This study was conducted to investigate the impact of sand addition to an intertidal for the development of the Manila clam habitat on benthic community structure. For this, we focused on the spatio-temporal changes in the surface sediment condition and benthic community structure including Manila clam before and after the event. Study site was the lower part of Ojjeom tidal flat in Gonam-myeon, Taean-gun where sand added to on July 2010. We set three stations at each of sand adding area (experimental plot) and non sand-adding area (control plot) and did sampling works ten times from June 2010 to October 2011. Directly after the event, surface sediments changed to very coarse sand, but the state was not maintained over two months because of seasonal sedimentation and finally got back to the original grain sizes in eight months. The number of species and density were temporarily reduced right after the event and polychaetes such as Sternaspis scutata, Ampharete arctica were most negatively affected by the event. However, the number of species and density quickly recovered from the reduction in four to six weeks owing to the recolonization by the existing species and species in the vicinity of the plot. However, despite the recovery of ecological indies, species composition was continuously changed from one to another, thereby community structure stayed unstable condition, especially in some stations with finer sediment in their original condition. After sand addition, density of Manila clam was prominently increased at only one station with coarser sediment in its original condition.
