Dense clusters improve efficiency and foster colony development in restored Acropora cervicornis

A primary objective of coral restoration is to foster the development of large, sexually reproductive colonies to reseed degraded reefs. Practitioners of Acropora cervicornis restoration favor outplanting large individuals spaced more than 50 cm apart; however, this contrasts with this species' tendency to form high-density thickets with multiple colonies and genotypes in close proximity. Furthermore, large outplants are difficult to grow and transport, limiting scalability. We outplanted dense clusters containing multiple small, monoclonal fragments spaced 1-2 cm apart and compared their performance with that of large fragments of the same genotype planted individually. We further investigated the effect of clonal diversity by combining multiple genotypes within clusters. Dense clusters had equivalent growth and higher survivorship than large individuals and were not hindered by genotypic diversity. Our findings support outplanting dense, polyclonal clusters as a method to cultivate large, resilient A. cervicornis colonies.

Automated summary

A primary objective of coral restoration is to develop large, sexually reproductive colonies for reseeding degraded reefs. However, Acropora cervicornis restoration usually involves outplanting large individuals spaced apart, which contrasts with the species' tendency to form dense thickets with multiple colonies and genotypes nearby. This study found that outplanting dense clusters of small, monoclonal fragments spaced closely together had equivalent growth and higher survivorship compared to large individuals, regardless of genotypic diversity. These findings support the use of dense, polyclonal clusters for cultivating large, resilient A. cervicornis colonies.