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1.
近25年来青海湖流域景观结构动态变化及其对生态系统服务功能的影响 总被引：13，自引：0，他引：13
青海湖是我国最大的内陆高原咸水湖,是维系青藏高原东北部生态安全的重要水体。本文基于青海湖流域1977年MSS影像、1987年TM影像和2000年ETM影像,在地理信息系统(GIS)和遥感技术的支持下,采用景观格局分析方法,应用Costanza生态系统服务价值算法,揭示了青海湖流域景观生态服务价值的动态变化。结果表明,青海湖流域生态系统服务价值总体呈下降趋势,由1977年的423×108元降低到2000年的364×108元,年均损失2.57×108元;从生态系统服务功能价值来讲,废物处理和水源涵养价值贡献率超过了58%,单项服务功能价值均呈下降趋势,其中气候调节功能缺失最明显减少达32%;就生态系统服务价值构型而言,草地、湿地和水域的价值贡献率超过了97%,成为构成青海湖生态系统服务价值的主体,湿地面积的大幅度减少可能是青海湖流域生态系统服务功能变化的主要原因。 相似文献
2.
人类活动对生态系统服务价值的影响——以纸坊沟流域为例 总被引：8，自引：1，他引：7
人类活动及政策对生态系统服务价值变化具有重要影响,但目前从长时间尺度上还缺乏对其影响过程的系统研究。本文以受人类活动强烈干扰的黄土高原典型丘陵沟壑区安塞县纸坊沟为例,以1938年～2000年的土地利用变化和其它文献资料为基础,计算了该流域不同时期的生态服务价值,分析了导致流域生态服务价值变化的人类活动及政策原因。研究表明,在受人类干扰极少的1938年,流域生态系统服务总价值最高,达到5.74×108元;1938年～1978年,由于特定的历史原因、不合理的政策导向、淡薄的生态保护意识以及人口增长使得流域内生态环境恶化,生态系统服务总价值在1958年降至最低点,仅有1.92×108元,1973年～1978年的流域治理效果甚微;1978年～2000年,随着生态保护意识的增强,流域综合治理的深入,以及退耕还林等各项政策的正确实施,流域内生态环境得到明显改善,2000年流域生态服务价值达到3.43×108元,但与1938年相比仍有2.31×108元的差距,表明流域生态系统服务价值仍有较大的提升空间,退耕还林还需进一步因地制宜加强优化,生态保护和综合治理仍要长期坚持。 相似文献
3.
山地丘陵地区农地资源价值评估——以湖北省宜昌市为例 总被引：11，自引：3，他引：11
本文在回顾农地价值理论及评估方法的基础上，以湖北省宜昌市农地为代表，采用收益还原法和条件价值法，通过实地抽样调查对不同地类的农地的市场价值和非市场价值进行评估。在尽量减少评估偏差的前提下，得到宜昌市农地主要地类资源总价值：宜昌市耕地总价值约为396.32×108元，园地总价值约为509.24×108元，林地总价值约为29.37×108元，水域总价值约为30.30×108元。其中，单位耕地的市场价值约为9.44×104元/hm2，非市场价值约为2.49×104元/hm2；园地的市场价值约为54.88×104元/hm2，非市场价值约为3.97×104元/hm2；林地的非市场价值约为0.23×104元/hm2；水域的非市场价值约为6.32×104元/hm2。根据价值评估过程，得到相关结论：农地总价值应该包含市场价值和非市场价值；农地非市场价值与支付者对农地生态功能的认识有显著关系；不同地类的资源价值对农业种植结构调整具有较强的参考意义；对农地非市场价值的认识加深有助于优化农地资源配置。 相似文献
4.
广东省1987年至2004年森林生态系统服务功能价值动态评估 总被引：2，自引：0，他引：2
广东省自改革开放特别是1987年以来,高速的经济发展、快速的城市化过程,对广东的森林生态系统、景观格局变化和服务功能退化带来较大的影响。为了实现广东省森林生态系统的经济效益和生态效益的协调统一以及为森林生态效益价值的合理补偿和森林资源的科学经营、永续利用提供一些依据,本文根据广东省1987年、1996年和2004年的森林资源基础数据,利用物质量和价值量相结合的方法,并参考了Costanza等提出的生态系统功能效益单位价值,分别计算出各个阶段广东省森林生态系统服务功能价值为：1987年199.88×108元,1996年226.25×108元,2004年236.8 1×108元,其中生态功能和经济功能价值在总功能价值中所占比重的比例分别为：1987年5.1∶1, 1996年6.1∶1,2004年6.2∶1,这表明在这段时期广东省森林生态服务功能价值持续增加,且生态功能价值的比重在缓慢提高,这与我国黑龙江、湖南、黔东南等接近,但与云南、日本、美国等还有较大差距。 相似文献
5.
北京市湿地生态系统服务功能价值评估 总被引：1，自引：0，他引：1
在遥感调查和实地调查的基础上,综合运用资源经济学、生态经济学方法,针对北京大都市的特点建立北京湿地分类体系、生态系统服务功能价值指标体系和评价方法,对2009年北京市湿地生态系统服务功能价值进行了评估。结果表明：2009年北京市湿地生态系统服务功能价值为2137．31亿元,其中经济功能价值为33．99亿元,占总价值的1．59％;社会功能价值为1340．94亿元,占总价值的62．74％;生态功能价值为762．38亿元,占总价值的35．67％,反映了北京湿地生态系统在经济、社会、生态三方面多功能服务于首都经济社会发展和生态城市建设中的地位和作用,可为北京市湿地生态系统保护、恢复和重建决策提供科学依据。 相似文献
6.
区域土地整理综合效益测算——以徐州市贾汪区为例 总被引：7，自引：2，他引：7
土地整理效益评价是土地整理技术研究的一项基础工作。土地整理具有经济产出价值、生态服务价值及社会保障价值，针对这3种价值，本文分别提出3种测算方法即传统市场法、土地生态系统服务价值系数法、替代市场法。传统市场法即采用收益还原法；生态功能价值系数法是根据各地类生态服务价值系数，来测算土地整理实施的生态服务价值；而替代市场法则以土地作为农民社会保障的替代物，以用商业保险的方式计算一次性投保所需的资金作为土地整理社会保险的价值。本文以徐州市贾汪区为例，全面、科学地测算了区域土地整理带来的价值，研究表明：该区域自1999年以来，土地整理效益总价值达9.98×108元，其中经济产出价值达5.57×108元，社会保障价值达7.10×108元，达到了增加有效耕地，改善经营生产条件的目的；然而生态服务价值却损失2.69×108元，表明土地整理的生态风险防治还没有纳入土地整理的内容。本文所提出的方法可以很好地测算土地整理经济效益、社会效益、生态效益的经济价值，为综合评价土地整理效益并指导土地整理的实践活动提供依据。 相似文献
7.
辽宁近海海洋生态系统服务及其价值测评 总被引：6，自引：1，他引：5
参照千年生态系统评估的生态系统服务分类体系,以及生态系统服务类别间的相互作用,将辽宁近海海洋生态系统服务归纳为资源供给、环境调节和人文社会三大类共10项,并采用生态经济学的理论和研究方法,对辽宁近海海洋生态系统服务价值进行测评。结果表明:①2007年辽宁近海海洋生态系统服务总价值为710.35×108元,相当于2007年辽宁省GDP的6.44%。平均单位面积海域的生态服务价值为203.02×104元/km2;②在辽宁近海海洋生态系统服务总价值中,资源供给服务、环境调节服务、人文社会服务价值分别占33.18%、15.04%和51.78%。从所评价的10项海域生态服务的价值量大小看,依次为旅游娱乐价值食品供给价值水质净化调节价值空气质量调节价值干扰调节价值气体调节价值科研文化价值基因资源供给价值有害生物与疾病的生物调节与控制价值原材料供给价值。 相似文献
8.
森林生态系统服务流量过程研究 总被引：4，自引：0，他引：4
生态系统服务研究是生态学和生态经济学研究的热点和前沿，但迄今为止对生态系统服务流量过程的研究在世界范围内仍处于薄弱环节。本文以千烟洲中亚热带人工林生态系统为例，以2005年-2007年3年的定位监测数据为基础，研究了4类典型生态系统服务的流量过程。研究表明，千烟洲森林生态系统的年均生物量生产、气体调节、水源涵养和土壤保持服务价值的范围分别为（497.48±33.66） 元/（hm2·a）、（2189.21±247.18） 元/（hm2·a）、（1432.40±454.32）元/（hm2·a）和（224.55±8.82）元/(hm2·a)。4类典型生态系统服务流量均表现出显著的季节变化，生物量生产、气体调节和水源涵养服务表现为连续性实现，而土壤保持服务为离散型实现。年内某些日，森林生态系统产生负的气体调节和水源涵养流量。就各月平均流量而言，水源涵养和土壤保持服务的最大流量发生在6月份，分别为274.74 元/（hm2·month）和47.89元/（hm2·month），生物量生产的最大流量出现在8月，为65.19元/（hm2·month），最大的气体调节服务流量出现在7月，为303.67元/（hm2·month）。对于生物量生产、气体调节、水源涵养和土壤保持服务，夏季产生的相应服务价值分别占38.11%、37.15%，25.67%和42.53%。本研究有助于增进对生态系统服务形成机理与强度的认知，同时能为生态系统服务的保育提供依据。 相似文献
9.
内蒙古河套灌区农田生产和乌梁素海湿地保护综合模型分析 总被引：2，自引：0，他引：2
灌溉农业是世界上常见的生产活动之一,但失衡的农业生产会造成周边湿地退化和生态系统服务功能降低。本文通过建立农田生产和湿地保护综合模型,模拟内蒙古河套灌区农田-乌梁素海湿地生态系统价值的变化规律,以寻求实现农业和湿地生态系统价值最大化的措施。以2002年的数据作为基准,控制其他因素不变的情况下,模型分析得到当施肥量为 252.3 kg N/hm2时,系统的总价值量达到最大,为24.40×10.8元。此外,湿地子系统价值和河套灌区的引水量成正比,和农田灌溉配额成反比。将农田灌溉配额减少60％,系统总价值将增加70％。因此,在目前灌区可供水量有限的情况下,控制农田施肥量和降低灌溉配额是保持河套灌区农业生产和乌梁素海服务价值最优化的有效措施。 相似文献
10.
基于多源数据融合的南四湖湿地生态系统服务功能价值评估 总被引：1，自引：0，他引：1
随着对湿地生态系统研究的深入,湿地的生态服务价值越来越受到学者的重视。研究以南四湖湿地生态系统为例,通过遥感和地理信息系统软件处理高清影像解译生成的景观数据以及MODIS处理生成的NPP数据,运用市场价值法、碳税法与造林成本法、影子工程法、费用支出法、专家估算法、替代费用法以及生态价值等多种方法对南四湖湿地生态系统物质生产功能、大气调节功能、蓄水功能、调蓄洪水功能、休闲娱乐功能、文化科研功能、养分循环功能以及生物栖息地功能等服务功能价值进行估算。结果表明:①南四湖湿地服务功能价值总和为131亿元,其中调节功能价值最大,达到56.77亿元,其次是支持功能和文化功能,价值量为52.77亿元和15.07亿元,最后是物质生产功能价值为6.39亿元;②虽然人工湿地面积占研究区域总面积的59%以上,其生态服务功能价值总量还不到自然湿地的生态服务功能价值总量的一半。 相似文献
11.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
12.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
13.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
14.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
15.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
16.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
17.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
18.
Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
19.
Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
20.
Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献