Thesis (MBA (Business Management))--University of Stellenbosch, 2009.

Ph.D. (Zoology) / This project involves a detailed study of three South African antelope species, springbok, impala and blesbok. The study investigates the origins of sperm in terms of testicular histology and subsequently the major storage organ, the cauda epididymis. Sperm of these species were characterized in terms of their quality (morphology, motility, vitality characteristics among others and their physiology: when exposed to different media and cryopreservation protocols. Finally sperm fertilization biology of the three species and evaluation of fertilization and developmental success when using homologous and heterologous oocytes (relative comparison) were assessed. Cauda epididymal spermatozoa was recovered post-mortem from the testes of culled springbok (n =38); impala (n =26) and blesbok (n =42) during winter months in South Africa and cryopreserved in a Tris-fructose-citric acid extender (Biladyl) supplemented with 20% egg yolk and 7% glycerol under field conditions. Longevity of sperm was assessed in Tris and Citrate extenders and modified Tyrode lactate in vitro fertilization (IVF) media. Oocytes were collected from the ovaries of domestic cows (n =165), springbok (n = 72) and blesbok (n = 42) and matured in domestic cattle M199 maturation media supplemented with 10% FCS, 10IJg/mi LH, 10IJg/mi FSH and antibiotics. Heterologous (zona intact and zona free) and homologous fertilization was carried using a domestic cattle IVF protocol. Results were analysed using SPSS version 18.0 (Statcon, South Africa). Interspecies comparisons were made using parametric tests: paired t-test for the freezing effect, one-way analysis of variance (ANOVA), Mixed between-within subjects ANOVA for longevity, Non Parametric test for motility characteristics and least squares ANOVA for...

Habitat loss and fragmentation is a crisis affecting wildlife worldwide. In Tanzania, East Africa, a dramatic and recent (<80 years) expansion in human settlement and agriculture threatens to reduce gene flow among protected areas for many species of large mammals. Wildlife linkages can mitigate population isolation, but linkage designs lacking empirical justification may be controversial and ineffective. Connectivity conservation requires an understanding of how biogeographic factors shaped gene flow prior to habitat loss or fragmentation, however the history of interaction among populations is rarely known. The goal of my study was to provide context for connectivity conservation in central and southern Tanzania by identifying landscape features that have shaped gene flow for three ungulate species with different dispersal capabilities. I investigated historical patterns of connectivity for Maasai giraffe (Giraffa camelopardalis tippelskirchi), impala (Aepyceros melampus), and eland (Tragelaphus oryx) by estimating genetic structure among four to eight protected areas per species. Genetic structure changes very slowly among large populations and thus is likely to reflect historical processes instead of recent anthropogenic influences. I collected noninvasive DNA samples and generated microsatellite genotypes at 8 to 15 loci per species, then estimated genetic diversity metrics (allelic richness, AR, and expected heterozygosity, H[subscript E]) for each population (defined by reserve). I also calculated genetic distance (F[subscript ST] and Nei's unbiased genetic distance, D[subscript hat]) and an estimate of gene flow (Nm) between all population pairs for each species. To elucidate the possible causes of genetic structure between these populations, I tested for isolation by distance and isolation by resistance based on a suite of biogeographic factors hypothesized to affect gene flow. To do this, I created GIS-based resistance surfaces that assigned different costs of movement to landscape features. I created one or more resistance surfaces for each hypothesis of landscape effect. I used circuit theory to estimate the cumulative resistance between each pair of reserves for each weighting scheme, and then performed Mantel tests to calculate the correlation between these resistances and the observed population pairwise genetic distances (D[subscript hat]). I chose the optimal resistance model for each species as the model that was most highly correlated with observed genetic patterns. To verify that the correlation of resistance models with genetic distance was not an artefact of geographic distance, I performed partial Mantel tests to calculate correlation while controlling for the effect of geographic distance. Finally, I compared historical gene flow patterns to the distribution of contemporary human activity to predict areas that are at risk of a loss of connectivity. Indices of genetic diversity were moderate for all three species and comparable to previously reported values for other savannah ungulates. Diversity (both H[subscript E] and A[subscript R]) was highest in eland and lowest in giraffe for these populations, and was not consistently correlated with reserve size as has been reported for other species in East Africa. Although patterns in genetic distance were broadly similar across all three species there were also striking differences in connectivity, highlighting the importance of cross-species comparisons in connectivity conservation. At this scale, resistance models based on slope strongly predicted population structure for all three species; distance to water was also highly correlated with genetic distance in eland. For all three species, the greatest genetic distances occurred between populations separated by the Eastern Arc Mountains, suggesting that the topography of this area has long acted as a barrier to gene flow, but this effect is present in varying degrees for each species. I observed high levels of historical gene flow between centrally located populations (Ruaha National Park and Rungwa Game Reserve) and those in the southwest (Katavi National Park and Rukwa Game Reserve). Although human settlement in this area has been low relative to other areas, the connection between the Katavi/Rukwa and Ruaha ecosystems may be threatened by increased human activity and warrants conservation. High levels of historical gene flow were also seen between reserves in the northeast (Tarangire National Park, Swagaswaga Game Reserve) and the central and southwest populations. These connections appear highly threatened due to current land use practices, and may have already suffered a loss of gene flow. Field surveys in the lands surrounding the northeastern reserves are needed to quantify current levels of connectivity and determine whether corridors could be established to maintain or restore gene flow with other reserves. / Graduation date: 2012

Text in English / The purpose of this study was to establish the vulnerabilities of the security control measures that are being used at Impala Platinum mines and refinery to prevent the theft of Platinum Group Metals (PGMs). It is important to ensure that the security control measures in place are effective and efficient in preventing the occurrence of such theft. The research examined the security risk management approach to the prevention of theft of PGMs and the causes of theft of PGMs by organised crime syndicates operating in South Africa and abroad. The study found that Impala Platinum employees, in collusion with contractors and members of mine security services, are involved in the theft of PGMs. To achieve the goals and objective of the research study, effective security control measures were identified that will help Impala Platinum mines and refinery to overcome the risks and challenges related to the theft of PGMs. / Security Risk Management / M. Tech. (Security Management)