Included here is the eastern edge of the Central Massif, the western edge of the Lorraine Plateau and the Massif of the Ardennes, the eastern shores of the Jutland Peninsula and southeastern shores of Norway. Its northern limit extends to the northern shores of the Gulf of Finland, the western shores of the Karelian Isthmus, and the entire western shore of Estonia.  Further on, the border moves south to the west of Riga, cuts through Latvia, passes south of Vilnius, turns towards the Belovezh Forest and west to Lvov. It then passes south of the Dniester River and proceeds along the Prut River to the lower Danube Lowlands.

Central European Black Alder-Ash Swamp Woodlands

Contrary to popular belief woodlands in which black alder (Alnus glutinosa) forms a major component are not restricted floodplains but can extend outside stream and river valley systems where reasonably wet condition prevail. For example, the Spree Forest (Spreewald), a Biosphere Reserve southeast of Berlin and probably the most important alder woodland in Central Europe, extends for some 48000 ha over marshy land. The majority of black alder woods in Central Europe are regarded as forms of the black alder – ash (Fraxinus excelsior) association. In the upper Spreewald the main tree layer is dominated by Alnus glutinosa and Fraxinus excelsior together with Acer pseudoplatanus, Prunus padus, Quercus robur, Tilia cordata and Ulmus laevis. Typical shrubs include Euonymus europaeus, Frangula alnus, Humulus lupulus, Ribes nigrum, R. rubrum, Rubus idaeus, Salix cinerea, S. pentandra and Sambucus nigra. The surprisingly rich herb layer may include depending on degree of wetness species such as Lamium maculatum, Lysimachia thyrsiflora, Peucedanum palustre, Stachys palustris, Thelypteris palustris, etc and a variety of grasses and sedges. Black alder-ash woodland also forms a significant component of the primeval Bialowieza Forest in Poland and Belarus. Here they are a common feature of streamsides subject to periodic inundation but often give way to ash-elm forest where the ground water is lower. The best example can be seen along the course of the Orlowka Stream. In addition to black alder and ash, spruce is also always present here as a canopy or undergrowth tree. Other undergrowth species include Corylus avellana, Euonymus europaea, Prunus padus, Ribes nugrum and Ribes rubrum as well as alder and ash. Composition and structure of the exuberant herb layer displays major seasonal variation, although contribution from spring geophytes is mainly limited to mass displays of Anemone nemorosa. In summer tall perennials up to a metre tall predominate with species like Chaerophyllum hirsutum, Cirsium oleraceum, Filipendula ulmaria and Urtica dioica. Below these are tiers of other species such as Caltha palustre, C. cornuta, Chrysosplenium alternifolium, Equisetum sylvaticum, Hepatica nobilis and Lamiastrum galeobdolon.

Central European Inundation Grassland

One of the best and most undisturbed examples of central European inundation grasslands can be found on the floodplain of the Morava River separating Austria and Slovakia. After the Second World War it became part of the Iron Curtain border zone and as a result was almost completely closed to any human activity. The area comprises several grassland types including ones dominated or characterized by Carex acuta, Glycera maxima, Phragmites australis, Potentilla anserina, Rorippa amphibia and Scirpus lacustris, but the most extensive inundation meadows are descibed as a Alopecurus pratensis – Cnidium dubium community. These are typically inundated at the start of the growing season but as the summer progresses the surface soil gradually dries out. Nevertheless, these have the highest species diversity of all the inundation communities. In addition to Alopecurus pratensis the main grasses include Agrostis stolonifera, Elymus repens and Poa angustifolia, while other characteristic species include Carex praecox, Clematis integrifolia, Cnidium dubium, Galium boreale, Gratiola officinalis, Inula salicina, Serratula tinctoria and Veronica longifolia. Geophytes include Allium angulosum and Iris sibirica. In the most elevated areas, Festuca nigrescens becomes the main character species. Inundation in these areas is often very short and irregular. Other characteristic species include Colchicum autumnalis, Galium verum, Ranunculus auricomus, Sanguisorba officinalis and Serratula tinctoria. In spring the white flowers of Ornithogallum orthophyllum become a feature. Less common species typically include taxa from drier meadows such as Centaurea jacea and Leucanthemum vulgare. Overall these inundation grasslands support some 540-plant species from a variety of different phytogeographical zones. For example, there are boreal (continental) species such as Barbarea stricta, Inula salicina and Veronica longifolia; subcontinental species such as Carex melanostachya, Plantago altissima and Viola pumila; and euroasiatic species such as Cnidium dubium and Erysimum diffusum. Also present are Pannonian endemics or near endemics like Dianthus pontederae (Caryophyllaceae) and Lathyrus pannonicus subsp. pannonicus (Fabaceae). 

References

Banásová, V., Jarolímek, I. Otahelová, H. & Zaliberová, M. 1998. Inundation grasslands of the Morava River, Slovakia: plant communities and factors affecting biodiversity. In: European Wet Grasslands – Biodiversity, Management and Restoration. Eds. C. B. Joyce and P. M. Wade. John Wiley & Sons.

Botta-Dukát, Z., Chytry, M., Hájková, P. & Havlová, M. 2005. Vegetation of lowland wet meadows along a climatic continentality gradient in Central Europe. Preslia, Praha, 77: 89-111.

Casazza, G., Zappa, E., Mariotti, M. G., Médail, F. & Minuto, L. 2007. Ecological and historical factors affecting distribution pattern and richness of endemic plant species: the case of the Maritime and Ligurian Alps hotspot. Diversity and Distribution, 2007: 1-12.

Ellenberg, H. 1988. Vegetation Ecology of Central Europe. Cambridge University Press.

Hérault, B. & Thoen, D. 2008. Diversity of plant assemblages in isolated depressional wetlands from Central-Western Europe. Biodiversity and Conservation, 17: 2169-2183.

Polunin, O. & Walters, M. 1985. A guide to the vegetation of Britain and Europe. Oxford University Press.

Schnittler, M. & Gunther, K. F. 1999. Central European vascular plants requiring priority conservation measures – an analysis from national Red Lists and distribution maps. Biodiversity and Conservation, 8: 891-925.

Szafer, W. 1966. The Vegetation of Poland. Pergamon Press.