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Galio-Urticetea
Aims: To describe the compositional and ecological diversity of Mulgedio-Aconitetea communities in the Sudetes Mts. and their foothills. Study area: The Sudetes Mts. (Southwestern Poland). Methods: A total of 399 vegetation relevés from own field studies and the literature were sorted into groups that match the higher syntaxa of the EuroVegChecklist and associations described in the literature. Diagnostic species of the so delimited associations were determined with the phi-coefficient of association, and maps of the associations produced. Direct ordination methods were applied to identify the main environmental gradients shaping the plant communities. Results: We distinguished nine associations, belonging to four alliances: submontane and colline communities (Petasition officinalis: Geranio phaei-Urticetum dioicae, Petasitetum hybridi, Chaerophyllo hirsuti-Petasitetum albi, Prenanthetum purpureae), upper montane nitrophilous communities (Rumicion alpini: Rumicetum alpini); subalpine communities with a dominance of graminoids and ferns (Calamagrostion villosae: Poo chaixii-Deschampsietum cespitosae, Crepido conyzifoliae-Calamagrostietum villosae, Athyrietum filicis-feminae) and subalpine tall-herb communities (Adenostylion alliariae: Cicerbitetum alpinae). Altitude, light availability, and bedrock type, which determines nutrient availability and soil reaction, played an important role in differentiating the studied communities. Conclusions: For convenience, we placed the four alliances in four separate orders as in the EuroVegChecklist. The fact that our ordination diagram separated only two main groups suggests the need of further research in this matter. Taxonomic reference: Euro+Med (2006-) for vascular plants. Syntaxonomic reference: Higher syntaxa follow Mucina et al. (2016). Abbreviations: db-RDA = distance-based redundancy analysis; EIV = Ellenberg indicator value; pANOVA = permutational analysis of variance; PCoA = principal coordinates analysis.
The high diversity of ruderal vegetation in urban environments is well known. Although it has been a subject of numerous studies in Serbia, in recent years it has been slightly overlooked, although, due to the dynamics of ruderal habitats, constant research is required. We investigated ruderal vegetation in 20 cities across Serbia during a period of 5 years. Most of the relevés were collected during the summer months, and within 712 relevés, 422 taxa were recorded. Results of the cluster analyses and identified diagnostic species revealed 26 plant communities, of which nine are dominated or co-dominated by aliens. The relevés can be grouped into six ecologically well-differentiated major vegetation groups. Our study revealed the ruderal communities which are the most widespread in urban environments in Serbia. Additionally, some communities were registered for the first time in the country.
Chelidonium majus is a typical species of old settlements. Although being one of the most widespread plants in Central Europe, its germination biology is hardly known. Information on its floristic status are unclear too. We have checked therefore critically the information on its morphology and living mode. Its germination was investigated under different conditions. The monthly germination rate shows a clear optimum in spring time (March till June with a maximum in April.). This corresponds to the germination behaviour in nature. The nitrophilous behaviour of Chelidonium majus was proven by our experiments: its germination was the most successful in 0,001 mol KNO3 solution, the highest at room temperature. The lowest germination rate was found at 10°C. We carried out also competition tests with plants which are often associated with Chelidonium majus: Geranium robertianum, Aegopodium podagraria, Alliaria petiolata and Urtica dioica. As result we can say that Chelidonium majus is a relatively week competitor. Especially when competing against Urtica dioica and Alliaria petiolata a clear depression of biomass and growing height has to be noted, whereas Geranium robertianum was the weakest competitor as expected. All mapping results in Central Europe indicate a strong liaison to human settlements, seldom findings at forest edges are not in contradiction but have to be associated with rubbish or garden waste disposals. Chelidonium majus is myrmecochorous, obviously an effective long distance dispersal is missing. The high nitrophily was presumably a spreading barrier in former times where nitrogen rich places outside of settlements have been rare. Based on own field investigations and on checking of the literature we assume that there was no growing place in natural landscape for Chelidonium majus before human settlement started. Following we post the hypothesis: Chelidonium majus is an archeophyt in Germany. The genus Chelidonium is divided into three taxa very similar to each other. It appears within a huge area between Western Europe and Eastern Asia: Chelidonium majus subsp. majus is the European taxon, Cheli-donium majus subsp. grandiflorum is the Central Siberian-Chinese taxon, Chelidonium majus subsp. asiaticum is the Korean-Manchurian taxon. There is a gap of distribution in the area of Kazakhstan and the adjoining Western Siberia between the 60. and the 80. degree of longitude, which actually is not explainable. A survey of the association of Chelidonium majus in Central Europe was carried out having the focus on the diversity of the species combination but not on the syntaxonomy. As a noteworthy however surprising result we found that Chelidonium majus is the most frequently growing plant on old walls in Germany.
1. This account presents information on all aspects of the biology of Robinia pseudoacacia L. that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, and history and conservation.
2. Robinia pseudoacacia, false acacia or black locust, is a deciduous, broad-leaved tree native to North America. The medium-sized, fast-growing tree is armed with spines, and extensively suckering. It has become naturalized in grassland, semi-natural woodlands and urban habitats. The tree is common in the south of the British Isles and in many other regions of Europe.
3. Robinia pseudoacacia is a light-demanding pioneer species, which occurs primarily in disturbed sites on fertile to poor soils. The tree does not tolerate wet or compacted soils. In contrast to its native range, where it rapidly colonizes forest gaps and is replaced after 15–30 years by more competitive tree species, populations in the secondary range can persist for a longer time, probably due to release from natural enemies.
4. Robinia pseudoacacia reproduces sexually, and asexually by underground runners. Disturbance favours clonal growth and leads to an increase in the number of ramets. Mechanical stem damage and fires also lead to increased clonal recruitment.
5. The tree benefits from di-nitrogen fixation associated with symbiotic rhizobia in root nodules. Estimated symbiotic nitrogen fixation rates range widely from 23 to 300 kg ha−1 year−1. The nitrogen becomes available to other plants mainly by the rapid decay of nitrogen-rich leaves.
6. Robinia pseudoacacia is host to a wide range of fungi both in the native and introduced ranges. Megaherbivores are of minor significance in Europe but browsing by ungulates occurs in the native range. Among insects, the North American black locust gall midge (Obolodiplosis robiniae) is specific to Robinia and is spreading rapidly throughout Europe.
7. In parts of Europe, Robinia pseudoacacia is considered an invasive non-indigenous plant and the tree is controlled. Negative impacts include shading and changes of soil conditions as a result of nitrogen fixation.
Die Vorkommen der Reynoutria-Populationen im Aachener Stadtwald wurden pflanzensoziologisch untersucht. In Übereinstimmung mit den Angaben in der Literatur (Oberdörfer 1979, S. 327 und 1983, S. 268 ff.) finden sich die Reynoutria-Sippen häufig in Convolvuletalia-Gesellschaften. Darüber hinaus treten sie aber auch im ruderal beeinflußten Arrhenatheretum elatioris, im Vorwald (Sambucetum race- mosae) und im Buchenwald (Luzulo-Fagetum) auf. Dabei bevorzugen sie kalkarme, mehr oder weniger durchlässige Böden mit guter Wasserführung. Ökologisch differieren die Sippen anscheinend nur geringfügig. Nur bezüglich der Schattentoleranz erweist sich R. japonica den anderen Sippen gegenüber im Vorteil.
Typifies the ruderal communities on the basis of the prevailing life-forms, their seasonal dynamics and synphenology, and their position within the successional series. A classification of the anthropogenic habitats of the ruderal communities in the region is also presented. -from Author
