Comparisons of macrofaunal assemblages on restored and non-restored oyster reefs in mesohaline regions of Chesapeake Bay in Maryland

Abstract

Maryland's recently created oyster restored reefs provide us with a unique opportunity to observe the abundance and species composition of macrofauna assemblages on unexploited reefs with high concentrations of mature oysters and undisturbed reef architecture. They might thus be used to better understand the magnitude of losses to reef dwelling macrofauna communities, and the associated loss of ecological functions resulting from reef destruction. We sampled reef macrofaunal assemblages on restored plots at four restored oyster reefs and adjacent non-restored plots located outside restored boundaries. We then compared the effects of study site location, and habitat quality (restored versus non-restored) on macrofaunal density using thirteen response variables. Density of macrofauna was an order of magnitude higher on restored reefs, epifaunal density was more than twice as high on restored reefs and sessile macrofaunal density was two orders of magnitude higher on restored reefs. Three out of the five dominant taxonomic groups were much more abundant on restored plots. Mean amphipod density was 20 times higher on restored plots and densities of xanthid crabs and demersal fish were both four times greater on restored plots. Two out of four functional feeding groups: suspension feeders and carnivore/omnivores, were more abundant on restored plots. Since reef macrofauna include many important fish prey species, oyster reef restoration may have the potential to augment fish production by increasing fish prey densities and fish foraging efficiency.