PhD Theses

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Browsing PhD Theses by Author "Mulamula, Lilian Gaspar"

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    Land Cover, Climate and River Flow Linkages and their implications on human wellbeing in lukuled river Catchment Area, Tanzania.
    (University of Dar es salaam, 2020) Mulamula, Lilian Gaspar
    This study assessed the variability and interplay between land cover change, climate and river flow variabilities and their implications on human wellbeing . The specific objectives of the study where: to examine the spatial and temporal land cover change in the lukuledi River catchment area: analyse rainfall and temperature trends and seasonal rainfall behaviors; evaluate the linkages of land cover change, climate and river flow variabilities and assess implication of the land cover change, climate river flow variabilities on community well-being. The model of human interaction with the environment andfrivers, pressure, state, impact and response model (DPSIR) were used to guide the study. Mixed method research design involving descriptive and analytical approaches was used. The Random Forest Classifier model was used for land cover classification. The time series data of rainfall and temperature were analyses for trends and step change. Analysis of seasonal rainfall behaviour and selected rainfall indices of importance to community wellbeing were also done. Trend and climPACT2 software were used for analysis of climate data. Soil and Water Assessment Tool (SWAT) model was used to investigate the linkage between land cover change, climate variability and river flow. Field survey data was used to understand implication of land cover change and observed hydro-climatic variability on community wellbeing. Results have shown that, land cover was dominated by bushland, forest and cultivated land characterized with transformation from forest to bushland and agricultural land. Human activities are at the centre of land cover change in Lukuledi River catchment area. Direct drivers of land cover change are agriculture, logging, charcoal making and collection of firewood and construction poles. The underlying factors for land cover change are rise in population, economic opportunities and forest and water conservation policies. The annual rainfall amount in the Lukuledi catchment is dominated by a decreasing trend with step changes seen in five out six stations. Temperature is increasing and has positive step changes. Seasonal rainfall behaviour is dominated by early onsets and late cessations. There is observed increase in number of raindays in three stations which is caused by an increase in consecutive number of wet days within the rain season and not increase in seasonal rainfall duration. Extreme rainfall exceeding 50mm was found to be increasing in two stations and decreasing in two. Both climate variability and land cover change cause a decrease in in mean annual flow of the Lukuledi River. Climate variability cause more impacts on the river flow than the land cover change. There is more discharge during dry season in land rich in vegetable cover as compared to the land with less vegetation cover. Agriculture is the key aspect linked with human wellbeing that is highly impacted by hydro-climate variabilities. Other areas affected are water for domestic and livestock use, water for biodiversity and access to forest resources. The study concludes that human environment interactions consist of strong feedback loops. Human activities have caused a disturbance on the functioning of the river catchment ecosystem. The resulting disturbed ecosystem goes back to affect the human wellbeing. These impacts are interlinked and exacerbating individual impacts. The study recommended promotion of farming practices that offer better optimization of the available agricultural land thus less conservation of natural vegetation diversification of livelihoods to reduce the impacts of climate variabilities, and awareness of the interlinkages of the factors so as to raise a conservation driver. For sustainability of the existing plans of expanding irrigation potential of the catchment, special emphasize should put in conservation of the catchment vegetation. Forest conservation initiatives should also put community needs in their priority so as to ensure a win-win situation between conservation of the forests and community needs.