河北小五台山国家级自然保护区森林群落与环境的关系

植物与环境之间的关系是一个复杂的演变过程,运用数量生态学方法探讨森林群落的物种组成、种群的生态特征、不同植物群落与环境之间的关系,有助于保护该区森林群落的稳定性和生物多样性。根据148个森林群落样方数据,选用双向指示种分析(TWINSPAN)和典范对应分析(CCA)方法,对河北小五台山国家级自然保护区森林群落进行分类和排序研究。结果表明:(1)TWINSPAN将该区的森林群落分为20个类型;(2)CCA排序结果较好地反映出群落分布格局与环境梯度的关系,各个森林群落类型在前两轴分异明显,在11个环境因子中,海拔、坡位、凋落层厚度、土壤导电率、土壤温度、土壤湿度、土壤厚度和干扰程度这8个环境因子对森林群落的分布起较大的作用,影响森林群落的分布格局,形成不同的植被类型。(3)乔木层优势种的CCA二维排序图所揭示的环境梯度与群落类型的分布有很大的相似性;t值双序图阐明了海拔、凋落层厚度、土壤温度、干扰程度等环境因子对森林群落乔木层优势种有着重要影响。采用TWINSPAN分类与CCA排序的方法,较好地解释了森林群落与环境因子的关系,为小五台山地区森林生态系统的科学管理和保护提供了理论依据,研究结果也为同类地区森林生态系统研究及保护提供参考和借鉴。     

桂林岩溶石山青冈群落数量分类与排序

植物群落的数量分类和排序可以客观地揭示植物群落与环境之间的关系,从而能为植被恢复与重建、森林经营与管理和生物多样性保护等提供理论依据。基于群落学调查和环境因子测定数据,采用Ward聚类、双向指示种分析(TWINSPAN)和多元回归树(MRT)对桂林岩溶石山青冈群落进行数量分类,选用冗余分析(RDA)进行排序,分析其与环境因子之间的关系。结果表明:(1)3种分类方法所得结果基本一致,可将桂林岩溶石山青冈群落划分为3个群丛类型,分别为青冈-粗糠柴+龙须藤+红背山麻杆-三穗薹草群丛(Ass.Cyclobalanopsis glauca-Mallotus philippensis+Bauhinia championi+Alchornea trewioides-Carex tristachya)、青冈-龙须藤+红背山麻杆+干花豆-宽叶沿阶草+三穗薹草群丛(Ass.Cyclobalanopsis glauca-Bauhinia championi+Alchornea trewioides+Fordia cauliflora-Ophiopogon platyphyllus+Carex tristachya)、青冈-粗糠柴+干花豆-三穗薹草群丛(Ass.Cyclobalanopsis glauca-Mallotus philippensis+Fordia cauliflora-Carex tristachya);(2)冗余分析结果较好地反映出各群丛类型的分布格局及其与环境梯度的相互关系,在10个环境因子中,岩石裸露率、土壤含水量、pH值、全氮、全磷、全钾、速效钾这7个环境因子对群落的分布影响显著。土壤含水量和全钾含量可能是影响该植物群落物种组成与分布的重要生态因子。     

新疆博格达山地面生苔藓植被的数量分类与排序研究

 应用数量分类(TWINSPAN)和排序(DCA)方法,对新疆博格达山苔藓植被进行了多元分析。TWINSPAN结果表明,该地区苔藓植被可分为6个主要群落类型,即牛角藓-真藓(Cratoneuron-Bryum)群落、扭口藓-墙藓(Barbula-Tortula)群落、提灯藓-细罗藓(Mnium-Leskeella)群落、对叶藓-提灯藓(Distichium_Mnium)群落、墙藓-连轴藓(Tortula_Schistidium)群落、扭口藓-紫萼藓(Barbula_Grimmia)群落,它们分别分布于山地荒     

秦岭山地天然次生林群落MRT数量分类、CCA排序及多样性垂直格局

采用多元回归树(MRT)对秦岭山地天然次生林群落进行数量分类,采用典范对应分析(CCA)进行排序,分析了秦岭山地天然次生林群落物种多样性沿海拔梯度的变化规律。结果表明:(1) 275个样方共有种子植物195种,隶属61科128属。乔、灌、草3个层次物种多样性变化沿海拔梯度的变化趋势基本一致,呈单峰模型;(2)经交叉验证认为秦岭山地天然次生林群落可分为2类,Ⅰ冬瓜杨(Populus purdomii)+陇东海棠(Malus kansuensis)+蛇莓(Duchesnea indica)群落,Ⅱ锐齿槲栎(Quercus aliena var. acuteserrata)+黄栌(Cotinus coggygria)+茜草(Rubia cordifolia)群落;(3) CCA排序结果揭示了群落生境的分布范围,反映出生态轴的排序意义,较好地反映秦岭山地天然次生林群落与环境因子的关系,其结果表明,海拔、坡向、凋落层厚度和干扰情况4个变量对该地区次生林群落的分布有较大的影响。     

Overstory vegetation and successional trends of Land Between The Lakes,USA

133 stands from the uplands of Land Between The Lakes (LBL) were sampled. Stand data were ordinated to identify clinal patterns in the overstory vegetation. A coeno-cline, accounting for 52% of the species variance, was developed from the first ordination axis. Classification of stands identified nine dominance types: Pinus echinata-Quercus spp., Q. prinus, Q. prinus-Q. alba, Q. stellata-Q. alba, Q. velutina-Q. alba, Q. alba, Q. alba-Q. rubra, Acer saccharum-Q. alba-Fagus grandifolia sadF. grandifolia-A. saccharum. Compositionally-stable (climax) and unstable (successional) stands were analyzed separately. Trajectories of unstable stands include the succession of P. echinata to Quercus-dominated communities on xeric sites and of Quercus types to more mesophytic communities (e.g. A. saccharum and F. grandifolia) onmesic sites. These shifts indicate the nature of the future climax overstory composition at LBL. The first axis DCCA ordination for climax stands accounted for 45% of the vegetation variance. Factor Analysis identified two significant suites of variables related to vegetation: soil chemistry/soil moisture and soil texture. Specific variables related to variation in the climax vegetation include soil pH, calcium and magnesium, effective soil depth, available water capacity, percent rock in the soil, slope position, aspect, elevation and distance to the opposing slope. Modal positions of species along the direct gradient ordination were similar in rank order to those derived from the indirect gradient ordination of all stands. The latter ordination represents the present forest vegetation pattern at LBL. Climax stands showed a shift in modes of Quercus spp. toward the xeric end of the gradient and increases in habitat width of mesophytic species. Following a reduction in disturbance, species appear to adjust to changes in competition and available habitat. That is, the dimensions of realized niches (i.e. habitat widths) change with succession. The climax vegetation at LBL appears to show centrifugal organization.     

新疆天山森林公园土壤螨类群落多样性与环境因子的相关性

为探讨西北干旱区森林土壤螨类群落和环境因子的相互关系,于2014年对新疆天山森林公园七种不同生境进行土壤螨类群落调查与环境因子测定,并采用除趋势对应分析法(DCA)和冗余分析法(RDA)对土壤螨类群落结构和多样性特征及其与环境因子之间的关系进行相关分析。结果表明,共捕获土壤螨类成体标本24399只,隶属4目56科108属(包括9个中国新记录属),其中小甲螨属Oribatella为优势类群。方差分析表明,在7种不同生境之间土壤螨类群落多样性指标均存在显著差异(P<0.05),Shannon-Wiener多样性指数(H)依次为针叶林>苗圃林>阔叶林>灌木林>针阔混交林>草甸草原>林中草地。RDA分析结果表明,第一主轴和第二主轴分别解释了土壤螨类主要群落总变量的34.8%和27.3%,所有环境因子共解释了土壤螨类群落物种组成变异的82.1%。蒙特卡罗置换检验显示,十种环境因子与全部排序轴(F=7.355,P=0.002)均存在极显著的相关性。研究表明,海拔、土壤含水量和有机质含量对螨类群落结构和多样性的影响显著。     

三江平原农田地表和地下土壤螨类丰富度与环境因子的空间关联性

地表和地下土壤动物群落空间格局及其与环境因子的空间作用关系,是揭示地表-地下生态系统格局与过程及生物多样性维持机制的重要基础。于2011年在三江平原农田生态系统,在50m×50m的空间尺度内,基于地统计空间分析方法,揭示地表和地下土壤螨群落及不同螨类物种丰富度的空间格局,并分析这种空间格局与土壤含水量、土壤p H值及大豆株高空间格局的空间关联性。半方差函数和普通克里格插值表明,8月份地表、地下和10月份地下螨群落及这些群落内大部分螨类物种在特定空间尺度内形成集群,表现为空间异质性特征,且这种空间分异多由结构性因素或结构性因素和随机性因素共同调控。交叉方差函数表明,土壤螨群落和不同螨类物种的空间格局与环境因子的空间格局在多种尺度上表现出复杂的空间关联性(正的或负的)。但简单Mantel检验仅发现8月份地表中气门亚目未定种1(Mesostigmata unidentified sp.1)和大豆株高存在明显的正的空间关联性。研究结果表明地下螨群落和生长季节的地表螨群落具有明显的空间异质性结构,地表和地下螨群落及大多数螨类物种丰富度与土壤含水量、土壤p H值及大豆株高的空间关联性并不显著。促进地表-地下生态系统土壤动物群落空间格局研究,为地表-地下格局与过程研究奠定基础。     

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。     

Spatial and environmental determinants of plant species diversity in a temperate desert

Aims Deserts are one of the ecosystems most sensitive to global climate change. However, there are few studies examining how changing abiotic and biotic factors under climate change will affect plant species diversity in the temperate deserts of Asia. This study aimed to: (i) characterize species distributions and diversity patterns in an Asian temperate desert; and (ii) to quantify the effects of spatial and environment variables on plant species diversity.Methods We surveyed 61 sites to examine the relationship between plant species diversity and several spatial/environmental variables in the Gurbantunggut Desert. Spatial and environmental variables were used to predict plant species diversity in separate multiple regression and ordination models. Variation in species responses to spatial and environmental conditions was partitioned by combining these variables in a redundancy analysis (RDA) and by creating multivariate regression trees (MRT).Important findings We found 92 plant species across the 61 sites. Elevation and geographic location were the dominant environmental factors underlying variation in site species richness. A RDA indicated that 93% of the variance in the species–environment relationships was explained by altitude, latitude, longitude, precipitation and slope position. Precipitation and topographic heterogeneity, through their effects on water availability, were more important than soil chemistry in determining the distribution of species. MRT analyses categorized communities into four groups based on latitude, soil pH and elevation, explaining 42.3% of the standardized species variance. Soil pH strongly influenced community composition within homogeneous geographic areas. Our findings suggest that precipitation and topographic heterogeneity, rather than edaphic heterogeneity, are more closely correlated to the number of species and their distributions in the temperate desert.     

Spatial variation in insect community and species responses to habitat loss and plant community composition

Several experimental studies have examined species responses to manipulations of habitat area and spatial arrangement, but plant composition and spatial variation in species distributions also affect animal responses to habitat alteration. We used an experimental approach to study the combined effects of habitat area, edge, and plant community composition on the spatial structure of insect species richness and composition. The abundance of three guilds (herbivores, predators and parasitoids) and individual species were also analyzed. Habitat patches were created that differed in area and edge by selectively mowing portions of 15 m×15 m plots in a 1.7-ha old field. Spatial and environmental variables were used to predict insect responses in separate multiple regression and ordination models. The variation in species responses due to spatial and environmental variables was then partitioned by combining these variables into an overall regression or ordination. Spatial and environmental variables contributed similar percentages to the total variance in insect species richness, abundance or composition. No significant effects of habitat area were observed in any response variable. Herbivore abundance showed positive responses to legume or grass cover, as well as spatial variation that was unrelated to environmental variables. Predators and parasitoids had greater effects of plant species richness and habitat edge, and less unexplained spatial variation. Individual species differed in their responses to plant variables, depending on host specialization or intraspecific aggregation. Our study highlights the importance of plant community composition and spatial variation apart from environmental variables. Spatial variation stems both from species responses to environmental features as well as species differences in habitat specialization and intraspecific aggregation.     

The ecology of Araucaria species in New Guinea. I. Ordination studies of forest types and environments

Previous studies of the ecology and regeneration strategies of Araucaria cunninghamii and A. hunsteinii in New Guinea rainforests have treated these species as ecologically identical and disagree concerning their ability to maintain a stable population size in forest communities dominated by angiosperms. Vegetation data from a number of 0.5 ha forest sites in New Guinea are analysed in order to characterize forest types and their environmental regimes in the altitudinal zone from 700 to 1500 m a.s.l. Particular attention is paid to forests containing Araucaria species. Nodal component analysis identifies a number of distinct forest types or ‘series’, each dominated by a different species. Continuity analysis displays the location of sites and species in non-linear ordination space. Subsequent regression of environmental data on the position of sites in ordination space shows that forest types are separated along gradients related to altitude and rainfall on the one hand, and soil nutrient concentrations on the other. A. cunninghamii is generally found in wetter and less nutrient-rich sites than A. hunsteinii. The analysis of species presence data, as opposed to quantitative data, shows that whilst forest types are easily differentiated according to their dominant species, changes in floristic composition are subtle along the altitudinal and other gradients recognized.     

Cultivated and fallow fields harbor distinct communities of Basidiomycota

Basidiomycota constitute a group of fungi with highly diverse ecological strategies from ectomycorrhizas and plant pathogens to saprotrophic fungi. We used 454 sequencing to obtain sequences of Basidiomycota from a cultivated and an adjacent fallow field, to investigate the influence of soil cultivation on the species composition and distribution patterns. Nonparametric multidimensional scaling (NMS) clearly segregated the basidiomycetes communities in the two fields, though some species were shared. Axis 1 and 2 of the ordination correlated with soil organic matter content and pH respectively. Most OTUs had affinity to known species, but some unknown clades were seen in both fields. Spatial analysis demonstrated higher spatial autocorrelation (up to 50 m) in the managed field in comparison with the fallow field. The study showed that agricultural soils have considerable species richness, and that community composition and turn-over potentially is influenced both by land use and spatial scale.     

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.     

Litter Biomass and Nutrient Determinants of Ant Density, Nest Size, and Growth in a Costa Rican Tropical Wet Forest

The nutritional demands of animals vary by taxon. Across landscapes, communities of animals experience variability in the stoichiometry of carbon and nutrients within their resource base. Thus, we expect stoichiometry to contribute to the spatial variance in the demographic parameters of animal communities. Here, we measure how the composition of a litter-nesting tropical rainforest ant community is influenced by spatial variation in environmental stoichiometry relative to litter biomass, a known predictor of ant density. We found the density of ants and their nests were strongly related to litter biomass and carbon: phosphorus stoichiometry. The spatial variation in soil nutrients, which determines leaf litter stoichiometry, was an excellent predictor of nest size in the two most common genera of ants. We found a negative relationship between species' growth rate and local soil stocks of phosphorus. Overall, the density of litter-dwelling ants varied greatly across this tropical forest landscape and environmental stoichiometry can account for limits on ant density independent of the biomass of the leaf litter resource base.     

Diversity of woody species in forest,treefall gaps,and edge in Kibale National Park,Uganda

If specialization influences species presence, then high tropical tree and shrub diversity should correspond with high environmental heterogeneity. Such heterogeneity may be found among different successional communities (i.e., canopy types). We explore species associations in three forest-dominated canopy types, forest, gap, and edge, in Kibale National Park, Uganda and determine environmental, soil and light, differences among canopy types. To determine the strength of differences among forested canopy types, they are also compared to grasslands. Tree and shrub density and species richness using rarefaction analysis were determined based on data from 24 small plots (5 × 5 m) in all four canopy types and 16 large plots (10 × 50 m) in forest and grassland canopy types. Environmental variables were determined along 10 (20 m) transects in the four canopy types. Using analysis of variance and principal components analysis, we demonstrate that forest and gap environments had similar soils, but forest had lower light levels than gap. We also found that grassland and edge were more similar to one another than to forest and gap, but differed in a number of important biotic and abiotic factors controlling soil water availability (e.g., edge had higher root length density of small roots < 2 mm diameter in the top 20 cm than grassland). Using principal components analysis to assess similarities in community composition, we demonstrate that gap and forest had indistinguishable communities and that edge was similar to but distinct from both communities. Complete species turnover only occurred between grassland and the three forested canopy types. Even though overall community composition was similar in the three forested canopy types, in analyses of individual species using randomization tests, many common species were most frequently found in only one canopy type; these patterns held across size classes. These results suggest that despite differences among environments, community composition was similar among forested canopy types, which are likely intergrading into one another. Interestingly, individual species are more frequently found in a single canopy type, indicating species specialization.     

历山自然保护区猪尾沟森林群落植被格局及环境解释

应用TWINSPAN、DCA和DCCA,从植物种,植物群落与环境的生态关系方面,研究历山自然保护区猪尾沟森林群落的植被分布格局,并给予合理的环境解释。结果如下：（1）采用TWINSPAN数量分类方法,将植被划分为9个群落类型。（2）对于特定的研究区域猪尾沟,制约森林群落类型,植物种分布格局的主要因素是海拔梯度,即水、热两个环境因子。（3）DCCA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各植物群落所在环境的海拔梯度,即热量因素,沿第一轴从左到右,海拔逐渐升高,植物群落或植物种对热量要求降低;第二轴主要表现了各植物群落或植物种所在环境的坡度,坡向,即水分和光照因素,沿第二轴从下到上,坡度渐缓,坡向渐向阳。     

Mounding alters environmental filters that drive plant community development in a novel grassland

Earthen mounds are commonly used in ecological restoration to increase environmental heterogeneity, create favorable microclimates and retain soil resources that promote plant establishment. Although mounding is commonly employed in restoration, few microtopography studies focus on the long-term effects of mounding on restored plant community development. We assessed the vegetation and physical environment of earthen mounds installed at a novel grassland ten years after restoration to look for patterns in plant community development. We used permutational multiple analysis of variance (PERMANOVA) to identify differences in plant community composition and the associated mound-driven environmental variables, summer soil moisture and height above peak soil inundation, in relation to mound position. We used indicator species analysis (ISA) to classify the species that defined mound top and intermound space plant communities. We found that mound position drove plot height above flooding and soil moisture while plant community composition was driven by plot height above flooding, summer soil moisture, and mound position. ISA showed that species colonized mound microsites differently: most wetland species occurred between mounds and xeric stress tolerators largely occupied dry mound tops. We visualized these differences with non-metric multidimensional scaling (NMDS) ordination, finding that species sorted out in multivariate space based on mound position. We conclude that mounding can have relatively long-term effects on plant community development, even in highly disturbed, minimally maintained restoration projects.     

汶川地震滑坡迹地植物群落与环境的关系

为了加快汶川地震滑坡迹地人工恢复植被的进程,探讨地震诱发的滑坡迹地植物群落与环境的关系。在5·12地震重灾区北川境内选取29个样地进行植被调查,采用10个环境指标刻画植物群落的地形、空间位置和土壤养分特征;利用TWINSPAN、CCA、DCA和DCCA,分析植物种、植物群落和植物生活型与环境的关系。结果显示:1)研究区的植物群落可划分为9个类型。2)研究区环境变量对植物种的解释量为21.96%,第一排序轴与pH值、海拔、土壤质地相关,反映的是植物种从次生植物群落向原生植物群落变化。通过DCCA分析得出,环境变量对植物群落的排序解释了25.7%,第一排序轴与pH值、海拔、土壤质地的相关较强,反映植物群落按照耐旱、耐贫瘠→人工或先锋植物→未受损的植被变化;第二排序轴与土壤有机质、全氮含量、坡向的相关,反映的是植物群落从草本植物→乔灌草或者灌草植物变化。3)滑坡迹地的植物群落与未受损林地的植物群落物种存在较大差异。     

Environmental,Spatial and Structural Components in the Composition of Mountain Forest in the Bavarian Alps

A combined systematic and stratified sampling design was conducted in mountain forests of the Bavarian Alps to find the principal dimensions of compositional variation of vegetation and their environmental drivers. In 1,505 plots species composition, forest types and soil profiles were recorded. Data from 14 climate stations were included. As we hypothesized that the tree layer is more influenced by management than the understorey and that the former modifies the habitat of the latter, the two matrices were analysed separately and the species composition of the tree layer was used as a structural predictor variable for the understorey. We applied constrained ordination to reveal the main gradients in floristic composition and variance partitioning to examine the portions of climatic, edaphic, spatial and structural components. Ellenberg indicator values and a generalized linear model were used to test whether a significant spatial gradient exists from east to west, the main spatial extent of the investigation area. Forest types were used as an overlay to assess the underlying environmental factors. It turned out that explained variance of the tree layer was considerably lower than in the understorey. Tree layer composition was more influenced by climatic variables than by soil. In the understorey, edaphic and climatic variables contributed almost equally to explained variance, but the tree layer had an additional explanatory power. No continentality gradient could be detected within the investigation area. Plant communities were well separated along gradients of acidity, moisture, nutrients and climate, which broadly confirms the known gradients for montane and subalpine zonal forests in the region. The study provides a quantitative synthesis of the knowledge on a diverse set of community types, which has so far been subject to disparate and sectorial treatment in the Bavarian Alps.     

Development of plant communities after restoration of the Antaibao mining site,China

To investigate the dynamic changes in the artificial vegetation in an abandoned mining site,we analyzed the relationships among community types,environmental variables and community structure in the process of vegetation restoration in the Antaibao mining site,China by survey of the communities and use of biological dating methods.By means of the quantitative classification method (two-way indicator-species analysis,TWINSPAN) and the ordination technique (de-trended correspondence analysis,DCA; and de-trended canonical correspondence analysis,DCCA),the plant communities were classified into seven groups:community Ⅰ,Robinia pseudoacacia + Pinus tabulaeformis-Caragana korshinskii-Agropyron cristatum; community Ⅱ,Robinia pseudoacacia-Hippophae rhamnoides-Artemisia capillaries; community Ⅲ,Ulmus pumila-Elaeagnus angustifolia-Artemisia capillaries;community Ⅳ,Caragana korshinskii-Agropyron cristatum+Artemisia capillaries;community Ⅴ,Hippophae rhamnoides-Elymus dahuricus;cornrnunity Ⅵ,Elaeagnus angustifolia+Hippophae rhamnoides-Brassica jucea;community Ⅶ,Hippophae rhamnoides+Elaeagnus angustifolia-Salsola collina.We conclude that the community types and diversity are mainly influenced by the succession time and the soil organic matter content.The forest community is more adaptable to the special inhabitation than the shrub community.