As poor grassland different types of extensively used are grassland at particularly low in nutrients , "lean" locations summarized. The species composition of this type of biotope is characterized by herbaceous and subshrub plants . A dry grassland is a type of poor grassland in which drought is the main cause of low yield. Today most of the grasslands are threatened. As a retreat for a large number of endangered species, the remaining areas are often specially protected .
Generally as poor grassland , with mowing as poor meadows , with grazing as poor pastures , mostly transitional stands between “real” poor grassland and intensive grassland are referred to. They can be just as rich in species and flowers as the actual grasslands, although their species population is mixed. They have often emerged from poor grassland through poor fertilization . According to plant-sociological nomenclature, one would not speak particularly elegantly of "lean fat meadows".
If you were to look at an ideal, grazed slope in a karst region like the Swabian Alb in the 19th century, you would find dry grass in the driest and most sun-exposed places , semi-dry grass with increasing moisture , then poor pastures and finally fat pastures at the bottom of the valley . Dry grass and semi-dry grass are scientific subdivisions of lean grass that were not made agriculturally.
In contrast to the poor and rich pastures, the poor grasslands were only grazed extensively with sheep and goats. In the potential forest vegetation of Central Europe, permanent grazing by at least 30 to 50 livestock units on 100 hectares leads to the sustainable creation of a forest-free pasture: this corresponds to 30 to 50 adult cattle or around 300 to 500 sheep.
Since most of the traveling sheep farms were abandoned at the end of the 19th century, the grasslands have changed dramatically. Either the pasture management was intensified through artificial fertilization or the pastures were reforested or simply left to be covered with bushes.
To distinguish it from fat grassland, the term lean refers to the lower yield. Secondly, due to the important relationship, one also thinks of the nutrient content, but this is not the only factor that determines the yield. This meaning is not to be confused with the use in soil science, where clay-rich loam is called fat , and loam poor in clay is called lean .
Lean lawns occur on different soils and types of soil, all of which have in common their lack of nutrients, especially nitrogen. Most of the stocks are found on extreme soils with special site conditions, since soils in "medium" locations have mostly been changed by agriculture through fertilization. Lean grasslands on calcareous soils (dry calcareous grasslands) are particularly rich in flowers . On acidic soils, they mainly occur on sand (dry sand grassland) , often interlocking with heather . Alpine meadows and alpine mats also usually represent poor grasslands. Plant species in the grasslands often have a high level of drought resistance . What is crucial, however, is their ability to thrive on nutrient-poor soils. The types of grasslands are subject to other plants in the fight for survival in fertilized meadows and pastures due to their low competitive power .
Lean lawns as a plant community of nutrient-poor locations go back to human activity in Central Europe. They were mostly created by grazing originally forested areas. Since the grazing animals (especially goats and sheep) bite the young trees and bushes , the grazed Hutewald opens up more and more, clearings emerge, until finally the woody plants disappear completely and a poor lawn remains. Lean lawns were therefore typical for the parts of the district shared by all the villagers, the common land (also known as “Mark”, “Hute”, “Heide” etc. in the region). Under today's agricultural conditions, the cultivation of grasslands is no longer profitable. They are often referred to in the cadastre as " wasteland " or " wasteland ". The previously existing rough lawns have therefore been either ameliorated by fertilization or afforested, with the exception of small remains .
It is controversial whether natural grasslands could also have existed to a lesser extent in Central Europe. According to the “mega-herbivore hypothesis”, they are possibly partly relics of natural pasture lawns, as they could have been created by the grazing activity of naturally occurring large herbivores before humans appeared in the landscape of that time. Only the extermination of the large grazing animals by humans led to the pushing back of the open grasslands of Central Europe. Goods for the prehistoric extinction of large herbivores mammoths , Altelephant , rhinoceros , woolly rhino and steppe bison climate alongside the hunt may partly responsible, as is the extinction or the widespread eradication of wild horse , giant deer , elk , bison , bison , cave bear and brown bear , the once populated our landscape in large numbers, conditioned by man. The vegetation expert E. Gradmann called these (hypothetical) natural grasslands in southern Germany “steppe heaths”. The originally park-like pasture forests were passed on in the vicinity of human settlements from the Neolithic period onwards through the usual forest pasture of domestic animals and have spread in the course of the further development of pasture management. Most of the animal and plant species of the grasslands in Central Europe do not have their distribution center due to the human-sponsored development. Many species come from the (natural) steppes of Eastern Europe or have migrated from the rocky grasslands of the Mediterranean region ( Garigue ).
Lean lawns are ecosystems created (or at least strongly promoted) through extensive agricultural use (single hay meadows or sheep pastures ) on nutrient-poor areas, in which only extensive land use took place in pre-industrial agriculture . The migratory sheep farm, for which large areas of pasture were needed, was typical of poor grassland. Accordingly, even today they can only be maintained permanently through use (or as a replacement through adapted care). If their use is permanently discontinued, they will be wasted and many of the special animal and plant species will be lost.
Areas on military training areas can be cited as an exotic example of today's use with the formation of poor grassland . The constant tearing up of the vegetation cover of sandy, shallow locations, as a result of the driving activity of tracked vehicles, also pushes back woody plants. Since military training areas (in contrast to almost all areas used for agriculture today) are not fertilized, poor grasslands can arise (example: Mainz sand ).
Types of grasslands
- Lean sand grassland, see dry sand grassland
- Lime grassland
- Dry steppe grasslands, in eastern Central Europe
- Heavy metal grasslands, e.g. B. in the Harz and Harz foreland, see heavy metal lawn
- Bristle grass lawn
In addition to these types, which are primarily related to vegetation, landscape names are also common. The lean lawns summarized in this way correspond to one of the types listed above in terms of vegetation.
Nature conservation / maintenance measures
The conditions mentioned make the grasslands a refuge for endangered animal and plant species. Many Red List species exist here. In order to maintain the poor grassland and prevent it from developing into wood ( bushes ), the areas usually have to be cared for. The maintenance measures include extensive grazing (grazing by sheep ) and de-bushing measures ( de-puddling ). These animals nibble off the offspring of bushes and shrubs, thereby preventing the growth of trees. Juniper bushes are, however, often found on grasslands because grazing animals avoid them.
- Dry grassland , ruderal vegetation
- Griesheimer Sand
- Hainburg Mountains
- Meager meadow near Potshausen
- Camp Reinsehlen
- Olaf von 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.
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- B. Beinlich, H. Plachter (Ed.): Protection and development of the limestone grasslands of the Swabian Alb. In: Supplement publications for nature conservation and landscape management in Baden-Württemberg. Volume 83, 1995.
- Katja Funke (edit.): Heavy metal lean grasslands and heaths in the Harz as well as heavy metal lean grasslands along Innerste and Oker in the Harz foreland. Recording of the biotopes protected according to § 28a NNatG. Seesen 1995.
- Heiko Rein: Natural treasures of the Rhön. Limestone grasslands. Kaltensundheim 1997, .
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- wikt: lean