A decline in coral cover is expected under future climate conditions.
Three complementary interventions to manage this that are being researched and developed by the Reef Restoration and Adaptation Program (RRAP) are:
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Cooling and shading reefs at risk of bleaching (prevention)
Cooling and shading involves spraying fine water aerosols into the air to create fog or clouds to either shade reefs or reflect sunlight, cooling the area to reduce risk of coral bleaching.
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Rubble stabilisation on degraded reefs (to facilitate reef recovery)
Rubble stabilisation involves restoring damaged reef surfaces where dead or degraded corals have become loose or unconsolidated after a disturbance. This allows new corals to settle and grow.
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Re-seeding degraded reefs (to facilitate reef recovery and support future resilience).
Re-seeding involves mass- producing coral larvae in tanks or harvesting coral larvae from the wild, to re-populate degraded reefs or increase the number of corals in a reef.
ADRIA can help decision makers determine where, when, under what conditions, and how often these interventions should be deployed with effective deployment strategies and contingency plans.
Using the example of re-seeding corals, we want to avoid hazardous locations such as those that are too hot, or prone to cyclones. We also want to consider locations that are economically or culturally important and those that are well connected by tidal activity.
There are many other considerations we could include such as determining which coral species were necessary to underwrite the future of the coral reef, which offered the greatest ecosystem benefits, and which were most likely to survive the forecast conditions.
Given these parameters, the smart heuristics within ADRIA guides where these interventions would be best deployed.
To explore what might happen under the likely range of future conditions, we can ask ADRIA to run a set of model simulations with a simple coral ecosystem model that can predict coral cover under various scenarios.
Because of its simplicity, this model is quick to run (half a second or less per simulation) and these simulations can be run both with and without interventions under a wide variety of different environmental conditions.
We call these simulations ‘scenarios’, and we use these to ask ‘What if...?’. For example, what if temperatures become hotter much faster than we expected? What if we can't harvest as many corals as quickly as we expected? What if the efficacy of the interventions is not as high as we hoped? Or, what if it is more effective than we thought it would be?
We do this thousands of times, exploring as many scenarios and strategies as possible to gain an understanding of how we might best adapt to these uncertain futures.
We assess how well each strategy did across a range of environmental conditions, to discover which deployment strategies worked best across the widest range of plausible conditions and according to a range of measures. We describe these as being ‘robust’.
These scenario explorations and the robust pathways we discover help inform discussion on what outcomes are acceptable, or unacceptable, and under what conditions.
