首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 171 毫秒
1.
陈宝冲THECHANGEOFTHEGENERALFORMANDTHETRANSPORTOFTHEWATER,LOADANDSALTABOUTTHENORTH-BRANCHOFTHECHANGJIANGRIVERMOUTH¥ChenBaochong(N...  相似文献   

2.
EVOLUTIONOFRAPIDSOFCREEKMOUTH-BARATGEZHOUBARESERVOIRANDTHEIMPACTSONNAVIGABLECHANNELINTHEUPPERREACHESOFTHECHANGJIANGRIVER¥LinC...  相似文献   

3.
ANANALYSISOFWATERRESOURCECHARACTERISTICSOFTHERIVERSINTHENORTHERNSLOPEOFTHEKUNLUNMOUNTAINSXuYoupeng(许有鹏);GaoYunjue(高蕴珏)(Depart...  相似文献   

4.
HONG KONG DIRECT INVESTMENT IN CHINA'S MAINLAND: A SPATIAL STUDY WITH SPECIAL REFERENCE TO THE LOCATIONAL BEHAVIOUR OF INVEST...  相似文献   

5.
罗洪,邓先瑞THEVERTICALDISTRIBUTIONOFAGROTOPOCLIMATICRESOURCESINTHEWARMSECTORSOFTHETHREEGORGESAREAOFTHECHANGJIANGRIVER¥DengXianrui;...  相似文献   

6.
THE PRELIMINARY STUDY ON POSSIBLE SCENARIOS OF FLOOD AND DROUGHT IN CHINA IN THE CASE OF GLOBAL WARMING ChenJiaqi(陈家其)(Nanjin...  相似文献   

7.
STUDYONGENESISOFHYDROCHEMICALPROPERTYOFFLUIDINCLUSIONSOFMINERALSZhangxiangxunDuShengbao(No.1GeologicalPartyofGuangxi,Guilin)(...  相似文献   

8.
(翁齐浩)THERELATIONSHIPBETWEENTHEENVIRONMENTALCHANGEOFTHEZHUJIANGRIVERDELTAINHOLOCENEANDITSCULTURALORIGINSANDPROPAGATION¥WengQih...  相似文献   

9.
IMPACTOFFUTURESEALEVELRISEONFLOODANDWATERLOGGINGDISASTERSINLIXIAHEREGION许朋柱IMPACTOFFUTURESEALEVELRISEONFLOODANDWATERLOGGINGDI...  相似文献   

10.
THEPOSITIONANDROLEOFWUHANCITYINTHEREGIONALECONOMICMACROSTRATEGIESOFCHINA①LiuMiaolong(刘妙龙)DeptartmentofSurveyingandGeoinforma...  相似文献   

11.
研究剖面位于洛川源北部的富县县城东郊。剖面由第一层古土壤(S_1)、马兰黄土(L_1)和全新世古土壤(S_0)组成。孢粉分析结果表明,黄土地层中孢粉非常丰富,为恢复古植被与古气候提供了可靠依据。S_1的植被是以榛、菊、蒿为主的疏林草原,有亚热带树种出现,反映了末次冰期的温湿气候。L_1时主要为菊、蒿干草原,气候冷干,其间有四次乔木增多期,反映了末次间冰期中有四次间冰阶的相对温湿气候波动。近代耕土中为以松、藜、中华卷柏为主的森林草原,反映了全新世某个时期比较温凉干旱的气候。  相似文献   

12.
Most world natural heritage sites are designated partly by reason of their prominent aesthetic values in accordance with Article Ⅶ of World Natural Heritage Convention.In this paper, the aesthetic values of Kanas National Nature Reserve, which has potential for such designation, was analyzed quantitatively using scenic beauty estimation(SBE).The landscapes of 19 representative scenic spots in the Kanas National Nature Reserve in summer and autumn were selected as the objects of evaluation.The contributions of different landscape factors to the aesthetic value of the Kanas National Nature Reserve were revealed using a multivariate quantitative model.The main factors affecting the aesthetic value were waterscapes, vegetation, mountains, folk culture and the tourist environment.The t-test and F-test results are extremely significant.According to the results, some suggestions were given for conserving the landscapes in the Kanas National Nature Reserve.  相似文献   

13.
Relationships between topography,soil properties and the distribution of plant communities on two different rocky hillsides are examined in two subtropical karst forests in the Maolan National Natural Reserve,southwestern China.Surveys of two 1-ha permanent plots at each forest,and measurements of four topographic and thirteen edaphic factors on the slopes were performed.Twoway Indicator Species Analysis(TWINSPAN) and Detrended Canonical Correspondence Analysis(DCCA) were used for the classification of plant communities and for vegetation ordination with environmental variables.One hundred 10m×10m quadrats in each plot were classified into four plant community types.A clear altitudinal gradient suggested that elevation was important in community differentiation.The topography and soil explained 51.06% and 54.69% of the variability of the distribution of plant species in the two forest plots,respectively,indicating both topographic factors(eg.elevation,slope and rock-bareness rate) and edaphic factors(e.g.total P,K and exchangeable Ca) were the important drivers of the distribution of woody plant species in subtropical karst forest.However,our results suggested that topographical factors were more important than edaphic ones in affecting local plant distribution on steep slopes with extensive rock outcrops,while edaphic factors were more influential on gentle slope and relatively thick soil over rock in subtropical karst forest.Understanding relationships between vegetation and environmental factors in karst forest ecosystems would enable us to apply these findings in vegetation management strategies and restoration of forest communities.  相似文献   

14.
1 INTRODUCTIONOne of the 7 key plans of IGBP (International Geo-Biosphere Project) is the PAGES (Past Global Changes), of which the relation of mutual influence of mankind and natural environmental changes during historic period has attracted great attentions over the world (CHEN,1992; Committee of National Natural Science Foundation of China, 1995). Due to the atrocious natural conditions, study of this issues are much more backward in southern Xinjiang. So to investigate and…  相似文献   

15.
金钟山国家级自然保护区黑颈长尾雉生境适宜性评价   总被引:1,自引:0,他引:1  
为加强对珍稀动物黑颈长尾雉(Syrmaticus humiae)的保护,本研究以广西金钟山国家级自然保护区的黑颈长尾雉野外实地调查数据为基础,在地理信息系统(GIS)技术支持下,以植被类型、植被覆盖度、海拔和坡度为评价因子,采用生境适宜性评价模型,对黑颈长尾雉潜在生境的适宜性进行了评价。研究结果表明:(1) 黑颈长尾雉最适宜的生境是海拔1000~1850 m、坡度为5~25 o、盖度大于70%的落叶阔叶林,这些区域应该成为重点保护的生境;(2) 保护区内黑颈长尾雉分布的生境类型有25种,鉴于保护的有效性和成本,选择面积占主导的15种生境类型为潜在生境,其中,54.31%的潜在生境分布在核心区内,15.75%分布在缓冲区,29.94%分布在实验区;(3) 生境适宜性评价结果表明,保护区适宜栖息生境的面积达74 km2,约占保护区总面积的36.30%。最后,基于黑颈长尾雉在金钟山自然保护区的生境适宜性研究范围提出了相应的保护对策。  相似文献   

16.
Nanda Devi Biosphere Reserve(NDBR) was declared as the first Himalayan Biosphere Reserve owing to its unique biological and cultural wealth. Its core zones, Nanda Devi National Park and Valley of Flowers National Park, are a UNESCO World Natural Heritage Site. In spite of lying at a high altitude, interplay of factors such as unique geographical location, climate, topography and wide altitudinal variations have endowed NDBR with a rich and diverse flora. Proportionately high percentage of endemic and near endemic plants makes NDBR a very important protected area from conservation point of view. However, its floristic wealth is facing unprecedented threats in the form of climate change and growing anthropogenic pressure. Hence, a need was felt to assess the directionality, quality and sufficiency of past and ongoing research for the conservation of floral and ethnobotanical wealth of NDBR in the absence of any such previous attempt. Based on an extensive review of more than 150 plant studies on NDBR, this communication provides a detailed account of the current state of knowledge and information gaps on flora, vegetation ecology, rare, endangered, threatened(RET) and endemic plants and ethnobotany. Priority research areas and management measures are discussed for the conservation of its unique floral wealth. Incomplete floral inventorization, lack of biodiversity monitoring, meagre studies on lower plant groups, population status of medicinal plants, habitat assessment of threatened taxa and geo-spatial analysis of alpine vegetation were identified as areas of immediate concern.  相似文献   

17.
Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in higher plants of alpine region.Herein, hydrocarbon leaf wax components of Salix oritrepha, which flourish in Nianbaoyeze Mountains in eastern Tibetan Plateau were fully discussed. The n-alkane distribution in leaves ranges from n-C_(21) to nC_(29) with maxima at n-C_(25), which were entirely different with Salix taxa displayed in previous surveys in non-alpine regions. The unusual even carbon nalkenes from n-C_(22:1) to n-C_(30:1), which were thought to appear only in aquatic organisms, were firstly reported in an alpine plant. Additionally, iso-(2-methyl) alkanes, ranging from i-C_(23) to i-C_(29) with maxima at i-C_(25), which have been commonly reported in microorganisms, were also identified in an alpine plant for the first time. Unusual hydrocarbon distribution detected in Salix oritrepha leaf from Nianbaoyeze Mountains is most likely due to the extreme environment in such alpine region.  相似文献   

18.
This study examined the temporal variation of the Normalized Difference Vegetation Index (NDVI) and its relationship with climatic factors in the Changbai Mountain Natural Reserve (CMNR) during 2000-2009.The results showed as follows.The average NDVI values increased at a rate of 0.0024 year-1.The increase rate differed with vegetation types,such as 0.0034 year-1 for forest and 0.0017 year-1 for tundra.Trend analyses revealed a consistent NDVI increase at the start and end of the growing season but little variation or decrease observed in July during the study period.The NDVI in CMNR showed a stronger correlation with temperature than with precipitation,especially in spring and autumn.A stronger correlation was observed between NDVI and temperature in the tundra zone (2,000-2,600m) than in the coniferous forest (1,100-1,700m) and Korean pine-broadleaved mixed forest (700-1,100m) zones.The results indicate that vegetation at higher elevations is more sensitive to temperature change.NDVI variation had a strong correlation with temperature change (r=0.7311,p<0.01) but less significant correlation with precipitation change.The result indicates that temperature can serve as a main indicator of vegetation sensitivity in the CMNR.  相似文献   

19.
通过对延长油矿延223井晚古生代孢粉组合研究以及古植被的恢复,探讨了该区晚古生代孢粉植物化石组合的地层学和古气候意义。根据孢粉化石主要属种的时代分布及其在各样品中百分含量的规律性变化,自下而上建立了3个孢粉组合:Gulisporites cochlearius-Laevigatosporites minimus组合、Sinulatisporites-Florinites组合和Lueckeisporites permianus-Platysaccus radialis组合。根据对划分孢粉组合的特征分析,通过与邻区及华北地区晚古生代孢粉组合的对比,探讨了孢粉组合的时代意义。通过孢粉组合,推测了相应时期的古植被类型,并与前人在相同地质时期所建立的大植物化石带进行了对比,分析了各地质时期植被的兴起、发展、繁盛以及衰退绝灭的历史过程,研究区二叠纪植物群属于典型的华夏植物群,反映了一种温暖潮湿的热带雨林气候,二叠纪晚期随着松柏类植物所占比例的增加,气候有变干旱的趋势。  相似文献   

20.
晚始新世-渐新世期间南大洋及其周边地区的古气候响应研究有助于我们更好地认识地质历史上的重大气候转型机制和预测未来地球系统对于气候突变的响应, 然而迄今为止, 仍缺乏对该区域周边陆地的古气候响应研究。基于国际大洋发现计划(IODP)369航次U1516站位深海沉积物的年龄框架以及常量、微量和稀土元素组成, 确定了该沉积物主要来源于澳大利亚西南部大陆, 进而重建了构造时间尺度上物源区的化学风化历史。在此基础上, 探讨了晚始新世-渐新世气候转折期南大洋周边大陆的古气候演化过程及其对于全球气候变化和区域古地理改变的响应。在始新世-渐新世转折期[34.1, 33.6) Ma和[31.3, 29.8) Ma期间, 物源区的古气候主要受控于邻近区域古地理格局重大变化的影响, 具体表现为气候条件趋于干冷和陆表化学风化强度降低的特征。在[33.6, 31.3) Ma和[29.8, 25.2] Ma期间, 物源区的古气候则主要响应全球气候的变化, 在前一阶段由干冷向湿热转变, 而陆表化学风化强度相应增高;在后一阶段,气候保持在相对稳定的干冷状态,陆表化学风化强度也较弱。   相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号