CONCLUSION
Our study reveals the manner in which patterns and extent of fish
homogenization and differentiation induced by low-head dams in
subtropical streams in China. In this study, we found that taxonomic
differentiation accompanied functional homogenization in stream fish
assemblages because of the decrease in abundance of shared native
species with unique functional traits. More importantly, these results
showed the importance of population abundance in structuring fish faunal
homogenization and differentiation at small scales, especially when the
major differences among assemblages are in species abundance ranks
rather than species identities. Additionally, our study proved that
changes in taxonomic similarity cannot be used to predict changes in
functional similarity. Considering the dynamic processes of biotic
homogenization and differentiation, fish assemblages could exhibit
homogenization in the future as native-invasive species continue to
spread and native species become extirpated. Therefore, future studies
should continue monitoring to protect existing biodiversity that aimed
at mitigating the ecological effects of low-head dams.