Land Use/Cover Changes between 1966 and 1996 in Chirokella Micro-watershed, Southeastern Ethiopia

Abstract

Abstract:

Keywords: Land Cover; Dynamic; Expansion; Exposed Land; Reduction

Two periods of panchromatic aerial photographs taken in 1966 and 1996 were analyzed to determine spatial and temporal land cover changes occurring in Chirokella micro-watershed, Southeastern Ethiopia. Theresults of the analysis were digitized with Arc View GIS 3.3 software to produce land use/cover maps for 1966 and 1996. Five land use/cover categories, namely dense forest, moderately disturbed forest, bush, degraded and cultivated and settlement were identified. The result indicated an increase in an area of cultivated and settlement, bush and degraded and a decline in forest land cover categories over the 30 year period. The dense forest land cover decreased by over 80%, giving an average decreasing rate of 32 ha (-2.9%) per year. The moderately disturbed forest land was completely transformed to other land cover systems between 1966 and 1996. Cultivated and settlement land increased by 62.8%, giving an annual average expansion rate of 33.3 ha (+2.1%) over the analysis period. Bush and degraded land cover categories showed increasing patterns of 49.9% and 100%, respectively. Transformation of forest land cover to others could explain an increasing demand for more arable and settlement land and timber resources associated with a population increase and a decline in land productivity due to degradation. This expansion largely took place onto steeper and upper slope positions, which resulted in increasing the area prone to land degradation, and further implicates adapting of more forest to cultivated and settlement land use/cover categories. Thus, it seems that, in the micro-watershed land, cover changes resulted from combinations of physical (e.g. land degradation) and socioeconomic (e.g. demand for more land resources) factors.