Long-term effect of coral transplantation: Restoration goals and the choice of species

The transplantation is an important method for the restoration of degraded ecosystem. However, it is unclear how the choice of species and transplantation mode affects the community dynamics during recovery from a disaster, particularly for long-lived organisms such as corals. To address this issue, we study a population dynamic model of multiple species in multiple habitats connected by larval dispersal. We first consider two species showing the trade-off relationship between growth rate and mortality and examine three restoration goals to evaluate the effectiveness of transplantation: total coverage; species diversity spatial heterogeneity of species composition. To promote the rapid development of total coverage, the transplantation of fast-growing species should be adopted. To maintain a high level of regional species diversity, the transplantation of slow-growing species or short-dispersal species is effective. Next, we suppose four genera of corals - Acropora, Pocillopora, Porites, and Favites - as an example of coral community in Okinawa where Pocillopora is facing to local extinction. In addition to three indexes recovery of locally endangered species is evaluated as a restoration goal. Results show that to promote the recovery of Pocillopora, the transplantation of the same species is clearly the most effective choice. In contrast, the transplantations of Acropora and Porites led to undesirable results. In summary, these results indicate that both the restoration goal and the transplanted species must be carefully selected before conducting transplantation operations.