Browsing by Author "Nnko, Happiness Jackson"

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    Impacts of anthropogenic and climate variation on spatiotemporal pattern of water resources: A case study of Lake Babati, Tanzania
    (Springer, 2020) Peter, Kalista Higini; Nnko, Happiness Jackson; Mubako, Stanley
    Water resources such as lakes are important for sustaining human life and aquatic ecosystems, but a lack of understanding of pressures from anthropogenic activities and recurring floods and droughts can cause problems for communities and ecosystems because of their impact on lake size and water quality. This study aims to assess the impacts of anthropogenic and climate variation on the spatiotemporal pattern of Lake Babati in Tanzania by establishing physical trends over a period of more than four decades, and evaluate how land use/cover change and climatic variation influenced the pattern. The assessment was made using Landsat images acquired from the United States Geological Survey for the years 1973, 1986, 1991, 1995, 2000, 2005, 2010, 2015, and 2018; daily precipitation and temperature data spanning 1973–2018 sourced from the African Flood and Drought Monitor database, and augmented by field surveys of anthropogenic activities around Lake Babati Basin. Findings from this study revealed a fluctuation of lake surface area between 10.90 and 14.19 km2 over 45 years, partly attributed to rapid urbanization, agriculture and climate variation around the lake. The largest lake areal extent decrease of 2.72 km2 and largest increase of 3.29 km2 were experienced between 2000 and 2005 and 1995–2000, respectively. Enhanced understanding of lake size trends from these results and associated environmental threats can guide the implementation of community programs in the Lake Babati Basin. We recommend water resource management policy options that include awareness raising, diversification of income generating activities and enforcement of environmental laws.
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    Potential impacts of climate change on geographical distribution of three primary vectors of African Trypanosomiasis in Tanzania's Maasai Steppe: G. m. morsitans, G. pallidipes and G. swynnertoni
    (National Library of Medicine (NLM), 2021) Nnko, Happiness Jackson; Ngonyoka, Anibariki; Gwakisa, Paul Simon; Sindato, Calvin; Estes, Anna Bond
    In the Maasai Steppe, public health and economy are threatened by African Trypanosomiasis, a debilitating and fatal disease to livestock (African Animal Trypanosomiasis -AAT) and humans (Human African Trypanosomiasis-HAT), if not treated. The tsetse fly is the primary vector for both HAT and AAT and climate is an important predictor of their occurrence and the parasites they carry. While understanding tsetse fly distribution is essential for informing vector and disease control strategies, existing distribution maps are old and were based on coarse spatial resolution data, consequently, inaccurately representing vector and disease dynamics necessary to design and implement fit-for-purpose mitigation strategies. Also, the assertion that climate change is altering tsetse fly distribution in Tanzania lacks empirical evidence. Despite tsetse flies posing public health risks and economic hardship, no study has modelled their distributions at a scale needed for local planning. This study used MaxEnt species distribution modelling (SDM) and ecological niche modeling tools to predict potential distribution of three tsetse fly species in Tanzania's Maasai Steppe from current climate information, and project their distributions to midcentury climatic conditions under representative concentration pathways (RCP) 4.5 scenarios. Current climate results predicted that G. m. morsitans, G. pallidipes and G swynnertoni cover 19,225 km2, 7,113 km2 and 32,335 km2 and future prediction indicated that by the year 2050, the habitable area may decrease by up to 23.13%, 12.9% and 22.8% of current habitable area, respectively. This information can serve as a useful predictor of potential HAT and AAT hotspots and inform surveillance strategies. Distribution maps generated by this study can be useful in guiding tsetse fly control managers, and health, livestock and wildlife officers when setting surveys and surveillance programs. The maps can also inform protected area managers of potential encroachment into the protected areas (PAs) due to shrinkage of tsetse fly habitats outside PAs.