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61.
62.
出境旅游热的"冷"思考——从我国出境旅游者不文明行为谈起 总被引:1,自引:0,他引:1
近年来,我国出境旅游出现了一股热潮,社会给予了极大的关注。但是,随着出境旅游者人数的日益增多,他们在旅外途中做出“不文明”行为的现象也越来越频繁。对于这些“不文明”行为给我国带来的负面影响,旅游学界讨论得很少,业界似乎也没有给予足够的重视。在梳理此类行为表象的基础上,由现象到本质初步探讨了这些“不文明”行为可能造成的负面影响,并据此提出了一些对策建议。 相似文献
63.
Trail erosion patterns in Great Smoky Mountains National Park 总被引:3,自引:0,他引:3
All the maintained trails in Great Smoky Mountains National Park were surveyed for width, depth, and a variety of types of erosion. Trail erosion is related to a number of environmental variables, including vegetation type, elevation, trail slope, and section of the park. Open grass balds and spruce-fir forest are the most erosion-sensitive plant communities, and the xeric oak and pine types are the least sensitive. Trails in virgin or mature forest tend to be in poorer condition than those in successional areas. The most important physical factor is the slope of the trail.Trails in the Tennessee district are in slightly poorer condition, on the average, than those in the North Carolina district, but the Appalachian Trail is more eroded than either. A poor section of the park may have ten times the erosion of a good section. On an allpark basis, water erosion is the most important problem, with 15% of the trail surface affected.A comparison of visitation patterns with trail condition indicates that redistribution of use would help to mitigate some erosion problems. Because trail condition is correlated to physical environmental factors, however, some sites will require intensive maintenance, even if visitation is low.The data from this survey have already been used in environmental analysis of proposed developments within the park and can be applied to long-range planning for the park trail system as a whole. 相似文献
64.
A simulation model was developed for assessing the effects of power plant impacts on fish populations. The model was based on biomass changes in a fish population that divided into 4 life stages: eggs, larvae, juveniles, and adults. Metabolism of fish was included in the model as assimilation and respiration with the effects of temperature push-pull regulation. A cohort technique was used for life stage transfers in the young stages. Compensation was included in terms of density-dependent mortality of the young fish. Power plant impacts on a fish population included entrainment (eggs and larvae) and impingement (juveniles and adults).The model was applied to the gizzard shad (Dorosoma cepedianum) population in Pool 14 of the Mississippi River in Illinois and lowa. The nearby nuclear power plant, the Quad-Cities Station, is located on the Illinois side. The simulation of the model with the 1976 field data estimates of the power plant entrainment and impingement predicted a 10 percent potential reduction of the population over 30 years. The simulated reduction of the population with the effects of different river flows showed that the result with the 1976 river flow data gave 1.5 times higher reduction than the results with data of other plant operation years, 1972 through 1975. Because the 1976 data recorded low river flow, the 10 percent reduction quoted above may be high. 相似文献
65.
Peter G. Ashton James B. Pickens Coryell Ohlander Bruce Benninghoff 《Journal of the American Water Resources Association》1980,16(4):738-744
ABSTRACT: Decisionmaking associated with the Nation's 1.7 billion acres of forest and range land has become increasingly complicated because of the rise in competition for resource use and in the awareness of environmental and social effects. This system analysis approach uses four models to synthesize pertinent masses of information into measures of economic, environmental, and social impacts. The system results can be used to help evaluate alternative national programs. The models are:
66.
Herbert W. Greydanus 《Journal of the American Water Resources Association》1978,14(2):477-480
ABSTRACT: Most of California's precipitation falls at the wrong place in the wrong season in relation to the water needs. Redistribution and regulation are essential. Aquifer systems – groundwater basins – can provide a share of the future cyclic storage regulation. There are some differences in management concepts in using a full basin in comparison with a partially dewatered basin. Legal, water quality, and physical impacts on aquifer systems, including subsidence, are concerns. Storage may be for the benefit of overlying water users or for distant areas. Extraction during dry periods or recharge methods will require careful planning. Existing rights and uses and equitable treatment of all parties must be assured. Financial compensation may be involved. Changes in methods of operation or degree of self-determination by affected water agencies will require committed watermanship to resolve. Legislation or amendments to organic acts may be needed but much can be accomplished within existing statutes. Environmental impacts which can be avoided by not using large surface storage sites are important. Energy for pumping will be a key consideration. About 40 percent of California is underlain by aquifer systems. This resource offers major potential in overcoming the maldistribution of natural water resources. 相似文献
67.
F. Douglas Shields 《Journal of the American Water Resources Association》1982,18(5):779-784
ABSTRACT: The environmental effects of flood control channel modifications such as clearing and snagging, straightening, enlargement, and/or paving can be quite severe in some cases. Information review reveals that several environmental features have been incorporated into the design, construction, operation, or maintenance of recent flood control channel projects to avoid adverse environmental impacts and enhance environmental quality. Typically, these features have been proposed by conservation agencies and designed with minimal quantitative analysis. Environmental features for channel projects include selective clearing and snagging techniques, channel designs with nonuniform geometry such as single bank modification and floodways, restoration and enhancement of aquatic habitat, improved techniques for placement of excavated material, and revegetation. 相似文献
68.
Raghu N. Singh Kenneth P. Wilkinson 《Journal of the American Water Resources Association》1974,10(3):415-425
ABSTRACT: The major objectives are (1) to identify the problems involved in measuring the environmental impacts of public projects from selected perspectives, and (2) to elaborate a sociological approach used in an empirical investigation in that respect. The construct of environmental impact of a planned action is generally operationalized from different perspectives and with different methodological emphases in the various disciplines. Even the term environment does not elicit agreement among users as to its exact meaning. Although there has been a steady increase in the number of studies from a sociological perspective concerning environmental problems, there is lack of sociological counsel in writing environmental impact statements. Overall, we lack sociological methodology and operational procedures for that purpose. In an attempt to bring some empirical focus to this field, attitudinal measures employed to discover how residents of a river basin perceived negative and positive environmental impacts of a proposed watershed development project are reviewed. These come from a study of creation of the Cooper Reservoir and Dam in Texas. Data on 343 heads of households m the selected areas were collected through structured questionnaires with items on personal information, a vested interest scale, a knowledge of the project scale, and an environmental impact scale. Data show that perception of impacts by residents is influenced significantly by degree of their vested interests involved. Variables for inclusion in a sociological model of environmental impact are suggested. 相似文献
69.
水电开发对河流生态系统的影响不容忽视,科学评估其影响有助于建立更可持续的水电开发模式。以武江干流为例,利用当量因子法和功能价值评估法,分析了武江干流梯级水电开发对受淹没影响的河岸带陆地生态系统和河流生态系统服务的效益及损失,并就其对河流生态系统服务的综合效应进行了评估。结果显示:武江干流水电开发使受淹没影响的河岸带生态系统和河流生态系统本身的服务价值均出现增加,价值增量主要体现在水文调节、水资源供给等服务方面;武江干流水电开发对河流生态系统服务的正效应大于负效应,正效应主要体现在发电、水文调节、气体调节等方面,负效应主要体现在维持生物多样性、土壤保持等支持服务方面。研究认为不同规模水电站的正负效应侧重点不同,不同流域单位电能的生态损失难以直接横向比较。结合多年来武江鱼类资源跟踪调查数据,分析了鱼类生物损失指数的变化趋势,探讨了水电开发在时间上的累积生态效应及水电服务的空间格局差异。由于生物多样性等服务的影响难以用货币直接衡量,加上水域的单位面积服务价值远高于其他生态用地类型,导致负效应的价值评估偏保守,武江干流水电开发的正负效应之比偏大。 相似文献
70.
OMAR DOMÍNGUEZ-DOMÍNGUEZ‡ LUIS BOTO† FERNANDO ALDA† GERARDO PÉREZ-PONCE DE LEÓN§ IGNACIO DOADRIO† 《Conservation biology》2007,21(1):168-180
Abstract: The Mesa Central of Mexico is of special conservation interest due to its high richness of freshwater fish species, of which the goodeines are one of the most representative groups. Through an integrated approach, we determined conservation priorities for goodeine populations. We based our recommendations on the genetic diversity (variation in five microsatellite DNA loci) in 10 populations of Zoogoneticus quitzeoensis and on an analysis of ecological (e.g., presence of exotic species), social (e.g., political situation), and environmental (e.g., pollution) information for 52 historical occurrence points for species in the genus Zoogoneticus . Patterns of genetic erosion and genetic diversity indices were closely associated with human impact. Recent bottleneck events were most evident in the populations from remnants of the lakes drained at the beginning of the twentieth century. We identified seven operational conservation units (OCUs), all of which should be conserved because they contain unique portions of the total variation of the species. Special attention needs to be given to increase genetic variability, recover population sizes, and reestablish contact among populations within OCUs. It is imperative to create an integrative and effective approach for the recovery and conservation of the freshwater fish diversity of Central Mexico that is based on social and natural sciences. 相似文献