Dry grass

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Semi- arid grassland ( Mesobromion erecti ) on a south-facing shell limestone slope in the Rhön , with rich populations of the common pasque flower

Arid grasslands are special biotopes that develop in dry , nutrient-poor locations . Low herbaceous and subshrub plants grow in the dry grassland . Types of steppe vegetation are typical , but high mountain species and orchids are also common.

Site conditions

Particularly warm, dry limestone lawns are the preferred location for the small spider ragwort

Dry grasslands develop on dry locations with an only slightly developed, shallow soil profile . Soil types on which dry grass communities develop are Syroseme (on loose rock such as sand), Rendzinen (on limestone), Ranker (on silicate rock).

The locations are often on south-facing slopes with good drainage conditions . But gritty -sandige lowland soils with good Sickervermögen promote the development of dry grasslands. The mostly already sparse amount of precipitation is quickly removed or evaporated . In addition to the moisture conditions , such locations on a steep slope can be subject to increased mass movement ( solifluction ).

As a result of these conditions, the existing soil profiles have only a low level of development and low nutrient replenishment capacity.

Emergence

Because of the lack of water and nutrients , plant species that are highly drought- resistant settle on dry grassland . Although these species could also exist in better-supplied locations, they are subject to other plants there because of their low competitive power .

The dry grassland as a natural plant community in nutrient-poor locations only exists in rare cases, for example on steep slopes. Many representatives of this type were favored in their development by extensive agricultural use (single hay meadows or sheep pastures) on dry, nutrient-poor areas.

Sandy, shallow areas on former military training areas can be named as unusual examples . The constant tearing of the vegetation cover by tracked vehicles led to similar development conditions (example: Mainzer Sand ).

Breakdown

The dry grass vegetation form can be broken down according to site conditions and characteristics. The rock (sand, limestone, silicate rock) plays an important role.

Dry sand lawn

Dry sand lawn with blue shrub grass, mosses and
cracks in the ground in the sandy area near Darmstadt

Sand dry lawns are weak -growing plant communities dominated by grasses and low-growing plants on relatively humus and nutrient-poor sandy soils. The defining features of this biotope are the low storage capacity of water, the low nutrient content of the soil substrate and relatively extreme temperature differences. During the day there can be a rapid high temperature rise under sunlight and at night an equally rapid cooling.

The meager, but species-rich, dry sand grass or sand-poor grassland is mainly found in landscapes with free, sandy ridges and moraine tongues shaped by the Ice Age. The loose, often patchy vegetation made up of grasses and low-growing herbs is gray-green to brownish in color.

Flora: Typical plant species are u. a. the sand carnation , the heather carnation , the mountain sand bell , sedum species and the field hornwort . Sandy grasslands can also be very rich in lichen .

Fauna: Numerous animal species - especially insects - are adapted to the dry sandy grassland habitat. These include many species that also need vegetation-free areas in the poor grass, as the sand here warms up particularly strongly when exposed to sunlight. Typical types of sand lean turf are different wasp species, such as the centrifugal wasp ( bembiX rostrata ). Also Wildbienen about from the group of colletes (genus Colletes), trousers bees (genus Dasypoda) and sand bees (genus Andrena) like nest in sand lean lawn. The blue-winged wasteland insect is a very rare species of locust in this habitat. The striking blue colored hind wings are only visible when they fly up. But there are also many ground beetles , such as the petite colored grave runner ( Poecilus lepidus ) to be found here.

Formation: In the past, dry sand lawns inhabited natural dune locations, dynamic floodplains and their sandy areas, in which new sand areas repeatedly emerged as a result of river bed shifts and floods. Due to the massive expansion of the lower reaches of rivers since the end of the 19th century, the deepening of fairways, bank reinforcements and the construction of barrages, the remaining dry grassland locations there have almost disappeared due to bush encroachment as a normal succession . Various sand locations were also used as building ground or the sand there was mined as a raw material.

Today, sandy grasslands are mostly found in anthropogenic habitats in Central Europe, for example on extensively grazed inland dunes , on the edge of floodplains , or in hud areas on sandy locations with poor bases. In this historical cultural landscape , the types of sandy grasslands found a new habitat and were widely distributed.

However, these habitats have also disappeared more and more from the landscape in the last few decades, because they were either meliorated and fertilized or no longer grazed at all in an increasingly intensively used landscape due to their low economic benefit . In some regions, dry sand grasslands could find retreat areas in the post-mining landscape and on military training grounds.

A typical sand-dry grass flora has developed in the nature reserve Windmühlenberg in Berlin-Gatow . With up to ten meters thick sand deposits on the slope of the Nauener Platte to the Havelniederung , the soil offers the conditions for the development of this type of lawn.

Dry lime grass

The locations of the limestone grasslands are often on south-facing slopes with good drainage conditions . The mostly sparse amount of precipitation is quickly removed or evaporated . As a result of these conditions, the existing soil profiles have only a low level of development and low nutrient replenishment capacity. Shallow limestone soils form the ideal subsurface . The characteristics of the lean lawn are sparse short grasses and a wide variety of slow-growing flowers, like Pasque , silver thistle and small gentians .

A juniper heather (gentian-schillergrass lawn) in the Werra Valley , Thuringia

They are typical of southern Central Europe, which is characterized by a continental climate. Their counterparts in north-western Central Europe, which is characterized by an oceanic climate, are the heaths , and in the high alpine terrain, the mats .

The dry limestone lawn is one of Central Europe's most species-rich plant communities. This form of dry grass is bound to lime-rich or base-rich soils.

Other forms

  • Dry steppe grassland (clay)
  • Transitional forms with more favorable nutrient and moisture conditions such as grasslands and semi-arid grasslands (see also Lechtalheiden )
  • Silicate dry grass
  • Juniper heather (this term is common, but says nothing about the plant community)
  • Brenne , dry grassland biotope in alluvial forests

The natural succession (further development) of dry grass leads it under Central European climatic conditions to drought-resistant forest communities such. B. the orchid beech forest .

Nature conservation / maintenance measures

The conditions mentioned make the dry grassland a refuge for endangered animal and plant species. Many Red List species exist here. In order to protect the dry lawn and prevent it from developing into wood, the areas must be cared for regularly. The maintenance measures include extensive grazing (grazing by sheep and goats) and de-bushing measures ( de-puddling ).

literature

  • OV Drachenfels: Red list of endangered biotope types in Lower Saxony . In: Nature conservation and landscape management in Lower Saxony . Volume 34, 1996, pp. 1-146.
  • G. Jeckel: Syntaxonomic structure, distribution and living conditions of north-west German dry sand lawns (Sedo-Scleranthetea) . In: Phytocoenologia . Volume 12, Issue 1, 1984, pp. 9-153.
  • A. Jentsch, W. Beyschlag, W. Nezadal , T. Steinlein and W. Welß: Soil disturbance - driving force for vegetation dynamics in sand habitats . In: Nature conservation and landscape planning . Volume 34, Issue 2/3, 2002, pp. 37-44.
  • Heinz-Dieter Krausch : The dry sand grass (Sedo-Scleranthetea) in Brandenburg . In: Communications of the Floristic-Sociological Working Group . New series Volume 13, 1968, pp. 71-100.
  • R. Pott and J. Hüppe: The Hudelandschaften northwestern Germany . In: Treatises from the Westphalian Museum for Natural History . Volume 53, Issue 1/2, Münster 1991
  • R. Tüxen: On the history of the dry sand grassland (Festuco-Sedetalia) in the north-west German old Diluvium . In: Communications of the Floristic-Sociological Working Group . New series Volume 8, 1960, pp. 338–341.
  • B. Beinlich and H. Plachter (eds.): Protection and development of the limestone grasslands of the Swabian Alb . Supplement Publications for Nature Conservation and Landscape Management Baden-Württemberg, Volume 83, 1995
  • Irene Drozdowski, Alexander Mrkvicka: Trockenrasen im WienerWald , { https://www.bpww.at/sites/default/files/download_files/TroRa%20Buch_20170111_Homepage_SMALL.pdf Online