Managing for systemic resilience in coral reef systems and marine reserves

Individual reefs in coral reef systems are exposed to different levels of disturbance impacts. This spatial heterogeneity of exposure patterns will result in, sometimes temporary, refugia that can support the recovery of coral... [ view full abstract ]

Individual reefs in coral reef systems are exposed to different levels of disturbance impacts. This spatial heterogeneity of exposure patterns will result in, sometimes temporary, refugia that can support the recovery of coral populations on affected reefs through connectivity. Combining individual source-sink relationships into a system-level connectivity network highlights reefs with the highest potential to support regional recovery processes. Ideally, such reefs will have not only high replenishment potential but also preserved adult stocks due to low exposure. The presence of such reefs will make the whole system resilient, as the potential for recovery could persist even after large portions of the system have been affected. Here we use Australia’s Great Barrier Reef as an example to show how such an analysis can be performed. We also address the challenges inherent in such prioritisation, chiefly the need to account for spatiotemporal changes in disturbance patterns, especially as the disturbance impacts become more intense and unpredictable with climate change. Moreover, variability in connectivity patterns can leave critical sources vulnerable to not only increasing exposure, but also to recovery setbacks due to loss of upstream connectivity. Ecosystem and connectivity models therefore need to capture these dynamic processes in order to inform management decisions that aim to prioritise reefs for their role in maintaining systemic resilience. These principles can also be applied to not only conservation and planning marine reserves under climate change, but also to guide restoration efforts, manage spatially explicit fisheries, and detect potential regime shifts.