Habitat Size and Location Drive Heterogeneity in Oyster Shell Colonization by Sessile Invertebrates

Oyster reefs form a critical, biogenic coastal habitat and host diverse assemblages of fish and invertebrates. Previous studies show that variation in the settlement and distribution of oyster reef inhabitants depends on factors such as flow and members of the benthic community. In other reef systems, such as coral reefs, the proximity of neighboring reefs also affects these patterns, yet this phenomenon is less explored in oyster systems. In this study, we tested the effects of habitat size and location on the colonization of sessile organisms living on restored oyster reef habitat. We placed cages filled with oyster shells of two sizes at two distances from the restored reef on the waterfront of St. Mary's College of Maryland. After 3 months, we collected the cages and identified and counted the individuals that colonized the shell. We found organisms responded differently to habitat size and location. For example, hooked mussel (Ischadium recurvum) abundance was primarily driven by proximity to the restored reef rather than the amount of available habitat. In contrast, Balanus spp. abundance was affected mainly by habitat size rather than location. Community composition depended only on habitat size. Therefore, habitat size and location can play an essential role in the community assembly of added oyster habitats through their taxon-specific effects.