Land use/ land cover dynamics and its impacts in nadda asendabo watershed, south western Ethiopia

Abstract

Understanding of the driving forces of land use/ land cover change is essential for effective sustainable land resource management. Change in LULC can also negatively affect the potential use of an area and may ultimately lead to land degradation. Hence, this study was conducted to investigate land use/ land cover dynamics, its drivers and impacts in Nada Asendabo watershed, south western Ethiopia. It covers an area of 8,012 ha. Information is extracted from three period land sat images (1973 MSS, 1986 TM and 2004 ETM+). The impacts of land use/ land cover were investigated through socioeconomic survey that involved household interview, key informants and FGD. Analysis of data was accomplished through integrated use of ERDAS imagine (version 9.2), Arc GIS (version 9.2) software and SPSS version 16.00 along with Microsoft office. Six land use/ land cover classes namely forest land, agricultural land, grass land, built-up area, reverine forest and bush land were selected for the study. Results from land use/ land cover change analysis showed an increase in agriculture land and built-up area from 19.16% and 1.46% in 1973 to 52.11% and 3.40% in 1986, 65.60% and 8.88% in 2004 respectively. The increase in agriculture land and built-up area was mainly at the expense of forest land, grass land, reverine forest and bush land. On the contrary, forest land, grass land, reverine forest and bush land decreased from 13.52%, 23.96%, 18.17% and 23.73% in 1973 to 5.28%, 20.54%, 6.30% and 12.37% in 1986, 4.75%, 8.5%, 4.36% and 7.91% in 2004 respectively. The result of socio-economic data analysis (the focus group participants and 96% of the sampled households) reported that agriculture, both crop and livestock productivity is declining. Clearance of vegetation has had an impact on the decline of agricultural productivity through soil fertility decline by the removal of vegetation cover and soil erosion. The removal of vegetation cover resulted in low availability of wood products, lack of livestock feed sources and reduced the overall income and income sources of farmers. Change in LULC negatively affect the potential use of an area and ultimately lead to soil and vegetation degradation and loss of productivity. Among many factors, the major production constraints was directly associated mainly with land use change. Among others, the major reasons for the decline in vegetation cover in the area include: expansion of cropland, harvesting of construction wood and firewood collection for domestic consumption. Increasing population is the major contributing factors. Hence, Studies of land use/ land cover dynamics can be used for land use planner, natural resource managers and policy makers to provide a management and decision process.