1000 resultados para southeastern Brazil -
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The non-native invasive anuran Lithobates catesbeianus is presently distributed in Brazil, especially in the Atlantic Rainforest biodiversity hotspot. Here, we use a maximum entropy ecological niche modeling algorithm (i) to model the North American native geographic distribution of this species and (ii) to project that model onto the whole of Brazil. After applying a threshold value that balances commission and omission errors, the projection results suggested high probabilities of occurrence mostly in southern and southeastern Brazil. We also present the first report on the species known distribution in Brazil, showing good agreement with model predictions. If the predictive map is interpreted as depicting invasiveness potential of L. catesbeianus, strategies to prevent further invasion in Brazil should be focused especially in the Atlantic Rainforest biodiversity hotspot.
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The ichthyofauna of 24 stretches of streams, all of 100 m length and of fifth or lower order and most of second and third order, were sampled along four left bank tributaries (Rio do Peixe, Rio Aguapei, Rio Sao Jose dos Dourados, lower Rio Tiete of the main channel of the Rio Parana in the state of São Paulo, southeastern Brazil. Sampling of the fish fauna at each of the six sites in the four basins incorporated a standardized fish collecting methodology and a standardized documentation of environmental data serving as the basis for a comparative analysis of the collecting locations. The 8,189 fish specimens collected represented six orders, 18 families, 42 genera, and 56 species, with a total biomass of 28.8 kg. Approximately 52% of the collected species were characiforms, 28% siluriforms, 9% gymnotiforms, 5% cyprinodontiforms, 4% perciforms, and 2% synbranchiforms. The most abundant of the species were the characiforms Astyanax altiparanae (15% of total) and Knodus moenkhausii (12% of total). The two species with the largest overall biomasses were A. altiparanae (34% of total biomass) and the siluriform Hypostomus sp. (8% of total biomass). Analysis of the trophic structure of the studied ichthyofauna indicated that the 10 numerically dominant species across the 24 sampled streams can be grouped into five guilds that are in decreasing order of numerical importance: omnivores, insectivores, insectivores/invertivores, periphytivores, and algivores. Species richness in the sampled stream stretches varied from six to 20 species with an average richness of 14. The species richness estimated by extrapolation for all 24 sampled stream stretches was 67 species. The Characidae are predominant among the collected specimens with approximately 50% of both individuals and biomass, a fact hypothesized to be a function of several attributes typical of the family. Six of the 56 collected species were new to science and six other species are of indefinite taxonomic status and require further analysis in order to determine their identity.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The Curitiba Basin, Parana, lies parallel to the west side of the Serra do Mar range and is part of a continental rift near the Atlantic coast of southeastern Brazil. It bears unconsolidated and poorly consolidated sediments divided in two formations: the lower Guabirotuba Formation and the overlying Tinguis Formation, both developed over Precambrian basement. Field observations, water well drill cores, and interpretations of satellite images lead to the inference that regional tectonic processes were responsible for the origin of the Basin in the continental rift context and for morphotecatonic evolution through block tilting, dissection, and erosion. The structural framework of the sediments and the basement is characterized by NE-SW-trending normal faults (extensional tectonic D-1 event) reactivated by NE-SW-trending strike-slip and reverse oblique faults (younger transtensional tectonic D-2' to transpressional tectonic D-2, event). This tectonic event, which started in the Paleogene and controlled the basin geometry, began as a halfgraben and was later reactivated as a pull-apart basin. D-2 is a neotectonic event that controls the current morphostructures. The Basin is connected to the structural rearrangement of the South American platform, which underwent a generalized extensional or trantensional process and, in late Oligocene, changed to a compressional to transpressional regime. (C) 2003 Elsevier B.V. Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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As drenagens costeiras do leste do Brasil correspondem a áreas de grande significado biogeográfico, apresentando um alto grau de endemismo em sua fauna de peixes. Padrões filogenéticos sugerem uma relação próxima entre os rios que correm para o Atlântico a os adjacentes das terras altas do escudo cristalino. Entretanto, pouco tem sido dito sobre a dinâmica dos processos geológicos relacionados aos eventos cladogenéticos entre estas áreas. Padrões de distribuição e filogenéticos sugerem uma íntima associação com a história geológica da margem continental passiva da América do Sul, desde o Cretáceo aos dias atuais. Soerguimentos macrodômicos, rifteamento, movimentos verticais entre blocos falhados e o recuo erosivo da margem leste sul-americana são considerados como as principais forças geológicas atuando sobre a distribuição da ictiofauna de água doce nestas áreas. A atividade tectônica associada à ruptura do Gondwana e separação da América do Sul e África criou seis megadomos que são responsáveis por configurar a maior parte do atual curso das principais bacias hidrográficas do escudo cristalino. Com exceção das bacias localizadas às margens de tais megadomos, estes rios desenvolveram longos e sinuosos circuitos sobre o antigo escudo cristalino brasileiro antes de desaguarem no então recentemente aberto Oceano Atlântico. Eventos cladogenéticos iniciais entre drenagens de terras altas do escudo cristalino e tributários do Atlântico podem estar associados com processos vicariantes desta fase inicial, e alguns táxons antigos, basais, grupos-irmão de táxons muito inclusivos e de ampla distribuição são encontrados nestas bacias hidrográficas. Mais tarde, a denudação erosiva generalizada resultou em um ajuste isostático da margem leste da plataforma. Tal ajuste, concomitantemente a reativações de antigas zonas de falha, resultou em movimentos verticais entre blocos falhados, dando origem, no sudeste do Brasil, a bacias tafrogênicas. Tais bacias, como a de Taubaté, São Paulo, Curitiba e Volta Redonda, entre outras, capturaram drenagens e fauna de terras altas adjacentes. Os peixes fósseis da Formação Tremembé (Eoceno-Oligoceno da Bacia de Taubaté) exemplificam este processo. Outros sistemas tafrogênicos de idade Terciária foram também identificados em outros segmentos da margem continental Atlântica, como na Província Borborema, no NE do Brasil, com marcada influência sobre o padrão de drenagem. Ao mesmo tempo, o recuo erosivo da margem leste da plataforma capturou sucessivamente rios de planalto, os quais se tornaram tributários atlânticos, evoluindo associados aos principais sistemas de falha. A natureza continuada destes processos explica os padrões filogenéticos e de distribuição miscigenados entre os tributários atlânticos e as terras altas do escudo cristalino adjacente, especialmente na margem sudeste do continente, representados por sucessivos, cada vez menos inclusivos, grupos irmãos, associados a eventos cladogenéticos desde o final do Cretáceo ao presente.
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Entre abril de 2005 e maio de 2006, através de censos seguindo os pressupostos da metodologia de transecção linear, foram estimadas a densidade populacional e abundância de Callicebus nigrifrons Spix, 1823 (Pitheciidae) no Parque Estadual da Cantareira, Estado de São Paulo, Sudeste do Brasil (23°23'42S, 46°35'27W). Com um esforço amostral de 275,8 km de censos, os sauás foram a segunda espécie de primata mais abundante, apresentando um índice de abundância de 1,4 grupos para cada 10 km percorridos e uma estimativa de densidade de 12,21 ind./km² (variando de 8,45 a 17,63 ind./km²). A coleta de dados auxiliares durante os censos possibilitou a verificação da dieta e uso do hábitat pelos grupos de Callicebus, e os resultados evidenciaram uma relativa adaptabilidade à ambientes perturbados.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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OBJETIVO: Os relatos sobre a ocorrência de raiva em morcegos no Brasil são esporádicos e isolados. Assim, o objetivo do estudo foi descrever a detecção do vírus da raiva em morcegos do Estado de São Paulo. MÉTODOS: Foram analisados 7.393 morcegos provenientes de 235 municípios do norte e noroeste do Estado de São Paulo, no período de 1997 a 2002 e identificados por meio de características morfológicas e morfométricas. Para a detecção do antígeno viral foi utilizada a técnica de imunofluorescência direta e o isolamento do vírus foi realizado por inoculação em camundongos. RESULTADOS: Das amostras examinadas, 1,3% foram positivas para raiva, com variação de 0,2% em 1997 a 1,6% em 2001. Foram encontrados 98 morcegos com o vírus, 87 deles em área urbana. O vírus da raiva foi detectado pela imunofluorescência direta em 77 do total de amostras positivas, enquanto 92 produziram doença em camundongos inoculados e o período de incubação variou entre 4-23 dias. em 43 municípios foi encontrado pelo menos um morcego positivo. Entre as espécies analisadas o vírus da raiva foi detectado com maior freqüência (33,7%) em Artibeus lituratus. Os vespertilionideos do gênero Eptesicus e Myotis totalizaram 24,5% dos morcegos positivos e as espécies do gênero Molossus (Molossus molossus e Molossus rufus), 14,3%. A distribuição do vírus da raiva foi semelhante entre fêmeas (33; 48,5%) e machos (35; 51,5%). CONCLUSÕES: Morcegos positivos para raiva foram encontrados em situações que colocam em risco tanto a população humana como animais de estimação, exigindo medidas voltadas para o manejo destas espécies e de educação da população.
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Eighteen predatory mite species of the family Phytoseiidae are reported from three sites of the Cerrado ecosystem in the State of São Paulo, southeastern Brazil, on seven plant species of the family Myrtaceae. This paper provides a list of those species and compares relevant morphological characteristics of the specimens collected with those of the original descriptions and/or redescriptions of the corresponding species. A key is provided to help in the separation of the species mentioned in the paper. Some of the species collected have been reported as common predators on dominant crops in the region where the work was done. Their occurrence on Myrtaceae plants found naturally in the Cerrado ecosystem indicates that those plants could represent important reservoirs of those predators.
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In recent years, studies based on isoenzymatic patterns of geographic variation have revealed that what is usually called the Africanized honey bee does not constitute a single population. Instead, several local populations exist with various degrees of admixture with European honey bees. In this paper, we evaluated new data on morphometric patterns of Africanized honey bees collected at 42 localities in Brazil, using univariate and multivariate (canonical) trend surface and spatial autocorrelation analyses. The clinal patterns of variation found for genetically independent characters (wing size characters and some wing venation angles) are concordant with previous studies of malate dehydrogenase (MDH) allelic frequencies and support the hypothesis that larger honey bees in southern and southeastern Brazil originated by racial admixture in the initial phases of African honey bee colonization. Geographic variation patterns of Africanized honey bee populations reflect a demic diffusion process in which European genes were gradually lost because of the higher fitness of the African gene pool in Neotropical environmental conditions.
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We studied the distribution of birds along an altitudinal gradient ranging from 800 m to 1,400 m on two slopes of the Serra do Cip6, Minas Gerais, southeastern Brazil. Ornithological surveys were conducted over transects covering open (cerrado, campo rupestre) and forested (gallery and Atlantic forest) habitats from 1994 to 2000. We found 273 bird species belonging to 51 families. Twenty-two species were restricted to higher elevations and 84 Species were detected on only one slope, depending on the vegetation type they inhabited. We recorded 104 species occurring on both slopes, while 61 species were considered altitudinal generalists. Six species, including Hyacinth Visorbearer Augastes scutatus and Cip6 Canastero Asthenes luizae were restricted to the highest parts of Serra do Cip6, a fragile habitat important to endemic birds of the Espinhaco Range. In the past 10 years, the Serra do Cip6 region has suffered human impacts on a large scale, and conservation action must be developed to protect the fauna and flora confined to the area.
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Eighteen collections of red-coloured Audouinella from Central Mexico and southeastern Brazil detected three species. The most common species, A. eugenea, is characterized by macroscopic thalli, the erect system consisting of filaments with cylindrical cells, undifferentiated into proximal and distal parts, and relatively large monosporangia (greater than or equal to 12.0 mum long). Spermatangia. and possible propagules were observed in some Mexican populations. This is the third Audouinella species observed to have gametangia and the first member of the Acrochaetiales with putative propagules. The second species, from Central Mexico, was characterized by the following features: macroscopic thalli, the erect system differentiated into proximal parts with cylindrical cells, unbranched or rarely branched, and distal parts with barrel-shaped cells, abundantly branched to form dense fascicles, with alternate or dichotomous branching, some at right-angles to the axis, and relatively large monosporangia (greater than or equal to 12.0 mum long). The morphologically distinct proximal and distal portions of the erect system, the latter forming dense fascicles, was a consistent character so far unknown in Audouinella; thus, we propose a new species, A. huastecana sp. nov. The third species is a microscopic epiphyte, A. meiospora, with a well-developed prostrate system composed of creeping and loosely aggregated filaments, and a short homogeneous erect system (less than or equal to 15 cells) of filaments with cylindrical or barrel-shaped cells and small monosporangia (less than or equal to 13.0 mum long). A. eugenea and A. meiospora are characterized for the first time from the Southern and Northern Hemispheres, respectively, both occurring mostly in areas of tropical or subtropical rainforests. A. meiospora is reported from new macroalgal hosts. A. eugenea and A. huastecana tended to occur in warm, alkaline waters with a high ion content that were moderate to fast flowing, whereas A. meiospora was not associated with particular habitats.
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The reproductive phenology of the entire climber community (96 species of lianas and 40 species of vines) in a semideciduous forest in Southeastern Brazil (22 degrees 49'45''S; 47 degrees 06'33''W and 670 m altitude) was observed from March 1988 to February 1991. Phenological observations were made weekly by walking along a 10.5 km trail in the interior and at the forest edges of the Santa Genebra Reserve (SGR). The most species-rich families of climbers were Bignoniaceae (22), Malpighiaceae (17), Sapindaceae (12) and Asteraceae (12). Flowering patterns for woody lianas and herbaceous vines differed. Lianas had two flowering peaks: a minor peak in March in the transition from wet to dry season, and a major peak in October during the transition from dry to wet season. The flowering peak for herbaceous vines was in April. Fruiting of lianas was highly seasonal, with one peak in the late dry season (July-August). Fruiting for vines was less seasonal with a slight peak in March. These differences were consistent with the predominance of wind-dispersed fruits among lianas (72% of species) versus vines (52%). Low rainfall, high leaf fall, and strong winds during the dry season favor wind dispersal. More species of vines (40%) have animal-dispersed seeds than lianas (19%), and most vines fruited during the wet season. Phenological patterns of climbers and trees and treelets at SGR differed. The life form of lianas and their system of reserve economy may allow them to reproduce during periods unfavorable to trees. Displacement of peak flowering periods of trees and climbers pollinated by bees and small generalist insects may decrease competition for pollen vectors among species of these two groups of plants. Whereas the fruiting patterns of wind-dispersed trees and climbers at SGR were similar (most species fruiting during the dry season), animal-dispersed trees and treelets fruited throughout the year while animal-dispersed climbers exhibited a pronounced peak in late wet season. The distinct phenological patterns of climbers, generally complementary to those presented by trees, resulted in constant availability of Bowers and fruits throughout the year and enhances the importance of this plant group in Neotropical forests.