A comprehensive geospatial assessment of seagrass distribution in India

Abstract The study deals with the first comprehensive spatial distribution and area estimate of seagrasspatches of India with a standardized methodology. Seagrasspatches are mainly located in Palk Bay – Gulf of Mannar ( TamilNadu), Gulf of Kachchh (Gujarat), Chilika Lake (Odisha) and Islands of Andaman & Nicobar and Lakshadweep. Medium resolution satellite images of Landsat 8 OLI were subjected to radiometric, atmospheric and water column correction prior to digital classification and contextual editing. Total estimated seagrassarea amounts to 516.59 km 2 of which Palk Bay and Gulf of Mannar of TamilNadu together contribute to 398.81 km 2 . Overall classification accuracy for the six sites studied, ranged between 64% ( LakshadweepIslands) and 83.5% (Palk Bay). This suggests that for surveillance studies of homogeneous seagrassmeadows with low interspersion of other benthic units such as corals, seaweeds etc., digital mappingusing medium resolution data sets with mandatory attenuation correction procedures is suitable. The results of this study and the related area statistics were accepted as a baseline at national level for the delineation of Ecologically Sensitive Areas (ESA) and in the formulation of its conservation strategies. For a cursoryappraisal of the status of major seagrassregions, a matrix representationof its locational occurrence and habitat characteristics is provided.