Spatio-temporal analysis of land use and land cover dynamics and the associated environmental implications in Hare river watershed, Ethiopia

摘要

Land use and land cover changes during 1967-2010 in Hare Watershed were analyzed using image analysis and GIS technologies and verified with the field situation. Five sets of satellite images (1976, 1985, 1995, 2003 and 2010) and aerial photograph of1967 were used as inputs to produce six GIS-based land cover maps of the area. The analysis revealed that land cover change and conversion has taken place during the last 43 years. Six land cover categories have been identified and they are Forests, Riverine vegetation, Farmland and Settlement, Bush and Shrubland, Woodland and Grazing lands. Farmlands and settlement has expanded dramatically at the expense of other land cover categories. The Farmland and settlement category existed to the extent of 5567.1 ha (23.8 %) of the watershed in 1967 but it expanded to 14808.2 ha (63.2 %) in 2010 gaining 9241.1 ha of land at the expense of other land cover categories. Forest cover was reduced by 78.7 percent; most of the destruction was a result of expansion ofagriculture. Other land cover categories were also lost to various levels during the entire study period: Woodland 61.4%, Riverine vegetation 55.2%, Bushes and Shrub lands 28.6% and Grazing land 14.9%. The present levels of these categories have been attributed to demographic pressures for land. The study suggests that proper land management and other policy issues are urgently required to reverse the situation for the sustainability of land resources.