Abstract
Mangrove habitats in Myanmar’s Irrawaddy Delta are increasingly exposed to climatic variability and intensifying land-use pressure, yet long-term vegetation greenness dynamics at the delta scale remain insufficiently characterized. In this study, we have integrated Moderate Resolution Imaging Spectroradiometer–derived Normalized Difference Vegetation Index (NDVI) with Land-Use and Land-Cover (LULC) datasets to quantify three decades (1994–2024) of vegetation change and its environmental drivers. LULC maps were generated using a Random Forest classifier (overall accuracy: 88%, Cohen’s κ = 0.85), and class-specific areas were reported with uncertainty using per-class User’s Accuracy. Mangrove extent declined from 1,927.31 ± 580.24 km² in 1994 to 1,134.84 ± 341.65 km² in 2024, equivalent to a net loss of 792.47 ± 673.20 km² (95% confidence interval). Greenness dynamics were evaluated using pixel-wise linear trends, lagged correlations, and multiple regression with multicollinearity diagnostics. Nonlinear response thresholds identified using generalized additive models showed marked reductions in peak greenness under prolonged dry-season duration (> 4 months with < 50 mm rainfall) and extended heat exposure (> 30 °C for > 70 days). Spatial stratification by elevation and landscape fragmentation revealed stronger precipitation–NDVI relationships in relatively intact mangrove stands and weakened correlations in converted or degraded landscapes. Overall, the study shows that long term land use conversion and emerging climate related stress are jointly weakening mangrove resilience, while offering transferable methods and decision ready baselines that support global coastal restoration, climate risk reduction, and sustainable land use planning.
