25 resultados para Asurini do Xingu

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Pós-graduação em Linguística e Língua Portuguesa - FCLAR

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Por meio de observações sub e supra-aquáticas foram registradas associações alimentares do tipo nuclear-seguidor entre três espécies de peixes characiformes - Chalceus epakros, Hemiodus semitaeniatus e Hemiodus unimaculatus - e uma espécie de raia de água doce - Potamotrygon orbignyi - nas bacias dos rios Teles Pires e Xingu, no Centro-Oeste do Brasil. Os peixes teleósteos foram observados seguindo as raias quando estas revolviam o substrato à procura de invertebrados, formando discretas nuvens de sedimento. Essas situações atraíram os peixes que se aproximaram das raias para se alimentar de pequenas presas e outros tipos de alimentos expostos desta forma. Esse é um típico exemplo de relação comensal onde um participante é beneficiado enquanto o outro não é prejudicado e representa o segundo registro na literatura de associação alimentar do tipo nuclear-seguidor entre raias potamotrigonídeas e peixes teleósteos, demonstrando o potencial de estudos naturalísticos para a descoberta de novas interações envolvendo espécies de peixes de água doce.

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This study records the consequences of fire upon the soil and structure of the Amazonian Forest of Gaucha do Norte, Mato Grosso state, Brazil (13degrees12'S and 53degrees20'W). For this, the number of individuals sampled in 1 ha of the forest, during a phytosociological survey completed 2 days before the accidental fire, was compared with the survivors recorded afterwards in the reinventory of the area taken 2 days and 10 months after the fire. For the surveys, the area of 1 ha was subdivided into 50 plots of 10 m x 20 m, and all the individuals with circumference at breast height (CBH) greater than or equal to 15 cm were sampled. Chemical analysis of the 30 soil samples collected 2 days before the fire were compared with those obtained 15 days and 1 year after the fire. It was seen that, soon after the fire, there was a significant increase in the nutrient levels in the soil, an increase in the pH and a decrease in the aluminum toxicity. However, after 1 year, losses by lixiviation resulted in a nutrient reserve in the soil of less than that before the fire. The tree mortality was extremely high (23.98%), particularly amongst the younger individuals of the population (93.68% of the total of deaths in the period). There was no significant reduction in the forest richness analyzed: 60% of the species had reduced populations after the fire, but just four species were locally extinct. Results, however, demonstrated a role for fire in the selection of resistant species or those adapted to fires, since some species demonstrated a greater tolerance to the fire than others. (C) 2003 Elsevier B.V. B.V. All rights reserved.

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Este estudo apresenta a estrutura de florestas em Gaúcha do Norte-MT (13° 10'S e 53° 15' O), na borda sul-amazônica. Para o levantamento fitossociológico, três áreas amostrais de 1ha foram subdivididas em 50 parcelas de 10x20m, nas quais foram amostrados todos os indivíduos com perímetro à altura do peito (PAP) >15 cm. Para verificar a similaridade estrutural entre as áreas utilizou-se a Análise de Correspondência. As espécies indicadoras dos ambientes de interflúvio e das áreas sujeitas à inundação foram obtidas através do TWINSPAN e de um sistema de pesos. Concluiu-se que as florestas presentes na bacia do rio Pacuneiro pertencem à mesma unidade fitogeográfica, mas com subtipos florísticos e estruturais de acordo com a posição no relevo, a proximidade dos cursos d'água e o estrato analisado, apresentando predominância de algumas espécies, ou até mesmo possíveis endemismos, em determinados trechos ou estratos. A formação apresentou baixa diversidade alfa (2,91 a 3,50) e beta (3,62 a 3,86), o que não é comum em florestas amazônicas. Várias hipóteses podem explicar essa baixa diversidade, entre elas a baixa precipitação e a alta sazonalidade, o ambiente físico regional aparentemente homogêneo e favorável às espécies competidoras, ou os eventos históricos, relacionados à possível exploração por tribos indígenas ou à recente expansão dessas florestas sobre as áreas savânicas.

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Este trabalho propõe a inclusão da categoria Floresta Estacional Perenifólia no sistema oficial de classificação da vegetação brasileira, devido às particularidades florísticas e fisionômicas da floresta da borda sul-amazônica, que atinge maior amplitude geográfica na região do Alto Rio Xingu. Para justificar essa inclusão são apresentadas as características ambientais (clima, solo, hidrologia) e diferenças fisionômicas e florísticas entre as florestas do Alto Xingu e demais florestas ombrófilas da Bacia do Amazonas e estacionais do Planalto Central.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The performance evaluation it's an important procedure for recommendation of a cultivar to an specific region, because the better adapted will present superior development and bigger level of productivity. The work aimed evaluates the behavior of soybean cultivars IAC 15-1, IAC 18, IAC 20, BRS 133, FT-2000, KI-S 602 RCH, MT/BRS-55 (Uirapuru), MT/BR-45 (Paiaguas), MT/BRS-51 (Xingu), KI-S 801, MSOY 7701, MT/BR-49 (Pioneer), Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 65 (Itapoty), Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 64 (Ponta Pora), Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 61, IAC 8-2, IAC 19, Crystalline FT RCH, KI-S 702, IAC Foscarin 31, IAC-PL1 and MT/BRS-46 (Conquista), related to agronomical characteristics of plants (cycle, height, height of first beans insertion and stand) and productivity of grains, when sowed in conventional time. The experimental design was randomized blocks with four replicates, and the averages compared with Tukey Test (5%). It is viable soybean production at Selviria, MS, because practically all cultivars evaluated are adapted to the soil and climate conditions of that area. To cultivar KI-S 801, the use of smaller stand to the observed in that work it can avoid lodging. Caution should be had to use cultivar MT/BRS-55 (Uirapuru).

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White-nosed bearded sakis (Chiropotes albinasus) are endemic to the Madeira-Xingu interfluvium in southern Amazonia, though recent fieldwork has produced conflicting data on the southwestern limits of the species's geographic range. We reevaluated the distribution of bearded sakis on the basis of surveys from 34 sites throughout the Brazilian state of Rondonia. Chiropotes albinasus occurred at seven sites in the eastern part of the state, including two west of the Jiparana-Pimenta Bueno river system in the extreme south, but there is no record of their presence further north and west in the Jiparana-Guapore interfluvium and they were absent from the Jiparana-Mamore interfluvium. The data suggest that ecological, rather than geographic barriers restrict the distribution of Chiropotes albinasus in southern Rondonia, but are contradictory with regard to the possible determining factors. Chiropotes albinasus appears able to thrive in transitional, savanna-like ecosystems in southern Rondonia, but is unexpectedly absent from adjacent areas of terra firme forest. Syntopy with the only other pitheciine found in the state (Pithecia irrorata) appears to have a negative effect on the abundance of Chiropotes albinasus which implies that interspecific competition may reinforce a complex of limiting factors, such as the availability of key plant species. Despite showing that Chiropotes albinasus is widespread in southern Rondonia, we also confirm its absence from the western two thirds of the state, a significant reduction in the known range of the species.

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A total of 9 ant species were sampled from four sites covering 2000 km in the Amazon Basin using banana fruit baits: two sites on the Jurua River, one site on the Xingu River and in a dry forest of eastern Amazon, Paragominas. Camponotus abdominalis was present in all sites, and Camponotus sericeiventris, Camponotus sp. and Crematogaster sp. were present in two sites. All other species were present in only one site. Paragominas had the highest species richness because of a higher number of site restricted species. However, Jaccard faunas similarities among sites were not significantly related with distance between sites. Mosaic diversity showed a relatively simple taxonomic composition. The strong differences of the fauna sampled at banana fruit baits from other reported Neotropical ant faunas suggests that the fauna represents widespread fugitive species in an apparently complex environment.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Rhizoctonia solani causes pre- and post-emergence damping-off, root and hypocotyl rot and foliar blight in soybean. Foliar blight has resulted in yield losses of 31-60% in north and northeast Brazil. The aim of this study was to characterize isolates of R. solani associated with soybean in Brazil. Among 73 Rhizoctonia isolates examined, six were binucleate and 67 were multinucleate. The multinucleate isolates were characterized according to hyphal anastomosis reaction, mycelial growth rate, thiamine requirement, sclerotia production, and RAPD molecular markers. Four isolates that caused hypocotyl rot belonged to AG-4 and using RAPD analysis they grouped together with the HGI subgroup. Another isolate that caused root and hypocotyl rots was thiamine auxotrophic, grew at 35 °C, and belonged to AG-2-2 IIIB. All 62 isolates that caused foliar blight belonged to AG-1 IA. RAPD analysis of R. solani AG-1 IA soybean isolates showed high genetic similarity to a tester strain of AG-1 IA, confirming their classification. The teleomorph of R. solani, Thanatephorus cucumeris was produced in vitro by one AG-1 IA isolate from soybean. The AG-4 and AG-2-2 IIIB isolates caused damping-off and root and hypocotyl rots of soybean seedlings cv. 'FT-Cristalina', under greenhouse conditions. The AG-2-2 IIIB isolate caused large lesions on the cortex tissue, that was distinct from the symptoms caused by AG-4 isolates. The AG-1 IA isolates caused foliar blight in adult soybean plants cv. 'Xingu' under the greenhouse and also in a detached-leaf assay.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)