Drastic reduction of the functional diversity of native ichthyofauna in a Neotropical lake following invasion by piscivorous fishes

Abstract

Biological invasions are leading several species to extinction and are projected as a main driver of biodiversity changes in lakes for this century. However, the knowledge of their impacts on the Neotropical ichthyofauna over time remains largely incipient, especially when considering the functional diversity of native communities. Here we aim to identify the effects of non-native species, especially the non-native piscivorous Cichla kelberi and Pygocentrus nattereri, on the functional diversity of the native ichthyofauna of the Carioca Lake, Middle Rio Doce basin, state of Minas Gerais. Using fish occurrence data for eight years from 1983 to 2010 combined with an ecomorphological-trait analysis, we found that while the native species richness dropped to 56%, the functional richness is only 27% of that found before introductions. In other words, more than species, the ichthyofauna suffered an impressive decline in the range of functional traits, which can further have severe impacts on ecological processes within that system. When considering all the components of the current ichthyofauna (native and non-native species), neither taxonomic nor functional richness have changed over time. However, even keeping biodiversity levels, non-native species are not able to fully compensate for the extinct native ones in terms of functions.

Interactions between Bacterial Inoculants and Native Soil Bacterial Community: the Case of Spore-formingBacillusspp.

“…Since BM could better compete for some resources than the resident community, we speculate that resident taxa using the same carbon sources as the invader might have been outcompeted, leading to the decline of these taxa's abundance, thereby reducing these taxa's abundance in the niche breadth of resident bacterial communities. Such a decline in diversity following invasion has been observed in micro- (Mawarda et al 2020 ) and macroorganisms (Carboni et al 2021 , Sapsford et al 2022 ), which often leads to the changes in their functional diversity (Mallon et al 2018 , Matsuzaki et al 2016 , Souza et al 2021 , Xing et al 2020 ). This type of footprint of microbial invaders on soil communities has to be accounted for to fully appreciate the impact of invasion on soil functioning and services (Liu et al 2022 ).…”

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

“…Latini & Petrere (2004) determinaram que a presença de espécies exóticas invasoras, incluindo C. monoculus, foi significativamente correlacionada com a redução da riqueza de espécies locais nos sistemas lacustres do Parque Estadual do Rio Doce, em Minas Gerais. Outro estudo recente realizado em um lago situado na bacia do rio Doce, que avaliou dados de ocorrência de 1983 a 2010, determinou que a riqueza de espécies e, principalmente a riqueza funcional, foram significativamente afetadas pela introdução das espécies exóticas C. kelberi e Pygocentrus nattereri (Souza et al, 2021).…”

Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

“…The introduction of exotic fish species, for example, can bring a series of diseases and parasites for which native species do not have defenses, and may even affect commercial crops (Latini et al, 2016). In the Rio Doce basin, Souza et al (2021) demonstrate that the invasion of several predatory fish, especially the two introduced piscivores tucunaré Cichla kelberi and piranha Pygocentrus nattereri, eroded the taxonomic and functional diversity of Neotropical freshwater fishes in natural lakes, including the extirpation of at least seven species.…”