Abstract A variety of techniques for measuring coral growth, a fundamental biological trait, have been used to improve our understanding of coral demographics. Remaining gaps and biases in this information, in combination with technological advances, led to the present study. We assessed the capacity of structure-from-motion (SfM) technology to build image mosaics (orthophotos) of ~6 × 8 m reef plots from which individual coral colonies could be identified in repeated annual surveys and colony planar area measured. We monitored Acropora, Pocilloporidae (specifically from the genera Stylophora and Seriatopora) and Platygyra colonies over 2 years. We compared growth measurements, as change in radius, from SfM orthophotos to the more traditional method of tagging and photographing individual coral colonies. We conclude that planar coral growth can be measured from SfM orthophotos, with clear advantages over tagging including large sample sizes, and speed and ease of surveying, albeit with some bias in the SfM method (growth estimates were 15% greater (~0.5 cm/year) from standard photos than from the SfM orthophotos). We documented mortality and growth rates in a high wave energy environment on the reef slope at Ningaloo Reef, Western Australia, where there were no existing coral growth or mortality estimates. The mean change in radial extension of Acropora colonies with no mortality was 2.92 ± 0.06 (SE, n = 572) cm year−1 across the pooled data set of standard and orthophotos, substantially lower than previous estimates on similar species from the region. The growth rate of Pocilloporidae was 3.54 ± 0.52 (SE, n = 12) cm year−1 for colonies with no mortality. Robust planar growth estimates were not obtained for Platygyra due to its morphology, but we report high survivorship of the colonies: 94% with no mortality as compared with 79% for Acropora and only 53% for Pocilloporidae. High sample sizes from the novel SfM methodology allowed us to demonstrate that Acropora growth rate was inversely linked to wave energy and coral size.

中文翻译：

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运动结构揭示珊瑚生长受西澳大利亚宁格鲁礁礁坡上的群体大小和波浪能的影响

摘要 测量珊瑚生长这一基本生物学特性的各种技术已被用于提高我们对珊瑚人口统计的理解。这些信息中的剩余差距和偏见，加上技术进步，导致了本研究。我们评估了运动结构 (SfM) 技术构建约 6 × 8 m 珊瑚礁地块的图像镶嵌（正射影像）的能力，在重复的年度调查和测量的殖民地平面面积中，可以从中识别出单个珊瑚群。我们监测了 Acropora、Pocilloporidae（特别是来自 Stylophora 和 Seriatopora 属）和 Platygyra 群落超过 2 年。我们比较了生长测量，如半径的变化，从 SfM 正射影像到更传统的标记和拍摄单个珊瑚群落的方法。我们得出结论，平面珊瑚生长可以从 SfM 正射影像测量，与标记相比具有明显的优势，包括大样本量、速度和调查的简便性，尽管在 SfM 方法中存在一些偏差（生长估计值高 15%（~0.5 cm/年）来自标准照片而不是来自 SfM 正射影像）。我们记录了西澳大利亚宁格鲁礁礁坡高波浪能环境中的死亡率和增长率，那里没有现有的珊瑚生长或死亡率估计值。在标准和正射影像的汇总数据集中，没有死亡的鹿角珊瑚群径向延伸的平均变化为 2.92 ± 0.06 (SE, n = 572) cm year-1，大大低于之前对该地区类似物种的估计。Pocilloporidae 的增长率为 3.54 ± 0.52 (SE, n = 12) cm year−1 对于没有死亡的菌落。由于其形态，Platygyra 没有获得可靠的平面生长估计值，但我们报告群体的高存活率：94% 没有死亡率，而 Acropora 为 79%，Pocilloporidae 仅为 53%。来自新颖 SfM 方法的高样本量使我们能够证明鹿角珊瑚的生长速度与波浪能和珊瑚大小成反比。