Erosion is a key process in shaping the physical structure of coral reefs, yet due to erosion being semi‐cryptic and difficult to quantify, information remains limited. Here, we investigate erosional processes along Ningaloo Reef, an extensive fringing coral reef in Western Australia. We employed both direct and indirect methods to measure erosion in wave‐exposed reef slopes and protected lagoonal habitats. Direct measurements of erosion on coral blocks were among the highest found globally, with total erosion of 3.07 kg m−2 yr−1 (4% from micro, 0.6% from macro, and 94% from external), whilst indirect rates were estimated at 2.4 ± 0.20 kg m−2 yr−1 (78% from parrotfish, 22% from urchins). Indirect erosion rates were influenced by the species and size of parrotfish, with Chlorurus microrhinos removing 0.44 ± 0.19 kg m−2 yr−1 (22% of parrotfish erosion). Scanning electron microscopy and computed tomography show that micro and macroborer erosion contributions to direct erosion were low, most likely due to heavy grazing by parrotfish and the short deployment period of experimental substrates. A substantial portion of external erosion on blocks (0.53 ± 0.23 kg m−2 yr−1) could not be attributed to bioeroders and was poorly correlated with wave exposure, suggesting processes not quantified contribute to this unaccounted aspect of erosion. Our results confirm that bioerosion by parrotfish is especially significant at Ningaloo Reef, and large‐bodied individuals of C. microrhinos are key in conserving this key ecological process.

中文翻译：

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暴露在波浪中的边缘珊瑚礁的侵蚀率很高

侵蚀是塑造珊瑚礁物理结构的关键过程，但由于侵蚀是半神秘的且难以量化，信息仍然有限。在这里，我们调查了宁加洛礁 (Ningaloo Reef) 的侵蚀过程，宁加洛礁是西澳大利亚广阔的边缘珊瑚礁。我们采用直接和间接方法来测量暴露在波浪中的珊瑚礁斜坡和受保护的泻湖栖息地的侵蚀。对珊瑚块侵蚀的直接测量是全球发现的最高侵蚀之一，总侵蚀量为 3.07 kg m−2年−1（4% 来自微观，0.6% 来自宏观，94% 来自外部），而间接比率估计为 2.4 ± 0.20 kg m−2年−1（78% 来自鹦嘴鱼，22% 来自海胆）。间接侵蚀率受到鹦嘴鱼的种类和大小的影响，小犀牛去除 0.44 ± 0.19 kg·m−2年−1（鹦嘴鱼侵蚀的 22%）。扫描电子显微镜和计算机断层扫描表明，微型和大型蛀虫侵蚀对直接侵蚀的贡献较低，这很可能是由于鹦嘴鱼的大量吃草和实验基质的部署周期较短。块体外部侵蚀的很大一部分 (0.53 ± 0.23 kg m−2年−1）不能归因于生物侵蚀，并且与波浪暴露的相关性较差，这表明未量化的过程导致了侵蚀的这一未解释的方面。我们的结果证实，鹦嘴鱼的生物侵蚀在宁加洛礁 (Ningaloo Reef) 和体型较大的个体中尤其显着。C. 小犀牛是保护这一关键生态过程的关键。