28E5

E. Herbaceous communities and communities of lichens and mosses

Lowland riverside tall-herb communities

Relationships with habitat classifications. EUNIS: E5.41 Screens or veils of perennial tall herbs lining watercourses, E5.423 Continental tall-herb communities, E5.43 Shady woodland edge fringes: PAL. CLASS.: 37.71 Watercourse veils, 37.72 Shady woodland edge fringes, 37.13 Continental tall-herb communities; HD 92/43: 6430 Hydrophilous tall herb fringe communities of plains and of mountain to alpine levels.

Conservation status. BDA, HD.

Category. Endangered [EN - A1, 2 C1 D2 E2 F2 G1 H1 I J L2].

General characteristics. Plant communities that are called “tall grasses” or “altoherbosa” are widely distributed along the rivers throughout the country. They are different mixed coenoses with 1–1,5 m, sometimes even 2 m, high herbs. Usually they cover narrow stripes (up to 2–3 meters, often narrower) along running waters and on the wet banks. Typical hygrophytes and hygromesophytes prevail. Most of these species can grow both in the water (shallow water 0,10–0,20 m high) and on over-wet soils. The vegetative optimum is in the second half of the summer, when the rivers are low and the plants cover the mud and wet gravel alongside. The species composition is very diverse and depends both on the altitude and the composition of the surrounding communities. They can be classified in three main subtypes corresponding to different codes from the EUNIS Classification.

1. Screens or veils of perennial tall herbs lining watercourses (E5.41). These are communities that make narrow strips in open places beside running water bodies in the lowlands (up to 1000–1200 m alt.), mostly on gravel or clay ground. The soils are rich and moderately nitriphied. Typical species are Althaea officinalis, Eupatorium cannabinum, Angelica sylvestris, Berula erecta, Bidens cernua, Calystegia sepium, Dipsacus laciniatus, Echinochloa crus-galli, Epilobium hirsutum, Equisetum ramosissimum, Humulus lupulus, Leersia oryzoides, Leonurus cardiaca, Lycopus europaeus, Lythrum salicaria, Mentha aquatica, M. longifolia, Nepeta cataria, Polypogon viridis, Rubus caesius, Scrophularia umbrosa, Stachys palustris, and Urtica dioica.The participation of Angelica pancicii, Caltha palustris, Chaerophyllum hirsutum, Filipendula ulmaria, Inula helenium, and Petasites hybridus increases at the mountain foothills.

2. Continental tall-herb communities of humid meadows along the Danube (E5.423). This habitat subtype is typical for the Danube. It covers strips along the river, meadows in the alluvial willow-poplar woods, and the periphery of swamps. Very often these communities are of secondary origin, and many ruderals and neophytes also occur. The soil is eutrophic and polluted with nitrates as a result of the river floods. The coenoses in the flooded meadows in the river-side lowlands that are closest to the primary ones belong to the alliance Veronico longifoliae-Lysimachion vulgaris from the class Molinio-Arrhenateretea. The communities dominated by Euphorbia lucida are the most typical ones along the Danube, and often reach approx. 2 m in height. Many medium-high herbs participate such asArtemisia annua, Glycyrrhiza echinata, Iris pseudacorus, Lysimachia vulgaris, Lythrum salicaria, L. virgatum,Pseudolysimachion longifolium (= Veronica longifolia), P. spurium (= Veronica spuria), Rubus caesius, Senecio paludosus, Stachys palustris, Tanacetum vulgare, and Urtica dioica.In the composition of these tall-grass communities some grass species also participate such as Calamagrostis epigejos, Elymus repens, Phalaris arundinacea, and Polypogon viridis.Unespectedly, in the continental flooded meadows along the Danube with which the tall-grass communities often make complexes the grasses are not dominants but participate in the communities sporadically. The role of the invasive neophytes in the natural coenoses increased in the last few years. This refets also to the tall-grass communities. Such neophytes are Amorpha fruticosa, Bidens frondosa, Echinocystis lobata, Erigeron annuus, Sicyos angulatus etc. In many places in the lowlands along the Danube these coenoses have a secondary origin in abandoned arable lands, in the periphery of swamps and along amelioration canals when the soil is wet enough and polluted with nitrates.

3. Shady woodland edge fringes (E5.43). These communities belong to the semi-ruderal syntaxa from class Galio-Urticetea,alliance Aegopodion podagrariae (order Lamio albi-Chenopodietalia boni-henrici and order Convolvuletalia sepium). They form strips along streams and small rivers in shadowy places, in humid ravines and lowlands with high air and soil humidity. They are most often composed of Aegopodium podagraria, Alliaria petiolata, Anthriscus sylvestris, Carex pendula, Chaerophyllum hirsutum, Chelidonium majus, Circaea lutetiana, Cucubalus baccifer, Galeopsis speciosa, Galium aparine, Geranium phaeum, G. robertianum, Geum urbanum, Glechoma hederacea, Heracleum sibiricum, Impatiens noli-tangere, Inula helenium, Lamium maculatum, Lapsana communis, Myosoton aquaticum, Parietaria erecta (= Parietaria officinalis), Physalis alkekengi, Stachys sylvatica, Silene dioica, Smyrnium perfoliatum, Telekia speciosa, and Viola odorata. Equisetum telmateia makes monodominant coenoses on limestone. This habitat subtype is typical for the mountain foothills and low mountains in the belt of the mesophilic forests (between 800 and 1300 m alt.), but sporadically they can also occur in the lowlands (humid ravines).

Characteristic taxa.

Distribution in Bulgaria. Throughout Bulgaria, along all rivers in the lowlands, and foothills of the mountains, up to 1200–1300 m alt.

Conservation importance. The coenoses of this habitat type are very diverse. Although most of the species in the coenoses are widely distributed and even ruderals some species of conservation significance also occur, such as Euphorbia lucida.

Threats. Hydro-ameliorative activities along the rivers – building dykes, consolidation of river banks, redirection of river beds, draining of the flooded areas and swamps, ploughing, intensive cultivation in the neighbouring land, general climate aridisation, poplar plantations in the lowlands, felling in the riverine forests, extraction of gravel and sand from the river beds, water and soil pollution, natural erosion and accumulation of river deposits, invasive species that change the floristic composition and the ecological structure of the tall-grass communities, especially along the Danube.

Conservation measures taken. The habitat is included in Annex № 1 from the Biodiversity Act. Some of the localities are within the borders of Balgarka, Strandzha, Russenski Lom, Vitosha and Persina Nature Parks, Kalimok-Brashlen Protected Site, Chernelka and Studenetz Nature Monuments and in sites of the European Ecological Network NATURA 2000.

Conservation measures needed. Termination of the hydro-ameliorative activities and of exploitation of gravel and sand from the rivers in Bulgaria, monitoring of the invasive species that participate in the phytocoenoses.

References. Stojanov 1948; Tzonev 2009.

Authors: Vladimir Valchev, Valeri Georgiev, Rossen Tzonev


Lowland riverside tall-herb communities (distribution map)