Abstract: A number of daily rhythms were investigated under different lighting conditions and the topographical arrangements of visual (rods/cones) and non-visual retinal photoreceptors (ipRGCs) determined, in the Namaqua rock mouse (Micaelamys namaquensis) and the four striped field mouse (Rhabdomys pumilio). The present study provides evidence that M. namaquensis possesses a distinctly nocturnal locomotor activity rhythm that is endogenously entrained by the light-dark cycle, with a near 2...
Abstract: Genetic parameters such as genetic variability, gene flow, relatedness and migration were determined between two South African coastal delphinid species, Cephalorhynchus heavisidii (Heaviside’s dolphin) and Tursiops aduncus (Indo-Pacific Bottlenose dolphin), in order to contribute towards designing efficient conservation management strategies. The molecular markers used in this study include the mitochondrial DNA control region (mtDNA) and several microsatellite loci that were ch...
Abstract: Phylogeographic patterns as well as divergence date estimates and the past population demography of Hemachatus haemachatus were analysed using nuclear and mitochondrial genetic markers. My results suggest that H. haemachatus forms a continuous population that diverged into two broad lineages due to glacial and interglacial cycles during the Plio-Pleistocene interval. During this interval, stable populations existed in the southern Cape and eastern inland regions of southern Africa....
Abstract: Oribi antelope (Ourebia ourebi), South Africa’s most endangered antelope species, are predominantly found on privately-owned lands. As such, the implementation of conservation strategies on these lands is essential if the species is to avoid extinction in South Africa. In order to develop effective private land conservation strategies for oribi, it is necessary to go beyond the ecology of the species and possess an understanding of private landowners’ attitudes towards and know...
Abstract: Many aspects of animal digestive form and function vary with ecological factors including diet composition and food availability. I examined phenotypic flexibility of digestive traits in white-browed sparrow-weavers (Plocepasser mahali), a widespread southern African passerine in which the ratio of insects to plant matter consumed varies seasonally. I predicted that digestive traits of P. mahali are modulated in response to diet composition. For experiment one, I caught forty-five ...
Abstract: The Western Cape is a unique area to undertake research, due to the varying oceanographic conditions along the coast. These diverse environments create a hotspot for cetacean presence and diversity. This study aimed to collate and map distribution information of local whale and dolphin species in the Western Cape using citizen science. The first data chapter focused on obtaining opportunistic sightings from water users from scientific, platform of opportunity and sporadic sighting ...
Abstract: The fragmentation and loss of natural habitats brings about species losses. These losses may be amplified or reduced by the composition of the habitats surrounding remnant habitat fragments, i.e the matrix. The influence of the matrix on biological assemblages is, however, complex and poorly understood. Therefore, in this dissertation, I aim to determine whether matrix transformation influences bird assemblages within remnant natural habitat fragments and how patterns of bird diver...
Abstract: The southern tip of South Africa is characterised by two major current systems, each of which is associated with its own species. The southwest coastal waters represent the limit of the local or global distribution ranges of four of the eight cetacean species that most frequently occur in the area. The goal of the present study was to determine the fine scale distribution of these species and subsequently investigate which environmental factors influence and possibly limit their cu...
Abstract: Beta diversity, defined as the variation or turnover in species composition, is important to the understanding of how ecological communities assemble. Studies of beta diversity during secondary forest succession may thus afford the chance to understand community assembly from a known onset. This study examined the relationship between regeneration age and beta diversity within and between seral stages along a coastal dune forest successional sere for three taxa (trees, millipedes, ...
Abstract: Globally emphasis has been given to identify emerging and re-emerging pathogens. Rapid urban expansion creates a problem which is two-fold. Firstly, increasing slum living conditions due to inadequate rate of infrastructure development results in an increased reliance on natural resources, including the capture and consumption of surrounding wildlife to subsist, thereby facilitating the transfer of emergent zoonotic pathogens. Secondly, through activities such as pollution or alien...
Abstract: With catches of over 360,000 individuals, Antarctic blue whales Balaenoptera musculus intermedia were harvested to near extinction by commercial whaling in the past century. Antarctic blue whales are an important ecological component of marine ecosystems as they ensure the circulation of nutrients in the pelagic environment making such nutrients accessible for primary production. However, their recoveries; distributions; migrations; large-scale response to environmental variabiliti...
Abstract: Groups of translocated orphaned juvenile African elephants were studied in holding pens and following their release to assess how they re-organize and restructure socially by adopting roles, and if they show behavioural signs of stress. An adult female adopted a young individual. In all groups allomothering was observed to some degree. One 5 year old female prematurely assumed the role of leader and this role appears to be learned. Most groups established a linear dominance hierarc...
Abstract: This study was carried out in the eastern Transvaal Lowveld in an area 2 with a giraffe population density of 2,6 per km . Lions are the only predators and it was estimated that 48% of the calves die in their first year. The sex ratio departs significantly from unity in favour of females. Plant fragments in the rumen were identified. Giraffe subsist on the leaves of trees and shrubs, though fruit, flowers, twigs and grass were also utilised. Marked seasonal changes in the plant spe...
Abstract: Climate change is leading to loss of global and local biodiversity through changes in the ecology of fauna and flora. Changes in environmental temperature influence species distributional ranges. They respond by either migrating along with the shift in ecological zones or adapting to the new environmental conditions within a habitat. If neither adaptation nor migration is possible, local extinction of the species can result. This study was performed at Mariepskop mountain which ser...
Abstract: This thesis reports the findings of a fine-scale habitat selection study of Heaviside s dolphins (Cephalorhynchus heavisidii) at two sites in Namibia; Walvis Bay and Lüderitz. Walvis Bay and Lüderitz are the two largest embayments along the Namibian Coast, and therefore the two industrial ports in Namibia are located there. These bays are also inhabited year-round by Heaviside s dolphins, and, at Walvis Bay, a resident population of common bottlenose dolphins (Tursiops truncatus)...