退化草原轻耙处理过程中植物种多样性变化的研究   总被引：10，自引：3，他引：7  

宝音陶格涛  刘美玲 《中国沙漠》2003,23(4):441-445

利用多年样方资料的统计分析,对退化草原群落轻耙处理后恢复过程中的生物多样性变化规律及引起这些变化的主要植物种群进行研究,结果表明:在退化群落耙地恢复过程中,整个群落的物种丰富度变化不大,物种分布的均匀性指数随演替过程呈现波动下降的趋势,多样性指数也呈现波动下降的趋势,恢复后期有所升高,且物种分布的均匀性是造成物种多样性指数变化的主要原因。羊草(Leymus chinensis)的密度和生物量的变化与多样性指数具有极显著的负相关关系。冷蒿(Aartemisia frigida)、洽草(Koeleria cristata)的密度和生物量与多样性指数具有极显著的正相关关系。隐子草(Cleistogenes squarrosa)、变蒿(A.commutata)的密度与多样性指数具有极显著的正相关关系。多样性指数与耙地处理后的恢复年限(11 a间)的关系可表示为:以密度为指标的多样性指数D_n=3.579-0.665Lnx(r=-0.9185);以生物量为指标的多样性指数D_w=4.4-0.7696Lnx(r=0.8667)。  相似文献   

贵州洞穴螺类的物种多样性及分布初步研究   总被引：5，自引：0，他引：5  

黎道洪  陈德牛  罗泰昌  罗蓉  彭涛 《中国岩溶》2003,22(3):212-218

2001年1月至2002年8月对贵州的龙洞、和尚洞、竹林洞及织金洞等50余个洞穴内的螺类进行了调查,共采集标本1306号,经鉴定和分类,隶属1纲2目15科108种, 其中有4个新种。不难看出,贵州洞穴螺类的物种丰富度较高,并具有从有光带到弱光带呈下降趋势;从物种的丰度来看,在有光带最高,弱光带和黑暗带则无明显的差异。优势种不明显。从水平分布看, 分布的种类和数量最多的均是有光带; 从空间分布看, 主要分布于洞底。此外, 还对螺类适应洞穴生活的特征及保护作了初步分析。   相似文献   

煤的镜质体荧光强度与煤岩参数的关系     

叶道敏 《煤田地质与勘探》2004,32(1):4-5

研究了煤的镜质体性质与煤岩参数的关系,表明镜质体的荧光强度I₆₅₀与镜质体的性质关系密切,这对表征等变质煤镜质体性质的差异极其重要。   相似文献   

Diversity history of Ordovician graptolites and its relationship with environmental change     

Zhang YuanDong  Chen Xu 《中国科学D辑(英文版)》2008,51(2):161-171

Statistical analysis based on global data indicated that the planktonic graptolites presented a distinguished pattern from that of benthic communities during the great Ordovician biodiversification. The graptolites started to diversify from the beginning of Ordovician and reached an acme in the early Middle Ordovician, but subsequently underwent a steady decline to the end of Ordovician. During the Ordovician, many clades of the graptolites made their originations, flourishing and replacements. However, in different regions and distinct environments across the world, graptolites may presumably display distinct patterns of radiation and evolution, a hypothesis to be tested. Herein a study of the graptolite diversity in the Early to Middle Ordovician in the Upper Yangtze Region (Platform) and Jiangnan Region (Slope), South China, is conducted. The results indicate that graptolites underwent a remarkable increase in both regions, but with distinct magnitude, scope, process and patterns. The diversification of graptolites in the Upper Yangtze Region, though less prominent, is divided into four stages and includes two peaks. In the Jiangnan Region, the graptolite diversification is far more prominent and includes three stages and one peak. Based on the distinct diversity histories and composition of graptolites in the two representative regions, a 'deep-water origin and shallow-water dispersal' model is proposed for the Ordovician graptolite faunas. According to the model, the major graptolite faunas of Ordovician originated in the deep-water region on the continental slope, the source of the graptolite novelties, and subsequently spread into shallow-water region on the shelf. Besides, we also conduct a comparison study of the Ordovician graptolite diversity in South China and other major regions. The results display that the graptolites diversified globally in the Early and Middle Ordovician. At the beginning of Ordovician, graptolites underwent a significant ecological innovation of graptolites: planktonic forms were derived from their benthic ancestors. This derivation resulted in the great guild expansion of graptolites. In late Early Ordovician (Floian), the global expansion of graptolites commenced. From the Floian to the end of Middle Ordovician, the graptolites diversity increased remarkably and displayed three peaks for all the regions. However, the peaks are somewhat distinct in magnitude and timing among regions. The Darriwilian peak is prominent in both South China and Baltic region, but inconspicuous in Australasia. No close relationship between the graptolite diversification and the palaeolatitudes are supported herein. Instead, the graptolite diversification seems to coincide with the global sea-level rises, suggesting a possible intrinsic relationship between them.  相似文献   

旅游对武夷山景区灌木林物种多样性及其根系生物量的影响     

文雅香  钟全林  夏金林  肖海燕  张晓芳 《地理科学进展》2009,28(1)

采用对比样方调查法对武夷山旅游区内的武夷宫、大红袍、龙川瀑布和天游峰4个典型景区灌木林物种多样性指数、均匀度和丰富度指数、植被盖度及根系生物量等指标进行了调查与分析,并对旅游活动对灌木林的影响机理进行了探讨.结果表明:旅游活动对景区灌木林物种多样性指数具有显著影响(Shannon-weiner均匀度指数除外),对林下根系生物量虽有影响,但影响不显著.干扰区的灌木林物种多样性指数、盖度、总根系及细根生物量均小于非干扰区.4景区灌木林的干扰变化率依次为:物种多样性指数为武夷宫>天游峰>龙川瀑布>大红袍,盖度为大红袍>武夷宫>天游峰>龙川瀑布.总根系生物量为天游峰>大红袍>龙川瀑布>武夷宫,细根生物量为天游峰>龙川瀑布>武夷宫>大红袍.  相似文献   

Efficiency, Equity and Effect: a case study on virtual water consumption characteristics     

HaiYang Shang  KeGong Chen  ZhongMin Xu  GarlandRenn Sam 《寒旱区科学》2009,1(2):0170-0176

Scarcity of water is the key factor restricting the growth of social economy.The virtual water theory provides a new way to solve the problem of water scarcity.For this paper,we have calculated the virtual water consumption of each household,grouped by income,of Gansu province for 1992-2005.Then we advanced the indicator of virtual water with per-unit-of-consumption expenditure to analyze the efficiency of virtual water consumption.Additionally,we recurred to the diversity theory advanced by Ulanowicz,which is broadly employed by ecologists and biologists,to analyze the characteristics of virtual water consumption.As a result,the virtual water consumption of each group decreased yearly from 1992 to 2005,on the whole;decreasing proceeded slower during the period of 1992-1997 than during 1998-2005.Per-unit-consumption expenditure of virtual water for each group represents the same characteristics,on the whole,as virtual water consumption.The largest variation of this indicator exists in the group of the lowest income,which ranges from 1.58 to 0.18 m3/Yuan.yr;whereas the least exists in the highest income group,which is 0.58 to 0.07 m3/Yuan.yr.The virtual diversity indicator increased year by year,and the change of this indicator in 1992-1997 was more obvious than in 1998-2005.Finally,from this study we find that,in view of virtual water,we can save water by means of changing consumption patterns and increasing consumption diversity,but without degrading the quality of living and reducing the demands of living.When the problem of water scarcity becomes more and more serious in Gansu of China,this suggestion becomes more and more important.The consumption,the role of guiding production produce,is very important.An unsustainable consumption pattern is the main factor causing the deterioration of the world environment,especially in a developing country.The sustainable consumption is the only way to develop human beings and achieve the economical sustainable economics.  相似文献   

贵州香纸沟岩溶藓类附生水生原生动物群落生态特征   总被引：1，自引：0，他引：1  

王智慧  张朝晖  李建华 《中国岩溶》2007,26(3):249-254

岩溶藓类是一种独特的生态系统类型,维持了丰富的附生水生原生动物群落多样性。2006年11月26日至2007年1月26日, 对贵阳市香纸沟岩溶沉积环境中8种藓类附生水生原生动物群落进行了野外生态调查,采集样品和标本48份。经室内对附生水生原生动物培养、分离和鉴定, 揭示了该区岩溶藓类附生水生原生动物群落具有下述特征: ( 1)水生原生动物群落物种组成含24科26属36种。( 2)水生原生动物群落含6个功能营养群。其中,原生动物光合营养群( P群, Photosy nthetic auto tro phs) , 占总数的25% ; 细菌取食者群( B群, Bactivores detritivores) , 占总数的44. 44% ; 腐生营养类群( S群, Saprotrophs) ,占总数的2. 78% ;食藻者类群( A群, Algivores) ,占总数的11. 11% ; 非选择性杂食者群( N 群,Nonselective omnivores) , 占总数的11. 11% ;食肉者群( R群, Raptor s) ,占总数的5. 56%。( 3)根据岩溶水流、基质和藓类植物特征,划分该区附生水生原生动物生态群落为4个类型和8个亚类型。   相似文献   

砾间接触氧化反应器中细菌多样性评价     

林山杉  金玉花  付丽丽 《地理科学》2007,27(6):849-852

采用分子生物学手段,通过构建16S rDNA基因文库,对新型剩余污泥减量化处理系统——砾间接触氧化反应器中细菌多样性进行了系统发育分析;通过多样性指数、丰富度指数、均匀度指数及优势度指数,对细菌多样性及优势菌种富集状况进行了系统评价。结果表明:共有80个克隆子,分别代表29个OTU,用于系统细菌分析。其中,石球外膜46个克隆子(17个OTU),石球内泥34个克隆子(12个OTU)。生物膜中细菌多样性及优势菌种富集状况均好于孔隙内泥中的细菌。  相似文献   

荒漠河岸植被的受损过程与受损机理分析   总被引：9，自引：0，他引：9  

刘加珍  陈亚宁  李卫红  陈永金 《地理学报》2006,61(9):946-956

以塔里木河多年平均地下水位数据为依据,将地下水位划分为6个环境梯度,各梯度上6次重复采集植被样地数据。从物种多样性、植被盖度与群落类型等几方面分析了植被的受损过程,以及导致此过程的受损机理。结果表明：(1) 草本植物丰富度受损发生在地下水埋深大于4 m,而木本植物丰富度受损发生在地下水埋深大于8 m。(2) 植被盖度减少始于草本植物盖度受损,与群落多样性受损的临界地下水位相同,发生在地下水埋深大于4 m;在地下水埋深大于6 m之后,植被盖度不断减少则是由木本植物盖度的减少所引起。(3) 群落类型受损体现在芦苇群落和胡杨林群落的结构与类型变化上,芦苇群落的衰退演变出现了优势种的更替,而胡杨林群落中优势种的优势地位没有变化。(4) 此受损过程是由荒漠河岸生态系统脆弱的生态基质和外界干扰共同作用的结果,起因于人口的增加、需求的增长。植被退化是人类干扰作用于植被赖以生存的环境主导因子所致。在生态受损过程中,植物功能型差异与所承受的干扰强度差异对植被退化的程度有一定影响。  相似文献   

Identifying the pollen of an extinct spruce species in the Late Quaternary sediments of the Tunica Hills region,south‐eastern United States          下载免费PDF全文

L. MANDER  J. RODRIGUEZ  P. G. MUELLER  S. T. JACKSON  S. W. PUNYASENA 《第四纪科学杂志》2014,29(7):711-721

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