摘要：Land use and land cover changes that occurred from 1957 to 1995 in the Dembecha area, Gojam, in the Northwestern highlands of Ethiopia, were monitored using a geographic information system (GIS) and a remote sensing approach with field verification. The study area covers 27,100 ha and is representative of Gojam, which is known for its cereal production and export of surplus to major cities of the country. However, given the age-old tradition of clearing increasingly steeper land for cultivation and the lack of appropriate land use policies, productivity is currently heavily threatened by soil degradation. The results show that the natural forest cover declined from 27% in 1957 to 2% in 1982 and 0.3% in 1995. The total natural forest cleared between 1957 and 1995 amounts to 7259 ha. This is 99% of the forest cover that existed in 1957. On the other hand, cultivated land increased from 39% in 1957 to 70% in 1982 and 77% in 1995. The greatest expansion occurred between 1957 and 1982 (about 78%) and slowed down between 1982 and 1995 (only 10%) because almost no land was left for further expansion. Throughout the period covered by the study, cultivation encroached upon the very last marginal areas and steep slopes with gradients >30%. Such a dramatic change in 4 decades and the increasing proportion of completely degraded lands, from virtually nil in 1957 to about 3% in 1995, clearly indicates the prevailing danger of land degradation in the area.
关键词：Land degradation; land use change; land cover change; remote sensing; GIS analysis; landscape analysis; Ethiopia
