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91.
刘士清 《中国环境管理干部学院学报》2013,(1):8-10,34
为推进企业环境保护信用等级管理,滨州市环保和监察部门联合制定工作方案并向所辖县区下发文件专门部署,结合日常执法监管对市控以上企业从环保专项行动、排污情况、污染事故、治污设施、排污费和行政处罚、环境安全、建设项目、环境信访八个方面综合评定信用等级,实施有针对性的环境监督管理,有效解决了执法成本高、执法人员不足的问题,使有限的执法资源得到最合理的优化配置,进一步规范了企业环境行为,实现了引导企业自主守法和提高执法效率的双赢。 相似文献
92.
基于非参数方法的中国棉花产出规模效率时空特征 总被引:2,自引:0,他引:2
人类需要的无限性和用来满足需要的各种稀缺资源之间的矛盾,要求人们对生产资源进行有效配置。为研究中国棉花流通体制市场化改革以来,棉花生产资源的配置效率--产出规模效率及其时空特征,基于生产前沿面理论的非参数方法,利用生产资源配置效率测度软件对中国棉花主产区的棉花产出规模效率进行了具体测定与分析。结果表明:中国棉花产出规模效率时空差异显著,报告期长江流域优于黄河流域,同时两大流域棉花产出规模效率变化态势与我国棉花流通体制市场化改革的政策安排高度相关。认为中央政府应根据市场化进程中棉花生产所表现出来的新特点与市场调节出现的新问题,适时做出进一步激励棉花生产,最大程度发挥产出规模效率的政策安排。 相似文献
93.
This paper analyzes the three main fundamental issues in the design of China’s ETS pilots,including allowance allocation,price mechanism and state-owned key enterprises,and proposed suggested solutions.For the issue of allowance allocation,we suggest that the gradual hybrid mode could be applied at the beginning,which starts with mainly free allocation and then increases auction ratio gradually.And grandfathering is a suitable method of free allocation.For the issue of price mechanism,we suggest a price floating zone with open market operation to reduce the uncertainty of prices.For the issue of state-owned key enterprises,we suggest a good coordination with SASAC,defining the state-owned property right and supervision right when state-owned key enterprises are involved into the carbon market,and the local government can set rules of allocation and transaction to limit their potential market power. 相似文献
94.
Increasing difficulties associated with balancing consumptive demands for water and achieving ecological benefits in aquatic ecosystems provide opportunities for new ecosystem-scale ecological response models to assist managers. Using an Australian estuary as a case study, we developed a novel approach to create a data-derived state-and-transition model. The model identifies suites of co-occurring birds, fish, benthic invertebrates and aquatic macrophytes (as ‘states’) and the changing physico-chemical conditions that are associated with each (‘transitions’). The approach first used cluster analysis to identify sets of co-occurring biota. Differences in the physico-chemical data associated with each state were identified using classification trees, with the biotic distinctness of the resultant statistical model tested using analysis of similarities. The predictive capacity of the model was tested using new cases. Two models were created using different time-steps (annual and quarterly) and then combined to capture both longer-term trends and more-recent declines in ecological condition. We identified eight ecosystem states that were differentiated by a mix of water-quantity and water-quality variables. Each ecosystem state represented a distinct biotic assemblage under well-defined physico-chemical conditions. Two ‘basins of attraction’ were identified, with four tidally-influenced states, and another four independent of tidal influence. Within each basin, states described a continuum of relative health, manifest through declining taxonomic diversity and abundances. The main threshold determining relative health was whether freshwater flows had occurred in the region during the previous 339 days. Canonical analyses of principal coordinates tested the predictive capacity of the model and demonstrated that the variance in the environmental data set was well captured (87%) with 52% of the variance in the biological data set also captured. The latter increased to >80% when long- and short-term biological data were analysed separately, indicating that the model described the available data for the Coorong well. This approach thus created a data-derived, multivariate model, where neither states nor transitions were determined a priori. The approach did not over-fit the data, was robust to patchy or missing data, the choice of initial clustering technique and random errors in the biological data set, and was well-received by local natural resource managers. However, the model did not capture causal relationships and requires additional testing, particularly during future episodes of ecological recovery. The approach shows significant promise for simplifying management definitions of ecological condition and, via scenario analyses, can be used to assist in manager decision-making of large, complex aquatic ecosystems in the future. 相似文献
95.
William J.M. Probert Martin DrechslerPeter W.J. Baxter Hugh P. Possingham 《Ecological modelling》2011,222(10):1781-1789
It is becoming increasingly popular to consider species interactions when managing ecological foodwebs. Such an approach is useful in determining how management can affect multiple species, with either beneficial or detrimental consequences. Identifying such actions is particularly valuable in the context of conservation decision making as funding is severely limited. This paper outlines a new approach that simplifies the resource allocation problem in a two species system for a range of species interactions: independent, mutualism, predator-prey, and competitive exclusion. We assume that both species are endangered and we do not account for decisions over time. We find that optimal funding allocation is to the conservation of the species with the highest marginal gain in expected probability of survival and that, across all except mutualist interaction types, optimal conservation funding allocation differs between species. Loss in efficiency from ignoring species interactions was most severe in predator-prey systems. The funding problem we address, where an ecosystem includes multiple threatened species, will only become more commonplace as increasing numbers of species worldwide become threatened. 相似文献
96.
提出用与碳排放“同步变化程度”来衡量配额指标重要性的思想,对中国各省份碳排放配额进行再分配.首先在公平和效率原则基础上选取碳排放的影响因素作为分配指标,其次采用灰色关联分析法分别测算出各地区各指标与碳排放量的同步变动程度,以得到各地区各指标在配额分配中的比重.最后测算出我国29个省区2020~2030年的碳排放配额与排放空间.结果表明,人口基数及经济发展指标对各地碳排放有较强的同步变动关联性,因此应该被赋予更高的权重;配额最多的地区包括广东、北京、江苏、山东、上海,最少的地区则包括宁夏、贵州、青海、吉林、新疆.盈余分析发现,北京地区的碳排放空间有较多盈余;浙江等5个省区已达较饱和状态;山东等4个省区则处于较严重的溢出状态,在未来10年内需承担较重的减排压力. 相似文献
97.
Pheromone-based female mate choice and its effect on reproductive investment in a spitting spider 总被引:1,自引:0,他引:1
Teck Hui Koh Wee Khee Seah Laura-Marie Y. L. Yap Daiqin Li 《Behavioral ecology and sociobiology》2009,63(6):923-930
Numerous studies have focused on whether organisms can signal or perceive pheromones and use chemical signals in species and
mate recognition. Recently, there have been an increasing number of studies investigating whether pheromones are used in mate
choice. Yet, little attention has been paid in exploring the effects of pheromone-based mate choice on reproductive investment.
We first tested this hypothesis by providing virgin Scytodes sp. females with a choice between two virgin males in the presence of chemical signals alone and found strong evidence of
an odor-based mate preference. We then examined the consequences of the odor-based mate choice by allowing female Scytodes sp. that had previously made an odor-only mate choice to mate with preferred and non-preferred males, respectively. We measured
the success of copulation, mortality of male, pre-oviposition interval, egg-sac weight, egg weight, fecundity, fertility,
embryonic period, and size of offspring at hatching. Females that mated with the preferred males produced significantly heavier
egg sacs that contained more and larger eggs with a greater fertility. Significantly more non-preferred males than preferred
males were killed by spitting. However, pre-oviposition interval, embryonic period, and hatchling size were not affected by
female mate choice. This study is the first to demonstrate that female spiders are able to regulate their highly valuable
reproductive investment based solely on chemical signals. 相似文献
98.
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100.
Optimal biomass allocation in heterogeneous environments in a clonal plant—Spatial division of labor
When interconnected ramets of clonal plants are growing in heterogeneous environments, ramets may specialize to uptake locally abundant resources rather than scarce resources. This biomass allocation pattern may result in more efficient sharing of resources through physiological integration and an overall benefit to the plants (spatial division of labor; DoL). 相似文献