(Table A1) Species list of the high Antarctic Weddell Sea food web

Human-induced habitat destruction, overexploitation, introduction of alien species and climate change are causing species to go extinct at unprecedented rates, from local to global scales. There are growing concerns that these kinds of disturbances alter important functions of ecosystems. Our current understanding is that key parameters of a community (e.g. its functional diversity, species composition, and presence/absence of vulnerable species) reflect an ecological network's ability to resist or rebound from change in response to pressures and disturbances, such as species loss. If the food web structure is relatively simple, we can analyse the roles of different species interactions in determining how environmental impacts translate into species loss. However, when ecosystems harbour species-rich communities, as is the case in most natural systems, then the complex network of ecological interactions makes it a far more challenging task to perceive how species' functional roles influence the consequences of species loss. One approach to deal with such complexity is to focus on the functional traits of species in order to identify their respective roles: for instance, large species seem to be more susceptible to extinction than smaller species. Here, we introduce and analyse the marine food web from the high Antarctic Weddell Sea Shelf to illustrate the role of species traits in relation to network robustness of this complex food web. Our approach was threefold: firstly, we applied a new classification system to all species, grouping them by traits other than body size; secondly, we tested the relationship between body size and food web parameters within and across these groups and finally, we calculated food web robustness. We addressed questions regarding (i) patterns of species functional/trophic roles, (ii) relationships between species functional roles and body size and (iii) the role of species body size in terms of network robustness. Our results show that when analyzing relationships between trophic structure, body size and network structure, the diversity of predatory species types needs to be considered in future studies.人为活动引发的栖息地破坏、过度开发、外来物种引入与气候变化，正以史无前例的速率在局地乃至全球尺度上造成物种灭绝。日益引发学界关注的是，此类扰动会改变生态系统的核心功能。当前学界普遍认为，群落的关键参数（如功能多样性、物种组成以及易危物种的存在与否），可反映生态网络在面对物种丧失等压力与扰动时的抗干扰能力与恢复能力。若食物网结构相对简单，我们可通过解析不同物种间的相互作用，阐明环境影响如何转化为物种丧失过程。然而多数自然生态系统均拥有物种丰富的群落，复杂的生态相互作用网络使得我们难以探明物种功能角色如何影响物种丧失的后续效应。应对此类复杂性的可行路径之一，是聚焦物种的功能性状以明确其各自的生态角色：例如，大型物种相较小型物种更易走向灭绝。本研究以南极高纬度威德尔海陆架（Weddell Sea Shelf）的海洋食物网为研究对象，通过对其展开介绍与分析，阐释物种性状与该复杂食物网鲁棒性之间的关联。本研究采用三维分析框架：其一，针对所有物种建立全新分类体系，以体型以外的功能性状进行类群划分；其二，检验该类群内部及类群间体型与食物网参数之间的关联；其三，计算食物网的鲁棒性。本研究旨在解答以下三类问题：（1）物种功能/营养角色的分布模式；（2）物种功能角色与体型之间的关联；（3）物种体型在网络鲁棒性中的作用。研究结果表明，在开展营养结构、体型与网络结构三者间的关联分析时，未来研究需纳入捕食者类群的多样性维度。