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11.
This paper explores the development towards sustainability management systems (SMSs) in three Swedish local authorities. Many local authorities have extensive experience in using standardised Environmental Management Systems (EMSs). Recently EMSs have extended their reach by widening the scope of the systems including other dimensions of sustainable development. Case studies have been performed in three of the most EMS-experienced local authorities in Sweden. These authorities have extended their EMSs into a sustainability management approach in different ways. This paper discusses the development, possible contributions, and constraints with this development. Expanding EMSs into SMSs can be seen as a learning process in which a larger systems perspective leads to increased awareness that the management system becomes limited by only managing environmental issues. Expanding the EMSs into SMSs may lead to a more complete view of the organisation's total impact on nature and society, and issues that need to be managed.  相似文献   
12.
引言 北极已成为对当前气候波动和预计的全球变暖增强的影响进行评估的重要地区.原因有以下几个方面:①在过去几十年中北极经历了大幅度的变暖过程(温度平均升高3℃,而在许多地区温度升高了4~5℃);②气候预测表明气候呈现持续变暖趋势,在2080年之前年平均气温升高4~5℃;③近期的气候变暖正在影响北极的环境和经济,这些影响还会加大,并对生活方式、文化及生态系统造成影响;④北极的变化可能会影响到地球上的其它地区.  相似文献   
13.
北极生态系统的生物和物理过程会在不同的时间、空间尺度上对地球生态系统产生反馈作用,并与之相互影响.气候变化对北极地区的影响及其对全球气候系统的反馈主要存在着四种潜在机制反照率改变、生态系统对温室气体的排放或吸收、甲烷类温室气体的排放、影响海洋暖流淡水量的增长.这些反馈机制在某种程度上是由生态系统的分布和特征,尤其是大规模植被区域变化来控制的.通过少量全年的CO2通量测量表明,目前在地理分布上碳源区要比碳汇区要多.根据目前现有的关于CH4排放源地信息表明,景观规模上的CH4排放量对北极地区的温室效应平衡至关重要.北极地区的能量和水量平衡在变化的气候下,也是一个很重要的反馈机制.植被密度以及分布范围的增加会导致反射率的下降,因而会使地表吸收更多的能量.其效果可能会抵消由于极地沙漠地带向极地苔原带的的转化,或极地苔原带向极地森林带的转化,而造成的植被总净初级生产力碳沉降能力的提高而引起的负反馈.永久冻土带的退化对示踪气体动力学有着很复杂的影响.在不连续的永久冻土带地区,升温将会导致其完全消失.依赖于当地水文条件,温室气体排放可能由于气候环境变的干燥或湿润而使得其通量有所变化.总的来说,影响反馈的各种过程复杂的相互作用,以及这些过程随着时间地点的变化,加之数据的缺乏,又会在陆地生态系统气候变化对气候系统产生反馈作用的净效应估计上,产生许多的不确定性,这种不确定性将会影响到一些反馈的大小和方向.  相似文献   
14.
Summary Variations in the begging behaviour of the nestlings of altricial birds can provide the parents with information about the nestlings' nutritional needs and thus influence the parental feeding rate. In a series of four experiments, the stimulus situation encountered by great tits on their feeding visits to the brood was manipulated to explore its effect on feeding rate.A higher feeding rate was observed under the following conditions: (1) after a period of food deprivation, as compared with both normal conditions and satiation through artificial feeding; (2) in periods when recorded begging calls were played during feeding visits, as compared with control periods; (3) after temporary removal from the nest of heavier, as compared with lighter, siblings. The lighter nestlings in the brood benefitted more —in terms of gain in weight — from the increase in parental feeding rate following the playing of begging calls than did the heavier nestlings. Differences in weight spread within broods did not affect the amount of food the parents brought.We conclude that parental feeding rate is affected not simply by the begging of the hungriest nestling, but rather by the behaviour of all the nestlings in the brood, which makes possible an adjustment of the feeding rate to the average hunger level of the brood. The effects of hatching asynchrony and sibling competition on parental feeding rate are discussed.  相似文献   
15.
Historically, the function of Arctic ecosystems in terms of cycles of nutrients and carbon has led to low levels of primary production and exchanges of energy, water and greenhouse gases have led to low local and regional cooling. Sequestration of carbon from atmospheric CO2, in extensive, cold organic soils and the high albedo from low, snow-covered vegetation have had impacts on regional climate. However, many aspects of the functioning of Arctic ecosystems are sensitive to changes in climate and its impacts on biodiversity. The current Arctic climate results in slow rates of organic matter decomposition. Arctic ecosystems therefore tend to accumulate organic matter and elements despite low inputs. As a result, soil-available elements like nitrogen and phosphorus are key limitations to increases in carbon fixation and further biomass and organic matter accumulation. Climate warming is expected to increase carbon and element turnover, particularly in soils, which may lead to initial losses of elements but eventual, slow recovery. Individual species and species diversity have clear impacts on element inputs and retention in Arctic ecosystems. Effects of increased CO2 and UV-B on whole ecosystems, on the other hand, are likely to be small although effects on plant tissue chemisty, decomposition and nitrogen fixation may become important in the long-term. Cycling of carbon in trace gas form is mainly as CO2 and CH4. Most carbon loss is in the form of CO2, produced by both plants and soil biota. Carbon emissions as methane from wet and moist tundra ecosystems are about 5% of emissions as CO2 and are responsive to warming in the absence of any other changes. Winter processes and vegetation type also affect CH4 emissions as well as exchanges of energy between biosphere and atmosphere. Arctic ecosystems exhibit the largest seasonal changes in energy exchange of any terrestrial ecosystem because of the large changes in albedo from late winter, when snow reflects most incoming radiation, to summer when the ecosystem absorbs most incoming radiation. Vegetation profoundly influences the water and energy exchange of Arctic ecosystems. Albedo during the period of snow cover declines from tundra to forest tundra to deciduous forest to evergreen forest. Shrubs and trees increase snow depth which in turn increases winter soil temperatures. Future changes in vegetation driven by climate change are therefore, very likely to profoundly alter regional climate.  相似文献   
16.
引言 人们普遍认为,全球气候变暖在北极将进一步放大,由于平流层臭氧修复的可能延误,紫外线B(UV-B)辐射可能继续增加,北极环境及其居民可能特别易受这类环境变化的影响.上述共识促进了对气候变化影响的国际评估工作.北极气候影响评估(ACIA)是一项为时4年的研究,结果出版了一篇重要的科研报告[1]并产生了其他的成果.在本文以及本期Ambio专刊下面的文章中,我们提供了报告中针对北极陆地生态系统(从树线群落交错带到极地荒漠)的部分研究成果.  相似文献   
17.
DNA damage in the form of cyclobutane pyrimidine dimers(CPDs) and (6-4) photopreducts(6-4PPs) induced by UV-B radiation in Arabidopsis thaliana at different temperatures was investigated using ELISA with specific monoclonal antibodies. CPDs and 6-4PPs increased during 3 h UV-B exposure, but further exposure led to decreases. Contrary to the commonly accepted view that DNA damage induced by UV-B radiation is temperature-independent because of its photochemical nature, we found UV-B-induction of CPDs and 6-4PPs in Arabidopsis to be slower at a low than at a high temperature. Photorepair of CPDs at 24℃ was much faster than that at 0℃ and 12℃,with 50% CPDs removal during 1 h exposure to white light. Photorepair of 6-4PPs at 12℃ was very slow as compared with that at 24℃,and almost no removal of 6-4PPs was detected after 4 h exposure to white light at 0℃. There was evidence to suggest that temperaturedependent DNA damage and photorepair could have important ecological implications.  相似文献   
18.
Participation in decision-making has successively developed into a guiding principle at both EU and national level. However, diverse perspectives exist on what the role of different interests in participative processes should be, and the legal rules regarding participation varies between different sectors; from clearly defined to virtually non-existent requirements. This may have adverse effects on the legitimacy of decisions and decision-making. This paper reviews the role of participation in the planning process in relation to natural resource development in Sweden, as guided by EU and international law. Based on the notion of effective participation, the study illustrates the potential clashes that may result from different conceptions of participation, for instance, at various levels of governance, as well as from disparate principles for implementation in different sectors.  相似文献   
19.
This paper estimates the costs of producing biological diversity on Swedish permanent grasslands. A simple model is introduced where biodiversity on pastures is produced using grazing animals. On the pastures, the grazing animals create a sufficient grazing pressure to lead to an environment that suits many rare and red-listed species. Two types of pastures are investigated: semi-natural and cultivated. Biological diversity produced on a pasture is estimated by combining a biodiversity indicator, which measures the quality of the land, with the size of the pasture. Biodiversity is, in this context, a quantitative measure where a given quantity can be produced either by small area with high quality or a larger area with lower quality. Two areas in different parts of Sweden are investigated. Box-Cox transformations, which provide flexible functional forms, are used in the empirical analysis and the results indicate that the biodiversity production costs differ between the regions. The major contribution of this paper is that it develops and tests a method of estimating biodiversity production costs on permanent pastures when biodiversity quality differs between pastures. If the method were to be used with cost data, that were more thoroughly collected and covered additional production areas, biodiversity cost functions could be estimated and used in applied policy work.  相似文献   
20.
This paper investigates whether the level of transaction costs of a Swedish agri-environmental policy measure is attributable to technical factors or whether political factors, such as lobby groups and political majorities at the county level, influence the costs. A previous study indicated that political factors may influence the level of transaction costs, but the extreme bounds analysis performed in this paper reveals that those results are fragile. It shows that three of the technical variables are robust with respect to model specifications but that none of the political variables are. Thus, no evidence can be found that political factors influence the level of transaction costs.  相似文献   
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