Seascape genomics as a new tool to empower coral reef conservation strategies: an example on north‐western Pacific Acropora digitifera

International audienceCoral reefs are suffering a major decline due to the environmental constraints imposedby climate change. Over the last 20 years, three major coral bleaching eventsoccurred in concomitance with anomalous heatwaves, provoking a severe loss of coralcover worldwide. The conservation strategies for preserving reefs, as they are implementednow, cannot cope with global climatic shifts. Consequently, researchersare advocating for preservation networks to be set-up to reinforce coral adaptive potential.However, the main obstacle to this implementation is that studies on coraladaption are usually hard to generalize at the scale of a reef system. Here, we studythe relationships between genotype frequencies and environmental characteristics ofthe sea (seascape genomics), in combination with connectivity analysis, to investigatethe adaptive potential of a flagship coral species of the Ryukyu Archipelago (Japan).By associating genotype frequencies with descriptors of historical environmental conditions,we discovered six genomic regions hosting polymorphisms that might promoteresistance against heat stress. Remarkably, annotations of genes in these regionswere consistent with molecular roles associated with heat responses. Furthermore,we combined information on genetic and spatial distances between reefs to predictconnectivity at a regional scale. The combination of these results portrayed the adaptivepotential of this population: we were able to identify reefs carrying potential heatstress adapted genotypes and to understand how they disperse to neighbouring reefs.This information was summarized by objective, quantifiable and mappable indices coveringthe whole region, which can be extremely useful for future prioritization of reefsin conservation planning. This framework is transferable to any coral species on anyreef system and therefore represents a valuable tool for empowering preservation effortsdedicated to the protection of coral reefs in warming oceans