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1.
对吉林省左家自然保护区杂木林、蒙古栎+黑桦林和花曲柳-榛灌丛次生林的大型土壤动物进行研究,共获大型土壤动物2522只,分别隶属3门8纲25目。三种生境大型土壤动物群落水平结构表现为类群数相似,但土壤动物组成上存在明显差异,共同优势类群均为蚁科。大型土壤动物群落垂直结构表现为表聚性,花曲柳-榛灌丛的表聚性要高于杂木林和蒙古栎+黑桦林。蒙古栎+黑桦林和杂木林大型土壤动物相似性程度极高,与花曲柳-榛灌丛为中等相似;蒙古栎+黑桦林和花曲柳-榛灌丛大型土壤动物多样性相似,与杂木林多样性存在一定差异,表现为优势度指数高,均匀度、丰富度和多样性指数低。  相似文献   

2.
对吉林省左家自然保护区杂木林、蒙古栎+黑桦林和花曲柳-榛灌丛次生林的大型土壤动物进行研究,共获大型土壤动物2522只,分别隶属3门8纲25目。三种生境大型土壤动物群落水平结构表现为类群数相似,但土壤动物组成上存在明显差异,共同优势类群均为蚁科。大型土壤动物群落垂直结构表现为表聚性,花曲柳-榛灌丛的表聚性要高于杂木林和蒙古栎+黑桦林。蒙古栎+黑桦林和杂木林大型土壤动物相似性程度极高,与花曲柳-榛灌丛为中等相似;蒙古栎+黑桦林和花曲柳-榛灌丛大型土壤动物多样性相似,与杂木林多样性存在一定差异,表现为优势度指数高,均匀度、丰富度和多样性指数低。  相似文献   

3.
为了掌握成都市郊区土壤动物群落特征及不同土地利用方式对土壤动物群落的影响,2008年10月对成都市郊区的绿化林、农田和莱地内的土壤动物进行了调查.共捕获大型土壤动物213只,隶属于2门6纲10类(目),优势类群为大蚓类(Macrodrilc oligochaetes)和小蚓类(Microdrilc oligochaetes);中小型土壤动物1118只,隶属4门7纲10类(目),优势类群为弹尾目(Diplura)、线虫类(Nematode)和线蚓类(Enchytraeidae);大型和中小型土壤动物类群和个体数的大小顺序均为菜地〉林地〉农田,但仅有中小型土壤动物的个体数有显著差异(P〈0.05);大型土壤动物群落间的多样性差异不显著(P〉0.05),中小型的差异显著(P〈0.05);大型土壤动物群落间相似性低于中小型;林地和菜地土壤动物垂直分布的表聚性高于农田,大型土壤动物的表聚性高于中小型.研究结果表明,不同土地利用方式对大型和中小土壤动物群落的影响不同.  相似文献   

4.
采用样方法,对松嫩草地和小兴安岭森林土壤动物群落进行了比较研究.结果表明:两个研究区10个生境土壤动物个体数量和类群组成具有显著差异.松嫩草地优势类群为辐螨亚目、蚁科和长蝽科,小兴安岭森林为甲螨亚目、线蚓科和节跳虫科.常见类群松嫩草地和小兴安岭森林分别为12和11类,仅革螨亚目和双翅目幼虫为两研究区共有;稀有类群分别为53和50类,仅19类为共有.松嫩草地和小兴安岭森林土壤动物多样性指数没有明显区别.对应分析结果显示,不同生境土壤动物群落组成反映了生境环境条件的差异.森林生境土壤动物群落结构较为相似,与草地生境差异较大.  相似文献   

5.
内蒙古中部农牧交错区中小型土壤动物群落特征研究   总被引:3,自引:0,他引:3  
在内蒙古中部农牧交错区选择农田、退耕地、人工林地和荒漠草原4种生境类型,对中小型土壤动物群落特征进行了研究.结果表明,农牧交错区中小型土壤动物优势类群为线虫(Namatoda),常见类群为螨类(Acarina)和弹尾类(Collembola).从4种生境中小型土壤动物群落特征的对比分析看,退耕地的丰富度较高,多样性较大,荒漠草原的各种指数相对较低.从中小型土壤动物的垂直分布看,个体数和类群数随土层深度增加而递减,表聚性明显.不同生境中小型土壤动物个体数和类群数随季节变化具有一定的差异性.春季,人工林地个体数较多,退耕地个体数较少,农田类群数较多.夏季,农田个体数较多,荒漠草原个体数较少,退耕地类群数较多.秋季,人工林地个体数较多.农田个体数较少.人工林地类群数较多,退耕地类群数较少.  相似文献   

6.
大型土壤动物在城市土壤污染指示作用的初步研究   总被引:1,自引:0,他引:1  
本文对乌鲁木齐市南部林地、公园、居住区、耕地及草地等典型土地利用生境进行大型土壤动物调查,采用手拣法野外采集大型土壤动物,应用个体密度、类群数、Shannon-Wiener多样性指数、Pielou.均匀度指数、Simpson优势度指数及Margalef丰富度指数等指标,研究土地利用变化对大型土壤动物群落特征的影响。研究结果表明,研究区共捕获大型土壤动物517只,分别录属于三门七纲十七目64科。不同土地利用生境大型土壤动物个体密度、类群数和多样性等指标存在差异,其中耕地和草地土壤动物的类群数和个体密度明显碱少;植物群落类型对大型土壤动物群落特征有一定影响;大型土壤动物个体密度和类群数主要集中分布在地表0~5cm土壤层,生境地表植被对土壤动物群落的类群数,个体密度及多样性指标等的影响明显.此外,地表植被、不同土地利用类型、土壤污染程度是引起大型土壤动物群落结构变化的主要因素.  相似文献   

7.
庐山土壤动物群落结构研究   总被引:4,自引:0,他引:4  
通过对庐山6种生境中土壤动物群落的定位调查,共获得土壤动物33类,分别隶属于4门11纲23目,其中线虫类和弹尾类等属于优势类群。土壤动物在土体中的表聚性强,绝大部分集中分布于A层(0—5cm)。对Ⅰ、Ⅱ、Ⅴ、Ⅵ4种不同生境间土壤动物群落的种类组成、数量分布、多样性以及相似性进行的对比分析表明:生境条件越优越,土壤动物的种类越丰富(如混交林和黄山松林);土壤动物群落的物种丰富度越大、个体数量分布越均匀,群落多样性越高(表现为H指数和DIC指数均是林下(阳坡)灌木草本发达、土壤有机质含量丰富、生境异质性高的黄山松林和混交林高于灌草丛和柳杉林)生境条件较差的灌草丛与柳杉林最相似,相似性最低的是混交林与灌草丛。  相似文献   

8.
对长白山区高速公路边坡的中小型土壤动物进行了调查,探讨了人工植被恢复后公路边坡土壤动物的群落特征.研究区内共捕获中小型土壤动物32类,4 807只.结果表明:不同生境土壤动物群落类群数和个体数量的多样性特征存在差异,阳坡土壤动物的类群数大于阴坡,而个体数量小于阴坡;土壤动物群落个体和类群主要集中分布在0~5 cm土壤层...  相似文献   

9.
通过对泰山地区土壤动物群落结构的研究发现,螨类是该地区的主要优势类群,占动物总数量的76.30%;另一优势类群--跳虫仅占13.63%.土壤动物的季节消长与土壤温度呈负相关,土壤动物的数量与土壤含水量在一定范围内呈正相关.土壤动物具有表聚性,但不同生境、不同季节有很大变化.群落的多样性指数较低,平均不足最大多样性指数的1/3.两种百分比相似系数(相似性系数和百分比相似性系数)的聚类结果差异明显,优势类群的数量对聚类的结果影响很大,影响群落数量分布的因素均可影响聚类结果.  相似文献   

10.
以长白山地不同干扰程度下的次生针阔混交林、次生阔叶林以及农田为研究对象,探讨了长白山地不同干扰程度下森林土壤动物的群落特征.结果表明:长白山地森林土壤动物的分布因干扰程度的不同而存在差异,随干扰程度的增强,土壤动物群落的个体密度、类群数及多样性均呈现减少的趋势.冗余分析表明土壤有机质、全氮、速效氮、速效磷、土壤温度和土壤含水量对土壤动物群落有重要的影响,多数土壤动物群落与土壤有机质、全氮、速效氮和土壤含水量呈正相关关系,而与全钾、速效磷、锰和土壤温度呈负相关关系.  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.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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   

16.
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   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
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   

19.
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   

20.
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   

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