Biomonitoring is defined as the systematic use of biological responses to assess environmental changes, usually anthropogenic impacts. In this article we present the conceptual basis and a brief history of biomonitoring as an assessment tool for environmental health. Considering the drawbacks of physical and chemical parameters to assess environmental quality, we pinpoint the need to integrate these analyses with information provided by biological monitoring. The application of biomonitoring in Brazil would help watershed managers and policy-makers to reduce costs, increase the efficiency of analyses, and simplify the results, allowing community participation through volunteer monitoring programs.

Diversity and habitat preference of macroinvertebrates were studied in Macaé River basin, Rio de Janeiro State, Brazil, along its longitudinal gradient. We selected stream reaches corresponding to 1 st , 2 nd , 4 th , 5 th and 6 th orders. A Surber sampler was used to collect four macroinvertebrates samples of each substrate (sand, litter in pool areas, stones, and litter in riffle areas) during the three sampling periods, defined based on the rain regime: April (end of the rainy season), July (dry season), and October (beginning of the rainy season). We identified 46,431 specimens corresponding to 117 taxa. Analysis of diversity numbers (both for family or genus level) indicated that all insect taxonomic orders had higher numbers on 2 nd order stream reach, except for Ephemeroptera, on 4 th order. However when considering morphspecies taxonomic level, the higher diversity number occurred on 4 th order stream. The highest richness and diversity numbers were found at the dry season. Considering habitat preference, both litter in pool areas and litter in riffle areas had the highest faunal richness.Key words: diversity, aquatic insects, longitudinal gradient, tropical river, Brazil. RESUMO

Benthic macroinvertebrate assemblages are structured according to physical and chemical parameters that define microhabitats, including food supply, shelter to escape predators, and other biological parameters that influence reproductive success. the aim of this study is to investigate spatial and temporal distribution of macroinvertebrate assemblages at the macaé river basin, in rio de Janeiro state, Southeastern Brazil. according to the "habitat assessment field data Sheet -high Gradient Streams" (Barbour et al., 1999), the five sampling sites are considered as a reference condition. despite the differences in hydrological parameters (mean width, depth and discharge) among sites, the physicochemical parameters and functional feeding groups´ general structure were similar, except for the less impacted area, which showed more shredders. according to the detrended correspondence analysis based on substrates, there is a clear distinction between pool and riffle assemblages. in fact, the riffle litter substrate had higher taxa in terms of richness and abundance, but the pool litter substrate had the greatest number of exclusive taxa. a cluster analysis based on sampling sites data showed that temporal variation was the main factor in structuring macroinvertebrate assemblages in the studied habitats.Keywords: benthic macroinvertebrates, Southeastern Brazil, substrates, distribution. RESUMODistribuição espaço-temporal de macroinvertebrados bentônicos em um rio do sudeste brasileiro a fauna de macroinvertebrados bentônicos é estruturada por fatores físicos e químicos que determinam os microhábitats, incluindo a disponibilidade de alimento, a existência de refúgios contra predadores e tempestades, o sucesso reprodutivo e outros parâmetros biológicos. o objetivo deste estudo foi investigar a distribuição espaço-temporal da comunidade de macroinvertebrados bentônicos na bacia do rio macaé, estado do rio de Janeiro, Brasil. de acordo com o Habitat Assessment Field Data Sheet -High Gradient Streams (Barbour et al., 1999), os cinco locais coletados são considerados como referência para propósito de biomonitoramento. apesar das diferenças em parâmetros hidrográficos (largura, profundidade e vazão médias), os parâmetros físico-químicos e a composição dos grupos de alimentação funcional foram similares entre os locais, com exceção da área mais preservada, onde a porcentagem de organismos cortadores foi maior. de acordo com a análise de correspondência, há uma clara distinção entre áreas de remanso e de correnteza. de fato, o substrato folhiço de correnteza apresentou a fauna mais rica e abundante, enquanto o substrato folhiço de fundo apresentou o maior número de táxons exclusivos. a análise de agrupamento 624 Silveira, m. p. et al.

ABSTRACT. Composition and microhabitat preferences of Odonata (Insecta) immatures in a lowland section of the Rio Ubatiba, Maricá-RJ, Brazil. Monthly sampling was held from May, 1999 to May, 2000 in the Rio Ubatiba, a lowland river situated at Maricá district, Rio de Janeiro State, Brazil. Seven different substrates were collected along fifty meters. A total of 1,279 larvae of Odonata were collected and identified in 27 species, belonging to five families. The most numerous species were Acanthagrion lancea (Selys, 1876), Hetaerina auripennis (Burmeister, 1839), Micrathyria hesperis Ris, 1911 and Telebasis filiola (Perty, 1834). The greatest number of individuals were found in "riparian plants in depositional areas". In general, the species recorded showed habitat preferences: Dythemis multipunctata Kirby, 1894, Erythrodiplax sp., M. hesperis, T. filiola, A. lancea, Erythemis sp., Coryphaeschna adnexa (Hagen, 1861) and H. auripennis seem to prefer organic substrates and Brechmorhoga sp., B. praecox (Hagen, 1969) and Progomphus complicatus Selys, 1854, inorganic substrates.

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In the current study we add new records of 29 species of Caddisflies (Trichoptera) from eight different Brazilian states and report Leptonema sancticaroli Flint, McAlpine and Ross, 1987, Flintiella pizotensis Harris, Flint and Holzenthal, 2002, and Oecetis connata Flint, 1974 for the first time in Brazil.

Aim: The aim of this paper was to study the spatial distribution and functional feeding structure of aquatic insect communities of 18 streams at different altitudes in Mambucaba River Basin, Serra da Bocaina, Southeastern Brazil; Methods: Samples were collected in two consecutive dry periods (August of 2003 and being sampled four substrate types in each stream: litter from riffles, litter from pools, rocks and gravel; Results: We identified 75,581 aquatic insect individuals belonging to 201 taxa. Most of the fauna was found in litter substrates (64%), and riffle litter substrate had the majority of the specimens (32,572 individuals). Gravel was the substrate with highest values of richness (29.84 taxa expected for 187 individuals; rarefaction method) and Shannon's diversity (H' = 2.370). Rock substrate showed the lowest richness (20.24 taxa). Distribution of taxa across substrates shows that only 28 taxa are restricted to a single substrate, while 78 taxa occurred in all substrates. The indicator analysis showed that 20 taxa were characteristic of pool litter, 25 of riffle litter, 22 of gravel and only nine to rock. In relation to organic and inorganic substrates, 29 taxa were characteristic of litter, and 17 of inorganic substrates. Cluster analysis based on Bray-Curtis dissimilarity index and UPGMA linkage method showed that aquatic insects were distributed according to substrate and food resource. In all substrates, the main functional feeding group was collector-gatherer (40.64%), and the least representative was shredder (6.67%). ANOVA and Tukey HSD tests showed that collector-gatherers and shredders were predominant in pool substrates, collector-filters in riffle substrate and scrapers in hard substrates; Conclusion: Ours results show that independently of stream or altitude, substrate of the same type have similar faunal assemblages. The abundance and relative proportion of the functional feeding group showed variation across habitats.Keywords: distribution, habitats, substrates, benthic macroinvertebrates.Resumo: Objetivo: O objetivo deste artigo foi estudar a distribuição espacial e a categorização funcional trófica da comunidade de insetos aquáticos de 18 riachos em diferentes altitudes na Bacia do Rio Mambucaba, Serra da Bocaina, Sudeste do Brasil; Métodos: As amostras foram coletadas em dois períodos secos consecutivos (agosto de 2003 e 2004), sendo coletados em quatro tipos de substratos: folhiço em correnteza, folhiço de fundo, pedras e cascalho; Resultados: Foram identificados 75.581 indivíduos de insetos aquáticos pertencentes a 201 táxons. Os substratos com folhiço concentraram a maior parte da fauna (64%), sendo o folhiço em correnteza o substrato com maior abundância de indivíduos (32.572). O cascalho apresentou os maiores valores de riqueza (29,84 táxons esperado em 187 indivíduos; método da rarefação) e diversidade de Shannon (H' = 2,370). A menor riqueza (20,24 táxons) foi observada no substrato pedra. A distribuição dos táxons entre os substratos mostrou 28 táxons restritos a um...

Aquatic macroinvertebrate diversity and composition in streams along an altitudinal gradient in Southeastern Brazil. A study concerning taxonomic richness and composition of the aquatic insect fauna in streams within the same catchment basin along an altitudinal gradient in Southeast Brazil, was conducted to test the hypothesis that there is a faunal discontinuity in the biocenotic composition, related to differences in altitude and latitude. In Southeastern Brazil, around latitude 22°, this faunal transition from rhithron to potamon biocenosis should occur at 500 m above sea level. Eighteen tributaries of the Mambucaba River, at Serra da Bocaina National Park, SP-RJ, Brazil, were studied. The streams were separated into 6 altitudinal zones (zone 1: above 1500 m; zone 2: 1200-1300 m; zone 3: 900-1000 m; zone 4: 400-700 m; zone 5: 100-300 m; and zone 6: 0-100 m) each including three streams. The aquatic insects were identified at the lowest possible taxonomic level. The highest richness was observed in altitudes between 1200-1300 m, while the lowest occurred in altitudes below 100 m. The Indicator Value method indicated taxa characteristic for four of the six altitudinal zones considered in this paper. Sorensen's Index and CCA results showed that distribution and composition of aquatic insect fauna of Serra da Bocaina National Park was influenced primarily by altitude and temperature rather than stream size. The absence of indicator species and the lower abundance in altitudes between 400-700 m suggest a transition from rhithral to potamal fauna, which is distinct at 200 m. Resumo: Riqueza de macroinvertebrados aquáticos em riachos ao longo de um gradiente altitudinal no Sudeste do Brasil. Um estudo da riqueza e composição da fauna de insetos aquáticos de uma bacia hidrográfica com ênfase no gradiente altitudinal foi conduzido com o objetivo de testar a hipótese de que existe uma descontinuidade na composição da fauna relacionada à altitude e latitude. Na região Sudeste do Brasil, próxima à latitude 22°, a transição da fauna ritral-potamal deveria ocorrer em torno de 500 m. Com este objetivo central foram estudados 18 afluentes do Rio Mambucaba, Parque Nacional da Serra da Bocaina, SP-RJ, divididos em 6 faixas altitudinais (faixa 1: acima de 1500 m; faixa 2: 1200-1300 m; faixa 3: 900-1000 m; faixa 4: 400-700 m; faixa 5: 100-300 m e faixa 6: 0-100 m), sendo amostrados três riachos por faixa de altitude. Os insetos aquáticos foram identificados até o menor nível taxonômico possível. A maior riqueza foi observada nas altitudes entre 1200-1300 m, enquanto a menor riqueza ocorreu em altitudes inferiores a 100 m. O teste de espécies indicadoras mostrou táxons característicos para quatro das seis zonas altitudinais consideradas no presente trabalho. Os resultados do índice de Similaridade de Sorensen e da CCA mostraram que a comunidade de insetos aquáticos do Parque Nacional da Serra da Bocaina foi influenciada primariamente pela altitude e temperatura mais do que o tamanho do rio. A ausência de táxons indicat...