Reefs Protect Shorelines During Storms

The study highlights the vital protective role that coral reefs play in safeguarding tropical beaches from erosion during storm events. Beaches shielded by coral reefs experienced 97% less beach volume loss compared to those without such protection. This finding underscores the importance of healthy coral reefs in mitigating both the destructive effects of storms—which are becoming increasingly frequent and intense due to climate change—and long-term coastal erosion.

Long-Term Erosion: A Complex Picture

While reefs offer short-term shoreline protection during storms, the study's long-term analyses present a more nuanced view. By examining more than 80 years of data on coastal erosion rates, bathymetry, habitat, and wave energy across Kauaʻi, Oʻahu, and Maui, researchers found that coral reef structure and wave energy significantly influence long-term shoreline erosion. Specifically, beaches protected by reefs with shallow reef crests, wide reef flats, and calm offshore conditions tend to erode more slowly over time.

However, an unexpected pattern emerged when comparing historical erosion rates: coral reef-protected beaches sometimes erode up to twice as fast as their unprotected counterparts. The researchers suggest that this finding may be linked to the degradation of coral reef structures and rising sea levels, which are altering the natural equilibrium of these coastal environments.

Implications for Coastal Management

Coral reefs’ role in coastal erosion is complex and may require more nuanced management approaches. The researchers suggest that future studies should expand to other regions, employ advanced sediment transport models, and conduct field experiments to better understand the interplay between coral reefs and tropical shoreline dynamics.
 

Read the study, Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium, in Nature-Based Solutions.