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: Please read the abstract in the section 00front of this document
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: In group living species animals commonly compete for limited resources such as food (Darwin 1859). Winning competition for food may be beneficial for an individuals survival or reproductive success (Williams 1966; Clutton-Brock 1988; Metcalfe et al 1995) but conflict with group members may be costly as it typically involves aggression (Huntingford&Turner 1987, Mesterton-Gibbons&Adams 1998). Asymmetries between individuals are predicted to determine the outcome of competition (Mayna...
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: The southern African species of the Aradidae subfamily Carventinae are revised, resuhing in the recognition of 7 genera, 24 species and 10 subspecies (excluding the nominal ones). Of these, 4 genera, 18 species and 10 subspecies are described as new. A neotype is designated for Dundocoris natalensis. Keys to the genera and species are given. Scanning electron photomicrographs of the dorsal and ventral aspects and external genitalia are provided for all the species. The cytogenetics...
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 study set out to determine some of the bioecological relationships of the sable antelope Hippotragus niger niger (Harris, 1838) in the Rhodes Matopos National Park, Rhodesia. The vegetation of the area is divided into seven categories each of which is discussed. The population in the study area (approximately 200) had three major components as follows: the breeding groups, the bachelor male groups and territorial males. The structure of the breeding groups varied seasonally. Ba...
Abstract: The African bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a polyphagous pest that attacks many crops in sub-Saharan Africa. The pest is currently managed through chemical control, and by planting Bt-transgenic cotton. Trichogrammatoidea lutea Girault (Hymenoptera: Trichogrammatidae) is an indigenous egg parasitoid of H. armigera in southern Africa. The study was undertaken to determine the potential of T. lutea as a biological control agent for augmentative ...
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...
Abstract: A holistic evolutionary approach is used in the Gorongosa thesis in which emphasis is on the salient reciprocal relations and kinetic succession of land surfaces and biotic communities, influenced by landscape processes and prime mover components. As correlations of these relations and processes require both a total interacting framework and the details of its prime components, the thesis is divided into three main parts: (1) synopsis of the essence of the Gorongosa ecosystem and t...
Abstract: Please read the abstract in the section 08summary of this document
Abstract: Bats inhabiting arid, subtropical environments face diverse challenges related to energy and water balance. First, they may have to conserve water and energy during cool, dry winters when water is scarce and insect availability reduced. Second, during hot summers when air temperature may routinely exceed body temperature, bats may need to avoid both hyperthermia and dehydration. A common response to the energetically challenging winter period in temperate, subtropical and tropical ...
Abstract: In this thesis, I investigated the relationship between host and pathogen in multi-host and multi-pathogen systems at the interface between wildlife and domestic species. The term “epidemiological interaction” was central to my thesis, and was defined as “any ecological interaction between two host populations resulting in the transmission of one or more pathogen”. Epidemiological interactions are related to the processes of transmission between hosts and I investigated how...