Changes in ecosystem functions generated by fish populations after the introduction of a non-native predator (Cichla kelben) (Perciformes: Cichlidae)

The introduction of non-native predators is a matter of great concern, but their impacts on ecosystem functions remain poorly understood. We investigated how changes in fish diversity following the invasion of Cichla kelberi affected ecosystem functions generated by fish populations. Fish assemblages were sampled in macrophyte patches in a Neotropical impoundment over a 5-year period, before and after the introduction of the predator. We assigned seven ecosystem functions (26 trait-states) to each fish species, and examined how these functions behaved after the invasion. We collected 577 fish belonging to 25 species. Species richness, fish biomass and main species declined significantly over periods. The biomass of ecosystem functions changed significantly over time, and most traitstates declined. Few trait-states were lost, but all fimctions had at least one traitstate reduced by more than 85%. A null model analysis showed that changes in functions were not driven by species identities, while species richness correlated positively with total biomass and with most functions, suggesting that the loss of taxa and biomass drove observed changes in ecosystem functions. Our study provided evidence that community disassembly associated with the invasion of C. kelberi translated to the decline of several ecosystem functions, affecting energy mobilization and transference.

Automated summary

The study investigated how changes in fish diversity following the invasion of Cichla kelberi affected ecosystem functions generated by fish populations. It was found that the biomass of ecosystem functions changed significantly over time, with most trait states declining, indicating that the invasion led to the decline of multiple ecosystem functions.