Assessment of the coral habitability status of marine ecosystems along the eastern coast of the Andaman Islands, India

Abstract

The Andaman Islands, hosting one of the most enriched marine ecosystems globally, have faced significant ecological threats due to various physico-climatic changes over recent decades, adversely impacting approximately 25 mangrove species and 135 coral species. To evaluate these impacts systematically on regional marine ecology, this study develops and applies a coral habitat quality index (CHI) along the eastern Andaman coast using an integrated approach combining key physico-climatic indicators, participatory coastal community appraisals, and geospatial analysis. A total of 187 georeferenced sampling points within a 5 km offshore buffer were analysed for the years 2008, 2013, and 2018. The Analytic Hierarchy Process (AHP) was employed to prioritise factors influencing coral habitat conditions, with stakeholder-based pairwise comparisons from four distinct coastal community groups forming the basis for CHI computation. Results reveal that the southern zone of the eastern coast has progressively developed into a relatively healthier marine habitat than its northern and central counterparts, with CHI values averaging 1.24 (2013–2018), compared to 1.01 and 1.08, respectively. Notably, offshore zones south of Rangat exhibit the most ecologically resilient characteristics, evidenced by a consistent rise in CHI scores across the study period. The methodological framework presented here enables replication across comparable island and coastal ecosystems, offering a scalable decision-support tool for marine conservation planning, impact monitoring, and adaptive coastal resource governance. Overall, this study advances technical insight into spatio-temporal coral habitat dynamics while supporting evidence-based policy and sustainable marine ecosystem management strategies.