This study assesses the risk of collapse of coral reef ecosystems in the Western Indian Ocean (WIO) using the IUCN Red List of Ecosystems (RLE) methodology. The assessment combined indicators of historical ecosystem extent change, ecosystem functioning (hard corals, algae, herbivores, piscivores), and projected sea temperature warming. The WIO coral reefs are found to be vulnerable to collapse at the regional level, with individual ecoregions ranging from critically endangered to vulnerable, primarily due to future warming and fishing pressure. The study emphasizes the need for ecosystem-based management and climate change mitigation and adaptation to prevent coral reef collapse. The methodology is replicable globally to support conservation and sustainability targets.

David Obura, Mishal Gudka, Melita Samoilys, Kennedy Osuka, James Mbugua, David A. Keith, Sean Porter, Ronan Roche, Ruben van Hooidonk, Said Ahamada, Armindo Araman, Juliet Karisa, John Komakoma, Mouchtadi Madi, Isabelle Ravinia, Haja Razafindrainibe, Saleh Yahya, Francisco Zivane