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Stream degradation in Amazonia is outpacing our ability to effectively monitor it for three key reasons: (1) Many changes are cumulative and occur gradually; (2) Scientists have failed to clearly link anthropogenic disturbances with ecological and economic indicators of concern to decision makers and the public; (3) There are too many potential indicators to assess in a cost-effective manner. Therefore, we sought to assess congruency at three taxonomic resolutions (species, genus and family) and between assemblages (fish species and macroinvertebrate genera) and groups of taxa (fish: Characiformes and Siluriformes; macroinvertebrates: Anisoptera, Heteroptera, Odonata, Trichoptera, Zygoptera, EPT [Ephemeroptera, Plecoptera and Trichoptera] and THZ [Trichoptera, Heteroptera and Zygoptera]). To do so, we assessed taxonomic, land-use and habitat data from 92 stream sites in the eastern Amazonian state of Pará. We found that anthropogenic disturbances of our sites influenced abundance and incidence of macroinvertebrate and fish taxa, but the two assemblages responded to slightly different stressors. Family and genera levels were suitable substitutes for similarity patterns measured at the macroinvertebrate genera and fish species levels, respectively. Odonata, Trichoptera, EPT and THZ were highly congruent with whole macroinvertebrate assemblage (genus level) variation. Characiformes was also congruent with whole fish assemblage (species level) variation. Congruence among macroinvertebrates and fish was intermediate (55% to 79%) and related to differing responses to environmental variables. Our results suggest that some groups (e.g., Odonata, Trichoptera and Characiformes) are useful surrogates of macroinvertebrate or fish assemblages to evaluate anthropogenic disturbance in Amazonian streams. [ABSTRACT FROM AUTHOR]

The increase of human activities in recent years has significantly interfered and affected aquatic ecosystems. In this present study, we investigate the effects of urbanization in the community structure of aquatic macroinvertebrates from Atlantic Forest streams. The sampling was conducted in the mountainous region of the State of Rio de Janeiro, Brazil in 10 urban and 10 preserved streams during the dry season (August–September) of 2012. The streams were characterized for its environmental integrity conditions and physico-chemical properties of water. The macroinvertebrates were sampled on rocky substrates with a kicknet. A total of 5370 individuals were collected from all streams and were distributed among Ephemeroptera, Odonata, Plecoptera, Hemiptera, Megaloptera, Coleoptera, Trichoptera, Lepidoptera, and Diptera. In urban sites, all those orders were found, except Megaloptera, while only Mollusca was not found in preserved streams. We performed a non-metric multidimensional scaling (NMDS) analysis that separated two groups distributed among sites in urban communities and another group outside this area. The dominance was significantly higher at urban sites, while the α diversity and equitability were greater in preserved sites. A canonical correspondence analysis (CCA) was also performed, indicating that most taxa associated with high values of the Habitat Integrity Index (HII) and a few genus of the order Diptera with the high values of ammonia, total nitrogen, associated to streams in urban sites. Urban and preserved streams differ by physical-chemical variables and aquatic macroinvertebrates. In urban streams, there is most dominance, while α diversity and equitability are higher in preserved streams. [ABSTRACT FROM AUTHOR]

This study describes the application of a protocol for biological assessment of water quality at first to third order streams at Serra dos Órgãos, an area covered by Atlantic Forest in Rio de Janeiro State, Brazil. Major impacts in the region are domestic effluents and deforestation. Our main objective is to establish biocriteria for the establishment of the Serra dos Órgãos Multimetric Index (SOMI) based on benthic macroinvertebrates. We used data from previous studies, sampled by experienced biologists, from 1999 through 2002. The benthic macroinvertebrate community was sampled in 12 reference sites and seven impaired sites in three river basins: Guapimirim, Macaé and Grande, all from the same bioregion. From the 22 tested metrics, 6 were included in the SOMI (% Diptera, % Coleoptera, Family Taxa, EPT Taxa, BMWP-CETEC and % Shredders). Scores (5, 3 or 1) were developed for these metrics to allow for aggregation into the index. Seven intermediately impaired sites were used for evaluating the applicability of the multimetric index. We concluded that the SOMI is a robust easy-to-apply tool for biomonitoring programs in the Serra dos Órgãos region, south-east Brazil. [ABSTRACT FROM AUTHOR]

Structure and composition of benthic macroinvertebrate assemblages were investigated in seven sampling sites with a gradient of environmental integrity and water quality conditions. Composite samples of the four most representative substrates were collected in order to characterize the riffle-pool dynamic in each sampling site. Spatial and temporal variability of macroinvertebrate assemblages were analyzed at two scales: using substrates and grouping samples for comparing sampling sites. Distribution of macroinvertebrates was influenced primarily by substrate type, but also by environmental integrity, water quality and sampling period. Species occurrence was highly dependent on substrate type. At local spatial scale, environmental degradation measured by the Riparian Channel Environmental Inventory and water chemistry were the determinants of assemblage patterns. We evaluated to which extent the substrates were influenced by environmental integrity and water chemistry, and we found that degradation influenced significantly the macroinvertebrate fauna on the four substrate types, although they were not responding to the same variables. Our results show that qualitatively communities were not influenced by seasonal changes, but abundance was stochastically dependent on rainfall. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrate assemblages, water chemistry variables and environmental degradation were investigated in an Atlantic Forest region in Brazil. Seven sites of the Guapimirim river basin were studied during three sampling periods based on the rain regime. Four substrates were collected at each site. Relationships between macroinvertebrate assemblages, water chemistry variables and environmental degradation were examined. Overall, the loss of community diversity measured by the Shannon Index along the degradation gradient was observed. Some taxa were shown to be sensitive to water pollution, while others were tolerant to moderate levels of pollutants. The Chironomidae were the only group tolerant to a high level of pollutants and degradation.