5 results on '"Henry, Raoul"'
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2. Is similar the distribution of Chironomidae (Diptera) and Oligochaeta (Annelida, Clitellata) in a river and a lateral fluvial area?
- Author
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Cesar, Daniela Aparecida Silveira, Henry, Raoul, and Universidade Estadual Paulista (Unesp)
- Subjects
Mouth zone ,sedimento ,nível da água ,Macroinvertebrates ,macroinvertebrados ,Sediment ,zona de desembocadura ,Water level - Abstract
Numerous factors may affect the pattern of distribution of benthic fauna in a river mouth region and, among the macroinvertebrates, Chironomidae and Oligochaeta are the most abundant groups and most tolerant to environmental changes. Aim The aim of this study was to evaluate the controlling factors of and a possible similarity between Chironomidae and Oligochaeta assemblies at two close sites, the mouth of the Guareí River into the Paranapanema River (São Paulo, Brazil) and its lateral fluvial area. Methods Fauna samples were collected every three months during one year. Water physical and chemical variables and sediment variables were also determined in the same period. Results Both assemblies presented low density variability over time in the lateral area due to sediment characteristics and environmental factors. Taxa Caladomyia, Parachironomus, Pristina sp., Pristina osborni, Bothrioneurum and Opistocysta funiculus were recorded at this site. The Guareí River presented both greater temporal and spatial variations, attributed mainly to a reduction in the water level. Greater organism abundance, especially of Chironomus and Tubificinae, was observed in the river. Conclusions Dissimilarity in temporal and spatial distributions of Chironomidae and Oligochaeta was attributed to peculiar characteristics of the two study sites, a river channel and a lateral area. Reduction in the water level over the year was the main controlling factor of Chironomidae and Oligochaeta richness and density in the river. In the lateral area, the presence and abundance of certain taxa were determined by the nature of the sediment and water physical and chemical variables. Resumo Diversos fatores podem afetar o padrão de distribuição da fauna bentônica em regiões de desembocadura de rios e, entre os macroinvertebrados, Chironomidae e Oligochaeta são os grupos mais abundantes e tolerantes às alterações ambientais. Objetivo O objetivo deste estudo foi avaliar a possível similaridade e os fatores controladores entre as assembleias de Chironomidae e Oligochaeta em dois locais próximos, a zona de desembocadura do rio Guareí no rio Paranapanema (SP, Brasil) e sua área fluvial lateral. Métodos As amostras de fauna foram coletadas a cada três meses durante um ano. As variáveis físico-químicas da água e sedimento também foram determinadas no mesmo período. Resultados Ambas as assembleias apresentaram baixa variabilidade temporal nas densidades na área lateral devido às características do sedimento e dos fatores ambientais. Caladomyia, Parachironomus, Pristina sp., Pristina osborni, Bothrioneurum e Opistocysta funiculus foram registradas neste local. O rio Guareí apresentou maiores variações temporais e espaciais atribuídas principalmente a uma redução no nível da água. Elevada abundância de organismos, especialmente de Chironomus e Tubificinae, foram observadas no rio. Conclusões A dissimilaridade na distribuição temporal e espacial de Chironomidae e Oligochaeta foi atribuída às características peculiares dos dois locais de estudo, o canal do rio e a área lateral. A redução do nível de água ao longo do ano foi o principal fator controlador da riqueza e densidade de Chironomidae e Oligochaeta no rio. Na área lateral, a presença e a abundância de determinados taxa foram atribuídas à natureza do sedimento e às variáveis físicas e químicas da água.
- Published
- 2017
3. Benthic distribution in small tropical lakes: the presence of macrophytes matters.
- Author
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SHIMABUKURO, ERIKA MAYUMI and HENRY, RAOUL
- Subjects
MACROPHYTES ,INVERTEBRATE communities ,CLIMATE change ,LAKES ,ABIOTIC environment - Abstract
The objective of this study was to compare the structure of macroinvertebrate communities in two lakes, one with and another without macrophytes (M+ and M-, respectively). Due to the high concentration of macrophytes into the eastern portion of the M+, we expected: (i) spatial heterogeneity of environmental variables and spatial variation of benthic composition in this lake, comparing to M-, and (ii) higher richness into the macrophytal portion (eastern portion of M+), comparing to the free macrophyte portion (western portion of M+), and also a higher richness in M+ in relation to the M-. The study was conducted in two lakes marginal to a river in Southeastern Brazil. Sampling was performed in two periods in ten sites within each lake. Three replicate samples of sediment were collected with a Van Veen grab in each site and period. Abiotic variables of water and sediment were measured at each sampling site. Macrophytes clearly determined two compartments in M+. The taxa richness was higher in the eastern portion of the M+, where the macrophytes where concentrated, and even the western portion of M+ presented higher richness than M-. Chironomus paragigas Reiss 1974 (Chironomidae) predominated in M-, a homogeneous environment. In contrast, several other taxa, such as Cryptochironomus, Cladopelma, Asheum, Dicrotendipes, Procladius occurred exclusively in the lake with macrophytes, a fragmented and heterogeneous environment. Therefore, in this study macrophytes presence induced spatial heterogeneity, reflecting in benthic macroinvertebrates' richness and distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2018
4. Chironomidae larvae associated with <italic>Eichhornia azurea</italic> leaf detritus: decomposition community structure and colonization dynamics.
- Author
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da Silva, Carolina Vieira and Henry, Raoul
- Subjects
CHIRONOMIDAE ,EICHHORNIA ,PLANT communities ,TAXONOMY ,COLONIES (Biology) - Abstract
Chironomidae stand out among aquatic insects associated with organic matter decomposition due to their abundance, cosmopolitan distribution, the varied forms in which they use detritus, as well as the feeding plasticity of their larvae. The objective of this study was to investigate the structure and composition of the Chironomidae community (Diptera) in the decomposition of
Eichhornia azurea leaves in a marginal lake. The working hypothesis is that the taxonomic and functional density and richness of Chironomidae increase over time during the degradation ofE. azurea leaves. Decomposition was analyzed in leaves kept in 2-mm mesh litter bags and collected at set successive sampling intervals. Significant differences were found in Chironomidae density and composition in the time scale. The density of individuals increased significantly during the experiment, in contrast to the taxonomic and functional richness. Subfamily Chironominae was the most representative in terms of density and taxonomic richness. The densities of taxaLabrundinia sp., Tanytarsus sp., Dicrotendipes sp., Endotribelos sp.Chironomus sp. andAblabesmyia sp. were mainly responsible for intragroup similarity in the groups formed at each sampling time. In contrast, the taxonomic composition varied throughout the experiment with characteristic ecologic succession and dynamic stabilization of the colonizing community towards the end of the experiment. In conclusion, the Chironomidae community structure presented an increase in larva density during the experimental period associated with changes in taxon composition; however, the total taxonomic richness variation was low and functional richness did not vary. [ABSTRACT FROM AUTHOR]- Published
- 2018
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5. A profundidade como fator determinante na variação anual da densidade dos macroinvertebrados associados à Salvinia auriculata Aublet
- Author
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Fulan, João Ânderson, Davanso, Rosemary Cristina, and Henry, Raoul
- Subjects
macroinvertebrates ,Odonata ,depth ,river ,Ecologia ,Limnologia ,macroinvertebrados ,profundidade ,rio - Abstract
The aim of this work was to study the effects of water annual variation of Paranapanema River and others variables on macroinvertebrates that lives in macrophytes roots, from March 2006 to February 2007. The sampled was realized with a hand-net (mesh size: 0.25 mm) and 0.07 m2 circle area. We measured air and water temperature, depth, dissolved oxygen, pH, K25 and suspended matter. The normality was tested and a Canonical Correspondence Analysis (CCA) was realized. Telebasis showed high density in period studied. There was a high variation in depth: 6.07 m in April 2006 to 1.83 m in November 2007. The CCA showed that Culicidae, Ephemeroptera, Ostracoda, Calopterygidae, Coryphaeschna and Cyanallagma were significative correlated with the depth. We concluded that the effect of the depth on larvae Odonata can not have been direct, but indirect by the effect in your substrate as aquatic plant., O objetivo deste trabalho foi estudar, no período de março de 2006 a fevereiro de 2007, o efeito da flutuação anual no nível de água do Rio Paranapanema, estado de SP, dentre outros fatores ambientais, sobre os macroinvertebrados que vivem junto às raízes de Salvinia auriculata. A amostragem da macrófita foi realizada com auxílio de um puçá com abertura em formato circular de 0,07 m2, acoplado a uma rede de malha 0,25 mm. Foram obtidos os valores da temperatura do ar e da água, a profundidade, o oxigênio dissolvido, o pH, condutividade e material em suspensão. Após a confirmação da normalidade dos dados foi realizada uma análise de correspondência canônica (ACC). Houve uma grande variação na profundidade, variando de 6,07 metros em abril de 2006 a 1,83 metros em novembro do mesmo ano. A ACC mostrou que Culicidae, Ephemeroptera, Ostracoda, Calopterygidae, Coryphaeschna e Cyanallagma foram os únicos táxons que apresentaram correlações significativas com a profundidade. O efeito da profundidade sobre as larvas de Odonata que apresentaram as maiores densidades em todos os meses estudados pode não ter ocorrido diretamente sobre os macroinvertebrados, mas sim indiretamente por afetar o substrato no qual estão presentes como as plantas aquáticas.
- Published
- 2011
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