安徽荒漠植被的多元分析

应用数量分类和排序方法分析了安西砾石戈壁荒漠植被、并应用逐步回归分析方法确定了群落和环境因素的关系方程。结果表明,该区砾石戈壁荒漠植被可分为６个主要群落类型。这些群落类型与土壤总含盐量、氯化物含量、硫酸盐含量及年降水量有密切的关系。     

科尔沁沙地植物群落分布与土壤特性关系的DCA、CCA及DCCA分析

基于科尔沁沙地流动沙丘、半固定沙丘、固定沙丘和草地群落类型24个样地的野外调查,选取11个土壤因子,应用除趋势对应分析法(DCA)、典范对应分析法(CCA)和除趋势典范对应分析法(DCCA)分析沙地植物群落分布与环境因子的关系。结果表明:DCA、CCA和DCCA的物种排序第1轴代表的土壤特性梯度一致,其解释总方差超过33%,即土壤碳氮含量、p H、电导率、容重、粘粉粒等共同的梯度决定了群落生境的变化,影响着沙地植物群落类型的分布格局;3种排序法的物种排序第2轴土壤因子的相关性有较大差异,DCA第2轴仅与土壤细沙含量显著正相关,CCA第2轴与土壤碳氮比和细沙含量显著负相关,DCCA第2轴与土壤碳氮比和细沙含量显著正相关,而与粗沙含量显著负相关。Shannon指数和Simpson指数分别与DCA、CCA和DCCA前2个排序轴存在显著二元线性关系,且Shannon指数的拟合程度好于Simpson指数。3种排序分析方法中,CCA物种排序前两轴的累计解释方差(58.6%)高于DCA和DCCA,因此CCA排序法更适合于沙地植被分布格局研究及其环境的解释。     

安太堡矿区人工植被在恢复过程中的生态关系

采用TWINSPAN、DCA和DCCA,从植物种、植物群落与环境因子关系方面对平朔安太堡矿区的人工植被在恢复过程中的生态关系进行了研究.结果表明,将63个样方划分为12个群落类型,反映了植物群落与环境梯度之间的关系,并列举了各群落的特征.DCA排序图明显反映出排序轴的生态意义,随着复垦时间的增加,土壤含水量也不断升高.DCCA排序进一步表明了土壤有机质含量是所有因子中对植物群落发展起决定性作用的主要环境因素.     

黄河河口盐沼植被分布、多样性与土壤化学因子的相关关系

以黄河河口盐沼实地调查的67个样地19个植物种的重要值,运用双向指示种分析将黄河河口盐沼植被分为柽柳-翅碱蓬+补血草+碱蓬群落、翅碱蓬群落、柽柳-芦苇+翅碱蓬群落、芦苇群落、穗状狐尾藻+芦苇群落和旱柳-芦苇+荻群落.利用典范对应分析(CCA)分析了土壤盐分、pH、Na+、K+、Ca2+、Mg2+、Cl-、全氮、全磷、全碳、有机质等11个土壤化学因子与黄河河口盐沼植被分布的相关关系.CCA排序结果表明,土壤盐分和土壤pH是影响黄河河口盐沼植被分布的主要土壤化学因子.CCA排序第一轴与土壤盐分呈显著正相关关系(P<0.001),第二轴主要和土壤pH呈显著负相关关系(P<0.001).柽柳-翅碱蓬+补血草+碱蓬群落排列于排序图的右上部,与生境土壤中高含盐量及中等pH相对应,穗状狐尾藻+芦苇群落和芦苇群落分布于第一排序轴的最左端,主要与土壤低含盐量相关,翅碱蓬群落位于第二排序轴的下侧, 与较高的土壤pH相关,柽柳-芦苇+翅碱蓬群落和旱柳-芦苇+荻群落,土壤pH和盐分均较低.通过物种丰富度R、香农维纳多样性H′、物种均匀度E等指数与土壤化学因子的相关分析,发现黄河河口盐沼植物物种多样性与土壤盐分没有呈现出与土壤盐分很好的负相关关系,物种丰富度R、香农维纳多样性H′、物种均匀度E均与土壤盐分呈现显著正相关关系;R、H′与土壤pH呈现出十分显著的负相关关系; R、H′与土壤Ca2+、Mg2+含量呈现极为显著正相关关系.     

三江源区高寒草甸土壤与草地退化关系冗余分析

通过在高寒草甸设置研究样地、进行植物群落特征观测、土壤样品采集、土壤主要物理化学性质分析测定, 利用退化草地群落特征和土壤因子数据进行冗余分析, 对高寒草甸土壤因子与草地退化之间的关系进行探讨。 结果表明:不同退化程度草地沿冗余分析排序图第一排序轴分布, 第一排序轴反映草地退化程度的变化; 草地植物群落特征中与第一排序轴负相关且按相关程度大小排序的指标为植被覆盖度>地上生物量>多样性指数>均匀性指数; 第一、第二排序轴能够解释 90.3%的草地退化与土壤因子关系; 土壤温度、容重与第一排序轴正相关, 土壤含水量、全氮、有效氮、全磷、土壤有机碳与第一排序轴负相关, 有效钾、粘粒占比与第二排序轴负相关; 第一排序轴及所有排序轴所反映的土壤因子均与草地退化样地之间呈极显著相关关系(P<0.01); 不同土壤因子与草地退化之间关系密切程度不同, 土壤温度(r = 0.929)、容重(r = 0.915)、土壤含水量(r = –0.916)、全氮(r = –0.907)、有效氮(r = –0.859)、全磷(r = –0.809)、土壤有机碳(r =–0.662)等与高寒草甸退化相关程度更高且相关关系极显著(P<0.01); 土壤因子中筛选出土壤温度、 全氮等 9 个敏感性土壤指标, 能够解释 93.3%的草地退化与土壤因子关系。利用退化草地群落特征和土壤因子数据矩阵进行冗余分析能够综合反映土壤因子与草地退化之间的关系及相关程度, 筛选后的土壤因子能够作为高寒草甸草地退化的敏感性指示指标。     

藏北高原草地群落的数量分类与排序

采用TWINSPAN数量分类和DCA、CCA排序的方法,对藏北高原草地29个样点进行统计分析。结果显示:(1)TWINSPAN数量分类将藏北高寒草地群落划分成10种类型。(2)样点DCA排序第一轴基本反映了水分环境梯度,第二轴基本反映了热量梯度。(3)TWINSPAN分类所划分的各群落在DCA排序图上都有各自的分布范围和界限,说明DCA排序能较好的反应各优势群落与其环境资源之间的关系。(4)样点CCA排序表明,影响群落分布的首要环境因子是水分因子(年均降水量)和空间因子(经度),其次是热量因子(年均温度),CCA排序进一步阐明了群落分布决定于水分和温度等环境因子,并间接验证了TWINSPAN的分类结果。(5)物种CCA排序和TWINSPAN分类结果表明:植物群落中物种的分布格局与植物群落类型的分布格局存在一定的相似性。     

松山自然保护区森林群落的数量分类和排序

根据68个森林群落样方数据,采用双向指示种分析(TW INSPAN)方法,对松山自然保护区的森林群落进行分类和采用除趋势对应分析(DCA)、典范对应分析(CCA)方法进行排序。结果表明:(1)TW INSPAN将该区的森林群落分为13类型;(2)样方的DCA排序及样方和优势种的CCA排序较好地揭示了该区森林群落的分布格局与环境梯度的关系;CCA第一轴明显地反映出森林群落的海拔梯度、枯枝落叶层厚度和土壤深度变化,沿CCA第一轴从左到右,海拔逐渐升高,枯枝落叶层越厚和土壤越深;第二轴与海拔高度和坡度成正相关,而与土壤紧实度成负相关。其中海拔梯度是环境因子中对森林群落起决定性作用的因子。(3)与DCA相比,CCA的排序轴更有利于生态意义的解释,后者能同时反映样方间在种类组成上及环境因子组成上的相似性,表现在排序图中样方较集中,群落间的界线变得较模糊,因此如果排序同分类结合使用,DCA的效果要好于CCA。(4)TW INSPAN分类与DCA和CCA排序的结果,同时表明了该地区森林群落的垂直分布格局。     

中卫山羊核心产地植物群落的数量分类与排序

应用数量分类(TWINSPAN)和DCA排序方法,对我国特有裘皮用山羊(中卫山羊)核心产地——宁夏香山地区植物群落进行多元分析,根据TWINSPAN分类结果,并结合生态特征将所调查的28个样地植被分为6组,代表了该山地在海拔、地形、土壤、山坡坡度等环境作用下植被空间的分布格局。TWINSPAN分类结果与DCA排序结果较一致,DCA排序第一轴结果主要体现出海拔和山坡坡度对植被分布的作用,第二轴结果主要体现了地形(坡向)和土壤基质(沙地、石质山坡、土质山坡)对植被分布的作用。影响该干旱山地植被分布的主要环境因子有海拔和山坡的坡度,另外长期过度放牧对植被的空间分布影响较大,导致了该山地系统植被空间结构紊乱,并干扰了群落数量分析结果的准确性。     

卧龙自然保护区亚高山草甸的数量分类与排序

在野外植被调查的基础上,采用植被数量分析方法对岷江流域卧龙自然保护区亚高山草甸进行TWINSPAN分类和DCA排序,研究了植物种、植物群落与环境之间的关系.结果表明,该地区亚高山草甸共有植物139种,隶属于31科88属.应用数量分类方法将114个样方分为12个群落类型.在分析不同环境因子间的关系基础上,从定量的角度揭示了影响群落分布的主要因素是海拔梯度和土壤含水量.DCA排序图反映出排序轴的生态意义,第1轴反映了各群落类型所在环境的海拔梯度,从上到下,随着海拔的升高,植物群落或植物种的耐寒性越来越强;第2轴基本上反映了各群落类型所在环境的土壤含水量.排序结果与分类结果比较吻合,反映出植物群落类型和物种分布随环境因子梯度变化的趋势.     

黄河三角洲植被空间分布特征及其环境解释

为了解黄河三角洲地区植被空间分布与环境因子之间的关系,通过局地植被样方调查、区域遥感影像提取归一化植被指数(NDVI)及地形高度、地下水位埋深、表层土壤Cl~-含量等环境数据采集,综合样地植被与环境数据进行了除趋势对应分析(DCA)和除趋势典范对应分析(DCCA),并对区域NDVI与主要环境变量进行了单因子相关性分析和多元逐步回归分析。结果显示:DCA排序可将黄河三角洲植被分为翅碱蓬、柽柳-翅碱蓬、芦苇-柽柳、芦苇4个主要群落类型(群丛),DCCA与DCA排序图总体相似,但DCCA更清晰地表明其第一轴主要代表的是潜水Cl~-浓度等关键水盐因子,且随着水土环境系统盐分含量的减小,群落由翅碱蓬逐渐向芦苇演变。区域典型植被群落和NDVI分布格局与变化趋势受地下水位埋深和潜水Cl~-浓度2个环境因素影响较大(NDVI与2个环境变量间建立的二元回归方程R~2=0.57),而土壤Cl~-含量的植被效应实际上受地下水位埋深和潜水Cl~-浓度的影响。在区域地下水普遍浅埋条件下,地下水成为影响植被生长与分布的生态环境最敏感要素,而地下水位埋深和潜水Cl~-浓度是这一要素中的2个关键因子,尤其是后者梯度变化对天然植被分布格局起重要的控制作用。     

安西荒漠植物群落和优势种的分布与环境的关系

应用排序（ＤＣＡ）和回归分析方法对安西砾石戈壁荒漠植物群落及优势种的分布与环境的关系进行了研究。结果表明,该区群落的盖度（Ｃ）和密度（Ｄ）均与年降水量（Ｒ）有密切关系,而群落的种类丰富度（Ｎ）则与土壤含盐量（Ｓ）相关,其回归关系式为：Ｃ＝０．０５１９６８１６３ｅ０．０４０７８６８２１Ｒ（Ｒ＝０．９５,Ｐ＜０．０１）,Ｄ＝０．２７１４７９１３ｅ０．０５２７４１８２９Ｒ（Ｒ＝０．９６,Ｐ＜０．０１）,Ｎ＝１３．７７４８－６．４７７３０３ｌｇ１０００Ｓ（Ｒ＝０．８３,Ｐ＜０．０１）。即：年降水量是决定戈壁荒漠植物群落盖度和密度的主要因素,土壤含盐量则与群落种类丰富度的关系尤为突出。优势种的抗旱性顺序是：红砂（Ｒｅａｕｍｕｒｉａｓｏｎｇｏｒｉｃａ（（Ｐａｌ．）Ｍａｘｉｍ．）＞泡泡刺（ＮｉｔｒａｒｉａｓｐｈａｅｒｏｃａｒｐａＭａｘｉｍ．）＞黑柴（ＳｙｍｐｅｇｍａｒｅｇｅｌｉＢｇｅ．）＞珍珠（ＳａｌｓｏｌａｐａｓｅｒｉｎａＢｇｅ．）＞膜果麻黄（ＥｐｈｅｄｒａｐｒｚｅｗａｌｓｋｉＳｔａｐｆ．）,而耐盐性顺序是：珍珠＞红砂＞黑柴＞泡泡刺＞膜果麻黄     

Environmental Relations with Desert Plant Communities and Distribution of Dominants in Anxi

The ordination (DCA) and the regression analysis methods were used to study the relations between the Gobi desert plant communities as well as the distribution of the dominants and the environment in Anxi. The results indicated that the coverage(C) and density(D) of the plant communities have a close relation to the annual precipitation(R), but the species richness(N) of the plant communities has a relation to the salt content(S) in the soil. Their regression equations are as follows: C = 0. 051 968 163e0.040786821R (R = 0.95, P < 0.01), D = 0.27 147 913e0.052741829R (R =0.96,P Nitraria sphaerocarpa Maxim. > Sympegma regelli Bge. > Salsola passerina Bge. > Ephedra przewalskii Stapf., but the resistibility to salt of the main dominants was found in the order as follows: Salsola passerina > Reaumuria soongorica > Sympeg- rna regelli > Nitraria sphaerocarpa > Ephedra przewalskii.     

Vegetation changes along a precipitation gradient in Central Argentina

Changes in vegetation along a precipitation gradient in Central Argentina were studied. Floristic samples were taken along an east-west transect of about 300 km. Correlation analysis between precipitation and ordination axes was used to provide an environmental interpretation of vegetation variability.Floristic analysis produced an ordination of plant communities from evergreen forests (precipitation >500 mm) to desert shrublands and therophyte communities (precipitation <200 mm). Results showed a trend of floristic and structural impoverishment towards the west. There is a replacement of species along the transect and a shift in dominant growth forms. The first ordination axis is significantly, negatively correlated with annual precipitation.     

Quantitative classification and ordination of forest communities in Pangquangou National Nature Reserve

Quantitative analysis of ecological relationships between vegetation and the environment has become an essential means in the field of research of modern vegetation ecology. In this article, based on data from 84 quadrates, forest communities in this reserve were investigated using TWINSPAN, DCA and DCCA. The results will be helpful in the construction and development of Pangquangou National Nature Reserve. Using TWINSPAN, the forest communities were classified into seven types. The distribution pattern of vegetation reflects the comprehensive influence of environments. The results of DCA and DCCA clearly reflect the relationship between the pattern of forest communities and environmental gradients. The ordination result of DCCA indicates that altitude is more important than other environmental factors because the change of altitude gradient will lead to changes in the temperature and humidity gradients. The first of the DCA ordination axes indicates the humidity gradient, and the second indicates the temperature gradient. All these results show that the main factors restricting the distribution of communities in this reserve are temperature and humidity. The ecological meaning of the ordination axis in DCCA is much clearer than that in DCA, and the species-environment correlation of DCCA is more obvious than DCA. The first DCCA axis indicates the altitude gradient among the communities, while the second is the gradient in aspect and slope among the communities. DCCA ordination can simultaneously express similarities of species and environment. Therefore, the quadrat location in the DCCA ordination figure is much closer than in the DCA.     

Quantitative classification and ordination of forest communities in Pangquangou National Nature Reserve

Quantitative analysis of ecological relationships between vegetation and the environment has become an essential means in the field of research of modern vegetation ecology. In this article, based on data from 84 quadrates, forest communities in this reserve were investigated using TWINSPAN, DCA and DCCA. The results will be helpful in the construction and development of Pangquangou National Nature Reserve. Using TWINSPAN, the forest communities were classified into seven types. The distribution pattern of vegetation reflects the comprehensive influence of environments. The results of DCA and DCCA clearly reflect the relationship between the pattern of forest communities and environmental gradients. The ordination result of DCCA indicates that altitude is more important than other environmental factors because the change of altitude gradient will lead to changes in the temperature and humidity gradients. The first of the DCA ordination axes indicates the humidity gradient, and the second indicates the temperature gradient. All these results show that the main factors restricting the distribution of communities in this reserve are temperature and humidity. The ecological meaning of the ordination axis in DCCA is much clearer than that in DCA, and the species-environment correlation of DCCA is more obvious than DCA. The first DCCA axis indicates the altitude gradient among the communities, while the second is the gradient in aspect and slope among the communities. DCCA ordination can simultaneously express similarities of species and environment. Therefore, the quadrat location in the DCCA ordination figure is much closer than in the DCA.     

Primary Study on Interrelation Between Plant Communities and Environmental Factors in the North Shore of Qinghai Lake

Eighteen plant communities were surveyed by quaduats in the north shore of Qinghai Lake. The communities were analyzed using PCA (principal component analysis) ordination and regression procedure to determine the distribution patterns of the plant communities and relationship between the communities and environmental factors. The results showed that the distribution of the plant communities were closely related to the moisture and salt content of soil. The correlation between species diversity or ecological dominance of the communities and gradient of environmental factors was not significant, but the two indexes of community showed multivarient line relationship with the first principal component, or the gradient of soil water, and the regression model as below: Y =- 4.85 4–1.47X1 4- 10.71X2 (P<0. 01).     

大兴安岭沟谷冻土湿地植物群落分类、物种多样性和物种分布梯度

应用双向指示种分析法（TWINSPAN）和除趋势对应分析法（DCA）,对大兴安岭不同纬度的12个沟谷的冻土湿地植物群落之间的物种多样性和物种分布的环境梯度变化进行了分析．结果表明：研究区12个沟谷冻土湿地样地可划分为4个群丛组,分别位于不同的纬度范围;TWINSPAN的分类结果很好地反映了研究区沟谷冻土湿地植物群丛组的分布与纬度的关系,并在DCA二维排序图上得到了较好的验证．随着纬度的减小以及年均气温、年均降水量、1月平均气温和干燥度的增加,群落的物种多样性逐渐增大．研究区沟谷冻土湿地植物群落的灌木层和草本层的优势种和共优种多为适应湿地环境的沼生和湿生植物,随着纬度的减小,喜冷湿环境的沼生和湿生植物种类逐渐减少,甚至消失,而耐旱的中生植物的比重则逐渐加大.     

河西走廊盐化草甸主要植物群落分布特点及其土壤环境特征

 采用系统网格法调查河西走廊盐化草甸典型地段的植被和土壤环境因素,用DCA排序技术进行定量分析,来划分该区植物群落的分布格局,并以土壤环境指标(有机质、全盐含量、pH值、潜水位埋深)解释其所形成的5个样方组,反映出内陆干旱次生盐渍化区土壤水盐分布的差别同潜水位的关系。     

小陇山国家级自然保护区次生林分类、排序及演替

在野外调查基础上,采用TWINSPAN和DCA对小陇山林区次生林群落进行了数量分类和排序,从植物群系组成、植物群落与环境的生态关系方面,研究小陇山植被群落的分布格局,用以确定该区次生林演替,并给予合理的环境解释。结果表明:采用TWINSPAN数量分类方法,将植被划分为12个群落类型;DCA排序图明显反映出排序轴的生态意义,第一轴基本上突出反映了湿度变化,沿第一轴从左到右,湿度逐渐增大;第二轴主要表现了温度梯度,沿第二轴从下到上,温度逐渐降低;次生林的演替序列为山杨林→山杨+白桦林→锐齿栎混交林及锐齿栎纯林,其自然恢复演替以锐齿栎林为顶极群落。