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261.
Ecosystems are dynamic complexes. These dynamics can be described by different ecophysiological parameters and systems theoretical concepts like succession, thermodynamics, information/network theory, resilience, adaptability and the orientor concept. In this paper, different indicators and concepts are linked to Holling's adaptive cycle metaphor in order to derive hypotheses on potential system trajectories. The hypotheses focus on an exemplary temperate forest ecosystem experiencing the adaptive cycle's four phases of exploitation, conservation, collapse and reorganization after an initializing fire event. The different properties are correlated to the number of total system connections and show varying trajectories. Additionally, the provision of selected forest ecosystem services during the different phases is hypothesized and compared to three other land use types. 相似文献
262.
目前化工行业及化学工业园区的安全准入主要依据是现行的法律、规范和标准,而化学工业及化工园区的飞速发展使得现有的规范、标准等存在严重地滞后性,远远不能满足化工园区区域安全准入及风险承载核算的要求。论文针对化工园区目前建设及发展状况,主要分析化工园区安全准入的内涵、现存状况及存在的局限性,构建化学工业园区规划及企业安全准入的基本理论框架,研究思路从化学工业园区的定性、定量风险着手,阐述准入的具体步骤、关键把握的重点以及风险承载状况,并针对国外的风险容许标准,确定适合我国化工园区的风险准入准则,最后提出下一步的研究重点,对指导我国目前化工园区安全准入具有一定的理论和现实意义。 相似文献
263.
264.
Evaluating the efficacy of adaptive management approaches: Is there a formula for success? 总被引:1,自引:0,他引:1
Within the field of natural-resources management, the application of adaptive management is appropriate for complex problems high in uncertainty. Adaptive management is becoming an increasingly popular management-decision tool within the scientific community and has developed into two primary schools of thought: the Resilience-Experimentalist School (with high emphasis on stakeholder involvement, resilience, and highly complex models) and the Decision-Theoretic School (which results in relatively simple models through emphasizing stakeholder involvement for identifying management objectives). Because of these differences, adaptive management plans implemented under each of these schools may yield varying levels of success. We evaluated peer-reviewed literature focused on incorporation of adaptive management to identify components of successful adaptive management plans. Our evaluation included adaptive management elements such as stakeholder involvement, definitions of management objectives and actions, use and complexity of predictive models, and the sequence in which these elements were applied. We also defined a scale of degrees of success to make comparisons between the two adaptive management schools of thought. Our results include the relationship between the adaptive management process documented in the reviewed literature and our defined continuum of successful outcomes. Our data suggest an increase in the number of published articles with substantive discussion of adaptive management from 2000 to 2009 at a mean rate of annual change of 0.92 (r2 = 0.56). Additionally, our examination of data for temporal patterns related to each school resulted in an increase in acknowledgement of the Decision-Theoretic School of thought at a mean annual rate of change of 0.02 (r2 = 0.6679) and a stable acknowledgement for the Resilience-Experimentalist School of thought (r2 = 0.0042; slope = 0.0013). Identifying the elements of successful adaptive management will be advantageous to natural-resources managers considering adaptive management as a decision tool. 相似文献
265.
Inland water bodies are considered as integrated parts of the landscape and the monitoring of water quality and aquatic resources need to be addressed on a regional basis for optimal assessment and management. In this study, a simple stratified sampling scheme was applied to a mesoscale survey of western and northwestern Irish lakes, which was carried out to identify, based on the distribution patterns of phytoplankton biomass, potential associations between lake trophic state and land cover attributes. Phytoplankton community analysis was also performed to determine whether taxa associations reflected meteorology-linked aestival succession or specific spatial distributions. The assessment was based on the typology of hydrogeomorphological and land cover attributes of river catchments through ArcGIS analysis. Sampling was carried out in 50 lakes and during a 15-week period in summer 2009. Results showed a general longitudinal gradient in the trophic status of the lakes sampled, with a greater frequency of mesotrophic lakes in the eastern part of the study area where land cover is dominated by agricultural surfaces. Significant relationships (p < 0.010) were found between chlorophyll-a concentration and the proportion of river catchment surface covered by agriculture land and wetlands, findings which might be considered further as proxies for developing an eutrophication risk index. Multivariate analysis of phytoplankton community data clustered the sampled lakes into three assemblages, with ordination along axis 1 being significantly correlated to time and temperature (p < 0.006). There was greater frequency of occurrence of diatoms in lakes from cluster III (Kruskal–Wallis, p < 0.05, H = 6.34, df = 2, n = 49), concomitant to lower chlorophyll-a concentrations, lake surface temperatures and Secchi depths, reflecting meteorological conditions dominated by precipitations. Those results support the potential of mesoscale surveys to assess water quality variables and detect environmental patterns at regional scales. 相似文献
266.
Research conducted on organisations that are able to sustain excellent safety records over long time periods suggests that there are a number of practices that organisations can adopt to achieve high levels of reliability and safety. These practices are often discussed in the context of major incidents to highlight the safety standards that high hazard organisations should try to emulate. However, previous research has predominantly focused on non-profit organisations, and comparatively little research has examined whether high reliability practices may be meaningfully applied to commercial contexts. This paper addresses this gap by using a qualitative approach to explore the types of reliability-enhancing practices implemented in a UK-based oil refinery in its attempt to achieve its ethos of ‘safe and reliable operations’. The findings illustrate the successful application of reliability-enhancing practices in several domains, including: hazard identification and control; emergency preparedness and collection; and analysis of incidents and near misses. Management commitment to safety emerged as an important factor underpinning the successful implementation of reliability-enhancing practices, highlighting its potential significance in the context of commercial organisations. However, promoting an open reporting culture and maintaining high levels of management visibility may be some of the challenges encountered by organisations striving to implement reliability-enhancing practices. 相似文献
267.
Ruobin Dai Hongyi Han Yuting Zhu Xi Wang Zhiwei Wang 《Frontiers of Environmental Science & Engineering》2022,16(4):40
268.
耕地质量指标体系的构建 总被引:8,自引:0,他引:8
根据土地质量的概念及其影响因素,构建了耕地质量指标体系。认为耕地质量的影响因素包括自然、社会和经济因素,而PSR(压力——状态——响应)框架则是构建耕地质量指标体系的最佳思路。在此基础上提出具体评价指标,其中生态功能指标体系包括土壤质量、气候质量、生物多样性质量和景观生态质量,生产功能指标体系(即耕地生产力)则通过耕地生产潜力、耕地基础地力和耕地现实生产力进行评价。 相似文献
269.
土地利用系统健康评价的框架与指标选择 总被引:16,自引:1,他引:15
随着社会经济的发展,人类行为对生态系统产生越来越大的影响,生态系统的健康状况也引起了国内外学者的普遍关注,作为一个以土地利用为基础的自然、经济、社会复合的土地利用系统。它既具有生态系统的一般特征。又具有其本身的特殊性,集中体现了人口增长、经济发展与资源短缺的矛盾。因此,为了人类可持续发展。必须关注土地利用系统的健康状态。本文在对土地利用系统的分析基础上,提出土地利用系统健康的概念,土地利用系统健康评价的本质、目的,并初步建立了土地利用系统健康评价框架体系。 相似文献
270.
Wendy M. Miller 《Local Environment》2015,20(10):1194-1214
The number of urban food initiatives in many regions of the world, notably Europe and the USA, has burgeoned in recent years, and analyses of the impacts of these activities on people and environments are the focus of an increasing academic literature. The impacts documented include enhanced food security, cohesive neighbourhoods, sustainability, and food justice. Yet, another literature presents opposing analyses and focuses on exclusionary aspects of projects and their enabling of a continued neo-liberal reduction in state welfare provision. As a result, there has been an impasse in debates over the potential of urban food projects to reduce inequalities. This paper proposes that the benchmark of the UK allotment system provides a means to examine these opposing positions. It uses the conceptual frameworks of diverse economies and the capital assets framework to attain clarity in the analysis of the many kinds of food-related activities seen in (peri-)urban areas. Drawing on empirical work in Plymouth, UK, it focuses on the potential of the different food ventures to reduce inequalities, given certain contingent economic and political factors. It also presents evidence that the allotment movement despite its initially radical roots can be seen as largely apolitical in the present day and has no leverage over allocation of land to allotment sites. Even so, evidence is growing that both allotments and the newer forms of urban food activities contribute to meeting national and city-level policy objectives, with the potential to enhance food justice and reduce inequalities. 相似文献