Data from: Patterns of oyster recruitment and habitat provision across tidal elevation gradients are dependent on predator mitigation methods

For restoration projects conducted in environments with strong predation,
effective predator mitigation can be key to the successful recruitment of
habitat-forming species, and the development of associated ecological
communities. Predator mitigation may involve exclusion through caging, or
the provision of protective spaces through complex habitat mimics. The
relative efficacy of the two approaches may vary across environmental
gradients, according to predation and environmental stress. To inform the
most effective predator mitigation methods for oyster reef restoration, we
compared oyster recruitment and associated community development between
uncaged concrete blocks, caged concrete blocks and biodegradable complex
habitat mimics (BESE), across 3 tidal elevations and 3 sites in eastern
Australia. After one year, oyster and associated invertebrate recruitment
to uncaged concrete was low at all sites and tidal elevations. Whereas
BESE supported greater invertebrate abundance and richness than caged
concrete blocks at all elevations, the relative performance of the two
predator mitigation methods in facilitating oyster recruitment was
spatially variable.  In the subtidal, BESE were less effective at
excluding small-bodied mesopredatory fishes than caged concrete units and
supported less oyster recruitment. In the intertidal, where exposure to
mesopredatory fish is less due to emersion at low tide, there was greater
recruitment to BESE than to caged concrete. Synthesis and applications:
The effectiveness of predator mitigation methods used in oyster reef
restoration can vary across small-scale gradients. Understanding the
strength of predator-prey interactions at local scales, and the identity
of key predators, is crucial for designing restoration methods that allow
colonisation of target species and exclude key predators.