Validation of the Finnish forest types by numerical methods illustrated by means of two sets of relevé data

Examples show that two clustering programs (GROUPAGE, TABORD) group the forest vegetation into clusters with about the same results as obtained by a traditionally working plant sociologist assigning it to the Finnish forest site types. The best result is achieved by using both of these programs together with an additional ordination program (ORDINA). The differences when all three analyses are taken into account depend on the fact that there are often some transitional relevés in the material. In a few cases a new type determination for the relevé might be justified. The clustering methods show often groupings into smaller units (variants) inside the types, units which are rarely used in the Finnish forest type system.     

黑龙江省不同地点蒙古栎林生态特点研究

通过对黑龙江省６个地点的天然蒙古栎林的结构和更新特点的分析,蒙古栎林可划分为不同特点的蒙古栎群落,即纯蒙古栎群落、蒙古栎桦树群落、蒙古栎槭树群落、蒙古栎红松群落和蒙古栎松混交林群落,其演替趋势如下：红蒙古栎群落、蒙古栎桦树群落至蒙古栎槭树落、蒙古栎红松群落,再至蒙古栎红松混交林群落,蒙古栎群落类型的多样性主要反应群落不同的演替阶段,造成蒙古栎群落多样的原因是人类活动和自然因素作用的结果,随着群落的演替,蒙古栎的优势地位逐渐被消弱,乔木种类丰富度增多,草本种类丰富度增多;蒙栎的相对密度下降,林内环境由于干燥逐渐变中性至较湿润,蒙古栎幼苗和幼树在总幼苗和幼树中所占的比例下降,耐荫物中色木槭等的幼苗和幼树所占比例上升;在演替过程中,蒙古栎分布格局－聚集分布的聚集程度逐渐降低,并向随机分布的方向发展。     

广西金钟山自然保护区主要植被类型的特征

金钟山自然保护区计有种子植物101科273属514种,落叶栎林分布面积最广。随海拔升高,植被依次呈现出4个分布带:沟谷落叶阔叶林、沟谷常绿阔叶林、常绿落叶阔叶混交林和落叶阔叶林、山地苔藓矮林和山地常绿阔叶林。该区主要有4个分布区类型:世界分布、热带分布、温带分布和中国特有分布,其中热带分布占总属数的75.21%,表明本保护区的植物分布具有热带性质。其天然植被类型可划分为5个植被型组,7个植被型含暖性针叶林、暖性落叶阔叶林、常绿落叶阔叶混交林、常绿阔叶林、竹林和草丛,2个植被亚型含南亚热带山地常绿阔叶林、山顶阔叶矮林,以及33个群系。     

Testing the predictivity of ecological indicator values. A comparison of real and `virtual' relevés of lichen vegetation

A complex database on the lichens of Italy was used to combine ecological indicator values assigned to each species (pH, eutrophication, light and aridity), in such a way as to simulate `virtual habitats' from a beech forest of northern Italy. For each habitat, a list of species was obtained (`virtual relevé'). A matrix of real and virtual relevés was submitted to classification and ordination, obtaining six main community-types, all of which include both real and virtual relevés. Two ordinations of species were carried out, one on the matrix of real relevés, the other on that of virtual relevés: their comparison shows that the consistency and the resolving power of the indicator values was high, but it also permits to detect and correct some errors. The results indicate a high predictivity of the indicator values for constructing ecological scenarios.     

Partitioning an elevation gradient of vegetation from southeastern Ethiopia by probabilistic methods

Vegetation and environment have been analyzed along an altitudinal gradient in Harena Forest, Bale Mountains National Park, southeastern Ethiopia. Vegetation data include numbers of each tree and shrub species and cover-abundance values of each herbaceous species. Environmental data comprise edaphic factors, altitude and topography. The two vegetation layers data were analysed separately.Probabilistic similarity coefficients were computed between the relevés, and these values were used in subsequent computations for classification and ordination. Two sets of stratocoena, comprising 6 types each, derived on the basis of separate analyses of tree-shrub and herb layers of the forest were recognised. A combination of the two sets of stratocoena produced a total of 11 vegetation types. Environmental fuzzy set analysis was applied to determine the strength of the relationship of the relevés to the environmental factors. Autocorrelation analysis was applied to the eigenvectors of probabilistic similarity matrices and environmental data. Altitude appears to be more important thant the other environmental factors in controlling the zonation of the forest. Other important environmental influences on the vegetation include pH, organic matter content and texture of the soil. It is suggested that the whole forest be included in the National Park to create suitable conditions for adequate protection.Abbreviations EFS Environmental fuzzy sets - PROSIM Probability similarity index - PCA Principal components analysis     

Ecological species groups in forest communities in South Belgium

Cluster analysis, correspondence analysis and the method of ecological profiles were used to determine and characterize ecological species groups in woodlands in South Belgium. Two data sets were used, one composed of 260 relevés, the other of 130 relevés with soil analyses (A1). Correspondence analysis points out the most important factors influencing the floristic composition of the stations.     

New similarity indices for the assignment of relevés to the vegetation units of an existing phytosociological classification

Every proposed vegetation classification is sooner or later confronted with an accumulation of new data, which has to be assigned to existing vegetation units. Calculation of similarity indices between new relevés (vegetation plots) and constancy columns of established vegetation units is a suitable method for computerised assignment of relevés to these units. This paper compares several similarity indices using simulated data set where either randomly distributed or diagnostic species prevail in the species composition of the tested relevé. Traditional indices, based only on species composition, produce different results than similarity indices that consider species fidelity. However, both types of indices failed in some situations and thus cannot be widely accepted as suitable methods of additional relevé assignment. Therefore a combined Frequency-Positive Fidelity Index (FPFI) is proposed. This new index includes compositional similarity of an assigned relevé with vegetation unit and retains the advantages and lacks the disadvantages of tested indices. The calculation of all these indices is available in the JUICE program (http://www.sci.muni.cz/botany/juice.htm).     

Influence du traitement sylvicole sur la flore forestiere: Cas de la futaie et du taillis-sous-futaie

Summary In a previous study, 772 floristics relevés, made in a large forest on calcareous soils (north-east France), had been treated by factorial analysis of correspondences in order to establish a site typology. The third axis separated chiefly Fagus and Quercus, which are very common in the forest, and various other ligneous or herbaceous species (see fig. 1). Two groups of relevés, homogeneous as for edaphic conditions, were choosen, having a significant position on this axis (with either positive or negative values). From this, floristic tables have been elaborated; they show clearly the influence of silvi culture (here high forest or coppice-with-standards) on part of both ligneous and herbaceous flora. Considering plant sociology, it appears that treating a stand as a coppice-with-standards can convert a Melico-Fagetum typicum (Eu-Fagion) into a Querceto Carpinetum typicum (Fraxino-Carpinion), and a Carici-Fagetum (Cephalanthero-Fagion) into a Querceto-Carpinetum primuletosum (Fraxino-Carpinion). Fortunately a large number of species are not influenced by the silviculture; this allows the identification of isopotential sites. Possible ecological causes are briefly discussed.

Nomenclature suivant: P. Fournier, 1961. Les quatre flores de France. Edition P. Le Chevalier, Paris. 1154 p.     

佛坪国家自然保护区地面生苔藓植物物种多样性

通过对秦岭南坡佛坪国家自然保护区地面生苔藓植物的调查,采用相似性系数、重要值、多样性指数对其进行物种多样性的研究。结果表明:29个样地内地面生苔藓植物共33科69属189种,包括苔类植物7科8属15种和藓类植物26科61属174种,其中青藓科是最优势的科。落叶阔叶栎(Quercus)林下地面生苔藓植物的物种多样性最高,其次是落叶阔叶桦(Betula)林带、竹林、针叶林和沟谷岩石,杜鹃(Rhododendron)灌丛带的最低。落叶阔叶栎林带和落叶阔叶桦林带的种相似性最高,杜鹃灌丛与其它植被带的种相似性都很低。研究表明秦岭南坡的佛坪国家自然保护区内,低山地区的落叶阔叶栎林带是该地区苔藓植物多样性的分布中心,是物种多样性保护的关键地带;亚高山地区杜鹃灌丛带的苔藓植物物种多样性虽然不高,但种类明显不同于别的地带,所以也应是苔藓植物多样性保护值得注意的地带。     

不同林分类型对昆虫群落多样性的影响

为研究近自然森林经营下的华北落叶松人工林不同林分类型对昆虫群落多样性的影响,以塞罕坝自然保护区内的华北落叶松纯林和混交林作为研究对象,对6种不同林分类型中的昆虫群落结构进行了研究。共获得昆虫标本9542头,隶属于7目,68科,187种,以双翅目、半翅目和鞘翅目为优势类群。研究结果表明:6种林分类型中的昆虫在物种和个体数上存在差异,相似性分析显示群落结构均不相似;群落多样性指数分析表明华北落叶松纯林和其它类型的混交林均具有较高的丰富度指数和多样性指数;主成分分析表明各林分类型中捕食性类群和寄生性类群是影响昆虫群落结构的主要因素,且捕食性类群和寄生性类群对植食性类群的控制作用较强;稳定性分析显示6种林分类型昆虫群落结构均具有较高的稳定性。     

影响广东黑石顶树附生苔藓分布的环境因子

通过对广东省黑石顶自然保护区内5个2500 m2样地内树附生苔藓的调查及有关环境因子的测定,研究了树附生苔藓的分布格局及其与环境因子的关系.树附生苔藓在不同高度的分布存在一定梯度,20 cm高处树附生苔藓的种类数与盖度均大于60 cm及更高处,且其群落优势种的数量组成与后者存在较大差异.不同树种附生苔藓盖度和种数差异较大.基于附生苔藓植物的盖度进行DCA排序及聚类分析将树种分成四组,马尾松(Pinus massoniana)因具有两种特有的网藓(巴西网藓Syrrhopodon prolifer和鞘刺网藓S.armatus)单独一组,福建青冈(Quercus chungii)亦与其余各种的差异均较大,形成一组,其余阔叶树种根据其所处的森林类型分成两组,针阔叶混交林内的阔叶树种和次生阔叶林内的阔叶树种各形成一组.对环境因子及树皮含水量和pH的分析显示,垂直梯度上空气湿度的差异可能是造成附生苔藓在不同高度分布差异的主要影响因子之一,不同树种附生苔藓的差异在一定程度上受树皮pH的影响,而与树皮含水量无关.同一树种上树附生苔藓的分布又在一定程度上受森林类型的影响.     

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。     

A phytosociological survey of the boreal forest (shape Vaccinio-Piceetea) in North America

A survey of syntaxa of vegetation of North American boreal forests (class Vaccinio-Piceetea) is presented. This phytosociological survey, carried out combining the Braun-Blanquet method with numerical syntaxonomical analyses (cluster and correspondence analysis), describes the associations of the North American boreal forests, which have several species, varieties or vicariant species in common with their Eurasian counterparts, and can be placed in the class Vaccinio-Piceetea. By means of tabular and multivariate analyses, 2084 North American relevés were compared with 3273 relevés from European, Japanese and Korean boreal forest, to describe and typify 4 orders, 10 alliances and 37 associations. Diagnostic tables, ordination, clustering, and climatic, edaphic and biogeographical data were used to show floristic affinities among these syntaxa and interpret their distribution areas. Syntaxa were briefly characterized by their floristic composition, physiognomy, succession, zonation, and biogeographical distribution.     

Impact of grazing on the species richness of plant communities in Mediterranean temporary pools (western Morocco)

The impact of grazing on the vegetation of Moroccan temporary pools has been studied at 2 scales: regional (inter-pools) and local (intra-pools). Half of the 16 forest pools studied is located in a reserve and ungrazed. The other half, located within public forest, is grazed. Vegetation relevés coupled to water-depths measurements were carried out in each pool. The results showed a significant effect of grazing on both scales of analysis. This effect was found in the species composition of the vegetation, which differed between the 2 types of pools, and in the lower species richness and abundance of plant species in the grazed pools. These differences are interpreted as resulting from the selection by herbivores and the differential tolerance of species to disturbance. These impacts are likely to expose certain species to local extinction by reducing their populations.     

Interspecific associations in phytosociological data sets: how do they change between local and regional scale?

Interspecific associations detected in phytosociological data sets sampled in local areas can reflect locally specific combinations of environmental factors and may thus differ from the interspecific associations existing on a regional scale. As a result, vegetation units derived from numerical classifications of local data sets can accurately reflect local environmental gradients, but their boundaries or spectra of diagnostic species must be frequently adjusted when transferred to the regional scale. Local vegetation classifications can be useful for some purposes, but regional classifications are superior, as they facilitate communication among the researchers from different areas. We demonstrated changes in interspecific associations between regional and local scale, using a data set of 14 589 relevés of herbaceous vegetation of the Czech Republic, and 16 local subsets of this national data set. We focused on sociological species groups, derived statistically in the national data set. Changes in coherence of these groups when applied to the local data sets were described on the basis of statistical association between the relevés containing some species of these groups and the species belonging vs. not belonging to these groups. The results were summarized using the principal components analysis (PCA). In addition, relevé data sets were compared with respect to presence/absence of sociological species groups, using the principal coordinate analysis (PCoA). The results of PCA and PCoA were compared by Procrustean analysis. Local data sets differed from the national data set to different extent. The national data set was more remote to the local data sets if the analysis focused on the coherence of species group rather than on presence/absence. The species groups from the national data set retained most of their coherence in low-altitude hilly landscapes with thermophilous flora, i.e., the most diverse landscape type of the Czech Republic. On the other hand, many species groups from the national data set could not be recognized in mountainous areas or flat lowlands. These results suggest that interspecific associations existing on regional scale are best reproduced in those local areas which have a high habitat heterogeneity or which have a central position along the major gradients existing on regional scale.     

A method for the analysis of temporal changes in vegetation pattern at the landscape level

A new approach to study temporary changes in small landscape units is proposed, based on vegetation-complex relevés (sigma relevés). The method is introduced using extensively grazed or abandoned heathland and Nardus-sward landscapes in the Black Forest as examples. Thirty-six sigma relevés of the years 1979–80 are compared with those of 1989–90. Each of the compared plot areas covers on the average 2–4 hectares, and has a diversity of about 20 different vegetation types. The vegetation complex relevés can be ordered to 3 different types which characterize landscape ecological zones dependant on former rural management.As a result of the comparison 2 main developments which have a spatial differentiation in the Black Forest are confirmed and documentated:

Clusla: A computer program for the clustering of large phytosociological data sets

Summary CLUSLA, a computer program for the clustering of very large phytosociological data sets is described. It is an elaboration of Janssen's (1975) simple procedure. The essence of the program is the creation of clusters, each starting with one relevé, as the relevés are entered in the program. Each new relevé that is sufficiently distinct from already existing clusters is considered a new cluster. The fusion criterion is the attainment of a certain level of (dis-) similarity between relevé and cluster. Bray and Curtis' dissimilarity measure with presence-absence data was used.The program, written in FORTRAN for an IBM 370–158 system, can deal with practically unlimited numbers of relevés, provided the product of the number of primary clusters and the number of species does not exceed 140.000. We adopted maxima of 100 and 1400 respectively.After the primary clustering round a reallocation is performed. Then a simple table is printed with information on the significance of occurrence of species in clusters according to a chi-square approach. The primary clusters can be treated again with a higher fusion threshold; or approached with more elaborate methods, in our case particularly the TABORD program.The program is demonstrated with a collection of 6072 relevés with 889 species of salt marsh vegetation from the Working-Group for Data-Processing.Contribution from the Working Group for Data-Processing in Phytosociology, International Society for Vegetation Science. Nomenclature follows the Trieste system, which will be published later.The authors are very grateful to Drs. Jan Janssen, Mike Dale, László Orlóci and Mike Austin for their comments on drafts of the program, and to Wil Kortekaas for her help in the interpretation of the tables.     

A phytosociological survey of the Irish Molinio-Arrhenatheretea using computer techniques

Summary The Irish approach to the computer processing of grassland relevés is introduced. A suite of programs in Fortran IV has been developed for the purpose. The preparation and analysis of the relevés using these programs is explained. The cost and ecological effectiveness is discussed. It is concluded that the approach is not radically different to the familiar Braun-Blanquet technique of tabular comparison of relevés.Contribution from the Working Group for Data-Processing in Phytosociology, International Society for Vegetation Science.     

山西蟒河猕猴国家级自然保护区蛾类多样性

选择山西蟒河猕猴国家级自然保护区针阔叶混交林、阔叶落叶林、杂木林和灌木林4种植被类型为调查样地来初步了解蛾类群落结构及多样性。共采集蛾类标本4709只,隶属24科184种,其中螟蛾科种类和个体数量最多。在4种植被类型中,灌木林的蛾类种数最多,有20科132种,灌木林中螟蛾科为优势科;阔叶落叶林中最少,14科74种,尺蛾科为优势科;针阔叶混交林和杂木林居中,其中前者优势科不明显,后者以草螟科占优势。对4种植被类型中蛾类物种丰富度、多度、多样性和均匀度指数进行了计算和分析,结果表明:蛾类的多度指数在阔叶落叶林中显著低于其余3种植被类型;蛾类的丰富度、多样性和均匀度指数在灌木林中均最高,在针阔叶混交林和杂木林中则相近。蛾类种-多度曲线在针阔叶混交林、杂木林和灌木林中符合对数正态分布模型,而在阔叶落叶林中不符合对数正态分布模型。