Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft, Band 35 (2015)
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We performed a survey of grassland communities in the Ukrainian Carpathians with the aim of: (1) syntaxonomically classifying the meso- and subxerophilous grassland vegetation; (2) analysing the main gradients in their species composition; (3) estimating the effect of selected environmental factors on grassland species composition; (4) assessing the species richness of vascular plants and bryophytes in relation to the measured environmental variables. We collected 46 phytosociological relevés during the growing seasons of 2010 and 2011. Species composition and species richness were studied at two spatial scales (1 m² and 16 m²) in relation to soil parameters (soil depth, pH (KCl), content of P, K, Mg, N and C), management regime (mowing, grazing, ploughing in the past and burning), and other factors (altitude, litter cover, open soil, inclination, solar radiation and animal excrement). Seven grassland types were distinguished belonging to 3 classes and 4 alliances, namely the Nardetea strictae including the Violion caninae (mesic pastures at altitudes of 400–600 m mostly on moderate slopes) and the Nardo strictae-Agrostion tenuis (grasslands on moderate slopes at altitudes of 700–900 m usually managed by mowing and grazing the aftermath); the Molinio-Arrhenatheretea, including the Arrhenatherion elatioris (submontane grasslands originated mostly on former fields after their abandonment in the past) and the Cynosurion cristati (intensive pastures); and the Festuco-Brometea including the Cirsio-Brachypodion pinnati (abandoned grasslands dominated by Brachypodium pinnatum and Inula salicina). Detrended correspondence analysis indicated that the major compositional turnover was related to altitude and soil reaction. A canonical correspondence analysis confirmed that altitude had the strongest effect on species composition in the analysed dataset, followed by management treatments (former ploughing, grazing intensity). For vascular plant species richness, regression tree analysis identified grazing intensity as the most important predictor at the 1 m² scale. At the 16 m² scale, soil humus content was evaluated as the most important predictor of vascular plant species richness, followed by litter cover and grazing intensity. The number of bryophytes was not determined by the studied environmental factors at either of the two spatial scales. Although the number of analysed relevés in this study was limited, our results significantly contribute to the understanding of submontane grasslands in the Ukrainian Carpathians.
The demography of the alpine pioneer species Saxifraga aizoides was investigated along a successional gradient at the Rotmoos glacier foreland (2,330–2,450 m a.s.l., Obergurgl, Ötztal, Austria) from recently deglaciated areas to advanced successional stages. A basic hypothesis of our study was that fecundity might play an essential role for population growth rate on the youngest site and become of minor importance at advanced successional stages. A matrix modelling approach was performed to calculate the main demographic parameters on 6, 33, and 81 year old moraines. Our results partly confirmed the prediction of the larger role of fecundity on the youngest sites. Here, seedling mortality was lower compared to the older sites, and the reproductive success was significantly higher. All in all, Saxifraga aizoides mainly follows a "persistence strategy" from the beginning, characterized by the fact that large individuals did not undergo mortality at the recently deglaciated site. However, in the long term a population decline will occur due to plant age and changes of environmental conditions along the successional gradient.
Steppes used to cover large areas of Hungary, but most of this vegetation has since been destroyed. In Central Hungary, some patches have survived on ridges in wet meadows. These habitat complexes face profound land use changes and their optimal management regime is uncertain. We identified seven annually mown steppe and wet meadow types according to their grazing regime and history and aimed to answer the following questions: (1) Does grazing have beneficial effects on mown steppes and wet meadows? (2) Should the presently homogeneous management of neighbouring steppes and wet meadows be maintained? (3) Is annual mowing sufficient in assisting the recovery of steppes and wet meadows on former croplands?
We selected three localities for each of the seven vegetation types and sampled them with 50 quadrats (50 × 50 cm) in each locality, making a total of 1,050 quadrats. Vascular plant diversity relations were evaluated using the total number of species per habitat type (species richness) and the average number of species per quadrat (microsite diversity). The effect of grazing and history on microsite diversity was tested with linear mixed-effect models. We used Redundancy Analysis to disentangle the role of grazing intensity and management history on species composition. Plant species were then sorted into functional groups, and the proportions of these groups were used to evaluate community structure.
Our results indicate that mowing alone cannot maintain as high a diversity as the combination of the two land use types, thus grazing should be introduced to non-grazed areas. Steppes, however, were found more sensitive to the intensity of grazing than wet meadows. Under heavy grazing, no increased microsite diversity was detected in the steppes and the proportion of disturbance indicators tended to increase. In contrast, the same grazing intensity resulted in only positive effects in wet meadows. Thus, uniform land use on adjacent steppes and wet meadows is not recommended but intensive grazing should be stopped on steppes. Secondary steppes were less diverse than primary ones and their community structure was also poorer, whereas wet meadows had a better regeneration potential. Thus, mowing alone is an incomplete tool to restore the plant diversity of secondary steppes; they should also be grazed and/or should be supported by other active interventions.
Thermophilous deciduous forests of Quercetalia pubescentis are widespread in Bosnia and Herze-govina (B&H), where they occupy about 11% of the national territory and account for about 20% of the total forest area. This paper provides their formalized classification and nomenclatural revision, based on 274 relevés from the literature and 399 relevés collected during intensive field research. The Cocktail method was used for supervised classification, which resulted in 17 associations recognized for B&H. Additionally, one new association emerged after semi-supervised classification of relevés not classified by Cocktail. The following associations were recognized, and characterized by species composition, ecology and distribution: 1. Querco pubescenti-Carpinetum orientalis; 2. Rusco aculeati-Carpinetum orientalis; 3. Carici hallerianae-Quercetum pubescentis; 4. Cruciato glabrae-Carpinetum orientalis; 5. Seslerio autumnalis-Quercetum pubescentis; 6. Aristolochio luteae-Quercetum pubescentis; 7. Asparago tenuifolii-Quercetum pubescentis; 8. Seslerio autumnalis-Ostryetum carpinifoliae; 9. Rusco aculeati-Ostryetum carpinifoliae; 10. Querco pubescenti-Ostryetum carpinifoliae; 11. Quercetum frainetto-cerridis; 12. Fraxino orni-Quercetum cerridis; 13. Lathyro nigri-Quercetum petraeae; 14. Aceri obtusati-Quercetum petraeae; 15. Cytiso hirsuti-Quercetum petraeae; 16. Festuco drymejae-Quercetum petraeae; 17. Potentillo micranthae-Quercetum petraeae; 18. Seslerio autumnalis-Quercetum petraeae. The validity and legitimacy of associations were checked and they were validated and corrected as needed, strictly following the rules of the International Code of Phytosociological Nomenclature. A complete list of synonyms has been given for every association, with an indication of the article of the Code according to which the name must be rejected. The associations were assembled into four groups, following the criterion of dominant species in a tree layer, in order to present differences and similarities in floristic composition between associations of the same type, i.e., dominated by the same tree species. An ecogram was drawn displaying the relative ecological range of each association along soil pH and moisture gradients. The largest number of associations (13) occurs in the Mediterranean region; the Dinaric and Pre-Pannonian regions each harbour ten associations, while there are only five associations in the Transitional Illyrian-Moesian region. Seven syntaxa previously reported for thermophilous deciduous forests of B&H were not recognized during the analysis. A list is given of all nomina nuda that could not be resolved and ascribed to synonymy with accepted associations.
Since anthropogenic activities have become concentrated along rivers, river regulations have strongly reduced the lateral connectivity by separating rivers from their floodplains. Consequently riparian habitat heterogeneity and the related species diversity are degrading, especially in highly modified prealpine rivers. Riverbank revitalisation measures aim at mitigating this degradation and river restoration projects have become widespread. Nonetheless, little knowledge exists about their specific outcome, as standardised monitoring programs are missing. The aim of this study is to systematically compare vegetation change in response to three contrasting measures of bank diversification, i.e. embankment removal, sand input or gravel addition. Moreover, the influence of these measures on adjacent vegetation is studied. Conclusions were drawn on the basis of three common goals of restoration projects: (i) improvement of vegetation structure, (ii) increase of species diversity, and (iii) characteristic species composition. The field work was done along River Inn northeast of Munich. Vegetation structure, species identity and cover as well as selected habitat variables were recorded in a stratified randomised sampling design; variation between measures was analysed using uni- and multivariate statistics. We detected great differences in the effect of the three measures two years after implementation. Embankment removal initiated highly dynamic habitats where plant establishment was difficult. The input of sand led to a rather homogenous species composition, at least partly because the habitats were productive and therefore most likely will develop to tall reed stands or riparian forests. After gravel addition the restored sites remained relatively open, while riparian pioneer species could colonise. Vegetation structure and composition of adjacent reed stands were positively affected. The results indicate how restoration outcomes can vary depending on the specific measures chosen. This confirms the need for careful consideration of the pursued goals and site-specific conditions prior to implementation as well as long-term monitoring after implementation.
This Special Feature is the tenth in a series devoted to dry grasslands and edited by members of the European Dry Grassland Group (EDGG; http://www.edgg.org) or its prede-cessor Arbeitsgruppe Trockenrasen that have been published in Tuexenia since 2005 (GAL-VÁNEK et al. 2012). With this issue we celebrate our tenth anniversary of the Tuexenia Dry Grassland Special Features.
The Cocktail method was applied to a small data set derived in a regional survey on riparian forest in the Polish part of the Sudetes. Formalised classification revealed the occurrence of seven associations. Considering the ecological character, three distinct groups emerged among them: i) alluvial forests (Salicetum albae, Alnetum incanae), ii) forests of small and medium mountain streams with only a narrow riparian zone (Salicetum fragilis, Stellario nemorum-Alnetum glutinosae and Fraxino-Alnetum) and iii) forests developed on waterlogged soils of spring-fed areas (Carici remotae-Fraxinetum and Piceo-Alnetum). The associations Salicetum fragilis and Piceo-Alnetum are reported for the first time from Poland. Analysis of GIS-derived environmental variables showed that average altitude, stream power index (SPI) and river order were significantly different among the associations, while there were no differences among average values of slope, solar radiation and topographic wetness index (TWI). Significant differences in species richness among the associations were also identified. Application of the Cocktail method in regional studies was also discussed.
The historical transition from the Bulgarian Kingdom through the Soviet period to the present state of Bulgaria has affected humans and their land use preferences, leading to repeated transformations of the vegetation. We analysed the proportional change of vegetation types in the Tsentralen Balkan National Park in Bulgaria using aerial imagery over the last 65 years and object based image segmentation. Segments were classified into three land cover classes (vegetation types): shrubland, grassland, and shrub-grassland mosaic. In order to interpret the observed proportional changes of these vegetation types we collated livestock numbers over the same period. The shrub-grassland mosaic constantly decreased over the first 20 years, whereas shrublands and grasslands both increased. During the period 1969–1989, the trend continued and areas covered by the shrub-grassland mosaic decreased by 82%, while shrublands increased by 56% and grasslands increased by 18%. The species rich shrub-grassland mosaics were most affected by the land use changes. The overall land cover diversity pattern reduced to two classes. The period with the least changes was 1989–2012, when changes in landscape cover stabilized after the area was designated a National Park. Livestock numbers varied throughout the study period due to the transformation processes. This probably also affected the change in the vegetation patterns analyzed, as few other drivers are known from the Stara Planina Mts. The aerial imagery time series was helpful to reconstruct the changes in the vegetation of the study area, however, extending the time series would allow for a better correlation with livestock numbers.
Knowledge about the drivers of vegetation dynamics in grasslands is fundamental to select appropriate management for conservation purposes. In this study, we provide a detailed analysis of vegetation dynamics in alkali grasslands, a priority habitat of the Natura 2000 network. We studied vegetation dynamics in five stands of four alkali grassland types in the Hortobágy National Park (eastern Hungary), between 2009 and 2011. We analysed the effect of fluctuations in precipitation on both the overall vegetation composition and on the cover of each species using Self Organizing Map neural networks (SOM). We found that SOM is a promising tool to reveal plant community dynamics. As we analysed species cover and overall vegetation composition separately, we were able to identify the species re-sponsible for particular vegetation changes. Fluctuations in precipitation (a dry season, followed by a wet and an average season) caused quick shifts in plant species composition because of an increasing cover of halophyte forbs, probably because of salinisation. We observed a similar effect of stress from waterlogging in all studied grassland types. The species composition of Puccinellia grasslands was the most stable over the three years with varying precipitation. This was important as this grassland type contained many threatened halophyte species. Self-organising maps revealed small-scale vegetation changes and provided a detailed visualisation of short-term vegetation dynamics, thus we suggest that the application of this method is also promising to reveal community dynamics in more species-rich habitat types or landscapes.
Muránska planina Mts, a small karstic area situated in the southern part of the Western Carpathians in Central Slovakia was chosen as a model region for the study of the variability and diversity patterns of thermophilous and mountain non-forest vegetation on the crossing of the Carpathian and Pannonian bioregions. Altogether, 113 new relevés were sampled using standard methods of the Zürich-Montpellier approach and compared with previously published data. The dataset containing both new and published phytosociological relevés from dry, semi-dry and mesic grasslands (265 relevés) was analysed using the program JUICE 7.0.98. The Beta flexible method, relative Sorensen distance as a similarity measure, and logarithmic transformation of species covers were used for the numerical classification (PC-ORD). The main environmental gradients of species composition were analysed by DCA in the CANOCO 4.5 package using the Borhidi indicator values. The various mosaics of plant communities were detected in succession series from pioneer rocky stands through open rocky grasslands dominated by Festuca pallens, F. tatrae, Carex humilis and Sesleria albicans to closed tall grass communities dominated by Calamagrostis varia and C. arundinacea. Plant communities belonging to six classes (Sedo-Scleranthetea, Festuco-Brometea, Elyno-Seslerietea, Thlaspietea rotundifolii, Mulgedio-Aconitetea and Molinio-Arrhenatheretea) including Pannonian grasslands of the alliance Bromo pannonici-Festucion pallentis and high montane/subalpine grasslands of the alliance Astero alpini-Seslerion calcariae occur together in the study area. High floristic richness and extraordinary diffusion of thermophilous and montane/subalpine elements is characteristic for the majority of the studied plant communities.