Consumers play an integral role in mediating ecological succession—the change in community composition over time. As consumer populations are facing rapid decline in ecosystems around the world, understanding of their ecological role is becoming increasingly urgent. Increased understanding of how changes in consumer populations may influence community variability across space and turnover through time during succession is particularly important for coral reefs, which are among the most threatened ecosystems globally, and where fishes play vital roles in structuring benthic succession. Here, we examine how consumers influence coral reef succession by deploying 180 paired settlement tiles, caged (to exclude fishes larger than approximately 15 cm) and uncaged, within Palmyra Atoll, a remote marine wildlife refuge with previously documented high fish abundance, and monitored benthic community development one and three years after deployment. We found that excluding large fishes lead to lower alpha diversity and divergent community states across space (i.e.,, high beta diversity among caged tiles), suggesting that benthic fish feeding maintains local diversity but tends to homogenize community composition with dominance by crustose coralline algae. In addition, when fish were experimentally excluded, the developing benthic community exhibited a greater change in species composition over time (i.e., high temporal beta diversity), indicating that fish feeding tends to canalize community successional trajectories. Finally, the caged and uncaged tiles became more similar over time, suggesting that fish feeding plays a more important role during early succession. Our results demonstrate that the loss of large fishes, for example from overfishing, may result in benthic communities that are more variable across space and time. Increased variability could have important implications for ecosystem function and coral reef resilience in the face of escalating global stressors.

消费者在调节生态演替（群落组成随时间的变化）方面发挥着不可或缺的作用。随着全球消费者群体面临生态系统的迅速衰退，了解他们的生态作用变得越来越紧迫。进一步了解消费者群体的变化如何影响群落在演替过程中随时间变化的空间变化和周转率，对于珊瑚礁尤其重要，珊瑚礁是全球受威胁最严重的生态系统之一，鱼类在构建底栖演替过程中发挥着至关重要的作用。在这里，我们通过在巴尔米拉环礁内部署 180 对定居点瓷砖（以排除大于约 15 厘米的鱼类）和非笼养的方式来研究消费者如何影响珊瑚礁的演替，一个偏远的海洋野生动物保护区，之前有记录表明鱼类丰富度很高，并在部署一年和三年后监测海底群落的发展。我们发现，排除大型鱼类会导致整个空间的阿尔法多样性较低和群落状态发散（即笼养瓦片中的贝塔多样性较高），这表明底栖鱼类的摄食保持了局部多样性，但往往使群落组成均质化，以甲壳珊瑚藻为主。此外，当在实验中排除鱼类时，随着时间的推移，发展中的底栖群落表现出更大的物种组成变化（即较高的时间β多样性），表明鱼类摄食往往会形成群落演替轨迹。最后，随着时间的推移，有笼子和无笼子的瓷砖变得更加相似，表明鱼类摄食在早期演替过程中发挥着更重要的作用。我们的结果表明，大型鱼类的损失（例如过度捕捞）可能会导致底栖群落在空间和时间上变化更大。面对不断升级的全球压力，变异性的增加可能对生态系统功能和珊瑚礁的恢复力产生重要影响。