Land-use Changes in the Ethiopian Highlands: Use of GIS in Resource Management Research

Unmitigated deforestation and land degradation under increasing demographic pressure make the East African highlands (1500 m above sea level) one of the most fragile ecosystems in the world. About 80% of Ethiopia's population of 57 million live in the highlands and the population will rise to 177 million by the year 2030. The reversal of damaged lands needs solutions to combine land uses that increase pro-ductivity, ensure diversity of commodities and conservation of natural resources. Questions must be addressed such as: What contributes to the cur-rent land use systems? How widespread are the prob-lems and what problems limit production most? Where and how can produc-tivity improvements be made? What should be the strategies to achieve them?

To identify constraints and development opportunities, and integrate compatible land-use systems for productivity improvement and resource management, ILRI collaborated with the Ethiopian Institute of Agricultural Research (IAR) and ICRISAT and identified a 343 ha watershed near Ginchi, 80 km west of Addis Ababa of which 60% are Vertisols. From panchromatic aerial photo-graphs for years 1957, 1971 and 1980 and 1994, land-use changes were assessed assuming 1957 as the base year and using the conventional planimetric technique and ground-truthing. Retrospective ground-truthing was aided by the aerial photo-graphs taken during the same period each year, and informal discussions with elders in the area to interpret land-cover features. For delineation of gully and drainage lines, a mirror stereoscope was used, and each tracing then registe-red on a real coordinate using a reference topographic map at a 1:2000 scale digitised with ARC/INFO. From the contours, the digital elevation model of watershed was derived at 1 meter grid resolution and the altitude slope and aspect digi-tal maps were produced with the help of IDRISI. Land-use, drainage line and gully maps were also digitised using ARC/INFO. Maps of land-use and land degradation trends. Crop land Grass land Bush land Riverain Trees

Ginchi Watershed: Land-use change, left 1957, right 1994

Contact: Mohamed A. Mohamed-Saleem, International Livestock Research Institute (ILRI) PO Box 5689, Addis Ababa, Ethiopia Phone: +251 1 61 3215 Fax: +251 1 611892 E-mail: m.saleem@cgnet.com | http://www.cgiar.org/ilri