Do local environmental factors structure the trophic niche of the splash tetra, Copella arnoldi? A test in an Amazonian stream system

Bruno Eleres Soares,Daniela Cristina Oliveira Rosa,Naraiana Loureiro Benone,Luciano Fogaça De Assis Montag

doi:10.1590/1809-4392201802681

Bruno Eleres Soares, Daniela Cristina Oliveira Rosa + Show 2 more

Open Access

https://doi.org/10.1590/1809-4392201802681

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Abstract

ABSTRACT Environmental variation affects the availability of spatial and trophic resources in Amazonian streams and may be important factors structuring the diet of fishes. We analyzed the diet composition and trophic niche breadth of the lebiasinid splash tetra, Copella arnoldi, aiming to evaluate how environmental variation in Amazonian streams affects the species’ trophic niche. Fish were captured and environmental factors were recorded in 20 streams in the Caxiuanã National Forest, in the eastern Amazon, in November 2010. We made a semi-quantitative analysis of stomach contents of 200 individuals. Copella arnoldi exhibited an omnivorous diet composed mainly of detritus and allochthonous invertebrates. Environmental variation (stream width, stream depth, canopy cover and flow) did not affect the diet composition or trophic niche breadth of the species, possibly due to the regional integrity of the forest within the boundaries of the protected area. Riparian cover probably minimizes the effect of the small-scale variations in food resources, thus leading to a locally homogeneous diet composition in the splash tetra C. arnoldi.

Highlights

The use of trophic resources by fish is greatly affected by temporal and spatial variation in food resources (Abelha et al 2001; Silva et al 2014; Peterson et al 2017)
Do local environmental factors structure the trophic niche of the splash tetra, Copella arnoldi? A test in an Amazonian stream system
In order to evaluate how small-scale variations in the physical structure of streams and in limnological conditions affect the diet of fish species, we studied the diet of the splash tetra Copella arnoldi (Regan 1912) in streams of the National Forest of Caxiuanã, in the eastern Amazon

Summary

Introduction

The use of trophic resources by fish is greatly affected by temporal and spatial variation in food resources (Abelha et al 2001; Silva et al 2014; Peterson et al 2017). Major examples are seasonal reproductive flights of winged ants and mayflies, or the fruitification of plants in marginal vegetation, which module the consumption of prey by numerous fish species (Netto-Ferreira et al 2007; Correa and Winemiller 2014; Barbosa et al 2015). Spatial variation in limnological factors and the physical structure of the stream and surrounding vegetation may affect the fitness of the consumer or the availability of prey (Pusey and Arthington 2003), affecting the diet of fishes. Do local environmental factors structure the trophic niche of the splash tetra, Copella arnoldi?

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