Combining β Diversity and Species Responses Reveals Seasonal Changes in Fish Community Assembly Processes in a Subtropical River

ABSTRACT β diversity and its decomposed components (replacement and richness differences) reflect the processes shaping the community composition by environmental filtering and dispersal limitation. However, β diversity does not directly capture species‐specific responses to the underlying drivers of community assembly. In this study, we investigated fish communities in the Huishui River and assessed seasonal dynamics of community assembly by integrating analyses of taxonomic and functional β diversity with species‐specific responses to environmental filtering and dispersal limitation. At the basin scale, differences in turnover and richness components exhibited stronger seasonal variation than total β diversity and responded more distinctly to variations in environmental heterogeneity and community composition. The results from the Hierarchical Modelling of Species Communities (HMSC) indicated that environmental filtering primarily influenced fish community composition in both seasons, with species exhibiting varying responses to environmental and spatial factors depending on the season. These findings suggest that seasonal hydrological variation, together with species‐specific differences in environmental responses and dispersal limitation, drives shifts in fish community assembly in this subtropical river. In addition to β diversity, species‐specific responses can offer valuable species‐level insights into community assembly, which can be applied for the conservation and management of stream fish.