A major goal of coral restoration is to revive populations of stony corals that provide structure and habitat for the rest of the coral reef community, including soft corals, urchins, lobsters and fish. However, as restoration efforts expand around the globe, it is becoming increasingly clear it is not enough just to outplant corals. Healthy coral reefs are diverse communities with many intricate relationships between species that live on and around them.
…Fish also help corals grow by excreting nitrogen, an important nutrient for the symbiotic algae that live inside corals. This allows the algae to give more energy back to corals and make them grow faster. Planting coral at restoration sites in dense aggregations may help attract more fishes, which will fertilize the corals, help them grow and attract more fish.
However, planting corals too densely can hasten disease transmission and competition between them – factors that can drastically impede the success of restoration. Finding the sweet spot, where corals are grouped densely enough to promote growth and attract fish but not so densely that they spread diseases and complete with each other, should be incorporated into restoration design.
…There are many more processes that restoration practitioners can harness to help facilitate repopulating reefs with corals. The future of coral restoration lies in combining experience in growing corals for transplantation with accumulated ecological knowledge about how reefs function. Until now, those two camps generally have operated in separate spaces. With corals in crisis worldwide, it is time to bring them together.