928 resultados para Research natural areas
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Concern regarding hydrological resources has been a theme of growing importance in Brazil, associating the development of new management policies and maintenance of natural areas related to rivers. An efficient way to maintain natural areas around rivers has been the development of greenways, and some cites have already adopted specific legislation in this respect. Following this growing evolution in the treatment of hydrological resources, this study was carried out to demarcate a greenway along the Corumbatai River in the state of São Paulo, Using multi-criteria analysis in a GIS environment. First, thematic maps were elaborated based on Landsat 7 satellite, aerial photographs and digital topographic base, Supported by field activities. With the use of multi-criteria analysis, for which ad hoe consultations were conducted to attribute weights to the thematic maps, a suitability map was elaborated for the allocation of the greenway. Sites that should be included in the greenway were also selected, such as areas appropriate for leisure activities, and ecologically important areas. Based on the suitability map, a pathway analysis was done, connecting the relevant points of interest, thus generating a greenway that runs along the Corumbatai River, with the aim of contributing to the conservation of this important hydrological resource. (c) 2007 Elsevier B.V. All rights reserved.
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Este trabalho mostra os resultados obtidos com a realização de ensaios geofísicos na em áreas de lavra de areia, no município de Descalvado, SP. O objetivo dos ensaios é o de detectar cavidades no interior de arenitos, pertencentes às Formações Pirambóia e Botucatu. Estas cavidades formaram-se com o rebaixamento do lençol freático, necessário para as operações de extração da areia. As técnicas geofísicas utilizadas foram: gravimetria, eletrorresistividade (caminhamento elétrico dipolo-dipolo) e radar de penetração no solo (GPR). Na primeira etapa dos trabalhos foram utilizados a gravimetria e a eletrorresistividade em uma bancada onde ocorreu um desmoronamento devido ao abatimento do teto de uma cavidade. Os resultados obtidos com estas duas técnicas foram coerentes pois a gravimetria mostrou baixos gravimétricos indicando uma ausência de massa na área de influência da cavidade e o caminhamento detectou um esperado aumento de resistividade elétrica nesta mesma área. Na segunda etapa, com a realização dos ensaios de GPR em uma bancada próxima à anterior, foi possível detectar cavidades por meio das feições hiperbólicas detectadas nos radargramas.
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Áreas agrícolas trocam enormes fluxos de CO2, oferecendo uma oportunidade para mitigar o efeito estufa. Neste trabalho, estudou-se o potencial de sequestro de carbono em razão da conversão no manejo das principais atividades agrícolas do Brasil. Dados de vários estudos têm indicado que no sistema soja/milho e nas respectivas rotações, ocorre um sequestro de carbono no solo significativo ao longo dos anos de conversão do plantio convencional para o plantio direto, com uma média de 0,41 Mg C ha-1 ano-1. O mesmo efeito tem sido observado nos canaviais, porém há maiores acúmulos de carbono no solo quando as áreas de cana-de-açúcar são convertidas da colheita baseada na queima para a mecanizada, em que grandes quantidades de palha são deixadas na superfície do solo (1,8 Mg C ha-1 ano-1). Esse maior potencial de acúmulo de carbono no solo nos canaviais, comparado com outras culturas, está diretamente relacionado com a maior produção primária dessa cultura. Apesar disso, muito desse potencial de sequestro é perdido, uma vez que os canaviais são reformados, sob preparo intensivo do solo. As áreas de pasto mostram uma depleção nos estoques de carbono, quando convertidas de áreas naturais; porém, a integração dessas áreas com agricultura pode promover o aumento nos estoques de carbono do solo. Os trabalhos têm mostrado que as principais atividades agrícolas do Brasil possuem um grande potencial de mitigação, especialmente na forma de acúmulo de carbono no solo, sendo uma oportunidade para estratégias futuras.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The geographic area of the present study corresponds to the basin of the Itiquira river high course (Figure 1), in the portion that extends from the tributaries of its source, in the east of the plateau Correntes/Itiquira, in the neighbourhoods the city of Alto Garç as, to the scarp of the São Jerônimo mountain range, toward the west of Itiquira, in the state of Mato Grosso, totalizing 5,361 km 2. The area is placed in the eastern part of the Alto Paraguai basin, in the western portion of the Paraná Sedimentary Basin plateau. Through GIS techniques, it was possible to asses total soil losses from the Itiquira river basin, considering the years of 1966, 1985 and 1996, being based on the Universal Soil Loss Equation. Thus, in 1966 the basin lost 201,546.94 ton of soil, with an average loss of 0.37 ton/ha/year. Considering that the total area of the Itiquira river basin is of 536,100 ha, while in 1985 the soil losses had passed to 1,760,833.40 ton, with an increase of approximately 8.5 times. The average of soil losses in 1985 was of 3.28 ton/ha/year. In 1996 the basin lost 1,662,043.24 ton, with a reduction of only 9.4% in relation to 1985 but, in relation the 1966, the increase continued in the order of 8 times. The average losses per hectare in this year was in the order of 3.10 ton/ha/year (Chart 1). The map of potential of the laminar erosion for 1966 (Figure 3), shows to the highest values in small areas, situated in the northeast of the area, in Alto Garças, with values between 10 the 20 ton/ha/year and some spots in sources of the Itiquira and Ariranha rivers, with values between 1 the 5 ton/ha/year. In a general way, however, the area presents low soil loss for laminar erosion in this year, with inferior values to 1 ton/ha/year. The higher class of erosion, over 10 ton/ha/year, occupied 2,947 ha in 1966. In the year of 1985 (Figure 4), the erosive process spread over the entire studied area, and the class of erosion over of 10 ton/ha/year, already started to occupy 78,437 ha, implying an increase of approximately 27 times in 19 years. A strong increment in the erosive process was noticed in the western part of the area, to along the BR-163 road, exactly where great areas of natural vegetation (open pasture) had been transformed in culture and pasture areas. In the north-eastern part of the area it was also noticed an increment in the erosive process in agreement with the increase of culture areas and reduction of the natural areas, but it was not of so intense form as in the western portion of the area. In the year of 1996 (Figure 5), the class of erosion over of 10 ton/ha/year had diminished for a total of 53.499 ha noticing a retraction of the erosive process in the western part of the area, alongside the BR-163 road. On the other hand, it occurred a strong increment in the northern part of the area, in the neighbourhoods of the city of Alto Garças, alongside the BR-364 road and part of the MT-040 road. In a general way, in the outskirts of the city of Itiquira, in the central part of the area, it was verified an increase of the amount of zones with erosion between 0-1 ton/ha/year, passing to the immediately superior class, of 1-3 ton/ha/year; scarce data of hydrosedimentology in the UHE Itiquira (1999), shows good agreement with the values gotten for the EUPS (Chart 2). Based on the hydric classification proposal for FAO (1967) (Chart 3), it is noticed that areas with high degree of erosion (> 50) in the analysed area are very restricted, occupying 493 ha in 1985 and 332 ha in 1996 (Chart 4). In 1996 appeared as isolated spots in the north of Itiquira and Alto Garças, however beyond limits of the Itiquira river basin. These areas require special cares in its use as agricultural areas. Aiming at identifying and indicating the areas of potential risk of erosion and that need implementation of conservation practices, it was elaborated the map of limit of tolerance to the soil losses. In 1966 (Figure 6), areas with soil losses over of the tolerable were restricted to small spots located in the eastern part of the area, occupying 0.43% of the total of the area; already in 1985 (Figure 7), this percentage passed to 5.86%, spreading for all the area; in 1996 (Figure 8) it is observed a fast reduction of the areas with soil losses over of the tolerance limit, passing 5.43% of the total of the area. All the areas with losses over of the tolerable value must be considered as risk areas and were done in these areas studies for implementation of conservation practices.
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Preserving large tracts of natural habitats is essential to maintain biodiversity. Nevertheless, even large areas may still suffer from less visible impacts such as loss of ecological processes. Because mapping ecological processes over large scales is not practical, an alternative is to map surrogate species that are key for those processes. In this study, we chose four species of Neotropical large mammals (the largest apex predator: jaguar - Panthera onca; the largest herbivore: tapir - Tapirus terrestris; the largest seed predator: white-lipped peccary - Tayassu pecari; and the largest arboreal seed disperser: muriqui - Brachyteles spp.) in an ecosystem with an old history of human impact (the Atlantic Forest) to test whether areas with native forest still harbor ecological processes that may guarantee long-term ecosystem maintenance. We gathered 94 locations with recent presence of the four species to map current ranges and model suitable areas. Our results reveal that 96% of the remaining Atlantic Forest is depleted of at least one of the four surrogate species and 88% is completely depleted of all four surrogate species. We also found that only 16% is still environmentally suitable for all four, and 55% is completely unsuitable to all four of them. Our study highlights the importance of looking beyond land cover to fully depict intactness of natural areas, and suggests that ecosystems with a long history of human impact (such as the Atlantic Forest) may be suffering from ecological impacts not seen at a first glance. © 2013 Elsevier Ltd.
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Pós-graduação em Geociências e Meio Ambiente - IGCE
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Apis mellifera honeybees are social insects of economic importance, by providing honeybee products, and by the pollination of natural areas of vegetation or agricultural areas. The constant use of pesticides, including the thiamethoxam, which is an insecticide belonging to the class of neonicotinoids with neurotoxic action, is subjecting pollinators to situations of severe stress, which has been evidenced by the decrease in the density of honeybees in many parts of the world. By these considerations, the present study aimed to assess the acute toxicity of thiamethoxam for newly emerged workers of A. mellifera, and to investigate the effect of sublethal doses of this insecticide on the survival time and its cytotoxicity to the brain and midgut to the honeybees. It was established the value of the lethal concentration 50 (LC50) equal to 4.28 ng thiamethoxam/μL of food and from it, the sublethal concentrations of 0.428 ng thiamethoxam/μL (CL50/10) and 0.0428 ng thiamethoxam/μL (CL50/100), which were used in bioassays of intoxication of the honeybees. After the bioassays the bees were dissected and the brain and midguts were collected to analyze possible morphological (staining with Hematoxylin-Eosin) and histochemical alterations (Xylidine Ponceau technique, and Feulgen and PAS reactions) caused by exposure to thiamethoxam, and to calculate the lethal time (LT50) for the workers. The duration of the bioassays was 8 days after beginning of feeding. The results obtained showed that the thiamethoxam is toxic to newly-emerged workers of A. mellifera, causing changes in survival time of individuals. This study also shown that the thiamethoxam causes morphological and histochemical alterations on the midgut and brain of workers. These alterations may be reflected in physiological and behavioral changes that can modify the operation of the colony
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The medium to large-sized mammals make population control of invertebrates and vertebrates, as well as seed dispersers are also important. Are losing territory and living area because of deforestation and fragmentation of natural areas, mainly in the Atlantic Forest. The RPPN Amadeu Botelho, in the municipality of Jaú, São Paulo State, is one of the last forest remnants of interior paulista. It is isolated from other forest fragments and thus is a wildlife refuge in the region of Jaú, Midwest of the State. Animals as Pumas (Puma concolor), ocelot (Leopardus pardalis), cat-Moorish (Puma yagouaroundi), have already been sighted in the reserve by officials and residents. The buffer property of the farm Santo Antônio dos Ipês, is surrounded by several plantations, and is very close to the Centre of the city of Jaú. In addition to the lifting of the reservation, it sized mammal species diagnosed the influences that the activities of the farm and the proximity to the Centre of the municipality of Jaú exert to fauna studied
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As we focusing in the Brazilian rural area we see that it presents the spatial diversity and the different organization forms of the space arising from its diversity, tied to the different economic, social, politic and cultural contexts .These contextual diversities bring results that is not limited to the agrarian sector, but get beyond the border of the rural world, taking different ways of organization and structuring in the urban areas. The building and management of the rural spaces are constituted as an attribute of the agricultural production that in the course of the centuries made disappear and reduce significant proportions from the natural areas. In many places, the intensification of the production process gives satisfaction to the globalized markets and that return allows the reproduction of the productive conditions. In other areas the access difficulties to the market and the proximity to the developed urban centers cause the abandonment of the agricultural activity and the maintenance of property without production or with specific services (tourism, for example). That process triggers a multiplicity of factors that are defining the pace of the rural areas in Brazil. This work sought to understand all the deals of the ‘’rural’’ county of Rio Claro-SP and what’s the role and the situation that we find the familiar agriculture in the advanced urban areas, which is the case of this study. Where the agriculture doesn’t represent the flagship of the economy. It was the intention, identify what activities and practices socio-spatial are developed in the county rural area. Trying to understand the public politics acts in the promotion and encouragement to the already developed activities or even other activities that can represent the possibility of a social and territorial reproduction of the families on the country
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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)