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791.
引黄调水对汾河受水区水环境的影响 总被引:1,自引:0,他引:1
引黄入晋工程缓解了太原市水短缺问题。然而,近年来上游黄河水出现较严重污染。引黄调水对汾河受水区的影响尚不明确。论文基于连续观测和采样,分析了受水区河水、地下水水文过程、理化性质、主要离子、典型污染物邻苯二甲酸二丁酯以及大肠杆菌的含量和变化。结果表明:受水河流和河岸带地下水受引黄影响十分明显,含盐量和有机物含量显著增加,水环境整体退化;引黄导致汾河雨季高水位而旱季低水位的水文过程反转,且整个水文年内河水以饱和输水的方式补给浅层含水层,水位埋深变浅;汛期河谷发生洪水的风险大大增加;引黄导致汾河水电导率增大两倍左右,且河水由Ca-HCO3型变为Na-Cl·SO4型,而溶解有机碳含量增高约26%,UV254含量增大约24%;引水暂停期汾河水水化学特征趋于恢复,而河岸带地下水水化学特征未能恢复。长期来看,若引黄调水持续向河谷地下水输入大量Na+和Cl-等,且地下水埋深持续保持在较浅的范围,可能造成土壤盐碱化、植被退化和生态环境恶化等更加严重的后果。 相似文献
792.
西北干旱荒漠生态区脆弱性动态监测及驱动因子定量分析 总被引:4,自引:0,他引:4
全球气候变化和人类活动双重胁迫下,西北干旱荒漠生态区的脆弱生态系统发生了深刻变化。论文在充分考虑研究区生态环境背景特征(沙漠化、盐渍化、风力侵蚀、干旱等灾害严重)的基础上,引入极端气候灾害因子(指示气候变化)和大尺度景观格局指数(指示人类活动对生态景观的干扰),构建了西北干旱荒漠生态区的生态脆弱性评价体系,并对研究区2000—2013年的生态脆弱性时空变化格局及其驱动机制进行了定量分析和讨论。研究结果表明:西北干旱荒漠生态区的生态脆弱性总体上处于中-重度脆弱状态;其生态脆弱性空间分布格局总体上呈现自东向西递减的趋势,西部局部地区则呈现“E”字型格局,该分布格局主要受西北内陆地区大气环流以及三山夹两盆的特殊地貌影响;2000—2013年,西北干旱荒漠生态区生态脆弱性呈现减小趋势,其生态脆弱性变化状况受气温、降水以及人类活动影响显著。研究成果可以为西北干旱荒漠生态区的生态保护和治理提供决策支持。 相似文献
793.
Habituation of Adult Magellanic Penguins to Human Visitation as Expressed through Behavior and Corticosterone Secretion 总被引:8,自引:0,他引:8
Abstract: Ecotourism is increasing worldwide; hence, it is important to know how wildlife are affected behaviorally and physiologically by human visitation. We studied the effects of human visitation on the Magellanic Penguins ( Spheniscus magellanicus ) at Punta Tombo, Argentina, by monitoring changes in defensive head turns and plasma corticosterone (a hormone secreted in response to stress) for penguins with and without a history of tourist visitation. Habituation to human visitation was rapid. In penguins with no previous exposure to tourists, the number of defensive head turns and level of plasma corticosterone decreased significantly within 5 days of one 15-minute visit/day. Penguins living in tourist-visited and undisturbed areas secreted more corticosterone when captured and restrained than penguins visited by a person. Penguins in tourist areas, however, did not show as strong a corticosterone response to capture and restraint as did penguins in areas without tourists. This difference was due to a decreased capability of the adrenocortical tissue to secrete corticosterone in tourist-visited birds. Although our data show no direct negative effects of tourism on Magellanic Penguins at Punta Tombo, consequences of a modification of physiological capabilities (e.g., adrenocortical function) may not become apparent until much later in life. The physiological differences between tourist-visited and undisturbed groups of Magellanic Penguins emphasize the importance of monitoring the effects of anthropogenic disturbances on wildlife at multiple levels. 相似文献
794.
基于灰色-马尔可夫藕合模型的区域建设用地需求预测 总被引:1,自引:0,他引:1
建设用地需求的中长期准确预测是当前土地资源规划和利用的重点和难点。本文将灰色和马尔可夫两种预测模型相结合,建立灰色-马尔可夫藕合模型,以广东省揭阳市为例,对1997到2010年间主要建设用地规模进行了需求预测,同时与其它几种常规的预测方法进行了比较。结果表明,人文驱动力相关预测法误差相对较大,其中国内生产总值(GDP)相关法准确度要优于人口相关法。趋势线法计算简单,预测准确度也相对较高,但只适于短期预测。灰色预测法精确度较高,计算需要模型的支持、专业性强。灰色-马尔可夫预测法由于是对灰色预测的偏离值进行了纠正,因而准确度最高。尽管该方法需要大量数据的支持,计算量大,但仍是值得推荐的高准确度的区域建设用地的专业预测方法。 相似文献
795.
前哨动物能够在污染物对生态系统或人体健康产生明显影响之前做出反应,所以利用前哨动物能够对环境污染的健康风险做早期预报,同时可提供环境中污染物种类、污染水平、生物可利用性、富集代谢等多方面的信息.虽然来自前哨动物的信息不能直接外推于人,但由于动物和人体结构和功能的相似性,这些信息可作为污染物对人体作用的早期警报.论文对作为前哨动物的某些鱼类、两栖动物和哺乳动物在环境污染物人体健康风险评价中的应用进行了简要概述,讨论了它们作为前哨动物各自的优缺点和适用范围,最后建议在国内大力开展前哨动物生态毒理学调查,以促进人体健康风险评价工作. 相似文献
796.
Prehistoric Decline in Freshwater Mussels Coincident with the Advent of Maize Agriculture 总被引:1,自引:0,他引:1
Abstract: During late prehistory, high population densities and intensive agricultural practices of Native American societies had profound effects on the pre-Columbian landscape. The degree to which Native American land use affected aquatic ecosystems is unknown. Freshwater mussels are particularly sensitive harbingers of modern-day ecosystem deterioration. We used data from prehistoric Native American shell middens to examine prehistoric trends in abundance of freshwater mussels of the genus Epioblasma in North America during the last 5000 years. The relative abundance of Epioblasma declined steadily during this period, a result that could be explained either by an increase in human impacts to streams or by long-term climatic changes unrelated to human activities. The rate of decline of Epioblasma increased significantly, however, after the advent of large-scale maize agriculture in the southeastern United States about 1000 years before the present. Our results suggest that human land-use activities in prehistory caused changes in freshwater mussel communities that were lower in magnitude but similar in direction to changes caused by recent activities. 相似文献
797.
798.
人类活动对北京东灵山地区景观格局影响分析 总被引:38,自引:1,他引:38
干扰改变景观格局,同时又受景观格局的影响,干扰是景观异质性的一个主要来源。应用ILWIS地理信息系统,以1∶20000植被图为基础,结合野外考察,分析了北京东灵山地区森林景观空间格局,采用缓冲区分析方法,研究了人类活动对该地区森林景观格局的影响。研究结果表明,在东灵山地区,人类活动的强弱与景观的破碎化表现出一定的相关性。人类作用强的地区斑块面积较小,作用弱的地区斑块面积较大,人类的活动对该地区的景观破碎化产生了明显的影响。随着距所选择的干扰区的远近,几个景观多样性指数没有表现出有规律的大小变化。虽然该地区人类活动有愈来愈强的趋势,但目前决定该地区景观空间格局的因子主要还是自然要素,人类活动虽然也对该区的景观格局产生了一定的影响,但还不是决定因素 相似文献
799.
Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study 总被引:1,自引:0,他引:1
Robert M. Hamwey 《Mitigation and Adaptation Strategies for Global Change》2007,12(4):419-439
To date, international efforts to mitigate climate change have focussed on reducing emissions of greenhouse gases in the energy,
transportation and agriculture sectors, and on sequestering atmospheric carbon dioxide in forests. Here, the potential to
complement these efforts by actions to enhance the reflectance of solar insolation by the human settlement and grassland components
of the Earth's terrestrial surface is explored. Preliminary estimates derived using a static two dimensional radiative transfer
model indicate that such efforts could amplify the overall planetary albedo enough to offset the current global annual average
level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30% or 0.76 Wm− 2. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use
of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. While
a scoping analysis indicates the technical feasibility of sufficiently enhancing human settlement and grassland albedos to
levels needed to achieve reductions in radiative forcing projected here, additional study is required on two fronts. Firstly,
the modelled radiative forcing reductions are static estimates. As they would generate climate feedbacks, more detailed dynamic
climate modelling would be needed to confirm the stationary value of the radiative forcing reduction that would result from
land surface albedo amplification. Secondly, land surface albedo amplification schemes may have important economic and environmental
impacts. Accurate ex ante impact assessments would be required to validate global implementation of related measures as a viable mitigation strategy. 相似文献
800.
Sustainability can only be assured with a human-ecological understanding of the complexinteractions among environmental,economic and social/cultural factors and with careful planningand management grounded in ecological principles. This paper will probe an integrative methodologyfor achieving environmentally sound, economically productive, and ecologically responsibledevelopment in urban and industrial areas of China through ecological regulation. The central objec-tive is to promote highly efficient resource use rather than high speed development,harmonious sys-tem′s relationship rather than inflexible compartmentalization, and robust and vital self-organizationrather than bureaucrstic control. This ecological order is to be regulated through technological inno-vation,institutional reform, and behavioral incentives that promote positive economic dcvelopmentwhile mitigating negative environmental impacts. 相似文献