Environmental assessment in tropical streams by using abundance-biomass curves and W index in fish assemblages

Fábio T Mise,Erivelto Goulart,João P A Pagotto,Hugo J Message

doi:10.1590/1678-4766e2018029

Abstract

ABSTRACT We investigated the fish fauna response to different environmental conditions of urban (three) and rural (seven) streams through biomass/abundance curves and W index of environmental stress. Negative values of W indicate some level of stress, while positive values suggest environments with lower stress. Dissolved oxygen, marginal erosion (both left and right margins), mesohabitat diversity, and percentage of canopy cover were measured to characterize the 10 streams analysed around Maringá city, Southern Brazil. Fish were sampled by electrofishing, then identified and weighed. Results showed negative values of W to the urban streams and positive to the rural. Urban streams showed a tendency to have assemblages of fish with lower biomass and greater abundance (r-strategists).

Highlights

We investigated the fish fauna response to different environmental conditions of urban and rural streams through biomass/ abundance curves and W index of environmental stress
Our results showed that all urban streams were environmentally stressed, while only one rural stream (Remo) had negative W value
We reinforced the trends in other studies that used abundance-biomass curves (ABC) curves, such as Pinto et al (2006) about the need of complementarities of methods in environmental assessment

Summary

Introduction

We investigated the fish fauna response to different environmental conditions of urban (three) and rural (seven) streams through biomass/ abundance curves and W index of environmental stress. Avaliação ambiental em riachos tropicais utilizando curvas de biomassa-abundância e índice W em assembleias de peixes. A resposta da fauna de peixes a diferentes condições ambientais foi verificada em riachos urbanos (três) e rurais (sete), por meio de curvas de abundância/biomassa e o índice W de estresse ambiental. Os riachos urbanos mostraram uma tendência a ter assembléias de peixes com menor biomassa e maior abundância (r-estrategistas). Despite its ecological and socioeconomic relevance, tropical streams have been very impacted by human activities These impacts have modified physical, chemical and biotic characteristics of these aquatic ecosystems, which affect the species’ abundance and composition in these environments (Malmqvist & Rundle, 2002; Englert et al, 2015) and commonly result from both urban and rural practices. Used organism in indices of environmental quality, such as the biotic integrity index, and the EPT, respectively (Kerans & Karr, 1994; Bozzeti & Schulz, 2004)

Methods

Results

Conclusion