Table_2_Coral reef resilience persisted for a millennium but has declined rapidly in recent decades.xls

The lack of long-term records of coral community composition restricts our understanding of the contemporary ecological states of tropical reefs. Here we integrated paleo-ecological reconstruction, historical mortality evidence, and ecological survey data to determine the temporal variability in reef resilience of the Nansha atolls in the tropical western Pacific. Subfossil coral assemblages extracted from the reef cores exhibited no evidence of community shifts attributable to centennial-scale changes in El Niño variability during the last millennium, suggesting long-term stability in community structure and persistence of reef resilience. By contrast, ecological surveys revealed a major collapse in the reef ecosystem, and high-precision U-series dating of dead Acropora fragments indicated that this collapse occurred in recent decades and was especially relevant to several strong/extreme El Niño episodes. Frequent and intensive El Niño−Southern Oscillation and marine heatwaves have overwhelmed the reefs’ resistive and recovery capacity, thereby impairing reef resilience.

珊瑚群落组成的长期记录缺失，限制了我们对热带珊瑚礁当代生态状态的认知。本研究整合古生态重建（paleo-ecological reconstruction）、历史珊瑚死亡证据与生态调查数据，旨在探究热带西太平洋南沙环礁的珊瑚礁恢复力时间变异性。从礁岩芯中获取的亚化石珊瑚组合（subfossil coral assemblages）未显示出近千年来因厄尔尼诺变率百年尺度变化所引发的群落结构转变迹象，表明群落结构长期稳定且珊瑚礁恢复力持续存在。与之形成鲜明对比的是，生态调查显示珊瑚礁生态系统发生了大规模崩溃；对死亡鹿角珊瑚（Acropora）碎片的高精度铀系测年（U-series dating）结果表明，此次崩溃发生于近数十年间，且与多次强/极端厄尔尼诺事件密切相关。频发且高强度的厄尔尼诺-南方涛动（El Niño−Southern Oscillation）与海洋热浪已远超珊瑚礁的抵抗与恢复能力，进而削弱了其恢复力。