Marine heatwaves caused by global warming are progressively degrading coral reefs worldwide via the process of coral bleaching – the expulsion of photosynthetic endosymbionts. However, coral bleaching is not spatially homogeneous, but varies across environmental gradients in association with local conditions and taxonomic composition. Emerging evidence suggests that mangrove habitats are recurrent ‘'microenvironments' for reef corals, providing key biogeochemical services believed to influence their resilience, and housing co-tolerant coral taxa. This close association between coral reefs and mangroves has led to the hypothesis that the extent of coral bleaching is reduced by the proximity of reef building corals to mangroves. Here, we present the first global-scale test addressing this hypothesis. Using Bayesian generalised linear mixed effect modelling, we show that coral bleaching tends to increase under higher thermal stress when corals are further away from mangroves. When comparing conditional effects, corals furthest away from mangroves also show the highest levels of bleaching, suggesting a phenomenon of reduced bleaching for corals residing closer to mangroves under thermal stress. The drivers of this pattern may be numerous, but most likely include the presence of co-tolerant coral species which are known to be associated with mangroves. Future research should focus on disentangling the mechanisms underlying these coral bleaching patterns in association with mangroves, specifically focusing on in-situ environmental and taxonomic data collection. These endeavours will most likely require high-resolution analyses of coral reefs at more local-scales. Ultimately, our findings add to the ever-growing importance of mangroves for near-shore coral reef environments, and suggest a potentially important benefit for coral reefs associated with mangroves in the Anthropocene.

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全球变暖下与红树林环境相关的珊瑚白化模式的全球分析

全球变暖引起的海洋热浪正在通过珊瑚白化过程——光合内共生体的排出——逐渐退化全世界的珊瑚礁。然而，珊瑚白化在空间上并不均匀，而是因与当地条件和分类组成相关的环境梯度而异。新出现的证据表明，红树林栖息地是珊瑚礁反复出现的“微环境”，提供据信会影响其恢复力的关键生物地球化学服务，并容纳共同耐受的珊瑚类群。珊瑚礁和红树林之间的这种密切联系导致了这样一种假设，即造礁珊瑚靠近红树林会减少珊瑚白化的程度。在这里，我们提出了针对这一假设的第一个全球规模测试。使用贝叶斯广义线性混合效应模型，我们表明当珊瑚远离红树林时，珊瑚白化在较高的热应力下趋于增加。在比较条件效应时，离红树林最远的珊瑚也表现出最高水平的白化，这表明在热应力下靠近红树林的珊瑚存在白化减少的现象。这种模式的驱动因素可能很多，但最有可能包括已知与红树林相关的共耐受珊瑚物种的存在。未来的研究应侧重于理清这些与红树林相关的珊瑚白化模式背后的机制，特别是关注原位环境和分类学数据收集。这些努力很可能需要在更多局部尺度上对珊瑚礁进行高分辨率分析。最终，我们的发现增加了红树林对近岸珊瑚礁环境日益增长的重要性，并表明在人类世与红树林相关的珊瑚礁具有潜在的重要益处。