Do changes in the water regime determine the abundance of the copepod trophic group in a Neotropical floodplain?

Lenin Medeiros De Almeida Lino,Vanessa G Tibúrcio,Tatiane Mantovano,Fábio Amodêo Lansac-Tôha

doi:10.1590/s2179-975x4220

Lenin Medeiros De Almeida Lino, Vanessa G Tibúrcio + Show 2 more

Open Access

https://doi.org/10.1590/s2179-975x4220

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Abstract

Abstract Aim Our study evaluated the effects of extreme weather events and environmental conditions on the trophic groups of copepods (herbivores and omnivores) in the upper Paraná River floodplain. Methods The zooplankton were collected and Copepods and Rotifers were analyzed in nine environments of the upper Paraná River floodplain during 2000 and 2010, during which time the La Niña (drought) and El Niño (flood) climatic events occurred, respectively. Results The results suggest that in periods of extreme drought productivity-related variables act as determining forces on abundance of copepod trophic groups due to the contraction of aquatic ecosystems. Although the abundance of trophic groups is associated with system productivity, the responses between them differ, since herbivore abundance was associated with chlorophyll-a and total phosphorus and omnivores with rotifer abundance. In extreme flood (El Niño), no significant relationship was found between environmental variables and any trophic group. Conclusions In general, it is believed that in periods of extreme drought the variables associated with productivity act as determining forces on the abundance of trophic groups of copepods due to the contraction of aquatic ecosystems. According to the results found, it is suggested that other works be carried out with a greater number of extreme events to corroborate our results and, and also to extrapolate to other aquatic communities.

Highlights

Floodplains are ecosystems formed by distinct aquatic, terrestrial and transitional environments that have peculiar physical, chemical and biological characteristics (Junk et al, 1989; Agostinho et al, 2004; Tundisi & Matsumura-Tundisi, 2008)
Aim: Our study evaluated the effects of extreme weather events and environmental conditions on the trophic groups of copepods in the upper Paraná River floodplain
The results suggest that in periods of extreme drought productivity-related variables act as determining forces on abundance of copepod trophic groups due to the contraction of aquatic ecosystems

Summary

Introduction

Floodplains are ecosystems formed by distinct aquatic, terrestrial and transitional environments that have peculiar physical, chemical and biological characteristics (Junk et al, 1989; Agostinho et al, 2004; Tundisi & Matsumura-Tundisi, 2008) They are generally characterized by high species diversity due to habitat heterogeneity and their significant structural and functional complexity (Tockner et al, 2000; Ward et al, 2002). In Brazil, this phenomenon causes extreme drought in the Northeast and severe rainfall in the South during the summer (Grimm et al, 2000; Zhou & Lau, 1998; Cera & Ferraz, 2015) This event has been acting as a hydrological flow driver, promoting irregular flood pulses in floodplain systems (Ward et al, 2002; Räsänen & Kummu, 2013)

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