Different collecting methods reveal different ecological groups of centipedes (Chilopoda)

Soil invertebrates are studied by a number of methods. Here we used zoological methods (soil sampling, pitfall trapping, litter sifting, and hand collecting) to sample centipede communities in four floodplain forests (Czech Republic, Europe) and compared the efficiency of these methods. Heat-extraction from soil samples was the most effective, followed by pitfall trapping. The centipedes found by us can be divided into five ecological groups: 1) larger, abundant lithobiomorphs, 2) larger, scarcer lithobiomorphs, 3) smaller, soil lithobiomorphs, 4) abundant geophilomorphs, and 5) scarcer geophilomorphs.

Different collecting methods reveal different ecological groups of centipedes (Chilopoda)

Soil invertebrates are studied by a number of methods. Here we used zoological methods (soil sampling, pitfall trapping, litter sifting, and hand collecting) to sample centipede communities in four floodplain forests (Czech Republic, Europe) and compared the efficiency of these methods. Heat-extraction from soil samples was the most effective, followed by pitfall trapping. The centipedes found by us can be divided into five ecological groups: 1) larger, abundant lithobiomorphs, 2) larger, scarcer lithobiomorphs, 3) smaller, soil lithobiomorphs, 4) abundant geophilomorphs, and 5) scarcer geophilomorphs.(AU)

Fish stomach contents in benthic macroinvertebrate assemblage assessments / Conteúdo estomacal de peixes em avaliações de comunidades de macroinvertebrados bentônicos

The choice of sampling gears to assess benthic macroinvertebrate communities depends on environmental characteristics, study objectives, and cost effectiveness. Because of the high foraging capacity and diverse habitats and behaviors of benthophagous fishes, their stomach contents may offer a useful sampling tool in studies of benthic macroinvertebrates, especially in large, deep, fast rivers that are difficult to sample with traditional sediment sampling gear. Our objective was to compare the benthic macroinvertebrate communities sampled from sediments with those sampled from fish stomachs. We collected benthic macroinvertebrates and fish from three different habitat types (backwater, beach, riffle) in the wet season, drying season, and dry season along a single reach of the Grande River (Paraná River Basin, southeast Brazil). We sampled sediments through use of a Petersen dredge (total of 216 grabs) and used gill nets to sample fish (total of 36 samples). We analyzed the stomach contents of three commonly occurring benthophagous fish species (Eigenmannia virescens, Iheringichthys labrosus, Leporinus amblyrhynchus). Chironomids dominated in both sampling methods. Macroinvertebrate taxonomic composition and abundances from fish stomachs differed from those from sediment samples, but less so from riffles than from backwater and beach habitats. Macroinvertebrate taxa from E. virescens stomachs were more strongly correlated with sediment samples from all three habitats than were those from the other two species. The species accumulation curves and higher mean dispersion values, compared with with sediment samples suggest that E. virescens is more efficient than sediment samples and the other fish studied at collecting benthic taxa. We conclude that by analyzing the stomach contents of benthophagous fishes it is possible to assess important characteristics of benthic communities (dispersion, taxonomic composition and diversity). This is especially true for studies that only sample fish assemblages to evaluate aquatic ecosystem impacts. Therefore, this approach can be useful to amplify assessments of human impacts, and to incorporate additional bioindicators.(AU)

A escolha da ferramenta adequada para avaliar as comunidades de macroinvertebrados bentônicos depende dos objetivos do estudo, das características ambientais e dos recursos financeiros disponíveis. Devido à alta capacidade de forrageamento apresentada por espécies de peixes bentófagas e seu acesso a diversos tipos de habitats, a análise do conteúdo estomacal destas espécies pode ser uma ferramenta útil em avaliações de assembleias de macroinvertebrados bentônicos, especialmente em rios grandes, profundos e rápidos, que são difíceis de amostrar através de métodos convencionais de coleta de sedimento. Nosso objetivo foi comparar as assembleias de macroinvertebrados bentônicos amostrados no sedimento com as assembleias amostradas nos estômagos de espécies de peixes bentófagas. Foram coletados peixes e sedimento em três diferentes tipos de habitats (remanso, praia, corredeira) nos períodos úmido e seco ao longo de um único trecho do rio Grande (bacia do rio Paraná, sudeste do Brasil). O sedimento foi amostrado através de uma draga Petersen (total de 216 dragas) e os peixes através de redes de emalhar (total de 36 amostras). Foram analisados os conteúdos estomacais de três espécies de peixes (Eigenmannia virescens Gymnotiformes, Iheringichthys labrosus Siluriformes; Leporinus amblyrhynchus Characiformes). Chironomidae foi a família dominante em ambos os métodos. A composição taxonômica de macroinvertebrados bentônicos encontrados nos estômagos foi diferente daquela amostrada no sedimento. Os taxa de macroinvertebrados amostrados nos estômagos de E. virescens foram mais correlacionados com os três tipos de habitats do que os taxa obtidos nos estômagos das outras duas espécies. As inclinações das curvas cumulativas, assim como os maiores valores de dispersão média, demonstram que E. virescens possui potencial como ferramenta ecológica para acessar as assembleias de macroinvertebrados bentônicos, assim como os maiores valores de dispersão observados. A família Philopotamidae foi encontrada apenas no estômago de L. amblyrhynchus. Concluímos que através da análise do conteúdo do estômago de peixes é possível acessar importantes características das assembleias bentônicas (p.ex. dispersão, composição taxonômica e diversidade). Esta abordagem é especialmente verdadeira em estudos que utilizam apenas as assembleias de peixes para avaliar e/ou monitorar ecossistemas aquáticos. Desta maneira, esse enfoque pode ser útil, aumentando o conhecimento acerca dos impactos humanos sobre os ecossistemas aquáticos e contribuindo para a utilização de diferentes grupos de bioindicadores.(AU)

Equipment based on high power UV and white light LEDs to collect and observe scorpions (Arachnida: Scorpiones) and other fluorescent organisms

We introduce a new, high quality, low cost and versatile LEDs-based handset device that emits high power UV and white light, which can be used interchangeably. It offers power control and has long battery life. Even though it is optimized to detect and collect scorpions under low light conditions, it can also be used with other groups of fluorescent organisms. The device achieved superior performance in field and laboratory trials when compared with a 12 LEDs low power UV flashlight, and a 46 W black fluorescent light lamp, to locate Tityus serrulatus Lutz & Mello, 1922.

Equipment based on high power UV and white light LEDs to collect and observe scorpions (Arachnida: Scorpiones) and other fluorescent organisms

We introduce a new, high quality, low cost and versatile LEDs-based handset device that emits high power UV and white light, which can be used interchangeably. It offers power control and has long battery life. Even though it is optimized to detect and collect scorpions under low light conditions, it can also be used with other groups of fluorescent organisms. The device achieved superior performance in field and laboratory trials when compared with a 12 LEDs low power UV flashlight, and a 46 W black fluorescent light lamp, to locate Tityus serrulatus Lutz & Mello, 1922.

Equipment based on high power UV and white light LEDs to collect and observe scorpions (Arachnida: Scorpiones) and other fluorescent organisms

We introduce a new, high quality, low cost and versatile LEDs-based handset device that emits high power UV and white light, which can be used interchangeably. It offers power control and has long battery life. Even though it is optimized to detect and collect scorpions under low light conditions, it can also be used with other groups of fluorescent organisms. The device achieved superior performance in field and laboratory trials when compared with a 12 LEDs low power UV flashlight, and a 46 W black fluorescent light lamp, to locate Tityus serrulatus Lutz & Mello, 1922.

Development of a benthic multimetric index for biomonitoring of a neotropical watershed / Desenvolvimento de um Índice Multimétrico Bentônico para o biomonitoramento de uma bacia hidrográfica neotropical

Biotic indices are important tools for evaluating water quality in Biomonitoring Programmes of river basins. The objective of this study was to develop a Benthic Multimetric Index (BMI) to evaluate the water quality in a neotropical catchment in southeastern Brazil. Thirty metrics were evaluated and six were selected to calculate the BMI: family richness, percent Oligochaeta, percent Chironomidae + Oligochaeta ( percent CHOL), percent EPT (Ephemeroptera, Plecoptera and Trichoptera), percent Collector-gatherers, and BMWP-CETEC biotic index. Sampling was carried in triplicate at 21 sampling sites (8 in the river channel and 13 in the tributaries) during 4 annual collecting trips from June 2004 to November 2007, making a total of 945 samples. Scores (5, 3 or 1) were attributed to each chosen metric and were added up to establish the water quality criteria (a score of 6-12 - poor; 13-18 - intermediate; 19-24 - good; and 25-30 - very good water quality). Our results indicated that 48 percent of the sampling sites analysed in the catchment basin presented very good water quality, 14 percent good quality, 19 percent regular, and 19 percent poor water quality. This methodology proved to be an efficient tool for evaluating water quality in the Biomonitoring Programme of the Velhas River basin, and that it may serve to evaluate water quality in other river basins in South America.

Índices bióticos bentônicos são importantes ferramentas na avaliação da qualidade de água em programas de biomonitoramento de bacias hidrográficas. O objetivo deste estudo foi desenvolver um Índice Multimétrico Bentônico (IMB) para avaliar a qualidade das águas em uma bacia hidrográfica no sudeste do Brasil. Trinta métricas foram avaliadas e 6 foram selecionadas para compor o IMB: riqueza de famílias, por cento Oligochaeta, por cento Chironomidae + Oligochaeta ( por cento CHOL), por cento EPT (Ephemeroptera, Plecoptera e Trichoptera), por cento Coletores-catadores e índice BMWP-CETEC. Foram realizadas amostragens em triplicatas em 21 estações amostrais (8 na calha do rio e 13 nos tributários) em 4 coletas anuais de junho de 2004 a novembro de 2007, totalizando 945 amostras. Foram atribuídos escores (5, 3 ou 1) a cada métrica selecionada e somados para o estabelecimento do critério de qualidade de água (escore de 6 -12 - águas de qualidade ruim; 13-18 - regular; 19-24 - boa; 25-30 - muito boa). Nossos resultados mostraram que 48 por cento das estações de amostragem analisadas na bacia apresentaram águas de muito boa qualidade, 14 por cento de qualidade boa, 19 por cento regular e 19 por cento de qualidade ruim. Esta metodologia apresentou-se como eficiente ferramenta de avaliação da qualidade de água no programa de biomonitoramento da bacia hidrográfica do Rio das Velhas e poderá contribuir para a avaliação da qualidade de água de outras bacias hidrográficas na América do Sul.