Studying the genomics of natural and restored populations of Acropora palmata is crucial for understanding their genetic diversity and the impact of conservation efforts

Abstract

Coral reef ecosystems in the Caribbean are on the brink of ecological collapse, largely due to the significant decline in once-abundant populations of Acropora species. For this reason, Acropora palmata is now classified as critically endangered by the IUCN. In response, restoration programs are in place, but assessment of the genomic diversity of colonies used for restoration has lagged. We studied the genome-wide variation of A. palmata using a low-coverage whole genome approach in Quintana Roo, Mexico. We collected over a hundred colonies across reefs spanning over 150 km, including one reef under active restoration efforts. Our analysis based on thousands of genome-wide markers, revealed high levels of genomic diversity with low levels of clonality. Remarkably, the reef under restoration showed genetic diversity comparable to the natural populations, while just one reef presented decreased genetic variability. Our results indicate gene flow among populations with subtle patterns of genetic differentiation, suggesting limiting geographic isolation. We demonstrate that coral restoration from naturally occurring fragments and sexual recruits encompasses sufficient genetic variation on par with that of natural populations. Therefore, we ascertain that current restoration efforts in Quintana Roo include enough genetic diversity to maintain nurseries and provide a viable long-term approach to restoring natural populations of decimated Acroporids in Mesoamerican reefs.