Common beach grass

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Common beach grass
Common beach grass (Ammophila arenaria)

Common beach grass ( Ammophila arenaria )

Systematics
Commelinids
Order : Poales (Poales)
Family : Sweet grasses (Poaceae)
Subfamily : Pooideae
Genre : Beach grass ( Ammophila )
Type : Common beach grass
Scientific name
Ammophila arenaria
( L. ) Link
Illustration of the common beach grass (left in the picture)
Flowering panicle
Lemmas
Edge of a white dune with exposed beach hay roots
White dune overgrown with common beach grass
Due to the constant transfer of sand, the common beach grass is forced to grow higher and higher. Only the weakening of the beach grass by soil organisms brings the process to a standstill and ultimately determines the height of the dunes.
Roll sheet
Fragmentary training in an inland dune

The Ordinary beach grass ( Ammophila arenaria (L.) Link ; Syn: Calamagrostis arenaria (L.) Roth ) - also known as Common beach grass , sand tube , Sandhalm , sea oats or helmet ( Low German called) - is the family of the sweet grasses (Poaceae) associated Pioneer plant .

On coasts and islands, grass plays a special role in the structure and stability of dunes . It is significantly involved in the formation of the white dunes, which are up to 25 meters high. Furthermore, due to its extensive root system, the common beach grass is planted in the context of coastal protection measures as erosion protection for the fortification of edge dunes, now more rarely on inland dunes and drifting sand fields .

features

The common beach grass is a strong, upright growing grass that overwintered green and reached heights of up to 120 cm. It is a rhizome geophyte and forms clumps , which in turn can develop dense lawns through richly branched underground shoots . The species forms both horizontal and vertical rhizomes . The young pithy rhizomes are whitish and have yellowish-white, dead scale leaves. Aging rhizomes are hollow and turn yellow to brown in color. The young roots are also white and fleshy, while they become lignified and brown as they age. At each of the many dormant nodes , four roots form, which in turn can branch out richly.

The 30 to 60 cm long, stiff, blue-green leaves are usually rolled up and then measure around 1 to 3 mm in diameter. When spread out, they reach a width of 4 to 6 mm. They are pointed, smooth and glabrous, but finely hairy on the upper side along the leaf veins . The underside is also smooth and bare. The edges of the smooth leaf sheaths overlap. The ligules are strikingly large, up to 25 to 35 mm in length. They are split from top to bottom.

The inflorescences of the common beach oat are compact, foxtail-like panicles . They are up to 15 cm long, are twisted on all sides and are always drawn together. The spikelets are single-flowered and up to 16 mm long. The two glumes are lanceolate, pointed and rough, the lower one is single-veined, the upper three- to five-veined. They are about as long as the spikelet. The lemmas are also pointed lanceolate and have a double point. They are 5 to 7 cores and 8 to 12 mm long. They have hair 3 to 5 mm long at the base. The central vein ends just below the husk edge in a protruding awning tip that is 0.2 to 0.8 mm long. The beach grass blooms from June to July. The caryopses are three to 3.5 mm long.

The number of chromosomes is 2n = 28.

distribution

The common beach grass is an originally European and North African species. It occurs here on all coasts. Ammophila arenaria subsp. arenaria dominates the coasts of northwestern Europe, Ammophila arenaria subsp. arundinacea the Mediterranean .

At the end of the 19th century, beach grass was introduced and planted in Australia , New Zealand , North America (1868, San Francisco) and Japan for the purpose of dune fortifications. Beach grass also grows in South Africa , the Falkland Islands , Argentina and Chile , often as a result of the colonization of British and Spanish colonies .

Habitat and Ecology

The common beach grass is a pioneer plant that depends on moving sand . The leaves and stalks break the force of the wind and force the blown sand to settle. Its roots bind the sand. In this way, the grass plays a key role in the formation of the white dunes , which are up to 25 meters high . It is the characteristic of the plant community of the so-called beach rye-beach grass lawn (Elymo-Ammophiletum Br.-Bl. et De Leeuw 1936) and is associated with the beach rye ( Leymus arenarius ).

Location requirements

The common beach grass prefers an oceanic climate near the sea. It can only grow on substrates that contain less than 1% table salt . Studies have shown that the plant dies at concentrations as low as 1.5%. Therefore it only grows where its place of growth cannot be reached by the lake water. It is a full-light plant and only grows in fully sunny locations that have a moderate nitrogen supply. He is dependent on regular transmission. Without this constant supply of sand, the beach grass dies. The blown sand is desalinated by precipitation and has a fertilizing effect. It supplies the plant with phosphorus , potassium and calcium carbonate . Rotting organic material represents an additional source of nitrogen. If there is no regular supply, a nutrient deficiency occurs. The plant is absent on wet and often drying soils as well as on strongly acidic soils. The ecological focus of the beach oaf is in pH ranges between five and nine. Its ecological behavior can accordingly be classified as follows on the basis of the pointer values ​​according to Ellenberg , which roughly reflect the above-mentioned location factors for Central Europe: light index = 9 (full light plant), temperature index = 6 (moderate warmth to warmth indicator), continental index = 3 (oceanic to suboceanic) , Moisture number = 4 (dryness to freshness indicator), reaction number (R = pH range) = 7 (weak acid to weak base indicator), nitrogen number = 5 (moderately nitrogen-rich locations), salt number = 1 (occasionally on salty soils).

Propagation Mechanisms

The spread of the fruits ( generative reproduction ) of the wind-pollinated plants only plays a subordinate role ( wind and Velcro spread ). The seedlings can only establish themselves in very protected areas. Even a layer of sand of only 1 cm can prevent the germination of the caryopses.

The beach grass spreads primarily vegetatively . If it is spilled by the sand that is caught between its stalks after a storm, it quickly grows through the sand and forms additional roots in the new sand layer. He builds up the white dunes floor by floor. The beach grass is able to grow through up to 1 m of sand per year. The main root horizon is about one meter below the surface, sometimes up to two meters. The root system of a single plant can root through a radius of five meters in several levels and, including the fine roots, can reach a length of several kilometers. The vertical spread takes place along the vertical rhizome, on which the above-ground shoots, which stand together in clusters, are formed. Beach grass does not completely stop growing even in winter. The plant is also able to develop and regenerate from rhizome fragments. The plants of a generation can live up to 100 years.

Adjustments and competitive strategy

The beach grass with hard rolled leaves - similar to the dune couch grass ( Elymus athericus ) - and additionally highly reflective undersides of the leaves is well adapted to the physiological dryness of its growing areas due to wind and the sandy soil that is highly permeable to precipitation . This scleromorphic structure of the leaves offers greater resistance to water loss through transpiration . The leaves have a thick cuticle and epidermis . They are stiffened and therefore very hard. This also protects the plant against wind grinding caused by the sharp-edged grains of sand blowing away.

The beach grass is a so-called competitive stress strategist (CS), i. H. in poor living conditions ( stress ), the vigorous pioneer has an advantage over other plants (competitors) which dominate in more favorable locations. Potential competitors who are not adapted to these extreme site conditions are eliminated in the windy sand. In fixed dunes, however, the beach grass is quickly displaced by interspecific competition.

Roundworms (nematodes) and fungi

In the moving sand of the white dunes, the plants are usually vital. In the dormant sand of the gray and brown dunes, on the other hand, it can often be observed that the plants do not bloom and do not form seeds. This is possibly due to the interaction of roundworms (nematodes) and fungi that attack the roots. The fungus hyphae can penetrate through the feeding points of parasitic roundworms, especially of the genus Tylenchorhynchus . As a result, the plants die off due to a lack of nutrients and water. In the moving sand, on the other hand, the beach grass escapes the harmful effects of the plant pathogenic and other soil organisms, the population of which is apparently the same at the locations. The harmful effect is associated with a decrease in fungi that have a beneficial effect on root growth, so-called mycorrhiza , with increasing aging and acidification of the gray and brown dune locations. The balance between sand drift, the formation of biomass and the weakening of the beach oat by organisms that damage the root system ultimately limit the height of the white dunes to around 25 meters.

The beach grass as a food crop

The beach grass is the only food plant ( monophagy ) for the caterpillars of the beach grass white-veined owl ( Mythimna litoralis ). Furthermore, the grass for Küstensandzirpe ( Psammotettix maritimus ) and the beach grass-planthopper ( Gravesteiniella Boldi ) the only host plant. The beach grass is also food for a soft bug (Miridae), Trigonotylus psammaecolor , which sucks on the leaves and immature seeds. The eggs are laid in the ears.

Etymology, systematics and hybrids

The scientific name of the common beach oaf translates as "sandy sand friend". The generic name Ammophila comes from the Greek and means sand friend, from ámos = sand and philos = friend. The epithet arenaria is Latin and means "sandy". The beach grass does not belong to the genus oats ( Avena ), but to the genus Ammophila , but like this belongs to the tribe Aveneae.

The plant was first described in 1753 by the Swedish scientist Carl von Linné in his Species Plantarum as Arundo arenaria ( Basionym ). In 1827 the transfer to the genus Ammophila took place , thus renaming it to Ammophila arenaria by the German scientist and former director of the Botanical Garden Berlin , Heinrich Friedrich Link , in the Hortus regius botanicus Berolinensis , Volume 1, p. 105.

There are currently two subspecies:

  • Ammophila arenaria subsp. arenaria (Syn: Calamagrostis arenaria (L.) Roth subsp. arenaria ): It occurs in northern and western Europe.
  • Ammophila arenaria subsp. australis (Mabille) M. Laínz (Syn: Calamagrostis arenaria subsp. australis (Mabille) Asch. & Graebn. ): It occurs in the Canary Islands and from the Mediterranean region to Romania.

The North American Ammophila breviligulata Fern. In contrast to Ammophila arenaria, it has a shorter, truncated ligula (ligule) and is otherwise identical in terms of its characteristics and has therefore been regarded by some authors as a subspecies of the common beach oat and then Ammophila arenaria subsp. called breviligulata .

The common beach grass forms a sterile genus bastard by crossing with the land riding grass ( Calamagrostis epigeos ) , the Baltic beach grass ( Calammophila baltica , syn. Ammocalamagrostis baltica ), which is no less important for the consolidation of coastal locations. It can be distinguished from its parent species Ammophila arenaria by the loose, purple-colored and lanceolate panicles, the less rigid and often flat leaf blades, the lanceolate glumes and the longer hairs on the base of the lemmas and finally the smaller anthers. The hybrid populations also differ in their similarity to the parent species. The British populations are mostly more similar to common beach grass, while those on the Baltic Sea are more like land grass.

Common names

For the common beach grass there are or existed, in some cases only regionally, the other German-language trivial names : Halem ( Helgoland ), Hallem (Helgoland), Heelme ( Jutland ), Hellem ( Wangerooge ), Helm (Jutland and Norderney ), Helmd ( Jutland), Rotwettel (only refers to the root, Wangerooge), Sandhalm, Sandhawer ( Lower Weser ) and Strandhafer ( Mark Brandenburg ).

Importance and use

The particular importance of the common beach beach today lies primarily in its property of defining the sea-side edge dunes of the islands and the mainland and thus the protection against storm surges . Because of this protective function, these dunes are also referred to as “protective dunes” according to the Lower Saxony Dyke Act and are specifically planted with beach grass, which is taken from intact and healthy stocks. Entering protective dunes should only take place on designated paths, because the impact not only affects the sensitive seedlings, but also tramples the mature plants. The wind can blow the sand away unhindered, narrow gullies can blow out into gorges one meter deep and finally set entire dunes in motion, which ultimately results in the loss of their protective function.

In Central Europe were the Middle Ages through overuse many defined by the vegetation inland dunes Pleistocene origin back to shifting sand dunes. This ultimately led to a loss of arable land and settlements. The first beach grass plantings were therefore carried out inland in the 17th century. Most of the recent beach grass stocks in sand habitats are due to this.

Outside of its natural range, for example in North America and Australia, the common beach grass was introduced at the end of the 19th century specifically for the purpose of dune reinforcement. The plant spreads independently almost everywhere and is considered an invasive neophyte , because it is increasingly becoming a problem in many places due to its high dispersal and competitive power, as it displaces the native flora and changes the existing ecosystems . For example, common beach grass in Humboldt Bay (California) is specifically fought as part of a management plan.

In earlier centuries, the firm leaves of the beach grass were used to make cords and ropes, so-called reepen , and mats.

Sources and further information

Individual evidence

Most of the information in this article is taken from the sources given under Literature and Web Links; the following sources are also cited:

  1. ↑ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas. 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 , p. 255.
  2. ↑ K. Rieck: Vegetation-ecological studies of selected dune complexes on the East Frisian islands Baltrum, Langeoog, Spiekeroog and Wangerooge. Dissertation. University of Hanover, 2000. (PDF ; 5.6 MB)
  3. ^ E. Pernilla Brinkman, Johannes A. van Veen, Wim H. van der Putten: Endoparasitic nematodes reduce multiplication of ectoparasitic nematodes, but do not prevent growth reduction of Ammophila arenaria (L.) Link (marram grass) . Netherlands Institute of Ecology (NIOO-KNAW), Center for Terrestrial Ecology, Departments of Multitrophic and Plant-Microorganism Interactions, Heteren 2003. doi: 10.1016 / j.apsoil.2004.02.004 .
  4. ^ Catalog of the Lepidoptera of Belgium: Mythimna litoralis . ( Memento of December 7, 2008 in the Internet Archive )
  5. ↑ H. Nickel, R. Remane: List of species of cicadas in Germany, with information on nutrient plants, food breadth, life cycle, area and endangerment (Hemiptera, Fulgoromorpha et Cicadomorpha). In: Contributions to the cicada. 5/2002. ( PDF; 229 kB).
  6. ↑ Ekkehard Wachmann, Albert Melber, Jürgen Deckert: Bugs Volume 2: Cimicomorpha: Microphysidae (lichen bugs), Miridae (soft bugs) . Goecke & Evers, Keltern 2004, ISBN 3-931374-57-2 .
  7. ↑ a b c Rafaël Govaerts (Ed.): Calamagrostis arenaria. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew , accessed May 25, 2020.
  8. ↑ Georg August Pritzel , Carl Jessen : The German folk names of plants. New contribution to the German language treasure trove. Philipp Cohen, Hannover 1882, p. 71 (online)
  9. ^ Bureau of Land Management Arcata Field Office: South Spit Interim Management Plan 2002 ( PDF ( Memento of September 28, 2007 in the Internet Archive )).

literature

  • Rainer Borcherding: The beach grass. ( PDF ( Memento of September 26, 2007 in the Internet Archive ), accessed on November 24, 2006)
  • HJ Conert: Parey's book of grasses. Recognize and determine the grasses in Germany. Blackwell Wissenschafts-Verlag, Berlin / Vienna 2000, ISBN 3-8263-3327-6 .
  • H. Ellenberg, HE Weber, R. Düll, V. Wirth, W. Werner, D. Paulißen: Pointer values ​​of plants in Central Europe. (= Scripta Geobotanica. 18). Verlag Erich Goltze, 1992, ISBN 3-88452-518-2 .
  • Henning Haeupler , Thomas Muer: picture atlas of the fern and flowering plants of Germany (= the fern and flowering plants of Germany. Volume 2). Published by the Federal Agency for Nature Conservation. Ulmer, Stuttgart 2000, ISBN 3-8001-3364-4 .
  • CE Hubbard: Grasses - Description, Distribution, Uses. Ulmer Verlag, Stuttgart 1985, ISBN 3-8001-2537-4 .
  • E. Oberdorfer: Plant-sociological excursion flora . Ulmer Verlag, Stuttgart 1990, ISBN 3-8001-3454-3 .
  • R. Pott: Color Atlas North Sea Coast and North Sea Islands. Ulmer Verlag, Stuttgart 1995, ISBN 3-8001-3350-4 .
  • K. Rieck: Vegetation-ecological studies of selected dune complexes on the East Frisian Islands Baltrum, Langeoog, Spiekeroog and Wangerooge. Dissertation. University of Hanover, 2000 ( PDF; 5.6 MB).

Web links

Distribution maps

images

Commons : Common beach grass  album with pictures, videos and audio files
This version was added to the list of articles worth reading on July 28, 2008 .