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 379 毫秒
1.
以森林植被样地中乔木层树种的重要值为指标,采用纸条排队法、群落相似系数分类法、最近邻体法、组平均法对王二包自然保护区森林植被样地进行数量分类.结果表明:①4种分类结果基本相似,所调查的15个样地分为4个植被型8个群系;②区内常绿阔叶林类型基本处于稳定的顶极阶段,仅有少数样地受到人为干扰,群落表现出次生性质,如加强管理,群落将会恢复其原生稳定状态.  相似文献   

2.
青城山森林群落的数量分类   总被引:1,自引:1,他引:1  
以森林植被样地中乔木层树种的重要值为指标,采用群落相似系数分类法、最近邻体法、组平均法对青城前山森林植被样地进行数量分类。3种分类法的结果表明,所调查的11个森林植被的样地分为2个植被亚型5个群系,常绿阔叶林中的各个群系基本处于稳定阶段,仅有个别样地到人类的轻度干扰,一些阳生性的落叶成分侵入群落内,群落表现出明显的次生性质,但是,目前落叶成分在群落中缺乏更新幼苗,若加强森林管理,群落将会恢复其原生状态;杉木群系主要分布在人为影响较大的常绿阔叶林的林缘地带,由于许多常绿树种已进入群落的最高层造成遮荫,杉木在林内生长状况不良,群落最终将演替为常绿阔叶林。  相似文献   

3.
防城金花茶国家级自然保护区植物群落的聚类分析   总被引:2,自引:1,他引:1  
利用广西防城金花茶国家级自然保护区植物群落的样地调查资料, 以调查的17个样方中的55种乔木层植物的重要值为数据, 采用系统聚类法分析该保护区的植物群落特征.结果显示, 保护区内生境相似的植物群落较早得到合并,每个群落优势种或共优种明显,保护区植物群落可以划分为猴欢喜群系、血胶木 云贵山茉莉群系、水石梓 长叶柞木群系等11 个群系;保护区内除金花茶外,还分布有蒟蒻薯(Schizocapsa plantaginea)、锯叶竹节树(Carallia diplopetala)等其他珍稀植物甚至国家重点保护的野生植物资源.  相似文献   

4.
广西红树群落的数量分类   总被引:3,自引:0,他引:3       下载免费PDF全文
本文应用系统聚类分析方法,对广西红树群落进行了中级分类单位的划分。根据《中国植被》确定的分类原则、单位和系统,广西的红树群落可划分为6个群系:(1)白骨壤群系;(2)秋茄群系;(3)海漆群系;(4)木榄群系;(5)桐花树群系;(6)红海榄群系。同时,对这些群系特征作了简要的描述。  相似文献   

5.
据对南平市81处样地、24048m~2面积的森林各类型群落调查统计,共含维管束植物342种,分隶84科195属,单种和寡种属占总属数的92.3%.群落区系以壳斗、樟、山茶和茜草等科的属种以及热带、泛热带分布地理成分(分别占总属数的40.3%和26.0%)为主.优势树种有栲、木荷、石栎、润楠等属和马尾松.全市群落类型可分为10个植被型,含66个群系.植被具福建中亚热带南、北部亚地带过渡性区域特点.  相似文献   

6.
福建永定县的常绿阔叶林   总被引:3,自引:0,他引:3  
据对永定县常绿阔叶林的31处共3100m~2典型样地统计,共含维管束植物136种,分属43科86属.单种和两种属共占总属数的93%.群落区系以樟、壳斗、山茶和茜草等科以及热带,泛热带地理成分(分别占总属数的43.0%和31.4%)为主.优势树种有栲属多种、木荷、青冈、蕈树和马尾松.群落类型有槠林等12个群系并具中、南亚热带植被过渡性特点.树种年龄结构和乔灌木多样性分析表明,群落已趋向中一晚年发育期并开始转为恢复发展的前期阶段.  相似文献   

7.
福建建瓯市万木林罗浮栲群落特征的研究   总被引:2,自引:0,他引:2  
万木林地处福建省建瓯市,森林保护完好,罗浮栲群落是其分布面积最大的一个群落,无样地法群落调查表明,群落建群种为罗浮栲、木荷和栲.该群落结构复杂,上层乔木高大,有较明显的板状根,林下更新苗中上层优势种类仍有较大数量,群落层外植物相当发达,林内尚残留有少量的针叶、落叶树种.万木林罗浮栲群落是在阳性的针、阔混交林基础上演替而来的稳定的气候项极群落,具有典型的中亚热带地带性特征.  相似文献   

8.
采用对卫星影像图的分析和解译与实地样方、样线调查相结合的方法对海南岛的红树植物种类及红树植物群系进行了详细调查和研究.结果表明:海南岛最广布的本地红树植物种及最适生的引进种主要有20个科、25个属、38种,海南岛红树植物群系可分为11个群系类型.  相似文献   

9.
【目的】探究广西海岸潮间带草本植物区系和群落类型,为广西滨海湿地的保护与利用提供参考依据。【方法】在广西海岸东段、中段及西段潮间带选择典型的地段作为研究样地,各段设置5~8个样地,采取样方法进行调查,记录组成种类和群落类型,分析植物区系成分,编制群落分类系统。【结果】广西海岸潮间带草本植物群落物种共有29种,隶属10科18属,莎草科、禾本科、水鳖科和丝粉藻科的种类较多;根据中国湿地植被的分类系统和分类原则,结合广西海岸的具体情况,将广西海岸潮间带草本植物群落划分为4个植被型和16个群系。【结论】草本植物科、属的区系成分简单,具有很明显的热带性;潮间带草本植物群落结构简单;高潮区和河口区分布的群落较多。  相似文献   

10.
鄂西狮子关电站库区主要森林植被类型的数量分类   总被引:1,自引:0,他引:1  
在对鄂西狮子关电站库区森林的群落样方调查的基础上,研究其森林典型植物群系的特点及演替动态,并结合数量分类,将该地区主要森林植被类型-常绿阔叶林和针阔混北林划分为13个群系。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

19.
20.
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has  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