Abstract: Please read the abstracts included at the beginning of chapters 2 to 5, of this document
Abstract: In this study, hypervariable region I (HVRI) of the mitochondrial DNA (mtDNA) control region, and five microsatellite loci were used to assess genetic variability and the extent of hybridization between the two fur seals (Arctocephalus tropicalis and A. gazella), that occur on Sub-Antarctic Marion Island. Both species were harvested during the 18th and 19th centuries, leading to a reduction in population size and the extinction of A. gazella at some localities. Whilst both species ...
Abstract: Data recorded from annual tagging and regular tag resightings of southern elephant seals at Marion Island, permitted the investigation of temporal variation in the terrestrial haulout cycle of this species, and estimation of participation levels in the little understood resting haulout phase, that could be related to age, sex, and sexual status. Primigravid females moulted later, and were less inclined to rest, than nulligravid females of the same age, but moulted earlier than matu...
Abstract: Please read the abstract on page 3. Copyright 1975, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Underwood, R 1975, Social behaviour of the Eland (Tayrotragus Oryx) on Loskop Dam Nature Reserve, MSc dissertation, University of Pretoria, Pretoria, ...
Abstract: Quantitative studies of complete soil arthropod communities are considered essential if a thorough understanding of the structure and dynamics of soil faunas, and their likely response to anthropogenic environmental change, is to be gained. In practice, however, high species richness and poor taxonomic knowledge for most systems often hampers the acquisition of such information. In consequence, many studies resort to the use of higher taxa or more qualitative data. Sub-Antarctic te...
Abstract: Invasive alien species are considered the second greatest threat to global biodiversity after habitat loss. South Africa is not immune from such threats and it is estimated that 10 million ha (8.28%) of land has been invaded to some extent by invasive alien species. Although South Africa has been invaded by several taxa, it is the effect of invasive trees and shrubs that has been environmentally and economically most damaging. The concerns raised due to the effects of biological in...
Abstract: Field data were collected and analysed on the feeding and spatial ecology of spotted hyaenas and brown hyaenas living in the Madikwe Game Reserve. Methods used to estimate the population of spotted and brown hyaenas include audio call-in surveys, photographic records and mark-resighting. The localized convex hull method was used on data collected from latrine surveys, radio-telemetry, sighting records, and camera-trapping to determine the spatial ecology of hyaenas in Madikwe. Faec...
Abstract: The house mouse (Mus musculus) was introduced to Marion Island by sealers in the early 1800’s and was found abundantly over the entire Island as early as 1818. Despite the abundance of this rodent, little information is known about the invasive house mouse from Marion Island with regards to its genetics and infectious disease potential. Therefore, this study aimed to determine the genetic diversity of the house mouse Mus musculus on Marion Island, as well as the prevalence of thr...
Abstract: Faecal analysis (n = 806 scats) was employed to examine the diet of the Subantarctic fur seal Arctocephalus tropicalis at Marion Island (46° 54’S, 37° 45’E) over a period of six years (April 2000 – March 2006). Identifiable prey remains (fish otoliths, cephalopod beaks) were extracted from the faeces and analyzed. The number of individuals of each prey group identified was determined, and the size of individuals was estimated by applying appropriate regression formulae to m...
Abstract: Life-history theory is based on the notion that resources are generally limited in nature, and that organisms have to allocate these resources amongst different physiological systems to maximise their survival and fitness. Therefore life-history traits such as maintenance, growth and fecundity are very often negatively associated with each other. Since the immune system plays a prominent role in fitness and survival of an organism it often features in life-history trade-offs partic...
Abstract: An analysis of the social behaviour of the roan antelope (Hippotraqus equinus equinus Desmarest, 1804) is presented in this thesis. The study commenced in A herd of 10 animals in an enclosure - 1,6 kilos square and simulating natural conditions - provided ideal opportunities for intensive study: Further observations were made on free-roaming herds in the main roan habitat of the Park i.e. the Lebombo flats north of the Letaba river, The basic discipline regulating the interactions ...
Abstract: Recent studies of heterothermy in free-ranging mammals have revealed that solar radiation is an important variable influencing torpor patterns. The interaction between solar radiation (SR) and arousal costs can be thought of as a continuum from passive increases in body temperature (Tb) (rewarming at a slower rate but energetically less costly), to supplementation of endogenous heat production (rewarming more rapidly but with costs similar to that in the absence of solar radiation)...
Abstract: Foraging forms the cornerstone of an animal’s life-history. An individual's foraging success shapes the demography and health of a population. Understanding key facets of maternal foraging behaviour are crucial to get a holistic picture of both regional and local environmental factors that drive foraging behaviour. This study aimed to measure the maternal foraging behaviour of a marine top predator, the Subantarctic fur seal (Arctocephalus tropicalis), from Marion Island (MI) ove...
Abstract: Ten Cape porcupines were radiotracked for one year in a savanna ecosystem at Nylsvley Nature Reserve, Transvaal, South Africa. Social organisation was characterised by family groups comprising a monogamous adult pair and immature offspring. Pair members usually shared the same burrow and utilised similar home range areas. Group size is probably determined by the time of offspring dispersal which is dependent upon population density and resource dispersion and abundance. Total home ...
Abstract: 4 Summary Seasonal metabolic adjustments and partitioning of evaporative water loss in Wahlberg’s epauletted fruit bat, Epomophorus wahlbergi Student: Ingrid A. Minnaar Supervisor: Prof. A. E. McKechnie Co-supervisors: Prof. N. C. Bennett, Prof. Christian T. Chimimba Department: Zoology and Entomology, University of Pretoria Degree: MSc: Zoology The capacity to thermoregulate over a wide range of TaS is critical for maintaining homeostasis in endotherms. Several aspects of the th...