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

Abstract

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 trait-states declined. Few trait-states were lost, but all functions had at least one trait-state 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.

Understanding the relative roles of local environmental, geo‐climatic and spatial factors for taxonomic, functional and phylogenetic β‐diversity of stream fishes in a large basin, Northeast China

“…We used R (version 4.0.2, R Core Team, 2020) for all data analysis. Spawning SPA Reproduction of the offspring of the species, key vulnerable events (Miller et al, 2015) Habit Type HTY Living environment type of fish habitat (Leal et al, 2021) Adaptation Temperature ATE Affects fish metabolism and growth rates as well as the social behavior of fish in calm water (Bartolini et al, 2015) Trophic Level TLE Types and frequency of nutritional objects in fish diet (Costello et al, 2015) Diet DIE Feeding type, food acquisition, ecological niche occupation (Costello et al, 2015) We divide the obtained data sets into abiotic and biotic data We tested the marginal significance of each variable in the model, the overall significance of the ordination solutions, and the amount of explained variation (R 2 ). In all db-RDA analyses, the sqrt.dist correction for negative eigenvalues was employed as in previous studies (Perez Rocha et al, 2018;Wu et al, 2021).…”

Ichthyofauna of Santa Helena Relevant Ecological Interest Area (REIA), Paraná, Brazil

“…Species Kullander & Ferreira, 2006 and Astronotus crassipinnis (Heckel, 1840) were recorded around RBSH; they were the first to evidence declining species richness, as well as biomass and ecosystem functions associated with them (Leal et al 2021). However, among the Cichlids, G. Sveni was the most representative in the study area of this research and its occurrence can be associated with the aquarium trade (Ota et al 2018).…”

Estrutura Populacional de Espécies do Gênero Cichla (Osteichthyes: Cichliformes) Introduzidas em Diferentes Regiões Brasileiras – uma Revisão Bibliográfica

“…Esses resultados foram reforçados por um experimento em mesocosmo que determinou uma elevada mortalidade de presas na presença do tucunaré (Kovalenko et al, 2010). Outro estudo realizado no reservatório de Rosana conclui que a introdução de C. kelberi foi responsável pela redução da riqueza de espécies, biomassa total e biomassa das principais espécies (Leal et al, 2021).…”

“…Esses impactos negativos resultaram na desestruturação e simplificação funcional das comunidades locais, causando declínio de funções ecossistêmicas como a mobilização e a transferência de energia (Leal et al, 2021). Por outro lado, no curto a médio prazo (até 5 anos) a introdução dos tucunarés não apresentou efeitos significativos na ictiofauna deste reservatório (Ferrareze & Nogueira, 2015).…”