Australian Institute of Marine Science, PMB No.3, Townsville, Queensland, 4810, Australia.
Glob Chang Biol. 2017 Apr;23(4):1511-1524. doi: 10.1111/gcb.13593. Epub 2017 Jan 31.
Ocean warming under climate change threatens coral reefs directly, through fatal heat stress to corals and indirectly, by boosting the energy of cyclones that cause coral destruction and loss of associated organisms. Although cyclone frequency is unlikely to rise, cyclone intensity is predicted to increase globally, causing more frequent occurrences of the most destructive cyclones with potentially severe consequences for coral reef ecosystems. While increasing heat stress is considered a pervasive risk to coral reefs, quantitative estimates of threats from cyclone intensification are lacking due to limited data on cyclone impacts to inform projections. Here, using extensive data from Australia's Great Barrier Reef (GBR), we show that increases in cyclone intensity predicted for this century are sufficient to greatly accelerate coral reef degradation. Coral losses on the outer GBR were small, localized and offset by gains on undisturbed reefs for more than a decade, despite numerous cyclones and periods of record heat stress, until three unusually intense cyclones over 5 years drove coral cover to record lows over >1500 km. Ecological damage was particularly severe in the central-southern region where 68% of coral cover was destroyed over >1000 km, forcing record declines in the species richness and abundance of associated fish communities, with many local extirpations. Four years later, recovery of average coral cover was relatively slow and there were further declines in fish species richness and abundance. Slow recovery of community diversity appears likely from such a degraded starting point. Highly unusual characteristics of two of the cyclones, aside from high intensity, inflated the extent of severe ecological damage that would more typically have occurred over 100s of km. Modelling published predictions of future cyclone activity, the likelihood of more intense cyclones within time frames of coral recovery by mid-century poses a global threat to coral reefs and dependent societies.
气候变化导致海洋变暖，直接威胁珊瑚礁，使珊瑚礁因致命的热压力而死亡，并间接地通过增强引发珊瑚礁破坏和相关生物丧失的飓风能量来威胁珊瑚礁。尽管飓风频率不太可能增加，但全球范围内预测飓风强度将会增加，导致最具破坏性的飓风更频繁地发生，这可能对珊瑚礁生态系统造成严重后果。虽然不断增加的热压力被认为是珊瑚礁的普遍风险，但由于有关飓风对珊瑚礁影响的数据有限，无法进行预测，因此缺乏关于飓风强化威胁的定量估计。在这里，我们利用澳大利亚大堡礁（GBR）的广泛数据表明，本世纪预测的飓风强度增加足以极大地加速珊瑚礁退化。尽管经历了多次飓风和创纪录的热浪，但由于不断有新的珊瑚礁形成，以及未受干扰的珊瑚礁面积增加，因此在过去十年中，外大堡礁的珊瑚礁损失很小，且局限于局部地区，直到过去 5 年里发生了三次异常强烈的飓风，导致珊瑚覆盖率降至创纪录的低值，超过 1500 公里。在中部和南部地区，生态破坏尤其严重，超过 1000 公里的珊瑚覆盖率被破坏了 68%，迫使相关鱼类群落的物种丰富度和丰度出现创纪录的下降，许多地方的鱼类已灭绝。四年后，珊瑚覆盖率的平均恢复速度相对较慢，鱼类物种丰富度和丰度进一步下降。珊瑚礁从如此严重的退化起点恢复，其多样性的恢复速度可能会很慢。除了强度高之外，两次飓风中的两次异常特征使严重生态破坏的范围扩大，而这种破坏通常会在超过 100 公里的范围内发生。对未来飓风活动的预测模型，以及在本世纪中叶珊瑚礁恢复时间框架内发生更强烈飓风的可能性，对珊瑚礁和依赖珊瑚礁的社会构成了全球性威胁。
