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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.
11

The distribution and seasonal availability of surface water on the Manyeleti Game Reserve, Limpopo Province, South Africa

Cronje, HP, Cronje, I, Botha, AJ 13 October 2005 (has links)
The availability and abundance of surface water on the Manyeleti Game Reserve was quantified to provide information towards the development of a water provision policy. A total of 696 water source sites were located with a mean distance of 223.3 m apart. The water source sites (natural and artificial) were monitored seasonally to describe the seasonal availability of surface water on the Manyeleti Game Reserve. There were significant relationships between seasonal rainfall and the number of water source sites and maximum distance between sites. The large number of water sources is regulated by climatic progression and thus water provision on the Manyeleti Game Reserve follows a natural cycle linked primarily to rainfall. Water sources that dry up towards the dry seasons need to be supplied with water during drought periods in order to maintain game numbers without causing rangeland degradation. A water provision model that incorporates all the variables of the Greater Kruger Park Conservation Area, with particular reference to the smaller conservation areas within it, should become a research priority.
12

You may not be as smart as you think : an alternative account of the Dunning-Kruger effect

Nunes, Tylah January 2015 (has links)
Perception of abilities plays an important role in informing one’s decisions at times and often in forming one’s self perception. The Dunning-Kruger effect is a fascinating and empirically observable bias in which top performers tend to make more accurate estimations of their ability than bottom performers. The current theory states that the effect is caused by top performers possessing greater metacognitive ability than bottom performers. There have been many alternative theories and explanations proposed to explain the observed Dunning-Kruger effect. The current study is the first to test whether top and bottom performers base their predictions on inflated preconceived notions of ability, rather than their metacognitive ability. This theory proposes that if top and bottom performers both based their predictions of performance on their preconceived notions of ability it would create a Dunning-Kruger effect. This presupposes that that both top and bottom performers make above average estimates of performance as they hold preconceived notions of above average ability. Thus, top performers’ predictions of performance would be most accurate as their performance would be above average, whereas bottom performers would most overestimate their performance as their performance would be below average. The intention of this study was, thus, to assess whether either top or bottom performers based their predictions of performance on preconceived notions of ability or using metacognitive ability. A total of 97 university students were divided into two groups and given an identical test, one group containing 49 participants were told the test measured Logical Thinking and the remaining 48 participants were told the test measured Computational Mathematics. After completing the test, which was a 23 item preparatory test for the LSAT, participants were asked to estimate their ability in the domain being assessed, their performance relative to their peers and their score out of 23. A t-test was used to compare the two groups and it was found that the Logical Thinking and Computational Mathematical group made significantly different predictions of ability and therefore held significantly different preconceived notions of ability. Further t-tests were used to compare the estimates of ability and predictions of performance of the two groups of top and bottom performers. A significant difference was found between the two groups of top performers’ prediction of ability. However, there was no significant difference between any of the other scores of the two groups of top and bottom performers. Therefore, the alternative theory that top and bottom performers base their predictions of performance on preconceived notions of ability was found to be invalid. Therefore, the current theory which states that top performers’ superior metacognitive ability allow them to make more accurate estimates of performance than bottom performers is still the best account for the Dunning-Kruger effect. / Dissertation (MA)--University of Pretoria,2015. / Psychology / Unrestricted
13

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
14

The effect of elephant utilisation on the Sterculia rogersii and Adsonia digitata populations of the Kruger National Park

Kelly, Henry Lyle Patrick 03 April 2006 (has links)
This study assesses elephant induced damage and mortality of baobab and common star-chestnut trees in the northern Kruger National Park. Comparisons are made between the populations north and south of the Luvuvhu River. The density, population size and age structure are estimated. The population structure of neither species has been shaped by elephant utilisation. While the baobab population has a healthy age distribution, that of the star-chestnut population shows that recruitment has declined in recent decades. Utilisation has been found to be higher in the south as a result of higher elephant densities, although recently damage has been greater in the north. Damage increases with tree size. The mortality of baobabs is lower than in other areas where elephants and baobabs co-exist. Elephants are not playing a significant role in mortality of either tree species and management of factors other than elephant is required to improve regeneration rates of these species. / Dissertation (MSc (Wildlife Management))--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted
15

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.
16

Free-living nematodes from rivers in the Kruger National Park

Botha, Annelize Susan 11 February 2014 (has links)
D.Phil. (Nematology) / This was the first study on aquatic nematodes from the Kruger National Park. Samples were taken more or less randomly over a period of two years from the four main rivers in the park, viz. the Crocodile, Sabie, Olifants and Luvuvhu rivers. A total of 33 species representative of 24 genera were found. Dorylaimida seemed to be dominant in most of the sampling sites in the Sabie, Olifants and Luvuvhu Rivers, but there was no dominant group in the Crocodile River. Five new Dorylaimida species are described: Dorylaimus deaconi spec. nov., Laimydorus olifanti spec. nov., Laimydorus africanus spec. nov.; proleptonchus krugeri spec. nov. and Aporcelaimellus glandus spec. nov. Previously known dorylaim species which were redescribed in detail are Mesodorylaimus sp.cf paralitoralis Basson & Heyns, 1974; M. potus Heyns, 1963, M. aegypticus (Andrassy, 1958), Aquatides thornei (Schneider, 1937), Afractinolaimus zairensis (Baqri, Coomans & Van der Heiden, 1975) and Oxydirus gangeticus Siddiqi, 1966. Further dorylaim species recorded are Aporcelaimellus micropunctatus Botha & Heyns, 1990, Discolaimus monoplanus Heyns, 1963, D. major Thorne, 1939, Xiphinema italiae Meyl, 1953, Thornenema baldum (Thorne, 1939), Tyleptus striatus Heyns, 1963 and Dorylaimellus (Axodorylaimellus) caffrae (Kruger, 1965) . The following Tylenchida species were found: Hemicycliophora labiata Colbran, 1969, Helicotylenchus africanus (Micoletzky, 1916) and Scutellonema brachyurum (Steiner, 1939). Three Araeolaimida species were recorded, viz. Chronogaster africana Heyns & Coomans, 1980, Plectus cirratus Bastian, 1865 and Rhabdolaimus terrestris de Man, 1880. The latter species is redescribed in full collected and (de Man, 1979). Only one species of the Cromadorida viz. Achromadora ruricola 1880), Enoplida viz. Eutobrilus annetteae (Joubert & Heyns, Monhysterida viz. Monhystera somereni Allgen, 1952, were Detailed descriptions are given to incorporate additional morphological information obtained. Brief descriptions and new distribution records are also given for Mononchus truncatus Bastian, 1865, M. aquaticus Coetzee, 1968 and Mylonchulus minor (Cobb, 1893) of the Mononchida and Ironus longicaudatus de Man, 1884 and I. ignavus Bastian, 1865 of the Iro~idae.A diagnostic compendium for the Mesodorylaimus species of South Africa and a checklist of the free-living and plant parasitic nematode species from both terrestrial and aquatic habitats in the park are also included. Most of this work has already been published or submitted for publication in scientific journals and is presented in this thesis in the same format as required by the editors of the journals concerned.
17

A study of the ecology, behaviour and systematics of Tockus Hornbills

Kemp, Alan Charles January 1973 (has links)
During the last decades ecology and behaviour have become of major importance in African ornithology. Not only have more individual species been studied in detail, but behaviour and ecology have been used in a more general sense in regional works (Benson et al 1971} and in zoogeographical treatises (Moreau 1966, Hall and Moreau 1970). As part of a world- wide trend, behaviour and ecology have also become important in systematics and taxonomy eg. Hall's 1963 study of francolin, and Benson et al's 1971 erection of the bush shrike family Malaconotidae. This dissertation fits into this trend, beginning with a detailed study of the ecology and behaviour of three species of hornbill of the genus Tockus, and extending the observations in less detail to five other members of the genus. Combined with the literature, these observations allow an analysis of the systematics and evolution of the genus Tokus to be undertaken, as well as supplying descriptive information on Tokus biology. Intro. p. 1.
18

Anthropogenic threats to resident and dispersing African wild dogs west and south of the Kruger National Park, South Africa / Antropogenic threats to resident and dispersing African wild dogs west and south of the Kruger National Park, South Africa

Watermeyer, Jessica Patricia January 2012 (has links)
African wild dog Lycaon pictus populations are declining and the species is listed as Endangered by the IUCN. The Kruger National Park (KNP) is home to the only viable population of wild dogs in South Africa, but census results reveal consistently low numbers since the late 1990s. Wild dogs display wide-ranging behaviour and it is possible that the species might frequently use unprotected lands adjacent to the KNP. However, very little is known about wild dog movements beyond the boundaries of the KNP, and whether or not adjacent land owners are tolerant of the species. Significantly, threats along the boundaries may have negative consequences for the KNP population. This research investigated the dispersal habits of wild dogs beyond the western and southern boundaries of the KNP, and gathered information on human tolerance, and anthropogenic threats in an area of mixed land use. The land west of the KNP presented the best prospect for wild dog range expansion. The wild dog packs operating outside the KNP had smaller home ranges and less home range overlap than the packs operating within the KNP. In addition, my data suggested that the development of conservancies and the formation of ecotourism-based land use practices would be beneficial for wild dog conservation. Failed wild dog dispersals due to snaring and human persecution could threaten the genetic stability and persistence of the KNP population. Therefore, raising awareness and an understanding of the plight of wild dogs is important for improving land owner perception and tolerance outside of protected areas. The rapidly increasing human population continues to infringe on protected lands and fragment landscapes, thus cooperation from individual land owners is vital for the conservation of free-ranging large carnivores.
19

The development of an integrated wildlife disease surveillance and monitoring system for the disease management in free ranging wildlife in the greater Kruger Park

Oosthuizen, Johan 02 1900 (has links)
The study was conducted in the Greater Kruger National Park Complex (GKNP), which consists of the Kruger National Park (KNP) and adjacent private game reserves and focuses primarily on the following objectives: • To monitor and evaluate the standard of the existing disease surveillance programmes for the following diseases, Foot and Mouth, Anthrax, Tuberculosis, Brucellosis and Rabies, within the Kruger National Park and adjacent private game reserves by evaluating the level of competency and knowledge in field rangers, field guides and trails rangers with regard to these specific diseases. It can be stated that important differences exist between disease surveillance techniques used for domestic animals and those used for wildlife (Bengis, R.G., Kock, R.A., & Fischer, J., 2002). According to Morner, T., Obendorf, D.L., Artios, M., & Woodford, M.H., 2002, it is more difficult to monitor diseases in wildlife than in domestic animals because wild animals are not constrained by boundaries and can roam over large. distances. For significant diseases in wildlife, an active surveillance programme may be the preferred approach with the aim to collect a certain number of samples from a target population (live or dead animals) to determine the point prevalence of certain pathogens. Active veterinary participation is essential in protected area management, with emphasis on training of technicians, rangers and field biologists with regard to specific diseases and their clinical signs, surveillance and sampling techniques, data collection, and reporting. For the purpose of this study, data collection was conducted by means of a questionnaire drawn up according to the related critical points as described in the Dufour grid (Dufour, 1998). The results of this study clearly showed a need to address certain important aspects regarding a wildlife disease programme within the GKNP. A more efficient wildlife disease surveillance programme, which included more specific and “hands-on” trained staff, would definitely ensure a better early warning system which would detect new or emerging disease outbreaks. / M. Tech. (Nature Conservation))
20

Determinants of grass production and composition in the Kruger National Park.

Zambatis, Nicholas. January 2003 (has links)
The dynamics and complexities of climate-soil-vegetation relations in the Kruger National Park are poorly known. Although primary production and composition of the grass layer are very important components of the Park's ecosystem, equally little is known about the determinants of these parameters. A better understanding of these processes and relations will be of value to the management of this Park, as well as providing a better insight into these complex dynamics. A study was consequently undertaken covering a 14-year period to identify the most important determinants of above-ground grass production and composition. At the core of the study is the soil water balance. The use of evapotranspiration data in a study of this nature is however not absolutely essential, provided a variety of rainfall parameters are used, though it has the important advantage of providing a much more detailed and more complete insight into the relations of the grass sward with its environment. Stepwise and tree regression procedures were used to identify the important factors. It is concluded that rainfall in its various forms is the primary determinant of grass production, standing crop, and composition, the latter either as perennials or Decreasers. Secondary determinants, in varying degrees of importance, are the thickness and base status of the A horizon, distance to permanent drinking water, and competition by woody plants. Herbivore utilization is insignificant or at most, plays a relatively minor role. Herbivores appear to exert a negative influence on Decreaser abundance only when soil moisture stress exceeds a threshold level. When this is exceeded, relatively low herbivore densities are apparently sufficient to reduce Decreaser abundance. The definitions of Decreasers and Increasers consequently require revision to take into account the overriding influence of environmental factors, particularly those of soil moisture stress. The calibration of the disc pasture meter was re-evaluated. The relation between mean disc height and standing crop is non-linear. Up to a mean disc pasture meter height of 260 mm, the correlation between this parameter and above-ground standing crop is very strong (r2 = 0.95; P<0.0005). Beyond this height, the correlation is very poor (r2 =0.09; P<0.0005), apparently being strongly influenced by the structure of the grass plant, with tall grasses, or grasses with highly lignified culms resulting in a weaker correlation. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

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