Rethinking Artificial Reefs to Accelerate and Upscale Marine Biodiversity Recovery.

Artificial reefs (ARs), a form of anthropogenic intervention in marine habitats, have a long history of deployment and continue to proliferate worldwide. Based on a comprehensive literature review and meta-analysis, we show that (i) ARs have evolved from socioeconomic-oriented tools into often-used components of active marine restoration, yet this transition conflicts with the continued use of eco-unfriendly materials, hindering upscaling; (ii) ARs positively impact marine organisms at community, population, and individual levels, but their contributions to organismal fitness remain limited compared to natural reefs. To address these limitations, we advocate a paradigm shift toward "rewilding ARs"─temporary structures designed to create opportunities for natural reef formation, enhance habitat quality, and gradually degrade to minimize human impact. These features support the transition from active intervention to spontaneous recovery, promoting sustainable biodiversity recovery by improving organism fitness and facilitating upscaling. Integrating insights from ecologists, engineers, legal experts, environmental consultants, and NGOs, we introduce six guiding principles for "rewilding ARs" to ensure effective, durable, no-regret, scalable, permit-friendly, and outcome-optimized implementation. Lastly, we present pioneering examples of innovative ARs progressing toward these principles, serving as references for future endeavors.