Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft, Band 33 (2013)
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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.
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.
To examine the necessity of livestock grazing for managing threatened sand vegetation so as to en-sure and develop its nature-conservation value, we investigated a grazing system in a model nature reserve (German upper Rhine valley) characterized by threatened steppic sandy grassland (Allio-Stipetum vegetation complex: Habitats Directive Annex I, priority type 6240, additionally Koelerion glaucae: priority type 6120). The area has been grazed by sheep and additionally by donkeys since late summer of the year 2000. We established ungrazed (Au) and grazed plots (Ag) in the Allio-Stipetum complex in a systematic grid-plot design before grazing impact started. We sampled phytosociological relevés yearly in the Au/Ag plots for 12 vegetation periods. Addi-tionally, we sampled relevés on former farmland adjacent to the Allio-Stipetum complex (systematic grid-plot design) over ten vegetation periods. These former fields (Fg) were integrated in the grazing system since the beginning of the study. A constancy table was produced for Au, Ag, Fg. To determine the portions of target species (Koelerio-Corynephoretea, Festuco-Brometea species) we calculated target-species ratios (proportion of target species in comparison with the total species number; qualitative or quantitative approach: TSRqual/quant). We tested the effects of grazing, year and interactions on structural and phytodiversity characteristics of the relevés by mixed linear models. The results of the long-term experiment confirmed significant beneficial effects of grazing on habi-tat-typical structure and phytodiversity: e. g. reduction of litter, support of species which are short in height (< 20 cm), reduction of taller species (> 50 cm), support of the diversity of all plant species, of non-graminoid herbs and of target plant species, reduction of Calamagrostis epigejos, positive effects on TSRqual and TSRquant values. Similar developments, e.g. for phytodiversity and Calamagrostis epigejos cover, were observed on the former fields, but there are still seed limitations and high ruderal-plant dominances. In general TSRqual/quant show remarkable increases, but do not reach the values of the Ag plots. Concerning aims of nature conservation, the habitat-typical vegetation structure and phytodiversity of the Allio-Stipetum shows an excellent development as a consequence of the used grazing manage-ment. However, occasionally small populations of target species did not increase (e.g. Koeleria glauca). The former fields show a development towards valuable sandy grassland.
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.
Das Monitoring von Ökosystemeigenschaften leistet einen wichtigen Beitrag zur Renaturierung von Ökosystemen. Dabei ist es entscheidend, nicht nur Vegetationsdaten, sondern auch Standortfaktoren, wie zum Beispiel Licht, direkt zu erfassen. Das Projekt "Dynamisierung der Donauauen zwischen Neuburg und Ingolstadt" (Bayern) wurde mit der Zielsetzung implementiert, das typische Flutungsregime und die damit verbundenen Grundwasserschwankungen eines naturnahen Auwaldes wiederherzustellen. Ein Teilprojekt des darauf abgestimmten Monitoringprogramms konzentriert sich seit 2007 auf die Beobachtung von Vegetationsveränderungen an einem neu angelegten Umgehungsgewässer, die entlang von rechtwinklig zum Gewässer verlaufenden Transekten erfasst werden. Hierbei wurde der Standortfaktor Licht anhand der sogenannten "Wörlein-Skala" abgeschätzt. Das Ziel dieser Arbeit war es, eine quantitative Methode auf der Basis der digitalen Hemisphärenphotographie zu entwickeln, die genauere Ergebnisse als die Schätzung liefert und dabei zeitsparend und flexibel eingesetzt werden kann. Aufgrund der so erhobenen Daten sollten folgende Fragen beantwortet werden: (1) Liefert die Wörlein-Skala im Vergleich zu den Messdaten eine verlässliche Datengrundlage? (2) Stellen Ellenberg-Lichtzeigerwerte eine sinnvolle Alternative zur direkten Messung oder Schätzung des Standortfaktors Licht dar? In einer Vorstudie wurde die Vergleichbarkeit spezieller Kameraaufbauten unter verschiedenen Umweltbedingungen getestet. Die Bearbeitung der digitalen Photographien erfolgte mit dem Programm "SideLook" zur Schwellenwertermittlung und der Modellierungssoftware "Gap Light Analyzer". Die Prüfung der Verlässlichkeit der Wörlein-Skala und der Ellenberg-Zeigerwerte erfolgte anhand von induktiver Statistik. Der Methodenvergleich ergab deutliche Unterschiede in der Erfassung des Standortfaktors Licht im Auwald: Die Wörlein-Skala repräsentierte die aus den Photographien abgeleiteten Messwerte relativ gut, nur die Schätzungen für die schattigeren Bereiche waren weniger gut aufgelöst. Die Ellenberg-Lichtzeigerwerte korrelierten nur schwach mit den Messwerten sowohl bei logarithmischer Korrektur der Deckung, als auch bei Gewichtung entsprechend der Deckung der Pflanzenarten. Zusammenfassend erfüllt die digitale Hemisphärenphotographie die meisten Anforderungen an Messungen des Standortfaktors Licht. Die Wörlein-Skala kann als verlässliche Alternative betrachtet werden, solange ihr logarithmischer Verlauf entsprechend des Weber-Fechner`schen Gesetzes beachtet wird. Der Ellenberg-Zeigerwert eignet sich dagegen weniger zur Erfassung des Standortfaktors Licht in Auwaldgebieten.
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.
Im südöstlichen Österreich, im angrenzenden Westungarn und Nordostslowenien wurden insgesamt 31 Bestände mit Fritillaria meleagris pflanzensoziologisch erfasst, ausgewertet und durch Bodendaten ergänzt. In folgenden Pflanzengesellschaften konnte die Schachblume nachgewiesen werden: Pruno-Fraxinetum, Pseudostellario-Carpinetum, Galio palustris-Caricetum ripariae, Lysimachio vulgaris-Filipenduletum caricetosum acutiformis, Iridetum sibiricae, Serratulo-Festucetum commutatae, Silaetum pratensis, Festuco pratensis-Alopecuretum pratensis. Die Auswertung zeigt, dass F. meleagris im Untersuchungsgebiet eine breite phytocoenologische Amplitude hat und nicht als Charakterart einer bestimmten Assoziation aufgefasst werden kann. Alle Standorte weisen Eingriffe in den Bodenwasser-haushalt in Form von Entwässerungsmaßnahmen auf, die sich aufgrund der sand- und schluffreichen, meist hydromorphen Böden z. T. erst allmählich auf die Artenzusammensetzung der Flächen auswir-ken. Besonders die Vorkommen im Arrhenatherion sollten dringend einem Monitoring unterzogen werden, um einen weiteren Rückgang der Art erkennen und verhindern zu können.
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.
The article deals with Norway spruce (Picea abies), silver fir (Abies alba) and larch (Larix decidua) forests of the orders Piceetalia and Athyrio-Piceetalia (Vaccinio-Piceetea) in Slovenia. A total of 934 relevés of spruce, larch and fir forests within the Piceetalia and Athyrio-Piceetalia were collected from the literature. After resampling, 319 relevés remained, originating from 28 associations. Classification revealed two major groups of spruce, larch and fir forests, one thriving on non-carbonate bedrock and the other on carbonate. We further divided forests on non-carbonate substrate into two major groups – one thriving at high altitudes and the other in lowlands, both assigned to Piceion abietis. The second major group contains mesophilous, species-rich communities found mostly on carbonate bedrock. This major group can be further divided into four groups. The group of secondary forest on sites of beech forests, as well as the group of forest found in frost hollows can be assigned to Abieti-Piceion. The group of herb-rich, mesophilous communities forming zonal spruce and larch forests can be assigned to Chrysanthemo-Piceion and the group of forests on boulder scree to Calamagrostio-Abietion. Analysis of structural, functional, phytogeographical and geomorphological features, as well as ecological condi-tions estimated by bioindicator values, demonstrated the usefulness of this classification.
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.