Hydrobiologia

, Volume 768, Issue 1, pp 183–196

Potential drivers of seasonal shifts in fish omnivory in a subtropical stream

  • Ivan González-Bergonzoni
  • Erik Jeppesen
  • Nicolás Vidal
  • Franco Teixeira-de Mello
  • Guillermo Goyenola
  • Anahí López-Rodríguez
  • Mariana Meerhoff
Primary Research Paper

DOI: 10.1007/s10750-015-2546-0

Cite this article as:
González-Bergonzoni, I., Jeppesen, E., Vidal, N. et al. Hydrobiologia (2016) 768: 183. doi:10.1007/s10750-015-2546-0

Abstract

The trophic structure of fish assemblages often varies seasonally, following the changes in food availability and supposedly water temperature. To unveil potential drivers of trophic shifts, we studied changes in fish trophic structure at both whole-assemblage and species levels at contrasting food availability and water temperatures in a subtropical stream. We analysed the diet of the most abundant omnivorous species (Bryconamericus iheringii) monthly along the year, searching for relationships with environmental variables changing seasonally (i.e. temperature and water level) and with fish reproductive stage. We ran a single-species food choice field experiment with fixed animal and vegetal food availability in contrasting seasons to test food availability as driver of diet shifts. At the assemblage level, we found a higher consumption of vegetal during summer, reflecting the increased proportion of vegetal in the diet of omnivores, which dominated the assemblage. At the species level, the enhanced vegetal consumption was related to increases in temperature and reduction in water level. Moreover, fish selected for vegetal during summer and for animal food in winter under experimental conditions. Our findings support the role of temperature driving food web dynamics by increasing fish herbivory towards warmer scenarios, with potential strong implications for whole-assemblage trophic structure.

Keywords

Fish diet Stream seasonality Temperature effect Food availability Stream food webs Fish herbivory 

Funding information

Funder NameGrant NumberFunding Note
Agencia Nacional de Investigación e Innovación
  • ANII-FCE 2530

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Ivan González-Bergonzoni
    • 1
    • 2
    • 3
  • Erik Jeppesen
    • 1
    • 2
    • 4
  • Nicolás Vidal
    • 1
    • 2
    • 3
  • Franco Teixeira-de Mello
    • 3
  • Guillermo Goyenola
    • 3
  • Anahí López-Rodríguez
    • 3
  • Mariana Meerhoff
    • 1
    • 3
  1. 1.Department of Bioscience and Arctic Research CentreAarhus UniversitySilkeborgDenmark
  2. 2.Sino-Danish Centre for Education and Research (SDC)BeijingChina
  3. 3.Departamento de Ecología Teórica y Aplicada, CURE-Facultad de CienciasUniversidad de la RepúblicaMaldonadoUruguay
  4. 4.Greenland Climate Research Centre (GCRC)Greenland Institute of Natural ResourcesNuukGreenland

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