Supporting resilience-based coral reef management using broadscale threshold approaches

Area of Science:

• Marine Biology
• Ecosystem Management
• Conservation Science

Background:

• Resilience-Based Management (RBM) is crucial for coral reef health.
• Identifying resilience indicators and ecological thresholds is vital for effective reef management.
• Broadscale thresholds offer a benchmark for assessing reef condition in data-limited areas.

Purpose of the Study:

• To assess the resilience of coral reefs at Aldabra Atoll using broadscale thresholds.
• To synthesize reef condition data into a resilience index and classify management strategies.
• To evaluate coral cover changes and recovery post-bleaching in relation to resilience scores.

Main Methods:

• Collected data on structural complexity, fish biomass, herbivore biomass, juvenile coral density, and trophic-level fish biomass.
• Compared local data against broadscale thresholds to assess reef condition.
• Calculated a resilience index and classified sites using a reef management framework.
• Monitored coral cover changes from 2016 to 2022 to track recovery.

Main Results:

• Seven of eight seaward reefs at Aldabra Atoll exhibited expected resilience for a remote marine reserve.
• The local research station had minimal negative impact on reef resilience.
• Resilience scores correlated with observed coral cover changes and recovery patterns post-bleaching.

Conclusions:

• Aldabra Atoll's reefs demonstrate high resilience, indicating effective management.
• Broadscale thresholds are valuable tools for assessing reef resilience, even in remote locations.
• Future assessments can be improved by expanding threshold categories and incorporating site-specific factors.