616 resultados para Rainforest planations


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OBJECTIVES To identify the aetiological agents of cutaneous leishmaniasis and to investigate the genetic polymorphism of Leishmania (Viannia) parasites circulating in an area with endemic cutaneous leishmaniasis (CL) in the Atlantic rainforest region of northeastern Brazil. METHODS Leishmania spp. isolates came from three sources: (i) patients diagnosed clinically and parasitologically with CL based on primary lesions, secondary lesions, clinical recidiva, mucocutaneous leishmaniasis and scars; (ii) sentinel hamsters, sylvatic or synanthropic small rodents; and (iii) the sand fly species Lutzomyia whitmani. Isolates were characterised using monoclonal antibodies, multilocus enzyme electrophoresis (MLEE) and polymerase chain reaction-restriction fragment length polymorphism of the internal transcribed spacer region rDNA locus. RESULTS Seventy-seven isolates were obtained and characterised. All isolates were identified as Leishmania (Viannia) braziliensis serodeme 1 based on reactivity to monoclonal antibodies. MLEE identified 10 zymodemes circulating in the study region. Most isolates were classified as zymodemes closely related to L. (V.) braziliensis, but five isolates were classified as Leishmania (Viannia) shawi. All but three of the identified zymodemes have so far been observed only in the study region. Enzootic transmission and multiclonal infection were observed. CONCLUSIONS Our results confirm that transmission cycle complexity and the co-existence of two or more species in the same area can affect the level of genetic polymorphism in a natural Leishmania population. Although it is not possible to make inferences as to the modes of genetic exchange, one can speculate that some of the zymodemes specific to the region are hybrids of L. (V.) braziliensis and L. (V.) shawi.

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Parasites of wild primates are important for conservation biology and human health due to their high potential to infect humans. In the Amazon region, non-human primates are commonly infected by Trypanosoma cruzi and T rangeli, which are also infective to man and several mammals. This is the first survey of trypanosomiasis in a critically endangered species of tamarin, Saguinus bicolor (Callitrichidae), from the Brazilian Amazon Rainforest. Of the 96 free-ranging specimens of S. bicolor examined 45 (46.8%) yielded blood smears positive for trypanosomes. T rangeli was detected in blood smears of 38 monkeys (39.6%) whereas T. cruzi was never detected. Seven animals (7.3%) presented trypanosomes of the subgenus Megatrypanum. Hemocultures detected 84 positive tamarins (87.5%). Seventy-two of 84 (85.7%) were morphologically diagnosed as T rangeli and 3 (3.1%) as T. cruzi. Nine tamarins (9.4%) yielded mixed cultures of these two species, which after successive passages generated six cultures exclusively of T. cruzi and two of T rangeli, with only one culture remaining mixed. Of the 72 cultures positive for T rangeli, 62 remained as established cultures and were genotyped: 8 were assigned to phylogenetic lineage A (12.9%) and 54 to lineage B (87.1%). Ten established cultures of T. cruzi were genotyped as TCI lineage (100%). Transmission of both trypanosome species, their potential risk to this endangered species and the role of wild primates as reservoirs for trypanosomes infective to humans are discussed. (C) 2008 Elsevier B.V. All rights reserved.

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The Amazon is one of the few continental regions where atmospheric aerosol particles and their effects on climate are not dominated by anthropogenic sources. During the wet season, the ambient conditions approach those of the pristine pre-industrial era. We show that the fine submicrometer particles accounting for most cloud condensation nuclei are predominantly composed of secondary organic material formed by oxidation of gaseous biogenic precursors. Supermicrometer particles, which are relevant as ice nuclei, consist mostly of primary biological material directly released from rainforest biota. The Amazon Basin appears to be a biogeochemical reactor, in which the biosphere and atmospheric photochemistry produce nuclei for clouds and precipitation sustaining the hydrological cycle. The prevailing regime of aerosol-cloud interactions in this natural environment is distinctly different from polluted regions.

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Quasi-simultaneous vertically resolved multiwavelength aerosol Raman lidar observations were conducted in the near field (Praia, Cape Verde, 15 degrees N, 23.5 degrees W) and in the far field (Manaus, Amazon basin, Brazil, 2.5 degrees S, 60 degrees W) of the long-range transport regime between West Africa and South America. Based on a unique data set (case study) of spectrally resolved backscatter and extinction coefficients, and of the depolarization ratio a detailed characterization of aerosol properties, vertical stratification, mixing, and aging behavior during the long-distance travel in February 2008 (dry season in western Africa, wet season in the Amazon basin) is presented. While highly stratified aerosol layers of dust and smoke up to 5.5 km height were found close to Africa, the aerosol over Manaus was almost well-mixed, reached up to 3.5 km, and mainly consisted of aged biomass burning smoke. Citation: Ansmann, A., H. Baars, M. Tesche, D. Muller, D. Althausen, R. Engelmann, T. Pauliquevis, and P. Artaxo (2009), Dust and smoke transport from Africa to South America: Lidar profiling over Cape Verde and the Amazon rainforest, Geophys. Res. Lett., 36, L11802, doi: 10.1029/2009GL037923.

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The long-term Colonia record is located in the Atlantic rainforest domain in Brazil (23 degrees 52`S 46 degrees 42`20 `` W 900 m a.s.l.). The 780 cm long core CO3 provides a coverage of a complete interglacial/glacial cycle for the first time in a neotropical rainforest. Information on the behavior of tropical climates compared to global changes in temperatures indicates specific climate responses in terms of precipitation at these latitudes. Winter extratropical circulation was very active during the last interglacial and most of the glacial. Floristic composition of the rainforest changed several times in each phase of expansion, twice during the interglacial, and three times during glacial episodes. Araucaria was well developed in the area of Sao Paulo until the beginning of the first dry phase of the glacial at ca. 50,000 yr B.P. Changes in insolation controlled the expansion of the rainforest and the tropical hydrological cycle as evidenced by a strong precession signal. However precession had no impact on regional climatic features. The two interglacials (MIS 5e and Holocene) showed completely different patterns attesting to the continuous evolution of the forest. The biodiversity index (Shannon-Wiener Index) remained high during both the interglacial and glacial attesting to the permanence of small patches of rainforest refugia during drier phases. The lowest Shannon-Wiener Indexes were recorded between 23,000 and 12,000 yr B.P. and 40,000 and 30,000 yr B.P. and characterize two marked phases of stress for the rainforest. (C) 2008 Elsevier B.V. All rights reserved.

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Epiphytic bryophytes of the Soft Tree-fern Dicksonia antarctica Labill. were examined in four Cool Temperate Rainforest pockets of the Central Highlands of Victoria. Thirty-two species, 17 mosses and 15 liverworts, were noted. There was no distinction in species assemblage between the north and south side of tree-ferns although bryophytes occurred on the south side of more tree-ferns than they did on the north side.

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This study investigated the epiphytic communities on Myrtle Beech Nothofagus cunninghamii (Hook.) Oerst. and Mountain Ash Eucalyptus regnans F.Muell. trees in a pocket of Cool Temperate Rainforest in the Yarra Ranges National Park, Victoria, Australia. Twenty species were identified growing on N. cunninghamii, with nine species found on E. regnans. The dominant epiphytes were the moss Dicranoloma menziesii on N. cunninghamii, and the liverwort Bazzania adnexa var. adnexa on E. regnans.

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Lichen floristics and distribution were examined in cool temperate rainforests of Victoria, Australia. Forty sites were sampled, ten from each of the Otways, Yarra Ranges, Baw Baw, and Errinundra regions. A total of 165 lichen species were recorded, representing 38 fam- ilies. Seventeen species are new for Victoria. Non-metric Multidimensional Scaling showed three lichen groups that corresponded with the rainforest types in which they occurred. A sub-group of lichen species were considered widespread and represented the core of Victoria's rainforest lichen flora.

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Damage caused by Sambar, particularly browsing, antler rubbing and physical removal of particular plant species, is resulting in serious ecological consequences. Threatening processes instigated or maintained by Sambar include: loss of individual taxa, altered vegetation structure and massive
widespread removal and prevention of regeneration, which is now resulting in the loss of plant communities in some areas. These observations are particularly disturbing, as it is apparent that Sambar are yet to reach their full ecological and population potential in south-eastern Australia. The destruction documented ill this article is now so widespread and so severe that in places it represents an ecological disaster for specific plant and animal species, ecological vegetation classes and floristic communities. We strongly recommend that Sambar in particular, and feral deer in general. should no longer be protected under the Wildlife Act 1975 so that control methods can be devised and implemented. It now appears that such measures will he essential for the long-term survival of some fragile plant species and communities in Victoria. (Title: Victorian Naturalist 122(4) 2005, 189-200

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We explored lichen species richness and patterns of lichen succession on rough barked Nothofagus cunninghamii trees and on smooth barked Atherosperma moschatum trees in cool temperate rainforests in Victoria, Australia. Nothofagus cunninghamii trees from the Yarra Ranges, and A.moschatum trees from Errinundra were ranked into size classes (small, medium, large and extra-large), and differences in species richness and composition were compared between size classes for each tree species. Nothofagus cunninghamii supported a rich lichen flora (108 trees, 52 lichen species), with the largest trees supporting a significantly higher number of species, including many uncommon species. This success was attributed to varying bark texture, stand characteristics and microhabitat variations as the trees age. Atherosperma moschatum supported a comparable number of species (120 trees, 54 lichen species). Indeed on average, this host supported more lichen species than N. cunninghamii. However, successional patterns with increasing girth were not as clear for A. moschatum, possibly due to the more stable microclimate that this smooth barked host provided. Victorian cool temperate rainforests exist primarily as small, often isolated pockets within a sea of Eucalypt-dominated, fire-prone forest. Many are regenerating from past disturbance. We find that protection of Victoria’s oldest rainforest pockets is crucial, as they represent sources of rare, potentially threatened lichen species, and may be acting as reservoirs for propagules for nearby ageing rainforests. Indeed, even single, large old trees have conservation importance, as they may provide exceptional microhabitats, not found elsewhere in the regenerating rainforest environment.


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)