Browsing by Author "Deckers, Jozef"

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    Economics of Grass Strips Used as Sediment Filters in the Riparian Zones of Lake Victoria, Uganda
    (Agroecology and Sustainable Food Systems, 2012) Mugonola, Basil; Kimaro, Didas; Isabirye, Moses; Deckers, Jozef; Poesen, Jean; Wanyama, Joshua; Mathijs, Erik
    Land-use change in the riparian zones has lead to flow of sediments and nutrients into Lake Victoria. Using net present value (NPV) and sensitivity analysis techniques, economic viability of Paspalum, lemon, and elephant grasses as sediment filters under maize production are determined. Findings reveal that grass strips in maize production generates NPVs of 1,620 Cha−1, 1,736 Cha−1, and 1,766 Cha−1 for maize + Paspalum, maize + lemon and maize + elephant grass, respectively, at 5% discount rate. Sensitivity analyses show, NPVs are stable to varying discount rates but not to yield declines in maize and grasses. Overall, integrated land use to reduce sediment and nutrient fluxes is a more acceptable solution to land-constrained farmers.
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    The impact of papyrus wetland encroachment on the spatial and temporal variability of stream flow and sediment export in the upper Rwizi catchment, Southwest Uganda
    (EGU General Assembly, 2014) Ryken, Nick; Vanmaercke, Matthias; Wanyama, Joshua; Deckers, Jozef; Isabirye, Moses; Poesen, Jean
    During the past 30 years, human activities in the Lake Victoria basin are responsible for eutrophication of Lake Victoria via sediment-bound nutrients. This affects food security for millions on people. Addressing this problem in this densely populated region will require adequate catchment management strategies. However, sediment yield and runoff data to develop such a strategy are currently unavailable. Also in general, sediment yields for catchments in tropical environments are very scarce, especially in East-Africa. Therefore, runoff discharge and sediment export measurements were conducted in the upper Rwizi, a representative catchment for the Lake Victoria basin which is located in Southwest Uganda. Land use in this catchment is characterized by grazing area on the high plateaus, banana cropping on the slopes and Cyperus papyrus L. wetlands in the river valleys. These papyrus wetlands are currently encroached and transformed into cropland. Eight subcatchments (99 km2 - 2120 km2), with different degrees of wetland encroachment, were monitored during the hydrological year June 2009 - May 2010.
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    Stakeholders’ Perceptions of the Problem of Wetland Degradation in the Ugandan Lake Victoria Basin Uganda
    (Natural Resources, 2020) Were Nakiyemba, Alice; Isabirye, Moses; Poesen, Jean; Deckers, Jozef; Mathijs, Erik
    Wetlands are one of the most essential resources of Uganda. They are key components of the riparian areas filtering sediments from run-off thereby reducing water pollution. However, they are increasingly threatened by the expansion of agricultural activities. This condition prompted the study of stakeholder’s perspective on the governance of Lake Victoria natural resources in Uganda. The purpose of the study was to analyse relevant stakeholders with a stake in wetland resource, their socio-economic characteristics, motives and perceptions on wetland degradation in the Lake Victoria Basin. We aimed at understanding how stakeholders influence decisions of managing wetlands in the Upper River Rwizi and Iguluibi micro catchments in light of the current farming systems and practices and their implications to the Lake Victoria Basin. A mixed method approach that includes both qualitative and quantitative surveying techniques was applied. We used a semi-structured questionnaire, focus group discussions, key informant interviews, ethnographic observations and secondary data. A stakeholder analysis framework was used to identify the relevant actors with a stake in wetland use and management. It further analyses their characteristics and perceptions of the problem of wetland degradation. Results reveal that around the 1950s, wetlands were intact ecosystems without any disturbances from human activities. Land use changes started around the 1990s when farmers started diversifying from subsistence-based economy to market-oriented. The interests, benefits and conflicts over use and management of wetland resources vary from one stakeholder group to another and their influence and power relations are quite distinct. These all combined with governance systems and perceptions influence the process of wetland degradation. the Upper River Rwizi and Iguluibi micro catchments in light of