1Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany.
2Graduate School of Simulation Studies, University of Hyogo, 7-1-28 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 Japan.
Commun Biol. 2019 Jan 28;2:40. doi: 10.1038/s42003-019-0287-8. eCollection 2019.
Food-chain length (FCL) is a fundamental ecosystem attribute, integrating information on both food web composition and ecosystem processes. It remains untested whether FCL also reflects the history of community assembly known to affect community composition and ecosystem functioning. Here, we performed microcosm experiments with a copepod (top predator), two ciliate species (intermediate consumers), and bacteria (producers), and modified the sequence of species introduction into the microcosm at four productivity levels to jointly test the effects of historical contingency and productivity on FCL. FCL increased when the top predator was introduced last; thus, the trophic position of the copepod reflected assembly history. A shorter FCL occurred at the highest productivity level, probably because the predator switched to feeding at the lower trophic levels because of the abundant basal resource. Thus, we present empirical evidence that FCL was determined by historical contingency, likely caused by priority effects, and by productivity.
食物链长度（FCL）是一个基本的生态系统属性，综合了食物网组成和生态系统过程的信息。目前还不清楚 FCL 是否也反映了已知会影响群落组成和生态系统功能的群落组装历史。在这里，我们进行了一个桡足类（顶级捕食者）、两种纤毛虫物种（中间消费者）和细菌（生产者）的微宇宙实验，并在四个生产力水平上修改了物种引入微宇宙的顺序，以共同测试历史偶然性和生产力对 FCL 的影响。当最后引入顶级捕食者时，FCL 增加；因此，桡足类的营养位反映了组装历史。在最高生产力水平下，FCL 较短，可能是因为由于丰富的基础资源，捕食者转而在较低的营养级进食。因此，我们提供了经验证据表明，FCL 由历史偶然性决定，可能是由优先效应和生产力引起的。
