Assessment of fish assemblages in streams of different orders in the Upper Paraná River basin, Central Brazil

Abstract

ABSTRACT. The aim of this study was to test whether the richness observed and the biomass per trophic group of fish assemblages vary depending on the order (1 st and 2 nd ) of the streams located in three different basins of the Upper Paraná River Basin, Central Brazil. Samples were collected between April and September, 2009, in 27 streams of the Meia Ponte, Piracanjuba and Santa Maria River basins. A total of 4,879 specimens were collected distributed in 59 species and 19 families. The statistical analyses carried out indicate that the observed richness and biomass of omnivore fish were influenced by the interaction of two factors: stream order and basin. The 2 nd order streams located in the Santa Maria basin presented significant differences in the observed richness and omnivore biomass when compared to i) 1 st order streams in the same basin (only richness) or in the Piracanjuba and Meia Ponte basin; ii) 2 nd order streams in the Piracanjuba (only omnivore biomass) and Meia Ponte Rivers basins. Results are discussed considering the influence of geomorphic processes on fish assemblages and food availability. KEYWORDS.Trophic guilds, omnivores, richness, biomass.RESUMO. Avaliação das assembleias de peixes de riachos de diferentes ordens na bacia do alto rio Paraná, Brasil Central. O objetivo deste estudo foi testar se a riqueza observada e a biomassa por grupo trófico das assembleias de peixes variam de acordo com a ordem (1ª e 2ª) dos riachos localizados em três bacias diferentes do sistema do alto rio Paraná, Brasil Central. As amostras foram coletadas entre abril e setembro de 2009 em 27 riachos das bacias dos rios Meia Ponte, Piracanjuba e Santa Maria. Um total de 4.879 espécimes foi coletado distribuídos em 59 espécies e 19 famílias. As análises estatísticas realizadas indicam que a riqueza observada e a biomassa de peixes onívoros foram influenciadas pela interação de dois fatores: a ordem do riacho e a bacia. Os riachos de 2ª ordem localizados na bacia do rio Santa Maria apresentaram diferenças significativas de riqueza observada e biomassa de onívoros, quando comparado: i) aos riachos de 1ª ordem da mesma bacia (somente a riqueza), da bacia do rio Piracanjuba ou do Meia Ponte; ii) aos riachos de 2ª ordem da bacia do rio Piracanjuba (somente a biomassa de omnívoros) ou do rio Meia Ponte. Os resultados obtidos são discutidos considerando a influência dos processos geomórficos sobre a assembleia de peixes e a disponibilidade de alimento.

Elements of fish metacommunity structure in Neotropical freshwater streams

“…Accordingly, each sampled stream was considered as a community and the set of streams as the metacommunity. This approach is justified by the low ichthyofaunal similarity observed between streams (1st–3rd order) and rivers (>4th order; Araújo & Tejerina‐Garro, 2007; Melo et al., 2009; Dias & Tejerina‐Garro, 2010; Vieira & Tejerina‐Garro, 2014).…”

“…Red points indicate the spatial distribution of streams sampled (communities) in the Paraná River basin, Brazil. The shaded area represents the vegetation cover (Brazilian savannah) rivers (>4th order; Araújo & Tejerina-Garro, 2007;Melo et al, 2009;Dias & Tejerina-Garro, 2010;Vieira & Tejerina-Garro, 2014). Next, a species pool for each trophic guild was constructed and analyses performed to identify patterns; only pools with more than 15 species were considered (Table S2).…”

“…Red points indicate the spatial distribution of streams sampled (communities) in the Paraná River basin, Brazil. The shaded area represents the vegetation cover (Brazilian savannah) rivers (>4th order; Araújo & Tejerina-Garro, 2007;Melo et al, 2009;Dias & Tejerina-Garro, 2010;Vieira & Tejerina-Garro, 2014).…”