Rewiring and indirect effects underpin modularity reshuffling in a marine food web under environmental shifts
Rewiring and indirect effects underpin modularity reshuffling in a marine food web under environmental shifts
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DOI：
10.1002/ece3.5641
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发表时间：
2019-09-30
影响因子：
2.6
通讯作者：
Jordan, Ferenc
中科院分区：
文献类型：
--
作者：
D'Alelio, Domenico;Mele, Bruno Hay;Jordan, Ferenc
物种具有生理和行为的可塑性，这是它们对环境变化的反应的一部分。尽管如此，生态群落对环境变化的集体反应不能从单个物种反应的简单总和来预测，因为共存的物种深深地纠缠在相互作用的网络中，如食物网。由于这些原因，环境强迫与食物网结构之间的关系是生态学中的一个开放性问题。在这方面，群落生态学的主要问题之一是确定每个物种在塑造群落结构中所起的作用，例如通过促进食物网在模块中的细分，即由更频繁相互作用的物种组成的聚集体，这被报道为群落稳定剂。在这项研究中，我们调查了物种的角色和网络模块化之间的关系，在环境变化的高度分辨率的食物网，即“加权”的生态网络复制海洋浮游物种之间的碳流。测量网络特性和估计加权模块化，我们表明，物种有不同的作用，不同的影响模块化和介导的结构修改，如模块重新配置，环境变化引起的。具体而言，短期的环境变化会影响浮游初级生产者的丰度;这会影响其消费者的行为，并级联到营养链的整体重排。食物网的重新调整既有直接的，通过营养相互作用网络的重新布线，也有间接的，通过营养级联的重新配置。通过这种“系统行为”，即食物网作为一个整体的行为方式，由其各部分之间的相互作用定义，亚热带食物网经历了实质性的重新布线，同时保持几乎相同的全球流动到上层营养级，尽管环境发生了变化，但能量等级仍然保持不变。这种行为表明，浮游生物网络（如食物网）对剧烈的环境变化（如全球变化引起的环境变化）具有潜在的高弹性。
Species are characterized by physiological and behavioral plasticity, which is part of their response to environmental shifts. Nonetheless, the collective response of ecological communities to environmental shifts cannot be predicted from the simple sum of individual species responses, since co-existing species are deeply entangled in interaction networks, such as food webs. For these reasons, the relation between environmental forcing and the structure of food webs is an open problem in ecology. To this respect, one of the main problems in community ecology is defining the role each species plays in shaping community structure, such as by promoting the subdivision of food webs in modules-that is, aggregates composed of species that more frequently interact-which are reported as community stabilizers. In this study, we investigated the relationship between species roles and network modularity under environmental shifts in a highly resolved food web, that is, a "weighted" ecological network reproducing carbon flows among marine planktonic species. Measuring network properties and estimating weighted modularity, we show that species have distinct roles, which differentially affect modularity and mediate structural modifications, such as modules reconfiguration, induced by environmental shifts. Specifically, short-term environmental changes impact the abundance of planktonic primary producers; this affects their consumers' behavior and cascades into the overall rearrangement of trophic links. Food web re-adjustments are both direct, through the rewiring of trophic-interaction networks, and indirect, with the reconfiguration of trophic cascades. Through such "systemic behavior," that is, the way the food web acts as a whole, defined by the interactions among its parts, the planktonic food web undergoes a substantial rewiring while keeping almost the same global flow to upper trophic levels, and energetic hierarchy is maintained despite environmental shifts. This behavior suggests the potentially high resilience of plankton networks, such as food webs, to dramatic environmental changes, such as those provoked by global change.