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731.
Nitrate and pesticide contamination of surface and groundwater has become a major problem in intensive farming regions in Europe, with nitrate concentrations reaching values above the standard defined in 2000 by the European Water Framework Directive. In the Seine basin, a major issue is the closure and abandonment of drinking-water wells, which force water managers and drinking-water producers to explore solutions for water resource protection. Organic farming has appeared as a credible alternative to conventional farming, and this study explores the potential of organic farming to reconcile agricultural production and water quality. On the basis of agricultural statistics, survey questionnaires and experimental data, the nitrogen soil surface balance (N-SSB) has been established at the scale of a small 104-km2 catchment (The Orgeval sub-basin), representative of the intensive cash crop farming in the Seine basin. The N-surplus for arable land in specialized organic cash crop systems has been found to be half that of current conventional systems (15 kg N ha−1 yr−1 versus 30 kg N ha−1 yr−1, respectively). The N-yield in organic systems is 21% lower than in conventional systems, but total fertilization (mostly symbiotic N fixation) is also 26% lower. Whereas 2–3 years of forage legume (e.g., alfalfa) as a starter crop of the typical 7- to 10-year diversified rotation builds up N soil fertility and helps prevent weeds without pesticides, the existence of an outlet for this fodder production is a limiting factor for the economic sustainability and the environmental benefits of these farming systems. Therefore, we explored the possibility of a reconnection of livestock and crop farming systems in the Orgeval catchment, a traditional dairy farming and Brie cheese production region. We calculated the N-SSB for this type of a reconnected livestock and cropping system and found a value very close to the specialized organic cash crop system with full utilization of fodder production, leading to profitable animal production, essentially as milk in this farm design. This reconnected system is compared with the estimated situation in 1955 before separation of plant and livestock production. Furthermore, the N-SSB values were converted into infiltrating sub-root concentrations and used as a boundary condition to a biogeochemical model. Organic cropping and organic reconnected livestock cropping systems result in a 50% reduction of surface water nitrate concentrations, a surface water quality 20% better than that reconstructed for 1955, with an overall higher protein production.  相似文献   
732.
Far-from-equillibrium oscillating chemical reactions are among the simplest systems showing complex behaviors and emergent properties. This class of reactions is often employed to mimic and understand the mechanisms of a great variety of biological processes. In this context, pattern formation due to the coupling between reaction and transport phenomena represent an active and promising research area. In this paper, we present results coming from experiments where we tried to blend the structural properties of self-assembled matrixes (sodium dodecyl sulphate micelles and phospholipid bilayers) together with the evolutive peculiarities of the Belousov–Zhabotinsky reaction. A series of interesting dynamical behaviors, like spatio-temporal chaos, stationary patterns and segmented waves, were found in reaction–diffusion and reaction–diffusion–convection experiments.  相似文献   
733.
Water quality modelling is an effective tool to investigate, describe and predict the ecological state of an aquatic ecosystem. Various environmental variables may simultaneously affect water quality. Appropriate selection of a limited number of key-variables facilitates cost-effective management of water resources. This paper aims to determine (and analyse the effect of) the major environmental variables predicting ecological water quality through the application of fuzzy models. In this study, a fuzzy logic methodology, previously applied to predict species distributions, was extended to model environmental effects on a whole community. In a second step, the developed models were applied in a more general water management context to support decision and policy making. A hill-climbing optimisation algorithm was applied to relate ecological water quality and environmental variables to the community indicator. The optimal model was selected based on the predictive performance (Cohen’s Kappa), ecological relevance and model’s interpretability. Moreover, a sensitivity analysis was performed as an extra element to analyse and evaluate the optimal model. The optimal model included the variables land use, chlorophyll and flow velocity. The variable selection method and sensitivity analysis indicated that land use influences ecological water quality the most and that it affects the effect of other variables on water quality to a high extent. The model outcome can support spatial planning related to land use in river basins and policy making related to flows and water quality standards. Fuzzy models are transparent to a wide range of users and therefore may stimulate communication between modellers, river managers, policy makers and stakeholders.  相似文献   
734.
How does the resilience concept of nested relationships (panarchy) contribute to sustainability science and policy? Resilience at a particular level of organization, the community level in our case, is influenced by internal processes at that level. But it is also impacted by actions at lower levels of organization (individuals, households), and by drivers of change originating at higher levels (national level policies, globalized market forces). We focus on community level social-ecological systems, looking upwards and downwards from there. Our objective is to explore the connections of the community to other levels, the ways in which community resilience is impacted, and the implications of this for sustainability. Conventional disciplines specialize at different levels, a barrier to investigating multi-level interactions. Use of the panarchy concept helps contribute to the interdisciplinary understanding of resilience at the community (and other levels) by drawing attention to cross-scale relationships. From the effect of individual leadership to the implication of pandemics that move swiftly across levels, examples illustrate a diversity of ways in which community resilience is shaped in a multi-level world.  相似文献   
735.
On the basis of the GISS prognostic climatic model, landscape-ecological scenarios concerning the immediate future of the region are considered in the forms of cartographic and analytical models. These scenarios predict a growing thermoarid bioclimatic trend accompanied by a general northward displacement of zonal boundaries, with corresponding acceleration of the biological cycle and increase in the productivity of boreal forests.  相似文献   
736.
《Environmental Hazards》2013,12(4):266-282
An exploratory study is conducted to assess the resilience of Infanta through an analysis of its ecosystems from ecological, physical, economic, social and institutional perspectives. Recognizing the strong interdependencies of ecological, physical, economic, social and institutional dimensions in ecosystems and that community-level perceptions can shape adaptation actions, a survey is conducted in 36 village councils in Infanta, Quezon, Philippines utilizing a questionnaire covering 5 dimensions, 25 parameters and 125 measures selected based on the local context of Infanta to gain an understanding of the level of resilience in mountain, riverine, urban, agricultural plain, estuarine and coastal ecosystems. Results show that overall resilience levels of ecosystems lie between 3.08 (medium resilience) and 3.26 (high resilience) on a scale of 1–5. However, resilience scores in the five dimensions vary from 2.57 (low resilience) to 3.51 (high resilience). On the whole, overall resilience levels in the 36 villages exhibit high levels in the social dimension and low levels in the economic dimension. By assessing the resilience of ecosystems as attempted in this study, a baseline is determined where entry points for adaptation actions that are responsive to prevailing ecosystem conditions can be identified, positive and negative factors addressed and gaps and opportunities acted upon to enhance the resilience of Infanta's ecosystems.  相似文献   
737.
This paper describes the application of a continuous daily water balance model called SWAT (Soil and Water Assessment Tool) for the conterminous U.S. The local water balance is represented by four control volumes; (1) snow, (2) soil profile, (3) shallow aquifer, and (4) deep aquifer. The components of the water balance are simulated using “storage” models and readily available input parameters. All the required databases (soils, landuse, and topography) were assembled for the conterminous U.S. at 1:250,000 scale. A GIS interface was utilized to automate the assembly of the model input files from map layers and relational databases. The hydrologic balance for each soil association polygon (78,863 nationwide) was simulated without calibration for 20 years using dominant soil and land use properties. The model was validated by comparing simulated average annual runoff with long term average annual runoff from USGS stream gage records. Results indicate over 45 percent of the modeled U.S. are within 50 mm of measured, and 18 percent are within 10 mm without calibration. The model tended to under predict runoff in mountain areas due to lack of climate stations at high elevations. Given the limitations of the study, (i.e., spatial resolution of the data bases and model simplicity), the results show that the large scale hydrologic balance can be realistically simulated using a continuous water balance model.  相似文献   
738.
The oil and gas industry in Norway has taken into use and is developing ICT-based work processes to improve efficiency and safety. Protection of information resources and technology; ensuring safe and secure processing of information; and ensuring reliable and safe flow of information is essential for both production and protection in such ICT-intensive organizations. Information systems security (IS) thus matters for major accident prevention. In the ICT-based work processes in the oil and gas industry new challenges for IS security occur related to: increased need for availability and integrity of information; merge of process safety systems and ICT-systems; manual use of information resources; and flow of information between distributed actors. These challenges imply new requirements for IS management: More focus on availability and integrity as protection principles; resilience-based approaches as a supplement to formal management approaches; validation of information flows; and integration of loss prevention approaches.  相似文献   
739.
In this paper we examine the effect of Gross Domestic Product (GDP) on the level of fish intake in China in comparison with the rest of the world. We also analyse the origin and destination of China’s seafood products in order to understand the main patterns during the last decades. The results show that in the 1961–2011 period the rate of growth of the GDP in China doubled that of other developing regions, while the daily fish intake of China increased fourfold, making China the largest fish consumer in the world. Given the size and scale of China’s role in production, consumption, and global transformation of seafood markets, China is shaping a new era of industrialization in the history of the fishing industry.  相似文献   
740.
This paper examines some of the social processes associated with disaster conditions. Utilising an asset‐based perspective of community capacity, it focuses on four types of normative systems to interpret the ability of communities to manage disasters through market‐, bureaucratic‐, associative‐, and communal‐based norms. Drawing on experience of a wildfire in the Crowsnest Pass region of southwest Alberta, Canada, in 2003, the tensions and compatibilities among these normative systems are evaluated through interviews with 30 community leaders. The results confirm the contributions of all types of social capital to resiliency, the necessity for rapid use of place‐based knowledge, and the importance of communication among all types and levels of agents. In addition, they point to the value of identifying and managing potential conflicts among the normative systems as a means to maximising their contributions. The integration of local networks and groups into the more general disaster response minimised the impacts on health and property.  相似文献   
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