Survival and growth of “branches of opportunity” from ten coral species outplanted on framed reef modules

Abstract

To reveal local coral species aptness for reef restoration, 30 “framed reef modules” (FRMs) were deployed in a degraded coral reef area at the northern part of Wuzhizhou Island, Hainan Island, South China Sea. Fragments of opportunity from 10 coral species (8 branching, 1 foliose, 1 encrusting) were collected and outplanted on the FRMs. Measurements of growth rates, survival, and physiological indexes were then taken at 30, 120, 210 and 360 days after transplantation. The results showed that Acropora microphthalma, Acropora austera, Hydnophora rigida and Montipora foliosa showed fast growth rates (>2.87 cm²·month⁻¹) and high one-year survival rates (>80 %). Acropora hyacinthus and Montipora digitata, while exhibiting faster growth rates (4.95 ± 0.31 and 4.85 ± 0.41 cm²·month⁻¹, respectively), revealed lower one-year survival rates (ca. 50 %). Psammocora contigua and Porites cylindrica showed lower growth rates (1.50 ± 0.14 and 1.96 ± 0.19 cm²·month⁻¹, respectively), yet presented 100 % survival rates. Pocillopora damicornis and Echinopora gemmacea exhibited the lowest growth rates (1.01 ± 0.14 and 1.73 ± 0.21 cm²·month⁻¹, respectively) and 86.2 % and 93.1 % survivals. There are differences in growth and survival among different types of corals, which are closely related to their physiological characteristics. The biomasses of P. contigua, P. cylindrica, and M. foliosa were the highest, >10 mg·cm⁻², while for the remaining 7 species values were > 8 mg·cm⁻². The highest photosynthesis rates were recorded in P. contigua, P. cylindrica, A. austera, and M. digitata, while the lowest were in P. damicornis and H. rigida. These results demonstrate significant interspecific differences in survival and growth patterns, highlighting the importance of species-specific restoration strategies. The present transplantation method supports restoration approaches that combine different coral species in a single transplantation action.