Community-level trophic characteristics and interactions between native and non-native fish: The example of the Lower Pearl River Basin of China

Community-level trophic characteristics and interactions between native and non-native fish: The example of the Lower Pearl River Basin of China

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Aquatic ecosystems can harbour more than one non-native fish species and this can represent a threat due to trophic interactions with native fishes.However, research on interactions amongst multiple co-occurring native and savingszoo.com non-native fish remains scarce.In this study, 551 organisms from 44 native fish, 11 non-native fish, 35 macroinvertebrates (of which one was non-native), together with 162 samples of basal resources were collected from six rivers of the Lower Pearl River Basin of China.Nitrogen and carbon stable isotope analysis was used to calculate community-wide trophic metrics and the degree of trophic overlap between native and non-native fish at both the community and functional feeding group level, together with diet composition.

At the community level, there was a high degree of trophic niche overlap between native and non-native fish as a result of similarities in trophic characteristics.At the functional feeding group level, both native and non-native functional feeding groups demonstrated the capacity to occupy the niche space of each other.A significant trophic rectangular barn quilt patterns niche overlap, exceeding 50%, was found between non-native detritivorous and omnivorous fish, suggesting competition.The difference in diet composition between some native and non-native fish depended on the category of diet source across the rivers, suggesting dietary segregation.

Albeit limited, the present findings suggest that trophic interaction between native and non-native fish is likely to reach a dynamic equilibrium status in the community owing to trophic segregation of fish species and the antagonistic effects amongst non-native fish.