The coastal plant communities of Juniperus macrocarpa in the Mediterranean region

Juniperus macrocarpa is a threatened taxon growing on coastal areas of the Mediterranean region. A remarkable part of its communities are included in Juniperion turbinatae, considered as priority habitats for conservation in the Habitats Directive 92/43 EEC. We have summarized the current status of this type of vegetation, including the described associations of this alliance in order to analyse the variability of the syntaxa, based on its floristic composition and geographic distribution. The available relevés were arranged in a synthetic table and subjected to a detendred correspondence analysis. Two new suballiances (Juniperenion turbinatae and Asparago orientalis-Juniperenion macrocarpae) have been proposed. A typological classification of these communities with ecological and biogeographical diagnoses is given.     

Typology and ecology of Californian serpentine annual grasslands

Abstract. A first classification for serpentine annual grasslands distributed throughout northern and central California is proposed. This study has followed the Braun‐Blanquet phyto‐sociological system based on floristical, biogeographical and bioclimatic features of the sampled areas. Numerical analyses of classification and ordination were applied to the floristic relevés. Minimum Variance Clustering grouped relevés into basic classification units that allowed us to define low‐hierarchical syntaxonomical units (associations) and ‘communities’. A Principal Coordinate Analysis was used to extract those ecological parameters related to the axes that separate those classification units from the previous dendrogram. The results showed that differences in species composition was mainly due to a continentality gradient and the shady effect of an overstory vegetation. On the basis of both analyses we propose a first syntaxonomic scheme on ultramafic (mainly serpentine) annual plant communities of the biogeographical Californian Region that comprises four associations, two subassociations and some provisional communities.     

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.     

Syntaxonomic study of vegetation in Velká Kotlina cirque,the Sudeten Mountains

A species-rich flora consisting of about 350 species of vascular plants and 200 of bryophytes has developed in the Velká Kotlina cirque, as a result of biotope diversity and uninterrupted Postglacial evolution. A longlasting interaction of the species pool with a variety of habitats covering about 1 km² has created numerous species-saturated communities whose structure reffects both biogeographical characters of the whole Sudeten Mountains, and local peculiarities in soil, microclimate and hydrology. In a set of 400 vegetation relevés altogether 29 associations, 15 alliances, 10 orders and 10 classes have been identified. Each of the 16 newly described associations and also 14 subassociations, is characterized by the appropriate original diagnosis and full enumeration of the nomenclatural type.     

Perennial nitrophilous vegetation of the northern Iberian Peninsula

Abstract. The syntaxonomy of the perennial nitrophilous vegetation assigned to the Artemisietea vulgaris of the northern part of the Iberian Peninsula (Basque Country and surrounding areas) was revised. The study area is of biogeographic importance due to its transitional character - here, the ruderal vegetation of the Mediterranean and that of temperate Europe meet. Numerical ordination of the communities was performed in order to reveal systematic relations between the syntaxa. Two subclasses, Artemisienea vulgaris and Onopordenea, encompassing five orders, Convolvuletalia, Galio-Alliarietalia, Artemisietalia, Onopordetalia, Carthametalia lanati, and seven alliances with 12 associations and two rankless communities were distinguished.     

Marshland vegetation of the class <Emphasis Type="Italic">Phagmito-Magnocaricetea</Emphasis> in Croatia

The marshland vegetation of the class Phragmito-Magnocaricetea in Croatia is presented in a single place for the first time. All the available relevés from the literature have been assembled and supplemented with the results of field research. Thirty-three communities have been established, shown in a synoptic table drawn up on the basis of 486 relevés. The communities are understood according to the traditional syntaxonomic system based on the dominant or diagnostic species. For the purposes of comparison, the marshland vegetation is classified using numerical methods as well. The results obtained show that most clusters correspond to specific associations, but do not confirm the division into vegetation alliances and orders. The marshland communities with the most relevés in the dataset, and that therefore can be considered the most widespread in Croatia, are: Phragmitetum australis, Caricetum gracilis, and Galio palustris-Caricetum ripariae. The marshland vegetation is also analysed from the standpoint of nature conservation. In the dataset studied, 59 taxa from the Red Book of Vascular Flora of Croatia are identified as threatened, the 15 most endangered marshland communities are separated, and 10 neophytes and one neophyte association are registered. The diversity of marshland vegetation, and of the associated plant species, is considerably higher in inland Croatia than along the Adriatic coast, which is probably a result of the geological bedrock, climate and, in some places, halophile conditions.     

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.     

Syntaxonomic revision of chasmophytic vegetation of the Centaureo cuspidatae-Portenschlagiellion ramosissimae (Southeastern Adriatic)

Abstract

The Centaureo-Portenschlagiellion describes the cliff vegetation of the Southeastern Adriatic. This habitat type harbours many endemic taxa and has a high value for biodiversity conservation. Notwithstanding its importance, knowledge of the syntaxonomy of this alliance is still poor. This article aims at revising the synchorological, coenological and floristic relationships of the associations of the Centaureo-Portenschlagiellion. The revision is based on a data set of 103 relevés of Mediterranean xerothermic cliffs from Croatia, Bosnia i Herzegovina and Montenegro. The relevés were clustered by using the Flexible beta method. An indicator species analysis was used to identify the diagnostic taxa of the main clusters of relevés and non-metric multidimensional scaling ordination was undertaken to visualize the floristic relationships among them. Results revealed that only seven associations belong to the Centaureo-Portenschlagiellion, whereas the others already described in phytosociological literature were invalidly described or should be treated as syntaxonomic synonyms of the previous ones. Two associations (Inulo-Centaureetum cuspidatae and Portenschlagiello-Campanuletum portenschlagianae) were reduced to the rank of subassociations of the Moltkio-Inuletum verbascifoliae. Two other subassociations were described for the first time. Data provided with this revision may be considered as essential base-line information that should aid in evaluating the state of this vegetation type in the future.     

The Quercus petraea-dominated communities in Italy: Floristic,coenological and chorological diversity in an European perspective

In Italy, woods dominated by Quercus petraea are well documented within local and regional phytosociological studies but a critical revision of their principal ecological-floristic components based on a comprehensive Italian data set was missing. We gathered 209 published and unpublished Italian phytosociological relevés, where Q. petraea was dominant, that were investigated by means of multivariate analysis. The ecological requirements of the resulting groups were indirectly calculated by means of Ellenberg indicator value, and a chorological analysis was performed. The fidelity coefficient (phi) for the diagnostic species of each group was calculated. According to our analysis, five different types of Q. petraea woods were found to be present in Italy. Each group was characterized by means of its floristic, ecological and chorological components. These resulting five groups were further compared with similar Q. petraea-dominated woods recorded in other European locations, as to the floristic and chorological components. We collected 57 synoptic tables of Q. petraea communities coming from all over Europe. This data set, together with the Italian relevés, was submitted to exploratory multivariate analysis using also the chorological information. According to these analyses, the Italian woods dominated by Q. petraea can be subdivided in two main clusters: the communities belonging to It-1 group (Alps) fell within the central European communities, distinguished by the predominance of large distribution and European chorotypes. All the other Italian groups of relevés resulted to be positioned in the cluster which includes central southern, central eastern and eastern European Q. petraea communities. From the syntaxonomical point of view, the results of this analysis allow to attribute the Italian Q. petraea woods to seven alliances of three different orders. The ecological similarities between Erythronio-Quercion petraeae and Erythronio-Carpinion betuli are highlighted and the distribution of Erythronio-Quercion petraeae is limited to northern Apennines, in particular, to slopes facing the Po Valley.     

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.     

Marshland vegetation of the class <Emphasis Type="Italic">Phragmito-Magnocaricetea</Emphasis> in northwest Croatia (Krapina river valley)

Marshland vegetation of the class Phragmito-Magnocaricetea in the Krapina river valley was investigated during 2006 and 2007, and some sporadic investigations were made earlier. Phytosociological studies were carried out in accordance with the standard Braun-Blanquet methodology. As a result of the field work, and a small amount of data from the literature, 120 relevés were collected and 18 communities were established. For the purposes of comparison, the relevés were also classified using numerical methods. The clusters obtained mostly correspond to specific associations, but do not confirm the division into traditional vegetation alliances and orders. In the analysis of the ecological factors it is established that separation of the relevés is influenced by nutrient content, soil reaction, soil moisture, depth of water, and type of management. Analysis of the plant life forms shows, in all marshland communities, a prevalence of hemicryptophytes, geophytes and hydrophytes. The most widespread marshland communities of the investigated area are: Phalaridetum arundinaceae, Phragmitetum australis and Galio palustris-Caricetum ripariae. Furthermore, Carex randalpina community is recorded for the first time in Croatia. The most threatened marshland communities could be considered to be: Carex randalpina community, Caricetum vesicariae, Leersietum oryzoidis and Oenantho-Rorippetum. They are selected because of their very small surfaces in the investigated area and the small number of known localities within the territory of Croatia. The most invasive alien plant species in the Krapina river valley is Solidago gigantea. It spreads in potential habitats of marshland vegetation, and it is recorded in the species composition of many marshland communities. For the preservation of marshland vegetation, and especially threatened types, it is necessary to maintain the water regime of the habitats, to not remove natural plant cover due to spreading of neophytes, and to provide occasional mowing and burning.     

Coastal salt-marshes plant communities of the Salicornietea fruticosae class in Apulia (Italy)

An overview of the salt-marsh herbland and scrub vegetation belonging to the class Salicornietea fruticosae Br.-Bl. et Tx. ex A. Bolòs y Vayreda 1950 in Apulia is presented. Data available from literature have been supplemented with original relevés performed in different locations of the Apulia region. On the basis of a total of 297 relevés, fifteen communities have been defined, according to the traditional phytosociological system based on dominant and/or diagnostic taxa. For comparison purposes, the salt-marsh vegetation has been classified using numerical methods. The results obtained show that most of the clusters correspond to specific associations, and confirm the division into vegetation alliances and orders. Numerical analysis also allowed us to assign the proper allocation of some associations and plant communities drawn from literature. Five alliances, with plant communities characterized by specific ecological features, have been discriminated: Sarcocornion alpini and Arthrocnemion glauci (lower marshes), Salicornion fruticosae (middle marshes), Inulion crithmoidis and Suaedion brevofoliae (upper marshes). In addition, during the field work, a population of Halocnemum strobilaceum (Arthrocnemo-Halocnemetum strobilacei), new record for the Apulia region, has been found.     

Revision of the central Mediterranean xerothermic cliff vegetation

Questions

What are the syntaxonomic and synchorological patterns of the xerothermic chasmophytic vegetation in the central part of the Mediterranean Basin? What are the diagnostic species of the high‐rank syntaxa of Asplenietalia glandulosi, Onosmetalia frutescentis and Centaureo dalmaticae‐Campanuletalia pyramidalis?

Location

Mediterranean coastal and subcoastal areas of southern France, Italy, Malta, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Albania and of mainland Greece.

Methods

The data set of 1,261 published relevés was analysed using hierarchical clustering (Flexible Beta method), involving a series of data transformations. Indicator species analysis was used to select the best dendrogram solution and identify diagnostic taxa of the main clusters. The dendrogram was interpreted from a syntaxonomic point of view, using nomenclatural type relevés as a basis. The NMDS ordination was performed in order to visualize the floristic relationships among associations and high‐rank syntaxa. MRPP was used to test for differences among alliances.

Results

The classification revealed four main clusters of relevés representing the chasmophytic vegetation of southern France, Sardinia and the northwestern part of Italy (Asplenienalia glandulosi/Asplenietalia glandulosi), the southwestern part of Italy and Malta (Tinguarrenalia siculae/Asplenietalia glandulosi), the Adriatic Basin area (Centaureo dalmaticae‐Campanuletalia pyramidalis) and the southern Balkans (Onosmetalia frutescentis). The NMDS ordination confirmed the overall pattern, while MRPP showed significant differences among the alliances of the above‐mentioned orders and suborders. The lists of diagnostic taxa of the high‐rank syntaxa were revised according to a supra‐national perspective.

Conclusions

The new syntaxonomic scheme provides a comprehensive overview of the chasmophytic vegetation of the central part of the Mediterranean Basin. This scheme mostly matches the recently published EuroVegChecklist, but also exhibits important novelties concerning the syntaxonomic position of some alliances (Dianthion rupicolae, Centaureion pentadactyli, Arenarion bertolonii and Caro‐Aurinion), and the floristic and chorological relationships among high‐rank syntaxa, with new revised sets of diagnostic taxa. This revision might be useful for further small‐scale phytosociological studies.

     

Numerical reproduction of traditional classifications and automatic vegetation identification

Questions: Is it possible to develop an expert system to provide reliable automatic identifications of plant communities at the precision level of phytosociological associations? How can unreliable expert‐based knowledge be discarded before applying supervised classification methods? Material: We used 3677 relevés from Catalonia (Spain), belonging to eight orders of terrestrial vegetation. These relevés were classified by experts into 222 low‐level units (associations or sub‐associations). Methods: We reproduced low‐level, expert‐defined vegetation units as independent fuzzy clusters using the Possibilistic C‐means algorithm. Those relevés detected as transitional between vegetation types were excluded in order to maximize the number of units numerically reproduced. Cluster centroids were then considered static and used to perform supervised classifications of vegetation data. Finally, we evaluated the classifier's ability to correctly identify the unit of both typical (i.e. training) and transitional relevés. Results: Only 166 out of 222 (75%) of the original units could be numerically reproduced. Almost all the unrecognized units were sub‐associations. Among the original relevés, 61% were deemed transitional or untypical. Typical relevés were correctly identified 95% of the time, while the efficiency of the classifier for transitional data was only 64%. However, if the second classifier's choice was also considered, the rate of correct classification for transitional relevés was 80%. Conclusions: Our approach stresses the transitional nature of relevé data obtained from vegetation databases. Relevé selection is justified in order to adequately represent the vegetation concepts associated with expert‐defined units.     

The Pinus halepensis Mill. forests in the central-eastern European Mediterranean basin

The Pinus halepensis Mill. forest vegetation of the central-eastern European Mediterranean basin (France, Italy, Croatia, Albania, Greece) is described here. This study was carried out considering published and unpublished phytosociological data, with the organisation of a systematic classification (syntaxonomic scheme) of the order Pinetalia halepensis according to the principal floristic variations, at multiple spatial scales and according to the physiognomic–structural, floristic, ecological and biogeographical characteristics. Five alliances and 25 associations are recognised.     

Classification of peatland vegetation in Atlantic Canada

Abstract. The peatlands of Atlantic Canada are classified in four plant alliances, consisting of 10 plant associations. The four plant alliances comprise the dry bog communities (Kalmio-Cladonion Wells 1981), wet bog communities (Scirpo-Sphagnion Wells 1981), hummock and ridge communities of slope and string fens (Betulo-Sphagnion Wells all. nov.), and poor, intermediate and rich fen plant communities (Scirpo-Myricion Wells 1981). Distribution maps are presented for relevés in each of the 10 associations. Based on species distributions, floristic regions are defined for peatlands in Atlantic Canada. Nutritional characteristics are also described for each plant association. pH and total soil concentrations of calcium, nitrogen and iron proved reliable in separating bog from fen. A boundary between ombrotrophic peatlands and minerotrophic peatlands is suggested, based on a soil pH of 4.0, total soil concentrations of 3.0 mg g^?1 Ca, 4.0 mg g^?1 Fe, 13.0 mg g^?1 N and a Ca/Mg ratio of 2.5. Comparisons between the syntaxa for peatlands in Atlantic Canada and those in Europe are discussed for higher taxa. The possibility of establishing a new order (Chamaedaphno-Scirpetalia Wells ord. nov.) for peatlands in Atlantic Canada is also discussed.     

Syntaxonomic analysis of theAndropogon-rich grasslands (Hyparrhenietalia hirtae) in the western Mediterranean region

Using the Braun-Blanquet approach, a syntaxonomical revision of the orderHyparrhenietalia hirtae in the western Mediterranean region was made. Various syntaxa were studied with relevés from the Iberian Peninsula, southern France, Sardinia, Sicily and adjacent islands, Balearic Islands, Canary Islands and Morocco. One alliance (Hyparrhenion hirtae), 8 associations (one of them new:Lotononido lupinifoliae-Hyparrhenietum sinaicae) and several subassociations and variants were distinguished. A complete classification of theHyparrhenietalia hirtae in the studied area with ecological and biogeographical diagnoses is given.     

Syntaxonomy and Synecology of <Emphasis Type="Italic">Quercus coccifera</Emphasis> Mediterranean Shrublands in Greece

Quercus coccifera (kermes oak) is the most common species of the Mediterranean maquis with a wide distribution across the Mediterranean Basin. This paper presents a syntaxonomic overview of the Q. coccifera plant communities in the Mediterranean zone of Greece (Quercetea ilicis) based on the classification of 221 relevés from 34 (17 continental and 17 insular) mountainous areas throughout Greece. Two associations and eight sub-associations are described and presented in a synoptic constancy table. Querco cocciferae–Pistacietum lentisci is the most widespread, is found in the entire continental Greece and most islands, and is further subdivided into five sub-associations reflecting primarily local peculiarities in the disturbance regime and the influence of local floristic elements. Rhamno lycioidis–Cocciferetum (Rivas Goday & Rivas-Martínez 1954), on the other hand, is geographically confined on the island of Crete and is further subdivided into three sub-associations, reflecting differences in the annual precipitation, and they are characterized by the presence of many phryganic and grazing-resistant species. Climate and the anthropogenic pressure have been identified to be the most important factors determining the structure and the floristic composition of Q. coccifera Mediterranean shrublands of Greece.     

Relationships between syntaxonomy ofThero-Salicornietea and taxonomy of the generaSalicornia andSuaeda in the Iberian Peninsula

This paper deals with the syntaxonomy of the classThero-Salicornietea in the Iberian Peninsula, falling particularly upon the significance that taxonomy of the generaSalicornia andSuaeda has on it. Three alliances were differentiated, two Atlantic and one Mediterranean. The Atlantic ones wereSalicornion dolichostachyo-fragilis, with four associations grouping slikke communities with tetraploid glasswort (Salicornia) species, andSalicornion europaeo-ramosissimae, with three associations of schorre with generally diploid glasswort species. The Mediterranean allianceSalicornion patulae had six associations distributed both in coastal (southern and eastern coasts) and inland salt marshes. A complete syntaxonomy of the class, maps of the distribution of its associations and tables summarizing their floristic composition are also provided.