Unravelling Multiple Facets of Fish Diversity: Temporal Changes and Key Drivers in the Pearl River Basin

Abstract

Aim Growing evidence suggests that, in addition to taxonomic diversity, examining functional and phylogenetic diversity offers distinct yet complementary insights into the spatial and temporal patterns of biodiversity and their driving mechanisms. Here, using a data set comprising 40 years (comparisons of 1984–1995 vs. 2010–2024), we examined spatial and temporal patterns of taxonomic, functional and phylogenetic alpha and beta diversity in fish assemblages in the Pearl River Basin (PRB), China. Location Pearl River Basin, China. Methods We used multi‐faceted diversity, principal coordinate analysis and non‐metric multidimensional scaling to analyse the spatial and temporal changes in fish biodiversity; Mantel tests and variation partitioning analysis were used to analyse the role of environmental and spatial variables on the multi‐faceted diversity indices. Results Fish assemblages exhibited significant spatial and temporal differences. Taxonomic alpha diversity of the PRB declined, but functional and phylogenetic alpha diversity increased over the analysed time period. Taxonomic and phylogenetic beta diversity showed an increased trend, but functional beta diversity declined over time. The nestedness component towards taxonomic and phylogenetic beta diversity was higher and lower than the spatial turnover component in the analysed time periods, respectively. In addition, the nestedness component towards functional beta diversity was higher than the spatial turnover component in the historical time period, and was lower in the current time period. Environmental variables were more important than spatial variables in explaining the taxonomic diversity, and spatial variables were more important in explaining functional and phylogenetic diversity in the two analysed time periods. Main Conclusions These results highlight the importance of evaluating taxonomic, functional and phylogenetic alpha and beta diversity to better understand biodiversity patterns and their driving mechanisms. Overall, the information provided by the three types of diversity is more comprehensive and offers valuable insights for biodiversity conservation, as well as monitoring and management of the PRB or other subtropical rivers experiencing similar anthropogenic disturbances.

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