The potential use of high-resolution Landsat satellite data for detecting land-cover change in the Greater Horn of Africa

To assess the potential of high-resolution satellite data for land-cover monitoring in the Greater Horn of Africa, we used a regular sampling grid of 170 sites (each measuring 20 km?×?20 km) located at the confluence of the latitudes and meridians across the study area. For each of these sites, Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) satellite data were acquired for the years 1990 and 2000. A dot grid visual interpretation was used to assess land-cover change between the two dates in each of the sites. With only two acquisition dates, we found that these data were insufficient for accurately determining land-cover change and degradation in arid areas where non-woody biomass dominates. We were nevertheless able to detect land-cover modifications in three areas: increases in agriculture on the coastal plain near Mogadishu, increases in agriculture at the western fringes of our study area where there is higher rainfall, and finally a reduction in woodlands and shrublands in areas close to refugee camps on the Somali–Kenya border.