826 resultados para Ecological and environmental anthropology


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Quercus robur L. (pedunculate oak) and Quercus petraea (Matt.) Liebl. (sessile oak) are two European oak species of great economic and ecological importance. Even though both oaks have wide ecological amplitudes of suitable growing conditions, forests dominated by oaks often fail to regenerate naturally. The regeneration performance of both oak species is assumed to be subject to a variety of variables that interact with one another in complex ways. The novel approach of this research was to study the effect of many ecological variables on the regeneration performance of both oak species together and identify key variables and interactions for different development stages of the oak regeneration on a large scale in the field. For this purpose, overstory and regeneration inventories were conducted in oak dominated forests throughout southern Germany and paired with data on browsing, soil, and light availability. The study was able to verify the assumption that the occurrence of oak regeneration depends on a set of variables and their interactions. Specifically, combinations of site and stand specific variables such as light availability, soil pH and iron content on the one hand, and basal area and species composition of the overstory on the other hand. Also browsing pressure was related to oak abundance. The results also show that the importance of variables and their combinations differs among the development stages of the regeneration. Light availability becomes more important during later development stages, whereas the number of oaks in the overstory is important during early development stages. We conclude that successful natural oak regeneration is more likely to be achieved on sites with lower fertility and requires constantly controlling overstory density. Initially sufficient mature oaks in the overstory should be ensured. In later stages, overstory density should be reduced continuously to meet the increasing light demand of oak seedlings and saplings.

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Ecological succession provides a widely accepted description of seasonal changes in phytoplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes) and larger (i.e. macroplankton) organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish larvae, for which no consistent data were available). Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche) weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model) characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally.

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Background: Understanding and influencing the determinants of physical activity is an important public health challenge. We used prospective data to examine the influence of individual, social, and environmental factors on physical activity behaviour, using regular running as the behavioural model. Methods: Over 500 middle-aged women completed two consecutive questionnaires in 2000 and 2002. Logistic regression analyses were used to examine factors predicting adoption of and regression from regular leisure-time running during the follow-up. Results: Women who frequently used behavioural change skills were more likely to adopt regular running (OR=4.0, CI=1.7-9.5). There was an interaction between the enjoyment of running and family support: those who rated enjoyment of running high and reported high family support were less likely to adopt running (OR= 0.2, CI = 0.1-0.5). Women who reported infrequent use of motives were more likely (OR = 3.3, CI = 1.6-6.9) to regress from regular running. There was an interaction between perceived health and the neighbourhood environment: those who perceived themselves to be in poor health and had an unattractive neighbourhood were more likely (OR = 2.7, CI = 0.9-8.3) to regress from regular running. Conclusions: Behavioural skills and enjoyment may be of particular importance for the adoption of regular activity; social support and an aesthetically attractive neighbourhood are likely to have a key role in encouraging maintenance. (c) 2004 Elsevier Ltd. All rights reserved.

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Whilst traditional optimisation techniques based on mathematical programming techniques are in common use, they suffer from their inability to explore the complexity of decision problems addressed using agricultural system models. In these models, the full decision space is usually very large while the solution space is characterized by many local optima. Methods to search such large decision spaces rely on effective sampling of the problem domain. Nevertheless, problem reduction based on insight into agronomic relations and farming practice is necessary to safeguard computational feasibility. Here, we present a global search approach based on an Evolutionary Algorithm (EA). We introduce a multi-objective evaluation technique within this EA framework, linking the optimisation procedure to the APSIM cropping systems model. The approach addresses the issue of system management when faced with a trade-off between economic and ecological consequences.

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In recent years there has been growing concern about the emission trade balances of countries. This is due to the fact that countries with an open economy are active players in international trade. Trade is not only a major factor in forging a country’s economic structure, but contributes to the movement of embodied emissions beyond country borders. This issue is especially relevant from the carbon accounting policy and domestic production perspective, as it is known that the production-based principle is employed in the Kyoto agreement. The research described herein was designed to reveal the interdependence of countries on international trade and the corresponding embodied emissions both on national and on sectoral level and to illustrate the significance of the consumption-based emission accounting. It is presented here to what extent a consumption-based accounting would change the present system based on production-based accounting and allocation. The relationship of CO2 emission embodied in exports and embodied in imports is analysed here. International trade can blur the responsibility for the ecological effects of production and consumption and it can lengthen the link between consumption and its consequences. Input-output models are used in the methodology as they provide an appropriate framework for climate change accounting. The analysis comprises an international comparative study of four European countries (Germany, the United Kingdom, the Netherlands, and Hungary) with extended trading activities and carbon emissions. Moving from a production-based approach in climate policy to a consumption-based principle and allocation approach would help to increase the efficiency of emission reductions and would force countries to rethink their trading activities in order to decrease the environmental load of production activities. The results of this study show that it is important to distinguish between the two emission accounting approaches, both on the global and the local level.

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Egyre többen ismerik fel, hogy az élelmiszer-fogyasztás egészségügyi és környezeti hatása is jelentős. A különböző életstílusú társadalmi csoportok fogyasztási szerkezete eltérő lehet. Jelen tanulmány ezerfős, országos reprezentatív minta alapján vizsgálja az élelmiszer-fogyasztási szerkezet eltéréseit a nemek és különböző iskolázottságú fogyasztók körében. Jellemző fogyasztási klasztereket tár fel a fogyasztás szerkezete alapján. A fogyasztás szerkezeti és mennyiségi értékein túlmenően az ökológiai lábnyom indikátorával a fogyasztás környezetterhelését is számszerűsíti. _____ Concern about both health and environmental impacts of food consumption is increasing. Social groups with various lifestyles can have different food consumption structure. The present study analyses the differences in the food consumption structure among genders and educational groups based on a national, representative survey of 1000 adults. Food consumption clusters are identified based on food consumption structure. Beyond the analysis of food consumption and its structure, its environmental impact is quantified by the ecological footprint indicator.

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The coastal districts, as an intersection of two perfectly different ecosystems of dry land and sea, is one of the most complicated and the richest natural system on earth. Considering these areas are constantly exposed to aggregation of water pollutants and also consequence resulting from construction and development activities, they are very vulnerable. Therefore, "sensitive Coastal areas" has become a common word in the related subjects to marine environment recently. The said title relates to the areas of the coastal lines which are vulnerable to the natural condition or human actions because of ecological, social, economic, educational and research importance, also they need particular supports. The southern coasts of Caspian Sea, In Iran prominent samples are of these sensitive areas which their environment are exposed to demolition and destruction intensely, due to increasing and uncontrolled development. The first stage of protecting and managing the coastal areas is identifying sensitive Coastal areas and broadening the Coasts. In this survey, we attempted to examine a definite area in the southern coasts of Caspian Sea. In Iran, by profiting from the world experiences and concluded researches in Iran especially the concluded studies by marine environment office and the Environment protection organization on the subject of determination criteria of the sensitive ecological districts. For this purpose (In Gilan Province) Boujagh national park district which is located in the mouth of sefidroud river and also is possessed of the special ecological and environmental features and distinctions. In this survey, first they said district is divided proportionally on the basis of using a grid system in order to identify the sensitive ecological districts and broaden the coast, and then the desired indices have been determined and scored by numeral valuation method in each unit and then analysis has been done by using of the geography information system (GIS) and final has estimated economic valuation of sensitive ecological areas that is presented in this essay.

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Understanding the ecology of migratory birds during the non-breeding season is necessary for ensuring their conservation. Using satellite telemetry data we describe winter ranging behaviour and movements of pallid harriers Circus macrourus that bred in Kazakhstan. We developed an ecological niche model for the species in Africa, to identify the most suitable wintering areas for pallid harriers and the importance of habitat in determining the location of those areas. We also assessed how well represented suitable areas are in the network of protected areas. Individual harriers showed relatively high fidelity to wintering areas but with potential for interannual changes. The ecological niche model highlighted the importance of open habitats with natural vegetation. Most suitable areas for the species were located in eastern Africa. Suitable areas had a patchy distribution but were relatively well included in the network of protected areas. The preferential use of habitats with natural vegetation by wintering pallid harriers and the patchiness of the most suitable areas highlight the harrier's vulnerability to land-use changes and the associated loss of natural vegetation in Africa. Conservation of harriers could be enhanced by preserving natural grasslands within protected areas and improving habitat management in the human-influenced portions of the species’ core wintering areas.

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Dairy cattle farms have a well-known environmental impact that affects all ecological compartments: air, soil, water and biosphere [1]. Dairy cattle farming are a significant source of anthropogenic gases from enteric fermentation, manure storage and land application, mainly ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). The emission of such gases represents not only an environmental problem but also leads to energy and nitrogen (N) losses in ruminant production systems [2-5]. Several efforts are required on the development of new technologies and strategies that mitigate gaseous emissions, N losses and improve the efficiency of the energy and N cycles [6, 7]. In the Northwest of Portugal, dairy cattle production has a major impact on the economy, with strong repercussions at national scale. Therefore, our Ph.D. thesis project aims to: a) Study natural supplements as additives in the dairy cattle diet towards a decrease in GHG emissions from feeding operations; b) Compare commercial dairy cattle diets with and without additives on gaseous emissions from manure deposited in a simulated concrete floor; c) Assess the concentrations and emissions of NH3 and greenhouse gases from commercial dairy cattle facilities; d) Evaluate the effects of different additives on lowering gaseous emissions from dairy cattle excreta, using a laboratory system simulating a dairy house concrete floor.