Seasonal and habitat variations in diet of the invasive driftwood catfishTrachelyopterus galeatusin a Neotropical river basin, Brazil

Abstract

The characteristics of successful invaders often include generalist traits that enable adaptation to new environments through plastic responses, including their diet. The use of trophic resources of invasive driftwood catfish Trachelyopterus galeatus of the Upper Paraná River basin, Brazil, were studied with diet analysis and stable isotopic niche metrics based on δ15N and δ13C to test differences between a free‐from‐dam and damming population, and between wet and dry season. Stomach content analyses revealed significant differences between the populations. The diet of the riverine free‐flowing river population was macroinvertebrate dominated, with Coleoptera and Lepidoptera prominent. In the damming population, diet was largely plant based, although Coleoptera was also prominent. Trophic niche breadth comparisons revealed a larger niche in the free‐from‐dam population versus the damming population that was independent of season. In both sites had dietary differences between the wet and dry season according to stomach contents analyses, although these were less prominent according to stable isotope metrics. Therefore, the diet of this invader is relatively general and plastic, enabling their exploitation of the varying availability of food resources between free‐from‐dam and damming river sections, and between wet and dry season.

Peixes Não-Nativos Em Riachos No Brasil: Estado Da Arte, Lacunas De Conhecimento E Perspectivas

“…As análises que levam em consideração as características funcionais e biológicas (e.g., alimentares, reprodutivas, estrutura populacional), também são essenciais para compreender o processo de invasão. Ainda, avaliar os impactos a partir de isótopos estáveis de carbono e nitrogênio (ver Albrecht et al 2021, neste volume) tem sido importante para avaliar se a presença de espécies não-nativas pode alterar o nicho trófico ou alimentar de espécies nativas, o fluxo de energia e a dinâmica trófica dos ambientes aquáticos (Carvalho et al 2019b, Garcia et al 2020. Portanto, os estudos sobre impactos de espécies não-nativas e padrões de diversidade em maiores escalas espaço-temporais (e.g., homogeneização/diferenciação bióticas) também devem ser incentivados (Magalhães et al 2020a), pois fornecem informações que devem ser consideradas em medidas de manejo (Figura 4).…”