Abstract

This study was conducted at Wallecha Watershed in the middle course of Bilate River Basin in Wolayitta Zone, Southern Ethiopia with the main objective of assessing the patterns of spatial and temporal dynamics of land use/land cover (LU/LC) and implications on sustainable land management (SLM). The study area was covered 10116.7ha, and had previously undergone substantial LU/LC changes. The changes in LU/LC which occurred between 1984 and 2010 were monitored in a context of geographical information system (GIS) and remote sensing (RS). The Lands at imageries of 1984, 2000 and 2010 were used to produce three land cover maps of the respective years using GIS and RS techniques with field verification. Changes in the density of vegetation cover and land degradation over time in the watershed were also estimated with the help of Normalized Difference Vegetation Index (NDVI). The general trend was observed as there is decrease in forest lands and shrubgrasslands at a rate of 34.27and 15.63ha per year respectively, and a decrease in degraded lands at a rate of 7.63 ha per year. A corresponding increase was observed in tree plantations and cultivated lands at a rate of 30.07 and 27.46 ha per year respectively. The decrease in forest lands and shrub-grasslands partly reflects the considerable degradation of natural vegetation in the watershed. Three state of vegetation disturbance levels viz. Highly, Moderately and Less stressed areas were identified and delineated using NDVI values which were measured through the analysis of the spectral reflectance of the red and the near infrared bands for the imageries. This finding has highlighted that the changes were not in favor of the natural ecosystem, rather triggered large scale clearing of forests and shrub-grasslands. Hence, greater emphasis must be given to wise use and SLM practices, regulated population growth and integrated environmental rehabilitation programs in the studied watershed.