Temporal Changes of Fish Diversity and Driver Factors in a National Nature Reserve, China

Freshwater-fish diversity declined rapidly due to multiple anthropogenic disturbances. The loss of fish diversity often manifested itself in taxonomic homogenization over time. Knowledge of multi-faceted diversity (i.e., species, functional, and phylogenetic diversity) perspectives is important for biodiversity assessment and conservation planning. Here, we analyzed the change of the species diversity and phylogenetic diversity of fish in 2008 and 2021 as well as explored the driver factors of the biodiversity patterns in the Lushan National Nature Reserve. The results showed that the species diversity and phylogenetic diversity of fish have declined from 2008 to 2021, with five species lost over time. We found an overall homogenization trend in the fish fauna of the study area, with a 4% increase in taxonomic similarity among the rivers. Additionally, we found that community structure of fish was significantly different among the rivers, and environmental filtering was the main contributor to the phylogenetic diversity of fish in 2008 and 2021. This study provides new insight into the patterns and drivers of fish-biodiversity change in the broader Yangtze River basin and informs management efforts.