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1.
Two alternative ontogenetic pathways regularly effected in the populations of small mammals are analyzed as a manifestation of developmental multiversality. The types of ontogeny in rodents are characterized. These data are reflected in the concept of the functional approach. Multiversality of development in plants and animals is considered. Based on the results of long-term (26-year) observations on the natural populations of six rodent species, the dynamics of relationships between the types of ontogeny, abundance, and basic population parameters are analyzed using an example of a background species (Clethrionomys glareolus). A trigger mechanism of switching to a certain type of ontogeny, the role of environmental factors in actuating this mechanism, and the role of the genotype as a basis of multivalence are discussed. The existence of two developmental variants is regarded as a basis for functional rearrangements providing for a high flexibility of population responses and as a mechanism of population regulation determining the dynamics of rodent fauna. An adaptive population response to a board spectrum of influences, including anthropogenic damage, depends not only on the type and strength of the influence, but also on the functional structure of the population. The concepts described in the paper may explain the significance of critical periods in the life of populations.  相似文献   

2.
Experience in organizing a natural reference area (standard) for studies on the functional dynamics of ecosystems in connection with paludification and forest-bog relationships is described. The essence of studies on ecosystem dynamics with the aid of natural standards and key plots is described using an example of the Yenisei region of Western Siberia. Arguments are presented for the necessity of using a differential approach to studies on the dynamics of nature and taking into account local ecological conditions while extrapolating the results of these studies to other geographic regions.  相似文献   

3.
环境规制对企业竞争力的影响   总被引:17,自引:0,他引:17  
除改进环境源效外.环境规恻对本国企业竟争力的影响也是政策恻定的关键影响因素。传统假设认为环境规铆会负面影响企业竞争力。波特假设认为在一定条件下。环境规制通过创新补偿与先动优势可提高企业竟争力。本文在提出问题的基础上,对上逮假设进行了剖析。然后讨论了该领域研究的新动向.即不确定性因素的存在对环境规恻与企业竟争力关采的影响。提出环境规制能否影响企业的竟争力还依赖于企业面临的内外部条件、环境管理动机等多种因素。  相似文献   

4.
Data are presented on the abundance, structure, and dynamics of hemipopulations of G. conopsea protocorms and autotrophic individuals at the northern boundary of the species range. The dynamics of ontogenetic structure of G. conopsea cenopopulations have a fluctuating pattern. Their response to adverse weather conditions is manifested in short-term reduction of density and increase in cenopopulation ageness in subsequent years. Deterioration of growing conditions in a series of ecotopes is accompanied by an increase in the proportion of young individuals, which allows the species to level off the impact of adverse weather factors on population size.  相似文献   

5.
气候变化已成为不争的事实.减缓和适应是人类应对气候变化的两类主要措施,在气候变化减缓行动难以很快奏效的情形下,采取具有针对性的适应战略已经成为世界各国更为紧迫的选择.一个有效的适应行动机制需要全社会的广泛参与,而公众和决策层对气候变化的认知是适应行动机制的形成基础.本文以银川阅海湿地适应气候变化能力建设为研究案例,从政府部门和社会公众两个层次进行讨论,比较其对气候变化的认知程度及其对适应措施的评价和需求,以期对适应气候变化策略的认知基础研究提供依据.研究结果表明,无论社会公众和决策层,适应气候变化的意识基础均已基本形成,但公众的认知基础要弱于决策层,并且在认知的准确程度上低于决策层;公众和决策层对气候变化适应政策的实施都做出了正面的评价,但决策层的评价普遍显著高于公众;对于适应政策的需求,公众的政策需求主要集中在公共服务方面,而决策层的适应策略是多方位的,也包括通过限制个人行为来获得公共利益.  相似文献   

6.
Fuelwood is one of the major sources of energy in the domestic sector across the rural areas,especially in the developing regions across the world.The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area.The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region,thus indicating the livelihood conditions.Since land-use land-cover change is the key driver to the change in resource availability of a region,the present study has tried to analyze the landcover changes over a period 28 years.The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics,which directly affect the resource production.Based on the existing consumption pattern,the total consumption of fuelwood in the watershed ranges fiom a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year.Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system.  相似文献   

7.
中国地区间跨界污染治理的两阶段多边补偿机制研究   总被引:1,自引:0,他引:1  
近年来,以雾霾、河流污染等为代表的跨界污染问题严重影响了我国经济社会的可持续协调发展。本文将跨界污染治理视为典型的地区间外溢性公共品,从公共经济学的视角出发,分析了我国地区间跨界污染治理的种种困境,并通过构建两阶段多边博弈模型,探讨了补偿机制的可行性。本文首先构建了一个跨地区的污染模型,通过中央政府干预或不干预的博弈分析发现,当污染存在地区内部及跨地区的外溢性时,如果中央政府不介入而由企业自行设定产出水平,那么企业的污染排放水平将超过社会有效率的水平。在此基础上,本文进一步构建了一个两阶段多边补偿机制博弈模型,即由中央政府设计一个地区内部企业与居民之间以及跨地区之间的补偿机制,来解决以上的无效性问题。结果显示,当企业支付的补偿金额取决于居民设定的补偿系数,而居民得到的补偿金额又取决于企业设定的补偿系数时,相互影响的博弈关系使得企业和居民从自身的利益出发,将补偿系数设定在企业污染对于居民边际损害的水平,从而企业生产水平会达到有效状态,两阶段多边补偿机制实现了有效的污染排放。本文在庇古税思想的基础上,通过放松庇古税对外部性相关信息的强假设,构建了一个两阶段多边补偿机制,即由企业缴纳庇古税后,中央将征收的庇古税补偿给居民,这样不仅内部化了企业污染给居民造成的负外部性,还进一步平衡了地区间的跨界污染治理问题。  相似文献   

8.
Communities of benthic macroinvertebrates in drainless Lake Chany, the largest lake in Western Siberia, have been analyzed to estimate the effects of basic abiotic ecological factors (hydrophysical and hydrochemical parameters of water and the type of bottom ground) on their composition, structure, and dynamics. It has been shown that the level of development of these communities depends mainly on the water regime of the lake and also on the type of bottom ground, lake depth, and water mineral content.  相似文献   

9.
Four introduced and one aboriginal species of the genus Pinus L. have been studied in the middle taiga subzone of southern Karelia. Significant interspecific differences in the dates of onset, cessation, and peak of the growth of shoots and needles have been revealed. It has been shown that their annual increment depends on the rate of growth, rather than on its duration. The dynamics of shoot and needle growth in introduced and aboriginal species, though largely similar, differ in some respects. These differences reflect species-specific responses to hydrothermal conditions in a certain growing season.  相似文献   

10.
Fuelwood is one of the major sources of energy in the domestic sector across the rural areas, especially in the developing regions across the world. The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area. The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region, thus indicating the livelihood conditions. Since land-use land-cover change is the key driver to the change in resource availability of a region, the present study has tried to analyze the land-cover changes over a period 28 years. The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics, which directly affect the resource production. Based on the existing consumption pattern, the total consumption of fuelwood in the watershed ranges from a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year. Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system.  相似文献   

11.
The influence of the water level in the period of the open river channel and the duration of lower floodplain inundation on the feeding conditions, abundance, and population state of coregonids in the Lower Ob was investigated. The long-term dynamics of catches of some coregonid species was analyzed and compared with changes in the hydrologic conditions in the floodplain. The relationship between basic hydrologic conditions in the Lower Ob (water level in the period of the open channel, the duration of the lower floodplain inundation), the coregonid population sizes, the state of spawners, and the size of catches is demonstrated.  相似文献   

12.
Variation in radial increments of 28-year-old Pinus sylvestris L. clones in response to changes in weather conditions during the period between 1986 and 2007 has been studied in the Sredneobskii Bor pine forest. Significant genotypic differences in the adaptive reaction norm of the clones have been revealed. It has been shown that the contribution of genotypic differences to the total variance of test characters is usually significant and depends both on the conditions of growing season and on a given increment character.  相似文献   

13.
The small-rodent populations of five collective gardens have been studied. The example of one of the populations has been used to monitor the annual cycle of population size. The species composition and animal number depends on the biotope, climatic conditions, and the anthropogenic load. The ratios between species in the gardens and neighboring biotopes differ from each other, with different species being dominant. It is assumed that small mammals use garden plots as refugia.  相似文献   

14.
环境-社会系统的三元结构是指人、社会和自然三元。可持续发展取决于对这三元运动机制的协调。从环境-社会系统的视角看。可持续发展是指通过三种生产的和谐运行与环境—社会系统的稳定演进.获得“经济-社会-环境”整体的高效益。人类社会发展的两大基本矛盾是资源生产的矛盾和资源配置的矛盾.因此。建设和谐社会的关键在于:在争取“人-社会-自然”和谐演进的前提下。处理好人与社会、人与自然、自然与社会以及自然的、社会的方方面面的“关系”。  相似文献   

15.
岷江上游地区在我国长江上游同山峡谷区代表性,由于近几十年来人为活动加剧,该区生态系统严重退化。简要介绍了岷上游山地生态系统的概况,讨论了关键种群在退化生态系统研究中的作用和意义。在此基础上进一步认为,岷江上游山地系统退化机理研究应以典型的干旱河谷灌丛,亚高山森林和亚高山草甸等主要生态为对象,以关键种群为核心和切入点,重点研究了干旱河谷批示植物种群动态有其与环境退化的关系、主要动植物种群在变化在草地生态系统退化过程中的作用、亚高山关键种苗木定居及对退化产生理生态适应机制、土壤微生物区系变化有其对系统中氮素归还的影响等,进而有助于在理论上阐述关键种群的生态功能,探讨关键种群变化导致生态系统退化的作用机理;在实践上为目前国家实施西部大开发生态环境建设的重大需求提供理论依据,推动恢复生态学的发展和该区域的生态建设。  相似文献   

16.
忽视了地理位置因素的传统统计分析方法无法真正反映经济要素空间差异的动态演变过程,经验贝叶斯修正的空间自相关指数有效地避免了方差不稳定性,为泛长江三角洲区域经济空间差异的定量分析提供了有力支撑。借助经验贝叶斯修正的空间自相关指数,对1999~2008年泛长江三角洲区域经济发展的总体空间差异、集聚中心和孤立点的空间转移路径以及局部空间差异进行探索性分析。研究结果表明:总体上,经济发展在泛长江三角洲区域具有较好的空间结构性和空间关联性,全局空间自相关指数呈现出波动性增大趋势;经济集聚中心和孤立点的空间转移路径存在一定的规律性,表现为传统长江三角洲地区始终作为高值集聚中心,安徽始终作为低值集聚中心,南昌始终作为高值孤立点,泰州始终作为低值孤立点;从局部来看,区域经济发展表现出十分明显的局部空间差异,表现为传统长江三角洲地区的高值指向性与新扩容省份的低值指向性  相似文献   

17.
The effect of climatic conditions on the dynamics of 21 populations of 10 species of the family Orchidaceae at the northern limit of their range in Europe was studied between 1992 and 2004. The abundance of orchid populations proved to depend primarily on air temperature during the previous and current growing seasons.  相似文献   

18.
The dynamics of food chains upon changes in water salinity has been analyzed using the example of six poly- and hyperhaline lakes in the Crimea. The results show that ecosystems of saline lakes are sensitive to the impact of external factors. Changes in weather conditions often lead to fluctuations of water salinity, which may cause a changeover in the hydrobiological regime of the lake. In lakes with high water salinity, the shortening of food chain takes place, and the cascade effect is observed in their dynamics.  相似文献   

19.
Validation of the CANDY model with Russian long-term experiments   总被引:1,自引:1,他引:0  
The CANDY model has been qualitatively assessed for simulating long-term dynamics of soil organic carbon and tested against different long-term experiments representing various land uses and geographical sites, but never before against conditions of the Former Soviet Union (FSU). Our goal was to simulate long-term trends in soil organic carbon for the long-term experiments of Barybino (Moscow region, Russia), Grakov (Kharkow region, Ukraine) and Yachenka (Minsk region, Belarus) representing the predominant arable soil types, climate conditions and typical management strategies for the investigated arable areas. The fit of modelled results to the observed data was evaluated to assess the suitability of the model for further applications in the FSU. The crop parameters of the CANDY model had to be adapted to the low yields observed under the Russian site conditions resulting in a higher sensitivity to crop-derived carbon input as a function of yield. The results show that the approach of treating the organic carbon situated in micro pores as inert, is an applicable solution for simulating soil carbon dynamics under Russian conditions. This evaluation of CANDY, against long-term experiments from Russia, gives confidence for its wider application in this region.  相似文献   

20.
Consideration is given to the results of studies on the postfire dynamics of Transbaikal forests, which are formed under conditions of highly arid climate and extreme pyrological regime. Data are presented on tree die-off and recruitment in naturally burned forests and in test stands affected by creeping fires differing in intensity. The hydrothermal regime of soils, precipitation runoff, and its multifactor models are discussed. It is shown that fires aggravate moisture deficiency on mountain slopes, impair the productivity of tree stands, and cause their digression. The statistics of forest fires and the risk of lightning fires are analyzed.  相似文献   

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