Abstract

It is critical to understand the potential effects of non-native species, especially on ecologically similar native species, and to reveal their trophic relationships. Cyprinid invasive fishes, Carassius gibelio, and translocated fish Cyprinus carpio has been introduced to the Karacaören I reservoir located in the upstream reach of the Aksu River basin. Karacaören reservoir is also an important local habitat for native Cyprinid fishes, Capoeta antalyensis and Squalius fellowesii. In this study, we evaluated the trophic structure and interspecies trophic interactions (as isotopic niches and niche overlaps) of these Cyprinid fish using stable C and N isotopes analysis as measured by Isotope Ratio Mass Spectrometer. While equally all food sources contributed to the biomass of all fish species in the summer, their biomass is supported by more specialized sources in the winter season. Our results revealed increased niche breadth with increased niche overlap between C. antalyensis and C. gibelio, and C. carpio, and among C. gibelio and C. carpio in the summer, while decreased niche breadth with decreased niche overlap in the winter season. Interspecific competition has led to trophic niche divergence, which may facilitate the coexistence of native species with introduced fishes. Non-native fish were determined to have larger niche widths, which may contribute to their invasion success.

摘要

了解非本地物种的潜在影响，尤其是对生态相似的本地物种的潜在影响，并揭示它们的营养关系至关重要。鲤科入侵鱼类、银鳕鱼和易位鱼类鲤鱼已被引入位于阿克苏河流域上游的 Karacaören I 水库。Karacaören 水库也是本地鲤科鱼类、Capoeta antalyensis和Squalius fellowesii的重要当地栖息地. 在这项研究中，我们使用同位素比质谱仪测量的稳定 C 和 N 同位素分析评估了这些鲤鱼的营养结构和种间营养相互作用（如同位素生态位和生态位重叠）。同样，所有食物来源都在夏季为所有鱼类的生物量做出了贡献，而在冬季，它们的生物量则得到了更专业的来源的支持。我们的结果表明，随着C. antalyensis和C. gibelio、C. carpio之间以及C. gibelio和C. carpio之间的生态位重叠增加，生态位宽度增加在夏季，生态位宽度减少，冬季生态位重叠减少。种间竞争导致营养生态位分化，这可能促进本地物种与引进鱼类的共存。非本地鱼类被确定具有更大的生态位宽度，这可能有助于它们的入侵成功。