This study aimed to examine the population structure of Acropora tenuis and Acropora cytherea in the Chagos Archipelagos, by investigating intra-specific genetic variation of these two major reef building species. Chagos Archipelago have a unique combination of characteristics that results in negligible local stressors, making it an ideal base for studying the collapse and potential recovery of coral cover as a consequence of global climate change (GCC) induced stressors. The Archipelago has been recently impacted by mass bleaching events in two consecutive years (2015-2016) that lead to approximately 70% coral mortality across the Archipelago, 86% for the Acropora species.
This study demonstrates a lack of genetic structure in two Acropora species (with some degree of isolation for A. cytherea), suggesting a high degree of gene flow across the atolls in the Archipelago, as a result of good larvae dispersal. This indicates the potential for recovery in coral cover given time. However, increasingly frequent and severe thermal anomalies are predicted, as a consequence of accelerating GCC, potentially inhabiting recovery and leading to further coral loss. Further studies are needed to gain a proper understanding of the effect of a loss in genetic variability due to widespread coral mortality.
