Damaged coral reefs show slower than expected recovery for up to six years before switching to a faster phase of regrowth, according to new research.
A young coral colony (Acropora recruit) on the surface of a reef on the Great Barrier Reef.
Understanding the recovery dynamics of corals is paramount to enabling the effective management of coral reefs. While detailed mechanistic models provide insight into reef recovery patterns, colony scale monitoring is not viable for reefs over a large geographical extent, such as the Great Barrier Reef (GBR).
But by modifying data analysis methods used in cancer cell biology on long-term monitoring data, researchers were able to pinpoint patterns of reef recovery amid disturbances including storms, marine heatwaves, and crown-of-thorns starfish.
Two-phase recovery pattern
The researchers found that a two-phase recovery pattern was present in 50 to 60 percent of the monitored sites on the GBR that had experienced at least one major disturbance over the past 30 years.
It has been assumed that the main driver of reef recovery was competition for space, but these results suggest that coral colonies may be growing at lower rates for three to four years after major disturbances before normal growth rates set in again.
Consequently, if there are less than five years between major disturbances, reefs exhibiting two-phase growth are never likely to reach 15 percent cover. This has serious implications for recovery potential, as major disturbances are bound to occur more frequently due to climate change.
This analysis has provided critical information for the management of the GBR, as it identified reefs in need of help, in the same way doctors triage patients to prioritise treatment.
