Analysis of Desertification Indicators in the Sahel Fringe of Yobe State, North East Nigeria

Desertification and land degradation in Nigeria's North East geopolitical zone continue to threaten agricultural livelihoods, pastoralist systems, and environmental stability across the Sahel fringe. This study analyses key desertification indicators in three local government areas of Yobe State, namely Bursari, Yunusari, and Karasuwa, using multi-source geospatial data and field observation. Indicators examined include vegetation density changes measured through the Normalised Difference Vegetation Index (NDVI), sand dune encroachment rates, topsoil loss, and wind erosion scars identified through time-series Landsat imagery spanning 2015 to 2024. Meteorological data from the Nigeria Meteorological Agency and soil sample analyses from twelve sampling stations were integrated into the assessment framework. The study records a statistically significant decline in mean NDVI values across all three local government areas over the study period, with the most pronounced vegetation loss observed during prolonged dry season months from December to March. Sand dune movement was quantified at an average rate of 4.8 metres per year, threatening existing farmland in Yunusari. Farmer household interviews conducted in 45 communities reveal heavy dependence on groundwater and millet cultivation, both of which are increasingly precarious under advancing desertification. The study recommends accelerated implementation of the Great Green Wall Initiative in Yobe State, integration of drought-resistant crop varieties, and community-based land rehabilitation programmes. Keywords: desertification, NDVI, sand dune, Yobe State, North East Nigeria.