Decadal Intensity Analysis and Landscape Fragmentation of Land Use land Cover Change in the Owesse River Basin, Southwest Nigeria

Land use and land cover (LULC) change and landscape fragmentation pose significant threats to ecosystem sustainability in tropical river basins, particularly in rapidly developing regions of sub-Saharan Africa. This study assessed the spatio-temporal dynamics, intensity, and fragmentation of LULC change in the Owesse River Basin, Southwest Nigeria, over a 30-year period (1994–2024). Multi-temporal Landsat imagery (TM, ETM+, and OLI-TIRS) was classified into five LULC categories using supervised maximum likelihood classification, with overall accuracies exceeding 85%. Post-classification change detection was integrated with Intensity Analysis to evaluate interval-, category-, and transition-level changes, while landscape fragmentation was quantified using Morphological Spatial Pattern Analysis (MSPA) and FRAGSTATS metrics. Results revealed significant transformations across all land-cover classes. Forest cover declined markedly, while light vegetation (agriculture) and built-up areas expanded substantially, indicating increasing anthropogenic pressure. Barren land exhibited fluctuating trends associated with land degradation and recovery, whereas water bodies showed slight increases over time. Interval-level analysis identified 2004–2014 as the most active period of change. Category-level results showed forest as a dominant losing class, while light vegetation and built-up areas were active gaining classes. Transition-level analysis revealed systematic conversions primarily from forest to agricultural land and built-up areas, alongside secondary transitions involving other land-cover types. Fragmentation analysis indicated increasing landscape heterogeneity, characterized by reductions in core areas and increases in edge and isolated patches, reflecting declining connectivity. Overall, the findings highlight a transition from natural to human-dominated landscapes driven by agricultural expansion and urbanization. The study demonstrates the value of integrating intensity analysis with landscape ecological metrics and provides critical insights for sustainable land-use planning and ecosystem conservation in tropical river basins.