935 resultados para Restoration of sandbank forest


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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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Foram listadas 263 aves próximo e dentro de uma mata semidecídua de 230 ha em meio a plantações de cana-de-açúcar, na região central do Estado de São Paulo, Brasil. Subtraindo-se 67 espécies de áreas abertas, 22 de riachos, 10 vagantes e 12 observadas mais tarde, cerca de 152 espécies de mata e de borda foram observadas entre 1982-86, semelhantemente às observadas em uma mata próxima a Campinas. Ambas as matas perderam espécies gradualmente. Algumas aves evitaram as margens duras dos canaviais, preferindo as margens macias arbustivas. Das espécies de área aberta, parece que 22 desapareceram até 1997, em razão das abundantes chuvas anteriores causadas por El Niño, ou pela raridade de habitats permanentemente abertos nos canaviais; 17 espécies novas eram principalmente noturnas que não haviam sido checadas anteriormente, ou visitantes ocasionais. A mata e as bordas perderam 37 espécies, ganhando 5 de regiões secas e 1 visitante de inverno. Vários migrantes do sul apareceram somente em anos chuvosos antes do recente efeito estufa; algumas aves residentes foram caçadas, e os beija-flores das copas talvez estivessem presentes ainda. As espécies de zonas secas, prones à movimentação ou metapopulacionais, movem os centros de distribuição, camuflando parcialmente a perda de diversidade da mata úmida.

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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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Five species of titi monkey (Callicebus brunneus, Callicebus caligatus, Callicebus cinerascens, Callicebus donacophilus, and Callicebus moloch) were recorded in surveys of primate populations at 26 sites throughout the Brazilian state of Rondonia. The distribution of the two species, C. cinerascens and C. donacophilus (recorded in the state for the first time), appeared to be related to that of non-forest ecosystems, the former in the cerrado woodlands, and the latter in gallery forests of the Guapore grasslands. The results of the surveys also indicate that C. brunneus has a more restricted distribution in southern Rondonia than was previously thought, whereas C. moloch is more widespread. However, the ecological factors that determine species distribution in the south of the state remain unclear on the basis of the available data. All species were observed in small social groups of no more than five individuals, which are typical of the genus, generally in the middle and lower forest strata.

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Topography has been reported to be the major factor ruling the spatial distribution of Acrisols, Plinthosols and Gleysols on the seasonally flooded, low elevation plateaux of the upper Amazon basin occupied by Tertiary (Ica & Solimoes) sediments. In this study, detailed morphological and mineralogical investigations conducted in a representative 25-ha site were combined with hydro-geochemical data to relate the vertical and lateral soil differentiations observed to the hydro-geological history of that part of the basin. As a result of the uplift of the Andes, several cuts in the extensive Tertiary marshlands have formed, at first, slightly incised plateaux of low elevation. There, weathering under hot and humid climates would have generated a reddish, freely drained and bioturbated topsoil layer and the vertical differentiation in subsoil sediments of a plinthite over an iron-depleted mottled clay. The second episode of soil differentiation is linked to the replacement of the forest by a savannah under the drier climates of the late Pleistocene, which favours surface runoff and the infill of the incisions by fine particles. This infill, combined with the return to the present humid climate, has then enabled the local groundwater to rise on the plateaux and to generate episaturation at the topsoil/subsoil transition close to the depressions. Nowadays, ferrous iron is released from the partly iron-depleted topsoil weathering front at high water levels during the rainy seasons. It moves from footslope to low-lying positions and from top to bottom in the soil profile according to the groundwater dynamics. The present general trend is thus to the lateral export of iron at high water levels due to subsurface and overland flows, its vertical transfer during the recession of the groundwater and accumulation in a nodular plinthite. In the latter, ferrous iron is adsorbed onto its softest iron masses where it feeds the neoformation of ferrihydrite that rapidly dehydrates into haematite.

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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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We compared the relative contribution of blackwater inundation forest (igapo) and unflooded (terra firme) forest for regional bird species diversity in the lower Rio Negro region. For analyses of habitat preference we used mist-net samples and an unpublished bird species check-list. The igapo forest had lower bird species diversity than the terra firme forest. However, some 14% of the forest bird species in the region are restricted to igapo forest. Species composition was found to be distinct between the understories of the two forest types. Common forest bird guilds in the Neotropics such as ant-following birds avoid igapo forest. The differential habitat selection among birds in the inundated and unflooded forest is likely to result from vegetation structure and biological interactions such as aggressive behaviour. Since the inundated forest has a typical biota, conservation efforts needs to be directed to protect these habitats. Unfortunately, inundation forests are threatened by several human actions, especially dam construction. The extent of protected areas in the Brazilian Amazon is insufficient for the adequate protection of the inundated habitats, because it includes only 3% of the total area.

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A DNA vaccine based on the heat-shock protein 65 Mycobacterium leprae gene (pHSP65) presented a prophylactic and therapeutic effect in an experimental model of tuberculosis. In this paper, we addressed the question of which protective mechanisms are activated in Mycobacterium tuberculosis-infected mice after immune therapy with pHSP65. We evaluated activation of the cellular immune response in the lungs of infected mice 30 days after infection (initiation of immune therapy) and in those of uninfected mice. After 70 days (end of immune therapy), the immune responses of infected untreated mice, infected pHSP65-treated mice and infected pCDNA3-treated mice were also evaluated. Our results show that the most significant effect of pHSP65 was the stimulation of CD8(+) lung cell activation, interferon-gamma recovery and reduction of lung injury. There was also partial restoration of the production of tumour necrosis factor-alpha. Treatment with pcDNA3 vector also induced an immune stimulatory effect. However, only infected pHSP65-treated mice were able to produce significant levels of interferon-gamma and to restrict the growth of bacilli.

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T. micrantha (L.) Blume (Ulmaceae), a common pioneer tree species in Brazil, is used in the restoration of degraded areas. The fruits are fleshy and indehiscent, with only one water impermeable seed. During the fruiting period, fruits of different colours are found at the same time on the same branch. This research aimed to correlate fruit colour with other physical indicators of seed maturity and to Verify the effect of temperature regime on seed germination. Collected fruits were separated in to green, green-red and red colour and for each of these maturation stages, size, moisture content and dry matter of both fruits and seeds were determined. Seeds were scarified with sulphuric acid and submitted to a germination test conducted at constant (20 degreesC, 30 degreesC and 40 degreesC) and alternating (20-30 degreesC, 30-40 degreesC and 20-40 degreesC) temperatures for 15 weeks. Seed germination percentage and speed were analysed after five weeks and the fmal percentage of germinated and Viable seeds after 15 weeks. Seed maturity is attained when the fruits are green-red. At this stage, moisture content was about 64% for fruits and 10% for seeds. Alternating temperature was required for seed germination and 20-30 degreesC was the best option. Most seeds had germinated after five weeks, providing mature seeds, acid scarification and alternating temperature were used.

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Results are given of a phytosociological study of a forest located in the Morro do Diabo State Park. in the county of Teodoro Sampaio (22 degrees 31'S, 52 degrees 10'W), Pontal do Paranapanema region, state of São Paulo. The point-centered quarter method, using 300 sampling points, was used establishing 3 trails of 100 sampling points each, 10 m interdistant. All woody vegetation with a breast height diameter of 5 cm or more were samplied. Three distinct ecotopes could be identified in the forest: the lower, thc slope and the peak, which were analised separately.The families that presented the greatest numbers of genera, species and individuals were Leguminosae, Euphorbiaceae and Myrtaceae, followed by Rutaceae, Lauraceae, Meliaceae and Moracea. A total of 104 species, 85 genera and 37 families were sampled by the phytosociological survey. The relative sociological position of each plant family or species varied according to ecotope.

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Previous studies have indicated the importance of angiotensin II (ANG II) in skeletal muscle angiogenesis. The present study explored the effect of regulation of the renin gene on angiogenesis induced by electrical stimulation with the use of physiological, pharmacological, and genetic manipulations of the renin-angiotensin system (RAS). Transfer of the entire chromosome 13, containing the physiologically regulated renin gene, from the normotensive inbred Brown Norway (BN) rat into the background of an inbred substrain of the Dahl salt-sensitive (SS/Mcwi) rat restored renin levels and the angiogenic response after electrical stimulation. This restored response was significantly attenuated when SS-13BN/Mcwi consomic rats were treated with lisinopril or high-salt diet. The role of ANG II on this effect was confirmed by the complete restoration of skeletal muscle angiogenesis in SS/Mcwi rats infused with subpressor doses of ANG II. Congenic strains derived from the SS-13BN/Mcwi consomic were used to further verify the role of the renin gene in this response. Microvessel density was markedly increased after stimulation in congenic strains that contained the renin gene from the BN rat (congenic lines A and D). This angiogenic response was suppressed in control strains that carried regions of the BN genome just above (congenic line C) or just below (congenic line B) the renin gene. The present study emphasizes the importance of maintaining normal renin regulation as well as ANG II levels during the angiogenesis process with a combination of physiological, genetic, and pharmacological manipulation of the RAS.