Browsing by Author "Gumede, Silindile Thobeka."
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Diet preference of common mynas (Sturnus tristis) in urban areas of Pietermaritzburg and Durban, KwaZulu-Natal.(2017) Gumede, Silindile Thobeka.; Downs, Colleen Thelma.Urbanization is one of the anthropogenic land use changes with a negative impact on biodiversity generally. However, some species are persisting well in urban areas and are termed urban exploiters. One of these species is the common myna (Sturnus tristis). It is also considered amongst the 100 worst alien invasive birds globally. As relatively little is known about the factors that affect common mynas invasive ability and urban persistence, aspects of their diet were investigated. Consequently, the main aims of this project were to investigate the macronutrient preference, sugar type and concentration preference, and assimilation efficiency of captive common mynas in the laboratory from July 2016 to March 2017. In addition, patterns of occurrence of common mynas in urban areas of Pietermaritzburg and Durban, KwaZulu-Natal, South Africa, and the influence of supplementary feeding and anthropogenic foods on their diet were investigated using questionnaires. Common mynas (n = 10) macronutrient preference was investigated in the laboratory where they were offered pairwise choices of three different diets (high in lipids diet, high in soluble carbohydrates (including sucrose) diet, and high in protein diet). Common mynas significantly preferred the high in lipids diet compared with either the high in protein diet or the high in carbohydrate diets. Common mynas (n = 7) were offered pairwise choices of three nectars (glucose, fructose and sucrose) to investigate their sugar type and concentration preference. Birds showed a significant preference for diluted glucose when given a choice of nectars. The sugar content of their excreta showed that they were unable to digest and absorb sucrose in nectar. Responses from the questionnaires showed that common mynas were found in the two study cities and were abundant year around. Results also showed that they were feeding mostly on anthropogenic foods compared with natural foods. Anthropogenic supplementary feeding has likely influenced the occurrence of common mynas because they follow food resources (human food waste) in urban areas and therefore successfully persist through lean periods. Further research is needed to help understand the ecology and behaviour of common mynas in order to get insights on how to monitor and control them in urban areas, in particular in South Africa where their range is expanding. Common mynas behaviour is currently poorly documented in South Africa. Since these are alien invasive birds with negative impacts in other countries, more research, especially on their behaviour, is required to prevent their negative impacts occurring in South Africa.Item Taxonomic, functional, and avian community dynamics in selected Southern Mistbelt Forests of southern KwaZulu-Natal and the Eastern Cape, South Africa.(2020) Gumede, Silindile Thobeka.; Downs, Colleen Thelma.; Ehlers Smith, David Alan.; Ehlers Smith, Yvette Cathrine.Human population increase and landscape transformation result in the reduction of natural habitats, such as forests, causing changes in forest patch composition, habitat amount, patch size, isolation, shape, and edges. This is challenging specialist such as Orange Ground-thrush (Geokichla gurneyi) and Lemon Dove (Aplopelia larvata) species unable to survive in fragmented habitats and also influencing the composition and distribution of avian species assemblages. Therefore, the main aims of this multifaceted study were to (1) assess the habitat requirements of two forest specialised bird species, the Orange Ground-thrush (Geokichla gurneyi) and the Lemon Dove (Aplopelia larvata); (2) identify if avian assemblage diversity and species functional trait diversity show consist patterning across different landscapes in a forest ecosystem; (3) determine the influence of vegetation structures on the taxonomic and functional diversity of avian forest species, and (4) modelling how to connect forest patches of higher functional diversity. In 2018-2019, we conducted a series of camera-trap surveys of 21- day periods and fixed-radius point-count surveys at 420 sites across 94 forest patches of Southern Mistbelt Forest of southern KwaZulu-Natal and Eastern Cape, South Africa, during the breeding and non-breeding seasons in conjunction with surveys of microhabitat structural covariates. Firstly, we modelled the probability of occupancy and detection for the selected two species, which showed that forest specialist species prefer a highly diverse habitat structure. Secondly, we quantified functional diversity measures based on species’ trait per patch to measure the influence of habitat and landscape configuration on each measure. This resulted in functional diversity measures which were highly influenced by patch size, the distance between patches and diverse landscape and habitat. Thirdly, we conducted RLQ analyses to examine the association between avian functional traits and microhabitat structures present at each forest patch.We found there was a significant difference in vegetation structure and species richness between forest patches. Lastly, we ranked the functional diversity measures scores of avian communities present at each forest patch to identify core habitat patches responsible for the contribution of high functional diversity measures. Protection of natural forest habitat and diverse landscapes is important in preserving avian communities.