Base de dados : LILACS
Pesquisa : B01.650.915 [Categoria DeCS]
Referências encontradas : 850 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 85 ir para página                         

  1 / 850 LILACS  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: lil-769591
Autor: Camargo, M.; Giarrizzo, T.; Jesus, AJS..
Título: Effect of seasonal flooding cycle on litterfall production in alluvial rainforest on the middle Xingu River (Amazon basin, Brazil) / Efeito da variação da inundação sazonal na produção de serrapilheira numa floresta aluvial do médio Rio Xingu (bacia do Amazonas, Brasil)
Fonte: Braz. j. biol;75(3s1):250-256, Aug. 2015. tab, graf.
Idioma: en.
Projeto: CNPq.
Resumo: Abstract The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flooded forests of insular lakes (Ilha Grande and Pimentel) and two flooded forests on the banks of the Xingu itself (Boa Esperança and Arroz Cru). Total litterfall correlated with rainfall and river levels, but whereas the leaf and fruit fractions followed this general pattern, the flower fraction presented an inverse pattern, peaking in the dry season. The litterfall patterns recorded in the present study were consistent with those recorded at other Amazonian sites, and in some other tropical ecosystems.

Resumo O pressuposto para este estudo foi que a produção de serrapilheira nos ambientes inundáveis do médio rio Xingu, segue um padrão de variação sazonal. Assim, se quantificou durante um ciclo anual a produção de serapilheira total e de suas frações, e se indagou a correlação entre o regime do nível do rio e a produção de serapilheira. Quatro ambientes de floresta ombrófila aluvial foram estudados: duas florestas inundáveis de lagoas insulares (Ilha Grande e Pimentel) e dois ambientes de floresta marginal no canal principal do rio Xingu (Boa Esperança e Arroz Cru). A produção de serapilheira total nos quatro ambientes mostrou um padrão sincrônico com a variação do nível do rio e com a inundação das áreas marginais. Por sua vez, foi evidente um aumento da produção de frutos durante a inundação local e de forma inversa uma maior produção de flores com o regime de seca. Os padrões registrados para os componentes de serapilheira do médio rio Xingu, confirmam os achados para outros ambientes amazônicos e tropicais.
Descritores: Inundações
Folhas de Planta/fisiologia
Floresta Úmida
Árvores/fisiologia
-Brasil
Rios
Estações do Ano
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  2 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: lil-769589
Autor: Lemos, DAN.; Ferreira, BGA.; Siqueira, JDP.; Oliveira, MM.; Ferreira, AM..
Título: Floristic and phytosociology in dense “terra firme” rainforest in the Belo Monte Hydroelectric Plant influence area, Pará, Brazil / Florística e fitossociologia de um trecho de Floresta ombrófila densa de terra firme na área de influência da Usina Hidrelétrica Belo Monte, Pará, Brasil
Fonte: Braz. j. biol;75(3s1):257-276, Aug. 2015. tab, graf.
Idioma: en.
Resumo: Abstract The objective of the present study was to characterise the floristic and phytosociological composition on a stretch of dense “Terra Firme” rainforest located in the Belo Monte hydroelectric plant area of influence, located in the state of Pará, Brazil. All trees with DAP >10 cm situated in 75 permanent plots of 1 ha were inventoried. 27,126 individuals trees (361 ind.ha-1), distributed in 59 botanical families, comprising 481 species were observed. The families with the largest number of species were Fabaceae (94), Araceae (65) and Arecaceae (43), comprising 43.7% of total species. The species Alexa grandiflora (4.41), Cenostigma tocantinum (2.50) and Bertholletia excelsa (2.28) showed the highest importance values (IV). The ten species with greater IV are concentrated (22%). The forest community has high species richness and can be classified as diverse age trees, heterogeneous and of medium conservation condition.

Resumo O presente estudo teve como objetivo caracterizar a composição florística e fitossociológica de um trecho de Floresta Ombrófila Densa de terra firme na área de influência da Usina Hidrelétrica Belo Monte, Pará, Brasil. Foram inventariadas todas as árvores com DAP > 10 cm em 75 parcelas permanentes de 1 ha. Foram observados 27.126 indivíduos arbóreos (361 ind.ha-1), distribuídos em 59 famílias botânicas, perfazendo 481 espécies. As famílias com maior número de espécies foram Fabaceae (94), Araceae (65) e Arecaceae (43), perfazendo 43,7% do total de espécies amostradas. As espécies Alexa grandiflora (4,41), Cenostigma tocantinum (2,50), Bertholletia excelsa (2,28), apresentaram os maiores valores de importância (VI), sendo que nas dez espécies com maiores IV, estão concentrados 22%. A comunidade florestal apresenta elevada riqueza florística e pode ser classificada como multiâneas, heterogêneas e com médio estado de conservação.
Descritores: Biodiversidade
Dispersão Vegetal
Floresta Úmida
Árvores/fisiologia
-Brasil
Centrais Elétricas
Responsável: BR1.1 - BIREME


  3 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886810
Autor: SOBOLESKI, VANESSA F; HIGUCHI, PEDRO; SILVA, ANA CAROLINA DA; SILVA, MARIELE A F DA; NUNES, AMANDA S; LOEBENS, RODINELI; SOUZA, KARINE DE; FERRARI, JHENIFFER; LIMA, CARLA L; KILCA, RICARDO V.
Título: Floristic-functional variation of tree component along an altitudinal gradient in araucaria forest areas, in Southern Brazil
Fonte: An. acad. bras. ciênc;89(3,supl):2219-2228, 2017. graf.
Idioma: en.
Resumo: ABSTRACT We aimed to investigate the taxonomic and functional variations of tree component of Araucaria Forest (AF) areas located along an altitudinal gradient (700, 900 and 1,600 m asl), in the southern region of Brazil. The functional traits determined were leaf area, specific leaf area, wood density, maximum potential height and dispersal syndromes and deciduousness. The data were analyzed through a functional and taxonomic dissimilarity dendrograms, community-weighted mean trait values, parametric and nonparametric tests, and Principal Component Analysis. The largest floristic-structural similarity was observed between the lower altitude areas (700 and 900 m asl), whose Bray-Curtis distance was 0.63. The area at 700 m asl was characterized by a predominance of deciduous and semi-deciduous species, with a high number of self- and wind-dispersed species, whereas the area at 1,600 m asl exhibited a predominance of animal-dispersed and evergreen species. It was also observed that there were significant variations for leaf traits, basic wood density and maximum potential height. Over all altitudinal gradient, the ordinations indicated that there was no evidence of functional differentiation among dispersal and deciduousness groups. In conclusion, the evaluated Araucaria Forest areas presented high floristic-functional variation of the tree component along the altitudinal gradient.
Descritores: Árvores/classificação
Biodiversidade
Altitude
-Especificidade da Espécie
Árvores/anatomia & histologia
Brasil
Florestas
Biomassa
Responsável: BR1.1 - BIREME


  4 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886637
Autor: GARCIA, LETÍCIA C; BARROS, FERNANDA V; LEMOS-FILHO, JOSÉ P.
Título: Environmental drivers on leaf phenology of ironstone outcrops species under seasonal climate
Fonte: An. acad. bras. ciênc;89(1):131-143, Jan,-Mar. 2017. tab, graf.
Idioma: en.
Resumo: ABSTRACT Banded iron formations (BIF) have a particular vegetation type and provide a good model system for testing theories related to leaf phenology, due to unique stressful environmental conditions. As a consequence of the stressful conditions of BIF environment, we hypothesize that most species would retain at least some significant canopy cover, even at the end of the dry season, independently of growth form - trees, shrubs, and sub-shrubs. Considering the strong seasonality, we also hypothesize that photoperiod and rainfall act as triggers for leaf fall and leaf flushing in these environments. The majority of the fifteen studied species had a semi-deciduous behavior and shed their leaves mainly during the dry season, with a recovery at the end of this season. In general, leaf flushing increased around the spring equinox (end of the dry season and start of the rainy season). A trade-off between leaf loss and leaf maintenance is expected in a community in which most plants are naturally selected to be semi-deciduous. Our results suggest photoperiod as a dominant factor in predicting leaf phenology.
Descritores: Estações do Ano
Solo/química
Clima Tropical
Folhas de Planta/fisiologia
Ferro/química
-Chuva
Temperatura
Fatores de Tempo
Árvores/fisiologia
Brasil
Fotoperíodo
Ecossistema
Responsável: BR1.1 - BIREME


  5 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886686
Autor: MENDONÇA, BRUNO A F DE; FERNANDES FILHO, ELPÍDIO I; SCHAEFER, CARLOS E G R; MENDONÇA, JÚLIA G F DE; VASCONCELOS, BRUNO N F.
Título: Soil-vegetation relationships and community structure in a "terra-firme"-white-sand vegetation gradient in Viruá National Park, northern Amazon, Brazil
Fonte: An. acad. bras. ciênc;89(2):1269-1293, Apr.-June 2017. tab, graf.
Idioma: en.
Resumo: ABSTRACT Viruá National Park encompasses a vast and complex system of hydromorphic sandy soils covered largely by the white sand vegetation ("Campinarana") ecosystem. The purpose of this study was to investigate a vegetation gradient of "terra-firme"-white sand vegetation at the Viruá National Park. Nine plots representing three physiognomic units were installed for floristic and phytosociological surveys as well as to collect composite soil samples. The data were subjected to assessments of floristic diversity and similarity, phytosociological parameters and to statistical analyses, focused on principal components (PC) and canonical correspondence analysis (CCA). The vegetation of the Campinaranas types and Forest differed in biomass and species density. Ten species, endemic to Brazil, were particularly well-represented. PC and CCA indicated a clear distinction between the studied plots, based on measured soil variables, especially base sum and clay, which were the most differentiating properties between Campinarana and Forest; For the separation of the Campinarana types, the main distinguishing variable was organic matter content and cation exchange capacity. Higher similarity of Campinaranas was associated to a monodominant species and the lower similarity of Forest was related to the high occurrence of locally rare species.
Descritores: Solo/química
Florestas
Biodiversidade
-Especificidade da Espécie
Árvores/classificação
Árvores/química
Brasil
Biomassa
Responsável: BR1.1 - BIREME


  6 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886706
Autor: LIMA, ROBSON B DE; BUFALINO, LINA; ALVES JUNIOR, FRANCISCO T; SILVA, JOSÉ A A DA; FERREIRA, RINALDO L C.
Título: Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species
Fonte: An. acad. bras. ciênc;89(2):1189-1203, Apr.-June 2017. tab, graf.
Idioma: en.
Resumo: ABSTRACT Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaike's information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.
Descritores: Árvores/crescimento & desenvolvimento
Clima Tropical
Florestas
Dispersão Vegetal/fisiologia
-Valores de Referência
Árvores/classificação
Brasil
Estatísticas não Paramétricas
Anacardiaceae/crescimento & desenvolvimento
Aspidosperma/crescimento & desenvolvimento
Caesalpinia/crescimento & desenvolvimento
Bauhinia/crescimento & desenvolvimento
Mimosa/crescimento & desenvolvimento
Biodiversidade
Mapeamento Geográfico
Responsável: BR1.1 - BIREME


  7 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886735
Autor: NETTO, SYLVIO P; PELISSARI, ALLAN L; CYSNEIROS, VINICIUS C; BONAZZA, MARCELO; SANQUETTA, CARLOS R.
Título: Sampling procedures for inventory of commercial volume tree species in Amazon Forest
Fonte: An. acad. bras. ciênc;89(3):1829-1840, July-Sept. 2017. tab, graf.
Idioma: en.
Resumo: ABSTRACT The spatial distribution of tropical tree species can affect the consistency of the estimators in commercial forest inventories, therefore, appropriate sampling procedures are required to survey species with different spatial patterns in the Amazon Forest. For this, the present study aims to evaluate the conventional sampling procedures and introduce the adaptive cluster sampling for volumetric inventories of Amazonian tree species, considering the hypotheses that the density, the spatial distribution and the zero-plots affect the consistency of the estimators, and that the adaptive cluster sampling allows to obtain more accurate volumetric estimation. We use data from a census carried out in Jamari National Forest, Brazil, where trees with diameters equal to or higher than 40 cm were measured in 1,355 plots. Species with different spatial patterns were selected and sampled with simple random sampling, systematic sampling, linear cluster sampling and adaptive cluster sampling, whereby the accuracy of the volumetric estimation and presence of zero-plots were evaluated. The sampling procedures applied to species were affected by the low density of trees and the large number of zero-plots, wherein the adaptive clusters allowed concentrating the sampling effort in plots with trees and, thus, agglutinating more representative samples to estimate the commercial volume.
Descritores: Árvores/classificação
Monitoramento Ambiental
Biodiversidade
-Especificidade da Espécie
Clima Tropical
Análise por Conglomerados
Análise Espacial
Modelos Teóricos
Responsável: BR1.1 - BIREME


  8 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-1119138
Autor: BARBOSA, Reinaldo Imbrozio; RAMÍREZ-NARVÁEZ, Perla Natalia; FEARNSIDE, Philip Martin; VILLACORTA, Carlos Darwin Angulo; CARVALHO, Lidiany Camila da Silva.
Título: Allometric models to estimate tree height in northern Amazonian ecotone forests
Fonte: Acta amaz;49(2):81-90, abr. - jun. 2019.
Idioma: en.
Resumo: Allometric models defining the relationship between stem diameter and total tree height in the Amazon basin are important because they refine the estimates of tree carbon stocks and flow in the region. This study tests different allometric models to estimate the total tree height from the stem diameter in an ecotone zone between ombrophilous and seasonal forests in the Brazilian state of Roraima, in northern Amazonia. Stem diameter and total height were measured directly in 65 recently fallen trees (live or dead). Linear and nonlinear regressions were tested to represent the D:H relation in this specific ecotone zone. Criteria for model selection were the standard error of the estimate (Syx) and the adjusted coefficient of determination (R²adj), complemented by the Akaike Information Criterion (AIC). Analysis of residuals of the most parsimonious nonlinear models showed a tendency to overestimate the total tree height for trees in the 20-40 cm diameter range. Application of our best fitted model (Michaelis-Menten) indicated that previously published general equations for the tropics that use diameter as the independent variable can either overestimate tree height in the study area by 10-29% (Weibull models) or underestimate it by 8% (climate-based models). We concluded that our site-specific model can be used in the ecotone forests studied in Roraima because it realistically reflects the local biometric relationships between stem diameter and total tree height. Studies need to be expanded in peripheral areas of northern Amazonia in order to reduce uncertainties in biomass and carbon estimates that use the tree height as a variable in general models. (AU)
Descritores: Árvores/anatomia & histologia
Resíduos/análise
Ecossistema Amazônico
Responsável: BR6.1 - BCS - Biblioteca de Ciências da Saúde


  9 / 850 LILACS  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-1119041
Autor: FRAGA, Rafael de; TORRALVO, Kelly.
Título: New record of the fringed leaf frog, Cruziohyla craspedopus (Anura: Phyllomedusidae) extends its eastern range limit
Fonte: Acta amaz;49(3):208-212, jul. - set. 2019.
Idioma: en.
Resumo: The fringed leaf frog, Cruziohyla craspedopus is rarely sampled in the Brazilian Amazon, probably due to low detection probability associated with its arboreal habit. The knowledge about the species' distribution stems from successive additions of occasional occurrence records, which indicate that the species is widely distributed throughout Amazonia. We present new occurrence records to update the geographic range of the species, which is hereby extended 224 km to the northeast. We also present morphological data from collected specimens and discuss the updated range from the geographic and ecological points of view. We show that the range of the leaf frog crosses several main tributaries along the southern bank of the Amazonas River, although the species occurrence is apparently limited by a minimum tree cover of 70%. (AU)
Descritores: Árvores
Ecossistema Amazônico
Distribuição Animal
Responsável: BR6.1 - BCS - Biblioteca de Ciências da Saúde


  10 / 850 LILACS  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo SciELO Brasil
Texto completo
Id: biblio-886848
Autor: KARIM, MARYAM; DARYAEI, MEHRDAD GHODSKHAH; TORKAMAN, JAVAD; OLADI, REZA; GHANBARY, MOHAMMAD ALI TAJICK; BARI, EHSAN; YILGOR, NURAL.
Título: Natural decomposition of hornbeam wood decayed by the white rot fungus Trametes versicolor
Fonte: An. acad. bras. ciênc;89(4):2647-2655, Oct.-Dec. 2017. tab, graf.
Idioma: en.
Resumo: ABSTRACT The impacts of white-rot fungi on altering wood chemistry have been studied mostly in vitro. However, in vivo approaches may enable better assessment of the nature of interactions between saprotrophic fungi and host tree in nature. Hence, decayed and sound wood samples were collected from a naturally infected tree (Carpinus betulus L.). Fruiting bodies of the white rot fungus Trametes versicolor grown on the same tree were identified using rDNA ITS sequencing. Chemical compositions (cellulose and lignin) of both sound and infected wood were studied. FT-IR spectroscopy was used to collect spectra of decayed and un-decayed wood samples. The results of chemical compositions indicated that T. versicolor reduced cellulose and lignin in similar quantities. Fungal activities in decayed wood causes serious decline in pH content. The amount of alcohol-benzene soluble extractives was severely decreased, while a remarkable increase was found in 1% sodium hydroxide soluble and hot water extractive contents in the decayed wood samples, respectively. FT-IR analyses demonstrated that T. versicolor causes simultaneous white rot in the hornbeam tree in vivo which is in line with in vitro experiments.
Descritores: Árvores/microbiologia
Madeira/microbiologia
Trametes/crescimento & desenvolvimento
-Árvores/química
Madeira/química
Espectroscopia de Infravermelho com Transformada de Fourier
Fenômenos Ecológicos e Ambientais
Responsável: BR1.1 - BIREME



página 1 de 85 ir para página                         
   


Refinar a pesquisa
  Base de dados : Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde