A wide trophic niche and high trophic plasticity are often invoked to explain the successful establishment of many aquatic invaders, but there is little information regarding the diet of most invasive fish in European waters. We combined stomach content and stable isotope analysis (SIA) of 13C and 15N to examine the trophic niche of the highly invasive topmouth gudgeon (Pseudorasbora parva) in three contrasting ponds and a reservoir in South Wales. Marked differences in diet and trophic position were found among neighboring systems only a few kilometers apart. The most diverse diet was found in ponds with the fewest number of inter-specific competitors, and resulted in topmouth gudgeon having the highest condition factor, the widest variation in δ13C and δ15N values, and the highest carbon content, typical of generalist feeders. In contrast, topmouth gudgeon that coexisted with other cyprinids, were much more likely to have an empty stomach and relied almost exclusively on plant seeds, resulting in fish having a poor condition factor and low trophic position. Comparisons with other trophic studies indicate that variation in isotope values among neighboring sites can exceed variation across continents, making it difficult to predict the diet or trophic impacts of the invasive topmouth gudgeon. Given the importance of obtaining reliable data on trophic position for risk assessment, our study shows that the use of SIA could be used to prioritize control and eradication measures that take into account trophic plasticity.

中文翻译：

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从稳定同位素分析推断的高侵入性 Topmouth Gudgeon (Pseudorasbora parva) 的营养可塑性

广泛的营养生态位和高营养可塑性经常被用来解释许多水生入侵者的成功建立，但关于欧洲水域中大多数入侵鱼类的饮食的信息很少。我们将胃内容物和 13C 和 15N 的稳定同位素分析 (SIA) 结合起来，检查南威尔士三个对比鲜明的池塘和水库中高侵入性顶嘴鱼（Pseudorasbora parva）的营养生态位。在相距仅几公里的相邻系统之间发现了饮食和营养位置的显着差异。在种间竞争者数量最少的池塘中发现了最多样化的饮食，并导致顶嘴鱼具有最高的条件因子、δ13C 和 δ15N 值的最大变化以及最高的碳含量，这是一般饲养者的典型特征。相比之下，与其他鲤科鱼类共存的 topmouth gudgeon 更有可能空腹并且几乎完全依赖植物种子，导致鱼的条件因子差和营养位置低。与其他营养研究的比较表明，相邻地点之间同位素值的变化可能超过各大洲的变化，因此很难预测侵入性顶嘴鱼的饮食或营养影响。鉴于获取有关营养位置的可靠数据进行风险评估的重要性，我们的研究表明，可以使用 SIA 来优先考虑考虑营养可塑性的控制和根除措施。导致鱼的条件因子差和营养位置低。与其他营养研究的比较表明，相邻地点之间同位素值的变化可能超过各大洲的变化，因此很难预测侵入性顶嘴鱼的饮食或营养影响。鉴于获取有关营养位置的可靠数据进行风险评估的重要性，我们的研究表明，可以使用 SIA 来优先考虑考虑营养可塑性的控制和根除措施。导致鱼的条件因子差和营养位置低。与其他营养研究的比较表明，相邻地点之间同位素值的变化可能超过各大洲的变化，因此很难预测侵入性顶嘴鱼的饮食或营养影响。鉴于获取有关营养位置的可靠数据进行风险评估的重要性，我们的研究表明，可以使用 SIA 来优先考虑考虑营养可塑性的控制和根除措施。