Abstract: Habitat loss and fragmentation drives the current extinction crisis. The processes through which it affects biodiversity, however, are complex and poorly understood. This is especially true for spatially complex regions that comprise a mosaic of land-use types, which often range from protected areas to dense human settlements. In such human-modified landscapes, it is important to determine the extent and impact of changing land-use patterns on biodiversity if we are to meet conserv...
Abstract: Since the energy available to an animal for cell growth, thermoregulation, reproduction and other physiological functions is highly dependent on seasonal environmental changes many small mammals breed seasonally during times when environmental conditions are most favourable for growth and survival of the young. In the tropics and sub-tropics, seasonal rainfall appears to be the main reason for seasonal breeding. In order to maximize fitness, it is important for an animal to be able...
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...
Description: Thesis (PhD)--University of Pretoria, 1992.
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: Earlier studies investigated the genetic structure of fragmented or isolated elephant populations by comparing the genetic characteristics of pre-defined populations. This study aimed to determine if there was genetic evidence for spatial structuring in a continuous elephant population in the Kavango-Zambezi Transfrontier Conservation Area (KAZA-TFCA). I sequenced one mtDNA gene region for 88 individuals and genotyped 100 individuals for 10 nuclear microsatellite loci. Bayesian Clu...
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...
Abstract: Read abstract in the document
Abstract: Prior to this in-depth phytosociological classification and biogeographical study, the only other intense floristic study focussing on all plant species done specifically on Mariepskop was the work by Van der Schijff and Schoonraad (1971 The aims of the study were to: (1) describe and map the plant communities above 1800m at Mariepskop; (2) analyse the life forms in each community using Raunkiaer’s (1934) classification as modified by Mueller-Dombois and Ellenberg (1974) in order...
Abstract: This thesis investigates a number of aspects of the biology of the East African root rat, Tachyoryctes splendens (Rüppell, 1835) and provides important information currently depauperate in the literature. These aspects include the general burrow architecture with respect to fractal dimension (i.e. exploration efficiency), locomotory activity patterns in relation to specific light cycles, the pattern of reproduction, age structure and population growth characteristics based on cran...
Abstract: Craniometrics is a very reliable and effective tool for studying the difference in animal morphology. Previously, traditional craniometrics were conducted with the aid of calipers in two dimensional format (2D). Such discounting of actual three-dimensional 3D form may result in loss of some relevant and critical information leading to compromised and unreliable results for studies such as population variation analysis of morphology. The employment of 3D photogrammetry allows a clos...
Abstract: There are many factors which may influence the distribution of parasites and often parasites are not evenly distributed amongst their hosts. The development and survival of ectoparasites is usually dependent on abiotic factors such as temperature and rainfall. Therefore differences in ectoparasite load between host populations and seasonal fluctuations in abundance are often found to be associated with climatic variations. However, biotic (host-related) factors have also been found...
Abstract: The study investigated the origin and diversity of the three matrilineally-defined invasive, commensal Rattus species, namely R. norvegicus, R. rattus and R. tanezumi known to occur in South Africa after routine identification of the species using molecular techniques. Subsequently, their role as potential zoonotic disease reservoirs in primarily urban environments with particular interest in their potential to transmit and spread zoonotic disease through direct contact as well as ...
Abstract: The roles of phylogeny and body size in avian heat stress physiology, and how they interact to set the upper limits to heat dissipation capacity, are largely unexplored. Determining thermal end points and maximum capacity for evaporative heat dissipation in species from diverse ecological guilds and evolutionary clades is vital for understanding species-specific vulnerability to future climatic scenarios. I measured evaporative water loss (EWL), resting metabolic rate (RMR) and bod...