Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft, Band 33 (2013)
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- Festuco-Brometea (3)
- eutrophication (3)
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- Caricion davallianae (2)
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As second part of a series focusing on the Pannonian grasslands of Austria, we present a detailed classification of the grasslands of the Vienna Woods (Wienerwald). This region, although geographically belonging to the Alps, has strong floristic affinities to the Pannonian Basin. The eastern slopes of the Vienna Woods are a hotspot of xero-thermophytic vegetation and exhibit the highest vascular plant species richness in Austria at a scale of 3' x 5'. We used the TWINSPAN classification of a large data set reported in the first part of this series as starting point. Relevés that were considered as misclassified at the level of alliances were manually re-arranged. From this table, an excerpt containing only the relevés of the Vienna Woods was used for the present study (1055 plots). We re-classified the relevés preliminary labelled as Arrhenatherion with another TWINSPAN run. Clusters for which no ecological difference could be detected were merged. The final delimitation of associations and subassociations was achieved by adjusting their diagnostic species so as to get units that were most informative in terms of environmental conditions. All re-arrangements were based on the summarised cover of diagnostic species within individual relevés. As a result, the grasslands of the Vienna Woods are classified within 22 associations (plus two subassociations) belonging to ten alliances and four classes. Within the Seslerio-Festucion pallentis, a new association Scorzonero austriacae-Caricetum humilis is described. The semi-dry grasslands of the study area previously classified as Onobrychido-Brometum are de-scribed as new association Filipendulo vulgaris-Brometum erecti and assigned to the Cirsio-Brachypodion. The Anthoxantho-Agrostietum tenuis is reported for Austria for the first time, and its syntaxonomy is discussed within a broader geographical context.
Syntaxonomic revision of the Pannonian grasslands of Austria : 1. Introduction and general overview
(2013)
The Pannonian part of Austria is a diverse landscape situated in the transition zone between the Alps, the Bohemian Massif and the Carpathian Basin. Although the grasslands of this region have been investigated in many botanical and vegetation studies, their phytosociological classification has remained confusing. With this paper, we start a series aiming at a developement of a revised, consistent system of the Austrian Pannonian grasslands. Here we present a general overview focusing on the higher syntaxonomic units. We define grasslands as all types of meadows, pastures, fens and primary steppes. We selected all available relevés of Pannonian grasslands from the Austrian Vegetation Database. Additional unpub-lished data were included from the Danube National Park and the Biosphere Reserve Vienna Woods. To account for the comparatively low number of relevés from the northern part of the Pannonian region of Austria (Weinviertel), we included also data from southern Moravia (Czech Republic). This set of 3384 relevés was classified using TWINSPAN. Relevés that were considered as misclassified at the alliance level according to the summarised cover of diagnostic species were manually re-arranged, and the data-set specific fidelity of species to alliances was calculated using the phi coefficient. The first TWINSPAN division largely corresponded to the traditional border between the classes Festuco-Brometea and Molinio-Arrhenatheretea. The conventional alliance concepts were generally well supported. As an exception, the distinction between Diantho-Seslerion and Bromo-Festucion pallentis was not reproduced at all. Therefore, we unite all rocky grasslands on calcareous soils in a single alliance Seslerio-Festucion pallentis. We also advocate the inclusion of all basiphilous semi-dry grasslands of the study area within a single alliance Cirsio-Brachypodion. Each of the corresponding TWINSPAN clusters showed a clear prevalence of Cirsio-Brachypodion species. Moreover, two separate alliances of semi-dry grasslands would have almost no regional character species.
This paper focuses on ecological requirements and phytosociological affinity of Avenula adsurgens subsp. adsurgens. Although this grass is widely distributed in central and south-eastern Europe reaching dominance in certain grassland types, the knowledge on its ecology and coenology is very poor. Moreover, some of the published data on its distribution are wrongly related to Avenula praeusta. We studied the taxon within an area of about 300 km2 (Central Slovakia) where it occurs in diverse habitats. Data from a systematic phytosociological survey were used to assess interspecific associations and ecological indicator values of the taxon. Detailed measurements from a transect along a spruce colonisation gradient were used to evaluate its relationship to a set of topographical, microclimatical, pedological and soil-microbiological characteristics. Tillers of A. adsurgens subsp. adsurgens were cultivated for two growing seasons to estimate characteristics of its clonal morphology and growth and its ability of spatial spreading. In the studied area, the taxon occurred mainly over the volcanic bedrock along a wide range of altitudes. It was concentrated in slightly managed or abandoned montane grasslands (800–1100 m) of the Violion caninae and Nardo strictae-Agrostion tenuis alliances. Phytosociologically the taxon seems not to be an important diagnostic species of these communities, rather an indicator of their successional development. Its highest cover was recorded in early to mid-successional stages without significant proportions of woody species. In stands with traditional management by mowing, grazing or their combination, the taxon was common (albeit with lower percentage cover), but more intensive ma-nagement including amelioration or fencing led to its retreat. Ellenberg ecological indicator values of A. adsurgens subsp. adsurgens were set as follows: light 7, temperature 5, continentality 4, moisture 4, soil reaction 5 and nutrients 3. Along a successional gradient, the taxon cover was positively correlated with percentage cover of herb litter, catalase activity, canopy openness and potassium content and negatively correlated with percentage cover of needles and canopy index reflecting the cumulative effects of spruce colonisation. The horizontal spreading of the taxon was enabled by the formation of spacers with a maximum length of 25.5 cm. We suppose that the ability to spread horizontally by spacers, together with the observed clonal plasticity, tall stature and fast growth by intensive tillering, belong to important attributes of A. adsurgens subsp. adsurgens promoting its success and dominant role in the abandoned grasslands.
The complex topography of floodplains provides conditions for high diversity and density of transitional areas between different grassland plant communities. Nevertheless, transitions have been almost completely neglected in previous studies of diversity patterns in semi-natural floodplain grasslands. We analyzed α-, β- and γ-components of plant species diversity in transitional areas between neighbouring wet and dry grassland communities in two landscapes of the Gauja River floodplain (Latvia) differing in landscape heterogeneity created by land use history and current management type (grazing versus mowing). In total 9 transition areas and their adjacent vegetation were sampled in 1 m wide and 8 to 28 m long belt transects gridded into 0.5 m × 1 m plots. Cluster analysis was used to analyze varia-tion in species composition of transitional areas and adjacent vegetation. Indicator species analysis was used to determine species specific to transitional areas (ecotonal species). Transitional areas of the homogeneous site had a more distinct species composition (clear division in clusters by cluster analysis) and significantly lower β-diversity than those of the heterogeneous site. α-Diversity was significantly higher in transitions than in wet grasslands and lower than in dry grasslands in both sites. Comparing the two sites, α-diversity was significantly higher in wet grasslands of the heterogeneous site, but no differences were found between transitions and dry grasslands in the two sites. Higher β-diversity of transitional areas in the heterogeneous site could be attributed to a higher density of different habitats per unit area in combination with grazing. No species were restricted to transitions, and no differences were apparent in the number of generalist species (indifferent species sensu Ellenberg indicator values for edaphic factors) between transitions and adjacent grasslands. Nevertheless, the total number of generalist species was considerably higher in the investigated flood-plain grasslands than usually reported for respective vegetation types in Latvia. It was concluded that transitions of neighboring floodplain grassland plant communities were more important in shaping β-diversity compared to α- and γ-diversity. Our results suggest that destroying transitional areas between dry and wet grasslands by leveling the ground or by abandonment of the management practices will decrease habitat heterogeneity and lead to less pronounced ecotonal pro-cesses in the whole riverine landscape. Thus further studies about the role of fine-scale transitional areas for biodiversity of floodplains are important for ecological restoration of floodplain grasslands.
Dry grasslands of NW Bulgarian mountains : first insights into diversity, ecology and syntaxonomy
(2013)
We present the data of the 3rd research expedition of the European Dry Grasslands Group (EDGG), which was conducted in 2011 in two contrasting areas in NW Bulgarian mountains. The aim was to collect plot data for comparing Bulgarian dry grasslands with those of other parts of Europe in terms of syntaxonomy and biodiversity. We sampled 15 nested-plot series (0.0001–100 m²) and 68 normal plots (10 m²) covering the full variety of dry grassland types occurring in the Vratsa area (Balkan Mts.) and the Koprivshtitsa area (Sredna Gora Mt.). In the plots all vascular plants, terricolous non-vascular plants and a set of soil and other environmental parameters were determined. By applying modified TWIN-SPAN, we distinguished 10 floristically well characterised vegetation types at the association level. After comparison with the regional and European literature, we propose to place them within three classes and five orders: Festuco-Brometea with the orders Stipo pulcherrimae-Festucetalia pallentis (xerophilous dry grasslands of base-rich rocks; alliance Saturejion montanae), Brachypodietalia pinnati (meso-xeric, basiphilous grasslands; alliances Cirsio-Brachypodion pinnati and Chyrsopogono grylli-Danthonion calycinae), Calluno-Ulicetea with the order Nardetalia stricae (lowland to montane Nar-dus swards; alliance Violion caninae), and Koelerio-Corynephoretea with the orders Sedo-Scleranthetalia (open communities of skeleton-rich, acidic soils; alliance unclear) and Trifolio arvensis-Festucetalia ovinae (closed, meso-xeric, acidophilous grasslands; alliance Armerio rumelicae-Potentillion). The Violion caninae with the association Festuco rubrae-Genistelletum sagittalis is reported from Bulgaria for the first time, while the two occurring Koelerio-Corynephoretea communities are described as new associations (Cetrario aculeatae-Plantaginetum radicatae, Plantagini radicatae-Agrostietum capillaris). According to DCA the main floristic gradient was largely determined by soil conditions, differentiating the Festuco-Brometea communities on soils with high pH and high humus content from the Koelerio-Corynephoretea communities on acidic, humus-poor soils, while the Calluno-Ulicetea stands are the connecting link. At 10 m2 Festuco-Brometea and Calluno-Ulicetea stands were richer in species across all investigated taxa and in vascular plants than Koelerio-Corynephoretea stands; the latter were richest in lichen species, while bryophyte richness did not differ significantly among syntaxa. Among the Bulgarian classes, the species-area relationships tended to be steepest in the Festuco-Brometea (i.e. highest beta diversity), but both alpha and beta diversity clearly fell behind the Festuco-Brometea communities in the Transylvanian Plateau, Romania, located less than 500 km north of the study region. Overall, our study contributes to a more adequate placement of the Bulgarian dry grasslands in the European syntaxonomic system and provides valuable data for large-scale analyses of biodiversity patterns.
Dry calcareous grasslands in Europe are renowned for their high plant diversity. However, declining habitat areas and highly fragmented distribution threaten the long-term persistence of this valuable habitat type. In Estonia the decline of traditional grassland management and subsequent encroachment of shrubs has resulted in a substantial loss of alvar grasslands – a particularly rare and species-rich type of calcareous grassland. It is known that a shrub cover of more than 70% decreases the alvar grassland species richness. At the same time, a shrub cover of 30% is considered optimal for alvar grasslands and thus a target state for habitat restoration. However, very little is known about the effect of low shrub cover on environmental conditions and species composition of alvar grasslands. Our aim was to detect to what extent the small-scale plant diversity and species composition is influenced by low shrub cover (less than 30%). We hypothesized that even a low shrub cover can have an effect on the environmental conditions of alvar grasslands. We sampled small-scale plant species richness, shrub cover and abiotic environmental conditions such as light, soil moisture, soil pH and soil depth in 10 metre long transects (n = 33) subdivided into 10 cm × 10 cm plots in Estonian alvar grasslands. Structural equation modelling was used to quantify the direct and indirect effects of shrub cover on the richness of characteristic alvar species and on the richness of generalist species. We found that low shrub cover of up to 30% increased total and generalist species richness directly and indirectly by increasing the light heterogeneity. Alvar characteristic species richness was not relat-ed to low shrub cover values. This suggests that when estimating the effects of shrub cover on species richness and on conservation needs of grasslands, habitat specificity of species needs to be taken into account.
Der diesjährige 8. Trockenrasen-Sonderteil von Tuexenia beginnt mit einen Bericht über die aktuellen Aktivitäten der European Dry Grassland Group (EDGG). Zunächst geben wir einen Überblick über die Entwicklung der Mitgliederzahl und den aktuellen Vorstand, der im Mai 2013 gewählt wurde. Dann berichten wir vom letzten European Dry Grassland Meeting in Prespa (Griechenland, 2012) und informieren über künftige Tagungen und Forschungsexpeditionen der EDGG. Schließlich war und ist die EDGG sehr aktiv darin, Special Features in internationalen Fachzeitschriften herauszugeben. Im zweiten Teil des Vorwortes geben wir eine Einführung zu den sechs Artikeln des diesjährigen Trockenrasen-Sonderteils: Zwei davon beschäftigen sich Biodiversitätsanalyen von Grasland-Ökotonen in einer Flusslandschaft in Lettland bzw. von brachgefallenen Alvar-Trockenrasen in Estland. Der dritte Artikel behandelt die Ökologie und Vergesellschaftung einer Grassippe (Avenula adsurgens subsp. adsurgens) im brachgefallenen, montanen Grasland der Karpaten (Slowakei). Die letzten drei Artikel schließlich sind der Beschreibung und Syntaxonomie von Trockenrasen gewidmet: Zwei davon bilden den Start einer neuen Serie über die pannonischen Trockenrasen Österreichs (Allgemeine Einführung und Trockenrasen des Wienerwalds), während der letzte die Ergebnisse der dritten EDGG-Forschungsexpedition im Jahr 2011 nach Bulgarien präsentiert. Schließlich geben wir einen Ausblick über künftige Pläne für das Special Feature.
Only a small proportion of introduced plant species become invasive and may eventually create ecological or economic problems. In many species it is still not clear which traits cause biological inva-sions. As a case study we focussed on the fast-spreading Epilobium brachycarpum in Central Europe to investigate the potential of this species to become a transformer or agricultural weed. We (1) documented the spread of the species in Central Europe, (2) modelled its range and (3) seed dispersal, (4) described its phytosociological alignment, (5) analysed the traits of invaded vegetation types, (6) described seed production, population densities and life cycle, (7) did competition and germination tests, and (8) drafted a risk assessment. Relevant traits and characteristics of E. brachycarpum are (i) formation of dense stands under ruderal conditions, (ii) high seed production, (iii) effective seed dispersal, (iv) high competitiveness on bare soils against other ruderal plants, and (v) ecological niche shift com-pared to its native range. We expect E. brachycarpum to settle in the Mediterranean, sub-Mediterranean and many parts of temperate Europe within the next decades in habitats strongly altered by human activities, especially open stands of the alliance Sisymbrion. We predict that E. brachycarpum will become a noxious weed in vineyards, and that it will also colonise vegetation of the alliances Bidention and Carici-Epilobion.
Summed frequency data of apomictic taxa derived from vegetation relevées from Central Europe were correlated with ecological traits – water content of soil, calcium and magnesium content of soil or water, nutrient content of soil or water, environmental dynamics, hemeroby, frequency of stress-tolerant species, salt tolerance, altitude, height, and frequency of annual taxa – of alliances of the Central European vegetation. The partly problematic identification of taxa where apomixis is important for seed production was based on a literature review. In Central Europe, high altitudes favour apomictic taxa. Otherwise, no correlations between ecological factors attributed to the alliances of the European phytosociological system and frequencies of apomictic taxa in the alliances of the European phytosociological system were found. Analyses could not confirm theories on ecological preferences of apomictic taxa; e.g., that competition penalizes apomicts, apomicts have better colonizing abilities than sexual plants, or apomicts have larger ranges than their sexual relatives could not be confirmed.
Evidence for increasing homogenization and de-ruralization of the Central European village flora
(2013)
In this study, the spontaneous flora of North Rhine-Westphalian villages (NW Germany) recorded in the periods 1980–1984 and 2004–2005 was analyzed. We asked: (i) Did the similarity of the village flora increase with time and to what extent did non-native species contribute to this? (ii) Is the ongoing trend of urbanization reflected in the village flora? (iii) Regarding the species composition and β-diversity: are there differences between the results of a repeated survey and of a type comparison? In both periods, 200 villages were visited once, using consistent criteria for village selection and floristic investigation. Of these, a subset of 61 villages was investigated in both time periods and the rest were selected randomly for the second survey but with respect to the same criteria as used in the first. Using different β-diversity indices (Sørensen index of dissimilarity, Simpson index of dissimilarity and nestedness resultant index) to disentangle pure species turnover and nestedness of species assemblages, we tested whether the similarity among the villages increased over the years. This was done by calculating all pairwise comparisons among the villages of each time period, i.e. their spatial turnover. Additionally, different ecological groups were defined (e.g. "neophytes", "C-strategists" or "urbanophilous species") using the subgroups of species traits (floristic status, Grime's life strategy and urbanity) to indentify urbanization and compositional changes. Our results show that the traditional village flora (species of the Arction lappae, Bidention tripartitae and Potentillion anserinae) is further blurred towards unspecific ubiquitous assemblages found in the periphery of man and that the floristic urbanization is still ongoing. Supported by nearly all ecological groups regarded, our results corroborate that the species composition of Central European villages underwent a considerable degree of homogenization. To some extent this is caused by structural homogenization of villages. Regarding the considerable increase of common ubiquists and α-diversity in general, however, changes in weeding practices seem to be the main reason. Based on the reinvestigated subset we could show that comparable results can be obtained by a consistent use of criteria for the selection of villages, even if unpaired samples were used.
