Typha minima
Dwarf cattail ( Typha minima), fruit stand
The dwarf cattail ( Typha minima) is a very rare to the family of cattail plants ( Typhaceae ) belonging marsh plant. It is characterized by its nearly globular seed heads and often forms species-poor stands dominated in quiet bays and backwaters of rivers. In the course of river regulation of the past hundred years, the species experienced a dramatic decline and is now centrally and across Europe as the threat of extinction.
Description
The dwarf cattail is a 30 to 70, sometimes 140 cm high Hemikryptophyt and hydrophyte - a perennial, herbaceous plant with submerged overwintering buds. The vegetative propagation takes place over short 5 to 8 millimeters thick processes ( rhizomes), which grow up to 20 cm deep into the ground and then rise arching. The leaves are very narrow linear, blue-green and not shiny. You can reach up to 30 centimeters in length and 1 to 2 millimeters in width. There are only the leafy sterile shoots, stems on the flowers they are missing. These have only spreitenlose leaf sheaths. The leaf blades are semi-circular in cross-section, lower side distinctly arched and flat on top. They are filled with a spongy marrow. The leaf sheaths are open and slightly auriculate at the vaginal orifice.
The flowers are unisexual. The female flowers form an ovoid - globular, about 4 inches long, brownish black piston - in contrast to the other European Typha species with cylindrical piston. Furthermore located by a 0.5 to 3 inches long rung portion separated the male flowers, which are one to two times as long as the female piston. The female flowers have a stalked ovary, which is surrounded by a thick fringe of hair. The three individual stamens of the male flowers are surrounded by only a few hairs. The main flowering period of the species lasts from mid-April to June. In August, it may be a further flowering.
Distribution and location
The dwarf cattail is common in Europe and Asia. He has a strong disjoint area, which has large gaps. The distribution is limited to the major river systems of the Alps with the foothills of the Alps, the Apennine Peninsula, the Danube basin and the Balkans as well as the mountains of Central and Eastern Asia.
In the Alpine region, there are only a few small isolated occurrences in the Durance valley and in Haute-Savoie in France and in Graubünden in Switzerland. Furthermore, several in recent years artificially settled populations are present in the Valais. The formerly large populations in Germany are now all gone. In Austria, the species is also greatly reduced. Remnants of formerly large deposits still exist in Vorarlberg and Tyrol. These are today across the Alps and the largest populations.
He is a pioneer species large alpine floodplains. It grows on periodically flooded banks of slow-flowing, pure and cool waters. He settled preferably without vegetation newly created Backwater and peaceful meander of the main river bed with base-rich calcareous mostly, rich, sandy, silty and gravelly deposits ( Schwemmsandböden ). He is on the north side of the Alps along with the colorful horsetail ( Equisetum variegatum ) is a species-poor plant community ( association ), the so-called dwarf cattail Society ( Equiseto - Typhetum minimae Br Bl people in 1939). Secondary, the cattail plant colonize gravel pits with basic water supply and artificial Schwemmsandflächen.
Ecology
The light- loving plant can not tolerate shade. Your ecological focus is on low-nitrogen to nitrogen poorest, base- or lime-rich, drenched regularly flooded and air- poor soils. Pollination of flowers carried by the wind ( anemophily ). Spread is through airborne seeds ( Anemochorie ) but also effective by the drifting of Rhizombruchstücken and clods.
Through its rhizomes, the dwarf cattail spreads vegetatively quickly spread to the newly conquered sites. However, it is a little competitive pioneer and is just as quickly replaced in the course of Auensukzession back of höherwüchsigen plants such as sedge and reeds. Without sporadic floods, which cover the site with fresh mud or keep open the dwarf cattail is displaced within 10 to 50 years due to natural succession. The species can only survive as long as the natural Auendynamik is not disturbed and to create ever new suitable vegetation-free sites from the river.
In contrast to the other species of the genus in which the seeds leave the pericarp with prolonged contact with the water fall and germinate under water ( anaerobic), they remain with the dwarf cattail always in the pericarp and germinate in the air under aerobic conditions. Both fruits as well as young seedlings do not sink and then transported by water to the river bank, where they germinate on silt and fine sand and anchor their primary roots in the substrate. The germination rate of mature fruits is 90 %, but increases the germination rate decreases rapidly. After about a year the seeds do not germinate.
Threats and conservation
The dwarf cattail is central Europe threatened with extinction. It is part of the Bern Convention, the implementation is carried out mainly in the EC Birds Directive and the Habitats Directive. The Typha Society has been classified as priority habitat in Annex I of the Habitats Directive, should be taken to special measures for the conservation and development in the framework of the European system of protected areas Natura 2000. In Germany, the species also as threatened with extinction applies and is listed in the Red List of endangered ferns and flowering plants ( hazard category 1). In Austria, the dwarf cattail is guided in the list of species in Austria endangered ferns and flowering plants. In Switzerland, the species is considered endangered.
The sources of risk are to be sought primarily in the development and regulation of rivers, and the failure Auendynamik. Furthermore, gravel mining, construction of roads, as well as groundwater and river bed reductions mentioned.