147 resultados para second growth forest regeneration


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Poucos estudos avaliaram em longo prazo a variação no tamanho populacional das espécies de aves em fragmentos florestais. Para avaliar a riqueza e a abundância específica da comunidade de aves de um remanescente de mata semidecidual do interior do Estado de São Paulo, sudeste do Brasil, foi conduzido o censo da avifauna florestal utilizando-se a metodologia de contagem em transecção. Estes resultados foram comparados com levantamento realizado na mesma localidade 30 anos antes, e as aves foram classificadas de acordo com suas categorias alimentares com a finalidade de associá-las à tendência ao aumento/diminuição de suas abundâncias após este intervalo de tempo. Embora tenha havido predominância de espécies com diminuição populacional, todas as categorias tróficas analisadas apresentaram também espécies com aumento em suas abundâncias. A maioria das espécies com propensão a deslocarem-se entre fragmentos apresentou diminuição em suas abundâncias. Sugerimos que, em relação a suas abundâncias específicas, as categorias tróficas são igualmente afetadas pelos processos da fragmentação, e que a regeneração florestal sofrida pelo remanescente pode ter resultado na perda de espécies de bordas. Espécies cujas abundâncias tenham reduzido neste intervalo de tempo podem sofrer extinção local futuramente.

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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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O objetivo deste trabalho foi avaliar o efeito do manejo da adubação nitrogenada sobre a cultura do sorgo granífero, cultivado solteiro e em consócio com capim-marandu e capim-mombaça, e determinar a produtividade de matéria seca das forrageiras, nos anos agrícolas 2003/2004 e 2004/2005, em plantio direto. Foi utilizado o delineamento experimental em blocos ao acaso, em arranjo fatorial 3x5, com quatro repetições. Os tratamentos consistiram de três sistemas de cultivo de sorgo granífero (solteiro e consorciado com capim-marandu ou capim-mombaça, na linha de semeadura) e cinco manejos de adubação nitrogenada: 30-70; 70-30; 50-50; 100-0; e 0-100 kg ha-1 de N, quantidades aplicadas na semeadura e na cobertura, respectivamente. O cultivo consorciado não afetou a nutrição nem a produtividade de grãos de sorgo. Apenas no primeiro ano de cultivo, o parcelamento 50-50 kg ha-1 de N proporcionou maior produtividade de grãos. O manejo da palhada interferiu no estabelecimento do sorgo no segundo ano de cultivo, e diminuiu a produtividade de grãos. As maiores doses de N aplicadas em cobertura elevaram a produtividade de matéria seca do capim-marandu e, as aplicadas em semeadura, a elevaram no capim-mombaça.

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Understanding tropical forest succession is critical for the development of tropical forest conservation strategies worldwide, given that tropical secondary forests can be considered the forests of the future. Tropical dry forests (TDF) are among the most threatened tropical ecosystems, there are more secondary forests and forest restoration efforts that require a better understanding of successional processes. The main goal of this synthesis for this special issue on the ecology and management of tropical dry forests in the Americas is to present a summarized review of the current knowledge of the ecology and management implications associated to TDF succession. We explore specific issues associated to tropical dry forest succession with emphasis on the use of chronosequences, plant diversity and composition, plant phenology and remote sensing, pollination, and animal-plant interactions; all under the integrating umbrella of ecosystem succession. We also emphasize the need to conduct socio-ecological research to understand changes in land-use history and its effects on succession and forest regeneration of TDF. We close this paper with some thoughts and ideas associated with the strong need for an integrating dimension not considered until today: the role of cyberinfrastructure and eco-informatics as a tool to support sound conservation, management and understanding of TDF in the Americas. (C) 2009 Elsevier B.V. All rights reserved.

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We studied the potential role as seed disperser of the pacu fish (Piaracrus mesopotamicus, Characidae) in the Pantanal of Brazil. The most important food item in the diet of the pacu in the wet season was fruits of the palm Bactris glaucescens found in the guts of 73 percent of all fishes collected (N = 70). We found a positive relationship between fish length, weight, and gape size and the number of intact seeds in their gut. Therefore, large pacus are especially important in dispersing B. glaucescens seeds within the studied system. Since the best seed dispersers are the largest fishes, which are preferred by commercial fisheries, we predict that the ongoing over fishing in freshwater ecosystems will have major impacts on the dispersal system of fish-dependent plants. We suggest that it is paramount to change the attitudes in fisheries management of fruit-eating fishes and urgent to evaluate the impact of fishing on forest regeneration.

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Purpose: To determine the effects of end-to-side nerve repair performed only with fibrin glue containing nerve growth in rats. Methods: Seventy two Wistar rats were divided into six equal groups: group A was not submitted to nerve section; group B was submitted to nerve fibular section only. The others groups had the nerve fibular sectioned and then repaired in the lateral surface of an intact tibial nerve, with different procedures: group C: ETS with sutures; group D: ETS with sutures and NGF; group E: ETS with FG only; group F: ETS with FG containing NGF. The motor function was accompanied and the tibial muscle mass, the number and diameter of muscular fibers and regenerated axons were measured. Results: All the analyzed variables did not show any differences among the four operated groups (p>0.05), which were statistically superior to group B (p<0.05), but inferior to group A (p>0.05). Conclusion: The end-to-side nerve repair presented the same recovery pattern, independent from the repair used, showing that the addition of nerve growth factor in fibrin glue was not enough for the results potentiating.

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Tropical rain forest conservation requires a good understanding of plant-animal interactions. Seed dispersal provides a means for plant seeds to escape competition and density-dependent seed predators and pathogens and to colonize new habitats. This makes the role and effectiveness of frugivorous species in the seed dispersal process an important topic. Northern pigtailed macaques (Macaca leonina) may be effective seed dispersers because they have a diverse diet and process seeds in several ways (swallowing, spitting out, or dropping them). To investigate the seed dispersal effectiveness of a habituated group of pigtailed macaques in Khao Yai National Park, Thailand, we examined seed dispersal quantity (number of fruit species eaten, proportion in the diet, number of feces containing seeds, and number of seeds processed) and quality (processing methods used, seed viability and germination success, habitat type and distance from parent tree for the deposited seeds, and dispersal patterns) via focal and scan sampling, seed collection, and germination tests. We found thousands of seeds per feces, including seeds up to 58 mm in length and from 88 fruit species. Importantly, the macaques dispersed seeds from primary to secondary forests, via swallowing, spitting, and dropping. Of 21 species, the effect of swallowing and spitting was positive for two species (i. e., processed seeds had a higher % germination and % viability than control seeds), neutral for 13 species (no difference in % germination or viability), and negative (processed seeds had lower % germination and viability) for five species. For the final species, the effect was neutral for spat-out seeds but negative for swallowed seeds. We conclude that macaques are effective seed dispersers in both quantitative and qualitative terms and that they are of potential importance for tropical rain forest regeneration. © 2013 Springer Science+Business Media New York.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

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Ecological processes in tropical forests are being affected at unprecedented rates by human activities. Yet, the continuity of ecological functions like seed dispersal is crucial for forest regeneration. It thus becomes increasingly urgent to be able to rapidly assess the health status of these processes in order to take appropriate management measures. We tested a method to rapidly evaluate seed removal rates on two animal-dispersed tree species, Virola kwatae and V.michelii (Myristicaceae), at three sites in French Guiana with increasing levels of anthropogenic disturbance. We counted fallen fruits, fruit valves, and seeds of each focal fruiting tree in a single 1m2 quadrat, and calculated two indices: the proportion of seeds removed and the proportion of fruits opened by mammals. They both provide an indirect and rapid assessment of frugivore activity. Our results showed a significant decrease in the proportion of removed seeds (16%) and fruits opened (19%) at the most impacted site in comparison with the other two sites (79% for seeds, 60% and 35% for fruits). This testifies to an increased impoverishment of the primate and toucan communities at the disturbed sites. This standardized protocol provides fast information about the health status of the community of seed dispersers and predators and of their seed removal services. It is time- and cost-effective and is not species-specific, allowing comparisons among sites or over time. We suggest using it with the pantropical Myristicaceae and any other capsule-producing family to rapidly assess the health status of seed removal processes across the tropics.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)