Ecological Effects of Seaweed Restoration on Benthic Macrofauna in Marine Forest Development Areas Along the Eastern Coast of Korea

Although marine forest restoration projects have been widely implemented along the Korean coast, most evaluations have relied on simple structural indicators such as seaweed coverage or biomass, leaving functional responses of benthic macrofaunal communities largely unexplored. This study examined the effects of marine forest restoration on the functional structure of macrozoobenthic communities at development sites along Korea’s eastern coast in 2021 and 2024. Seaweed biomass increased significantly in 2024 compared to that in 2021, and this increase in seaweed biomass showed a clear positive correlation with increases in species number, density, and biomass of macrozoobenthos. Changes in feeding types of macrozoobenthic communities were remarkable, with grazer density increasing most sharply, followed by carnivores, omnivores, and suspension feeders. Red algal biomass was also positively correlated with suspension feeders and grazers, suggesting that seaweed mediated habitat and secondary food-web structures beyond providing simple food resources. These results indicate that seaweed habitat restoration plays an important role in recovering the functional diversity and feeding guild composition of macrozoobenthic communities and demonstrates the potential of using both species and functional diversity indicators to evaluate the effectiveness of marine forest restoration projects in Korea.