The influence of trophic interactions, habitat complexity, and landscape setting on community dynamics and restoration of oyster reefs

Debate over the prevalence of strong top predator effects such as trophic cascades within more complex and diverse terrestrial and marine systems continues to be a focal point of community ecology. However, integration of how habitat complexity influences predator-prey interactions and the strength of trophic cascades into effective management schemes of these systems remains limited. This disconnect between community ecology and ecosystem management hampers our ability to sustain ecosystem goods and services associated with intact habitats. Experimental manipulation of habitat complexity and predator regimes within oyster reef communities determined that habitat complexity disrupted or attenuated the strength of component interactions of atrophic cascade. Yet predator avoidance behavior by intermediate predators, mud crabs, reinforced the indirect benefit of toadfish on juvenile oysters, including on complex reefs where toadfish were ineffective at removing mud crabs. Restoration of oyster reef habitat was conducted to investigate the importance of reef presence, landscape setting, and temporal variability for interactions among predator fish, juvenile fish, and resident and transient invertebrates. Patterns of fish and resident invertebrate utilization of oyster reef habitat are largely influenced by the landscape setting in which a reef is located; therefore, managers conducting reef restoration should consider the ecological consequences of restoration site selection to insure provision of intended ecosystem goods and services. Finally, review of available data on fish densities on oyster reef and unstructured bottom habitats was used to quantify the amount of augmented fish production created per unit area of restored oyster reef habitat. This set of analyses and calculations revealed that every 10 m2 of newly constructed oyster reef in the southeast United States is expected to yield a benefit of an additional 2.6 kg of production of fish and large mobile crustaceans per year for the functional lifetime of the reef. Applying the findings of empirical investigations to our understanding of ecological systems and developing methods to quantify ecosystem functions will augment the efficiency with which habitat restoration efforts recover and sustain important ecosystem goods and services.