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Abstract AimHabitat complexity plays an important role in the structure and function of ecosystems worldwide. On coral reefs, habitat complexity influences ecosystem services such as harvestable fish biomass and attenuation of wave energy. Here, we test how three descriptors of surface complexity—rugosity, fractal dimension, and height range—trend with the geological age of reefs (0.2–5.1 million years old), depth (1–25 m), wave exposure (1–306 kW/m), coral cover (0–80%), and three habitat types (aggregated reef, rock and boulder, and pavement). LocationWe surveyed across 234 sites and 4 degrees of latitude in the eight main Hawaiian Islands. Time PeriodApril 2019 – July 2019. Major Taxa StudiedReef building corals. MethodsWe estimate three surface descriptors (rugosity, fractal dimension and height range) using structure‐from‐motion photogrammetry. We evaluate hypothesized relationships between these descriptors and geological reef age, depth, wave exposure, coral cover and reef habitat type using generalized linear models that account for survey design. ResultsThe rugosity of reef habitats decreased with geological reef age; fractal dimension (and coral cover) decreased with wave exposure; and height range decreased with depth. Variations in these patterns were explained by the different habitat types and the way they are formed over time. Nonetheless, the three surface descriptors were geometrically constrained across all habitat types, and so habitats occupied distinctly different regions of habitat complexity space. Main ConclusionsThis study showed how broad environmental characteristics influence the structural complexity of habitats, and therefore geodiversity, which is an important first step toward understanding the communities supported by these habitats and their ecosystem services.
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Coral reef structural complexity loss exposes coastlines to waves
Abstract Coral reefs offer natural coastal protection by attenuating incoming waves. Here we combine unique coral disturbance-recovery observations with hydrodynamic models to quantify how structural complexity dissipates incoming wave energy. We find that if the structural complexity of healthy coral reefs conditions is halved, extreme wave run-up heights that occur once in a 100-years will become 50 times more frequent, threatening reef-backed coastal communities with increased waves, erosion, and flooding.
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- Award ID(s):
- 2224354
- PAR ID:
- 10394148
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 13
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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