Article

Vegetation health is a critical indicator of ecosystem resilience, agricultural productivity, and climate regulation, yet it is increasingly threatened by anthropogenic pressures and climatic variability. This study assessed the spatio-temporal dynamics of vegetation health in the Southern Guinea Savannah (SGS) agro-ecological zone of Taraba State, Nigeria, over 37 (1987–2024). Multi-temporal Landsat and Sentinel-2 imagery were processed to surface reflectance, cloud-masked, and analyzed using the Normalized Difference Vegetation Index (NDVI). Change detection and Mann–Kendall trend analyses were employed to quantify temporal trajectories, while Getis-Ord Gi* hotspot analysis identified degradation centers and conservation refugia. Results revealed a progressive decline in vegetation health, with dense forest cover (NDVI ≥0.61) contracting from 21.5% of the landscape in 1987 to isolated patches confined to the southeast by 2024. Degradation hotspots expanded eastward and consolidated into large contiguous zones in the northwest and central regions, while refugia fragmented into riparian corridors. The findings highlight severe erosion of ecosystem services, including biodiversity conservation, carbon sequestration, and watershed protection. Urgent interventions are required to safeguard remaining refugia and restore degraded landscapes in alignment with the Sustainable Development Goals and the Great Green Wall Initiative.