Chapter 9: Modelling and Monitoring of Mangrove Vegetation Health Risks and Stress using LANDSAT Satellite Data

Climate change increasingly affects mangrove vegetation, impacting their physiological traits and indicating health risks and stress. This study assesses climate-related stress in the Indian Sundarbans using Landsat imagery, Climatic Research Unit (CRU) climate data, and a 2022 survey of 300 locals on climate perceptions. Various vegetation indices (VIs) were applied to evaluate greenness and canopy water content, which helps to mangrove health monitoring and informs policymakers. Furthermore, the Mann–Kendall (MK) test and Garrett ranking were used to assess the changing trend of climatic parameters and related perceptions, respectively. Additionally, ordinary least squares (OLS) and Pearson correlation analyses were conducted to investigate the spatio-temporal fluctuations in vegetation and their associations with climate variables. The results of the MK test indicate that there was no statistically significant trend (H₀ > H_a). Additionally, the Garrett analysis confirmed that the perception of climatic variability (73.57), climate disasters (64.90), and diseases (51.06) were the most influential factors that contribute to the risk and stress on mangrove health in the study region. Subsequent analysis of VIs revealed adverse impacts of climate change on mangroves. Variability in spectral indices values of greenness (Ratio Vegetation Index (RVI) = −0.30, Normalised Difference Vegetation Index (NDVI) = −0.07, Atmospherically Resistant Vegetation Index (ARVI) = −0.29, Enhanced Vegetation Index (EVI) = 0.03), canopy water (Normalised Difference Water Index (NDWI) = 0.02, Modified Normalised Difference Water Index (MNDWI) = 0.008, Moisture Stress Index (MSI) = −0.01, Normalised Difference Infrared Index (NDII) = −0.01) models reflect deteriorating health conditions and increased stress levels within the ecosystem. The present study helps to understand the relationship between climatic variables and VIs and supports decision-makers on the significance of continuous monitoring and the potential for sustainability in mangrove ecosystems.