Future climate warming threatens coral reef function on World Heritage reefs

Area of Science:

• Marine ecology
• Climate change science
• Conservation biology

Background:

• Climate change poses a severe threat to marine World Heritage sites.
• Ocean warming has already caused significant damage to marine ecosystems like coral reefs, kelp forests, and seagrass meadows.

Purpose of the Study:

• To project future declines in species and ecosystem functions across Australia's four World Heritage coral reef regions under different warming scenarios.
• To identify key functional differences and forecast changes in reef functions over time.

Main Methods:

• Combined model simulations of species abundance and ecological persistence with trait space reconstructions.
• Analyzed data for present-day conditions, 2050 (+1.5°C warming), and 2100 (+2°C warming).
• Assessed biogeographical overlaps and functional changes across four Australian World Heritage coral reef regions.

Main Results:

• By 2050, approximately 40% of the Great Barrier Reef may exceed critical thermal thresholds, leading to mortality.
• A 1.5°C warming scenario is projected to cause a 20.2% decline in species richness (around 70 extinctions) and loss of functions across all studied reefs.
• A 2°C warming scenario predicts a complete collapse of ecosystem functions, aligning with Intergovernmental Panel on Climate Change (IPCC) forecasts.

Conclusions:

• Regional climate change impacts and reef vulnerabilities vary, demanding bespoke management approaches.
• Understanding species and functional responses is crucial for setting biodiversity targets and guiding conservation efforts for these priority reefs.
• Identifying 'winners' and 'losers' in future reef configurations is essential for achieving global biodiversity goals.