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1.
厘清城市生态效率的时空分异及其驱动因素是实现长江经济带协同绿色发展的基本前提。本文基于2003—2018年城市数据,采用Min DS模型测度了长江经济带城市生态效率水平,从投入产出视角揭示了城市生态无效率的具体来源,进一步利用Theil指数及地理探测器等方法实证考察了城市生态效率的时空分异特征及其驱动因素。研究发现:①样本考察期内,长江经济带总体及上、中、下游城市生态效率水平呈现波动上升趋势,且下游地区始终高于中、上游地区。期望产出不足和非期望产出冗余是造成城市生态无效率的重要原因。②地区内差异是长江经济带城市生态效率空间差异的主要来源。2011年之前下游地区内部生态效率差异对总体差异的影响最大;2011年之后下游与上游地区内差异贡献交替位于前两位。③长江中、下游地区城市生态效率的绝对差异呈显著缩小态势,但上游地区稍有扩大。除中游地区外,长江经济带城市生态效率具有一定的梯度效应,且下游地区的两极分化现象最为明显。④长江经济带城市生态效率的空间分异受到多种因素的综合影响,从结构因素来看,经济发展差异对长江经济带城市生态效率空间差异的决定力始终最高,能源投入差异和污染排放差异的作用强度相对较小;从社会经济因素来看,人口密度差异对城市生态效率空间分异的决定力显著强于其他因素。  相似文献   

2.
旅游生态效率是一种以"最小资源投入和环境破坏,最大经济社会产出"为核心目标,衡量旅游永续发展的重要指标。综合运用基于非期望产出的Super-SBM模型、地理空间分析方法和面板Tobit回归模型探索长江经济带2007~2016年旅游生态效率时空演变特征及其影响因素。结果表明:(1)研究期内,高效率省区主要分布于东部地区,较低效率省区分布广泛,其数量先减少后增加;而低效率省区数量较少,其分布范围总体从长江经济带东部向西部迁移。(2)长江经济带旅游生态效率区域差异性和集聚性均不断缩小,东部、中部和西部3地区内部差异是长江经济带区域差异的主要贡献者。(3)旅游经济规模、旅游产业结构、科技发展水平、城镇化发展水平和政府规制力度对各省区旅游生态效率影响的空间异质性较强。  相似文献   

3.
科学剖析农用地生态效率时空差异及影响机制,对实现农用地利用与资源环境协调发展以及制定农业可持续发展政策具有重要的理论与实践意义。将农用地面源污染、碳排放作为非期望产出纳入农用地生态效率评价指标体系,借助SBM-Undesirable模型对1990~2017年江西省农用地生态效率进行测度并对其时空差异特征进行分析,在此基础上运用Tobit模型探讨相关因素的影响机制。结果表明:(1)1990~2017年间江西省农用地生态效率呈现"先下降后上升"的变化趋势,均值为0.749,总体呈现上升的趋势;(2)各设区市农用地生态效率空间格局演变轨迹呈现先下降后上升的扁平"U"型特征,高效率地区由"连片"分布向"点状"分布再向"连片"分布变化,空间格局趋于非均衡化发展;(3)农村居民人均可支配收入、复种指数、农村劳动力文化程度和劳均播种面积对农用地生态效率产生显著正影响,城乡收入差距则产生显著负影响。最后,从优化资源要素配置、加强农业科技创新应用、健全农村土地流转制度、摒弃过度依赖资源要素投入与环境污染的粗放型发展模式、走"精耕细作"和可持续发展的农业生态文明发展道路等方面提出了提高农用地生态效率的政策建议。  相似文献   

4.
基于2002~2016年的省级面板数据,以农业水资源利用过程中的化肥源面源污染、厩肥源面源污染、灌溉过程碳排放及农药流失作为非合意产出,构建了以"蓝水-绿水"为中心的水资源分析框架,借助SBM模型和Malmquist-Luenberger指数,探析我国农业水资源利用过程的绿色技术进步情况,利用空间面板模型重点考察绿色技术进步、农业经济发展水平与农业水资源利用过程的污染排放之间的关系。化肥源面源污染排放量和农药流失量均表现出空间聚集的特性;在其他投入和产出不变的的既定条件下,促进农业水资源利用过程中的绿色技术进步能够缓解农业污染的局面;将农药流失污染作为非合意产出的农业水资源利用绿色技术进步带来的环境污染减排积极影响更强;农业经济发展水平与4类污染排放分别体现为倒N型、倒U型、正N型和倒N型的关系,随着农业经济发展水平的提升,我国绝大多数地区仍处于农药、化肥粗放使用的倒N型的上升阶段,农药流失和化肥施用引起的面源污染情况仍在加剧,农业经济发展水平与厩肥还田造成的面源污染相分离的状态逐渐消失,而农业水资源利用过程中产生的碳排放污染情况则不容乐观,大部分地区农业灌溉所产生的碳排放面临快速上升的趋势。  相似文献   

5.
鄱阳湖生态经济区农业循环经济发展综合评价   总被引:2,自引:0,他引:2  
发展农业循环经济是鄱阳湖生态经济区建设的关键,农业循环经济发展的目标是实现农业生产经济效率和生态环境效率的双赢。应用DEA方法以评价循环农业发展的经济效率,采用农业生产的生态足迹以反映农业循环经济发展的生态效率。在此基础上,为同时体现农业循环经济发展的经济效率和生态效率,构造了区域农业循环经济发展评价的综合指数,并对鄱阳湖生态经济区的农业循环经济发展进行评价分析。结果表明,大部分地区存在农药化肥投入冗余、粮食单产不足以及农业生产的耕地足迹和牧草地足迹所占比重偏大等问题,为此必须在推广猪-沼-粮的同时,调整农业产业结构,着力发展猪(牛)-沼-果(渔)等循环农业模式,进而提高鄱阳湖生态经济区农业生产的投入产出效率,降低农业生产的生态占用  相似文献   

6.
农地流转和多种形式规模经营,是发展现代农业的必由之路。农业现代化要求农业走可持续发展道路,注重发挥农业的生态环境功能。文章基于2005—2018年26个省份的面板数据,结合水足迹理论和SFA模型测度了各省每年粮食生产的生态效率,探究了农地流转对粮食生产生态效率的影响,得出以下结论和建议:(1)从时间序列来看,中国粮食生产生态效率整体上呈波动性上升趋势,其中山西省、江苏省、安徽省、福建省、江西省、湖北省、重庆市、四川省和云南省生态效率的上升趋势在1%的显著水平上显著,山东省、广东省、海南省却呈显著下降趋势。(2)基于空间分布的角度,地区上大致是呈现东部地区中部地区西部地区的生态效率分布,江苏省粮食生产生态效率最高,湖南省最低。(3)农地流转对粮食生产生态效率具有显著的促进作用,根据分组分析发现,农地流转水平为中等的省份生态效率平均值最高,低水平和高水平的省份生态效率平均值相近,一定程度上表明在加快农地流转促进农业生态化建设的道路上要注重适度规模经营。  相似文献   

7.
在中国耕地非农化日趋加剧,耕地抛荒、撂荒、低效粗放利用等现象愈演愈烈,耕地污染问题日益突出的背景下,提高耕地利用效率对于促进耕地可持续利用,实现耕地利用与资源环境协调发展具有重要的现实意义。本文采用单元调查评估法及碳排放系数公式对中国耕地利用过程中面源污染和碳排放的产出量进行评估,并使用非期望产出的窗式SBM模型对1993-2013年中国耕地利用效率进行重新估算,进而对耕地利用效率的时空分异特征及改进途径进行分析。主要结论:从时间分异特征来看,中国耕地利用效率呈现出显著下降的变化趋势;种植业大省耕地利用低效率现象逐步增强;投入冗余对耕地利用效率的负作用最大且趋于增强;非期望产出冗余对耕地利用效率的负作用次之且趋于增强;面源污染和碳排放的过量产出与耕地利用效率提升的矛盾日益加剧。从空间分异特征来看,耕地利用高效率地区大幅减少,分布状态由"连片"分布向"点状"分布于东部和西部地区转换;低效率地区以中部地区为中心向东部和西部地区扩张;耕地利用效率呈现出严重的"两级分化"特征。从改进途径来看,中国耕地利用效率的改进潜力主要在减少耕地利用投入冗余和降低非期望产出两个方面。  相似文献   

8.
"城市矿产"的资源化循环利用,是我国缓解资源瓶颈约束、构建产业生态化体系的重要手段之一,探究"城市矿产"产业生态效率特征及关键驱动因素,以期为我国继续推动该产业新旧动能转换、生态化转型升级提供参考。本文基于非期望产出的超效率SBM模型,测算我国2004—2017年26个省市层面生态效率,并分析其总体演变、区域差异及空间相关性特征,采用空间计量模型探寻该产业生态效率影响因素。结果表明:(1)"城市矿产"产业生态效率呈"类峰峦"结构的波动上升趋势,从2004年0.87上升至2017年1.06,这期间,峰顶和峰谷省市的该产业生态效率年均差值近12%,且存在较显著的区域差异特征,整体表现为东部地区始终高于中部和西部地区。(2)通过空间相关性分析发现,26个省市该产业生态效率存在较强的空间关联性,整体由低值集聚向中高值集聚状态转变,但发展后期,部分省市脱离整体趋势,出现"微分异"现象。(3)根据空间计量模型估计结果,技术创新是提高该产业生态效率的核心因素;产业发展水平和产业集聚水平为次要因素;环境规制与产业结构为一般影响因素;宏观调控与对外开放水平则无显著影响。最后,提出内外技术联合提高创新能力、以绿色产业合作提升产业集聚水平、环境标准细化增强环保效应、与制造业层级嵌套完善回收体系等对策建议,提升"城市矿产"产业生态发展水平。  相似文献   

9.
农业生态效率是衡量农业可持续性的重要指标,是影响中国农业可持续发展的重要问题之一。选取2008~2019年长江经济带9省2市的相关数据,采用考虑非期望产出的两阶段Super-NSBM模型测算长江经济带的农业生态效率与分阶段效率,并借助核密度分析方法和Tobit模型考察区域农业生态效率的时空特征与影响因素。结果表明:(1)研究期间,长江经济带农业生态效率均值小于1,未达到DEA有效。上、中、下游农业生态效率均值分别为0.932、0.845、1.177,呈现下游>上游>中游的趋势,各省市间存在显著差异。(2)从地区来看,仅江苏省在两阶段实现了DEA有效;江西、贵州、上海、四川为DEA弱有效省份。(3)农业生态效率及其分阶段效率受农业机械化水平、农业种植结构调整的正向影响,受农业受灾率的负向影响。农业市场化程度、财政支农水平在农业生态治理阶段有正向影响。  相似文献   

10.
湖北省农地利用碳排放时空特征与脱钩弹性研究   总被引:9,自引:0,他引:9  
基于化肥、农药、农膜、农用柴油、翻耕、稻田6个主要方面的碳源,测算了湖北省1995~2009年及其地、市、州2008年的农地利用碳排放量。结果表明:(1)自1995年以来,湖北农地利用碳排量总体呈现“上升-下降-上升”的三阶段特征,其碳排放强度变化轨迹与此基本一致。(2)区域差异明显:农地碳排放总量,江汉平原、鄂东北地区高,鄂西、鄂东南地区较低;农地碳排放强度,总体呈现东高西低的特征,即鄂东>鄂中>鄂西。进一步运用Tapio脱钩模型对湖北省农地利用碳排放与农业经济发展间的脱钩关系进行了研究,发现以弱脱钩和强脱钩为主,可见近些年来农地利用碳减排取得了一定成效  相似文献   

11.
Integration of indigenous knowledge and ethnoscientific approaches into contemporary frameworks for conservation and sustainable management of natural resources will become increasingly important in policies on an international and national level, both in countries that are industrialised and those that have a developing status. We set the scene on how this can be done by exploring the key conditions and dimensions of a dialogue between ȁ8ontologiesȁ9 and the roles, which ethnosciences could play in this process. First, the roles of ethnosciences in the context of sustainable development were analysed, placing emphasis on the implications arising when western sciences aspire to relate to indigenous forms of␣knowledge. Secondly, the contributions of ethnosciences to such an ȁ8inter- ontological dialogueȁ9 were explored, based on an ethnoecological study of the encounter of sciences and indigenous knowledge in the Andes of Bolivia, and reviewed experiences from mangrove systems in Kenya, India and Sri Lanka, and from case-studies in other ecosystems world-wide, incl. Australia, Burkina Faso, Ecuador, Ethiopia, Guatemala, Indonesia, Nepal, Niger, Philippines, Senegal, South-Africa and Tanzania.  相似文献   

12.
We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.  相似文献   

13.
Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999-2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.  相似文献   

14.
The Eastern Mediterranean region is among the regions which were predicted to become drier under IPCC climate scenarios. Here, we document a gradual reduction of rainfall and tree growth and the loss of rural springs during the last decades of the twentieth century. Years with severe drought are associated with very low tree growth (dendrochronology) and dry falling of springs as evidenced by interviews with local stakeholders. The paper discusses the consequences of accelerating drought on natural vegetation and agriculture and points at the interaction with fire dynamics and economy, both likely to enhance the drought effect.  相似文献   

15.
The effect of long-term exposure to natural excretions of the European polecat on the morphological parameters and hormonal status of adult male Campbell hamsters (Phodopus campbelli) and dwarf hamsters (Ph. sungorus) was studied. Exposure to volatile components of natural excreta of a potential predator did not have any significant effect on hamsters. The combined influence of volatile and nonvolatile components of the polecat’s excretions caused physiological stress in Ph. campbelli, while in Ph. sungorus, on the contrary, an increase in thymus weight and the plasma testosterone level was recorded.  相似文献   

16.
The use of experimental settings to observe human behaviour in a controlled environment of incentives, rules and institutions, has been widely used by the behavioural sciences for sometime now, particularly by psychology and economics. In most cases the subjects are college students recruited for one to two hour decision making exercises in which, depending on their choices, they earn cash averaging US$ 20. In such exercises players face a set of feasible actions, rules and incentives (payoffs) involving different forms of social exchange with other people, and that in most cases involve some kind of externalities with incomplete contracts, such as in the case of common-pool resources situations. Depending on the ecological and institutional settings, the resource users face a set of feasible levels of extraction, a set of rules regarding the control or monitoring of individual use, and sometimes ways of imposing material or non-material costs or rewards to those breaking or following the rules. We brought the experimental lab to the field and invited about two hundred users of natural resources in three Colombian rural villages to participate in such decision making exercises and through these and other research instruments we learned about the ways they solve - or fail to - tragedies of the commons with different social institutions. Further, bringing the lab to the field allowed us to explore some of the limitations of existing models about human behaviour and its consequences for designing policies for conserving ecosystems and improving social welfare.  相似文献   

17.
Databases have been compiled to derive parameter values relevant to the transfer of radionuclides from feedstuffs to domestic animal products to provide a revision to the IAEA Handbook on transfer parameters TRS 364. Significant new data inputs have been incorporated into the databases from an extensive review of Russian language information and inclusion of data published since the early 1990s. Fractional gastrointestinal absorption in adult ruminants presented in the revised handbook are generally similar to those recommended for adult humans by the ICRP. Transfer coefficient values are presented in the handbook for a range of radionuclides to farm animal products. For most animal products, transfer coefficient values for elements additional to those in TRS 364 are provided although many data gaps remain. Transfer coefficients generally vary between species with larger species having lower values than smaller species. It has been suggested that the difference is partly due to the inclusion of dietary dry matter intake in the estimation of transfer coefficient and that whilst dietary intake increases with size nutrient concentrations do not. An alternative approach to quantifying transfer by using concentration ratios (CR), which do not consider dietary intake, has been evaluated. CR values compiled for the handbook vary considerably less between species than transfer coefficient values. The advantage of the CR approach is that values derived for one species could be applied to species for which there are no data. However, transfer coefficients will continue to be used as few studies currently report CR values or give data from which they can be estimated.  相似文献   

18.
A dynamic model of radionuclide accumulation in fish is developed. In the model, the fish population is represented by a set of discrete age classes. Each age class is characterized by a specific growth rate, diet and activity of metabolic processes. The model describes all known types of size effect in the contamination of fish with radiocaesium. The detailed dynamics of 137Cs accumulation by fish are demonstrated using the results of the model's application to ichtiofauna in a water body which has a high level of contamination with radiocaesium — namely, the cooling pond of the Chernobyl NPP.  相似文献   

19.
ABSTRACT

Formula 1 motor sport and the Men's World Cup of association football, two major sporting events on our calendars, are indirectly and directly responsible for environmental despoliation. They serve as advertisements for heavy industry, are designed for elite as much as mass consumption, and provide sponsors with dubious social licenses to operate. This occurs through the very mechanisms of the events themselves (engines in Formula 1, tourism in the World Cup) as well as their promotional externalities. I look at greenwashing claims made about these two sporting events and examine counter-discourses, then investigate economic and ecological citizenship. I suggest that a progressive agenda can be forwarded if Greenpeace, which runs campaigns related to these sports, works with its fellow elites, in the case of Formula 1, and with fans in the case of football. Doing so may be more effective than business-as-usual direct action.  相似文献   

20.
江苏海洋开发的资源环境条件评述   总被引:4,自引:0,他引:4  
江苏海洋的区位优越,海域广阔,环境条件总体有利,海洋资源种类多,数量大,具有综合开发功能,而且资源和环境的区域组合良好,有利于海洋产业的集约经营和协调发展,但也存在不少限制因素,如深水区离岸较远,海底矿产勘探程度低,自然灾害较多等。应根据实际情况确定本省海洋的开发战略。  相似文献   

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