Leptoceridae (Insecta, Trichoptera) from Serra da Canastra Mountain Range, Southeast Brazil: Diversity, Distribution, and Description of Two New Species.

The Brazilian savanna, also known as Cerrado, is one of the world's biodiversity hotspots, covering about 22% of the country. Nevertheless, this region has been suffering an accelerated process of degradation due to the agribusiness expansion. This study contributes to increasing knowledge on the Leptoceridae fauna of the Serra da Canastra Mountains at the Minas Gerais State, Brazil. Herein, we illustrate and describe two new species of Leptoceridae, Notalina franciscana sp. nov. and Oecetis catagua sp. nov., and provide additional data on the richness and distribution of Leptoceridae species in the Parque Nacional da Serra da Canastra and surrounding areas. Furthermore, ten species are firstly recorded from Minas Gerais State, increasing the number of Leptoceridae species recorded in the state from 30 to 42.

Development of a benthic multimetric index for the Serra da Bocaina bioregion in Southeast Brazil.

Brazil faces a challenge to develop biomonitoring tools to be used in water quality assessment programs, but few multimetric indices were developed so far. This study is part of an effort to test and implement programs using benthic macroinvertebrates as bioindicators in Rio de Janeiro State. Our aim was first to test the Multimetric Index for Serra dos Órgãos (SOMI) for a different area--Serra da Bocaina (SB)--in the same ecoregion. We sampled 27 streams of different sizes and altitudes in the SB region. Despite the environmental similarities, results indicated biological differences between reference sites of the two regions. Considering these differences, we decided to develop an index specific for the SB region, the Serra da Bocaina Multimetric Index (MISB). We tested twenty-two metrics for sensitivity to impairment and redundancy, and six metrics were considered valid to integrate the MISB: Family Richness, Trichoptera Richness, % Coleoptera, % Diptera, IBE-IOC index, EPT / Chironomidae ratio. A test of the MISB in eleven sites indicated it was more related to land-use and water physico-chemical parameters than with altitude or stream width, being a useful tool for the monitoring and assessment of streams in the bioregion.

Sewage input effects on the macroinvertebrate community associated to Typha domingensis Pers in a coastal lagoon in southeastern Brazil.

This study was carried out at Imboassica Lagoon, located in an urban zone in the municipality of Macaé, Rio de Janeiro state, Brazil. This lagoon has been subject to anthropogenic impacts due to the increasing city population, such as the input of sewage. Areas of variable degree of anthropogenic influence in the lagoon were compared regarding the structure of the macroinvertebrate community associated to Typha domingensis leaves. For sampling, we used 35 x 20 cm net plastic bags, with 6.8 mm mesh containing T. domingensis leaves for colonization. Two different sampling stations were selected: station A, under direct input of sewage; and station B with lesser sewage influence. The bags were removed after 20, 40 and 75 days of colonization. For each sample the Shannon-Wiever Diversity, Pielou Evenness, Jaccard Similarity Indices, Correspondence Analysis and taxonomic richness were calculated. A total of 31,874 individuals were sampled, belonging to 34 taxa. The main taxonomical groups were: Oligochaeta (41%), Chironomidae (40%), Ancylidae (4.6%), Polymitarcyidae (4%) and Thiaridae (3%). At station A, the taxonomic richness, the Evenness and Diversity values were lower than in station B. On the other hand, the total density was three times higher in station A than in B. It was already possible to discriminate the community structure of each sampling station in the first sampling. Trichoptera and Ephemeroptera were the main exclusive groups of station B and are considered good water quality indicators due to their high sensibility to contamination. The major contribution to discriminate between the macroinvertebrate communities of the two sample stations came from Chironomidae, Oligochaeta and Ephemeroptera.

Sewage input effects on the macroinvertebrate community associated to Typha domingensis Pers in a coastal lagoon in southeastern Brazil

This study was carried out at Imboassica Lagoon, located in an urban zone in the municipality of Macaé, Rio de Janeiro state, Brazil. This lagoon has been subject to anthropogenic impacts due to the increasing city population, such as the input of sewage. Areas of variable degree of anthropogenic influence in the lagoon were compared regarding the structure of the macroinvertebrate community associated to Typha domingensis leaves. For sampling, we used 35 x 20 cm net plastic bags, with 6.8 mm mesh containing T. domingensis leaves for colonization. Two different sampling stations were selected: station A, under direct input of sewage; and station B with lesser sewage influence. The bags were removed after 20, 40 and 75 days of colonization. For each sample the Shannon-Wiever Diversity, Pielou Evenness, Jaccard Similarity Indices, Correspondence Analysis and taxonomic richness were calculated. A total of 31,874 individuals were sampled, belonging to 34 taxa. The main taxonomical groups were: Oligochaeta (41 percent), Chironomidae (40 percent), Ancylidae (4.6 percent), Polymitarcyidae (4 percent) and Thiaridae (3 percent). At station A, the taxonomic richness, the Evenness and Diversity values were lower than in station B. On the other hand, the total density was three times higher in station A than in B. It was already possible to discriminate the community structure of each sampling station in the first sampling. Trichoptera and Ephemeroptera were the main exclusive groups of station B and are considered good water quality indicators due to their high sensibility to contamination. The major contribution to discriminate between the macroinvertebrate communities of the two sample stations came from Chironomidae, Oligochaeta and Ephemeroptera.

O presente estudo foi realizado na Lagoa Imboassica, localizada no perímetro urbano da cidade de Macaé, RJ, Brasil. Esta lagoa vem sofrendo impactos antrópicos com o aumento da cidade, como o aporte de esgotos sem tratamento. Areas com diferentes graus de influência antrópica na lagoa foram comparadas quanto à estrutura da fauna de macroinvertebrados associada a folhas de Typha domingensis. A amostragem da fauna foi realizada por meio de cestos de tela plástica de 35 x 20 cm e malha de 6,8 mm, com folhas de T. domingensis para colonização. Dois pontos amostrais foram selecionados: ponto A, sujeito a aporte direto de esgotos; e ponto B, sob menor influência de esgotos. Os cestos foram retirados após 20, 40 e 75 dias de colonização. Foram aplicados em cada amostra os índices de diversidade de Shannon-Wiever, equitabilidade de Pielou e similaridade de Jaccard, riqueza taxonômica e Análise de Correspondência. Foram encontrados 31.874 indivíduos, distribuídos em 34 táxons. Os principais grupos foram: Oligochaeta (41 por cento); Chironomidae (40 por cento); Ancylidae (4,6 por cento); Polimitarcyidae (4 por cento); e Thyaridae (3 por cento). No ponto A, os valores de riqueza taxonômica, equitabilidade e diversidade foram inferiores aos do ponto B. Por outro lado, a densidade total foi três vezes maior no ponto A. A estrutura da comunidade foi diferente nos dois pontos amostrais para todos os testes utilizados, desde a primeira retirada. Trichoptera e Ephemeroptera foram os principais grupos exclusivos do ponto B, sendo considerados indicadores da qualidade da água devido à sua sensibilidade. Chironomidae, Oligochaeta e Ephemeroptera foram os principais grupos a contribuir com as diferenças nas comunidades de macroinvertebrados entre os pontos amostrais.

Spatial and temporal distribution of benthic macroinvertebrates in a Southeastern Brazilian river.

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.

Spatial and temporal distribution of benthic macroinvertebrates in a Southeastern Brazilian river

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 considerando os dados dos locais de coleta indicou que a variação temporal foi o fator mais importante na estruturação das comunidades nos hábitats estudados.

Application of biological measures for stream integrity assessment in south-east Brazil.

The sensitivity of eleven metrics using macroinvertebrate assemblages were evaluated in an environmental gradient in a tropical river in south-east Brazil. Eight sites were sampled in an altitudinal range of 160-650 m.a.s.l. during 1999 (April and August) and 2000 (February). Four substrates were sampled at each site: riffle litter, pool litter, stony substrates and sediment. Correspondence Analysis indicated that assemblages were primarily more influenced by physical changes (like deforestation and erosion processes) than the water chemistry. The sensitivity of each metric was evaluated through the application of box-and-whisker plot method by its power to assess impairment (metrics should be able to discriminate reference sites from impaired sites) and natural variability (metrics should not discriminate two reference sites). Metrics that failed in at least one of the above premises were not considered as sensitive. In this study, the most sensitive metrics were Shannon index, BMWP-ASPT, %_EPT, and relative abundance of EPT to Chironomidae.

Feeding habits of chironomid larvae (Insecta: Diptera) from a stream in the Floresta da Tijuca, Rio de Janeiro, Brazil.

Chironomids larvae are frequently one of the most abundant and diverse groups of insects in several kinds of aquatic environments. Also, they play a major role in the aquatic food webs, representing a major link among producers and secondary consumers. This work investigates the feeding behavior of the chironomid larvae present in the Rio da Fazenda, situated in the Parque Nacional da Tijuca, Rio de Janeiro, Brazil, between August 1994 and May 1995. Algae, fungi, pollen, leaf and wood fragments, animal remains, detritus and silt were the main gut contents found in the larvae studied. The main food item ingested by the larvae was detritus, except for the Stenochironomus whose main food source was leaf and wood fragments. Tanypodinae exhibited a large quantity of animal remains of several kinds in the diet. During the period studied it was observed that the diet of 16 genera (out of 24 studied) varied. Tanypodinae had mainly coarse particulate organic matter (> 1 mm) in the gut contents, while Chironominae and Orthocladiinae had fine particulate organic matter (< 1 mm).

Feeding habits of Chironomid larvae (Insecta: Diptera) from a stream in the Floresta da Tijuca, Rio de Janeiro, Brazil

Chironomids larvae are frequently one of the most abundant and diverse groups of insects in several kinds of aquatic environments. Also, they play a major role in the aquatic food webs, representing a major link among producers and secondary consumers. This work investigates the feeding behavior of the chironomid larvae present in the Rio da Fazenda, situated in the Parque Nacional da Tijuca, Rio de Janeiro, Brazil, between August 1994 and May 1995. Algae, fungi, pollen, leaf and wood fragments, animal remains, detritus and silt were the main gut contents found in the larvae studied. The main food item ingested by the larvae was detritus, except for the Stenochironomus whose main food source was leaf and wood fragments. Tanypodinae exhibited a large quantity of animal remains of several kinds in the diet. During the period studied it was observed that the diet of 16 genera (out of 24 studied) varied. Tanypodinae had mainly coarse particulate organic matter (> 1 mm) in the gut contents, while Chironominae and Orthocladiinae had fine particulate organic matter (< 1 mm)

Diversity and habitat preference of aquatic insects along the longitudinal gradient of the Macaé River basin, Rio de Janeiro, Brazil.

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 1st, 2nd, 4th, 5th and 6th 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 2nd order stream reach, except for Ephemeroptera, on 4th order. However when considering morph-species taxonomic level, the higher diversity number occurred on 4th 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.

Diversity and habitat preference of aquatic insects along the longitudinal gradient of the Macaé River basin, Rio de Janeiro, Brazil

Diversity and habitat preference of macroinvertebrates were studied in MacaÚ River basin, Rio de Janeiro State, Brazil, along its longitudinal gradient. We selected stream reaches corresponding to 1st, 2nd, 4th, 5th and 6th 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 2nd order stream reach, except for Ephemeroptera, on 4th order. However when considering morph-species taxonomic level, the higher diversity number occurred on 4th 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

Variation and life strategies of the Trichoptera (Insecta) larvae community in a first order tributary of the Paquequer River, southeastern Brazil.

The Trichoptera fauna was sampled in a first order tributary of Paquequer River, in the district of Teresópolis, Rio de Janerio State. Quantitative samples of litter from pools, litter from riffles, sand, and stones were taken on each season from February 1991 to February 1992. The life cycles of common genera were categorized into three groups of biological strategies. The largest group represented the general profile of the community, in which ultimate instar larvae were predominant in spring and the younger ones in summer. Probably, emergence and oviposition occur in spring.