Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium
Climate change is exacerbating shoreline erosion and flooding, posing significant risks to coastal communities. Although traditional coastal defenses such as seawalls, dykes, and breakwaters offer protection from these hazards, their high environmental and economic costs are driving interest in cost...
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Elsevier
2024-12-01
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| Series: | Nature-Based Solutions |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S277241152400065X |
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| author | Stephan A Bitterwolf Borja G Reguero Curt D Storlazzi Michael W Beck |
| author_facet | Stephan A Bitterwolf Borja G Reguero Curt D Storlazzi Michael W Beck |
| author_sort | Stephan A Bitterwolf |
| collection | DOAJ |
| description | Climate change is exacerbating shoreline erosion and flooding, posing significant risks to coastal communities. Although traditional coastal defenses such as seawalls, dykes, and breakwaters offer protection from these hazards, their high environmental and economic costs are driving interest in cost-competitive nature-based solutions. Coral reef restoration is a nature-based solution that may be particularly apt to mitigate tropical coastal flooding and shoreline erosion while providing benefits to local tourism, fisheries, and nature. However, the novelty of this field requires studies demonstrating the benefits of reefs for coastal protection. While the flood protection benefits of reefs have been well-documented, their effects on shoreline erosion are comparatively less understood. Here, we investigate the effects of coral reefs on shoreline erosion by comparing tropical beach responses at short and long timescales, as well as identifying important reef structural features influencing coastal erosion rates. Our analyses leveraged two key datasets created in this study: the first derived from a literature review on short-term shoreline erosion due to storm events, and another compiling >80 years of long-term erosion rates, bathymetry, habitat, and wave energy for the Hawaiian Islands of Kauaʻi, Oʻahu, and Maui. Our analyses reveal three key findings regarding the effects of reefs on shoreline erosion. Firstly, we find evidence for the role of reefs in mitigating shoreline erosion during storm events, with coral reef-protected beaches experiencing 97 % less beach volume loss than unprotected beaches. Secondly, a linear regression analysis demonstrates that coral reef structure and wave energy are important predictors of long-term shoreline erosion rates, explaining 34 % of the variation across the Hawaiian Islands. Consistent with prior research, we find beaches protected by coral reefs with shallow reef crests, wide reef flats, calmer offshore conditions, and positioned farther from the shore exhibit lower erosion rates than others. Finally, when comparing historical erosion rates of protected and unprotected beaches in Hawai'i, we find a seemingly incongruous pattern where coral reef-protected beaches eroded up to 2x faster than beaches without reefs. While the cause of the enhanced erosion is yet to be fully understood, a combination of coral reef structural degradation and sea-level rise is likely shifting the equilibrium profiles of reef-protected beaches inshore. These results emphasize the role of coral reefs in reducing coastal erosion during storm events while revealing contrasting erosion patterns over long timescales. Future studies would ideally broaden the scope to include various regions, utilize advanced sediment transport models, and undertake field experiments to deepen our understanding of coral reef-coupled shoreline dynamics. |
| format | Article |
| id | doaj-art-dc69f085bd6f46239d5a3f8ddf162c8a |
| institution | OA Journals |
| issn | 2772-4115 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Elsevier |
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| series | Nature-Based Solutions |
| spelling | doaj-art-dc69f085bd6f46239d5a3f8ddf162c8a2025-08-20T02:36:35ZengElsevierNature-Based Solutions2772-41152024-12-01610017410.1016/j.nbsj.2024.100174Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibriumStephan A Bitterwolf0Borja G Reguero1Curt D Storlazzi2Michael W Beck3Center for Coastal Climate Resilience, University of California Santa Cruz, Santa Cruz, CA, USA; Corresponding author.Center for Coastal Climate Resilience, University of California Santa Cruz, Santa Cruz, CA, USA; Coastal Science and Policy, University of California Santa Cruz, Santa Cruz, CA, USAU.S. Geological Survey, Pacific Coastal and Marine Science Center, 2885 Mission Street, Santa Cruz, CA 95060, USACenter for Coastal Climate Resilience, University of California Santa Cruz, Santa Cruz, CA, USAClimate change is exacerbating shoreline erosion and flooding, posing significant risks to coastal communities. Although traditional coastal defenses such as seawalls, dykes, and breakwaters offer protection from these hazards, their high environmental and economic costs are driving interest in cost-competitive nature-based solutions. Coral reef restoration is a nature-based solution that may be particularly apt to mitigate tropical coastal flooding and shoreline erosion while providing benefits to local tourism, fisheries, and nature. However, the novelty of this field requires studies demonstrating the benefits of reefs for coastal protection. While the flood protection benefits of reefs have been well-documented, their effects on shoreline erosion are comparatively less understood. Here, we investigate the effects of coral reefs on shoreline erosion by comparing tropical beach responses at short and long timescales, as well as identifying important reef structural features influencing coastal erosion rates. Our analyses leveraged two key datasets created in this study: the first derived from a literature review on short-term shoreline erosion due to storm events, and another compiling >80 years of long-term erosion rates, bathymetry, habitat, and wave energy for the Hawaiian Islands of Kauaʻi, Oʻahu, and Maui. Our analyses reveal three key findings regarding the effects of reefs on shoreline erosion. Firstly, we find evidence for the role of reefs in mitigating shoreline erosion during storm events, with coral reef-protected beaches experiencing 97 % less beach volume loss than unprotected beaches. Secondly, a linear regression analysis demonstrates that coral reef structure and wave energy are important predictors of long-term shoreline erosion rates, explaining 34 % of the variation across the Hawaiian Islands. Consistent with prior research, we find beaches protected by coral reefs with shallow reef crests, wide reef flats, calmer offshore conditions, and positioned farther from the shore exhibit lower erosion rates than others. Finally, when comparing historical erosion rates of protected and unprotected beaches in Hawai'i, we find a seemingly incongruous pattern where coral reef-protected beaches eroded up to 2x faster than beaches without reefs. While the cause of the enhanced erosion is yet to be fully understood, a combination of coral reef structural degradation and sea-level rise is likely shifting the equilibrium profiles of reef-protected beaches inshore. These results emphasize the role of coral reefs in reducing coastal erosion during storm events while revealing contrasting erosion patterns over long timescales. Future studies would ideally broaden the scope to include various regions, utilize advanced sediment transport models, and undertake field experiments to deepen our understanding of coral reef-coupled shoreline dynamics.http://www.sciencedirect.com/science/article/pii/S277241152400065XCoral reefShoreline erosionBeach storm responseCoastal Buffering EcosystemNbSReef Restoration |
| spellingShingle | Stephan A Bitterwolf Borja G Reguero Curt D Storlazzi Michael W Beck Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium Nature-Based Solutions Coral reef Shoreline erosion Beach storm response Coastal Buffering Ecosystem NbS Reef Restoration |
| title | Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium |
| title_full | Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium |
| title_fullStr | Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium |
| title_full_unstemmed | Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium |
| title_short | Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium |
| title_sort | shifting sands the influence of coral reefs on shoreline erosion from short term storm protection to long term disequilibrium |
| topic | Coral reef Shoreline erosion Beach storm response Coastal Buffering Ecosystem NbS Reef Restoration |
| url | http://www.sciencedirect.com/science/article/pii/S277241152400065X |
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