Abstract: The status of honeybee pathogens and parasites in the Gauteng region of South Africa was examined by collecting adult honeybee and worker brood samples from 13 Apis mellifera scutellata apiaries. The prevalence of pathogens and parasites were compared per season between sedentary (permanently stationed colonies) and migratory (transportation of colonies for pollination purposes) apiaries. Honeybee pathogens (Acute bee paralysis virus (ABPV), Black queen cell virus (BQCV), Chronic b...
Abstract: Tropical forests are shrinking worldwide. This is mainly because human beings, in a bid to obtain a livelihood, have overexploited their timber and non-timber products. At Arabuko Sokoke Forest (ASF), Kenya, community-driven conservation projects have been initiated, to ensure that the people can draw a livelihood from this vital ecosystem without destroying it. Among the projects involved is apiculture in the vicinity of the forest. Although some studies have been carried out on v...
Abstract: Southern elephant seals (Mirounga leonina) are relatively common top predators and major consumers within the Southern Ocean. This study aimed to describe the at-sea behaviour of a small population of southern elephant seals at Marion Island and to place this behaviour into an ecological and evolutionary context. Calculations of life-time habitat use for animals from this population revealed that seals spent an average of 77.59% of their lives diving at sea, 7.06% at the sea surfac...
Abstract: Read abstract in the document
Abstract: Please read the abstract in the section 00front of this document
Abstract: Conventional approaches to water management have traditionally treated social systems and ecosystems as distinct, and to a large degree have failed to achieve outcomes that are simultanously efficient, equitable, and sustainable. Perhaps nowhere has the need to reform the way water is managed and even conceived been more apparent than in South Africa in the last decade, where a tremendous opportunity for change has been created in the form of the National Water Act of 1998. In this...
Abstract: Please read the abstract in the 08summary part of this document
Abstract: Ungulate browsing and its ecological effects at plant, population, community, and ecosystem levels were addressed in a eutrophic southern African savanna. This was to test predictions of prevailing hypotheses, which are based on research in boreal and temperate forests. Changes in plant morpho-functional traits and population structure of a staple palatable species, Acacia nigrescens Miller were addressed over a two-year survey among vegetation stands with very different histories ...
Abstract: The pouched mouse, Saccostomus campestris Peters, 1846 from southern Africa shows a high degree of karyotypic variation where up to 16 variants (2n = 30–50) have been reported. This has led to a systematic uncertainty that the present study attempts to assess using: 1) cytochrome b (cyt b; 1077 bp) and 16S rRNA (528 bp) partial sequences; 2) G-banding cytogenetic data; and 3)geometric morphometric data of various views of the cranium and mandible. The results from these multidisc...
Abstract: Simulium chutteri is considered a major pest in South Africa and it has been estimated that it can potentially cause stock losses amounting to more than R88 million per annum. Although a larval control programme has been launched to control the pest, major outbreaks still occur, since major fitness traits such as longevity are ignored in the planning of control actions. To improve the control programme, the aim of this study was to study the longevity of S. chutteri females under v...
Abstract: Insects are considered to be responsible for 80-85% of all pollination, with honeybees being well known for their pollination services for many crops. The effect of managed honeybee pollination on sunflower seed yield and quality (germination percentage and oil content) was investigated at the University of Pretoria experimental farm and in commercial sunflower fields at Settlers. This was done through pollinator exclusion and pollinator surveys on sunflower field plots located at ...
Abstract: Southern Africa contains 58% of the world’s savannah elephant population, yet 72% of their range occurs outside of protected areas. It is, therefore, important to develop management guidelines that satisfy the needs of both elephants and people while maintaining environmental heterogeneity and ecosystem processes. Managing elephants as a metapopulation may provide the solution. The goal of this thesis was then to use a habitat-based approach to identify landscape characteristics ...
Abstract: No abstract available
Abstract: Killer whales are the oceans’ apex predator and are known to have important effects on ecosystems. At Subantarctic Marion Island, southern Indian Ocean, they have only been studied opportunistically, resulting in limited knowledge of their ecosystem impact here. This dissertation describes the prey and seasonal abundance, estimates the population size and assesses the predatory impact of killer whales on seals and penguins at Marion Island, using dedicated and opportunistic shore...
Abstract: This study provides the first quantitative analysis of the littoral and supralittoral arthropod assemblages of sub-Antarctic Marion Island. Seventeen mite species (126 203 individuals) from 11 families were found on the shore at Macaroni Bay. Three families dominated the assemblages in both abundance and diversity: the Hyadesiidae, Ameronothridae and Halacaridae. Six insect species from three orders were found on the shore. Species richness increased from one in the littoral, to fo...