Trophic relationships in fish assemblages of Neotropical floodplain lakes: selectivity and feeding overlap mediated by food availability

Rosa Maria Dias,Angelo Antonio Agostinho,Jean Carlo Gonçalves Ortega,Luiz Carlos Gomes

doi:10.1590/1678-4766e2017035

Rosa Maria Dias, Angelo Antonio Agostinho + Show 2 more

Open Access

https://doi.org/10.1590/1678-4766e2017035

Copy DOI

Abstract

ABSTRACT. The relationships between the degree of dietary overlap and food availability, and implications for food selectivity of fish species were evaluated at floodplain lakes on the upper Paraná River floodplain, Brazil. The hypothesis tested were: i) species become less selective in lakes with high availability of food resources; and ii) species (interspecific) or individual (intraspecific) present higher food overlap in conditions of high availability of food resources. In general, with the results was observed that species become less selective when the environment provided higher availability of food resources. Interspecific overlap did not show a pattern when evaluating availability of food resources in the lakes. However, intraspecific overlap tended to be more accentuated in conditions of high availability of resource food.

Highlights

The relationships between the degree of dietary overlap and food availability, and implications for food selectivity of fish species were evaluated at floodplain lakes on the upper Paraná River floodplain, Brazil
Food availability operates at individual level (Bolnick et al, 2010; Svanbäck et al, 2011), the effects of the variability of resources can be perceived at population or community levels (e.g., Bolnick et al, 2010; Martin & Pfennig, 2010)
The objective of this study was to determine the relationship between food item selection and overlap with the availability of food resources, as measured by the total bulk of items present in the stomachs of fish in six isolated floodplain lakes in the upper Paraná River floodplain

Summary

Introduction

The relationships between the degree of dietary overlap and food availability, and implications for food selectivity of fish species were evaluated at floodplain lakes on the upper Paraná River floodplain, Brazil. In natural environments, it is difficult to determine relationships, such as competition, mainly because of the lack of information about the availability of food resources in the environment. This information may be useful in determining whether, and to what degree, two or more species and/or individuals of the same species compete for the same resource. When resource availability is low, individuals can feed on a wider array of items (Martin & Pfennig, 2010; Araújo et al, 2011) and reducing the overlap among individuals of the same

Objectives

Methods

Results

Conclusion