Abstract: Savanna elephants currently inhabit some of the hottest environments in Africa. Because of climate change, these environments are likely to get hotter. Due to their large body size and small body surface area to volume ratio, elephants may face difficulties in dissipating heat. Despite this suggestion, we do not understand how elephants in their natural environment respond to present day climatic extremes, which limits our ability to predict how elephants may respond to climate cha...
Description: Thesis (PhD)--University of Pretoria, 2014.
Abstract: Mating systems are classifications of the outcome of individual strategies aimed at maximising reproductive success. These systems have two components; one describes how individuals socially relate and bond to mating partners and the other describes the genetic outcome of actual mating activities. Reproductive activity is under strong endocrine and behavioural regulation where inter-sexual discrepancies in the regulation of reproductive success have resulted in the majority of mamm...
Abstract: Aspects of the ecology of B. monticularis were studied with a view to the species' conservation. This investigation indicates that the present distribution is half that of the past distribution and that only one third of the original habitat remains uncultivated. It is estimated that this area could, theoretically, support 1435 rabbits. The shrubs, Pteronia erythrocaetha and Kochia pubescens constitute the bulk of the species' diet; grasses are included in the diet whenever rainfal...
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: Dyer Island is thought to host one of the most abundant populations of white sharks on the planet; this is often credited to the large (55 – 60,000) Cape fur seal colony at Geyser Rock. Yet relatively little work has ever been produced from the area. This may be attributed to the harshness in its location as a study site, exposed to wind and swell from west to east which limits research periods. This study accounts for over 220 hrs of manual tracking at Dyer Island with a further...
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: The broad objective of the study is to examine mass change as related to other life history parameters of southern elephant seals Mirounga leonina at Marion Island. It has been argued that mass plays a fundamental role in their annual life cycle. This study investigates the reproductive investment and strategies of female southern elephant seals over a temporal scale using innovative sampling methods. Long term population studies are of great interest to life history studies as the...
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: Heaviside‟s dolphins, Cephalorhynchus heavisidii, are among the least known cetaceans. They are endemic to the coastal waters along the west coast of southern Africa. The occurrence, behaviour and group dynamics were investigated for these dolphins in Table Bay, South Africa during the summer of 2008 and 2009. Markrecapture photographic identification techniques, modelling techniques and Geographical Information System (GIS) were used to analyse the data. The dolphins were observ...
Abstract: No abstract available.
Abstract: Biodiversity perceptions of conservation managers in the North West Parks and Tourism Board are "teased out" to find how they view biodiversity issues in general and also how they perceive the functioning of their organisation. This report is the discussion and interpretation of responses to the questionnaire by managers at different ranks of the organisational structure. The results intend to show areas where the organisation is seen to be doing well and where it seen to be lackin...
Abstract: The mean dissociation constant (± SEM) of the uterine progesterone receptor for progesterone in eight rock hyraxes, culled at Elandsrand Mine Reserve, was 1.78 nM (±O.l07). The receptor also showed a high relative binding affinity (RBA) for the synthetic hormones norethindrone (%RBA = 185), levonorgestrel (%RBA = 179) and RU486 (%RBA = 221). The binding of norethindrone is similar to that of the African elephant and thus allows for the use of the hyrax as a biological model for t...