silvia milesi | Universidade Federal do Rio Grande do Sul (original) (raw)

Papers by silvia milesi

Research paper thumbnail of Milesi_Melo_ 2013_Conditional effects of aquatic insects of small tributaries on mainstream assemblages: position within drainage network matters

Research paper thumbnail of Distribution of aquatic insects in urban headwater streams

Aims: The objective of this study was to evaluate the effects of urban environments on the distri... more Aims: The objective of this study was to evaluate the effects of urban environments on the distribution and occurrence of aquatic Ephemeroptera, Plecoptera and Trichoptera (EPT) insects in six urban subtropical streams; Methods: Organisms were collected with a Surber sampler in 2005 and 2006, over two hydrological cycles. We analyzed abundance values, taxonomic richness, Shannon-Wiener diversity and Pielou's evenness. A principal components analysis (PCA) was performed to evaluate the environmental variability of streams. A canonical correspondence analysis (CCA) was performed to evaluate the possible effects of environmental variables; Results: The PCA ordered the streams according to their quality, and Suzana and Nadau streams had higher concentrations of nutrients. The Baetidae (Ephemeroptera) was the family with the highest number of genera (18). Perissophlebiodes Savage, 1983, and Americabaetis Kluge, 1992, were the most common genera. Anacroneuria Klapálek, 1909, was the most abundant Pleocoptera, and Smicridea McLachlan, 1871, was the dominant Trichoptera genus. In the CCA, pH, electrical conductivity and stream velocity were positively correlated with axis 1, whereas dissolved oxygen was negatively correlated with axis 1; Conclusions: Our results show that the distribution of EPT in urban streams is affected by changes in water physicochemical characteristics. However, these changes are not sufficiently severe to cause the elimination of EPT.

Research paper thumbnail of Distribution of benthic macroinvertebrates in Subtropical streams (Rio Grande do Sul, Brazil)

Aim: The aim of this study was to evaluate the spatial and seasonal distribution of the benthic m... more Aim: The aim of this study was to evaluate the spatial and seasonal distribution of the benthic macroinvertebrates community in streams in the north region of Rio Grande do Sul State; Methods: The samplings were carried out in nine streams, in annual seasons. The organisms were collected with a Surber sampler (250 µm mesh; area: 0.1 m²). Environmental variables were measured to verify influences in the benthic community using a Canonical Correspondence Analysis. To evaluate the differences among communities, density, richness, diversity and evenness an ANOVA was used. To compare benthic fauna composition a MANOVA was used; Results: The environmental variables showed significant differences among the streams; however the seasons not differ. The density of organisms was significantly different among the streams and the diversity was different among the seasons. Richness and evenness not showed spatial-seasonal differences. The canonical correspondence analysis explained 67.4% of the data total variability. The main variables that influenced the benthic community were the nutrients contents, pH, electric conductivity and substrate organic matter; Conclusions: Streams with riparian vegetation and lower contents of dissolved nutrients showed higher richness of intolerant organisms to pollution. The results suggest that the distribution of benthic macroinvertebrates in the studies region was mainly related to anthropic activities developed in the catchment.

Research paper thumbnail of Effects of agricultural and urban impacts on macroinvertebrates assemblages in streams (Rio Grande do Sul, Brazil)

This study evaluates the effects of agricultural and urban activities on the structure and compos... more This study evaluates the effects of agricultural and urban activities on the structure and composition of benthic communities of streams in the state of Rio Grande do Sul, Brazil. Benthic macroinvertebrates were collected in streams influenced by urbanization and agriculture and in streams with no anthropogenic disturbances (reference streams). Organism density was superior in urban streams when compared with streams in the other two areas. The taxonomic richness and Shannon diversity index were higher in reference streams. The benthic fauna composition was significantly different among land uses. The classification and ordination analyses corroborated the results of variance analyses demonstrating the formation of clusters corresponding to streams with similar land use. Seasonality was also found to influence the benthic community, though in a lesser degree than land use.

Research paper thumbnail of Efeito de metais sobre a comunidade de macroinvertebrados bentônicos em riachos do Sul do Brasil

Acta Scientiarum. Biological Sciences, 2008

Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinc... more Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil macroinvertebrados bentônicos em riachos do sul do Brasil macroinvertebrados bentônicos em riachos do sul do Brasil macroinvertebrados bentônicos em riachos do sul do Brasil

Research paper thumbnail of Larvas de Chironomidae associadas a folhas em decomposição de Eucalyptus globulus e Eugenia uniflora em um riacho Subtropical (Rio Grande do Sul, Brasil)

Research paper thumbnail of Biasi et al _Ocorrência e distribuição de EPT em riachos

Research paper thumbnail of BIOMONITORAMENTO DAS ÁGUAS PELO USO DE MACROINVERTEBRADOS BENTÔNICOS: OITO ANOS DE ESTUDOS EM RIACHOS DA REGIÃO DO ALTO URUGUAI (RS)

Waters biomonitoring using Benthic Macroinvertebrates: eight years of studies in streams of the A... more Waters biomonitoring using Benthic Macroinvertebrates: eight years of studies in streams of the Alto Uruguai Region (RS) BIASI, C.; KÖNIG, R. MENDES, V.; TONIN, A. M. SENSOLO, D.; SOBCZAK, J. R. S. CARDOSO, R.; MILESI, S. V. RESTELLO, R. M.; HEPP, L. U.

Research paper thumbnail of Milesi_Melo_ 2013_Conditional effects of aquatic insects of small tributaries on mainstream assemblages: position within drainage network matters

Research paper thumbnail of Distribution of aquatic insects in urban headwater streams

Aims: The objective of this study was to evaluate the effects of urban environments on the distri... more Aims: The objective of this study was to evaluate the effects of urban environments on the distribution and occurrence of aquatic Ephemeroptera, Plecoptera and Trichoptera (EPT) insects in six urban subtropical streams; Methods: Organisms were collected with a Surber sampler in 2005 and 2006, over two hydrological cycles. We analyzed abundance values, taxonomic richness, Shannon-Wiener diversity and Pielou's evenness. A principal components analysis (PCA) was performed to evaluate the environmental variability of streams. A canonical correspondence analysis (CCA) was performed to evaluate the possible effects of environmental variables; Results: The PCA ordered the streams according to their quality, and Suzana and Nadau streams had higher concentrations of nutrients. The Baetidae (Ephemeroptera) was the family with the highest number of genera (18). Perissophlebiodes Savage, 1983, and Americabaetis Kluge, 1992, were the most common genera. Anacroneuria Klapálek, 1909, was the most abundant Pleocoptera, and Smicridea McLachlan, 1871, was the dominant Trichoptera genus. In the CCA, pH, electrical conductivity and stream velocity were positively correlated with axis 1, whereas dissolved oxygen was negatively correlated with axis 1; Conclusions: Our results show that the distribution of EPT in urban streams is affected by changes in water physicochemical characteristics. However, these changes are not sufficiently severe to cause the elimination of EPT.

Research paper thumbnail of Distribution of benthic macroinvertebrates in Subtropical streams (Rio Grande do Sul, Brazil)

Aim: The aim of this study was to evaluate the spatial and seasonal distribution of the benthic m... more Aim: The aim of this study was to evaluate the spatial and seasonal distribution of the benthic macroinvertebrates community in streams in the north region of Rio Grande do Sul State; Methods: The samplings were carried out in nine streams, in annual seasons. The organisms were collected with a Surber sampler (250 µm mesh; area: 0.1 m²). Environmental variables were measured to verify influences in the benthic community using a Canonical Correspondence Analysis. To evaluate the differences among communities, density, richness, diversity and evenness an ANOVA was used. To compare benthic fauna composition a MANOVA was used; Results: The environmental variables showed significant differences among the streams; however the seasons not differ. The density of organisms was significantly different among the streams and the diversity was different among the seasons. Richness and evenness not showed spatial-seasonal differences. The canonical correspondence analysis explained 67.4% of the data total variability. The main variables that influenced the benthic community were the nutrients contents, pH, electric conductivity and substrate organic matter; Conclusions: Streams with riparian vegetation and lower contents of dissolved nutrients showed higher richness of intolerant organisms to pollution. The results suggest that the distribution of benthic macroinvertebrates in the studies region was mainly related to anthropic activities developed in the catchment.

Research paper thumbnail of Effects of agricultural and urban impacts on macroinvertebrates assemblages in streams (Rio Grande do Sul, Brazil)

This study evaluates the effects of agricultural and urban activities on the structure and compos... more This study evaluates the effects of agricultural and urban activities on the structure and composition of benthic communities of streams in the state of Rio Grande do Sul, Brazil. Benthic macroinvertebrates were collected in streams influenced by urbanization and agriculture and in streams with no anthropogenic disturbances (reference streams). Organism density was superior in urban streams when compared with streams in the other two areas. The taxonomic richness and Shannon diversity index were higher in reference streams. The benthic fauna composition was significantly different among land uses. The classification and ordination analyses corroborated the results of variance analyses demonstrating the formation of clusters corresponding to streams with similar land use. Seasonality was also found to influence the benthic community, though in a lesser degree than land use.

Research paper thumbnail of Efeito de metais sobre a comunidade de macroinvertebrados bentônicos em riachos do Sul do Brasil

Acta Scientiarum. Biological Sciences, 2008

Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinc... more Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de Efeito de metais Cobre (Cu) e Zinco (Zn) sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil macroinvertebrados bentônicos em riachos do sul do Brasil macroinvertebrados bentônicos em riachos do sul do Brasil macroinvertebrados bentônicos em riachos do sul do Brasil

Research paper thumbnail of Larvas de Chironomidae associadas a folhas em decomposição de Eucalyptus globulus e Eugenia uniflora em um riacho Subtropical (Rio Grande do Sul, Brasil)

Research paper thumbnail of Biasi et al _Ocorrência e distribuição de EPT em riachos

Research paper thumbnail of BIOMONITORAMENTO DAS ÁGUAS PELO USO DE MACROINVERTEBRADOS BENTÔNICOS: OITO ANOS DE ESTUDOS EM RIACHOS DA REGIÃO DO ALTO URUGUAI (RS)

Waters biomonitoring using Benthic Macroinvertebrates: eight years of studies in streams of the A... more Waters biomonitoring using Benthic Macroinvertebrates: eight years of studies in streams of the Alto Uruguai Region (RS) BIASI, C.; KÖNIG, R. MENDES, V.; TONIN, A. M. SENSOLO, D.; SOBCZAK, J. R. S. CARDOSO, R.; MILESI, S. V. RESTELLO, R. M.; HEPP, L. U.