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971.
Metropolitan Shanghai, in Yangtze River Delta (YRD), plays undoubtedly the leading role in the economic development in China, and becomes one of the most important population congregation areas. It is also widely regarded as the sixth uprising urban agglomeration in the world. Based on the quantitative studies on basic socioeconomic and demographic profile on the number and transition of population, this paper concluded that the migration is the key factor for population dynamics in YRD. Then, what are the regional economic factors affecting the migration of different cities in YRD? The panel data show that the different wage level is the most important factor that affects the immigration in YRD. Moreover, the ratio of industry sector and service sector has an impact on attracting immigration. However, per-capital GDP and the share of foreign direct investment (FDI) to GDP have dual-side impact: not high per-capital GDP and FDI bring the high immigration.  相似文献   
972.
The Critical Ecosystems Team of the US Environmental Protection Agency (EPA), Region 5, has developed an approach to prioritize and target ecologically high-quality areas for enhanced environmental protection in the Midwestern states of Illinois, Indiana, Ohio, Michigan, Minnesota and Wisconsin. Using this approach, we intend to employ a pro-active strategy to protect the environment by protecting and restoring natural ecosystems rather than the traditional EPA approach of remediating and attempting to restore already degraded habitats. The approach consists of two components: (1) partnership and (2) criteria. For the partnership component, we collected, mapped, and summarized information on ecosystems considered critical to federal and state agencies, tribes and non-profit organizations. Multi-county areas with high numbers of ecosystems identified by a variety of partners were designated as ‘Ecologically Rich Regions’. These Ecologically Rich Regions highlight broad geographic areas where there are high levels of partner interest and, correspondingly, areas with high potential for forming collaborative partnerships for enhanced environmental protection. The second component, which relies on criteria, is still under development and defines critical ecosystems as having three important properties: (1) high ecological diversity, (2) potential for long-term sustainability and (3) presence of relict native ecosystems or communities. The information compiled under both components of this ecosystem targeting approach will inform ecological risk managers and assessors about important ecosystems that should be considered in risk management and assessment processes.  相似文献   
973.
ABSTRACT: This paper examines the potential to manage Mississippi River water levels for ecological benefits. The study focuses on the Weaver Bottoms, a 4,000 acre backwater marsh in southeastern Minnesota (Pool 5) highly valued for fish and wildlife habitat. The Weaver Bottoms has suffered increasing loss of aquatic vegetation and associated habitat degradation since the 1960s, largely due to persistent high water, sedimentation, wave re-suspension of sediments, and poor light penetration. In other reaches of the Mississippi River, water level reductions exposing backwater sediments have produced strong vegetative responses due to subaerial exposure of seeds and sediment compaction. Water level management scenarios for Pool 5 were developed using the HEC-2 water surface profile model. Results indicate that in many years it would be possible to reduce water levels sufficiently to expose much of the Weaver Bottoms, generating a substantial vegetative response. Additional benefits could be expected since both sediment compaction and increased vegetation would reduce re-suspension of sediments. Shifting management priorities to improve habitat would temporarily impact many river users, including both commercial and recreational boaters. Water level reductions must be coordinated with their needs.  相似文献   
974.
A concept concerning the functional isomorphism of natural ecosystems as a factor modulating climatogenic changes in the soil–plant cover is proposed. On an empirical basis, production and destruction types of isomorphism are distinguished, which differ in their prevailing influence on the dynamics of zonal and regional ecosystems in the boreal and subboreal belts.  相似文献   
975.
太湖流域水污染实质与集成化流域管理   总被引:4,自引:1,他引:3  
本文分析了太湖流域面源性水环境污染问题及其治理机制 ,在此基础上指出面源污染的深层原因是传统粗放型经济增长方式 ;生活方式的过物质化、城乡二元结构及城乡空间布局的不合理等社会经济运行机制的不可持续性 ,并对建立适应面源污染的综合性、集成化和流域性的水环境管理体制提出了突破性的改革思路  相似文献   
976.
Three collectives of substances - plastics, plant nutrients, biotoxins - are candidates for monitoring programmes that could keep track of the quality of ocean waters for vital life processes. All three are not subject to systematic surveillance at present. They are each characterized by long residence times in the marine environment, by increasing influx, and by growing evidence of their deleterious impacts on living systems.  相似文献   
977.
长江经济带近年来上升为新一轮的国家战略,然而区域内生态环境面临严峻压力,生态环境保护关系到其有序开发与可持续发展。新环保法的出台与实施为长江经济带开发过程中生态环境保护工作提供了有力的制度保障。从生态环境退化、物种持续减少、环境事故高发等7个方面剖析了我国生态环境问题的趋向,并从明确政府环境责任、解决违法成本低等5个方面对新环保法展开解读,然后基于综合规划、合理布局、严守红线、优化技术、地方立法、依法行政、降低风险、公开信息与共同参与等9个方面对长江经济带的环保执法进行探讨,以期为新时期长江经济带开发法制建设提供参考。  相似文献   
978.
云南气候变化高分辨率模拟与RCP4.5情景预估   总被引:1,自引:0,他引:1  
利用高分辨率区域气候模式CCLM(COSMO Model in Climate Mode)对云南省气温和降水的模拟资料,采用多种评价指标,对比分析了试验期(1961~2005年)的模拟结果与同期25个气象站的观测值,并对RCP45情景下的近期(2030~2040年)气温可能变化趋势进行了预估。结果表明:(1)CCLM区域气候模式能够较好地模拟云南省气温的演变趋势,而对降水的模拟能力相对较弱;(2)RCP45情景下,年平均气温(T)、最高气温(Tmax)和最低气温(Tmin)将呈现一致上升趋势,2030~2040年比基准期1986~2005年上升幅度均为12℃;(3)2030~2040年,云南省暖事件发生的可能性将增加,冷事件可能有所减少  相似文献   
979.
In this study,we identified ecological pressures on grassland ecosystems and adaptive countermeasures in Northern China.Our research revealed that the main sources of these pressures included population growth,economic development,resources exploitation,and global climate change,with human-related activities being overriding factors.Overgrazing was an important reason for grassland imbalance,causing soil erosion and desertification,especially during the sensitive spring greening phase.In steppe zones,commercial coal mining was destructive to the ecological environment.Regarding long-term strategies,we recommend that policy-makers devote more consideration to a new conceptual approach for transforming grasslands through shifting the focus from die grassland’s traditional production functions to meir ecological functions.Applying this concept,adaptive countermeasures should be developed to reduce human impacts based on the environmental capacities of grasslands.Moreover,we recommend the development of environment-friendly industries and reduction of pressures from human activities as effective measures for maintaining the balance between sustainable economic development and grassland conservation.Lastly,we suggest that restoration of degraded grasslands should conform to the principle of natural vegetation to further improve the ecological adaptability of plants and ecosystem stability.This study is expected to provide scientific support for policy-makers engaged in grassland protection.  相似文献   
980.
The Perth region is one of the 56 designated Natural Resources Management (NRM) regions in Australia. A community-led body – Perth Region NRM (PRNRM) – is in charge of overseeing NRM initiatives in the region. PRNRM heavily relies on Environmental Care Organisations (ECOs) that are involved in a wide variety of activities ranging from managing nature reserves to restoring ecosystems on a voluntary basis. While ECOs have become an integral component of PRNRM, they are often vulnerable because of the uncertain availability of financial and human resources. The way these organisations can overcome resource scarcities and become resilient is therefore significant for the effective delivery of regional NRM arrangements. However, what makes some ECOs in the Perth region more resilient than others is not well understood. This paper responds to this gap and explores the state of ECOs in the Perth region. The paper begins by reviewing the notion of resilience using a social capital lens. Drawing on a survey of ECOs and interviews, the method used for data collection and data analysis is presented next. Finally, the paper makes a case for fostering social capital as a way of enhancing the resilience of ECOs in the Perth region and beyond.  相似文献   
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