Acute drivers influence recent inshore Great Barrier Reef dynamics

Area of Science:

• Marine Ecology
• Coral Reef Ecology
• Ecosystem Dynamics

Background:

• Coral reef research often overlooks turbid, inshore environments, despite their ecological significance.
• Inshore reefs near anthropogenic stressors are poorly understood compared to offshore Great Barrier Reef (GBR) systems.
• Habitat-forming organisms' dynamics are key to natural ecosystem management.

Purpose of the Study:

• To identify key drivers of coral cover dynamics in inshore Great Barrier Reef (GBR) ecosystems.
• To assess temporal trends in coral cover over 10 years using biological, environmental, and disturbance data.
• To compare inshore reef responses to known drivers of offshore reef degradation.

Main Methods:

• Utilized state-space models to analyze coral cover dynamics across 15 inshore reefs within six GBR catchments.
• Collected 10 years of biological, environmental, and disturbance data at two depths across 30 sites.
• Examined the influence of acute disturbance events and other ecological factors on coral cover trends.

Main Results:

• Nearly half (46%) of inshore reefs showed declining coral cover; others exhibited fluctuating, static, or positive trends.
• Storms were identified as the predominant driver of coral loss in the inshore GBR.
• Other factors like disease, juvenile coral density, and macroalgal cover varied in impact across catchments; flooding also negatively affected coral cover in some areas.

Conclusions:

• Inshore GBR reefs respond to disturbances similarly to offshore reefs, with acute events being major drivers.
• Storms are the most significant threat to inshore coral reefs, necessitating targeted management strategies.
• Further research is needed to elucidate the indirect mechanisms linking flooding to coral cover decline in these systems.