946 resultados para Environmental impacts.


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Across the Earth, mangroves play an important role in coastal protection, both as nurseries and carbon sinks. However, due to various human and environmental impacts, the coverage of mangroves is declining on a global scale. The Red Sea is in the northern-most area of the distribution range of mangroves. Little is known about the surface covered by mangroves at this northern limit or about the changes experienced by Red Sea mangroves. We sought to study changes in the coverage of Red Sea mangroves by using multi-temporal Landsat data (1972, 2000 and 2013). Interestingly, our results show that there has been no decline in mangrove stands in the Red Sea but rather a slight increase. The area covered by mangroves is about 69 km**2 along the African shore and 51 km**2 along the Arabian Peninsula shore. From 1972 to 2013, the area covered by mangroves increased by about 0.29%/y. We conclude that the trend exhibited by Red Sea mangroves departs from the general global decline of mangroves. Along the Red Sea, mangroves expanded by 12% over the 41 years from 1972 to 2013. Losses to Red Sea mangroves, mostly due to coastal development, have been compensated by afforestation projects.

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El presente trabajo tiene como objetivo demostrar la importancia de la hidrovía Paraná‐Paraguay dentro del contexto del Mercosur. Esta obra de infraestructura es un elemento clave para la integración física efectiva, ya que permite expandir el desarrollo comercial de la región, reduciendo los costos de transporte. Por sus características, la hidrovía es una de las principales vías fluviales de navegación del mundo, tanto por su longitud como por su caudal. Los gobiernos tanto de Argentina como de Brasil y Paraguay, impulsaron la expansión de la hidrovía Paraguay‐ Paraná, porque lo consideraron un dinamizador potencial de las economías regionales. Los países del Mercosur invirtieron, y probablemente seguirán invirtiendo miles de millones de dólares en la ampliación y modernización de su infraestructura portuaria en los próximos años, más aún cuando consideren que la profundización de la integración también pasa, en gran parte, por la integración hídrica. Dado que la hidrovía es financiada por el sector público, sector privado y organismos internacionales de crédito, sumado ello al controvertido impacto ambiental de las obras, se han generado debates y resistencia al avance de las obras, por parte de organismos no gubernamentales dedicados al medio ambiente. Sin embargo, este debate todavía está inconcluso, así también como las obras, que todavía se encuentran en proyecto de ejecución.

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Fil: Almeida, Rosemeire Ap. de. Universidade Federal do Rio Grande do Sul (Brasil)

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Planned to be a process of early evaluation of Politics, Plans and Programs (PPPs), which interfere in the environment; the Strategic Environmental Assessment (SEA) suggests a methodology for planning and managing the land, which overcomes the limitations of the traditional plans that try to mitigate the environmental impacts of Projects, assuming a pro-active conception that incorporates the social and environmental aspects in the planning stage of the PPPs. This kind of Evaluation surpasses the existing limitations of the Environmental Impact Assessment (EIA), once the EIA happens after the planning process, when lots of decisions have been made and carried out. In order to overcome the limitations of EIA, the SEA is a strategic tool in the process of planning and managing the land. When we focus on the PPPs and not on the Projects, the SEA, which is more political than technical, priorizes the strategies that assure the integration of the environmental, social, economic and institutional aspects into the planning process, in private or public organizations. In this context, this work aims to establish the concept basis of the Strategic Environmental Evaluation as a tool for land planning and managing. The methodology procedures used here lie in the literature review concerning the SEA, analyzing how this tool can be introduced as an alternative for sustainable development. Although the SEA is a tool that introduces the sustainable development theme as a guiding principle of planning, it is seldom used by managers and decision makers, locally and nationally

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The coastal systems, are often subjected to high anthropogenic pressure, which makes it necessary to develop new techniques to assess the environmental impacts caused by such human activity. This paper presents the first results obtained during the development and implementation of a new equipment of submarine geophysics survey oriented to integrated coastal zone management (ICZM). It is based on the drag of a submarine in contact with the sea-bottom. The submarine is equipped with an electromagnetic sensor which allows the measurement of the magnetic susceptibility and electrical conductivity of the surface sediments continuously and to a depth of sediment of 40 cm. This system, once improved, will allow us to obtain valuable information for monitoring the environmental quality of coastal areas.

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Planned to be a process of early evaluation of Politics, Plans and Programs (PPPs), which interfere in the environment; the Strategic Environmental Assessment (SEA) suggests a methodology for planning and managing the land, which overcomes the limitations of the traditional plans that try to mitigate the environmental impacts of Projects, assuming a pro-active conception that incorporates the social and environmental aspects in the planning stage of the PPPs. This kind of Evaluation surpasses the existing limitations of the Environmental Impact Assessment (EIA), once the EIA happens after the planning process, when lots of decisions have been made and carried out. In order to overcome the limitations of EIA, the SEA is a strategic tool in the process of planning and managing the land. When we focus on the PPPs and not on the Projects, the SEA, which is more political than technical, priorizes the strategies that assure the integration of the environmental, social, economic and institutional aspects into the planning process, in private or public organizations. In this context, this work aims to establish the concept basis of the Strategic Environmental Evaluation as a tool for land planning and managing. The methodology procedures used here lie in the literature review concerning the SEA, analyzing how this tool can be introduced as an alternative for sustainable development. Although the SEA is a tool that introduces the sustainable development theme as a guiding principle of planning, it is seldom used by managers and decision makers, locally and nationally

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Planned to be a process of early evaluation of Politics, Plans and Programs (PPPs), which interfere in the environment; the Strategic Environmental Assessment (SEA) suggests a methodology for planning and managing the land, which overcomes the limitations of the traditional plans that try to mitigate the environmental impacts of Projects, assuming a pro-active conception that incorporates the social and environmental aspects in the planning stage of the PPPs. This kind of Evaluation surpasses the existing limitations of the Environmental Impact Assessment (EIA), once the EIA happens after the planning process, when lots of decisions have been made and carried out. In order to overcome the limitations of EIA, the SEA is a strategic tool in the process of planning and managing the land. When we focus on the PPPs and not on the Projects, the SEA, which is more political than technical, priorizes the strategies that assure the integration of the environmental, social, economic and institutional aspects into the planning process, in private or public organizations. In this context, this work aims to establish the concept basis of the Strategic Environmental Evaluation as a tool for land planning and managing. The methodology procedures used here lie in the literature review concerning the SEA, analyzing how this tool can be introduced as an alternative for sustainable development. Although the SEA is a tool that introduces the sustainable development theme as a guiding principle of planning, it is seldom used by managers and decision makers, locally and nationally

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The Dansgaard-Oeschger oscillations and Heinrich events described in North Atlantic sediments and Greenland ice are expressed in the climate of the tropics, for example, as documented in Arabian Sea sediments. Given the strength of this teleconnection, we seek to reconstruct its range of environmental impacts. We present geochemical and sedimentological data from core SO130-289KL from the Indus submarine slope spanning the last ~ 80 kyr. Elemental and grain size analyses consistently indicate that interstadials are characterized by an increased contribution of fluvial suspension from the Indus River. In contrast, stadials are characterized by an increased contribution of aeolian dust from the Arabian Peninsula. Decadal-scale shifts at climate transitions, such as onsets of interstadials, were coeval with changes in productivity-related proxies. Heinrich events stand out as especially dry and dusty events, indicating a dramatically weakened Indian summer monsoon, potentially increased winter monsoon circulation, and increased aridity on the Arabian Peninsula. This finding is consistent with other paleoclimate evidence for continental aridity in the northern tropics during these events. Our results strengthen the evidence that circum-North Atlantic temperature variations translate to hydrological shifts in the tropics, with major impacts on regional environmental conditions such as rainfall, river discharge, aeolian dust transport, and ocean margin anoxia.

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Human-induced habitat destruction, overexploitation, introduction of alien species and climate change are causing species to go extinct at unprecedented rates, from local to global scales. There are growing concerns that these kinds of disturbances alter important functions of ecosystems. Our current understanding is that key parameters of a community (e.g. its functional diversity, species composition, and presence/absence of vulnerable species) reflect an ecological network's ability to resist or rebound from change in response to pressures and disturbances, such as species loss. If the food web structure is relatively simple, we can analyse the roles of different species interactions in determining how environmental impacts translate into species loss. However, when ecosystems harbour species-rich communities, as is the case in most natural systems, then the complex network of ecological interactions makes it a far more challenging task to perceive how species' functional roles influence the consequences of species loss. One approach to deal with such complexity is to focus on the functional traits of species in order to identify their respective roles: for instance, large species seem to be more susceptible to extinction than smaller species. Here, we introduce and analyse the marine food web from the high Antarctic Weddell Sea Shelf to illustrate the role of species traits in relation to network robustness of this complex food web. Our approach was threefold: firstly, we applied a new classification system to all species, grouping them by traits other than body size; secondly, we tested the relationship between body size and food web parameters within and across these groups and finally, we calculated food web robustness. We addressed questions regarding (i) patterns of species functional/trophic roles, (ii) relationships between species functional roles and body size and (iii) the role of species body size in terms of network robustness. Our results show that when analyzing relationships between trophic structure, body size and network structure, the diversity of predatory species types needs to be considered in future studies.

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