三江源区高寒草甸生物多样性影响因子分析——以称多县珍秦乡高寒草甸为例

文章以三江源区玉树州称多县珍秦乡围栏禁牧高寒草甸和围栏鼠害治理高寒草甸为研究对象,进行高寒草甸生物多样性影响因子的研究,研究结果表明:1.围栏禁牧和围栏(适牧)鼠害治理对提高草地群落生产力有一定效果;2.围栏禁牧对于草地生物多样性丰富度的增加效果不明显,围栏鼠害治理的同时进行适度放牧有利于草地生物多样性增加;3.高寒草甸草地生物多样性的主要限值因子是温度,而不是水份.     

黄腹角雉的栖息地研究

采用样方法对黄腹角雉栖息地的地理特征、植被组成、乔木层、灌木层以及地被植物的特点等方面进行了研究.以相似性指数分析、多样性分析、重要性分析等方法对冬、春、夏3季栖息地植被的特点作了分析.研究结果表明:黄腹角雉对栖息地坡度及坡向具有明显的选择性;栖息地植被层次结构明显,以壳斗科植物为优势的乔木层对决定栖息地植被的外貌和内部环境起着主导作用;冬、春、夏3季栖息地具有一定程度的相似性,同时又各具特点.     

城市公园栖息地特征对鸟类群落的影响：以上海市为例

上海作为中国城市化率最高的城市之一,是近40年来中国乃至世界城市化的缩影.近年来,随着上海生态城市建设进程的加快,公园数量和面积显著增加.城市公园作为野生动物栖息地的生态功能日益凸显.本研究选择上海市5个典型的大型城市公园,从景观尺度、微生境尺度和栖息地可利用度等3个尺度设置评价指标,利用对鸟类群落产生显著影响的公园面积、公园城市化指数、微生境复杂度、公园水体斑块密度等栖息地特征变量和鸟类群落对栖息地利用度进行公园生态功能评价.结果表明,公园作为鸟类栖息地的生态功能指数从高到低依次为海湾森林公园、上海植物园、世纪公园、共青森林公园和辰山植物园,数值与公园鸟类种类数排序一致.公园鸟类种类与城市化指数呈显著的负相关,城市化指数越高的区域,公园作为鸟类栖息地的生态功能越显著.在公园位置和面积确定的情况下,微生境复杂度是导致鸟类多样性差异的主要变量.5个公园中具有复杂微生境(含4个植被要素)的样方数量均不超过公园样方总数量的15%,具有简单微生境的样方数量占比为45%～75%,说明公园植被微生境营造以简单微生境为主,已成为制约鸟类多样性的限制因素之一.基于以上结论,在城市公园规划中应加强中心城区公园布局,在公园内部应配置复杂生境、增加水体密度和木本植物多样性、适当减少游客休憩区域及人工草皮面积,设置自然演替区以提高其作为野生动物栖息地的生态功能.     

荆州城市公园植物群落多样性研究

目的分析荆州城市公园植物群落物种多样性,为荆州及周边地区城市公园绿地规划和植物多样性保护提供参考依据.方法采用典型样方法,对荆州市7个城市公园选取235个样方开展植物多样性现状调查,分析其群落特征.结果荆州城市公园植物物种丰富,共有植物96科248属351种,植物群落优势种明显,植物多样性总体趋势依次为:灌木层,乔木层,草本层,但各公园之间又有差异,以中山公园和荆襄河湿地公园为最高;植物多样性指数大小依次为:综合公园,带状公园,专类公园.结论荆州城市公园植物群落物种组成较为丰富,物种多样性较高,但专类公园植物单一性较高,故选择适宜的植物品种,增加乡土植物的运用,提高群落的稳定性.     

甘肃省太子山国家级自然保护区生物多样性胁迫因素及保护对策

甘肃省太子山国家级自然保护区的建设与发展对黄河流域生态环境保护及西北地区生态安全屏障具有重要作用.然而,由于受各种因素的胁迫和干扰,保护区内的生物多样性丰富度降低,森林生态系统脆弱,野生动植物栖息地受到不同程度的影响.因此,文章根据保护区内生物多样性特点并通过调查分析,分别从冰暴雨雪、矿山开发、有害生物以及人为因素等方...     

大庆市生物多样性现状调查与生物安全

本文从野生动物区系特征和植物区系特征两个方面入手,调查研究了大庆市生物多样性的现状,阐述了大庆境内国家级、省级重点保护动植物物种保护情况,结果表明:大庆市共有国家一级保护动物6种,其中丹顶鹤及白鹤的数量稍有增加;国家二级保护动物38种,其中白枕鹤和灰鹤的数量均略有增加,而大鸨、小天鹅、大天鹅、角鸊鷉的数量却明显地减少了;省级重点保护动物21种.国家二级保护植物3种.其余物种数量相对稳定,并趋于平衡.另据调查,大庆没有外来动植物物种,也不存在因为生物技术而引起对生物多样性、生态环境和人体健康等方面的不利影响.     

大鸨的人工饲养

鸨科鸟类属于鹤形目,共计有9个属、25种、47个亚种。其中大鸨有5个种,它们是大鸨、阿拉伯大鸨、科里大鸨、印度大鸨和澳洲大鸨。分布在我国的大鸨又有两个亚种,即指名亚种(Otis tar-da tarda 分布在新疆的天山、喀什和吐鲁番)和普通亚种(O.t.dybowskii 繁殖分布区在东北的西部、内蒙;迁徙时路经辽宁和华北地区;在黄河、长江流域越冬)。野生大鸨的数量自十九世纪以来,一直呈明显下降的趋势,当前世界上大鸨的总数量只有3万只左右,其中我国有500只左右,     

栖息地破坏空间模式对集合种群动态的影响

利用元胞自动机模型,研究了栖息地破坏空间模式对集合种群动态的影响.结果表明:在破坏聚集度一定的情况下,栖息地面积的减少不利于强竞争物种的续存;在栖息地面积一定的情况下,栖息地破坏聚集度的增大有利于强竞争物种的续存;栖息地破坏比例对集合种群动态的影响更大,但栖息地破坏聚集度对集合种群物种多样性指数的影响更显著.在实际的生物保护中,可根据被保护的物种及其所在集合种群结构选择更加合理的土地开发、利用模式.     

青藏高原草地鼠害的生态释义及控制

首先详细阐述了鼠害涵义及对生态系统的危害.针对我国草原尤其青藏高原草地的严重鼠害状况,一方面,较系统地总结了鼠害对草原植被与土壤、生态系统稳定性,以及草地畜牧业生产的影响;另一方面,着重强调了草地中啮齿动物的生态功能——"生态系统工程师"及维持生物多样性的关键种作用.最后,提出了青藏高原草地鼠害的控制思路及途径,指出今后需要特别开展草地啮齿动物种群暴发,即鼠害发生的阈值的研究,并据此采取生态系统的适应性管理,以及其他人工控制技术来抑制鼠害发生.该文对于草地鼠害研究与控制具有重要的理论与实践意义.     

呼和浩特市市区春季鸟类群落结构及多样性研究

2004年4月对呼和浩特市市区不同类型城市化栖息地的鸟类分别进行了调查.共记录到鸟类32种,隶属于19科,9目.研究了不同类型栖息地中鸟类群落的多样性、均匀度、丰度、种间相遇机率等群落特征.调查结果显示:不同类型栖息地中,公园、苗圃的鸟类多样性和均匀度最高;商业区、交通占地的鸟类多样性和均匀度最低.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Design and analysis of generic LBS application developing platform

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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