Mapping Land Degradation in the Sahel Zone of Yobe State Using Remote Sensing

Land degradation in the Sahel region of North East Nigeria threatens food security and pastoral livelihoods. This study maps land degradation in Yobe State using Landsat 8 and Sentinel-2 imagery acquired between 2019 and 2023. The study employs a combination of spectral indices including the Normalised Difference Vegetation Index, the Bare Soil Index, and the Salinity Index to characterise degradation types including wind erosion, salinisation, and vegetation stripping. Principal component analysis is applied to reduce data dimensionality and enhance feature separability in the classification process. Results reveal that approximately 37 percent of the state's land surface exhibits moderate to severe degradation, concentrated in the northern local government areas of Yunusari, Nguru, and Bade. The spatial pattern correlates strongly with low annual rainfall, soil texture, and high livestock density derived from secondary datasets. The study documents recent rehabilitation efforts under the Great Green Wall initiative and evaluates their spatial extent using post-intervention imagery. Findings support the Yobe State Agricultural and Rural Development Authority in targeting land restoration interventions in the most degraded zones. Keywords: land degradation, Sahel, Yobe State, vegetation index, desertification mapping