Speare Kelly E, Enright Lauren N, Aplin Allison, Adam Thomas C, Edmunds Peter J, Burkepile Deron E
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, USA.
School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, Arizona, USA.
Ecology. 2025 Jan;106(1):e4510. doi: 10.1002/ecy.4510.
Understanding how foundation species recover from disturbances is key for predicting the future of ecosystems in the Anthropocene. Coral reefs are dynamic ecosystems that can undergo rapid declines in coral abundance following disturbances. Understanding why some reefs recover quickly from these disturbances whereas others recover slowly (or not at all) gives insight into the drivers of community resilience. From 2006 to 2010 coral reefs on the fore reef of Moorea, French Polynesia, experienced severe disturbances that reduced coral cover from ~46% in 2005 to <1% in 2010. Following these disturbances, coral cover increased from 2010 to 2018. Although there was a rapid and widespread recovery of corals, reefs at 17 m depth recovered more slowly than reefs at 10 m depth. We investigated the drivers of different rates of coral recovery between depths from 2010 to 2018 using a combination of time-series data on coral recruitment, density, growth, and mortality in addition to field experiments testing for the effects of predation. Propagule abundance did not influence recovery, as the density of coral recruits (spat <6 months old) did not differ between depths. However, mortality of juvenile corals (≤5 cm diameter) was higher at 17 m, leading to densities of juvenile corals 3.5 times higher at 10 m than at 17 m depth. Yet, there were no differences in the growth of corals between depths. These results point to an early life stage bottleneck after settlement, resulting in greater mortality at 17 m than at 10 m as the likely driver of differential coral recovery between depths. We used experiments and time-series data to test mechanisms that could drive different rates of juvenile coral mortality across depths, including differences in predation, competition, and the availability of suitable substratum. The results of these experiments suggested that increased coral mortality at 17 m may have been influenced by higher intensity of fish predation, and higher mortality of corals attached to unfavorable substratum. In contrast, the abundance of macroalgae, a coral competitor, did not explain differences in coral survival. Our work suggests that top-down processes and substratum quality can create bottlenecks in corals that can drive rates of coral recovery after disturbance.
了解基础物种如何从干扰中恢复是预测人类世生态系统未来的关键。珊瑚礁是动态生态系统，在受到干扰后珊瑚丰度可能会迅速下降。弄清楚为什么有些珊瑚礁能迅速从这些干扰中恢复，而有些则恢复缓慢（或根本无法恢复），有助于深入了解群落恢复力的驱动因素。2006年至2010年期间，法属波利尼西亚莫雷阿岛前礁的珊瑚礁遭受了严重干扰，珊瑚覆盖率从2005年的约46%降至2010年的不到1%。在这些干扰之后，2010年至2018年期间珊瑚覆盖率有所增加。尽管珊瑚迅速且广泛地恢复了，但17米深处的珊瑚礁比10米深处的恢复得更慢。我们结合珊瑚补充、密度、生长和死亡率的时间序列数据，以及测试捕食影响的野外实验，研究了2010年至2018年不同深度珊瑚恢复速率差异的驱动因素。繁殖体丰度并未影响恢复，因为不同深度的珊瑚幼体（6个月龄以下的幼体）密度没有差异。然而，17米深处幼珊瑚（直径≤5厘米）的死亡率更高，导致10米深处的幼珊瑚密度比17米深处高3.5倍。不过，不同深度的珊瑚生长没有差异。这些结果表明，定居后的早期生命阶段存在瓶颈，导致17米深处的死亡率高于10米深处，这可能是不同深度珊瑚恢复差异的驱动因素。我们利用实验和时间序列数据来测试可能导致不同深度幼珊瑚死亡率不同的机制，包括捕食、竞争和合适基质可用性的差异。这些实验结果表明，17米深处珊瑚死亡率增加可能受到鱼类捕食强度较高以及附着在不利基质上的珊瑚死亡率较高的影响。相比之下，珊瑚竞争者大型藻类的丰度并不能解释珊瑚生存的差异。我们的研究表明，自上而下的过程和基质质量会在珊瑚中造成瓶颈，从而推动干扰后珊瑚的恢复速率。
