Interacting effects of habitat forming species on key processes maintaining community structure

The appropriate design of restoration projects is contingent upon an understanding of the processes that influence and maintain biodiversity and key ecosystem functions. Along the east coast of Australia, there is growing... [ view full abstract ]

The appropriate design of restoration projects is contingent upon an understanding of the processes that influence and maintain biodiversity and key ecosystem functions. Along the east coast of Australia, there is growing interest in restoration of lost shellfish reefs, but our understanding of how oysters interact with other habitat forming species to influence biodiversity and key ecosystem functions remains poor. In mangrove forests, Sydney rock oysters, Saccostrea glomerata, may co-occur with the fucalean alga, Hormosira banksii. The alga may have positive, negative or neutral affects on the ability of the oyster to successfully recruit and protect invertebrates from predation and desiccation stress. Using fully factorial field and lab experiments, we assessed how the two habitat forming species interact to influence oyster recruitment and survival, as well as predator-prey interactions. We also assessed the density dependence of their interacting effects. By studying oyster recruitment and survival, and predator-prey interactions, this study addresses the mechanisms by which oyster restoration is likely to enhance biodiversity and the dependency of these effects on the presence or absence of a second habitat forming species, H. banksii.