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211.
中国改革开放的40年也是生态环境保护管理体制不断改革和飞跃的40年。自1972年开展生态环境保护工作起,围绕着解决不同发展阶段突出环境问题的需要,每10年左右实现一次环境管理体制改革"大跨跃",不断改革、创新和发展了具有中国特色的生态环境保护治理体系与模式。坚持在发展中解决环境问题,以改善生态环境质量为核心,逐步构建了符合不同发展阶段特征的生态环境保护管理体系,包括完备的生态环境规划政策体系、完善的生态环境治理体系、完整的生态环境保护法律体系。在新时代中国特色社会主义建设过程中,应瞄准建设美丽中国的战略目标,立足中国、放眼世界,坚持绿色发展,做好顶层设计,构建生态环境管理体系新格局,共建清洁美丽世界。  相似文献   
212.
松属(Pinus L.)约113种,是松科现代属中最原始的类群。松属植物种类丰富且研究领域广泛,对其已经积累的资料数据进行系统梳理总结十分必要。本文通过总结国内外松属大化石资料,结合分子系统发育、地质背景和地理隔离事件讨论了其地史分布及植物地理学意义;该属化石在早白垩世至全新世地层中均有记录。化石证据表明松属很可能在早白垩世(之前)起源于西欧地区,从这一起源地通过北大西洋陆桥扩散到北美洲东部,而东亚的类群可能是从北美洲西部经过白令陆桥散布的。在晚白垩世分化出双维管束松亚属Subgenus Pinus L.及单维管束松亚属Subgenus Strobus (D.Don) Lemmon,前者更接近祖先类群。古新世由于全球显著增温以及白垩纪末期大灭绝等地质事件的影响使松属数量急剧减少,在晚始新世至中新世时期随着气温转凉转冷再次分化扩散,中新世达到其发展高峰且分布面貌与现代类群近似。松属多样性时空历史可能和新生代气候变迁及晚新生代构造运动塑造的山地隆升等环境变化紧密相关。  相似文献   
213.
“历史模型”与灾害研究   总被引:3,自引:3,他引:3  
灾害研究涉及多学科的交叉领域.水灾“历史模型”的研究方法是循社会科学的历史科学与自然科学的水利学科相结合的研究途径.将“历史模型”引人灾害研究.增强了研究与自然环境和社会经济密切相关的灾害问题的能力.本文论述了“历史模型”方法及其在灾害问题研究中的应用.  相似文献   
214.
The thylacine (Thylacinus cynocephalus), one of Australia's most characteristic megafauna, was the largest marsupial carnivore until hunting, and potentially disease, drove it to extinction in 1936. Although thylacines were restricted to Tasmania for 2 millennia prior to their extinction, recent so‐called plausible sightings on the Cape York Peninsula in northern Queensland have emerged, leading some to speculate the species may have persisted undetected. We compiled a data set that included physical evidence, expert‐validated sightings, and unconfirmed sightings up to the present day and implemented a range of extinction models (focusing on a Bayesian approach that incorporates all 3 types of data by modeling valid and invalid sightings as independent processes) to evaluate the likelihood of the thylacine's persistence. Although the last captive individual died in September 1936, our results suggested that the most likely extinction date would be 1940. Our other extinction models estimated the thylacine's extinction date between 1936 and 1943, and the most optimistic scenario indicated that the species did not persist beyond 1956. The search for the thylacine, much like similar efforts to rediscover other recently extinct charismatic taxa, is likely to be fruitless, especially given that persistence on Tasmania would have been no guarantee the species could reappear in regions that had been unoccupied for millennia. The search for the thylacine may become a rallying point for conservation and wildlife biology and could indirectly help fund and support critical research in understudied areas such as Cape York. However, our results suggest that attempts to rediscover the thylacine will be unsuccessful and that the continued survival of the thylacine is entirely implausible based on most current mathematical theories of extinction.  相似文献   
215.
本文运用文献计量学方法,以《中国环境管理干部学院学报》2001~2005年发表的论文作为研究对象,分别就载文及作者的情况进行了统计分析,为该刊将来的发展提供参考数据。  相似文献   
216.
Non‐native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer‐reviewed literature to evaluate responses of arthropod communities and functional groups to non‐native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty‐two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web‐building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to ecological change, arthropods may be ideal targets for restoration and conservation activities. Efectos de las Plantas Invasoras sobre los Artrópodos  相似文献   
217.
对正在运行的大连台地磁数字记录和模拟记录,从地磁相对记录的三种变化磁场的类型进行了逐一对比分析,结果表明,虽然数字记录的整体方面明显优于模拟记录,但二者又各有其特点,数字记录代替模拟记录应该还有一段过渡的过程。  相似文献   
218.
学术论文的摘要是关系到论文能否被录用,发表及检索的重要因素。根据美国《化学文摘》收录环境科学论文的100篇摘要,从交际功能的角度对其收录前后进行语篇结构及语言特性进行分析,指出学术论文摘要应用于国际惯例接轨,并为学术论文摘要写作提供了重要的依据。  相似文献   
219.
We have recently proposed to use partial canonical ordinations to partition the variation of species abundance data into four additive components: environmental at a local scale, the spatial component of the environmental influence, pure spatial, and an undetermined fraction. By means of an example, we show how to use the information contained in these fractions to provide better insight into the data. In particular, the interpretation is assisted by separately mapping the various canonical axes and relating them to possible generating processes. We derive a general framework for the causal interpretation of the various fractions of this partition, which includes the environmental and the biotic control models, as well as historical dynamics.Daniel Borcard is research associate in animal ecology at Universite de Neuchâtel, Switzerland. He is interested in soil ecology, and presently working on fundamental and applied projects dealing with peat bog ecology and protection, community succession dynamics, as well as effects of agriculture on mite and insect communities. In order to develop the statistical tools necessary for these projects, he also works in collaboration with Pierre Legendre on modeling the spatial structure of ecological communities. $Pierre Legendre is professor of quantitative biology at Universite de Montreal. He is a former Killam Research Fellow (1989–91), and a member of the Royal Society of Canada since 1992. He is the author of some 100 refereed articles, over 250 papers presented at scientific meetings and research seminars, dealing with numerical ecology, community ecology, environmental assessment and spatial analysis, and textbooks (in French and English) on numerical ecology. During the past 5 years, he served as the Secretary-Treasurer of the International Federation of Classification Societies. *We thank Dr V.M. Behan-Pelletier, of Agriculture Canada, for her help in the identification of the Oribatid mites, and Mrs Lucie Fortin and Dr P. Neumann, Universite de Montreal, for their identifications of the Sphagnum species. This research was carried out during tenure of a Postdoctoral Fellowship of the Swiss National Foundation for Scientific Research by D. Borcard, and of a Killam Research Fellowship of the Canada Council by P. Legendre. It was also supported by NSERC grant No. A7738 to P. Legendre. This is contribution No. 392 of the Groupe d'Écologie des Eaux douccs, Universite de Montreal. The authors wish to dedicate this paper with gratitude to Mr Alain Vaudor, computer analyst in Pierre Legendre's laboratory, who has largely contributed to the planning of this research. Mr Vaudor passed away on October 31, 1991, at age 46. The package for multivariate and spatial data analysis that he has produced during his computer scientist career is available to researchers from P. Legendre.  相似文献   
220.
互联网的普及对推动环境科学技术发展起着很大作用 ,一方面 ,合理利用网络的资源可以使科研工作事半功倍 ;另一方面 ,互联网逐渐成为环境技术的推广应用、环保设备产品宣传和销售中的重要环节。本文介绍与环境科学技术相关的网络资源 ,包括文献检索、软件和环境科学讨论组、数据库、环保技术设备信息平台等  相似文献   
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