McMahon Kelton W, Thorrold Simon R, Langan Joseph A, Pi Joshua, Berumen Michael L
Graduate School of Oceanography, University of Rhode Island, 215 South Ferry Rd., Narragansett, RI 02882, USA.
Biology Department, Woods Hole Oceanographic Institution, 360 Woods Hole Rd., Woods Hole, MA 02543, USA.
Curr Biol. 2025 Jul 21;35(14):3451-3460.e4. doi: 10.1016/j.cub.2025.06.034. Epub 2025 Jul 9.
Ecologists have long sought mechanisms to explain the productivity and diversity of coral reef communities while simultaneously seeking to predict the vulnerability and resilience of said communities to environmental change. We used compound-specific stable isotope analysis to examine how different sources of primary production support coral reef food webs. We found multiple lines of evidence for distinct end-member use among three Lutjanid snapper species that are typically considered "generalist" predators and thought to feed on multiple production sources on reefs. Instead, we found that Lutjanus kasmira foraged predominantly in a water column-based phytoplankton food web (74% of carbon contribution; 95% credible interval (Crl): 62%-85%), whereas L. ehrenbergii (58% [Crl: 42%-73%]) and L. fulviflamma (55% [Crl: 44%-67%]) partitioned resource use between benthic macroalgal and coral sources, respectively. These results indicate the existence of highly siloed carbon pathways in reef food webs across at least three trophic levels, with little mixing of primary producers among species. This siloing necessitates that the intermediary (primary and secondary) consumers in these food webs forage within the same tight energy silos, likely indicating the existence of strongly maintained microhabitats on the reefs that expose consumers within these compartments to prey items linked to different primary producers through isolated food web interactions. This work identifies important resource dimensions along which species separate, providing a compelling explanation for the remarkable diversity of coral reef fishes while simultaneously raising questions about the vulnerability of food web compartments to disturbances that threaten large-scale shifts in benthic community composition.
长期以来，生态学家一直在寻找机制来解释珊瑚礁群落的生产力和多样性，同时试图预测这些群落对环境变化的脆弱性和恢复力。我们使用化合物特异性稳定同位素分析来研究初级生产的不同来源如何支持珊瑚礁食物网。我们发现了多条证据，表明三种笛鲷科鲷鱼在利用终端成员方面存在差异，这三种鲷鱼通常被认为是“广食性”捕食者，被认为以珊瑚礁上的多种生产来源为食。相反，我们发现卡氏笛鲷主要在基于水柱的浮游植物食物网中觅食（碳贡献的74%；95%可信区间（Crl）：62%-85%），而埃氏笛鲷（58%[Crl：42%-73%]）和黄焰笛鲷（55%[Crl：44%-67%]）分别在底栖大型藻类和珊瑚来源之间分配资源利用。这些结果表明，在至少三个营养级的珊瑚礁食物网中存在高度隔离的碳途径，物种间初级生产者的混合很少。这种隔离使得这些食物网中的中间（初级和次级）消费者必须在相同紧密的能量隔离区内觅食，这可能表明珊瑚礁上存在强烈维持的微生境，使这些区域内的消费者通过孤立的食物网相互作用接触到与不同初级生产者相关的猎物。这项工作确定了物种分离的重要资源维度，为珊瑚礁鱼类的显著多样性提供了令人信服的解释，同时也引发了关于食物网各部分对威胁底栖群落组成大规模变化的干扰的脆弱性的问题。
