Lessons learned from using large oyster reef restorations to facilitate seagrass restoration

Seagrass meadows provide critical habitat for ecologically and economically important species, yet have suffered extensive losses globally and can be extremely costly to restore. Oysters and seagrass are known to co‐occur and often have a facilitative relationship, suggesting the potential for oyster reef restorations to support seagrass recovery. This study assessed the possibility of one restoration bolstering another by investigating if large subtidal boulder reefs constructed to recover oyster habitat could also facilitate nearby seagrass recovery. To test the hypothesis that oyster reef construction enhances seagrass recruitment, seagrass restoration bags—based on a method proven successful in the region—were placed at sites close to and far from the newly built reefs. Survival and recruitment rates were recorded over two annual recruitment periods. Contrary to the hypothesis, boulder reefs reduced the survival of seedlings for one species of seagrass and had no significant influence on the recruitment of a second species. Despite the small‐scale and short‐term nature of this experiment, these boulder reefs represent large‐scale and long‐term experiments that will be necessary to monitor over decadal scales to develop a more effective understanding of the realized impact of the reef restorations on nearby seagrass habitat.