Geostatistical approach to assess mangrove spatial variability: a bi-decadal scenario over Raigarh coast of Maharashtra

Abstract

The present study aims at assessing the bi-decadal scenario related to the spatial variability of Mangroves over Raigarh district by adopting Geostatistical approach. Landsat TM/OLI data for the year 2000 and 2019 were employed for the study. Methodology adopted, involve computation and plotting of Semi-variogram (in ‘R’) with NDVI data, which was extracted for 28 homogeneous mangrove patches. These patches, based on similarity of Semi-variogram components, were further classified into clusters. Semi-variogram pattern for the year 2000 revealed a low range and high sill, indicating greater variation in the dataset that was correlated for a shorter distance. While in the year 2019, the Semi-variogram obtained for the same mangrove patches, exhibited high range and low sill. This clearly indicates a high spatial correlation associated with relatively low variation within the data. During the year 2019, some patches have shown evidences of exponential growth of mangroves that were represented by higher NDVI values, which were more similar, correlated and dependent. Overall rise in NDVI value indicates that the health status of mangroves has increased in 2019 along with natural expansion of mangrove colony. Over bi-decadal time span, mangrove ecology has also improved corresponding to higher NIR reflectance. The present research can be implemented to mangrove management and conservation purpose as this technique reveals the spatial dependency in the dataset.