Beyond Restoration: Floating Reefs as Self-Sustaining Biodiversity Hubs

Coral reef degradation has accelerated the development of active restoration approaches, including the use of mid-water coral nurseries (Floating Reef Devices; FRDs) designed to enhance coral growth and survival. Although primarily used for coral propagation, the broader ecological roles of FRDs remain poorly understood. We assess the biodiversity and ecological structure of a long-term FRD deployed in the Gulf of Eilat over two decades as an active coral nursery. We surveyed naturally recruited sessile organisms and associated fish communities, quantifying taxonomic breadth and distinctness (Δ+), functional diversity, and trophic structure. The FRD supported a diverse community spanning eight phyla and 128 genera, with high taxonomic distinctness and wide functional trait representation across multiple trophic levels. Despite lower genus richness compared to natural habitats, coral and fish assemblages exhibited taxonomic and functional patterns that fell within the range observed for the adjacent natural reef. Functional analyses showed that the FRD’s coral assemblage occupied nearly the full regional trait space, while fish biomass was dominated by planktivores and secondary consumers, indicating a differently structured trophic organization. These findings demonstrate that long-term floating nursery systems can develop into structurally complex, multi-trophic communities, providing ecological and conservation values and ecosystem services beyond their original restoration role. These findings provide an ecological foundation for future studies of floating restoration systems and their associated ecological roles, while also informing their design, implementation, and evaluation as practical tools for enhancing ecosystem recovery and associated ecological functions.