Drake Matilde A, Noonan Sam H C, Alvarez-Noriega Mariana, Rashid Ahmad R, Fabricius Katharina E
Australian Institute of Marine Science, Townsville, Australia.
James Cook University, Townsville, Australia.
PLoS One. 2025 Mar 26;20(3):e0319521. doi: 10.1371/journal.pone.0319521. eCollection 2025.
Coral reefs worldwide are experiencing frequent disturbances, rendering coral recruitment critical for population recovery. This large-scale study identifies environmental, spatial, and biotic drivers of coral recruit densities at 141 stations stratified across seven regions and three depths (1, 5, and 15 m depths) with contrasting environmental conditions across and along the Great Barrier Reef and the Torres Strait. Settlement tiles were deployed for two years, with coral densities and benthic cover quantified following retrieval. Benthic communities were assessed from tile images using the point-classification AI program ReefCloud. Environmental data were derived from in situ readings and environmental models. Across all sites, coral recruit densities averaged 187 ± 12 m‒2 (SE), with region-wide averages ranging from 43.5 ± 12 m‒2 to 247 ± 32 m‒2. Mean densities were 3-fold higher in the four clear-water regions compared to the three turbid-water regions. Boosted regression tree analyses showed that densities declined with increasing current velocity, sedimentation, and depth, and increased with increasing pH. From lowest to highest observed levels of current velocity, recruit densities declined by ~ 530 m‒2. From lowest to highest sedimentation, densities declined by ~ 300 recruits m‒2. Even relatively minor increases in sediment deposits from 0.1 to 38 mg cm‒2 were associated with a monotonic decline of ~ 130 recruits m‒2. Recruit densities were also weakly positively related to the cover of turf and crustose coralline algae on tile tops, and negatively related to fleshy invertebrate cover on the tile undersides. Some variation in the cover of these benthic taxa was also related to environmental conditions (e.g., sedimentation and currents), suggesting the possibility of additional indirect environmental effects on recruit densities. Our results highlight the strong role of current velocity and water quality as regulators of coral recruitment success, likely influencing the capacity of reef sites to recover after a disturbance.
全球珊瑚礁正频繁受到干扰，这使得珊瑚补充对种群恢复至关重要。这项大规模研究确定了在横跨大堡礁和托雷斯海峡的七个区域和三个深度（1米、5米和15米深度）分层设置的141个站点的珊瑚补充密度的环境、空间和生物驱动因素，这些区域的环境条件存在差异。放置定居瓦片两年，回收后对珊瑚密度和底栖生物覆盖度进行量化。使用点分类人工智能程序ReefCloud从瓦片图像评估底栖生物群落。环境数据来自现场读数和环境模型。在所有站点中，珊瑚补充密度平均为187±12 m⁻²（标准误），区域平均密度范围为43.5±12 m⁻²至247±32 m⁻²。四个清水区域的平均密度比三个浑水区域高3倍。增强回归树分析表明，密度随着流速、沉积和深度的增加而下降，随着pH值的增加而增加。从最低到最高观测流速水平，补充密度下降了约530 m⁻²。从最低到最高沉积水平，密度下降了约300个补充个体/m²。即使沉积物从0.1毫克/平方厘米相对小幅增加到38毫克/平方厘米，也会导致补充个体密度单调下降约130个补充个体/m²。补充密度也与瓦片顶部的草皮和硬壳珊瑚藻覆盖度呈弱正相关，与瓦片底部的肉质无脊椎动物覆盖度呈负相关。这些底栖生物类群覆盖度的一些变化也与环境条件（如沉积和水流）有关，这表明环境可能对补充密度产生额外的间接影响。我们的结果突出了流速和水质作为珊瑚补充成功调节因素的重要作用，可能影响珊瑚礁在受到干扰后恢复的能力。
