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261.
旅游推力—引力因素是研究旅游行为潜在动机的有效方法。本项研究在大量实地调查的基础上,应用因子分析法(Factor Analysis),以山岳型旅游地黄山为案例区,从推力因素和引力因素两个领域定量分析黄山旅游者旅游动机的潜在特征,确立5个推力公因子和4个引力公因子,同时运用对比分析法。分析了中国黄山与韩国国家公园推力-引力因素的共性和个性。  相似文献   
262.
低强度火烧对长白山林区蒙古栎林的影响   总被引:3,自引:0,他引:3  
为了减少林区内可燃物的载量,降低森林的燃烧性,对蒙古栎林进行了试验火烧和火烧迹地调查,主要研究低强度火烧对蒙古栎林森林生态系统的影响。地表可燃物载量调查采用线状相交可燃物取样调查方法,按不同径级调查可燃物载量。由于火烧引起部分枯死木倒伏和下木层树枝被烧断,火烧后所有试验地上的径级可燃物载量都有所增加。但地表易燃可燃物减少,林分火险降低。试验火烧为低强度地表火,试验结果表明低强度火烧对上层林木的生长没有明显影响,但下层林木的死亡率可达25%~42%。火烧降低了下层林木的密度,改善了林分卫生状况。试验结果表明,在长白山林区蒙古栎林内,可以采用低强度火烧来降低火险。  相似文献   
263.
Managing Recreational Trail Environments for Mountain Bike User Preferences   总被引:1,自引:0,他引:1  
N  = 406), highlight some important issues concerning the design and management of wildland recreation environments that are primarily used for mountain biking. For example, bikers were found to significantly prefer water bars above all other tested soil erosion management techniques; trail erosion factors, including the presence of rocks, roots, and gullies, all added to biking experiences on average; trail design factors, such as the presence of turns, bumps, jumps, and obstacles, all added to biking experiences in general. These findings were used to address questions that resource managers should consider when striving to effectively manage wildland recreation areas primarily used for mountain biking.  相似文献   
264.
本文概述了吉林省东部长白山区农业气候资源的立体变化规律,分析了如何根据立体气候规律安排农作物品种的垂直布局,确定主要特产植物适宜裁培高度、森林植被类型和立体农业生态经济系统建设等问题,指出了充分利用气候资源搞好山区农业立体开发的有效途径。  相似文献   
265.
Recent studies have questioned the ability of the Department of Energy to successfully construct and operate a high-level nuclear waste repository at Yucca Mountain, Nevada, USA, consistent with current Environmental Protection Agency standards and Nuclear Regulatory Commission regulations. Questions focus on whether demonstration of compliance with the agency's standards is based too much on numerical calculations and analyses that the Department of Energy must conduct to project the long-term performance of the repository. Unless these questions are resolved, the licensing of the repository could be withheld or delayed by litigation. This article reviews the extent to which laws that govern the siting of high-level nuclear waste repositories require scientific certainty in any findings about the environmental consequences of locating a repository.  相似文献   
266.
Siting a geologic repository for isolating highlevel nuclear waste up to 10,000 years is a controversial undertaking never before attempted in the United States. The Nuclear Waste Policy Act of 1982 exempted repository siting from important requirements for environmental review under the National Environmental Policy Act. In December 1987, the Nuclear Waste Policy Amendments Act identified Yucca Mountain as the first site to be characterized for a high-level nuclear waste repository. In light of the unproven nature of the technology being evaluated, the scientific uncertainties associated with Yucca Mountain, and the lack of proven methods for risk evaluation, the environmental policies for repository siting represent a significant departure from more traditional, comprehensive, and interdisciplinary environmental review for siting nuclear projects. The policies warrant further study by those interested in how present as well as future decisions about complex technologies may be made.  相似文献   
267.
基于GIS的祁连山生态敏感性评价   总被引:1,自引:0,他引:1  
以遥感数据为基础数据源研究祁连山的生态环境特点和主要生态问题,并结合客观条件及评价因子的选取需具有代表性、可计量性的原则,选取气候舒适度指数、土地沙化指数、土地盐碱化指数、水土流失指数和生物多样性指数共5项评价因子对祁连山生态敏感性进行综合评价。运用GIS技术在单因子评价的基础上,再利用空间叠加分析功能和重分类工具进行多因子综合评价,划分5类生态敏感等级,由大到小依次为高敏感性、较高敏感性、中等敏感性、较低敏感性和低敏感性。结果表明,祁连山生态敏感性空间分异明显,高敏感性地区主要分布在祁连山西部地区,低敏感性地区主要分布在东部地区。生态敏感性总体都处于中等偏低的水平上,其中,中等以下的地区占研究区总面积的69.7 8%,高敏感性、较高敏感性占研究区的30.2 2%,表明对于祁连山的生态保护还是卓有成效的,但一些地区还存在不少问题,导致生态敏感性偏高。因此,未来对于祁连山生态环境保护任务依然艰巨,对于高敏感性区域的西部地区应该进行严格保护和生态治理,对于低敏感性区域的东部地区要持续加强生态保护,减少人为活动影响。  相似文献   
268.
The fitness consequences of dispersal decisions are difficult to quantify, especially for long-lived species with complex social systems. To calculate those consequences for male mountain gorillas, from the perspective of both subordinate and dominant males, we used behavioral and demographic data obtained over 30 years from the Virunga Volcano population to develop an agent-based model that simulates the life history events, social structure, and population dynamics of the species. The model included variables for birth rates, mortality rates, dispersal patterns, and reproductive skew. The model predicted an average lifetime reproductive success (LRS) of 3.2 for philopatric males (followers) and 1.6 for emigrants. The benefits of philopatry were most sensitive to opportunities for social queuing and to female transfer preferences, but philopatry remained the best strategy over a wide range of group conditions and hypothetical simulations. The average LRS for dominant males was 4.5 when a subordinate stayed and 4.6 when the subordinate emigrated. The dispersal decision of the subordinate male had little impact on the fitness of the dominant male because it came relatively late in the dominant males reproductive life span, and it changed his group composition only incrementally. The fitness consequences for the dominant male were most sensitive to the degree of reproductive skew. Since subordinates suffer a fitness loss when they leave a group, they should accept whatever reproductive restraint is needed to avoid eviction, and the dominant male does not need to offer concessions for them to stay. The dominant male may offer reproductive concessions for other reasons, such as peace incentives or to confuse paternity, or he may not have complete control of reproduction within his group.Communicated by D. Watts  相似文献   
269.
Over the past few decades, socioecological models have been developed to explain the relationships between the ecological conditions, social systems, and reproductive success of primates. Feeding competition, predation pressures, and risk of infanticide are predicted to influence how female reproductive success (FRS) depends upon their dominance rank, group size, and mate choices. This paper examines how those factors affected the reproductive success of female mountain gorillas (Gorilla beringei beringei) of the Virunga Volcanoes, Rwanda from 1967–2004. Reproductive success was measured through analyses of interbirth intervals, infant survival, and surviving infant birth rates using data from 214 infants born to 67 females. Mountain gorillas were predicted to have “within-group scramble” feeding competition, but we found no evidence of lower FRS in larger groups, even as those groups became two to five times larger than the population average. The gorillas are considered to have negligible “within-group contest” competition, yet higher ranked mothers had shorter interbirth intervals. Infant survival was higher in multimale groups, which was expected because infanticide occurs when the male dies in a one-male group. The combination of those results led to higher surviving birth rates for higher ranking females in multimale groups. Overall, however, the socioecological factors accounted for a relatively small portion of the variance in FRS, as expected for a species that feeds on abundant, evenly distributed foliage.  相似文献   
270.
广州白云山风景区阔叶植物叶片中的多环芳烃   总被引:1,自引:0,他引:1  
王晓丽  彭平安  周国逸 《生态环境》2007,16(6):1597-1601
多环芳烃(PAHs)在环境中分布极广,作为持久性亲脂有机污染物,具有很强的生物累积性。植物对周围环境有着高度的依赖性,阔叶植物由于叶面巨大的表面积,容易吸收富集环境中的多环芳烃。采集了白云山9种阔叶植物叶片样品,利用GC-MS对样品中的多环芳烃进行了定量分析。结果表明,白云山阔叶植物叶片样品中的PAHs以芘所占比例最高,总PAHs为460.2~1303.5ng·g-1(干质量)。从组成上看,白云山阔叶植物叶片中多环芳烃以3环、4环为主,比较发现这种组成特征与大气中PAHs相似。运用分子标志物比值法分析PAHs的来源,发现阔叶植物样品中PAHs主要是热成因来源。广州市工业发达,环境中含有较高PAHs在白云山阔叶植物叶片中已有明显的反映,应加强对环境中PAHs监控和治理。  相似文献   
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