98 resultados para Cape Sable seaside sparrow habitat


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

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

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

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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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Spermiogenesis of the domestic sparrow was investigated with the light and electron microscopes and a step by step classification is proposed. Three cell populations corresponding to early, mid and late spermatids were easily divided according to their positions in the seminiferous epithelium. In addition to this initial separation, six steps were recognized, based on nuclear morphology and the degree of chromatin condensation, in association to their acrosomal and flagellar development. Early spermiogenesis is the period previous to chromatin condensation. The first step can be recognized by the extending flagellum and the second by the pro-acrosome development in contact with the nucleus. During the third or intermediate step, chromatin condenses and the cell becomes polarized with the pro-acrosomic vesicle and the tail occupying opposite sides of the nucleus. Late spermiogenesis, including steps IV-VI, is marked by complete chromatin condensation. The final cellular modifications lead to the formation of a spiraled spermatozoon. This shape is due to the twisting of the acrosome and nucleus, as well as the helical arrangement of mitochondria around the axoneme along most of the flagellum, making an exceptionally long middle piece. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

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Seven species of marine bivalves, including six new taxa, are described from the Cape early Miocene Melville Formation which crops out on the Melville Peninsula, King George Island, West Antarctica. The bivalve assemblage includes representatives of the families Nuculidae, Ennucula frigida sp. nov., E. musculosa sp. nov.; Malletidae, Neilo (Neilo) rongelii sp. nov.; Sareptidae, Yoldia peninsularis sp. nov.; Limopsidae, Limopsis psimolis sp. nov.; Hiatellidae, Panopea (Panopea) sp. cf. P. regularis; and Pholadomyoida (Periploma acuta sp. nov.). Species studied come from four sedimentary sections measured in the upper part of the unit. Detailed morphologic features of nuculoid and areoid species are exceptionally well preserved and allow for the first time reconstruction of muscle insertions as well as dentition patterns of Cenozoic taxa. Known geological distribution of the species is in agreement with the early Miocene age assigned to the Cape Melville Formation. The bivalve fauna from Cape Melville Formation is the best known from Antarctic Miocene rocks, a time of complex geologic, paleogeographic and paleoclimatic changes in the continent. The new fauna introduces new taxonomic and palaeogeographic data that bear oil the question of opening of sea gateways and distribution of Cenozoic biota around Antarctica.

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The purpose of this work was to study fragmentation of forest formations (mesophytic forest, riparian woodland and savannah vegetation (cerrado)) in a 15,774-ha study area located in the Municipal District of Botucatu in Southeastern Brazil (São Paulo State). A land use and land cover map was made from a color composition of a Landsat-5 thematic mapper (TM) image. The edge effect caused by habitat fragmentation was assessed by overlaying, on a geographic information system (GIS), the land use and land cover data with the spectral ratio. The degree of habitat fragmentation was analyzed by deriving: 1. mean patch area and perimeter; 2. patch number and density; 3. perimeter-area ratio, fractal dimension (D), and shape diversity index (SI); and 4. distance between patches and dispersion index (R). In addition, the following relationships were modeled: 1. distribution of natural vegetation patch sizes; 2. perimeter-area relationship and the number and area of natural vegetation patches; 3. edge effect caused by habitat fragmentation, the values of R indicated that savannah patches (R = 0.86) were aggregated while patches of natural vegetation as a whole (R = 1.02) were randomly dispersed in the landscape. There was a high frequency of small patches in the landscape whereas large patches were rare. In the perimeter-area relationship, there was no sign of scale distinction in the patch shapes, In the patch number-landscape area relationship, D, though apparently scale-dependent, tends to be constant as area increases. This phenomenon was correlated with the tendency to reach a constant density as the working scale was increased, on the edge effect analysis, the edge-center distance was properly estimated by a model in which the edge-center distance was considered a function of the to;al patch area and the SI. (C) 1997 Elsevier B.V. B.V.

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In this study we present a survey on vegetative anatomy in species of Actinocephalus, Blastocaulon, Eriocaulon, Leiothrix, Paepalanthus, Philodice, Syngonanthus, and Tonina (Eriocaulaceae). Multivariate analyses were used to correlate anatomical characters to taxa and the habitats where the species occur. Root and stem anatomical characters seem to be more affected by environmental factors where these species occur, and seem of little value for delimiting major taxonomic groups within the family. Other characters in the leaves, such as epidermis with thickened wall cells, compartmented substomatal chambers, mesophyll with hypodermis, compact chlorenchyma, collenchymatous bundle sheath extensions, and numerous vascular bundles, were shown to be important for defining species clusters in Leiothrix, Syngonanthus, and Paepalanthus subg. Platycaulon. Similarly, loosely aggregated chlorenchyma caused Blastocaulon, Eriocaulon, Philodice, Syngonanthus sect. Carpocephalus, S. sect. Syngonanthus, and Tonina, genera from humid environments, to cluster. Scape characters appear to be more informative in discriminating groups. This situation probably reflects lower selection pressures determining anatomical characters of this organ.

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This study evaluated the presence and seasonal activity of free-living ticks in remaining marsh areas by the Parana river, in Brazil. Eight field trips (once per season) for collection of ticks were performed during 2 years. Using CO2 traps, dragging, and visual inspection of vegetation, five free-living tick species were collected, in the following order of abundance: Amblyomma cajennense, Amblyom\ma dubitatum, Amblyomma triste, Amblyomma coelebs, and Amblyomma nodosum. The seasonal pattern of A. cajennense was characterized by the highest peaks for adult ticks in the summer/spring months, for nymphs in the winter and for larvae in the autumn and winter. A. dubitatum and A. triste presented similar seasonal patterns characterized by peaks of adult ticks in the autumn. Nymphs of A. dubitatum peaked in the winter of the first year and in the winter/spring of the second year. A. triste was the only species to be collected in significantly higher numbers in the marsh than in surrounding drier areas such as forest patches. Among domestic animals living close the marsh areas, horses were infested by Anocentor nitens, A. cajennense, and Boophilus microplus, bovines were infested solely by B. microplus, and dogs were infested by Rhipicephalus sanguineus. Adults of A. triste showed to be well adapted to the marsh environment. This result, at least partially, explains local previous observations on the association of A. triste with marsh deer, as this vertebrate host inhabits mainly the marsh area. (c) 2006 Published by Elsevier B.V.

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The aim of the current study was to evaluate a population of Menippe nodiffons in a reef of sabellariid worms, Phragmatopoma lapidosa, with regard to recruitment, population structure and sex ratio. Sampling was carried out each other month from September 1994 up to and including July 1995, on the rocky shores of the Tenorio beach, São Paulo, Brazil. It resulted in 183 individuals, whose average carapace width in this biotope was 9.1 +/- 5.6 m. The animals were grouped in nine size classes and the frequency distribution showed that 80% occupied the three first classes. This means that the polychaete worm colonies are of great importance for the establishment of individuals in the first juvenile stages.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)