Effects of dead oyster shells as a habitat for the benthic faunal community along rocky shore regions

Foundation species are crucial to understanding the mechanisms underlying faunal community structure. The present study aimed to clarify the habitat function of empty shells from dead oysters Saccostrea kegaki for the benthic faunal community of an intertidal rocky shore. We evaluated whether macroinvertebrates used the shells as a habitat. Results demonstrated that limpets (the dominant macroinvertebrates at the study site) did so more frequently than they inhabited live oysters, other sessile organisms, or rock surfaces. The dead oyster shells successfully functioned as a refuge from predation and as a nursery for limpets, because of their structural complexity (the presence of a depression on the inner side of the shell). Therefore, our study demonstrates the importance of dead S. kegaki, a shell-forming foundation species, and illustrates that the structural complexity of such species might result in habitat functions upon their death.