Integrated Remote Sensing Approach to Desertification Monitoring in the Crop-Rangeland of Yobe State, Nigeria

Abstract

One of the most important recent issues facing Yobe State, North Eastern Nigeria, as well as Sub-Saharan Africa, is the threat of continued land degradation and desertification as a result of climatic factors and human activities. Remote sensing and satellites imageries with temporal and synoptic view, play a major role in developing a global and local operational capability for monitoring land degradation and desertification in dry lands, as well as in Yobe State.The process of desertification in Yobe State, especially in Yusufari, Nguru, Karasuwa, and Bade areas, has increased rapidly, and much effort has been devoted to define and study its causes and impacts. This study depicts the monitoring capability afforded by remote sensing to analyze and map the desertification processes in Yobe State by using supervised classification by maximum likelihood technique. Three cloud-free Landsat; Multispectral Scanner (MSS) sensor on board the Landsat-2, Thematic Mapper(TM)sensor on board the Landsat-5 satellite and Enhanced Thematic Mapper (ETM +) scenes covering the study area were selected for analysis. Imageries were acquired in January (the dry and rainy season in the study area) in years 1973, 1986, and 2006, respectively. Application of multi-temporal remote sensing data on this study demonstrated that it is possible to detect and map desertification processes in the study area, as well as in arid and semi-arid lands. The results emphasized the phenomena of sand encroachment from the northern part (Yusufari) to the southern part (Bade), following the wind direction. The increasing wind speed during the dry season is mainly attributed to the increase of sand encroachment in the study area. The study comes out with some valuable recommendations and comments, which could contribute positively in reducing sand encroachments, as well as land degradation and desertification processes in Yobe State.