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1.
A comparative analysis of field observations and experiments on the distance and rate of dispersal of self-sown Scotch pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) progeny has shown that the rate of their hydrochorous dissemination downstream is an order of magnitude higher than the rate of dispersal in upland areas. A hypothesis assigning priority to the role of hydrochory in the expansion of conifer populations to the tundra (periglacial) zone along with climate warming has been formulated and substantiated by comparative isozyme analysis of populations in transects lying along and across rivers.  相似文献   

2.
In the crustacean Eudiaptomus gracilisSars, relationships between mortality (D) and the ratio of main cations (R, the ratio of the sum of potassium and sodium equivalent concentrations to the sum of calcium and magnesium equivalent concentrations) were studied. The calculated regression equation D= 315 – 355/Rwas used for predicting the state of E. gracilispopulation in Lake Poppalijarvi (Karelia) polluted with mining waste. At R< 0.47, the population will survive; at R> 1.53, its extinction should be expected. The results of hydrobiological observations on Lake Poppalijarvi confirmed the prognosis based on the equation.  相似文献   

3.
以加入WTO为标志.中国积极参与经济全球化已成为一种必然.但由于我国的国土规模、自然环境、气候条件等方面的地区差异很大,地区之间在发展水平上一直存在着差距,地区发展不平衡是个长期的国内政治经济现象.这种地区发展的差距表现为各类地区融入经济全球化的程度不同,反应不同.有些地区能够借助经济的全球化而发展自身,有些地区则无法从中受益,甚至因而处于更加落后的境地.本文从三大经济地带、各经济区和各省(市)区三个屡次分析和探讨了不同区域对经济全球化响应的差异,并对全球化条件下我国内部区域一体化格局进行了深入的研究.  相似文献   

4.
地质旅游研究进展   总被引:1,自引:0,他引:1  
自20世纪70年代以来,地质旅游受到世界各国的重视,并在国内外相关领域的研究中积累了丰富的经验和文献。本文从地质旅游的含义、地质旅游活动发展历程和国内外理论与实践建设出发对地质旅游进行归纳和总结。综述表明,地质旅游越来越受到游客、地方和政府的关注和重视,是一重要的生态和可持续旅游型式。  相似文献   

5.
Studies on the distribution of the forms of heavy metals (HMs) in the humus soil horizon were performed in the Berezinskii Reserve and Braslavskie Ozera National Park. The ratios of active to inert HM forms (with trace values of the mobile form) in these areas proved to be similar and independent of the total HM content. The calculated coefficients of technogeneity (Kt and Xt) and mobility (Km and Xm) are proposed, which reflect the natural ratio between the forms of HMs in the Northern and Central lithogeochemical provinces of Belarus.  相似文献   

6.
退耕还林工程费用有效性的影响因素分析   总被引:3,自引:0,他引:3  
费用有效性评价是工程评价的重要方面。从政策制定和执行角度对退耕还林的费用有效性及其影响因素进行分析。具有重要的意义。利用实地调研数据和相关统计数据.从退耕地选择和造林入手对退耕还林工程实施的费用有效性殛其影响因素进行考察.并尝试对这些因素的作用机制进行了分析。研究指出由于缺乏长期的和有效的退耕还林规划以及相关政策措施的缺失.使得退耕还林费用有效性的损失在微观层面和宏观层面广泛存在。而各利益主体的利益不相害性是影响工程有效实施的基本矛盾。有必要在遇耕还林中确立明确的规划、清晰的退耕地选择标准。建立和完善管理信息系统和及时有效的反馈和控制机制。构建协调多方利益的长期稳定的生态补偿机制。从而改进退耕还林工程的费用有效性。  相似文献   

7.
实施生态补偿制度是保障黄河三角洲高效生态区可持续发展的基础。该文在明晰黄河三角洲高效生态区生态补偿原则和利益相关方各自的责任和义务的基础上,提出并设计了黄河三角洲高效生态区生态补偿平台建设思路和生态补偿运行机制。生态补偿平台建设主要包括:建立由政府主导的生态补偿交易市场平台;建立以生态补偿保险、生态补偿期货、互助基金、证券化交易为主要内容的生态补偿风险保障平台;建立以相关独立认证和监测(检测)、资产评估、审计、代理等机构组成的生态补偿交易中介服务平台;建立生态补偿监管平台。生态补偿运行机制需要将法制建设、财政扶持、税收调节和保障措施等系统化:推进《生态补偿法》、《黄河三角洲高效生态区补偿协定》的制定;完善并建立中央财政转移支付、财政转移制度纵向化、"环境财政"等制度;改革创新区域或专项税收制度;构建完备的生态补偿评估、考核、监督管理体系,等等。  相似文献   

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9.
The results of the census of stray dogs and data on their territorial distribution in the city of Petrozavodsk are reported. The population density of these animals has been found to vary within the urban area, depending mainly on the availability of secluded areas to live in and on population control by municipal services.  相似文献   

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11.
The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased  相似文献   

12.
作为当代环境伦理学之生态中心论的代表,克里考特以新物理学与生态学的视角引向后现代主义的整体观。这一思路指向的是整体论系统观的范式,后者具有四项特征:1整体的性质不能被还原为部分的性质;2整体是部分形成的原因与依据;3部分是系统地互相联系的;4部分是内在地互相联系的,即关系决定存在。以该整体论系统观的范式为依据,克里考特的后现代视域既涉及本体论,也指向价值论。在本体层面,克里考特借鉴了深生态学中"充分实现的自我"的概念试图解构笛卡尔的主客二分。进而,在削弱现代哲学中三类性质(数量性、质量性与价值性)区分的同时,克里考特提出了"实质价值"的概念,并试图以实质价值消解内在价值的同时统摄固有价值与工具价值。在文本梳理的基础上,本文也考察了克里考特的后现代视域的逻辑依据与实践可能。具体地,本文指出:1克里考特以实证科学之认知来架构形上本体的思路混淆了科学命题与玄学命题的区别内涵;2建立在消解三类性质基础上的"实质价值"架空了价值本身的应然引力;3克里考特过分地强调了整体与部分的对立从而容易陷入逻辑悖论;4克里考特以关系消解实体的本质是将关系作了唯内在性的理解,而这种理解是缺乏支持力的。特别地,克里考特以整体解析部分并以关系消解个体的进路将导致伦理虚无主义。针对克里考特理论的缺陷,本文指出,以"关系"为纽结的部分与整体之间是体用统一的;而实体间的关系,既具有内在性的一面,也具有外在性的一面;并且,关系的外在性既具有本然的维度,也具有应然的维度,即,它是道德实践的必要前提。  相似文献   

13.
从社会排斥的视角分析中国公众环境权益的缺失   总被引:1,自引:0,他引:1  
社会排斥是近年来社会学研究中的重要概念。本文在对社会排斥内涵进行简要述评的基础上.探讨将这一独特视角用于公众环境权益诠释的可能性,并具体分析中国公众在环境权益实现过程中所面临的社会文化排斥、社会体制排斥、自我认同排斥等社会排斥现象及其三者之间的关系。公众在环境权益实现中所遇到的社会排斥包括两个方面:一是由消极排斥到积极排斥再到消极排斥的作用与反作用过程;二是自为排斥与自在排斥相互交错融合的过程。消除各种社会排斥的可行对策是:建立公众参与环境制度.促进环境NGO发展,强化环保执法能力.推动环保机制从政府主导型向社会制衡型转变。  相似文献   

14.
The risk communication (RC) field is dominated by the practical and normative socio-technical aim of improving communication on risk (CR), especially from the viewpoint of regulatory agencies and government administrations. Despite some change of scope and orientation over the past 30 years, two theoretical ideas have persisted: the subjective–objective risk dichotomy and the transmission (also known as code) model of communication. This theoretical legacy makes context a blind spot in RC. The study of CR themes should consider (1) the socially constructed nature of risk and (2) communication as a situated social practice of information sharing. Results of a case study of public participation in a controversial railway tunnel project in the south of Sweden, offer lessons for future research pointing to crucial contextual dimensions of CR. It is argued that the variable ontology of risk, the constitutive nature of power relationships and the practical rationality of actors must be taken into account in research on the social CR.  相似文献   

15.
凤凰城旅游景区转让后的效应评价   总被引:7,自引:0,他引:7  
在我国经济市场化改革的大背景下,转让景区经营权、实行企业化运作成为一些风景名胜区经营管理改革过程中的一种制度创新模式。地处西部大开发战略图中的湘西凤凰县由于在旅游开发中受到了资金缺口和管理瓶颈的双重制约,于2001年底将其辖域内的八大景区(点)的50年经营权转让给了湖南黄龙洞投资股份有限公司。景区经营权转让是一个十分复杂而敏感的话题。本文避开关于景区经营权转让的各种是非争论,基于对旅游地社区各利益主体以及旅游者的实地调查和访谈记录分析,对凤凰景区企业化运作三年来的绩效与影响作了较为客观的评估,并就如何完善景区企业化运作模式、规避经营管理风险和负面影响等提出了相关理论思考和政策建议。  相似文献   

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17.
The article establishes an evaluation index system of the intensive land use from the perspective of enterprises. It is based on the questionnaire survey and evaluates the levels of the intensive use of the land in the electrical machinery and equipment manufacturing industry in Changzhou, Nantong, and Yancheng of Jiangsu Province. The evaluation result shows that there is obvious difference in the levels of the intensive use of the land in this industry in the three cities. The present article makes a detailed analysis on the causes of the difference. The analysis shows difference in results of the socio-economic and urban development stage, industrial features, population density, and technological progress. Finally, it proposes some suggestions to improve the efficiency of the industrial land use.  相似文献   

18.
19.
The effect of flavonoids, natural plant metabolites, on the growth and viability of enterobacteria was studied using S. typhimurium and E. coli strains defective in some components of the DNA repair system. The minimal inhibitory concentrations of several flavonoids were measured. These agents were shown to have a weak bactericidal and a marked bacteriostatic effect, the latter increasing under anaerobic conditions. It is proposed that the mechanism of the bacteriostatic action of flavonoids is based on topoisomerase II inhibition. On the basis of these results, the ability of flavonoids to differentially suppress bacterial growth and their probable influence on the ecology of microorganisms (the formation, species composition, and ecological balance of natural microbial communities) are discussed.  相似文献   

20.
The phenomenon of bottom substrate exposure in deeply freezing lakes during the melting of ice in spring is described. It leads to the formation in the lake of a large temporary biotope—a combination of shoals and exposed portions of the silty bed—with a high trophic capacity for ducks, shorebirds, gulls, etc. The lake in such a state is a rich foraging area for nesting and migrating bird populations. This phenomenon, which is widespread in the Central Yakutian plain, is an ecological manifestation of cryoarid conditions developing in the plains due to extreme climate continentality.  相似文献   

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