ASSESSMENT OF DESERTIFICATION DYNAMICS USING NDVI TIME SERIES IN MARGINAL LAND AREAS OF JIGAWA STATE

Abstract

This study examines the spatiotemporal trends in desertification in marginal land areas of Jigawa State, Nigeria, utilizing Normalized Difference Vegetation Index (NDVI) time-series analysis from 2015 to 2024. Landsat 8 satellite imagery was applied to derive NDVI values for both dry (February) and wet (June) seasons, and vegetation cover was classified into four categories: Very Low, Low, Moderate, and High. The Mann-Kendall test and Sen’s Slope Estimator were used to assess the statistical significance and magnitude of NDVI trends over the study period. Findings reveal a sharp decline in the area covered by Low NDVI values during the dry season, with a 63% reduction between 2015 and 2024, indicating progressive vegetation degradation in arid months. Conversely, Moderate and High NDVI classes exhibited consistent increases in both February and June data, suggesting improved vegetation conditions and partial recovery in previously degraded zones. The results reflect an overall positive trend in vegetation health, particularly during the wet season. This study demonstrates the effectiveness of NDVI time-series analysis for monitoring land degradation and guiding sustainable land management practices. It stresses the need for the sustained use of remote sensing techniques in environmental assessment and policy planning to combat desertification in semi-arid regions.