Expanding human activities alongside climate change, the introduction of invasive species and water contamination pose multiple threats to the unique marine ecosystems of the Pechora Sea in the Russian Arctic. Baseline data on biodiversity and responses to environmental change are urgently needed. Benthic decapod crustaceans are globally distributed and play an important role in fisheries, yet their roles in food webs are less understood. In this study, we used an integrated approach combining stomach content analysis and stable isotope analyses (δ13C and δ15N) to examine the trophic niches of three decapod species in the Pechora Sea including the invasive snow crab Chionoecetes opilio and two species of native decapods, the spider crab Hyas araneus and the hermit crab Pagurus pubescens. Stomach contents of 75 decapods were analysed (C. opilio n = 23; H. araneus n = 9; P. pubescens n = 43), and 20 categories of prey items were identified with the most frequently occurring prey items being bivalve molluscs (Ciliatocardium ciliatum, Ennucula tenuis, Macoma calcarea), polychaetes, crustaceans and plant debris. Bayesian ellipse analyses of stable isotope signatures (n = 40) revealed that C. opilio displays an overlapping trophic niche with the two native decapods, providing direct evidence that the invader likely competes for food resources with both H. araneus and P. pubescens. As such, the presence of this invasive species could hold important consequences for trophic interactions, benthic ecosystem functioning and biodiversity. Microplastics were also found to be a likely stressor on this ecosystem, as 28% of all stomachs contained digested microplastics among other items. Long-term studies of benthic ecosystem structure and functioning are now needed to more fully understand the extent to which this new competitor may alter the future biodiversity of the Pechora Sea alongside the additional stressor of digested plastics.

中文翻译：

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伯朝拉海底栖甲壳类动物的营养生态位表明入侵的雪蟹 Chionoecetes opilio 可能是一个重要的竞争者

随着气候变化、入侵物种的引入和水污染，人类活动不断扩大，对俄罗斯北极地区伯朝拉海独特的海洋生态系统构成了多重威胁。迫切需要关于生物多样性和对环境变化的反应的基线数据。底栖十足目甲壳类动物分布于全球，在渔业中发挥着重要作用，但它们在食物网中的作用却鲜为人知。在这项研究中，我们使用了一种结合胃内容物分析和稳定同位素分析（δ13C 和 δ15N）的综合方法来检查伯朝拉海三种十足动物的营养生态位，包括入侵的雪蟹 Chionoecetes opilio 和两种本地十足动物，蜘蛛蟹 Hyas araneus 和寄居蟹 Pagurus pubescens。分析了 75 只十足目动物的胃内容物 (C. opilio n = 23; H. araneus n = 9; P. pubescens n = 43)，并确定了 20 类猎物，其中最常见的猎物是双壳类软体动物（纤毛纤毛、Ennucula tenuis、Macoma calcarea）、多毛类、甲壳类和植物碎片。稳定同位素特征（n = 40）的贝叶斯椭圆分析显示，C. opilio 显示出与两种原生十足足动物重叠的营养生态位，提供了直接证据表明入侵者可能与 H. araneus 和 P. pubescens 争夺食物资源。因此，这种入侵物种的存在可能对营养相互作用、底栖生态系统功能和生物多样性产生重要影响。还发现微塑料可能是这个生态系统的压力源，因为所有胃中有 28% 含有消化的微塑料和其他物品。