Data from: Climate change alters the structure of arctic marine food webs due to poleward shifts of boreal generalists

Climate-driven poleward shifts, leading to changes in species composition and relative abundances, have been recently documented in the Arctic. Among the fastest moving species are boreal generalist fish which are expected to affect arctic marine food web structure and ecosystem functioning substantially. Here, we address structural changes at the food web level induced by poleward shifts via topological network analysis of highly resolved boreal and arctic food webs of the Barents Sea. We detected considerable differences in structural properties and link configuration between the boreal and the arctic food webs, the latter being more modular and less connected. We found that a main characteristic of the boreal fish moving poleward into the arctic region of the Barents Sea is high generalism, a property that increases connectance and reduces modularity in the arctic marine food web. Our results reveal that habitats form natural boundaries for food web modules, and that generalists play an important functional role in coupling pelagic and benthic modules. We posit that these habitat couplers have the potential to promote the transfer of energy and matter between habitats, but also the spread of pertubations, thereby changing arctic marine food web structure considerably with implications for ecosystem dynamics and functioning.近年来，北极地区已被记录到受气候驱动的物种向极地迁移事件，此类迁移会导致物种组成及相对丰度发生改变。移动速度最快的物种之一为北方广食性鱼类（boreal generalist fish），预计它们将对北极海洋食物网结构与生态系统功能产生显著影响。本研究针对巴伦支海（Barents Sea）高分辨率的北方与北极食物网开展拓扑网络分析，以此探讨由向极地迁移引发的食物网层级结构变化。研究发现，北方与北极食物网在结构属性与连接配置上存在显著差异：后者具有更高的模块化程度与更低的连通性。我们发现，向巴伦支海北极区域迁移的北方鱼类的核心特征之一是高度广食性，该特性会提升北极海洋食物网的连通性并降低其模块化程度。本研究结果表明，生境是食物网模块的天然边界，而广食性物种在耦合浮游与底栖食物网模块方面发挥着重要的功能作用。我们认为，这类生境连接者既能够促进生境间的能量与物质传递，也可能加剧扰动的扩散，进而显著改变北极海洋食物网结构，对生态系统动态与功能产生重要影响。