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151.
Silvestre García de Jalón Ana Iglesias Ruth Cunningham Juan I. Pérez Díaz 《Regional Environmental Change》2014,14(3):1229-1242
Agricultural water management needs to evolve in view of increased water scarcity, especially when farming and natural protected areas are closely linked. In the study site of Doñana (southern Spain), water is shared by rice producers and a world heritage biodiversity ecosystem. Our aim is to contribute to defining adaptation strategies that may build resilience to increasing water scarcity and minimize water conflicts among agricultural and natural systems. The analytical framework links a participatory process with quantitative methods to prioritize the adaptation options. Bottom-up proposed adaptation measures are evaluated by a multi-criteria analysis (MCA) that includes both socioeconomic criteria and criteria of the ecosystem services affected by the adaptation options. Criteria weights are estimated by three different methods—analytic hierarchy process, Likert scale and equal weights—that are then compared. Finally, scores from an MCA are input into an optimization model used to determine the optimal land-use distribution in order to maximize utility and land-use diversification according to different scenarios of funds and water availability. While our results show a spectrum of perceptions of priorities among stakeholders, there is one overriding theme that is to define a way to restore part of the rice fields to natural wetlands. These results hold true under the current climate scenario and even more so under an increased water scarcity scenario. 相似文献
152.
Experimental Characterization of Atmospheric Diffusion in Complex Terrain with Land-Sea Interactions
M. M. Mill´n E. Otamendi L. A. Alonso I. Ureta 《Journal of the Air & Waste Management Association (1995)》2013,63(7):807-811
The body of information presented in this paper is directed to scientists working in atmospheric dispersion research and model development. Two years of field measurements in the coastal area of Bilbao in northern Spain show that the diffusion behavior in this complex terrain can be classified into several well defined patterns, which correspond to certain meteorological conditions. The approach taken has been the systematic use of SO2 remote sensors (COSPEC) and ground level monitors in moving platforms which are used to follow and document the flow of the air mass. Results to date show that complex reentry cycles can occur and that synoptically different flows may be indistinguishable by wind sensors at ground level (affected by channeling), and yet result in totally different observed pollution levels by a fixed monitoring network (affected by topographical effects). These results are being used to parameterize the cause-effect relationships and guide the modeling efforts in this area of complex terrain. 相似文献
153.
Aron D. Jazcilevich Agustín R. García L. Gerardo Ruiz-Suárez Xóchitl Cruz-Nuñez Javier C. Delgado Carlos Tellez 《Journal of the Air & Waste Management Association (1995)》2013,63(3):366-378
Abstract Using an air quality model, two future urban scenarios induced by the construction of the new international airport for Mexico City are compared at a regional level. The air quality model couples the meteorology model MM5 and state-of-the-art photochemistry. The air quality comparison is made using metrics for the criterion gases selected for the study. From the two urban scenarios compared, the option for Tizayuca is moderately better than the option for Texcoco, because relative reductions in O3 and other photochemical pollutants are achieved over highly populated areas. Regardless of the site, the air quality for the central region of Mexico in the future will deteriorate. In the region of central Mexico, SO2 and NO2 will become important pollutants. 相似文献
154.
Baeza A Vallejo I Guillén J Salas A Corbacho JA 《Journal of environmental radioactivity》2011,102(3):311-315
Adequate radioprotection of the environment requires the identification of biomonitors sensitive to the variation of its radionuclide content. Due to the chemical similarities between calcium and strontium, calcified tissues of mammals are considered to be good 90Sr biomonitors. This work considered Cervus elaphus antlers which, being shed annually, can give information about the importance of radiostrontium contamination in an ecosystem in the time period required for the growth of the antler. The samples were collected at various points of W and SW Spain. The mean value of their 90Sr content was (70 ± 43 (S.D.)) Bq/kg d.w., range (16-218) Bq/kg d.w., and the radionuclide was evenly distributed in the different parts of the antler. There was a good correlation between the antlers’ 90Sr content and the 90Sr deposited in the soil. The antlers’ content of 226Ra (from the natural uranium series) and the contents of some stable elements (Ca, Mg, Sr, and K) were also determined. The values for these stable elements were practically constant in the analyzed samples, and the concentrations measured decreased in the following order:Ca » Mg > K > Sr » 90Sr > 226Ra 相似文献
155.
Ecosystem services and hydroelectricity in Central America: modelling service flows with fuzzy logic and expert knowledge 总被引:1,自引:0,他引:1
Bruno Locatelli Pablo Imbach Raffaele Vignola Marc J. Metzger Efraín José Leguía Hidalgo 《Regional Environmental Change》2011,11(2):393-404
Because ecosystem services are generally not produced and used in the same place, their assessment should consider the flows
of services from ecosystems to users. These flows depend on the characteristics and spatial distribution of ecosystems and
users, the spatial relationships between them, and the presence of filters or barriers between ecosystems and users. The objective
of this paper is to map the ecosystem services provided to the Costa Rican and Nicaraguan hydroelectric sectors, which are
crucial sectors for national sustainable development and depend directly on hydrological ecosystem services. The paper presents
an approach for modelling the flows of multiple services from diverse ecosystems to diverse users through different kinds
of filters in a landscape. The approach uses expert knowledge and fuzzy numbers to handle uncertainties. The analyses for
Costa Rica and Nicaragua show how the approach helps identify priority areas for the conservation and restoration of forests
for the services they provide to the hydroelectric sector. As such, it is a useful tool for defining spatially targeted policies
for the conservation of ecosystem services and for involving the users of ecosystem services in ecosystem management. 相似文献
156.
There is the need to integrate existing toxicity data in a coherent framework for extending their domain of applicability as well as their extrapolation potential. This integration would also reduce time and cost-consuming aspects of these tests and reduce animal usage. In this work, based on data extracted from literature, we have assessed the advantages that a dynamic biology-toxicant fate coupled model for Daphnia magna could provide when assessing toxicity data, in particular, the possibility to obtain from short-term (acute) toxicity test long-term (chronic) toxicity values taking into account the inherent variability of D. magna populations and the multiple sources of data. The results show that this approach overcomes some of the limitations of existing toxicity tests and that the prediction errors are considerably reduced when compared with the factor from 2 to 5 obtained using acute-to-chronic ratios. 相似文献
157.
A study has been made of the effect a reactive barrier made of pine (softwood) or oak (hardwood) wood intercalated in a sandy soil column has on the retention of linuron, alachlor and metalaxyl (pesticides with contrasting physicochemical characteristics). The leaching of pesticides has been carried out under a saturated flow regime and breakthrough curves (BTCs) have been obtained at flow rates of 1 mL min−1 (all pesticides) and 3 mL min−1 (linuron). The cumulative curves in the unmodified soil indicate a leaching of pesticides >80% of the total amount of compound added. After barrier intercalation, linuron leaching decreases significantly and a modification of the leaching kinetics of alachlor and metalaxyl has been observed. The theoretical R factors increased ∼2.6-3.3, 1.2-1.6-fold, and 1.4-1.7-fold and the concentration of the maximum peak decreased ∼6-12-fold, 2-4-fold and 1.2-2-fold for linuron, alachlor and metalaxyl, respectively. When considering the three pesticides, significant correlations have been found between the theoretical retardation factor (R) and the pore volume corresponding to the maximum peaks of the BTCs (r = 0.77; p < 0.05) or the total volume leached (r = −0.78; p < 0.05). The results reveal the efficacy of reactive wood barriers to decrease the leaching of pesticides from point sources of pollution depends on the type of wood, the hydrophobicity of the pesticide and the adopted water flow rate. Pine was more effective than oak in decreasing the leaching of hydrophobic pesticide linuron or in decreasing the maximum peak concentration of the less hydrophobic pesticides in soils. Efficacy of these wood barriers was limited for the least hydrophobic pesticide metalaxyl. 相似文献
158.
Ochoa-Hueso R Allen EB Branquinho C Cruz C Dias T Fenn ME Manrique E Pérez-Corona ME Sheppard LJ Stock WD 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2265-2279
We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling. 相似文献
159.
Novais SC Gomes SI Gravato C Guilhermino L De Coen W Soares AM Amorim MJ 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1836-1843
To better understand chemical modes of action, emphasis has been given to stress responses at lower levels of biological organization. Cholinesterases and antioxidant defenses are among the most used biomarkers due to their crucial role in the neurocholinergic transmission and in cell homeostasis preventing DNA damage, enzymatic inactivation and lipid peroxidation. The main goal of this study was to investigate the effects of zinc and cadmium on survival and reproduction of E. albidus and to assess metals oxidative stress potential and neurotoxic effects at concentrations that affected reproduction. Both metals affected the enchytraeids’ survival and reproduction and induced significant changes in the antioxidant defenses as well as increased lipid peroxidation, indicating oxidative damage. This study demonstrates that determining effects at different levels of biological organization can give better information on the physiological responses of enchytraeids in metal contamination events and further unravel the mechanistic processes dealing with metal stress. 相似文献
160.
Real C Ángel Fernández J Aboal JR Carballeira A 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2797-2800
Multivariate analysis of environmental data sets requires the absence of missing values or their substitution by small values. However, if the data is transformed logarithmically prior to the analysis, this solution cannot be applied because the logarithm of a small value might become an outlier. Several methods for substituting the missing values can be found in the literature although none of them guarantees that no distortion of the structure of the data set is produced. We propose a method for the assessment of these distortions which can be used for deciding whether to retain or not the samples or variables containing missing values and for the investigation of the performance of different substitution techniques. The method analyzes the structure of the distances among samples using Mantel tests. We present an application of the method to PCDD/F data measured in samples of terrestrial moss as part of a biomonitoring study. 相似文献