Assessment of restoration success in a transplanted seagrass bed based on isotopic niche metrics

Abstract

A major highlight of restoration efforts is to improve the ecological structure and function of the natural ecosystem in the restored habitat. Assessment of restoration success is a crucial component of an optimal ecological management strategy. In studies to determine the restoration success of a transplanted seagrass habitat by assessing trophic recovery, we examined carbon and nitrogen stable isotope ratios of organic matter sources and macrobenthic assemblages in a transplanted eelgrass Zostera marina bed. The eelgrass bed was restored about 2 years after transplantation in a southern coastal bay of Korea, and consequently, the food web structure in the bed was compared with that in a natural reference site. Our results revealed no significant differences in isotopic values of both macrobenthic consumers and their putative food sources between the transplanted and natural seagrass beds. These isotopic similarities in florae and faunae in the two beds suggest a uniformity in food web structure formed by the diversity and availability of resources, and thereby suggest similarities in the resource–consumer relationship. Isotopic niche indices and high dietary overlaps of feeding guilds in the transplanted and natural beds further suggest the transplanted habitat provides similar ecological functions and ecosystem services to its natural counterpart. Collectively, our results suggest the eelgrass transplantation led to successful restoration of a common seagrass bed, with recovery of the functional properties of the food web structure. Finally, our findings support the idea that stable isotope measures can provide a better understanding of the functioning of restored ecosystems, and improve post-transplantation monitoring efforts for the future planning and managing of successful habitat restoration.