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Masters Degrees (Biological Sciences)

Permanent URI for this collectionhttps://hdl.handle.net/10413/12380

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Browsing Masters Degrees (Biological Sciences) by Author "Downs, Colleen Thelma."

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    Assessment of roadkills in Hluhluwe-Imfolozi Park, KwaZulu-Natal, South Africa.
    (2017) Mkhohlwa, Muzi Nicholas.; Downs, Colleen Thelma.
    Anthropogenic land-use activities are considered to be the main contributor to current worldwide changes in natural ecosystems. South Africa is one of the countries that has been severely affected by changing land-use. The changes in land-use in South Africa are driven primarily by the need to provide food, water, and shelter to a growing human population and for economic growth. However, consequences of such actions impact biodiversity negatively with effects that lead to habitat fragmentation, loss of wildlife habitats, wildlife mortalities and species declines. One factor that contributes negatively is the increased number of roads and associated traffic. This study was conducted in Hluhluwe-Imfolozi Park (HIP), KwaZulu-Natal, South Africa, to assess roadkills on roads of the park. We conducted monthly roadkill surveys on three main roads (R618 corridor road traversing the HIP, paved road from Memorial Gate to Hilltop Resort, and an unpaved road from Memorial Gate to Isivivaneni Lookout) within HIP for a year. Furthermore, we assessed the public’s level of awareness about roadkills using questionnaire surveys. Relatively few roadkills were reported in our study when compared with other studies. The taxa that were reported as roadkills included mammals, birds, reptiles and amphibians. The R618 corridor road traversing the HIP had the highest number of roadkills, followed by the paved road then the unpaved road within park. Factors that contributed to reported roadkills were season, type of road, amount of game in the vicinity, and the distance to roadside vegetation from the road. In addition, the public showed limited awareness about roadkills occurring in HIP, but were aware of how they were expected to drive within protected area road networks. Mitigation measures such as mowing, signage, enforcement of harsh laws and introduction of fines were recommended as means that would help in the reduction of roadkills in HIP.
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    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.