Résumé
Coral reefs are sanctuaries for a large portion of our planet’s biodiversity, but their rapid decline begs critical questions about what exactly is being lost, what driving forces determine decline or resilience, and what implications for life on Earth. To help address these questions, this chapter synthesizes the state of knowledge on the diversity of coral reef life forms at different scales of biological and ecological organization, encompassing variability in genes, biomolecules, cells, organs, organisms, populations, communities, ecosystems, socio-ecosystems, and biogeoclimatic systems, with a particular focus on French tropical overseas. We discuss research pathways to address knowledge gaps in various scientific disciplines, covering genetics (genomics, transcriptomics, proteomics, metabolomics), morphology, ethology, bioacoustics, demography, functional ecology, macro-ecology, landscape ecology, human and social sciences, bioclimatology, and their cross-disciplinary interactions. Based on contributions from coral reef experts working in different coral reef regions around the world, our synthesis supports a better understanding of the various dimensions of coral reef biodiversity and proposes future research orientations for improving knowledge and conservation. Given the rapid disappearance of coral reefs and how much is still unknown, this chapter underscores the urgency of cross-scale biodiversity assessments for a systemic understanding of the distribution and dynamics of biodiversity.