Thermal stress reveals a genotype-specific tradeoff between growth and tissue loss in restored Acropora cervicornis

Coral restoration is gaining attention as a viable strategy to restore degraded reefs, with large-scale restoration efforts underway worldwide. However, our understanding of the drivers of restoration success lags behind restoration activities, generating significant knowledge gaps that may impede our ability to successfully restore coral reef communities. Here, we conducted a 21 mo field experiment to examine the influence of genotypic identity and diversity on coral growth, habitat production, and survivorship in restored corals. We used nursery-raised colonies of Acropora cervicornis, the predominant coral used for restoration in the Caribbean, to establish populations of either 1, 2, 4, or 6 distinct genotypes. Midway through our experiment, our study site experienced a 17 wk thermal stress event that allowed us to examine the influence of genotypic identity and diversity on the ability of restored corals to cope with thermal stress. After 21 mo we found no effect of genotypic diversity on restored corals, but that genotypes differed 3-fold in survivorship and 20 to 327% in habitat production. Initial growth rates showed a significant positive relationship with live tissue loss at the end of the experiment, suggesting a tradeoff between growth and the ability to recover from thermal stress. Our study suggests that genotypic identity is a critical factor to incorporate into coral restoration planning. Investigating the role of genotypic identity and diversity on the ability of restored corals to resist pervasive coral reef stressors, such as disease, predator outbreaks, and nutrient pollution, are critical steps in advancing coral restoration efforts.