Environmental & Physical Sciences

Research Papers/Topics Environmental & Physical Sciences

Restoration and ant diversity to post-plantation forestry grasslands

Abstract: There has been a widespread assessment of the capacity of grasslands to restore after several forms of disturbance. In South Africa forestry is a significant habitat disturbance within the Eastern Highveld grasslands where this study was conducted. The study compared ant communities between disturbed grasslands that have been rehabilitated after pine forestry and undisturbed grasslands. Ant sampling was conducted using pitfall traps within rehabilitated sites of age 10 years to 40 ...

Visual and olfactory cues used in host location by the blister beetle Hycleus apicicornis (Coleoptera: Meloidae), a pest of Desmodium (Fabaceae) species

Abstract: Desmodium spp. are leguminous plants mainly used as livestock fodder. In Kenya and neighbouring countries they are also used in a „push-pull‟ strategy by smallholder farmers to protect maize (Zea mays) against two major groups of pests, stemborers (Lepidoptera) and witchweed, Striga spp., by repelling the former away from the cereal crop and suppressing growth of the latter. However, smallholder seed production of Desmodium spp. is compromised by blister beetles Hycleus spp. (C...

The relative performance of surrogate measures for viable populations

Abstract: Please read the abstract in the section 00front of this document

The effect of habit edges on the rehabilitation of coastal dune community structure

Abstract: Please read the abstract before the references of this document.

Heterogeneity of dung beetle (Coleoptera: Scarabaeidae) assemblages in northern KwaZulu-Natal, South Africa: conservation implications

Abstract: Investigating the extent of local scale heterogeneity in assemblages is necessary to achieve a sound understanding of the processes giving rise to local assemblage patterns and the variation between them. Moreover, a clear understanding of local scale heterogeneity of assemblages is imperative in the development of effective regional conservation strategies. Previous studies examined the local scale heterogeneity in dung beetle assemblages between mixed woodland and sand forest hab...

The relative importance of natural and human-induced environmental conditions for species richness distribution patterns in South Africa

Abstract: I studied the spatial distribution of South African avian species richness from the viewpoint that humans are a substantial modifying force on earth, and have also modified the historical spatial distribution of species richness. The main aim of the thesis is to investigate the way in which humans have modified avian species richness patterns in South Africa at the quarter-degree square (QDS) resolution, which is a phenomenon that has been either overlooked, or not completely clari...

Implications of global change for important bird areas in South Africa

Abstract: The Important Bird Areas (IBAs) network of BirdLife International aims to identify sites that are essential for the long-term conservation of the world’s avifauna. A number of global change events have the potential to negatively affect, either directly or indirectly, most bird species, biodiversity in general and associated ecological processes in these areas identified as IBAs. To assist conservation decisions, I assessed a suite of ten landscape scale anthropogenic pressures t...

Regulation of protein and carbohydrate intake in caged honeybees Apis mellifera scutellata : assessment based on consumption and various performance measures

Abstract: When provided with the opportunity to select their diet, most insect herbivores regulate their nutrient intake. However, in a nutritionally heterogeneous environment and with changing demands for growth, development and reproduction, obtaining the required amount and balance of nutrients is a challenge. This is especially true for social insects where the workers bring food into the colony to be shared by nestmates. The ability of insects to self-select their diet is an important t...

Structure and function of a Lepidoptera assemblage in a human-influenced environment

Abstract: Please read the abstract in the front section of this document

Behavioural response of honeybees (Apis mellifera scutellata Lep.) to wild pollinators on sunflowers (Helianthus annuus L.)

Abstract: Pollination is an essential ecosystem service, increasing reproductive success of many crops, which can be provided by managed pollinators, wild bees (including honeybees) and other insect pollinators. However, the pollination services and the economic value of wild pollinators are often underestimated. Better understanding of the factors that influence honeybee foraging behaviour and pollination efficiency can contribute to the improvement of management practices that aim to enhan...

Homeostasis : humidity and water relations in honeybee colonies (Apis mellifera)

Abstract: One of the benefits of colonial living in insect societies is the ability to build a nest which enables the maintenance of a homeostatic microenvironment. The detrimental and uncertain effects of fluctuating ambient conditions are thus avoided. An extensive amount of work has documented the regulation of respiratory gases and temperature by honeybee (Apis mellifera) colonies but relatively little is known of their water relations. Nest humidity influences the fitness of the honeybe...


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