Decision support

In a warming world, coral reefs face unprecedented challenges.

While best-practice conventional management and reducing carbon emissions are essential; on their own, they are unlikely to be enough to sustain coral reefs in the face of continued climate change.

AIMS is working with scientists around the world to develop approaches that can help coral reefs remain resilient and sustain the values reefs provide.

Such approaches need guidance to ensure they can be effectively deployed to help coral reefs in an uncertain future.

AIMS’ Decision Support team is developing a suite of models and guidance systems to help environmental decision makers be informed when they balance priorities to optimise effort and outcomes.

How do we make the best-informed decisions?

Developing new technologies for environmental management carries risks, but delaying action represents lost opportunity to sustain coral reefs in a rapidly closing window.

Deciding where, when, and how to intervene – if at all – using new reef restoration and adaptation measures is challenging.

AIMS’ Decision Support team is developing tools to enable us to:

forecast the impact of the possible range of future temperature increases and other stressors on coral reefs
model how this would vary with the introduction of novel environmental management techniques – or interventions – and the effect of layering different interventions on reefs
identify where and how we are likely to get the most positive impact
adjust and fine-tune our actions as we have further information.

A text based image with blue water in the background. the text restates the dot points of the told being developed by AIMS' decision support team.

Adaptive Dynamic Reef Intervention Algorithms (ADRIA)

Models are simplified versions of reality to help us explore what might happen in the future.

As there is always uncertainty in the information available, there will always be a level of uncertainty in what models project.

For example, while experts have a good general idea of what conditions we will face in the future, we don't know exactly how hot it will get, how many cyclones we might have and how corals and reef ecosystems will react to those conditions.

To reduce uncertainty, AIMS has developed the Adaptive Dynamic Reef Interventions Algorithms (ADRIA) platform to provide an integrated approach to decision support in reef management.

It allows us to explore what might happen under a wide variety of conditions, deploying different combinations of novel interventions, using a range of models to consider and manage uncertainty.

The aim is to help risk managers and decision makers develop adaptive plans and policies that maximise ecological, economic, and social and cultural outcomes.

The team is currently identifying robust, strategic, and tactical intervention options in space and time under climate change for the Reef Restoration and Adaptation Program (RRAP).

Filling the knowledge gap

ADRIA also helps us recognise when conditions are shifting, so reef managers can develop plans and policies that are adaptive to changing conditions, to ensure they're better prepared.

Once we have a good idea of what strategies might work, we explore them further using different, more complex ecosystem models.

There is still much knowledge to be gained about coral reef ecosystems to inform ADRIA and reduce uncertainty. AIMS is leading significant research to help fill this knowledge gap.

Apart from modelling strategies to maximise coral cover, ADRIA can also be used to build capacity for other marine life and reef-related ecosystems. For example, we connect impacts of climate change on corals and seagrasses to consequences for fish and other marine species. We can then model how management actions might generate positive impacts to help sustain tropical marine ecosystems in the face of climate change and other stressors.

How ADRIA works

ADRIA consists of:

smart heuristics (shortcuts to make judgements and problem-solve)

and scenario exploration and analysis

ADRIA works in tandem with existing ecosystem models such as C~Scape, a coral life-cycle model developed at AIMS, and the University of Queensland’s ReefMod, which provides a whole of Great Barrier Reef simulation.

Case study: Guiding decision-making on reef interventions

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:

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.
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.
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.