Interactions between benthic macroinvertebrates and fishes in a low order stream in Campos de Cima da Serra, RS, Brazil

Abstract

Benthic macroinvertebrates constitute the link between organic matter input in streams and fishes. However, the possibility of influence of predators on the invertebrates is still a controversial issue. The possibility of alteration of the benthic community by the modification in predation in a stream in the South of Brazil was studied by means of an exclusion experiment under semi-natural conditions. The exclusion showed an increase in the abundance of Plecoptera in the river where the rainbow trout was introduced, the larvae of Trichoptera also increased in abundance in the units of fish exclusion. This difference does not confirm the pressure applied by the trout on the benthic macro fauna due to differences in ichthyofauna and in the habitat of both rivers. Nevertheless, it points to the need for the development of studies concerning the trophic relations and the possible effects of this introduction in the aquatic biota.Keywords: benthic macroinvertebrates, low order streams, predation, exclusion experiment, exotic fish. Interações entre macroinvertebrados bentônicos e peixes em um rio de baixa ordem nos Campos de Cima da Serra, RS, Brasil ResumoOs macroinvertebrados bentônicos exercem a ligação entre a entrada de matéria orgânica nos rios e os peixes. Porém, a possibilidade de influência dos predadores sobre os invertebrados é uma questão ainda controversa. A possibilidade de alteração da comunidade bentônica, pela modificação na predação em um rio no sul do Brasil, foi estudada através de um experimento de exclusão em condições seminaturais. A exclusão resultou no aumento na abundância de Plecoptera no rio onde é feita a introdução de truta arco-íris; as larvas de Trichoptera também aumentaram em abundância nas unidades onde se efetuou a exclusão. Essa diferença não pode ser atribuída à presença das trutas, devido às diferenças na ictiofauna e de habitat dos dois rios. Entretanto mostra a necessidade de desenvolvimento de estudos acerca das relações tróficas e possíveis efeitos desta introdução sobre a biota aquática Palavras-chave: macroinvertebrados bentônicos, riachos de baixa ordem, predação, experimento de exclusão, peixe exótico.

Tolerance of benthic macroinvertebrates to organic enrichment in highland streams of northeastern Rio Grande do Sul, Brazil

“…However, prior to the use of these methods, it is necessary to determine tolerance values for bioindicator species, since the biogeographical conditions differ from one region to another. The present analysis of the taxa's extent of ocurrence in different environmental conditions, defined by conductivity and CI, contributes to increase 2005;Buckup et al, 2007;Monteiro et al, 2008;König et al, 2008;Winckler-Sosinski et al, 2008;Milesi et al, 2009;Hepp et al, 2010;Junqueira et al, 2010). Plecoptera, Trichoptera and Ephemeroptera are considered sensitive to environmental disturbances and anthropic influence (Bispo et al, 2006).…”

“…Knowledge about macroinvertebrates biodiversity in highland streams from the northeast Rio Grande do Sul is still scarce (Bueno et al, 2003;Campello et al, 2005;Buckup et al, 2007;Winckler-Sosinski et al, 2008), especially in relation to their tolerance to organic pollution, and demands detailed studies on the communities composition related to regional ecological characteristics. Surveys conducted by the authors since 2002, stored in a database, give information about biodiversity and water quality of running waters in the area.…”

Impacto del uso del suelo agropecuario sobre macroinvertebrados acuáticos en pequeñas quebradas de la cuenca del río La Vieja (Valle del Cauca, Colombia)

“…En cuanto a macroinvertebrados, los tres órdenes de insectos (Diptera, Trichoptera, Coleoptera) mejor representados en el conjunto de quebradas evaluadas se han reportado como los grupos más abundantes en quebradas de bajo orden en otros estudios (Posada, Roldán & Ramírez, 2000;Quinn, Boothroyd & Smith, 2004;Winckler-Sosinski, Silveira, Schulz & Schwarzbold, 2008). Las quebradas en zonas agrícolas y ganaderas presentaron la mayor abundancia y la mayor riqueza de familias.…”

Modelling species distributions to predict areas at risk of invasion by the exotic aquatic New Zealand mudsnail Potamopyrgus antipodarum (Gray 1843)

“…Another mollusc, the golden mussel Limnoperna fortunei (Dunker, 1857), was introduced in the Paraná River 15 years ago and, due to its high biomass production, has become an important food resource for mammals, birds, and fish; therefore, the species has had a rather limited impact on the local fauna (Sylvester, Boltovskoy, & Cataldo, 2007). Human transport of this trout is considered to be a dispersal mechanism for the snail; economic activities related to fish farming should be monitored, especially since some programmes encourage release of the trout in parts of the continent (Lazzarotto & Caramaschi, 2009;MacCrimmon, 1971;Winckler-Sosinski, Silveira, Schulz, & Schwarzbold, 2008). Human transport of this trout is considered to be a dispersal mechanism for the snail; economic activities related to fish farming should be monitored, especially since some programmes encourage release of the trout in parts of the continent (Lazzarotto & Caramaschi, 2009;MacCrimmon, 1971;Winckler-Sosinski, Silveira, Schulz, & Schwarzbold, 2008).…”

“…The hydroclimatic model showed higher accuracy and higher val- America (Buenaño, 2010;Coradin & Tortato, 2006;Lasso, Machado-Allison, & Taphorn, 2016;Oporto & Latini, 2005) and occurs in some protected areas. Human transport of this trout is considered to be a dispersal mechanism for the snail; economic activities related to fish farming should be monitored, especially since some programmes encourage release of the trout in parts of the continent (Lazzarotto & Caramaschi, 2009;MacCrimmon, 1971;Winckler-Sosinski, Silveira, Schulz, & Schwarzbold, 2008). In Colombia, the rainbow trout has been established since 1926 (MacCrimmon, 1971), and has been recorded in the Cauca and Magdalena river basins, which together cover about 25% of the country and provide 11% of the water supply for its population (Cruz-Casallas, Medina-Robles, & Velasco-Santamaría, 2011).…”