协惯量分析与典范对应分析在植物群落排序中的应用比较

采用协惯量分析(PCA-CA COIA)和典范对应分析(CCA)两种排序方法, 对北京小龙门林场的黄檗 (Phellodendron amurense)群落进行了分析, 并用Spearman秩相关系数检验了对应排序轴的相关性。两种排序方法得出的结果基本一致, 两者的第一排序轴都反映了海拔高度和坡向对群落分布的影响, 而各自第二、第三排序轴所代表的环境意义有所差异, 并出现了交叉, 但是两者的前3个排序轴均反映了海拔、坡位、土壤厚度和凋落物层厚度的变化趋势, 说明在环境因子个数较少或共线性效应不明显的情况下, 协惯量分析也能达到CCA的分析效果, 并且在排序轴特征值解释量上高于典范对应分析。     

Nuovi micromiceti su Pandanacee

Abstract

Helianthemetea guttati communities are pioneer spring and early summer ephemeral grasslands, dominated by non-nitrophilous therophytes. In Continental Portugal, these communities have not yet been fully investigated, and thus the objectives of the present study are: (1) to identify community types in therophytic grasslands; (2) to recognize those communities that configure the European priority habitat 6220* (pseudo-steppe with grasses and annuals); (3) to establish environmental gradients underlying their spatial variation; (4) to assess how floristic composition is affected by land use factors. Vegetation sampling using phytosociological methodology was carried out on 80 grasslands. Modified Twinspan classification and canonical correspondence analysis (CCA) was applied for the classification and ordination of relevés whereas partial CCA (pCCA) and variation partitioning were used to assess the relative influence of individual land use factors. Some 270 species were identified across 11 community types whose floristic patterns were mainly explained by environmental gradients related to altitude and soil type while land use variables could only explain a small part of the floristic variation. Based on biogeography and the determination of diagnostic species, four phytosociological new associations and a new subassociation are proposed: Holco-Brachypodietum distachyi, Holco-Micropyretum tenellae, Micropyro-Anthoxanthetum aristati and Leontodonto-Vulpietum bromoidis vulpietosum membranaceae.     

Comparison of different treatments of rare species in canonical correspondence analysis

运用吕梁山南段植物群落及其环境调查数据,比较研究不同稀有种处理(剔除稀有种、稀有种不做处理与降低稀有种权重3种方法处理)对典范对应分析(CCA)排序结果的影响,并用Spearman秩相关系数检验对应排序轴的相关性。结果表明3种方法的分析效果基本一致,但它们对环境因子的解释趋势有差异。基于环境数据、物种数据和样方数据的排序轴相关分析结果显示:未处理稀有种的CCA与降低稀有种权重的CCA吻合度高于剔除稀有种的CCA与降低稀有种权重的CCA的吻合度,未处理稀有种的CCA与降低稀有种权重的CCA的前4轴呈极显著的一一对应关系;剔除稀有种的CCA和降低稀有种权重的CCA仅在基于环境数据和样方数据分析时前3轴呈极显著的一一对应关系,而在基于物种数据的相关分析时前4轴的对应相关性不显著。从物种-环境关系的解释量上来看,降低稀有种权重的CCA最优,剔除稀有种的CCA和未处理稀有种的CCA次之。结合对应排序轴的相关性分析和物种-环境关系累计解释量来看,这3种稀有种处理方法在准确地揭示物种与环境关系时的顺序依次为:降低稀有种权重>对稀有种不做处理>剔除稀有种。     

山西灵空山小蛇沟林下草本层植物群落梯度分析及环境解释

通过对山西灵空山小蛇沟集水区的林下草本层植物群落进行调查和多元分析——TWINSPAN分类、典范对应分析(CCA)与生境、生物因素变量分离, 探讨林分水平上草本层物种分布与环境因子之间的关系。结果如下: 1) TWINSPAN将26个调查样方划分为6种群落类型: 以辽东栎(Quercus wutaishanica)为主的辽东栎-油松(Pinus tabulaeformis)林型、辽东栎杂木林型、辽东栎林型、华北落叶松(Larix principis-rupprechtii)林型、油松林和阔叶油松林型、油松-辽东栎均匀混交林型, 体现了该地区地带性植被类型为暖温带森林的特点。2)群落类型的划分与CCA的结果相吻合, 主要反映了CCA排序第一、二轴的环境梯度, CCA排序轴第一轴突出反映了林分类型与土壤养分梯度, 第二排序轴与坡度、坡位显著相关。Monte Carlo检验结果表明, 林分类型、土壤养分和坡度是影响小蛇沟集水区内林下草本物种分异的最主要的环境因子。3)生境因子与生物因子解释了物种格局变化的42.9%, 其中生境因子占31.8%, 生物因子占7.9%, 生境因子与生物因子交互作用解释部分占3.2%。良好的环境解释反映了调查取样和环境因子选取的合理性。对于50%以上未能被解释的变异部分, 可能归咎于未被选取的因子如干扰或者随机过程。4)在海拔梯度较小的山区, 坡向等小地形因子能较好地指示局部生境的小气候条件, 对林下植物的分布有较好的解释力。     

干扰、地形和土壤对温州入侵植物分布的影响

分析自然因子和人为活动对入侵植物分布的影响,有助于预测外来植物的入侵.本研究采用路线踏查和样地调查相结合的方法,对温州地区外来入侵植物的组成和分布进行3次调查,同时记录样地土壤类型、地形、人为干扰等环境因子.使用典范对应分析(canonical correspondence analysis)进行排序,分析外来植物的分...     

Distribution, ecological tolerance and optimum levels of freshwater Ostracoda (Crustacea) from Diyarbak?r, Turkey

A total of 23 ostracod taxa were found in 48 of 90 different water bodies (wetlands, springs, lakes, creeks, etc.) located at moderate to high elevation (530–1,095 m) in Diyarbakır province. The ecological tolerances and optimum values for environmental variables of 15 species were analyzed. Accordingly, maximum numbers of species were found between 700 and 800 m. Ostracod species and sampling sites along with seven environmental variables were ordinated with canonical correspondence analysis (CCA). The first axis of CCA explained 72% of the relationship between species and environmental variables. Of these, water temperature, redox potential and altitude were the most influential (P < 0.05) factors for species. Based on habitat similarities, an unweighted pair group mean average dendrogram divided species into four clustering groups. Among the species, Potamocypris arcuata, Candona neglecta and Psychrodromus fontinalis had the highest optimum estimates for altitude, whereas P. arcuata, Herpetocypris brevicaudata and P. fontinalis exhibited the highest tolerances to altitude. While most species revealed unique tolerances and optimum values for different ecological variables, species with cosmopolitan characteristics had wider ranges of ecological tolerances and distribution amid the variety of habitats along elevational gradients.     

桂江流域附生硅藻群落特征及影响因素

研究了桂江流域水质、土地利用、地理因素对河流附生硅藻群落的影响。结果显示,桂江流域电导率(Conductivity,Cond.)由下游至源头呈降低趋势,其它水质参数变化趋势不明显。主成分分析(Principle Component Analysis,PCA)显示前两个主成分共解释了56.2%的水质特征,第一轴反映了氨氮(NH4-N)、硝氮(NO3-N)、总氮(Total Nitrogen,TN)的变化梯度,第二轴反映了水温(WT)、pH、Cond.、溶解氧(Dissolve Oxygen,DO)的变化梯度。桂江流域硅藻特定污染敏感指数(Specific PolluoSensitivity Index,IPS)和硅藻生物指数(Biological Diatom Index,IBD)下游低于源头,差异不显著,与多项水质、土地利用以及地理因子呈线性显著相关。24个样地共发现112种硅藻,丰富度大于5%的37种,丰富度最大的几个种类依次为Achnanthidium minutissimum,A.pusilla,A.tropica,Cymbella laevis。对应分析(Corresponding Analysis,CA)显示桂江流域存在3个差异较大的硅藻群落,流域下游以Nitzschia recta为优势种,A.lanceolata、Amphora montan、Planothidium frequentissimum在中下游丰度较高,上游区域种类较多。典型相关分析(Canonical Correspondence Analysis,CCA)排序前两轴解释了硅藻群落变异程度的28.60%,CCA排序轴1与水质(Cond.、WT、NH4-N、NO3-N、TN)和土地利用(城市面积、农田面积、植被覆盖)显著负相关,与地理因素(流域面积、海拔、坡度)显著正相关,第二轴与浊度(NTU)显著正相关(P<0.05)。偏典型相关分析(Partial CCAAnalyses)显示,土地利用、地理因子、水质分别解释了桂江流域硅藻群落变异的7.20%,17.50%,48.50%。结果表明,桂江流域附生硅藻群落结构是水质、地理因子和土地利用共同作用的结果,水质起决定性作用,电导和不同形态的氮是影响附生硅藻群落结构的主要水质因素。     

东灵山濒危植物刺五加生存群落的数量分析

在样方调查的基础上,分别采用双向指示种分类法(TWINSPAN)、除趋势对应分析法(DCA)和典范对应分析(CCA)对东灵山地区濒危植物刺五加的生存群落进行数量分析。TWINSPAN分类将刺五加生存群落分为9类,分类结果在DCA二维排序图上得到了较好的验证,其中第一轴反映的是海拔梯度,第二轴反映了坡向、坡度的变化。刺五加多分布在位于海拔较高、光照较少的杂木林中,除在少数群落中成为灌木层的优势种外,相对分布较少。CCA排序结果与DCA的排序结果基本一致,反映出植物群落分布随环境因子梯度变化的趋势,揭示了海拔和光照是限制刺五加生长的主要环境因子。     

重庆主城区地面苔藓植物群落特征及其与环境的关系

通过对重庆主城区44个样地的地面苔藓植物进行样方调查,应用物种多样性指数和典范对应分析(CCA),研究了该地区苔藓植物种类组成、物种多样性和群落与环境因子的关系.结果表明： 石生群落共有苔藓植物25科43属86种;土生群落共有苔藓植物22科28属46种.相比公园、风景区和缙云山国家级自然保护区,大学校园的石生和土生苔藓植物物种多样性水平较高.双向指示种分析结果将石生群落划分为3种类型,土生群落划分为2种类型.典范对应分析显示,林冠郁闭度是影响公园和大学校园内石生苔藓植物的主要环境因子;海拔、相对湿度和人为干扰程度是影响自然保护区和旅游景区内石生苔藓植物的主要环境因子.土壤〖JP2〗pH值、人为干扰程度和林冠郁闭度是影响公园和大学校园土生苔藓植物的主要环境因子;海拔、相对湿度和土壤含水量是影响自然保护区和旅游景区内土生苔藓植物的主要因子.     

Quantitative analysis of endangered Acanthopanax senticosus communities in Dongling Mountain of Beijing

Based on the survey of community plots, a quantitative analysis of endangered Acanthopanax senti-cosus communities in Dongling Mountain was performed with two way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA). The communities of A. senticosus were classified into 9 types by TWINSPAN and the results were validated by DCA. On the DCA graph, the first axis reflected the gradient of altitude and the second axis reflected the aspect and slope. Most of A. senticosus were distributed in the thick forests at a high altitude with little light. With the exception of being a dominant species of shrub layers in a few communities, A. senticosus has a relatively scarce distribution. In accordance with DCA, the results of CCA also show the trend that the distribution of A. senticosus communities varied along with the gradient change of environmental factors. Altitude and light are the main factors affecting A. senticosus growth.     

Patterns in the distribution of freshwater fishes in rivers of Central Western Ghats, India and their associations with environmental gradients

The community ecology of freshwater fishes in four river systems (Sharavati, Aghanashini, Bedti and Kali) of the central Western Ghats (India) has been studied for the first time. Patterns of fish species distributions were analysed and important stream and environmental parameters determining the species richness and composition of this region were identified. Upstream--downstream trends in species richness and diversity as well as changes in stream characteristics were studied using univariate correlation analyses. Preliminary analyses on changes in species composition and feeding guilds showed the presence of a gradual species turnover along the stream gradient. There were associated changes in the major feeding guild compositions, with a higher proportion of insectivore and algivore/herbivore composition in the upper reaches shifting to a predominance of omnivores and carnivores downstream. Pearsons product--moment correlation analyses along with stepwise multiple regression analyses identified stream depth and altitude as the important parameters determining species richness. Canonical correspondence analysis was performed to study species associations with environmental parameters. The analysis showed a strong species environmental correlation to the CCA axes, a high significance for the CCA axis 1 as well as for the overall test. The plots of the species and site scores on the CCA axes showed a clear segregation of species based on their relations with environmental and stream properties. This study is an important step in our understanding of the community structure of fish species of these rivers and would be helpful in future efforts on the conservation of aquatic communities and their habitats.     

地形对桂西南喀斯特山地森林地表植物多样性及分布格局的影响

利用协方差分析、曲线回归拟合及典范对应分析(CCA),研究了地形因子对桂西南喀斯特森林地表植物多样性及不同生长型地表植物分布格局的影响.结果表明： 共调查到152种地表植物,其中,蕨类植物37种、草本44种、藤本9种、灌木62种;协方差分析显示,海拔与地表植物个体数和丰富度显著相关,坡向对地表植物丰富度具有显著影响;地表植物的个体数和丰富度与海拔梯度存在显著的非线性相关性;CCA分析显示,坡向对蕨类植物的分布格局影响显著,坡度对草本、藤本和灌木的分布格局影响显著.蕨类植物对坡向引起的水热条件改变响应更为敏感,坡度对土壤水分、养分的作用大于高程,是影响本区域草本、藤本和灌木3种地表植物分布的主要地形因子.     

长白山地区曲尾藓属植物生态分化的排序研究

曲尾藓属(ＤｉｃｒａｎｕｍＨｅｄｗ.)属于顶蒴藓类植物,在长白山地区主要分布于苔原、森林林下和沼泽地中[1,2]。分析曲尾藓属植物对不同生态环境的适应特点和种间生态关系,对揭示该属植物物种分化的生态学机制,有一定学术价值。排序是分析植物群落分布与环境关系的常用方法,以往人们主要是应用ＤＣＡ、ＰＣＡ等方法,因而不同种类与环境关系的解释带有较大的主观性。典范对应分析能够在同一排序图上展示植物种类与环境因子的关系,是当前最有效的排序方法,其结果的生态学解释比较客观。Ｓｌａｃｋ指出应用排序也能够研究植物种间的生态位分…     

钱塘江中游流域不同空间尺度环境因子对底栖动物群落的影响

溪流底栖动物群落结构受不同空间尺度环境因子的共同作用。基于2010年钱塘江中游流域60个样点的大型底栖无脊椎动物和环境变量数据,寻找与研究流域底栖动物群落结构变化密切相关的关键环境变量,解析流域尺度和河段尺度的环境因子对底栖动物群落的相对影响。PCA分析表明该区域的主要环境梯度是流域内的土地利用类型及其引起的溪流物理生境退化程度和水体营养状态。CCA分析发现影响底栖动物群落的流域尺度的关键环境变量是纬度、海拔、样点所在流域大小、森林用地百分比,河段尺度是总氮、总磷、钙浓度、二氧化硅浓度和平均底质得分。偏CCA分析得到两种尺度环境因子对底栖动物变异的总解释量为26.4%,流域尺度和河段尺度变量分别为总解释量的50%和31%;方差分解结果表明研究区域大型底栖无脊椎动物受到两种尺度环境因子的综合影响,且流域尺度环境因子较河段尺度环境因子更为重要,体现了其在溪流生态系统保护、恢复、监测和评价中的重要参考价值。     

Coastal plant and soil relationships along the southwestern coast of South Korea

We studied how plant species distribution was regulated by the relationships between vegetation and soil factors on the southwestern coast of South Korea. Vegetation was classified using two-way indicator species analysis (TWINSPAN), thereby producing four vegetation groups that were linked to three habitat types. Two ordination techniques —; detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) —; were applied to examine the relationships between vegetation and 12 edaphic factors, including soil pH, water and osmotic potentials, moisture content, electrical conductivity, Cl and Na⁺ contents, total Kjeldahl nitrogen, and contents of organic matter, sand, silt, and clay. Results were similar for both types of evaluations. According to DCA and CCA, the 23 communities tended to cluster into three types: salt swamp, salt marsh, and sand dune. The first two canonical axes accounted for 14.9% of the community-soil factor relationship among communities. As identified via CCA, the main gradients were soil-water relations and soil texture.     

应用典范对应分析探讨长白山金发藓科植物的生态位分化

应用典范对应分析(Canonical Co rrespondence Analysis, CCA)对长白山主要生态系统30个样点中的13种金发藓科植物分布与环境因子间的关系进行了研究。发现在长白山地区,金发藓科植物在海拔高度、土壤含砂量、含水量、酸度、光照条件等资源维上存在明显的生态分化现象。13种金发藓科植物中,球蒴金发藓(Polytrichum sphaerothecium(Besch.)C.Mull.、高山异发藓短叶变种(Polytrichastrum alpinum var. brevifolium(R.Br.)Brid.)在海拔上,拟异发藓(Polytrichastrum formosum(Hedw.)G.L.Smith)、变形异发藓(Polytrichastrum dicipensLimpr.)、毛尖金发藓(Polytrichum piliferum Schred.ex Hedw.)、桧叶金发藓(Polytrichum juniperinum Willd.ex Hedw.)在光照上以及大金发藓(Polytrichum commune Hedw.)、直叶金发藓(Polytrichum juniperinum ssp. strictum(Brid.)Nhy.&Sael.)在土壤酸度与水分上的生态要求比较接近。     

紫金山国家森林公园苔藓植物多样性及其与环境关系研究

为深入了解紫金山国家森林公园苔藓植物资源,对南京紫金山展开苔藓植物野外调查,应用典范对应分析(CCA)研究苔藓植物分布与环境间关系。结果表明,调查中共记录苔藓植物23科37属65种,青藓科(Brachytheciaceae)、丛藓科(Pottiaceae)、羽藓科(Thuidiaceae)和绢藓科(Entodontaceae)为优势科(≥6种),绢藓属(Entodon)、青藓属(Brachythecium)、匐灯藓属(Plagiomnium)和真藓属(Bryum)为优势属(≥4种);苔藓植物生境以土生为主,树生较少;苔藓植物生活型以交织型和丛集型为主,占比分别达46.15%和35.38%;苔藓植物区系以温带和东亚成分为主,区系成分呈现明显过渡性;CCA排序结果表明,湿度、坡向和海拔是影响该区域苔藓植物分布的主要环境因子。     

Environmental parameters determining water mite assemblages in Costa Rica

This paper presents an ecological analysis of the water mite fauna of 350 streams, rivers, springs and standing waters from all main regions, ecosystems and elevations in Costa Rica. From 509 sample sites about 20,000 water mites representing 74 genera in 21 families were collected. 17 habitat types were distinguished and 11 further environmental parameters were measured. The significance of the particular parameters was analysed using canonical correspondence analysis (CCA). Habitat type, elevation, temperature and velocity were identified as major factors determining water mite assemblages. The analyses showed the existence of characteristic water mite coenoses in different neotropical habitats and the suitability of neotropical water mites for biomonitoring programmes.     

Environmental parameters determining water mite assemblages in Costa Rica

This paper presents an ecological analysis of the water mite fauna of 350 streams, rivers, springs and standing waters from all main regions, ecosystems and elevations in Costa Rica. From 509 sample sites about 20,000 water mites representing 74 genera in 21 families were collected. 17 habitat types were distinguished and 11 further environmental parameters were measured. The significance of the particular parameters was analysed using canonical correspondence analysis (CCA). Habitat type, elevation, temperature and velocity were identified as major factors determining water mite assemblages. The analyses showed the existence of characteristic water mite coenoses in different neotropical habitats and the suitability of neotropical water mites for bio-monitoring programmes.     

Environmental factors and vegetation composition, Lefka Ori massif, Crete, S. Aegean

Aim The aim of this study was to explore the environmental factors that determine the spatial distribution of oro‐mediterranean and alti‐mediterranean plant communities in Crete. Location The paper provides a quantitative analysis of vegetation–environment relationships for two study areas within the Lefka Ori massif Crete, a proposed Natura 2000 site. Methods Eleven environmental variables were recorded: altitude, slope, aspect, percentage of bare rock, percentage of unvegetated ground, soil depth, pH, organic matter content and percentages of sand, silt and clay content. Classification of the vegetation was based on twinspan , while detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to identify environmental gradients linked to community distribution. Results One hundred and twenty‐five species were recorded from 120 plots located within the two study areas. Forty‐seven of the recorded species are endemic, belonging to 35 families. Hemicryptophytes and chamaephytes were the most frequent, suggesting a typical oro‐mediterranean life form spectrum. The samples were classified into five main community types and one transitional. The main gradients, identified by CCA, were altitude and surface cover type in the North‐west site, while in the Central site the gradients were soil formation‐development and surface cover type. Main conclusions The use of classification in combination with ordination techniques resulted in a good discrimination between plant communities and a greater understanding of controlling environmental factors. The methodology adopted can be employed for improving baseline information on plant community ecology and distribution in Mediterranean mountain zones.