Sedimentation and overfishing drive changes in early succession and coral recruitment (Palau, Micronesia)

Sedimentation and overfishing are important local stressors on coral reefs that can independently result in declines in coral recruitment and shifts to algal dominated states. However, the role of herbivory in driving recovery across environmental gradients is often unclear. Here we investigate early successional benthic communities and coral recruitment across a sediment gradient in Palau, Micronesia over a 12-month period. Total sedimentation rates measured by ‘TurfPods’ varied from 0.03 ± 0.1 SE mg cm-2 day-1 at offshore sites to 1.32 ± 0.2 mg cm-2 day-1 at inshore sites. To assess benthic succession, three-dimensional settlement tiles were deployed at sites with experimental cages used to exclude tile access to larger herbivorous fish. Benthic assemblages exhibited rapid transitions across the sediment gradient within 3 months of deployment. At low levels of sedimentation (< 0.6 mg cm-2 day-1), herbivory resulted in communities dominated by coral recruitment inducers (short turf ...