Differences in resident prey survival on newly created shell and established natural intertidal oyster reefs

Abstract

Established natural oyster reefs historically provide a three-dimensionally complex habitat utilized by a variety of resident and transient species, but newly created reefs designed to counter the loss of natural reefs initially may lack similar complexity. The loosely stacked shells of newly created reefs little resemble the vertically interconnected live and dead shell matrix typical of older reefs. Reduced complexity on created reefs may alter predator–prey dynamics and negatively affect ecological functions typically associated with natural reefs. We examined select physical characteristics (e.g. shell morphology) and short-term survival of reef-resident prey to determine if differences exist between newly created (<1-year-old shell bags) and established natural intertidal reefs in South Carolina. Shell physical characteristics differed consistently between reefs, with greater numbers of smaller and lighter shells found on natural reefs. However, short-term survival of crabs (Panopeid sp.) and mussels (Geukensia demissa) generally was not dependent on reef type. The few instances of reef dependent prey survival were either inconsistent with expected results, assuming reduced complexity on created reefs, or not supported by effect size analyses. Evidence indicates that adding shell bags to create oyster reefs in intertidal environments almost immediately increases resident species survival similar to that on existing natural reefs and leads to the rapid return of a major ecosystem service associated with coastal oyster reefs.