Classification and phytogeographical differentiation of oriental beech forests in Turkey and Bulgaria

Floristic differentiation of the oriental beech (Fagus orientalis Lipsky) forests in Turkey and Bulgaria was investigated and the role of geographical and topographical factors in this differentiation was assessed. After geographical and ecological stratification of the available 922 relevés, 288 remained. Classification, by applying cluster analysis, resulted in seven vegetation units defined by species composition which represent the geographical and ecological variation of Fagus orientalis forests. DCA ordination was applied to these units by passively projecting their chorological structure, as supplementary variables. For more detailed interpretation of vegetation types with similar geographic distribution patterns, PCA was applied by passively projecting the chorological elements, life-forms and topographical factors as supplementary variables. Seven vegetation units representing the geographical and ecological variety of Fagus orientalis forests were described. Four vegetation units represent the core area of Fagus orientalis distribution on the western and middle coast of the Black Sea region (Euxine region); the remaining three types represent the distribution in the eastern Black Sea region (Colchic region), the distribution in western and southern Anatolia under the influence of the Mediterranean climate and the distribution in the transitional zone from the Euxine region to the continental parts of Inner Anatolia, respectively. The four vegetation types in Euxine region reflect the decreasing effect of Black Sea towards Inner Anatolia, as well as altitudinal differences, except the forest type representing forests on calcareous sites. The other three vegetation units represent ravine, lowland to montane and altimontane forests in Euxine region. Fagus orientalis forests could be distinguished by their floristic composition, their chorological elements and life-forms spectra, which reflect a geographical and ecological gradients.     

Classification and gradient analysis of the beech forest vegetation of the southern Rodopi (northeast Greece)

Pure and mixed beech forest vegetation of the southern Rodopi range (northeast Greece) was studied using 614 relevés and multivariate analyses (TWINSPAN and DCA). Classification of the relevés resulted in 12 vegetation units, 8 of which were ranked as associations or communities and the rest as subcommunities and variants. DCA diagrams of relevés and taxa indicated that floristic differentiation was attributed mainly to factors such as altitude (affecting temperature and humidity), soil nutrient content and substrate type (affecting physical and chemical soil properties). Differential taxa of vegetation units were chosen based on their phi coefficient values, which were calculated from three different percentage synoptic tables that corresponded to three ranks (ecological groups, associations and communities, and subcommunities and variants) of floristic differentiation. The calculation of phi coefficient on the basis of relative constancy of taxa helps to overcome the problem of the dependence of fidelity values on the number of relevés per vegetation unit and to facilitate the better investigation of the floristic differentiation even of rare vegetation units represented by a small number of relevés. Furthermore, the calculation of fidelity values for different hierarchical levels enables a more detailed and thorough investigation of the floristic differentiation of the vegetation units.     

A phytosociological classification of Swiss mire vegetation

The mapping and monitoring of Swiss mires has so far relied on a classification system based on expert judgement, which was not supported by a quantitative vegetation analysis and which did not include all wetland vegetation types described in the country. Based on a spatially representative sample of 17,608 relevés from 112 Swiss mires, we address the following questions: (1) How abundant are wetland vegetation types (phytosociological alliances) in Swiss mires? (2) How are they distributed across the country––is there a regional pattern? (3) How clearly are they separated from each other? (4) How clear and reliable is their ecological interpretation? Using published wetland vegetation relevés and lists of diagnostic species for phytosociological units (associations and alliances) established by experts, we developed a numerical method for assigning relevés to units through the calculation of similarity indices. We applied this method to our sample of 17,608 relevés and estimated the total area covered by each vegetation type in Switzerland. We found that vegetation types not included in previous mapping were either rare in Switzerland (partly due to mire drainage) or poorly distinguished from other vegetation units. In an ordination, the Swiss mire vegetation formed a triangular gradient system with the Sphagnion medii, the Caricion davallianae and the Phragmition australis as extreme types. Phytosociological alliances were clearly separated in a subset of 2,265 relevés, which had a strong similarity to one particular association, but poorly separated across all relevés, of which many could not be unequivocally assigned to one association. However, ecological gradients were reflected equally well by the vegetation types in either case. Overall, phytosociological alliances distinguished until now proved suitable schemes to describe and interpret vegetation gradients. Nevertheless, we see the urgent need to establish a data base of Swiss wetland relevés for a more reliable definition of some vegetation units.     

Relating variation in the understorey of beech forests to ecological factors

A data set of beech (Fagus sylvatica) forests in the Basque Country (Northern Spain), including biotic (floristic relevés) and environmental data (pH, organic matter, slope, altitude, rock cover), is analyzed in order to describe the relationships between understorey composition and environmental parameters. An ordination technique (DCA) is used to display the floristic gradients, and the interpretation of the floristic space in environmental terms is carried out by a spatial analysis technique (kriging). The composition of the beech forest understorey responds to a complex environmental gradient in the study area. Forests growing on acid substrata differ markedly from those growing on soils with higher pH, as the sharp transition between the pH 5 and 6 isolines reflects. When pH values exceed 6, organic matter content becomes the most important factor explaining the vegetation pattern and the rate of change is greater as organic matter content tends to change at a smaller scale than sample size and, as a consequence many transitional forms are found.     

Fagus sylvatica forest vegetation in Greece: Syntaxonomy and gradient analysis

Abstract. This is the first comprehensive study on Fagus sylvatica s.l. forest communities in Greece. It is based on the multivariate analysis of more than 1100 relevés throughout the distribution area of Fagus in Greece, 60 % of which have been sampled within the last 15 years. The data were compiled from all relevant literature and from unpublished field studies. Prior to data analysis, taxonomic and floristic inaccuracies in older literature have been corrected, and some taxa aggregated. Status and distribution of Fagus in Greece, as well as historical and silvicultural aspects, are outlined. Classification resulted in 16 vegetation types defined by species composition, of which 10 units are ranked as association (of which two were described as new) or community, with six subcommunities included. Synonyms from the literature are given to all types. The floristic structure of the data set is displayed by a synoptic table and by DCA ordination. Community differentiation follows a complex edaphic‐climatic‐phytogeographic pattern. Apart from Fagus sylvatica ssp. orientalis forests of warm and dry habitats and low to medium altitudes which are related to deciduous Quercus forests, four Fagion community groups are distinguished which represent different habitat types: (1) cool, humid, mesotrophic; (2) cool, acidic; (3) high altitude, calcareous; (4) medium altitude, moderately warm and dry. The communities may be assigned to three regional suballiances, viz. (a) Doronico orientalis‐Fagenion at medium altitudes of North‐Central and East‐Central Greece; (b) Doronico columnae‐Fagenion in the far north and at high altitudes southward to East‐Central Greece; (c) Geranio striati‐Fagenion in the Northwest. Various types of thermophilous beech forest are assigned to (a) and (c), acidic forest to (b), and mesic Fagus forest to (b) and (c).     

Environmental conditions in relation to variability of deciduous forest vegetation — a study from volcanic mountain in central Slovakia

The deciduous forests represent dominant natural vegetation of Central European landscape and an important functional component for maintenance of biological diversity. However, their syntaxonomy and ecological gradients still remain unclear. The numerical classification was conducted to determine the main units of forest vegetation, while ordination techniques were used to explain the structure of vegetation-environmental data matrix consisting of 110 forest stands in the Štiavnické vrchy Mts (central Slovakia). Ten vegetation types within the phytosociological classes of deciduous forests Quercetea robori-petraeae and Querco-Fagetea were distinguished. The major environmental driver responsible for variation in forest species composition was interpreted as a response to soil moisture which also accounted for a large part of species variability (3.74%). Soil nutrient/acidity complex expressed by pH, Ca and Al concentration was also an important source of vegetation variability. Relevance of soil conditions in relation to plant survival and community distribution was discussed. Along the soil moisture gradient, vegetation types were arranged from the subxerophilous oak forests through the mesophilous beech and ravine forests to the hygrophilous alder ash vegetation.     

Spontanvegetation Nordgriechischer Bergdörfer

The synanthropic vegetation in seven villages of Northern Greece (N Pindhos and Olympus massif)—situated either in theQuercion confertae or in theFagetalia zone—is analyzed on the basis of about 100 phytosociological relevés. The most important vascular plant species of ruderal sites have also been mapped floristically. Nineteen plant communities are discernible, some of which are mentioned for the first time here. Nevertheless, the author refrains from hastily describing new associations, unless a more detailed phytosociological data basis on ruderal vegetation in the Southern Balkans is available. A table refers to differences and similarities between the recognized plant communities in Greek villages and those which correspond to them in Central Europe. Non-industrial methods of agriculture and animal husbandry are among the most important conditions for the remarkable rich vegetation in Greek mountain villages.     

An ecological approach to the investigation of a beech forest in Vestfold, SE Norway

The vegetation in a beech forest, Fritzøehusparken, is analysed using one hundred sample plots, each 25 m², distributed by a restricted random procedure. Percentage cover and frequency in subplots are used for quantification of species amounts, and their relative performance are evaluated. Advantages of choosing frequency in subplots are discussed. Thirteen environmental variables are measured from each of the sample plots. The vegetation is divided into four topographical/ecological types. This classification served as a reference in the further treatment. Ecological gradients corresponding to the most important vegetational gradients in the beech forest are identified by means of DCA ordination followed by statistical interpretation. Two main complex gradients were recognized; (1) the gradient in nutrient conditions, and (2), the gradient inlitter-wind conditions. The advantages of using DCA and statistical interpretation with integration of ecological measurements are emphasized.     

Current knowledge and phytosociological data on the high-altitude vegetation in the Western Carpathians — a review

Presented survey summarizes the results of the studies published predominantly after 2000, dealing with the plant communities around and above the timberline in (montane) subalpine to alpine (subnival) belt of the Western Carpathians. All of these communities underwent a critical syntaxonomical and nomenclatorical revision, hence the demonstrated overview of high-mountain vegetation of Western Carpathians (mostly from Slovakia, less from Poland border areas) represent the current state of knowledge. The high-altitude vegetation database, which is the part of Slovak National Vegetation Database, SNVD (), incorporated 8,160 published relevés on 15 May 2007 (of the total of 30,469 published relevés in the SNVD). Concerning the unpublished relevés, the individual authors have provided more than 18,400 of them to be stored in SNVD; 2,301 of all unpublished relevés could be assigned to high-altitude vegetation. Mountain and alpine vegetation is in SNVD presented by 15 classes; the most frequent class is Mulgedio-Aconitetea. With its quantity and also the quality of relevés, the high-altitude database, as well as the whole SNVD, represents the unique database within Slovakia, which provides information not only about the locality, floristic composition and variability of individual vegetation types, but also about several environmental variables such as inclination, aspect, geology or soil type, characteristic for individual relevés. Together with other Central European databases, SNVD takes up the leading position in Europe.     

Native woody vegetation in central Argentina: Classification of Chaco and Espinal forests

Question

What are the composition and spatial patterns of native woody plant communities in the southern Great Chaco and Espinal?

Location

Córdoba Province, central Argentina, an area of ca. 161,000 km².

Methods

We collected 351 geo‐referenced relevés representative of the geographic, topographic and ecological variation of the Chaco and Espinal woody vegetation in central Argentina. The relevés were classified into vegetation types using the hierarchical ISOPAM method. Forest and shrubland types were described on the basis of diagnostic species occurrences and their distribution in relation to environmental factors. A map of the actual vegetation derived from remote‐sensed images (Landsat) and field data was used to describe the current distribution and abundance of the different vegetation types.

Results

The classification of the 351 plots × 837 species matrix revealed two major clusters comprising seven woody vegetation types corresponding to Chaco lowland and mountain forests and shrublands, Espinal forests and edaphic vegetation. The most important gradients in woody vegetation types are related to elevation, temperature and rainfall variables.

Conclusions

Subtropical seasonally dry woody plant communities from the southern extreme of the Great Chaco and Espinal forests were described for the first time based on complete floristic data. Our results show that lowland Chaco native forests, as well as replacement communities, are still present in its southern distribution range and are well distinguishable from other vegetation types such as the Espinal and mountain forests. Overall, extensive Espinal forests have almost disappeared while Chaco vegetation is highly fragmented and degraded.

     

Understorey vegetation development in North Finnish Picea forests after disturbance: re‐analysis of Sirén's data

Abstract. Sirén (1955) studied understorey species composition, tree stand properties and humus‐layer thickness in 64 unlogged forest stands on topographically and pedologically comparable sites. The stands were of even age (6 – 300 yr), stocked with the first or second tree generation after wildfire. The view of Sirén and several authors after him, that the vegetation of old‐growth boreal Picea forests is homogeneous on a broad scale, was examined by applying, in parallel, the partial variants of two ordination methods (DCA and PCA) to Sirén's vegetation data. Two main vegetation gradients were found: a major gradient running from recently burnt plots with prominence of pioneer species to plots with stand age > 100 yr, a well stocked tree layer and a thick humus layer, dominance of feather‐mosses and ample occurrence of shade‐tolerant as well as light‐preferring vascular plant species, and a second gradient along which first‐ and second‐generation plots segregate. The more prominent element of Betula trees in first‐ than in second‐generation stands < 100 yr contributed to the latter. A minor third gradient related to humus‐layer thickness was recovered by partial DCA only. The main vegetation gradient reappeared in separate ordinations of data from 47 mature forest stands (> 100 yr), but without being correlated with forest age. Variation among mature‐forest stands in the importance of pioneer species is considered mainly to be brought about by fine‐scale disturbance processes such as tree uprooting. Increasing importance of factors operating on within‐stand scales [development of a varied gap structure and stronger gradients in tree influence (radiation at ground level), soil moisture, soil depth and nutrient availability] with time is also reflected in the second and third mature‐forest ordination axes. Possible implications of the results for conservation of biological diversity and monitoring of changes in boreal forests are discussed.     

Diversity,variability and habitat characteristics of the communities dominated by Sesleria species (Poaceae) in the Western Carpathians

This study provides a view of vegetation types dominated by Sesleria species in the Western Carpathians (Sesleria caerulea, S. heufleriana, S. tatrae, and S. uliginosa). We also took into account characteristics/traits such as plant life forms, autochthonous status, endemism, and ploidy level occurring within each relevé in our data set. Altitude and Ellenberg indicator values derived for each relevé were considered as well. Eight vegetation types/formations/habitats were recognized in a data set of 942 phytosociological relevés: (1) synanthropic vegetation, (2) rock fissures and screes, (3) alpine grasslands and heaths, (4) mesic grasslands and pastures, (5) springs and fens, (6) forests, (7) xerophilous shrubland, and (8) high-mountain scrubs (krummholz). Results corroborated and clearly emphasized that Sesleria caerulea has the widest ecological amplitude of all studied species because the species occurred among all studied vegetation types. Sesleria tatrae was present only in several vegetation types occurring from montane to alpine vegetation belts in the highest mountains. Sesleria heufleriana and S. uliginosa were recorded only in low-altitude areas. The difference between them lies mainly in the dampness of each locality. Sesleria heufleriana was frequently found in xerophilous communities, whereas S. uliginosa preferred humid habitats of springs and fens.     

Vegetation of beech forests in the Rychlebské Mountains,Czech Republic,re-inspected after 60 years with assessment of environmental changes

From 1941–;1944 nearly 30 phytosociological relevés were completed by F. K. Hartmann in the Rychlebské Mountains, a typical mountainous area in northeastern Czech Republic. Of the original plots still covered with adult grown beech (Fagus sylvatica) forest, 22 were resampled in 1998 and 1999. In order to describe the recent vegetation variability of the sites 57 relevés were recorded. Changes in vegetation were estimated using relative changes in species density and ordinations (PCA, RDA). Environmental changes were assessed using Ellenberg indicator values when no direct measurements were available. A decline in species diversity has been documented, particularly, many species occurring frequently in deciduous forests with nutrient and moisture well-supplied soils around neutral have decreased. In contrast, several light-demanding, acid- and soil desiccation-tolerant species have increased. Natural succession, quantified as forest age, contributed slightly to these changes. In Ellenberg indicator values, a decline in F (soil moisture), R (soil calcium) and N (ecosystem productivity), and an increase in L (understorey light) were shown. This is interpreted as the influence of modified forestry management and of airborne pollutants. Intensified logging caused the canopy to open and soil conditions to worsen. The latter is most likely also due to acid leaching of soil cations (Ca, K, Na). This caused a decline in soil productivity, thus the effect of nitrification could not be detected. The original relevés may have differed in size influencing the results. This revised version was published online in August 2006 with corrections to the Cover Date.     

Environmental factors–ecological species group relationships in the Surash lowland‐mountain forests in northern Iran

Identification of the primary factors that influence the ecological distribution of species groups is important to managers of lowland‐mountain forests in northern Iran. The aim of this study was to identify main ecological species groups, describe the site conditions associated with these species groups and the relationships between environmental factors and the distribution of ecological species groups using multi‐variate analysis (Detrended correspondence analysis (DCA) and Canonical correspondence analysis (CCA)). For this purpose, 50 relevés (400 m² each) were sampled using the Braun‐Blanquet method. Vegetation was classified into three ecological species groups using a modified two‐way indicator species analysis (TWINSPAN). In each relevé, environmental factors (topographic and soil variables) were measured and analysed using one‐way ANOVA and Pearson r statistics. Further, species diversity indices were determined for the identified ecological species groups. Our results show that the environmental factors, e.g. elevation, slope, slope aspect, soil texture, pH and organic matter, were the most important factors explaining the distribution of the three ecological species groups in the study area. The diversity of the ecological species groups decreased with elevation. The results provide an ecological basis for forest management and for developing strategies for forest conservation in the study area.     

ORIGINAL ARTICLE: Can Ellenberg's indicator values for Mediterranean plants be used outside their region of definition?

Aim The aims of this study are: (1) to explore the relationships between the Ellenberg indicator values (light, temperature and moisture) recently developed for two Mediterranean regions (Italy and Greece); and (2) to evaluate the possibility of using these values in other Mediterranean areas. Location Southern Greece and the Mediterranean part of Italy. Methods A global matrix containing 966 items of information (161 species × 3 indicator variables × 2 values assigned in each study, one in Italy and one in Greece) was constructed. A test of the accuracy of the values in predicting actual environmental conditions was provided using a detrended correspondence analysis (DCA) on published vegetation relevés from the Mediterranean region. The gamma statistic was used to express relationships of ecological indicator values between the two regions, and pairs of indicator values calculated for each species were compared using Wilcoxon matched pairs tests. Results The results showed that indices developed for Greece and Italy were not similarly correlated to sample scores along DCA axis 1. Species’ indicator values for Italy and for Greece were highly significantly correlated for light and moisture and significantly correlated for temperature, but the correlations were weak (0.20 ≤ gamma ≤ 0.31). Pairwise testing gave significantly different indicator values for the two regions. Discrepancies below or equal to 2 units on 9‐point scales (12 points for moisture) were found for 88%, 70% and 54% of the species respectively for light, temperature and moisture indices. A substantial number of species showed higher discrepancies, from 3 up to 6 units. Main conclusions In the light of the present work, it seems clear that the indicator values developed for Italy and for Greece should not be used outside the region for which they were defined. This constitutes additional evidence that indicator values can be influenced by the identity of potential competitors. It also underlines the need to use standardized methods for calibrating indicator values against measured variables in such a way that indicator systems can serve as general reference systems.     

Complex fine‐scale phylogeographical patterns in a putative refugial region for Fagus sylvatica (Fagaceae)

Broad‐scale plastid (chloroplast) DNA studies of beech (Fagus sylvatica) populations suggest the existence of glacial refugia and introgression zones in south‐eastern Europe. We choose a possible refugium of beech in northern Greece, Mt. Paggeo, which hosts a private plastid haplotype for beech, to conduct a fine‐scale genetic study. We attempt to confirm or reject the hypothesis of the existence of a small‐scale refugium and to gain an understanding of the ecological and topographical factors affecting the spatial distribution of plastid haplotypes in the area. Our results reveal a high haplotype diversity on Mt. Paggeo, but the overall distribution of haplotypes shows no significant correlation with the ecological characteristics of the beech forests. However, the private haplotype is found at high frequencies in beech forests located in or near ravines, having a high spatial overlap with a relict vegetation type occurring in ecological conditions found mainly in ravines. This result emphasizes the importance of topography in the existence of glacial refugia in the wider area. Furthermore, haplotypes originating from two more widespread beech lineages in Greece are found on Mt. Paggeo, indicating a possible mixing of populations originating from a local refugium with populations from remote refugia that possibly migrated into the area after the last glaciation. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 516–528.     

Trends in species diversity and composition of urban vegetation over three decades

Question: What was the change in diversity of urban synantropic vegetation in a medium‐sized Central European city during the period of increasing urbanization (1960s‐1990s)? Location: The city of Plzeň, an industrial centre of the western part of the Czech Republic. Methods: Sampling of various types of synanthropic vegetation, conducted in the 1960s, was repeated by using the same methods in the 1990s. This yielded 959 relevés, of which 623 were made in the 1960s and 336 in the 1990s. The relevés were assigned to the following phytosociological classes: Chenopodietea, Artemisietea vulgaris, Galio‐Urticetea, Agropyretea repentis and Plantaginetea majoris. Total number of vascular plant species, evenness index J, number of alien species (classified into archaeophytes and neophytes), and mean Ellenberg indicator values for light, temperature, continentality, moisture, soil reaction, and nutrients were obtained for each relevé. Results: From 1960s to 1990s, there was a significant decrease of species richness and diversity in synanthropic vegetation. The proportion of archaeophytes decreased in most vegetation types, indicating the contribution of this group of species, often confined to specific rural‐like habitats, to the observed impoverishment of ruderal vegetation. The proportion of neophytes did not change between the two periods. Comparison between 1960s and 1990s indicated a decrease in light, temperature, moisture, soil reaction and nutrient indicator values in some vegetation types. In both periods, Artemisieta, Galio‐Urticetea and Chenopodietea formed a distinct group harbouring more species than Agropyretea and Plantaginetea. Neophytes, i.e. recently introduced species, were most represented in the early successional annual vegetation of Chenopodietea, rather than in perennial vegetation of the other classes. Conclusions: Synanthropic vegetation of Plzeň exhibited a general trend of decrease in species diversity.     

Gradient analysis of dry grassland vegetation in Denmark

Abstract. We present a gradient analysis of 620 vegetation samples covering most of the floristic and environmental variation in semi‐natural grassland vegetation on well‐drained soils in Denmark. Vegetation was sampled using frequency in subplots. Explanatory variables were surface inclination, aspect, pH, geographical co‐ordinates together with indications of soil type. Detrended Correspondence Analysis revealed four floristic gradients that could be interpreted in ecological terms by measured variables supplemented with site calibrations based on weighted averaging of Ellenberg's indicator values. All four axes were interpreted using rank correlation statistics, and linear and non‐linear multiple regression of sample scores on explanatory variables. The first gradient was from dry calcareous to humid acidic grasslands; the second reflected an underlying gradient in fertility; the third reflected regional differentiation and the fourth was associated with variation in intensity of competition as indicated by association with calibrated Grime‐CSR values for the plots. We applied subset ordination to the data as a supplement to traditional permutation and correlation statistics to assess the consistency of ordination results. DCA axes 1 and 2 were consistent in space and time. This gradient analysis is discussed in a context of plant strategy theory and species diversity models. Ecocline patterns lend support to the view that grazing not only favours the ruderal strategy but also the stress‐tolerant strategy. The low rank of competition as an explanatory variable for the floristical gradients supports the notion that competitive effects play a subordinate role for species composition compared to microclimate and soil conditions in infertile semi‐natural grasslands.     

Spatial and altitudinal bioclimatic zones of the Italian peninsula identified from a beech (Fagus sylvatica L.) tree-ring network

A network of 24 beech (Fagus sylvatica L.) tree-ring chronologies has been developed for the Italian peninsula. Principal component and cluster analyses were used to identify geographical and altitudinal patterns of tree growth. Correlations and response functions were then applied to the main modes of tree-ring variability to uncover climatic signals. In a landscape occupied by humans for millennia, this approach provided a detailed quantitative ecological characterization of forest types. Altitude was significantly correlated with dendrochronological parameters. The Alps and northern Apennines could be distinguished from the central-southern Apennines. In central Italy, we recognized three different vegetation belts occupied by beech forests, from low- to high-elevation sites. Summer drought impacted beech growth with different intensity at different elevations, depending on the onset and duration of the growing season. Moreover, low-elevation beech forests showed a distinct late spring climate signal, which was opposite to that of high-elevation sites. The coherent geographical and ecological patterns of tree-ring variability suggest that dendrochronological networks help define bioclimatic zones and forest types.