How habitat setting influences restored oyster reef communities

Integrating how habitat heterogeneity influences food web dynamics is critical to enhance our understanding of community structure. This study quantified resident (invertebrates) and transient (juvenile and piscivorous fish) fauna within restored intertidal oyster reefs and analogous control sites without reef habitat in each of three habitats (on the edge of salt marsh away from seagrass, on mudflats isolated from vegetated structures, and in between seagrass and salt marsh habitat). Reefs enhanced the abundance of resident invertebrates (e.g., polychaetes, nemerteans, epibenthic anemones, bivalves, and resident decapods) that comprise > 90% of juvenile fish prey biomass. However, the increase in food availability due to reef presence did not affect abundance of juvenile fish in either of the vegetated habitats, suggesting that resources may not limit juvenile fish when restored in these habitats. Only mudflat reefs augmented juvenile fish abundances, most likely due to a combination of greater resource availability and relative isolation from functionally equivalent habitats. In addition, lower abundances of piscivorous fish in mudflat reefs relative to control areas likely contributed to this pattern. Thus, community structure and important ecosystem functions such as secondary production depend on the spatial configuration of surrounding habitats, in much the same way that species interactions can depend on their biotic and abiotic context.