Mapping of landscape structure and forest cover change detection in the mountain chains around Addis Ababa: The case of Wechecha Mountain, Ethiopia

Abstract

Addis Ababa, the capital city of Ethiopia is, a tropical city, found on a high elevation between 2000 m and 3000 m above sea level. The city is bordered by high rise mountains, Entoto Mountain in the North, Wechecha Mountain in the West, Furi Mountain in the South and Yerer Mountain in the East which have a crucial influence on determining the climate of the city. This study, therefore, focuses on landscape structure and forest cover change on Mount Wechecha, which has a great contribution in the regulation of modifying micro climate of the city and the environ, not only due to its elevation but also due to its dense forest cover. Monitoring land cover changes in a mountain ecosystem help to understand and pinpoint the strategy to be followed for the conservation of ecosystems found on the neighbouring mountains, which also have a great influence on regulating the climate of the city. The study uses five Landsat satellite images to derive land cover of Mount Wechecha from 1973 to 2013. Landscape structures and matrixes have been analyzed and mapped based on the patch-corridor-matrix ecological model. The results have shown that the patch analyst result is proportional to the land cover classes derived from the satellite image. The landscape structure indices of the number of patches are decreasing in all years, except for water and settlement. The forest patches are dissolved into agricultural lands. The mean core area of the forest that increases indicates that the forest coverage is limited to certain places. The Mean Core Area of agricultural land decreased in the last decade due to the agricultural land being interrupted by other economic activities, which leads to landscape modifications. Shannon's evenness and diversity index was zero. The overall result indicates that the forest, which play a great role in climate regulation and open land coverages are decreasing at a faster rate (30% and 24.5% in 1973–14% and 2.4%. in 2013 respectively), while settlement is highly increasing (from 1.3% to 26.25% same period). Hence, the priority has to be given to protecting forest loss of Mount Wechecha and other forests on the neighbouring mountains surrounding Addis Ababa in order to have favorable climate conditions in the city. Such type of studies on mountain chains are very vital in considering appropriate environmental planning mechanisms and to formulate policies at the landscape level.