Fish assemblages in stream stretches occupied by cattail (Typhaceae, Angiospermae) stands in Southeast Brazil

Abstract

Macrophytes are a major component of lentic and lotic aquatic ecosystems. As consequences of environmental degradation, species of cattail (genus Typha) may become dominant along streams. The purpose of this study was to investigate the structure and feeding of fish assemblages in stream stretches under influence of Typha sp., also addressing the influences of temporal variation on composition, abundance, biomass, diversity, species richness, and feeding of fish. Six streams (labelled S1-S6) in the upper rio Turvo basin, southeast Brazil, with dense stands of Typha sp. in the instream and riparian habitat, were studied in six campaigns during three central months in both of the dry and wet periods, by using a standardized collection effort. Thirty-seven fish species were registered, totaling 4,228 individuals and 3.9 kg of biomass. Abundance, biomass, diversity, and species richness was higher in the wet period, but only the temporal variation in the species richness revealed to be statistically significant. Cluster analyses with composition and abundance showed little temporal similarity, but indicated two groups of streams (S1-S2-S5 and S3-S4-S6), that were corroborated along the axis 1 of the ordination analysis. Resident species was represented by six species, most of them considered tolerant and generalists. Chironomidae aquatic larvae and detritus were the most important items in the fish diet. These results suggest that the fish populations are opportunistic in exploring stream stretches occupied by cattail.Macrófitas são um importante componente de ecossistemas aquáticos lóticos e lênticos. Como consequências da degradação ambiental, espécies de taboas (gênero Typha) podem se tornar dominantes em riachos. O objetivo do presente estudo foi investigar a estrutura e alimentação de uma comunidade de peixes em trechos de riachos com influência de Typha sp., bem como a variação temporal na composição, abundância, biomassa, diversidade, riqueza de espécies e alimentação da ictiofauna. Seis riachos (nomeados S1-S6) na bacia do alto rio Turvo, sudeste do Brasil, com densos bancos de Typha sp. no habitat interno e ripário, foram estudados em seis campanhas durante os três meses centrais dos períodos seco e chuvoso, por meio de um esforço padronizado de coleta. Trinta e sete espécies foram registradas, totalizando 4.228 indivíduos e 3,9 kg de biomassa. Abundância, biomassa, diversidade e riqueza de espécies foram maiores no período chuvoso, mas somente as diferenças temporais na riqueza de espécies se mostraram estatisticamente significativas. As análises de agrupamentos com a composição e abundância mostraram baixa similaridade temporal, mas indicaram dois grupos de riachos (S1-S2-S5 e S3-S4-S6), o que foi corroborado ao longo do eixo 1 da análise de ordenação. A fauna de peixes residente foi representada por seis espécies, a maioria tolerante e com hábitos generalistas. Larvas aquáticas de Chironomidae e detritos foram os itens mais importantes na dieta dos peixes. Os resultados obtidos sugerem que as populações ...

From forests to cattail: how does the riparian zone influence stream fish?

“…1 Andrian et al (1994), Castro & Casatti (1997), Uieda et al (1997), Gibran et al (2001), Casatti (2002), Ferreira & Casatti (2006) and Rocha et al (2009).…”

“…1c), there are favorable conditions to the establishment of rooted macrophytes, especially cattails of the genus Typha. In this situation, ichthyofauna is dominated by accidental and opportunists species capable of consuming organic detritus which became the dominant food item under such circumstances (Rocha et al, 2009).…”

Influence of the riparian zone phytophysiognomies on the longitudinal distribution of fishes: evidence from a Brazilian savanna stream

“…were captured exclusively in upstream reaches (Table 3) and always associated with shoreline vegetation in contact with the water. This is probably associated with preferential use of submerged vegetation by Gymnotiformes species for diurnal shelter and feeding (Ferreira & Casatti, 2006;Ferreira, 2007;Rocha et al, 2009). Two other species, Farlowella paraguayensis and Hemiloricaria lanceolata, also occurred associated with marginal areas with dense vegetation and were important for the dissimilarity between upstream and downstream reaches according to the similarity percentage analysis.…”

“…In upstream reaches, the small size of the abundantly present shoreline vegetation on the low banks favors their contact with the stream water. Foliage leaning over the channel and roots extending internally increase the spatial heterogeneity of in-stream habitats, creating specific microhabitats (Collier et al, 1999;Rocha et al, 2009) usually explored by species with specialized needs. In fact, some species such as Apteronotus albifrons, Brachyhypopomus sp., Eigenmannia trilineata and Gymnotus sp.…”

Cost of territorial maintenance by Parodon nasus (Osteichthyes: Parodontidae) in a Neotropical stream

“…The pelvic and pectoral fins of individuals in this family are well developed and adapted to stabilize the fish in the fast water and rocky bottom of rivers and streams where they are usually found grazing on algae (Sazima, 1980). Recently, Gomiero & Braga (2008) classified this species as insectivorous-iliophagous in the Corumbataí River, where P. nasus is abundant in a very polluted area with high deposition of organic matter, and Rocha et al (2009) working with specimens from a stream stretches occupied by dense stands of aquatic macrophytes has classified it as invertivore.…”