Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft, Band 37 (2017)
Refine
Year of publication
- 2017 (24)
Document Type
- Article (24)
Has Fulltext
- yes (24)
Is part of the Bibliography
- no (24)
Keywords
- climate change (2)
- eutrophication (2)
- grassland management (2)
- grazing (2)
- quasi-permanent plots (2)
- succession (2)
- syntaxonomy (2)
- Alnion incanae (1)
- Alnus glutinosa (1)
- Alnus incana (1)
Die Floristisch-soziologische Arbeitsgemeinschaft wurde am 13. August 1927 in Göttingen gegründet und besteht nun, mit einer Unterbrechung zwischen 1941 und 1948, seit 90 Jahren. In diesem Rückblick wird vor allem die Entwicklung nach dem 2. Weltkrieg näher dargestellt. Hauptkapitel sind Verein, Satzung und Vorstände, Mitgliederentwicklung, Jahrestagungen, Arbeitskurse und Workshops, die Publikation der Mitteilungen und von Tuexenia mit ihren Beiheften sowie der Synopsis der Pflanzengesellschaften Deutschlands. Insgesamt wird eine sehr erfolgreiche Entwicklung mit Konstanz wesentlicher, schon zu Beginn formulierter Ziele und dynamischen Anpassungen an neue Gegebenheiten festgestellt.
Wet grasslands once covered a large area in the lowlands of northern Germany, but have declined since several decades as a result of land use intensification. Permanent plot data from such grasslands in the region that would allow to assess the extent of changes in species composition and richness are still rare. Here, we present a re-visitation study of 52 quasi-permanent plots from the Stedinger Land area in the basin of the river Weser near Bremen, comparing quadrat data between 1948 and 2015. In 1948, the grasslands were characterized by species typical of wet, moderately fertile grasslands belonging to the Bromo-Senecionetum aquatici (Bromion racemosi), including 15 species currently classified as threatened. Until 2015, the vegetation had changed strongly: almost all indicators of wet grasslands had either declined or completely vanished, whereas more nutrient-demanding species of less wet soils had increased, especially grasses. The cumulative number of species had declined by 50%, while mean plot species richness had decreased by 64.6%, mainly resulting from the pronounced loss of many herbs. A comparison of mean Ellenberg indicator values suggested that the plots had become drier, but also more base- and nutrient-rich, most likely triggered by the intensification of land use with drainage and fertilization as well as more frequent and earlier cutting. Our study reflects the dramatic loss of plant species diversity in wet grasslands over the past 60−70 years in areas not preserved and properly managed, and it documents the need for protecting remnants of these grasslands and for restoring wet grassland areas by re-wetting, nutrient removal and the transition to a less intensive land use.
The aim of our study was to reveal the differences in the species composition and soil properties of open sandy grasslands dominated by different Festuca species, Festuca vaginata and F. pseudovaginata. Due to the arid conditions, sandy grasslands are generally covered by xerothermic vegetation in which F. vaginata is a typical dominant species. Festuca pseudovaginata, a species newly described by the authors, can also gain dominance in sandy grasslands. However, species composition and soil properties of grasslands dominated by this recently discovered species are still undiscovered. Based on previous coenological studies, we hypothesised that the grasslands characterised by the endemic F. vaginata are more species-rich than those with F.pseudovaginata.
Coenological sampling was carried out in May 2009 at two study sites using the Braun-Blanquet method in quadrats of 2 m × 2 m. Five relevés were sampled in stands dominated by F. vaginata and F. pseudovaginata respectively at two study sites in Central Hungary, resulting in a total of twenty relevés. Analyses were based on the cover scores of vascular plant species and cryptogam crust and values of seven soil properties (pH [KCl], pH [H2O], humus, total N, Ca, P2O5 and K2O) measured in the 0–15 and 15–30 cm soil layers. Soil properties of the grasslands dominated by F. pseudovaginata and F. vaginata (dependent variables) were compared by linear mixed models, where ‘grassland type’ was the fixed factor and ‘site nested in grassland type’ was considered as random factor. Data were analysed by cluster analysis, fusion algorithm was a combinatorial method (minimising increase of variance), and the correlation was used as comparative function. We compared the cover of subordinate species by Mann-Whitney U test. We found that F. pseudovaginata and F. vaginata samples were well separated, and grasslands dominated by F. pseudovaginata had nearly two times more species than those dominated by F. vaginata. Based on the cluster analyses using plant cover and upper 0–15 cm soil layer data, F. pseudovaginata and F. vaginata groups could be well separated. Linear mixed models revealed that F. vaginata grasslands were typical on soils with higher pH, nitrogen, phosphorous and potassium contents compared to F. pseudovaginata grasslands, which indicates a tight connection between the properties of the upper soil layer and the vegetation in sandy grasslands.
Die in Amerika heimische Kolumbianische Zwergwasserlinse (Wolffia columbiana) tritt neuerdings in Europa als Neophyt auf und konnte in Niedersachsen zum ersten Mal im Jahr 2016 nachgewiesen werden. Im Hintergrund stehen die für den Naturschutz relevanten Fragen, wie viele vermeintliche Vorkommen von Wolffia arrhiza in Wirklichkeit Wolffia columbiana repräsentieren und ob dieser Neophyt die heimische und gefährdete Art Wolffia arrhiza verdrängen kann.
Vegetation patterns of floodplain forests are highly variable across different habitats in European regions. Their plant communities have been well described from the phytosociological point of view, but plant species richness and composition patterns and their underlying environmental factors are still insufficiently known. Sixty-one vegetation plots of black alder-dominated floodplain forests were sampled in central Slovakia in order to find main environmental predictors affecting floristic diversity of their vegetation. For each vegetation plot with a constant size (400m2), vascular plant species and a set of topographic, climatic, soil physical and chemical characteristics were recorded. A generalized linear model was applied to explain relevance of environmental factors on changes of species richness, whereas the relationship between species composition and explanatory variables was tested using ordination methods. Main gradients of species compositional variation were soil moisture, light, elevation and soil chemistry-related variables. Vascular species richness of plots varied between 19 and 59 (mean 38). Herb-layer species richness was positively related to the soil pH, stream power index and negatively to the concentration of soil iron. These linear trends were accompanied by a hump-shaped response to sand content and a U-shaped response to elevation.
The flora in the Caucasus Ecoregion is rich in economically important plants. While its value in terms of food crops and medicinal plants has recently been subject to scientific research, the ornamental value of many Caucasian plant species has not yet been fully recognized. In order to assess the ornamental value of the Caucasian flora, vegetation data from two mountainous study regions in Georgia (n = 958 species, mostly grassland vegetation) was compared with the product range of ornamental plants in Germany using an online plant shopping guide. Characterization of the 150 plant species listed in both databases revealed that 121 species are present in central Europe and 117 species are natives or archaeophytes in Germany. Thus, only few species are Caucasian endemics. Furthermore, a list of 79 potential ornamentals endemic to the Caucasus was compiled from the literature. In order to place them in context of the horticultural market, the species characteristics were examined. Following this, a critical discussion of the potentials and risks arising from trade with ornamental plants was carried out with regard to nature conservation, biological invasion control, genetic resource maintenance and socioeconomic significance.
Steilhänge der Mittelgebirge weisen eine kleinräumige standörtliche Vielfalt auf und wurden aufgrund ihrer exponierten Lage bereits frühzeitig durch den Menschen u. a. als Befestigungsanlage genutzt. Daraus resultierte häufig eine hohe floristische und vegetationskundliche Diversität mit hohem Naturschutzwert. Durch Umwelt- und Nutzungsveränderungen hat sich aber auch an diesen Standorten in den letzten Jahrzehnten ein starker Wandel vollzogen. Durch Auswertung alter Florenlisten und Vegetationsaufnahmen und durch aktuelle Erhebungen wollen wir die Vegetationszusammensetzung der Lengder Burg, eines Steilhangs auf Unterem Muschelkalk im südlichen Göttinger Wald (Süd-Niedersachsen, Deutschland), und ihre Veränderung aufzeigen und Rückschlüsse für die zukünftige Behandlung ziehen. Dazu wurden Angaben zur Gefäßpflanzenflora aus dem Zeitraum 1950 bis 1995 mit einer aktuellen floristischen Kartierung des Gesamtgebiets von 2016 verglichen. Die Vegetationszusammensetzung wurde anhand von 37 Vegetationsaufnahmen aus dem früheren Zeitraum harakterisiert. 29 dieser Flächen wurden 2009 bis 2016 erneut aufgenommen. Räumliche und zeitliche Unterschiede in der Diversität und Artenzusammensetzung wurden hinsichtlich verschiedener standörtlicher Parameter und ökologischer Artengruppen analysiert.
Die Vegetation lässt sich zwei Gruppen zuordnen: 1. Das Carici-Fagetum und seine Kontaktgesellschaften an südlich und westlich exponierten Steilhängen. 2. Das Hordelymo-Fagetum mit verschiedenen Ausbildungen auf dem Plateau und an flacheren Süd- und Nordhangbereichen. Im Carici-Fagetum ist ein deutlicher Diversitätsverlust und eine Zunahme in der Dominanzstruktur der Krautschicht zu erkennen, der im Vergleich der Aufnahmezeiträume auf eine zunehmende Homogenisierung der Vegetation hinweist. Zurückgegangen sind dabei besonders die typischen Kenn- und Trennarten dieser Waldgesellschaft bei gleichzeitiger Zunahme der Buche in der Verjüngung. Im Hordelymo-Fagetum bewirkt neben Gehölzen in der Strauch- und Krautschicht vor allem die Zunahme von Allium ursinum eine homogenere Artenzusammensetzung, jedoch ohne Diversitätsverlust. Neben Stickstoffeinträgen, dem Klimawandel sowie einem reduzierten Rehwild-Verbiss bedingt besonders der Nutzungswandel diese Veränderungen. Vor allem im Carici-Fagetum wirkte sich der Übergang zwischen früherer Nieder- und Mittelwald-Nutzung mit Waldweide über eine fast 100jährige Hochwald-Nutzung bis zum jetzigen Schutzwald stark aus. Gleichwohl weisen die steilen Hänge weiterhin einen hohen Anteil an Rote-Liste-Arten auf und tragen wesentlich zur hohen Biodiversität des Gebiets bei. Veränderungen in der Vegetation der Lengder Burg spiegeln die Veränderungen im Göttinger Wald insgesamt wider. Kleinflächige Offenhaltungsmaßnahmen zur Erhaltung wertvoller floristischer Elemente sind teilweise erfolgreich. Kleinwüchsige, lichtbedürftige Magerkeitszeiger verschwinden jedoch zunehmend aus den sich entwickelnden, hochwüchsigen Stauden-Säumen. In den benachbarten, unbewirtschafteten Hangbuchenwäldern sorgt die fehlende Nutzung nach Jahrhunderten der Auflichtung und Aushagerung für eine Sukzession in Richtung mesophilen Kalkbuchenwalds.
The vast majority of European grasslands strongly depend on the regular removal of aboveground biomass by agricultural land use, mostly grazing or mowing or a combination of both. These specific management schemes have strong influence on plant diversity and vegetation composition, depending on their particular characteristics and their intensity. For example, the presence or absence of fertilization will favour some species over others, changing plant communities accordingly. Additionally, the farmer’s choice of a specific management scheme will also depend on the abiotic site conditions. This leads to a complex set of associated factors potentially affecting the structure and diversity of grasslands.
In this study, we compiled a unique dataset of 169 differently managed grasslands (in total 202 plots), which were sampled in five regions across Germany. For each plot, we documented management characteristics, measured plant diversity and functional group composition, recorded endangered species according to red lists, and calculated Ellenberg indicator values. We assessed patterns in vegetation composition and diversity in relation to the particular management scheme, which was categorized as meadow, meadow with autumn or winter grazing (with mowing as predominant management), mown pasture (where mowing and grazing are used at roughly equal intensity), seasonal pasture (with grazing as predominant management) and year-round pasture.
Our study showed that grasslands of different management schemes significantly differed in diversity, structure and functional composition. However, it also became obvious that vegetation composition was not strictly distinguished by management alone. Local and regional characteristics such as soil conditions, size of the grassland species pool or land-use history, often played a more prominent role than land use alone. Assumingly, the interplay of those local and regional characteristics with the proportion of grazing and mowing at a particular site inhibit clear differences among our predefined management schemes. Nevertheless, species richness was the lowest in year-round pastures, moderate in meadows and highest in seasonal pastures. In contrast, year-round pastures harboured the highest mean numbers of endangered species. The dependency of a certain management scheme on site-specific environmental factors such as soil fertility, further complicated the clear separation of management effects from those of the environmental background. In summary, modern grassland management strongly shaped grassland vegetation, but today’s combination of different management practices complicated the assessment of specific land-use effects on plant diversity. Thus, neither mowing nor grazing turned out to be “the one and only” management for nature conservation. Although our results challenge long-term prognoses for future vegetation development under modern grassland management, we clearly showed that low-intensity management and the absence of fertilization promoted plant diversity, with higher values in pastures compared to meadows and mown pastures.
GrassVeg.DE – die neue kollaborative Vegetationsdatenbank für alle Offenlandhabitate Deutschlands
(2017)
Der Bericht stellt die neue kollaborative Vegetationsdatenbank GrassVeg.DE (EU-DE-020; http://bit.ly/2qgX208) vor, die Vegetationsaufnahmen von Grasländern und anderen nicht-aquatischen Offenlandhabitaten Deutschlands sammelt, um sie national und international für die vegetationsökologische Forschung zur Verfügung zu stellen. GrassVeg.DE trägt die Daten zum European Vegetation Archive (EVA) und künftig auch zur globalen Vegetationsdatenbank „sPlot“ bei. Datenlieferanten von GrassVeg.DE behalten volle Verfügungsgewalt über ihre Daten und werden Mitglied des GrassVeg.DE-Konsortiums. Dadurch profitieren sie durch Co-Autorenschaften und Zitate von ihren Beiträgen und erlangen zugleich die Möglichkeit, selbst Projekte zu beantragen, die GrassVeg.DE- oder EVA-Daten nutzen. Die schnell wachsende GrassVeg.DE-Datenbank umfasste im Juli 2017 3.181 Vegetationsaufnahmen aus acht deutschen Bundesländern. Perspektivisch kann GrassVeg.DE dazu beitragen, eine konsistente Neuklassifikation der Graslandvegetationstypen Deutschlands im Rahmen der Synopsis der Pflanzengesellschaften Deutschlands zu ermöglichen. Wir schließen den Beitrag mit einem Aufruf, eigene und aus der Literatur digitalisierte Vegetationsaufnahmen zu GrassVeg.DE beizutragen.
Bromus racemosus L. is a rather rare grass species of moist meadows. It has strongly decreased in the course of the 20th century due to intensification of agricultural grassland management, and is therefore included in Red Lists of several European countries. Its winter annual life-cycle is remarkable for a species of permanent grasslands.
The aim of this study is to determine the habitat preference and optimal management of B. racemosus in the Netherlands and surrounding countries. Vegetation, soil and hydrological data from 28 sites in the Netherlands have been compared with B. racemosus cover, and with vegetation data from surrounding countries. The results indicate that B. racemosus is characteristic of Molinio-Arrhenatheretea meadows with good mineralisation and aftermath grazing. The optimum lies in grasslands of the alliance Alopecurion pratensis (Deschampsion cespitosae), but the species ranges from wetter Calthion palustris meadows to drier Arrhenatherion elatioris and Cynosurion cristati grasslands. It prefers intermediate nutrient levels and hydrological conditions (mesic sites), but within this range the highest cover is found in relatively nutrient rich and dry sites. Because of the absence of a seedbank and a low dispersal capability, B. racemosus is vulnerable to changes in grassland management. A management of mowing after 15 June and aftermath grazing is most suitable, since it enables fruit ripening and the maintenance of an open sward, needed for germination and development. The risk of extinction is likely to be higher in flat polders than in floodplain sites with natural relief, where the species may shift between belts in different years.