Abstract: The diet of an animal plays a fundamental role in its ecology, and the consequence of a specific diet may be more pronounced in mammals with a specialised diet that are more reliant on a specific food type. This can have a dramatic effect on its activity patterns, home range size and the interaction with heterospecifics. Investigating the diet of specialist mammals and the subsequent effects it will have on their ecology is thus vital to the management and subsequent conservation o...
Abstract: Termites are ecosystem engineers with well documented functional roles in African savannas. However, how their importance changes across environmental gradients, such as rainfall and nutrition, is less understood. Using LiDAR data from the Carnegie Airborne Observatory, I mapped the distribution of termite mounds across an entire river catchment in the Kruger National Park, South Africa. Abiotic factors shaped mound densities at broader landscape scales, while local hillslope morph...
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: 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: 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...
Description: Thesis (PhD)--University of Pretoria, 2014.
Abstract: In most tropical river systems there has been a lack of integrated ecological research to investigate the dynamics and impacts of invasive species on recipient river systems. This is in sharp contrast to temperate river systems. This thesis investigated the nature, extent, and impact of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), on indigenous congenerics within the Limpopo River basin in northern South Africa. An integrated approach was adopted to gain a better understan...
Abstract: The migration of Southern Hemisphere humpback whales Megaptera novaeangliae between their feeding and breeding areas is considered a highly predictable and seasonal event. The west coast of Africa is host to Breeding Stock (BS) B, which has been divided into sub-stocks B1 and B2 based on different catch histories observed between Gabon in the north, and other stations to the south – a notion supported by recent regional genetic analysis, some samples of which were collected durin...
Abstract: Nectar-feeding birds must ingest copious amounts of water due to their liquid diet. Large volumes of preformed water in the dilute diet mean that birds feeding on these diets risk the loss of solutes in order to excrete this water. Previous studies have found that on dilute diets (
Abstract: African swine fever (ASF) is a highly contagious transboundary viral infection of domestic pigs that has serious socio-economic implications on people’s livelihood, international trade and food security. It is still a major limitation to profitable pig production and presently, it is threatening the pig industry internationally with current outbreaks in the Russian federation and the Caucasus. Since 1996, the disease has made major incursions into the West African sub-region. In ...
Abstract: This thesis addresses questions within the research fields of invasion biology and spatial ecology, with a focus on species distribution patterns, biogeographical regions and ecological transition zones, or ecotones. More specifically, species distribution patterns in alien plants at large spatial scales using atlas data, and invertebrate patterns making use of field data collected at a smaller scale (total extent ca. 30 km). First I show that alien plants form largescale geographi...
Abstract: The greater kudu (Tragelaphus strepsiceros) is a large spiral-horned antelope that occurs in sub-Saharan Africa. The species is predominantly a browser and inhabits a diverse range of habitats including savanna woodland, scrub and open forests. The geographical distribution extends from south-eastern Chad, northern Central African Republic (CAR), through eastern Africa, to southern Africa. Throughout its range the species is threatened by habitat loss, fragmentation, diseases and h...
Abstract: The general architecture of the skin of the southern right whale, Eubalaena australis, is comparable to that described for other cetacean species. As found in bowhead whales, Balaena mysticetus, of the same family, southern right whales possess an acanthotic epidermis and a notably thick hypodermis. Epidermal rods and extensive papillomatosis support these unique characteristics. A "fat-free" reticular dermis makes the integument of southern right whales more like that of odontocet...
Abstract: ENGLISH: This thesis is a study of the microstructure of hair of southern African mammals, in particular of the Carnivora. It serves to fill a gap in knowledge of hair studies from this region, and points to the use of these studies in various fields. A major portion of the work is a hair atlas of southern African Carnivora, in which micrographs and coloured plates of hairs are presented with locality data and a descriptive text for each species. Although the findings of the atlas ...