The contribution of corals to reef structural complexity in Kāne‘ohe Bay

Abstract

The structural complexity of coral reefs provides important ecosystem functions, such as wave attenuation for coastal protection, surfaces for coral growth, and habitat for other organisms. Corals build much of this structure, but an understanding of how colonies of different species and sizes contribute to complexity is lacking. We quantified three interdependent descriptors of complexity-rugosity, fractal dimension, and height range-for reef patches as well as the corals growing upon them in Ka ¯ne'ohe Bay (O'ahu, Hawai'i). Despite similar levels of reef-scale complexity throughout the bay, we found marked differences in how species contribute to this complexity. Variation in complexity among species was closely tied to colony morphology, but not to colony size. Together, our results show that no one species is sufficient to generate the full spectrum of habitat complexities we see on coral reefs, which has direct implications for reef recovery and restoration.

Prediction of habitat complexity using a trait-based approach on coral reefs in Guam

“…S8 and S9). This is consistent with a recent study in Oahu, Hawaii where the associations between structural complexity and specific coral species were found to be closely tied to species morphology 59 . Millepora , on the other hand, exhibited some variability in both sizes and morphologies, but they lacked small colonies (i.e., 0–5 cm in size, Fig S5).…”

Characterizing canopy complexity of natural and restored intertidal oyster reefs (Crassostrea virginica) with a novel laser‐scanning method

“…For example, rugosity indices on study reefs (range: 1.0–2.2) agreed well with those reported by Karp et al (2018), Margiotta et al (2016), and Rodney and Paynter (2006), who measured linear rugosity indices between 1.2 and 3.0 on restored and relic oyster reefs. On the other hand, the intertidal oyster reefs investigated in the current study were markedly different than corals reefs, with prior studies reporting higher rugosity indices (Knudby & LeDrew 2007: 1–2.25; Burns et al 2015: 1.5; Yanovski et al 2017: 2.22; Carlot et al 2020: 2–3.75) and lower fractal dimensions (Zawada et al 2010: 2–2.5; Leon et al 2015: 2.2–2.6; Miller et al 2021: 2–2.5) for corals in comparison to oysters ( = 1.2–1.5; = 2.67–2.74). Differences in roughness characteristics between corals and oysters may be due, at least in part, to differences in reef growth and development.…”

“…manual measurements of other natural marine canopies, including coral reefs (Knudby & LeDrew 2007;Leon et al 2015;Miller et al 2021), mussel beds (Commito & Rusignuolo 2000;Lim et al 2020), and oyster reefs (Margiotta et al 2016;Karp et al 2018). Although direct comparisons are complicated by variable measurement techniques, which can have significant effects on inferred surface complexity (Knudby & LeDrew 2007;Yanovski et al 2017), it is still useful to place the results of this study in the broader context of marine canopy literature.…”

Fine-scale variability in coral bleaching and mortality during a marine heatwave

“…Fractal dimension and rugosity capture different elements of complexity on a reef and might work in asynchronous ways to affect processes like bleaching and mortality (Torres-Pulliza et al, 2020). While coral diversity in Kāne‘ohe Bay is low, species exist in a range of morphotypes and contribute differently to overall reef structure (Miller et al, 2021). While we did not detect changes in the 3D complexity of reefs one year post-bleaching, further monitoring will provide insight into how reef-scale R and D change as corals of different species grow, recover, or die.…”