Influences of the individualistic concept of vegetation on syntaxonomy

The individualistic concept of vegetation is based on three principles: (1) vegetation continuum, (2) ecological and chorological individuality of species and (3) multidimensional variability of vegetation. All principles reflect phenomena existing in nature. The conclusions arising from these principles are these: (1) plant communities (phytocoenoses) are not natural objects (wholes) as such but merely mixtures of plant individuals coexisting on the same site as the result of migration and environmental selection, (2) the classification of vegetation is quite arbitrary if not pseudoscientific, and (3) vegetation phenomena can be reduced to phenomena of plant individuals.The integrated concept of vegetation considers the phytocoenoses as real functional systems (wholes) where plant populations are integrated both by the environment and by interactions among and within plant populations. The principles of the individualistic concept, but not the above conclusions arising from them, are compatible with the integrated concept. Phytocoenoses limit the individualistic performance of species through restriction of ecological amplitudes and shifting of ecological optima (as compared with physiological amplitudes and optima). The individualistic behaviour of species does not exclude the formation of coenological groups of species which form a basis for the classification of vegetation according to floristic-coenological criteria. Under natural conditions, plant communities are usually interconnected by transition zones to form a vegetation continuum. Phenomena of the vegetation continuum do not cause greater difficulties in syntaxonomy than those of polymorphic taxonomic groups in plant taxonomy.     

Ecological amplitude in Silene nutans in relation to allozyme variation at the western margin of its distribution

Abstract. At the western border of its geographical range, Silene nutans (Caryophyllaceae) has evolved two groups of parapatric populations showing distinct allozyme patterns and apparently occurring on different bedrock types. This study tests the hypothesis that these groups represent edaphic ecotypes. With this in view, the ecological amplitude of 36 populations of Silene nutans from Belgium was investigated and their synecology specified using vegetation composition and soil parameters; Ellenberg indicator values were used for ecological interpretation of the vegetation analyses. The results provide evidence that allozyme and habitat variations are correlated, the two groups occurring on contrasting soil with distinct vegetation types. One group is restricted to alkaline soils and typically occurs in open calcareous grasslands, fringes and scrub. The other group is characterized by wider autecological and synecological ranges with a bimodal pH- distribution, occurring on two kinds of siliceous soils: (1) neutral soils, supporting vegetation with a high species richness comprising many mesophilous species, and (2) CaCO₃ -free bedrocks characterized by acidophilous, species-poor, open dry grasslands and woodlands. It also appears that factors not related to soil chemistry, such as microclimate, are involved in the ecological specialization of the two ecotypes. It is argued that these ecotypes exemplify adaptive radiation and parapatric speciation at the margin of a species distribution area.     

Quantified ecology and co-occurrence of Mediterranean woody species in a landscape context

Understanding co-occurrence and ecological affinities of plant species is essential in vegetation and landscape ecology. In a case study, we analysed distribution records with high data density of all commonly occurring tree and shrub species of Crete (Greece) with offshore islands. We present the ecological range of widespread and more range-restricted species in the Mediterranean area, visualising their affinities for macroclimate, topoclimate and geology by means of an ecological heatmap. Complete linkage classification of combined ecological spectra revealed groups of generalist species with broad ecological amplitude, groups related to zonal vegetation and chiefly dependent on elevation, and species of azonal vegetation grouped mainly by topography and substrates. Species and ecological groups with high affinity may be indicative of (a combination of) site features. Our re-evaluation of plant distribution records links plant geographical and ecological information, and thereby complements expert habitat and species assessments. Our case study provides deeper understanding of ecological patterns, and at the same time allows for comparison and extrapolation to other biomes.     

Numerical analysis of mire vegetation at Åsenmyra, Engerdal, Central Southern Norway and comparison with traditional Fennoscandian paludicology

The investigation area has been examined by means of a regularly-spaced sampling technique. With the sample plots as attributes, association analysis (ASSI/AN) and inverse information analysis (INFO) have been employed to estimate associations between pairs of species (ASSI/AN) and to establish species groups (INFO). The 50 most frequently occurring species in the sample set were selected for these purposes. Based on INFO and ASSI/AN results and ecological measurements' indication, fourteen species groups have been established and discussed.
Divisive information analysis (DIVINF) has been employed in the classification of sample plots. The 75 most frequently occurring species were selected as attributes. Twenty DIVINF groups were established. Similarity coefficients were calculated between all these groups in order to reexamine their internal relationships. Based on these coefficients and based on the species groups and the ecological measurements' indication, DIVINF groups have been linked to establish vegetation blocks, which are regarded as the basic vegetation units in the present study. Traditional Fennoscandian phytosociological notions are used in the discussion of the four blocks and in comparisons of the blocks with other mire vegetation communities described.     

The distribution of ecological species groups in Fagetum communities of Caspian forests: Determination of effective environmental factors

Aim of the research was the recognition of ecological species groups in beech forests south of the Caspian Sea (Northern Iran) and the determination of the main effective environmental factors explaining the distribution of plant ecological groups. Selective stratification sampling was used to locate samples. A total of 120 samples (400 m² each) were selected in Fagetum communities within the study area. At each sample, a floristic list of the plot and an estimate of percent cover and abundance of all vascular plants were recorded in separate strata using the Braun-Blanquet scale. At the center of each vegetation plot, two soil samples were taken of 0–10 and 10–30 cm depth levels for physico-chemical analyses. Cluster analysis was used for the classification of vegetation samples and Multi-response Permutation Procedure (MRPP) was used to test the hypothesis of no difference between ecological groups in the species space. Indicator species analysis was used to identify indicator species for each group. A Tukey test was used to compare environmental variables among groups. Detrended Correspondence Analysis (DCA) was used to analyze the relationships between the ecological groups and environmental variables.     

白洋淀蝗虫分布调查及其防治

1998～ 2 0 0 2年对白洋淀蝗区的蝗虫种类、分布、优势种群及蝗区水文、植被、土壤、天敌等进行了调查研究。调查表明 ,白洋淀蝗区有蝗总科昆虫 3 0种 ,隶属 6总科、2 2属 ,分布于白洋淀淀内湖泊蝗区、淀边内涝蝗区和淀外河泛蝗区 ;明确以东亚飞蝗Locustamigratoriamanilensis (Meyen)为主的 5个蝗虫优势种群及生活史 ,并根据不同蝗区类型 ,提出了蝗区治理区划、生态治理技术、应急化学防治等 3项防治技术和“两改一加强”防治手段     

Herbal vegetation in shelter belts composed of various species in Shira steppe, Khakasia

Shelter belts composed of various species were grown under arid conditions of the Shira steppe, Khakasia. The results of the investigation of species diversity, distribution of herbs over ecological groups, and regularities of species composition dynamics, structure and biomass of ground vegetation in shelter belts are reported. The influence of the ground vegetation on the tree growth in shelter belts is considered.     

Foraging height and landscape context predict the relative abundance of bird species in urban vegetation patches

In Australian urban environments, revegetation and vegetation restoration are increasingly utilized conservation actions. Simple methods that help assess the utility of urban vegetation for bird species will help direct this effort for bird conservation purposes. We therefore examine whether ecological principles can be used to predict, a priori, the relative abundance of different bird species in urban vegetation. Our model proposes that a bird species will be in greater abundance where vegetation structure better reflects its foraging height requirements, and this relationship will be moderated by the landscape context of the patch. To quantify and test this model, we created an index to rank existing and revegetated urban vegetation sites in order of greatest expected abundance for each of 30 bird species. We tested this model, alongside two simpler models which consider landscape context and foraging height preferences alone, using bird abundance data from 20 woodland remnants and 20 revegetated sites in Brisbane, Australia. From these bird abundance data, we calculated the relative abundance of each species between the top‐ranking sites and lowest‐ranking sites. The model which incorporated both foraging height requirements and landscape context made predictions that were positively correlated with the data for 77% of species in remnant vegetation and 67% in revegetation. The results varied across species groups; for example, we achieved lower predictive success for canopy foraging species in the less mature revegetation sites. Overall, this model provided a reasonable level of predictive accuracy despite the diversity of factors which can influence species occurrence in urban landscapes. The model is generic and, subject to further testing, can be used to examine the effect of manipulating vegetation structure and landscape context on the abundance of different bird species in urban vegetation. This could provide a cost‐effective tool for directing urban restoration and revegetation efforts.     

不同荒漠化阶段植被生态特征对土壤环境因子的响应——以民勤荒漠绿洲过渡带为例

荒漠绿洲过渡带是荒漠化和绿洲化两种地理过程共同影响的生态交错区,是恢复生态学重点关注的区域。利用第五次全国荒漠化和沙化监测数据,采用方差分析和冗余分析,研究了民勤荒漠绿洲过渡带4种不同荒漠化发展阶段的植被生态特征和土壤环境因子的变化规律与相互关系。结果表明:(1)随着荒漠化的发展,土壤环境因子中,除有效土层厚度逐渐变浅外,风蚀痕迹占地率、表土砾石含量、盐碱斑占地率和坡度均呈现增加的动态趋势;植被因子中,除优势种盖度与植被总盖度的比值逐步增加,物种丰富度、优势种多度等其他指标均表现出明显的下降特征;(2)土壤环境因子中,有效土层厚度在4种荒漠化阶段对植被生态特征的影响程度达显著水平(P0.05),风蚀痕迹占地率在轻度、中度和重度阶段是植被生态特征变化的主导驱动因子。其他因子在多数荒漠化阶段与植被生态特征相关性不显著;(3)相比其他荒漠化阶段,中度阶段中植被生态特征对土壤环境因子的响应更加敏感,应是荒漠化防治重点关注的阶段。     

A study of habitat conditions of the macrophytic vegetation in selected river systems in western Lower Saxony (Federal Republic of Germany)

In connection with a phytosociological survey of running water macrophytes in Lower Saxony, ecological investigations were carried out in selected river systems. Within these systems, 43 sampling sites were studied. The vegetation of the sampling sites was classified by means of cluster analysis into 7 groups, 3 of which occurred on the diluvial plains and 2 in the coastal marsh area only. Forty-one parameters were measured 3–7 times covering 2 vegetation periods. In the first instance, the structure of the data was carefully studied by bivariate correlation analysis and factor analysis. A high number of significant correlations was detected, which indicates difficulties in ecological interpretation. Temporal variation of the parameters measured was also studied, and they were classified into 3 groups according to stability. For a study of the relationships between the vegetation and the ecological parameters, the data set was split into 5 subsets (physical data, water chemical data, interstitial water chemical data, sediment characteristics, and a mixed set of simple field data). The relationships of each subset to the vegetation was studied separately using cluster analysis. The mixed data set FIELD showed the highest degree of similarity to the vegetation clustering. Analysis of variance was carried out in order to find out which variables differ most among the vegetation types. The best differentiation qualities were shown by some physical and water chemical parameters (oxygen content, turbitity, current velocity, acidity, calcium). This result can only be interpreted ecologically in connection with the intercorrelations observed. The ecological behaviour of some species of medium frequency was also studied in detail by means of analysis of variance. The means of all parameters for occurrence and non-occurrence were compared. In the case of Ranunculus peltatus Schrank, Myriophyllum alterniflorum DC and Elodea canadensis Michx., several differentiation variables could be detected. Finally, the zonation of two rivers was studied in detail by comparing the vegetation sequence with important physical and chemical parameters. The interaction between these parameter groups is clearly shown. Physical parameters like current velocity are responsible for the basic zonation, whilst chemical parameters can modify the zones to a large extent. The necessity for a comprehensive approach to such types of data sets, including profound structural data analysis, is stressed in the discussion. The special problem of relating phytosociological and ecological data is discussed. The methods used are explained and possible objections are noted. The difficulties of using the habitat ecological results for bioindication purposes are outlined. Spatial autocorrelation, vegetation dynamics, interactive processes between the system parameters and the genetic variability of species have to be considered as the main problems in this special application. Nevertheless, the study produced some results which indicated the significance of physical, chemical and sediment parameters for macrophyte growth in the type of waters under investigation, and suggested subject areas for future research.     

On the concept of vegetation class in phytosociology

Abstract. The vegetation class is generally accepted as the highest category in vegetation taxonomy. Vegetation classes, following the tradition, are defined mainly on the basis of character species. However, these are sometimes relatively rare and not always really representative of the ecological conditions of plant communities included in the class. In the present study the possibilities are discussed for a more comprehensive definition of the class, including spatial structure and environmental characteristics of the vegetation and the geographical distribution of character species. These include criteria with practical value, in particular for the understanding of vegetation in tropical areas. Some cases of well-known vegetation classes are discussed; in most of them the ranges of single character species and the range of the class as a whole largely coincide.     

Vole mound effects and disturbance rate in a mediterranean plant community under different grazing and irrigation regimes

A factorial field experiment was used to assess the influence of soil-disturber mammals in the structure of a 9-year-old Mediterranean annual plant community subjected to different sheep grazing and irrigation regimes. We estimated the disturbance rate (mound building activity) by Mediterranean voles, their effects on vegetation and the mechanisms of these effects during a period of vole outbreak. The effects on vegetation were analysed at the levels of species, functional groups and plant community. Disturbance rate was high and voles can disturb the entire soil surface once every four or five years. The availability of certain trophic resources (perennial plants) appeared to drive vole expansion in the experimental plots and it was independent of the irrigation and grazing treatments. Mound building activities largely affected vegetation but conserved plot differences. Total vegetation cover, absolute cover of all functional groups, mean vegetation height and species richness were less on mounds than on undisturbed ground. These effects did not change the relative abundance of annuals, perennials, grasses and forbs. Only the relative abundance of small-seeded species decreased on mounds. As the proportion of these seeds was similar in both types of patches, we suggest that small-seeded species had more difficulties for germinating or emerging when they are buried during mound formation. Irrigation and sheep grazing promoted large changes in the vegetation parameters but these effects were, in general, similar on mounds and undisturbed ground. Our results show that the availability of germinable seeds may be the major limitation for mound revegetation, probably due to the scarcity of seeds existing at the depths from which soils are excavated. Our results also suggested a resource limitation on mounds. The results provide additional evidence that soil disturbances by small herbivore mammals exert relevant ecological effects on abandoned Mediterranean croplands. We discuss the ecological implications of vole mound-building activities for plant succession, plant species conservation and forage resource availability for livestock. This revised version was published online in June 2006 with corrections to the Cover Date.     

海南岛尖峰岭的植被垂直带及林型

本文研究了海南岛尖峰岭的植被垂直带和植被类型的分布与特点,探索热带林林型分类的方法和依据,对尖峰岭划分了四个植被垂直带,六个植被类型,十五个林型组和二十五个林型,为合理经营及开发利用尖峰岭的森林提供科学依据。     

Strain and vegetation effects on local limiting resources explain the outcomes of biotic interactions

Positive interactions are hypothesized to increase with stress (stress-gradient hypothesis, “SGH”), which is defined in terms of standing biomass at the community level. However, recent evidence suggests that facilitation may decrease or remain constant as stress increases. Several reasons for this discrepancy are possible: (i) the outcomes of biotic interactions depend on the component of the fitness considered; (ii) they are influenced by how vegetation affects local limiting resources; (iii) within a particular community, only species that are deviated from their physiological optima are likely to be facilitated. In a removal experiment, we quantified the deviations of species in subalpine grassland from their physiological optima, defined here as species-level “strain”, and examined whether strain and vegetation effects on local resources can explain the outcome of biotic interactions. The experiment was performed along a gradient of standing biomass driven by contrasting land use and resource availability, and used five grass species with contrasting traits and ecological optima. Strain for each species was estimated by comparing growth without vegetation (target species only submitted to local abiotic factors) to growth in optimal conditions (under controlled conditions in an experimental garden). The outcomes of biotic interactions, recorded in terms of survival and growth, could be predicted from the data about strain and vegetation effects on local limiting resources (light and water). Only highly strained species were affected by facilitation, which occurred when the surrounding vegetation alleviated the constraining factors. On the other hand, standing biomass was poorly related with the outcomes of biotic interactions. The “SGH” was only partially validated with growth data when strain and vegetation effects co-varied with standing biomass. As a consequence, strain (at species level) represents a mechanistic basis which could improve the prediction of the outcomes of biotic interactions along ecological gradients.     

Ecological indicator values and life history traits of terricolous lichens of the Western Carpathians

Plant indicator values are widely used in ecological studies, but they are not well developed for cryptogams, what prevents their application in some environments such as lichen-rich habitats. The aim of this study was to determine the ecological indicator values of terricolous lichens occurring in the Western Carpathians. A total of 271 lichen taxa from the eastern part of Central Europe in Czech Republic, Slovakia, Hungary and Austria are listed and evaluated. Their known indicator values for light conditions, climate (temperature, continentality), substratum (humidity, soil reaction-pH, nutrients, eutrophication) were reviewed or modified, and original values were established for taxa with missing information. Besides the traditional ordinal scale, the index of variability was established to distinguish between generalists and specialists in particular applications. Our list further contains important species traits such as ecological strategies (growth and life forms, photobiont type, substrate, reproduction) and geographic values (geographical elements, threat, frequency) allowing applications in functional ecology and macroecology. Our database can be easily associated with widely used software for the analysis of vegetation data allowing the indication of ecological conditions in lichen-rich vegetation types in currently developed large-scale vegetation surveys.     

Spatial congruence between ecotones and range-restricted species: implications for conservation biogeography at the sub-continental scale

Aim To examine whether at a sub‐continental scale range‐limited species tend to occur close to areas of transition between vegetation boundaries more often than expected by chance. Location South Africa and Lesotho. Methods We examined the relationship between the distance of a grid square to ecological transition areas between vegetation types and both avian and frog range‐limited species richness in the quadrat. We used quadrats at a spatial resolution of quarter degree (15′ × 15′≈ 676 km²). Spatial congruence between areas representing range‐restricted species and those representing ecological transition zones was assessed using a random draw technique. Results Species richness and range size rarity are generally negatively correlated with distance to transition areas between vegetation communities when analysed for the whole region for both groups. Although this relationship becomes weaker after controlling for environmental energy and topographical heterogeneity, the explanatory power of distance to transition areas remains significant, and compared to the different biomes examined, accounts for most of the variation in bird richness (20%), frog richness (18%), range‐restricted bird species (17%) and range‐restricted frog species (16%) in the savanna biome. The random draw technique indicated that areas representing range‐restricted species were situated significantly closer in space to those areas representing transition areas between vegetation communities than expected by chance. Main conclusions We find that at the sub‐continental scale, when examined for South Africa, areas of transition between vegetation communities hold concentrations of range‐limited species in both birds and frogs. We find that South African endemic/range‐limited birds and frogs are located closer to ecological transition zones than endemics and non‐endemics combined. This has important implications for ongoing conservation planning in a biogeographical context.     

Ecological conditions on the post-solifluction areas and their role in the forming of primary succession

We studied the ecological conditions forming on the solifluction areas often occurring in cryolithic zone of Central Evenkia. A significant change of microenvironment was registered on some solifluction “microecosystems” that differ sharply form the control ones in plantation. The ecological conditions formed in these areas result in the change of species composition of vegetation and its diversity. However, we revealed no significant differences of separate ecological groups depending on hydrothermal and trophic conditions.     

青藏高原植物群落样方数据集

为便于了解青藏高原植被特殊物种组成、群落特征及分布格局, 该文利用2018-2021年在青藏高原不同区域内调查的338个样地、共758个样方的数据, 分析了高原植物群落的物种组成、区系特征和植被分类, 整合形成青藏高原植物群落样方数据集。结果表明: 青藏高原高寒和温性植物群落758个样方中, 共有植物65科279属837种; 其中, 物种数最多的5个科依次是菊科(134种)、禾本科(88种)、豆科(75种)、蔷薇科(43种)和莎草科(40种), 物种数最多的5个属依次是蒿属(Artemisia, 29种)、马先蒿属(Pedicularis, 27种)、风毛菊属(Saussurea, 25种)、黄耆属(Astragalus, 23种)和早熟禾属(Poa, 23种)。植物区系主要由温带(145属)和世界广布(36属)的成分所组成。物种的生长型以草本(83.51%)和灌木(10.87%)为主, 草本和木本的生活型分别以多年生草本(88.23%)和落叶灌木(83.67%)为主。338个样地可以划分为4个植被型组, 10个植被型, 20个植被亚型, 78个群系组和117个群系, 其中草原群系34个, 草甸群系33个, 荒漠群系33个, 灌丛群系14个和针叶林群系3个。该数据集覆盖青藏高原绝大部分高寒灌丛、高寒草原、高寒草甸、高寒荒漠、温性草原和温性荒漠植被区域, 可为研究高原植被特征和地带性分异规律, 气候变化和人类活动对高原植被的影响及其生态恢复提供坚实的数据基础, 同时为下一代中国植被图的更新提供参考。     

乌拉特荒漠区植被类型及土壤特征

以乌拉特荒漠为研究区,通过10 km×10 km网格均匀布设点位,采用样方法对自然植被展开调查并对研究区土壤特征进行分析.结果表明:(1)研究区共137种植物,隶属于25科80属;生活型以草本为主,占总植物种数的67.88％;水分生态类型以旱生植物为主,占总数的76.64％.(2)依据《中国植被》将乌拉特荒漠植被类型划...     

The use of understory species as indicators of landform ecosystem type in heavily disturbed forest: an evaluation in the Haut-Saint-Laurent,Quebec

An ecological study of the Municipalité Régionale de Comté (MRC) du Haut-Saint-Laurent area, a highly disturbed landscape located south-west of Montréal (Québec), was carried out. The aim of this study was to establish links between indicator species of ecosystems and geomorphological features in a heavily disturbed background. Analysis to obtain the ecological groups are based on the links of herbaceous plants and shrubs. This approach is defined as a sociological one where grouping is based only on the species' affinity. In order to obtain ecological groups, similarity measures using the chi-square coefficient were calculated on the relative cover values of the 150 retained species from 452 plots. An intermediate linkage cluster analysis was then performed on the similarity matrix thus created. By this procedure, 56 ecological groups were obtained. These groups were then characterized according to abiotic variables, especially the geomorphological data, by the use of binary discriminant analysis. Results indicate that 39 of these 56 groups were significantly associated specifically with one of 10 morphogenic features, while 13 of these 56 groups were associated with 2 or 3 features. The ecological groups which were associated with one specific geomorphological process showed a strong link to one texture and one specific drainage class. On the other hand, the groups which were associated with several features were linked with one drainage class, usually imperfect, and a certain topographic situation. However, ecological groups showing a strong association to more than one feature can be of cartographic use, provided soil texture is analysed to determine the origin of the deposit. Finally, the type of deposit becomes non determinant on vegetation where drainage and topographic variables indicate poorly or very poorly drained sites. Non-significant groups should be used as indicators of drainage and topographical conditions but not as indicators of geomorphological deposits. The ecological groups not associated with morphogenic features demonstrated mostly a heliophilic character. Thus, the ubiquitous character of ecological groups is not exclusive to species taking advantage of disturbances.