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排序方式: 共有821条查询结果,搜索用时 31 毫秒
61.
温彦平 《环境监测管理与技术》2015,27(1):22-26
选取太原汾河景区跨桥断面8个监测点,在2012年3月—2013年10月期间对河流8项水质参数进行监测,并结合派生的水体综合污染指数及主成分分析方法分析和评价景区水污染时空变化特征。结果表明,景区水质污染变化时空差异明显,上游污染相对较小,下游污染较重;春季溶解氧和p H值变化幅度最大,夏季除总氮和氨氮外,其他各污染物均有显著变化特征,秋季则以氨氮、总氮和总磷变化最为显著。主成分分析结果显示,虽然各监测点水体污染的关键影响因子不同,但总磷是太原市河流水体污染的共同解释因子。 相似文献
62.
Using Multi-Scale Sampling and Spatial Cross-Correlation to Investigate Patterns of Plant Species Richness 总被引:8,自引:0,他引:8
Land managers need better techniques to assess exoticplant invasions. We used the cross-correlationstatistic, I
YZ, to test for the presence ofspatial cross-correlation between pair-wisecombinations of soil characteristics, topographicvariables, plant species richness, and cover ofvascular plants in a 754 ha study site in RockyMountain National Park, Colorado, U.S.A. Using 25 largeplots (1000 m2) in five vegetation types, 8 of 12variables showed significant spatial cross-correlationwith at least one other variable, while 6 of 12variables showed significant spatial auto-correlation. Elevation and slope showed significant spatialcross-correlation with all variables except percentcover of native and exotic species. Percent cover ofnative species had significant spatialcross-correlations with soil variables, but not withexotic species. This was probably because of thepatchy distributions of vegetation types in the studyarea. At a finer resolution, using data from ten1 m2 subplots within each of the 1000 m2 plots, allvariables showed significant spatial auto- andcross-correlation. Large-plot sampling was moreaffected by topographic factors than speciesdistribution patterns, while with finer resolutionsampling, the opposite was true. However, thestatistically and biologically significant spatialcorrelation of native and exotic species could only bedetected with finer resolution sampling. We foundexotic plant species invading areas with high nativeplant richness and cover, and in fertile soils high innitrogen, silt, and clay. Spatial auto- andcross-correlation statistics, along with theintegration of remotely sensed data and geographicinformation systems, are powerful new tools forevaluating the patterns and distribution of native andexotic plant species in relation to landscape structure. 相似文献
63.
Jan Narveson 《Journal of Agricultural and Environmental Ethics》1995,8(2):145-156
Environmental Ethics is the ethics of how we humans are to relate to each other about the environment we live in. The best way to adjust inevitable differences among us in this respect is by private property. Each person takes the best care of what he owns, and ownership entails the free market, which enables people to make mutually advantageous trades with those who might use it even better. Public regulation, by contrast, becomes management in the interests of the regulators, or of special interests, such as lovers of rare species-not the people they're supposed to be serving. 相似文献
64.
Lorenz King 《中国减灾(英文版)》2002,(3)
20 0 0wasarelativelynormalyearintermsofglobaldisasterevents.Thegloballossfromnaturaldisasterswasapproximately 30billionUSD ,whereasthatinanyofthepreviousyearshadexceeded 1 0 0billionUSD .Theinsurancelossin 2 0 0 0wasonly 8.3billionUSD ,with 92 0 0 personskilled .Therewasn… 相似文献
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68.
F. Andrew. Schoolmaster 《Journal of the American Water Resources Association》1992,28(3):495-505
ABSTRACT: Texans participate directly in water policy decision-making through a referendum process involving amendment of the state's constitution. Prior to 1985, Texans voted on eight amendments. Five of these were ratified (1957, 1962, 1966, 1971, 1976), and collectively resulted in the creation of the Water Development Fund, with an authorization level of $600 million, and the Texas Water Development Board, the organization charged with administering the fund. Three other amendments were defeated in 1969, 1976, and 1981 by ever-increasing margins. From 1985 to 1991, six additional amendments were proposed and subsequently ratified, resulting in a $1.8 billion increase in Water Development Fund authorization and the creation of an agricultural water conservation fund and bond insurance program. County-level electoral data for the 1985–1991 referenda were mapped to assess sectional and regional factors underlying public opinion regarding these water resource development and funding programs. Regional contrasts were most pronounced for the 1989 and 1991 referenda that targeted economically distressed areas across the state, particularly the colonias located along the Rio Grande, and the 1989 amendment that removed a time limit on the issuance of agricultural water conservation bonds. As a specific case study, the Texas experience could serve as a guide in California where similar constitutional restrictions require tax and spending programs to be approved by voters, and in other states that may be considering the development of similar state-level financial programs for water projects. 相似文献
69.
Simon Niemeyer 《Journal of Environmental Policy & Planning》2020,22(1):16-29
ABSTRACTEcological democracy confronts a challenge of not only reconciling democracy and ecology, but doing so where human activities and their environmental consequences are increasingly global. Deliberative scholars dealing with these issues emphasise reflexive governance, involving the contestation of discourses, as part of the solution, mostly aimed at high-level institutions and intergovernmental cooperation. However, even at this level democracy demands responsiveness to the citizen. To this end, the paper explores citizen-level deliberation to inform possibilities for ecological democracy writ large, via a growing literature on deliberative governance and polycentrism. Different system levels are connected via ecologically reflexive capacity and the discursive conditions under which it is enhanced, including in small-scale minipublics. This understanding informs mechanisms for ‘scaling up’ deliberative quality to the wider public sphere via regulating the manipulation of public discourse. Minipublic deliberation, properly harnessed, can serve to decontaminate public debate of anti-reflexive strategic arguments and reshape public discourse. Such anti-reflexive strategies seek to shape the public will, specifically by de-emphasising ecology via intuitive arguments that short-cut public reasoning. Acting as discursive regulatory trustees, minipublics can improve reflexivity in the wider system via a nested polycentric approach that discursively connects citizens’ deliberation to the global system both horizontally and vertically. 相似文献
70.
基于3S技术的震害快速评估 总被引:1,自引:0,他引:1
地震是人类面临的重大自然灾害之一,破坏性地震发生后,对震害的快速评估有利于政府及有关部门对灾情迅速做出应急反应,实施救援。地理信息系统(GIS)、遥感(RS)和全球定位系统(GPS)合称为3S技术。随着计算机技术和地球空间科学的发展。3S技术已逐渐应用于防灾减灾领域。探讨了应用3S技术替代传统的经验性估计决速评估震害的技术路线、方法和前景。首先,归纳了目前防震减灾信息及辅助决策系统建设取得的成绩和存在的问题。通过两个破坏性地震的震害实例,说明了应用基于GIS的系统快速评估震害的可能性和有待重点解决的问题。然后。通过新疆一次地震的遥感图像的变化检测,展示了震害快速评估中借助遥感数字图像处理技术的前景。在上述综合分析的基础上,讨论了三者结合的重要性、潜在功能和优点。 相似文献