Multi-temporal Analysis of Vegetation Dynamics Over Three Decades for Sustainable Management of Woody Vegetation: The Case of Abaya-Gelana Area, Borena Zone, Southern Ethiopia

Abstract

Up-to-date and reliable land use/land cover (LULC) information forms an essential component of local and regional planning. So, the aim of the present study is to analyze and quantitatively evaluate LULC changes in Abaya-Gelana area between 1986 and 2015 using remotely sensed data and techniques. To realize the aforementioned objective, cloud free orthorectified multispectral land sat 5 thematic mapper (TM) acquired in 1986 and land sat 8 operational land imager (OLI) acquired in 2015 were used for LULC change detection. In addition to the land sat images, collateral information was obtained from topographic maps, field data, and Google earth images. After digital image processing and visual interpretation of the land sat images, supervised classification with maximum likelihood algorithm was applied and LULC maps for 1986 and 2015 were produced. Finally, post-classification comparison was made to analyze LULC changes over the past three decades. The results of the change detection analysis show that there is obvious deforestation problem in the study area which is manifested by the reduction of bushland by 46.89% and an increase in bareland by 253.34% within 29 years. Besides, a reduction in grass land, a remarkable increase in cultivated land, urban expansion, an increase in water surface are among the major LULC changes over the past three decades.