Artificial structures can facilitate rapid coral recovery under climate change

Rising seawater temperatures from climate change have caused coral bleaching, risking coral extinction by century's end. To save corals, reef restoration must occur alongside other climate-change mitigation. Here we show the effectiveness of habitat creation on artificial structures for rapid coral restoration in response to climate change. We use 29 years of field observations for coral distributions on breakwaters and surrounding reefs (around 33,000 measurements in total). Following bleaching in 1998, breakwaters had higher coral cover (mainly Acropora spp.) than did surrounding natural reefs. Coral recovery times on breakwaters matched the frequency of recent bleaching events (~ every 6 years) and were accelerated by surface processing of the artificial structures with grooves. Corals on breakwaters were more abundant in shallow waters, under high light, and on moderately sloped substrate. Coral abundance on breakwaters was increased by incorporating shallow areas and surface texture. Our results suggest that habitat creation on artificial structures can increase coral community resilience against climate change by increasing coral recovery potential.