Tall-helophyte bed

Habitat description Communities of tall helophytes characteristically occupy a zone from shallow water to upper parts of the geolittoral belt along lakes and rivers. Further they are found in nutrient-rich terrestrial sites on waterlogged ground. In marshes and large lakes tall helophytes, such as Phragmites australis or Typha angustifolia, together with other emergent herbs (e.g. Thelypteris palustris) can overgrow accumulations of plant residues and form with their rhizomes and roots floating carpets and islets on the water surface. This habitat often represents the shore component of the habitat types C1.1a, C1.1b, C1.2a, C1.2b and C1.4 and therefore is in contact with them. The habitat includes wide and dense stands along eutrophic water bodies, as well as tall-helophyte stands occurring as wide belts along larger oligo- and mesotrophic lakes. These communities have poor water exchange with the open water area, and show clear accumulation of organic material. Tall helophytes include grasses (Phragmites australis, Glyceria maxima, Scholochloa festucacea), bulrushes (Schoenoplectus spp., Bolboschoenus spp.), cattails (Typha spp.), horsetail (Equisetum fluviatile), often accompanied by some broad-leaved emergent herbs (Rumex hydrolapathum, Cicuta virosa, etc.).

Reed bed vegetation belongs to the most productive European plant communities in terms of annual production of biomass. Shoot height is often 2-3 m, sometimes much higher. Because of competitive ability of tall helophytes, their stands are species-poor and often dominated by one species or by a few co-dominants. Main determinants for dominant species are substratum, water depth, duration of flooding anoxic periods, herbivory and human influence. Dominants grow in vigorous clones, and chance may play an important role in the arrival and establishment of potential dominants. Cover and composition of understorey vary according to the trophic state, substratum, succession stage, and disturbance (grazing, mowing, water level fluctuations, eutrophication, in the north also ice erosion). Grasses and herbs dominate in understorey, aquatic plants and shore mosses can occur, but are usually not abundant. An exception form initial phases towards mire succession, in which mosses may have a high cover.

Besides growing in the littoral zone of natural standing waters, reed beds grow also in anthropogenic standing water, like canals, stagnant dykes and reservoirs. Further, they are abundant alongside running waters in wetter parts of flood plains, and in rivers and streams. Both organic and mineral soils are colonized. In the northern boreal region helophyte stands are sparse and low due to the harsh climate and frozen soil, in arctic in alpine area they are lacking.

Also reed bed stands along brackish to freshwater coastal waters are included in this habitat, like those on the shores of the Baltic Sea and Black Sea or reed beds in the freshwater influenced parts of estuaries along the Atlantic and Mediterranean coasts. As their functioning and species composition may somewhat differ from more inland stands, these coastal examples may be considered as a separate subtype of habitat C5.1a.

Reed bed vegetation has been influenced strongly by human activities. Earlier helophyte stands were largely grazed and mowed, resulting in lower vegetation. Eutrophication and cessation of shore grazing has led in many places to increase of reed beds and their density but with a higher abundance of nitrophilous species. Excessive nitrogen and prolonged anoxic condition of the sediments have in some cases caused dying of reed beds. Reed beds are also impacted by regulation of water levels, construction activities, clearing of agricultural land, boating and other recreational activities. Losses of reed beds are locally caused by herbivory (coypu, muskrats).

Indicators of good quality:

• Reed beds with natural hydrology and water and substrate chemistry
• Typical structure of vegetation and natural species pool (species poor stands)
• Anthropogenic impacts low in terms of construction activities, eutrophication, drainage etc.
• Natural density of helophyte stands, not enhanced biomass or density due to eutrophication
• Absence of invasive alien species (also Glyceria maxima in the northern part of its range)
• No or low abundance of ruderal and nitrophilus (tall-herb) species (Urtica dioica, Calystegia sepium, Bidens spp., Chenopodium spp., Amaranthus spp.)
• No or low abundance of shrubs and climbing plants (e.g. Salix spp., Populus spp., Sambucus nigra, Vitis vinifera, Humulus lupulus)
• Low cover of tall species from drier habitats (e.g. Cirsium spp., Galega officinalis, Eupatorium cannabinum, Sambucus ebulus)
• Presence of characteristic breeding birds
• Presence of characteristic insect fauna

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats