as Durban or the Witwatersrand (Johannesburg and surrounding towns), either in terms of the quantity, number or range of species sold, or the numbers of people relying on the trade for an income. In markets assessed in Mpumalanga Province, 176 species were identified (71% of the vernacular names encountered in the market place), representing 69 plant families. In Limpopo, 70 different species were identified (84% of the vernacular names encountered in the market place), representing 40 families. Imports were significant in Mpumalanga (33% of the plants on offer), mainly from Mozambique. A detrended correspondence analysis showed substantial differences between species traded in Mpumalanga and those sold in Limpopo. There was little variation in the species stocked by vendors in Mpumalanga, regardless of the season, the attributes of the seller, or whether business was carried out in urban or rural areas. In contrast, there was considerable variation in the stock inventories of the Limpopo traders. Despite the lower levels of local trade, increased harvesting pressure is being experienced regionally, to meet demand in metropolitan centres such as the Witwatersrand. This study showed considerable local variation and complexities in the harvesting and marketing of medicinal plants, with both a national and an international dimension. This dual spatial scale presents both opportunities and challenges in the management of these plants, which need to be addressed simultaneously, particularly with respect to research requirements and development of predictive models and capacity. Cooperation in conservation strategies and policies is required at regional, national and international levels, while ensuring that management initiatives take into account local market conditions and the socio-economic realities facing both consumers and those who depend on the trade for their livelihoods.
2

Recovery, resilience and stability of piospere systems in the Kruger National Park.

Matchett, Katherine Jean. 27 May 2014 (has links)
Water provision is an important tool in the management of savanna ecosystems. Artificial water sources are a potential focus for degradation (biodiversity and loss of ecosystem resilience at a range of spatio-temporal scales), because they alter plant-animal interactions and soil function and stability, through the creation of piospheres. This study was undertaken as part of a drive by the Kruger National Park (KNP) to enable managers to integrate artificial waterhole management (e.g. waterhole closure or rotation) when setting goals for heterogeneity and biodiversity conservation in the park. The over-arching goal was to quantify the relationship between water provision and different attributes of heterogeneity, as part of a broader initiative to place water provision and piospheres within an ecosystem threshold framework. Herbivore utilisation gradients (piospheres) around artificial waterholes in the KNP, described in 1990, were resurveyed in 2006-2007, against a backdrop of waterhole closure in the KNP, to contribute to an understanding of the factors governing recovery and resilience in grazing systems. The responses of the plant community and soil parameters to a relaxation of herbivore utilisation pressure around closed waterholes (recovering piospheres) were examined, as were changes in the same parameters at sites that have remained open (active piospheres). These ecosystem properties were considered in relation to structural and functional ecosystem thresholds, and the piospheres surveyed incorporated a range of rainfall and edaphic gradients in the KNP. Herbaceous basal cover and soil infiltration capacity both increased significantly between 1990 and 2006/7, regardless of waterhole status. This was linked to higher rainfall in 2006/7, compared to 1990. The only vegetation variables to respond consistently to distance from water were the remote-sensed Normalized Difference Vegetation Index (NDVI) and herbaceous species composition. NDVI increased with distance from water, and annual grasses and forbs were most abundant close to water. Perennial, disturbance-sensitive climax species increased in abundance further from water. Soil analyses (N, P, pH, organic matter, and texture) and field measurements (infiltration, compaction) revealed no systematic piosphere patterns. Waterhole closure did not result in soil or vegetation recovery, but piosphere intermittency and the increases of basal cover and infiltration rate indicated that ecosystem resilience has not been compromised vii by long-term artificial water provision in the KNP. This study has shown that the traditional piosphere model is of limited use in sub-humid savanna ecosystems like the KNP during above-average rainfall periods. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
3

Temporal and spatial variations of tourists in the Kruger National Park.

Mearns, Kevin Frank 17 August 2012 (has links)
M.Sc. / OBJECTIVES Tourism in the Kruger National Park is closely linked to nature conservation. Tourism being the revenue earner and conservation the resource provider; this results in a mutually beneficial symbiosis. This finely tuned interdependence between tourism and conservation should be properly managed to ensure that tourism does not become a self-destructive process, destroying the very resources on which it is based. Mounting pressure from central government is forcing the National Parks Board to become financially independent of State grants. Tourism provides the most viable solution towards achieving financial independence. All the national parks in South Africa will therefore have to make a concerted effort to accommodate and attract more tourists. The Kruger National Park, being the largest national park (1 948 528 hectares), will have to make a major contribution towards financial independence. In order to achieve this goal, tourism in this Park will have to be planned and managed more effectively. It is within this context that this study was initiated. In order to facilitate future tourism planning and management, the study will investigate the number of tourists visiting the Kruger National Park as well as the occupation of accommodation by tourists. These results will in turn be used to investigate the tourist carrying capacity of the Park and to make suggestions regarding the Park's tourism management policies. RESEARCH METHOD As a result of the primarily descriptive nature of the investigation relating to the number of tourists visiting the Park as well as the occupation of accommodation by tourists, the research will include diagrammatic and cartographic representations of the data. In order to explain the temporal and spatial variations of the tourists in the Kruger National Park, a correlation and regression analysis was used in conjunction with non-tourist variables (which include both socio-economic and physical variables). The results obtained in the above investigation were used to study the physical and perceptual tourist carrying capacity. Physical tourist carrying capacity was researched by indicating the percentage occupation of available accommodation and available day visitor quota. As a result of the its subjective nature, the balance between the costs and benefits associated with gaining a holiday experience was used in conjunction with the number of visitors to the Park in order to determine the perceptual tourist carrying capacity. RESULTS The number of visitors to the Park as well as the occupation of accommodation by tourists both indicated that large temporal and spatial variations exist. The temporal variations in tourist data were best explained by school holidays. An obvious relationship exists between school holidays and the number of visitors to the Park. The spatial variation was best explained by distance from the PWV and rainfall. The distance from the PWV (now Gauteng Province) indicates the strong influence of this region as a source area for tourists to the Park. Rainfall in the Park influences the type of vegetation, which in turn influences the distribution and population densities of animals which are sought after by tourists. With regard to the tourist carrying capacity, the results showed that the physical tourist carrying capacity is utilised below the optimum levels. More tourists can therefore be accommodated, particularly during non-school holiday periods. With reference to the perceptual tourist carrying capacity, it was found that it has been reached. The most important reason for this is the higher tariffs that are being charged.
4

The status, distribution and ecology of the Klipspringer in the Kruger National Park

Kruger, Marius 05 October 2005 (has links)
The status, distribution and ecology of klipspringer were studied in the Kruger National Park. For the status and distribution, the Kruger National Park south of the Olifants River was used as the study area. Data on the status and distribution were gathered from all the ranger sections in the study area with the use of a non-sampling method, namely a systematic search. The results showed that the klipspringer population in the Kruger National Park is secure with a patchy distribution consisting of 773 individuals in the study area and a sex ratio of one male per 1.1 female. The ecology of the klipspringer was studied in a specific study area on the Nwatindlopfu spruit between Skukuza and Tshokwane where five klipspringer individuals were radio collared. The aspects covered in the study on the ecology of klipspringer, were the activities associated with environmental and vegetation related variables as well as scent-marking. It was found that vegetation is the determining factor in the habitat selection of klipspringer in the Kruger National Park, in that it provides both shelter and food. The ideal klipspringer habitat can be described as an area that has limited access to other ungulates that can attract predators. The vegetation should consist of palatable plant species that could be utilized by klipspringer, and must also provide sufficient shelter against possible danger. Klipspringer scent marks were surveyed in a specific klipspringer range in the Kruger National Park with the use of a strip transect method. Both the male and the female klipspringer scent-mark their ranges. A pair of pre-orbital glands below the eyes produces the scent. The secretion produced is a sticky milky substance that is deposited on a suitable twig. The results showed that klipspringer in the Kruger National Park scent-¬mark more frequently on the boundaries of their ranges and also more on those sides where there is another resident klipspringer group. / Dissertation (MSc (Wildlife Management))--University of Pretoria, 2005. / Animal and Wildlife Sciences / unrestricted
5

Dorylaimida uit die Nasionale Krugerwildtuin

01 September 2015 (has links)
M.Sc. / This study embraces three facets, namely a checklist of all the freeliving and plantparasitic nematodes, reported from the Kruger National Park, descriptions of the nematode species found during the present study, and a historical review of the family Aporcelaimidae with emphasis on the genus Aporcelaimellus Heyns, 1965, a species compendium and descriptions of several new species ...
6

Adopting a heterogeneity paradigm for understanding and managing elephants for biodiversity : a case study in riparian woodlands in Kruger National Park

Gaylard, Angela January 2016 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2015. / Decades of study devoted to solving the “elephant problem” have generally concurred that increasing elephant populations inevitably reduce biodiversity. However, recent evidence suggests that such reductions can be accompanied by increases in other components of biodiversity, and that ultimately elephant effects are scale-dependent. Although this new perspective now underpins elephant management strategies in savannas such as the Kruger National Park (KNP), South Africa, few empirical studies in support of this strategy have incorporated the contribution of spatial context, or allowed for the emergence of relevant scales, in their interpretations of heterogeneity. Moreover, use of traditional modes of scientific enquiry and statistical approaches for investigating heterogeneity in complex systems have been challenged. Recent advances in spatial statistics, together with an alternative mode of science that draws upon multiple lines of converging evidence rather than testing narrowlyfocused hypotheses, have the potential to address these challenges. However, their practical application for understanding elephants as agents of change remains lacking. Riparian zones along the ephemeral rivers in northern KNP provided an ideal landscape to explore the spatial and temporal parameters of elephant effects in response to surface water, as a critical resource, and hence to develop a framework for a heterogeneity approach for understanding and managing elephants as agents of change in savannas.
7

A spatial model to determine the location and extent of sodic sites in the Shingwedzi and Ripape river catchments of the Kruger National Park using remote sensing classification techniques and satellite imagery

Kleyn, Linda Gail 01 February 2012 (has links)
MSc., Faculty of Science, University of the Witwatersrand, 2011 / Sodic soils are salt-affected soils which are high in sodium in relation to magnesium and calcium. Commonly called sodic sites in the Kruger National Park (KNP), these patches exhibit unique functional characteristics due to the high levels of sodium which cause surface crusting, cracking and the dispersion of clay particles. The aim of this study is to use satellite imagery to map sodic sites in the KNP at different spatial and spectral scales, giving the best option for a repeatable, semi-automated classification. The resultant map of sodic sites for the KNP will be used as a management tool and for future research projects. A field test for sodicity was necessary to collect sufficient ground truth samples for robust accuracy assessment of the image classification. Sodic soils are identified by measuring EC, pH and SAR which are highly variable within site and between testing methods, and therefore not useful for rapid ground truth classification of sodic soils in the field. The sodium level at which clay particle dispersion takes place varies between soils, but is measurable in the field using the Emerson dispersion test. Laboratory tested sodic soil sites from previous research re-tested in this study showed positive results for dispersion of clay particles in water. The physical properties of sodic sites described in the literature and observed in the field were applied to classify sodic sites in the KNP in the field using a decision tree, together with results from the dispersion test and the observed presence of the grass species Sporobolus iocladus. Landsat 7 and SPOT 5 imagery cover the whole park, with ASTER, CAO hyperspectral, LiDAR and black and white orthophotos available for selected areas. The topography elements of crest and footslope were derived from the STRM 90m digital elevation model (DEM). Image preprocessing to top of atmosphere reflectance was performed where necessary and visual enhancement techniques and transformations were applied to derive the normalised difference vegetation index (NDVI) and other indices. Spectral signatures were checked against spectral signature libraries, and the class separation was tested using the cluster analysis of spectral signatures. MODIS NDVI averages placed the imagery in phenological context. Object-based image analysis using eCognition was applied to classify the sodic sites of the Shingwedzi and Ripape River catchments. The input imagery was segmented into ecologically meaningful patches and classification accuracy was assessed using the field samples collected using the decision tree to identify four classes: sodic sites (bare and woody), river sand, riverine vegetation and savanna areas. Comparison of the accuracy assessments for the Shingwedzi study site showed that the Landsat 7 and SPOT 5 classification algorithms gave an overall kappa index accuracy of 89% and 78% respectively, and a sodic site kappa index of 90% and 89%. Validation results using the ground truth samples gave an overall kappa index accuracy of 61% for Landsat 7 and 52% for SPOT 5, with a sodic site kappa index of 49% and 39% respectively. The classification algorithms were applied to the Ripape study site for Landsat 7 and SPOT 5 with repeatable results for the SPOT 5 imagery of 88% overall kappa index and 81-93% kappa index for sodic sites using similar seasonal imagery in the wet to early dry season. The Landsat 7 classification algorithm was applied to the entire KNP based on the repeatability results of 56% overall kappa index and 60% sodic site kappa index for the Ripape site. The quest for a repeatable algorithm to classify sodic sites from satellite imagery has been met by the SPOT 5 imagery using scenes acquired at similar seasonal stages. The late wet season or early dry season imagery was used to apply the classification algorithm with the best success. Changes in size or shape of sodic sites over time requires very high resolution imagery and further studies to understand where the edge of sodic sites are detected from imagery, and how the phenology of the vegetation growing on these sites affects detecting any change in size of the sodic site.
8

Choice of social environment of male buffalo (syncerus caffer) in the Kruger National Park, South Africa.

Hay, Craig Thomson January 2007 (has links)
Thesis (MTech. degree in Nature Conservation ) - Tshwane University of Technology, 2007. / The tendency for male and female buffaloes to live separately outside the breeding season is termed sexual segregation. A number of hypotheses have being proposed to explain this behavior. This study, in an area with an intact predator community, strongly support the predation-risk hypothesis and attempts to clarify the function of sexual segregation in buffalo in southern Africa. It also contributes to understanding the possible consequences of selective removal of males for hunting or culling purposes.
9

Determining the role and relative importance of predator avoidance and nutrition as processes influencing herbivore utilisation of burnt areas in Satara, Kruger National Park, South Africa

Luhdo, Zoe 11 May 2016 (has links)
A Dissertation submitted to the Faculty of Science in fulfilment of the requirements for the degree: Master of Science In School of Animal, Plants and Environmental Sciences, University of Witwatersrand Johannesburg 2015 / This study aimed to determine the role and relative importance of predator avoidance and nutrition as processes influencing herbivore utilisation of burnt areas, at Satara, Kruger National Park by using variation in fire size and fire season. The driving factors investigated included forage quality, forage quantity, vegetation structure and predation risk. The effect of fire size and season on the landscape was tested by recording grass height, greenness, grass nutrient sampling and visibility. Results showed that fire size and season had a significant impact on the physical environment by decreasing grass/forage quantity post-fire but increasing grass/forage quality. Over time the plots returned to near pre-fire conditions, with forage quantity increasing (grass height and biomass) and forage quality decreasing (nitrogen availability). Visibility increased immediately post-fire, more significantly in regards to herbivores with their heads in a “head-down/grazing” position than in a “head raised/vigilant” position. As with forage quantity and quality, visibility returned to near pre-fire conditions at the end of the study sampling period. The response of animals to these changes in the environment was recorded through dung counts, camera traps and behavioural observations. I found that there was increased use of burnt plots post-fire through comparing herbivore presence on plots burned in different sizes and seasons, day/night utilisation of plots, and using behaviour data I could determine to what extent forage and predation risk were driving the use of burnt areas. I focused on three herbivore species (Aepyceros melampus, Connochaetes taurinus and Equus quagga) which varied in terms of body size digestive systems, forage type, and social behaviour. As expected, I found that predation risk did appear to be more important in driving the behaviour of the smaller-bodied herbivores but both nutrient requirements and susceptibility to predation were shown to play a role in explaining the use of burnt areas for all three herbivore species. Variation between plots in environmental factors such as tree density, forb percentage and distance to water, were found to be not significant and thus did not confound our results
10

Modelling dispersal processes in impala-cheetah-lion ecosystems with infection in the lions

Mbava, Willard January 2016 (has links)
The study involved the predator-prey interaction of three species namely the predator (Cheetah Acinonyx jubatus), the super-predator (Lion Panthera leo), and their common prey (Impala Aepyceros melampus). The study area is the Kruger National Park. The predator being an endangered species, faces a survival problem. It is frequently killed by the super-predator to reduce competition for prey. The super-predator also scares away the predator o_ its kills. The prey forms the main diet of the predator. The plight of the predator motivated the author to formulate disease and reaction-diffusion models for the species interactions. The purpose of the models were to predict and explain the effect of large competition from the super-predator on the predator population. Important parameters related to additional predator mortality due to presence of super-predator, the disease incidence rate and induced death rate formed the focal points of the analysis. The dynamics of a predator-prey model with disease in super-predator were investigated. The super-predator species is infected with bovine Tuberculosis. In the study, the disease is considered as biological control to allow the predator population to regain from low numbers. The results highlight that in the absence of additional mortality on the predator by the super-predator, the predator population survives extinction. Furthermore, at current levels of disease incidence, the super-predator population is wiped out by the disease. However, the super-predator population survives extinction if the disease incidence rate is low. Persistence of all populations is possible in the case of low disease incidence rate and no additional mortality imparted on the predator. Furthermore, a two-species subsystem, prey and predator, is considered as a special case to determine the effect of super-predator removal from the system, on the survival of the predator. This is treated as a contrasting case from the smaller parks. The results show that the predator population thrives well in the total absence of its main competitor, with its population rising to at least twice the initial value. A reaction-diffusion three-species predator-prey model was formulated and analysed. Stability of the temporal and the spatio-temporal systems, existence and non-existence of stationary steady state solutions were studied. Conditions for the emergence of stationary patterns were deduced. The results show that by choosing the diffusion coeffcient d2 > _D 2 suffciently large, a non-constant positive solution is generated, that is, stationary patterns emerge, depicting dispersal of species. Predators were observed to occupy habitats surrounding prey. However, super-predators were observed to alternate their habitats, from staying away from prey to invading prey habitat. In the investigation, strategies to determine ways in which the predator species could be saved from extinction and its population improved were devised, and these included isolation of the predator from the super-predator.

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