Monitoring basin-scale land cover changes in Kagera Basin of Lake Victoria using: Ancillary data and remote sensing
International Journal of Applied Earth Observation and Geoinformation
Faculty for Geo-Information Science and Earth Observation, Twente University, P.O Box 217, 7500 AE Enschede, Netherlands; Department of Agricultural Production, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda; Soils and Soil Research Programme, National Agriculture Research Laboratories (NARL) Kawanda (Uganda), P.O. Box 7065, Kampala, Uganda
The Kagera Basin is a high value ecosystem in the Lake Victoria watershed because of the hydrological and food services it provides. The basin has faced large scale human induced land use and land cover changes (LUCC), but quantitative data is to date lacking. A combination of ancillary data and satellite imagery were interpreted to construct LUCC dynamics for the last century. This study is an initial step towards assessing the impact of LUCC on sustainable agriculture and water quality in the watershed. The results show that large trends of LUCC have rapidly occurred over the last 100 years. The most dominant LUCC processes were gains in farmland areas (not detectable in 1901 to 60% in 2010) and a net reduction in dense forest (7% to 2.6%), woodlands (51% to 6.9%) and savannas (35% to 19.6%) between 1901 and 2010. Forest degradation rapidly occurred during 1974 and 1995 but the forest re-grew between 1995 and 2010 due to forest conservation efforts. Afforestation efforts have resulted in plantation forest increases between 1995 and 2010. The rates of LUCC observed are higher than those reported in Sub Saharan Africa (SSA) and other parts of the world. This is one of the few studies in SSA at a basin scale that combines multisource spatio-temporal data on land cover to enable long-term quantification of land cover changes. In the discussion we address future research needs for the area based on the results of this study. These research needs include quantifying the impacts of land cover change on nutrient and sediment dynamics, soil organic carbon stocks, and changes in biodiversity. © 2012 Elsevier B.V.
afforestation; alternative agriculture; anthropogenic effect; biodiversity; data interpretation; ecosystem modeling; future prospect; land cover; land use change; monitoring system; nutrient dynamics; quantitative analysis; remote sensing; research work; satellite imagery; sedimentation rate; soil organic matter; trend analysis; vegetation dynamics; water quality; East African Lakes; Kagera River; Lake Victoria; Sub-Saharan Africa