首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
This paper provides a bridge between the fields of ecological risk assessment (ERA) and radioecology by presenting key biota dose assessment issues identified in the US Department of Energy's Graded Approach for Evaluating Radiation Doses to Aquatic and Terrestrial Biota in a manner consistent with the US Environmental Protection Agency's framework for ERA. Current radiological ERA methods and data are intended for use in protecting natural populations of biota, rather than individual members of a population. Potentially susceptible receptors include vertebrates and terrestrial plants. One must ensure that all media, radionuclides (including short-lived radioactive decay products), types of radiations (i.e., alpha particles, electrons, and photons), and pathways (i.e., internal and external contamination) are combined in each exposure scenario. The relative biological effectiveness of alpha particles with respect to deterministic effects must also be considered. Expected safe levels of exposure are available for the protection of natural populations of aquatic biota (10 mGy d(-1)) and terrestrial plants (10 mGy d(-1)) and animals (1 mGy d(-1)) and are appropriate for use in all radiological ERA tiers, provided that appropriate exposure assumptions are used. Caution must be exercised (and a thorough justification provided) if more restrictive limits are selected, to ensure that the supporting data are of high quality, reproducible, and clearly relevant to the protection of natural populations.  相似文献   

6.
Ecological issues related to ozone: agricultural issues   总被引:29,自引:0,他引:29  
Research on the effects of ozone on agricultural crops and agro-ecosystems is needed for the development of regional emission reduction strategies, to underpin practical recommendations aiming to increase the sustainability of agricultural land management in a changing environment, and to secure food supply in regions with rapidly growing populations. Major limitations in current knowledge exist in several areas: (1) Modelling of ozone transfer and specifically stomatal ozone uptake under variable environmental conditions, using robust and well-validated dynamic models that can be linked to large-scale photochemical models lack coverage. (2) Processes involved in the initial reactions of ozone with extracellular and cellular components after entry through the stomata, and identification of key chemical species and their role in detoxification require additional study. (3) Scaling the effects from the level of individual cells to the whole-plant requires, for instance, a better understanding of the effects of ozone on carbon transport within the plant. (4) Implications of long-term ozone effects on community and whole-ecosystem level processes, with an emphasis on crop quality, element cycling and carbon sequestration, and biodiversity of pastures and rangelands require renewed efforts.The UNECE Convention on Long Range Trans-boundary Air Pollution shows, for example, that policy decisions may require the use of integrated assessment models. These models depend on quantitative exposure-response information to link quantitative effects at each level of organization to an effective ozone dose (i.e., the balance between the rate of ozone uptake by the foliage and the rate of ozone detoxification). In order to be effective in a policy, or technological context, results from future research must be funnelled into an appropriate knowledge transfer scheme. This requires data synthesis, up-scaling, and spatial aggregation. At the research level, interactions must be considered between the effects of ozone and factors that are either directly manipulated by man through crop management, or indirectly changed. The latter include elevated atmospheric CO(2), particulate matter, other pollutants such as nitrogen oxides, UV-B radiation, climate and associated soil moisture conditions.  相似文献   

7.
与传统学科界限鲜明不同,生态经济学强调跨学科交叉研究,注重让问题来决定研究工具集,而不是由研究工具来决定合适的对象。由于生态经济问题涉及生态系统与社会经济系统,研究对象属性多样、关系复杂,既有采用传统意义上的生态经济学方法如生态系统服务价值核算等方法,也包括生活质量、生计途径、消费评估等社会学方法。因此,采取关注学科主要方法发展演化的思路,难以系统地总结生态经济研究进展。我国西北地区生态环境脆弱,经济发展相对落后,无疑是生态经济研究的"天然典型实验场",取得了大量的研究成果。遵循从研究对象出发的思路,采用经典的ImPACTS等式框架,以更宽泛的视野和系统的思维框架综述了西北地区典型生态经济实证研究的思路,即:采用等级层次分析方法研究生态系统和经济系统某个或多个结构性成分及其关系,再用实际结果检验其正确性。综述重要进展包括:可持续性衡量从物质、能量和信息角度开展了水资源承载力、生态足迹、能值与上升性的研究;生态系统服务和自然资本的价值评估开展了条件估值和选择模型,以及环境经济账户、物质流等集成核算工作;人类福利状况评价开展了幸福及生活质量核算工作;开展了生态补偿全流程的实证研究工作;集成模拟模型开展了空间建模环境的构建及简单自然过程的模拟,以LUCC和生态补偿为例进行了较好的自然过程和人文因素相耦合的集成模拟研究;以社会适应性能力作为整体性指标研究了社会资源对水资源的适应作用,将社会资源解耦为文化类型、社会资本和制度三个维度进行实证分析。在此基础上,提出了未来开展研究的建议。  相似文献   

8.
Refining the ecological footprint   总被引:8,自引:0,他引:8  
Ecological footprint measures how much of the biosphere’s annual regenerative capacity is required to renew the natural resources used by a defined population in a given year. Ecological footprint analysis (EFA) compares the footprint with biocapacity. When a population’s footprint is greater than biocapacity it is reported to be engaging in ecological overshoot. Recent estimates show that humanity’s footprint exceeds Earth’s biocapacity by 23%. Despite increasing popularity of EFA, definitional, theoretical, and methodological issues hinder more widespread scientific acceptance and use in policy settings. Of particular concern is how EFA is defined and what it actually measures, exclusion of open oceans and less productive lands from biocapacity accounts, failure to allocate space for other species, use of agricultural productivity potential as the basis for equivalence factors (EQF), how the global carbon budget is allocated, and failure to capture unsustainable use of aquatic or terrestrial ecosystems. This article clarifies the definition of EFA and proposes several methodological and theoretical refinements. Our new approach includes the entire surface of the Earth in biocapacity, allocates space for other species, changes the basis of EQF to net primary productivity (NPP), reallocates the carbon budget, and reports carbon sequestration biocapacity. We apply the new approach to footprint accounts for 138 countries and compare our results with output from the standard model. We find humanity’s global footprint and ecological overshoot to be substantially greater, and suggest the new approach is an important step toward making EFA a more accurate and meaningful sustainability assessment tool.
Jason VenetoulisEmail:
  相似文献   

9.
Ecological scales proposed by H. Ellenberg, E. Landolt, and D.N. Tsyganov have been used to evaluate the roles of three ecological factors—elevation above sea level, soil moisture, and soil nitrogen—in determining the composition of forest communities in the Southern Ural region. The results obtained with all these scales are similar, which indicates that any of them can serve the purpose.  相似文献   

10.
Three interrelated management problems—eutrophication of multiple use shallow lakes, sea level rise and flood risk mitigation and tourism pressures—are analysed in the context of an internationally important wetland area, the Norfolk and Suffolk Broads in the UK. The ecological-economic research findings presented should provide essential information to underpin the regulatory and management process in this internationally important conservation area. The relevant authority somehow has to integrate the maintenance of public navigation rights, nature conservation, and tourism promotion in a highly dynamic ecosystems setting. Because of the stakeholder conflicts, potential and actual, a more inclusionary decision-making procedure is required, and is currently being implemented.  相似文献   

11.
Ecological economics is a field of enquiry that has had, with a few exceptions, an almost entirely terrestrial focus. Given the fundamental ecological and economic importance of oceanic and coastal ecosystems, and the accelerating deterioration of these ecosystems, we argue that there is an urgent case to redress this imbalance. In so doing, the scope of ecological economics will be extended and compelling insights developed and applied to better understand and govern marine systems. Although we acknowledge that there is no unequivocal or unitary view of what might constitute an ecological economics of the oceans and coasts, we assert that it should consist of at least ‘four cornerstones’: (1) sustainability as the normative goal; (2) an approach that sees the socio-economic system as a sub-system of the global ecological system; (3) a complex systems approach; and (4) transdisciplinarity and methodological pluralism. Using these four cornerstones, we identify a future research agenda for an ecological economics of the oceans and coasts. Specifically, we conclude that ecological economists must work with other disciplines, especially those involved in marine policy and practice, to move from a ‘frontier economics’ (which has dominated marine management) to entrench an ‘ecological economics’ of the oceans and coasts as the dominant paradigm.  相似文献   

12.
13.
There has and continues to be concern about the effects of elevated nitrogen (N) deposition on natural ecosystems. In this paper, research on natural ecosystems, including wetlands, heathlands, grasslands, steppe, naturally regenerated forests and deserts, is evaluated to determine what is known about nitrogen cycling in these ecosystems, the effects of elevated nitrogen on them and to identify research gaps. Aquatic ecosystems are not included in this review, except as they are part of the larger ecosystem. Research needs fall into several categories: (1) improved understanding and quantification of the N cycle, particularly relatively unstudied processes such as dry deposition, N fixation and decomposition/mineralization; (2) carbon cycling as affected by increased N deposition; (3) effects on arid ecosystems and other "neglected" ecosystems; (4) effects on complex ecosystems and interactions with other pollutants; (5) indicators and assessment tools for natural ecosystems.  相似文献   

14.
Environment, Development and Sustainability - The article “Quantifying carbon footprint for ecological river restoration”, written by “Yiwen Chiu, Yi Yang and Cody Morse”,...  相似文献   

15.
16.
The need for understanding the factors that trigger human responses to climate change has opened inquiries on the role of indigenous and local ecological knowledge (ILK) in facilitating or constraining social adaptation processes. Answers to the question of how ILK is helping or limiting smallholders to cope with increasing disturbances to the local hydro-climatic regime remain very limited in adaptation and mitigation studies and interventions. Herein, we discuss a case study on ILK as a resource used by expert farmer-fishers (locally known as Caboclos) to cope with the increasing threats on their livelihoods and environments generated by changing flood patterns in the Amazon delta region. While expert farmer-fishers are increasingly exposed to shocks and stresses, their ILK plays a key role in mitigating impacts and in strengthening their adaptive responses that are leading to a process of incremental adaptation (PIA). We argue that ILK is the most valuable resource used by expert farmer-fishers to adapt the spatial configuration and composition of their land-/resource-use systems (agrodiversity) and their produced and managed resources (agrobiodiversity) at landscape, community and household levels. We based our findings on ILK on data recorded for over the last 30 years using detailed ethnographic methodologies and multitemporal landscape mapping. We found that the ILK of expert farmer-fishers and their “tradition of change” have facilitated the PIA to intensify a particular production system to optimize production across a broad range of flood conditions and at the same time to manage or conserve forests to produce resources and services.  相似文献   

17.
18.
19.
20.
Oil spill response, whether planned by government agencies, oil spill cooperatives or individual companies, can be planned and carried out with the goal of minimizing ecological impacts, not merely removing visible oil. Two oil spill cooperatives on the west coast are implementing such planning. First, a coastal survey was conducted in the cooperative's area of responsibility. Physical processes and habitat types were examined. Oil spill cleanup guidelines were written for each habitat type. Biologically sensitive areas, those sites most vulnerable to oil spill impacts, were identified. Strategies were developed to protect most sensitive areas, i.e., prevent spilled oil from reaching them. Protection is the preferred option because it prevents both the impact of the oil and subsequent cleanup activities. Protected areas can often serve as repopulation centers for surrounding sites that may have been impacted. If minimizing ecological impact is to be a prime focus of oil spill response, ecologists should be involved in both the planning before and the field efforts during such spill events.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号