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51.
52.
Since the United Nations Conference on Environment and Development (UNCED) [1992, Agenda 21: programme of action for sustainable development. United Nations Conference on Environment and Development (UNCED), 3-14 June 1992. Rio de Janeiro, Brazil, 294pp.], the management of information has become central to the management of forest resources. In the cases of North America and Europe, similar issues have been challenging policy makers as they determine the information suitable for monitoring progress towards sustainable forest management (SFM). Using an 'online' survey, this research explored multiple stakeholder perspectives on monitoring and information reporting for SFM in different jurisdictions. The research was based on the premise that an analysis of the variation in stakeholder observations across a range of SFM 'issue areas' could provide valuable insight into the perceived need for SFM-related monitoring and information reporting in the regions of Europe, Canada and the USA. Despite the traditional limitations associated with exploratory survey research, the results indicate a demand for more information on SFM-related issues. The results also highlight the degree to which the perceptions of a sample of stakeholders can differ between Europe, USA and Canada. While these results cannot be generalized beyond the present study, they do suggest that further studies are needed to understand stakeholder perspectives on forestry-related monitoring and information reporting in different jurisdictions. 相似文献
53.
以国家城乡融合发展试验区——重庆西部片区为研究区,以2009年、2014年、2019年为研究时点,以2009—2019年为研究时段,按照思想缘起、理论基础、实证演绎、提升路径的研究思路,建立乡村人居环境系统韧性测度的指标体系,分析其演变规律。研究结果表明:2009—2019年,重庆西部片区的乡村人居环境系统韧性水平不断上升,呈现出“南高北低”的空间格局。各子系统韧性在时间上呈现出不同程度的增长趋势,在空间上差异明显:自然系统韧性与人类系统韧性分别呈现出“由南向北递减”和“东西部向中部递减”的空间格局;居住系统韧性与支撑系统韧性则分别呈现出由“低值点缀分布”逐渐过渡到较为均衡和“普遍均衡、高低值点缀”的空间格局;社会系统韧性表现为“西部增强、东部减弱”的空间格局特征。借助障碍度模型对重庆西部片区乡村人居环境系统韧性提升的障碍因子及不同区县面临的主导障碍进行诊断,根据结果将重庆西部片区划分为单一主导障碍型、双重障碍型与三层障碍型三种类型,据此设计乡村人居环境系统韧性提升的差异化路径,以期打破重庆西部片区乡村人居环境系统韧性提升的多重制约。 相似文献
54.
This report summarizes the results of two studies of electricity supply for Europe (EU), the Middle East (ME) and North Africa
(NA) up to the year 2050. It shows that a transition to competitive, secure and sustainable supply of electricity and water
is possible using renewable energy sources, efficiency gains and fossil fuel backup for balancing power. A strong cooperation
between the EU and MENA for the market introduction of renewable energy and the interconnection of the electricity grids by
high-voltage direct-current transmission are keys to the success and survival of the whole region. However, the necessary
measures will take at least two decades to become effective. Therefore, adequate policy and economic frameworks for their
realization must be introduced immediately. The importance of sustainable energy for the security of freshwater supplies in
MENA is also described.
相似文献
Hans Müller-SteinhagenEmail: |
55.
杨英 《长江流域资源与环境》2008,17(2):212-212
为了解不同植被类型土壤水资源的变化规律,选择南水北调中线水源区宁陕县寨沟区域典型植被针阔混交林、针叶林、板栗林、灌木林、荒坡草地和坡耕地为研究对象,通过样地调查与实验分析的方法对其土壤水分物理特征及有机质含量进行测定研究。结果表明,各种有林地的土壤容重、孔隙度和有机质等理化特征均优于荒坡和坡耕地;针阔混交林土壤含水量最高,蓄水能力明显好于其它植被类型;在垂直剖面上,各种植被类型坡地土壤含水量和饱和蓄水量随土壤深度的增加基本呈递减趋势,但有林地下降幅度较大,表层含水量明显高于荒坡与坡耕地表层。由此可见,在涵养水源方面,针阔混交林最好,针叶林、板栗林与灌木林次之,荒坡与坡耕地较差。 相似文献
56.
Characteristics and recent trends of sulfur dioxide at urban, rural, and background sites in North China: Effectiveness of control measures 总被引:4,自引:0,他引:4
SO2 measurements made in recent years at sites in Beijing and its surrounding areas are performed to study the variations and trends of surface SO2 at different types of sites in Northern China. The overall average concentrations of SO2 are (16.8 ± 13.1) ppb, (14.8 ± 9.4) ppb, and (7.5 ± 4.0) ppb at China Meteorological Administration (CMA, Beijing urban area), Gucheng (GCH, relatively polluted rural area, 110 km to the southwest of Beijing urban area), and Shangdianzi (SDZ, clean background area, 100 km to the northeast of Beijing urban area), respectively. The SO2 levels in winter (heating season) are 4-6 folds higher than those in summer. There are highly significant correlations among the daily means of SO2 at different sites, indicating regional characteristics of SO2 pollution. Diurnal patterns of surface SO2 at all sites have a common feature with a daytime peak, which is probably caused by the downward mixing and/or the advection transport of SO2-richer air over the North China Plain. The concentrations of SO2 at CMA and GCH show highly significant downward trends (-4.4 ppb/yr for CMA and -2.4 ppb/yr for GCH), while a less significant trend (-0.3 ppb/yr) is identified in the data from SDZ, reflecting the character of SDZ as a regional atmospheric background site in North China. The SO2 concentrations of all three sites show a significant decrease from period before to after the control measures for the 2008 Olympic Games, suggesting that the SO2 pollution control has long-term effectiveness and benefits. In the post-Olympics period, the mean concentrations of SO2 at CMA, GCH, and SDZ are (14.3 ± 11.0) ppb, (12.1 ± 7.7) ppb, and (7.5 ± 4.0) ppb, respectively, with reductions of 26%, 36%, and 13%, respectively, compared to the levels before. Detailed analysis shows that the differences of temperature, relative humidity, wind speed, and wind direction were not the dominant factors for the significant differences of SO2 between the pre-Olympics and post-Olympics periods. By extracting the data being more representative of local or regional characteristics, a reduction of up to 40% for SO2 in polluted areas and a reduction of 20% for regional SO2 are obtained for the effect of control measures implemented for the Olympic Games. 相似文献
57.
为探明北运河流域(北京段)多层沉积物中PAHs(多环芳烃)的污染状况,利用活塞式底泥取样器于2014年11月采集了9处沉积物样品,取样深度为30~80 cm,每处样品根据其垂向介质特征大致分成3~4层,分别测定各层样品的粒径、TOM(总有机质)及16种PAHs的质量分数,探讨PAHs在河道沿程与垂向上的分布特征、来源及生态风险评价.结果表明,北运河流域(北京段)沉积物以砂质壤土为主,w(TOM)(以干质量计,下同)为103.4~146.8 g/kg,w(∑16PAHs)为598.1~28 730.6 ng/g,各层w(∑16PAHs)为108.5~8 810.8 ng/g.沉积物中PAHs以高环为主,主要包括有Phe(Phenanthrene,菲)、Fla(Fluoranthene,荧蒽)、Pyr(Pyrene,芘)、BbF〔Benzo(b)fluoranthene,苯并[b]荧蒽〕.在河道沿程变化上,中下游沉积物的污染程度远高于上游.在垂向变化上,w(TOM)和沉积物粒径对PAHs的分布影响有限,PAHs的垂向分布主要受所处沉积环境与历史污染程度影响.根据主成分分析与同分异构体比值法推断,PAHs主要来源于化石燃料与生物燃料的燃烧,少部分为石油源.利用效应区间值得出的生态风险评价结果表明,北运河流域(北京段)沉积物中PAHs可能已对环境产生负面影响,其中BbF、BkF、InP与BgP已对环境产生毒副作用,需要给予关注与解决. 相似文献
58.
瀑河水库蓄水后水质变化预测 总被引:2,自引:0,他引:2
瀑河水库拟作为南水北调中线的一个调蓄水库。在瀑河水库淹没区内布10个采样点,分别采集0-20、20-40、40-60cm深度的土壤,实验室中模拟水库蓄水淹没情景,连续监测“库水”水质,试验表明:蓄水初期土壤中营养物质溶出对库水水质有一定影响,且随着时间的推移,各营养物质溶出的速度及浓度变化不同,蓄水16天后浓度趋于平稳,库水水质达到地表水环境质量Ⅱ类标准,将模拟值作为初始值,利用WQRRS模型进行运行期水质预测,得到结论为:(1)当调水水质为Ⅰ和Ⅱ类标准值的中值、流域汛期径流水质为Ⅱ-Ⅴ类时,预测库水水质为Ⅱ-Ⅲ类;(2)当调水水质为Ⅱ类标准值的下限值、流域汛期径流水质为Ⅱ-Ⅴ类时,预测库水水质大多为Ⅲ类,部分情况下为Ⅳ类,且N、P超标;(3)当调水水质为Ⅰ和Ⅱ类标准值的中值、流域径流水质为Ⅱ类时,在2010、2020和2030水平年水库水质全部为Ⅱ类;当调水水质为Ⅱ类标准值的下限值时库水水质则为Ⅲ类。 相似文献
59.
60.
本文分析了贵州西部环境灾害的形成原因,它既受自然因素的影响,也受人类活动的影响。并提出了防治贵州西部环境灾害的基本措施。 相似文献