Abstract: The small size of nectarivorous birds is associated with high mass-specific metabolic rates and energetic lifestyles. Their energy balance is likely to be strongly influenced by environmental factors. Firstly, nectar varies in sugar concentration between different food plants and birds must adjust their consumption to maintain a constant energy intake. Secondly, unfavourable weather conditions, such as storms and heavy rains, may prevent birds from feeding, and they must increase t...
Abstract: Clearly established conservation priorities are urgently required for taxa and ecosystems in critical need of conservation. This helps to identify and document taxa most in need of conservation attention, and provides an index of the state of degeneration of biodiversity. Including as much relevant information as possible in a prioritisation assessment will deliver the most accurate classification, yet these variables should not overly complicate the prioritisation process. Conserv...
Abstract: The restricted geographic range and tenuous conservation status of wild dogs in South Africa were the motivating factors behind this study. Wild dogs have been extirpated from most of their historic range in South Africa, and now occur in three limited distributions: a) one viable population in Kruger National Park; b) a protected meta-population, consisting of 1 packs in six sub-populations (four on state owned reserves – Hluhluwe-Umfolozi Park, Madikwe Game Reserve, Marakele Na...
Abstract: Methods used to estimate the prey consumption by large carnivores include direct continuous observation, stomach content analysis, carcass observations and scat analysis. Continual observations are widely considered the best approach to estimate large carnivore diets, with lions (Panthera leo) being no exception. Continual observation allows the recording of all prey encounters and biases inherent in the other approaches are minimised. However, continuous observations are not alway...
Abstract: The ecologically sensitive, but relatively simple sub-Antarctic mouse-colonised Marion and mouse-free Prince Edward Islands represent ideal ecosystems for addressing questions relating to the partitioning of potential influences of anthropogenic changes, such as climate change and alien species on ecosystem functioning. Consequently, weevil species were used in the present investigation to address questions of morphological change over time with reference to climate change and mous...
Abstract: Xylose is an unusual nectar sugar found in the nectar of Protea and Faurea (Proteaceae). Since nectar composition is an important floral characteristic in plant strategies for ensuring reproductive success, the unexplained presence of xylose in Protea nectar prompted this study of the interaction between pollinators and Protea species. Among pollinators that visit Proteaflowers in the south-western Cape Floral Kingdom, South Africa, insects and birds show an aversion to, and are po...
Abstract: Genetic variation, structure and dispersal among Cape buffalo populations from the Hluhluwe-Imfolozi and Kruger National Parks of South Africa Barend Jacobus (Ben) Greyling Doctor of Philosophy (Zoology) Department of Zoology and Entomology Supervisor: Prof. Armanda Slager-Bastos Co-supervisor: Dr. Pim van Hooft 2007 The research reported on in this thesis is aimed at quantifying and qualifying, using a molecular genetics approach, some of the factors that influence the population ...
Abstract: Instability characterizes the taxonomy of the African rodent subfamily Otomyinae. Two genera, Otomys and Parotomys, and 14 species are currently recognized, but the generic subdivision is equivocal. Between two and five cytotypes are delimited within O. irroratus, which illustrate a rapid rate of karyotypic evolution, and may reflect incipient speciation. In an attempt to resolve the group's phylogeny, the mitochondrial cyt b (complete) and 12S rRNA (802 bp) genes were analyzed usi...
Abstract: The demography of two elephant seal populations was examined and compared. This was done to investigate the reasons for the observed decreases in populations at Marion and Macquarie islands. While a well-established demographic programme had been in place at Marion Island since the 1980's (see Pistorius et al. (l999a) for a review) one had to be established at Macquarie Island. A long-term demographic programme was initiated at Macquarie Island in 1993 and hot brands were used to m...
Abstract: Please read the abstract in the section 00front of this document. Please note that pages 9 and 10 are missing from the available paper, as well as the microfiche copy.
Abstract: African mole-rats (Bathyergidae) are subterranean hystricomorph rodents offering an excellent system with which to test theories relating to the evolution and maintenance of sociality in mammals. The aridity food distribution hypothesis (AFDH) suggests that, within the bathyergids, sociality has evolved in response to patterns of rainfall, its effects on food distribution, and the subsequent costs and risks of foraging and dispersal. Here, in the first detailed study of burrow arch...
Abstract: Ecological restoration has the potential to stem the tide of habitat loss, fragmentation and transformation that are the main threats to global biological diversity and ecosystem services. Through this thesis, I aimed to evaluate the ecological consequences of a 33 year old rehabilitation programme for coastal dune forest conservation. The mining company Richards Bay Minerals (RBM) initiated what is now the longest running rehabilitation programme in South Africa in 1977. Managemen...
Abstract: Southern right whale vocalisations recorded in Walker Bay, South Africa, between June and November 1999, were analysed to investigate the acoustic repertoire, the relationship between calling behaviour and whale presence, the proportions of vocal and silent whales, and of recorded calls from unseen whales, and the evidence for vocal individuality. This marks the first study of right whale vocalisation in South African waters. A simple matrix system with the axes acoustic contour an...
Abstract: The social reproductive inhibition evident in female common (Cryptomys hottentotus hottentotus) and highveld (Cryptomys hottentotus pretoriae) mole-rats was investigated, focussing on intra- and inter-subspecies differences in gonadotropin¬releasing hormone (GnRH) neuroanatomy and neuroendocrinology and potential mechanisms mediating social infertility through the suppression of luteinizing hormone (LH) and/or GnRH synthesis or release. The molecular structure of the GnRH peptide ...
Abstract: People and elephants share landscapes throughout Mozambique. Here elephant conservation management focuses on protected areas but fails to address the conflict that exists between elephants and people. In this thesis I develop a landscape approach to conflict mitigation that is designed to accommodate the needs of people and of elephants in human-dominated landscapes. Mozambique faces a dilemma: politically it is required to reduce poverty while at the same time adhere to internati...