Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft, Band 30 (2010)
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- Festuco-Brometea (2)
- Molinio-Arrhenatheretea (2)
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A systematic survey of grassland communities in central Slovakian sub-montane and montane regions (including the Kremnické vrchy Mts., Starohorské vrchy Mts., Veľká Fatra Mts., and Zvolenská kotlina Basin) was performed between 1996 and 2007. The main aim was to identify main environmental gradients in the studied vegetation and to estimate the most important individual variables responsible for the variation of their species composition. Along with the floristic composition, the environmental variables were either recorded in the field (altitude, slope, aspect), calculated (solar radiation, climatic data, and phytochorological affinity), or derived from available maps or GIS digital data layers (type of bedrock, soil parameters). These environmental variables were used as supplementary in the detrended correspondence analysis (DCA) or explanatory in the canonical correspondence analysis (CCA). The affiliation of individual phytosociological relevés to associations was estimated by an electronic expert system for Slovak grassland communities. Altogether, 15 xero-, sub-xero- and mesophilous grassland associations were distinguished. Wet and fen meadows were analysed at the level of alliances. Unconstrained ordination revealed moisture and nutrient gradients as most important for the data set. By means of constrained ordination, the variability of the studied vegetation could be explained by a set of geological, topographic, phytochorological and derived climatic variables, although the percentage of explained variance was rather low and did not exceed 12% for all significant factors combined. Among individual variables, the geological bedrock type, climatic water balance, solar radiation, and slope played the most important role in determining the distribution and variability of individual grassland communities. Affinity to phytochorions determined according to local air temperature gradients was also significant. Soil properties played only a subordinate role in our analyses. The analysis of a more homogeneous subset of the data without wetland relevés gave similar results as the analysis of the complete data set. The differences in results of constrained and unconstrained ordinations are discussed together with the potential reasons for extremely high proportion of unexplained variance revealed by the variation partitioning methods.
The main aim of this paper was to test the national electronic expert system for grassland classification in Slovakia as a tool for grassland classification on a regional data set from an area with high vegetation diversity. The study region comprised five orographic units located in central Slovakia (Starohorské vrchy Mts., Kremnické vrchy Mts., Veľká Fatra Mts., Nízke Tatry Mts. and Zvolenská kotlina Basin). The data set included 411 phytosociological relevés of all grassland types (xero-, subxero- and mesophilous grasslands as well as wet and fen meadows), recorded by the authors between 1980 and 2007. The relevés were classified to associations by the expert system formulated for the Slovak grassland vegetation either according to association definitions or (in case of relevés not matching any association definition) according to the Frequency-Positive Fidelity Index (FPFI). Wetland relevés were classified according to results of a cluster analysis. Diagnostic species from the regional data were compared to diagnostic species derived at the national level from the data including all vegetation units in Slovakia. According to the results, 49% of the relevés classified by the expert system were matched by the association definitions. Xerophilous grasslands were classified within three alliances of the class Festuco- Brometea: Festucion valesiacae, Bromo pannonici-Festucion pallentis and Diantho lumnitzeri-Seslerion. The occurrence of these communities in the region is rare, restricted to rocky habitats and steep slopes with shallow soil over calcareous bedrock. Sub-xerophilous grasslands were classified within four associations belonging to the two alliances Cirsio-Brachypodion pinnati and Bromion erecti. In the study region, these communities are widely distributed mainly in areas built by calcareous bedrock. Mesophilous grasslands are the most common communities in the study region. They were classified within eight associations belonging to four alliances: Cynosurion cristati, Arrhenatherion elatioris and Polygono bistortae-Trisetion flavescentis (all of them belonging to the class Molinio-Arrhenatheretea) and Nardo strictae-Agrostion tenuis (belonging to the class Nardetea strictae). Wetland communities belonged to the classes Phragmito-Magnocaricetea (alliances Phragmition communis and Glycerio-Sparganion), Molinio-Arrhenatheretea (alliance Deschampsion cespitosae) and Scheuchzerio-Caricetea fuscae (alliance Caricion davallianae). The results demonstrate that the national expert system used can be successfully applied to a heterogeneous regional data set without discarding the particularities of the regional vegetation. The uniqueness of the regional vegetation is reflected in the set of diagnostic species determined at the regional level, which can differ strongly from those estimated at the national level.
In our contribution, we report on the 6th European Dry Grassland Meeting held from 31 August to 1 September 2009 in Halle (Saale), Germany. The meeting was attended by 40 participants, who gave 15 oral and 17 poster presentations. The rapid positive development of the European Dry Grassland Group (EDGG), the organiser of this conference, is mentioned: the inclusion of the EDGG in the International Association for Vegetation Science (IAVS) as a working group, the establishment of two new subgroups focussing on Mediterranean and South-East European dry grasslands, respectively, and the organisation of the first EDGG research expedition in 2010 belong to the most important events. In the last part of our contribution, we give a short introduction to the six articles of this Special Feature. Two of them deal with phytosociological classification of semi-natural grassland communities, one with vegetation- environment relationships. Two papers are concerned with conservational topics, one focussing on the population structure of endangered Pulsatilla patens, the other dealing with conservation of xeric grasslands in Transylvania. The last paper examines temporal changes in calcareous grasslands with regard to species diversity.
New vegetation data of dry grasslands in the Western Carpathians and the northern Pannonian Basin
(2010)
The paper presents new vegetation data from dry grassland sites in the biogeographical regions of the Western Carpathians and the northern Pannonian Basin, mainly belonging to the alliances Bromo pannonici-Festucion pallentis and Festucion valesiacae (Festuco-Brometea). The 124 phytosociological relevés were sampled between 2005 and 2009 in Slovakia, the SE Czech Republic, NE Austria, and N Hungary. They are classified into 16 associations and four transitional vegetation types. The paper also brings new information on the distribution of grassland associations in the study area. A new locality of the rare association Teucrio botryos-Andropogonetum ischaemi was confirmed. During our recent investigation of historical sites of the Alopecuro pratensis-Festucetum pseudovinae (Cynosurion cristati, Molinio-Arrhenatheretea) in the Slaná river floodplain, only one occurrence could be confirmed. Geographical principles in distribution of dry grassland associations and classification of the Stipa pulcherrima-dominated stands are also discussed.