Unravelling fish community assembly in shallow lakes: Insights from functional and phylogenetic diversity

Global biodiversity loss has increased interest in identifying the patterns and mechanisms that shape community assembly. Growing empirical evidence indicates that investigating functional and phylogenetic diversity beyond purely taxonomic considerations may provide different but complementary information about community assembly. However, such multifaceted studies on community assembly from both functional and phylogenetic perspectives are rare in the context of fish assemblages in lakes. We examined patterns of functional and phylogenetic alpha diversity in fishes and explored the relationships between these patterns and their environmental drivers across broad environmental gradients in 30 shallow lakes. Furthermore, we examined community assembly mechanisms using null models to quantify the relative importance of deterministic and stochastic assembly processes. Our results revealed no clear patterns among multiple biodiversity components and their environmental drivers, and no single component could be used as a reliable proxy for another; these results suggest that accounting for functional and phylogenetic diversity can help to explain fish community variation. Null models revealed that both deterministic and stochastic assembly processes occurred simultaneously, with stochastic processes being responsible for the majority of fish community assembly processes in most of our study lakes. Taken together, these results highlight the importance of evaluating both functional and phylogenetic alpha diversity when identifying patterns of community assembly.