Natural selection could determine whether Acropora corals persist under expected climate change

Area of Science:

• Marine Biology
• Climate Change Science
• Evolutionary Biology

Background:

• Marine heatwaves are increasing in frequency and intensity due to climate change.
• Reef-building corals face mass mortality and strong selective pressures from these events.
• The capacity for coral adaptation to keep pace with warming remains uncertain.

Purpose of the Study:

• To investigate the potential for adaptation in Acropora corals under climate change.
• To model the eco-evolutionary dynamics of coral metapopulations facing marine heatwaves.
• To project the future persistence of coral populations and reef functioning.

Main Methods:

• Developed an eco-evolutionary metapopulation model for Acropora corals.
• Simulated population dynamics under various global warming scenarios.
• Assessed the role of natural selection in coral adaptation to thermal stress.

Main Results:

• Acropora corals possess some capacity for adaptation.
• Significant heatwave-induced population declines are projected in the coming decades.
• Under a ~3°C warming scenario, populations may persist but in depleted states with high extinction risk and potential loss of ecosystem function.

Conclusions:

• Coral adaptation alone is insufficient to maintain reef functioning under projected warming.
• Limiting global warming to 2°C through rapid greenhouse gas emission reductions is critical for coral survival beyond 2050.
• Urgent climate action is necessary to prevent severe losses in thermally sensitive coral populations and preserve reef ecosystems.