Ruderal vegetation
Ruderal vegetation (from Latin rudus `` rubble '') is the name given to the plant world of humanly profoundly influenced locations, the composition of which was not intended by humans, but which are either ignored by them on unused or fallow areas, or on devastated , overused or vegetation-free areas Adjusts floors in a variety of ways.
General
Ruderale locations are profoundly influenced by humans, in that the previous vegetation was destroyed, the soil structure was changed and, as a result, life opportunities were created that differ from the original conditions. On artificial soils, e.g. B. embankments, gravel, rubble heaps , rubble, etc. In the case of spontaneous colonization, ruderal species always appear as the first colonists.
In contrast to the ruderal vegetation , the “weed” vegetation of the cultivated (especially cereal) fields is called segetal vegetation . Although people also call it weeds , the vegetation of the fields is determined by the annual upheaval of plowing and has numerous individual species. Both “weed” vegetation types also share a number of species in common. The vegetation of root crops such as beets or potatoes is more similar to ruderal vegetation than that of grain fields. Above all, the vegetation of the winter grain fields is actually the Segetal vegetation and shows the slightest resemblance to the ruderal vegetation. If a used field falls fallow, the Segetal vegetation disappears after a few years and is replaced by ruderal plant species.
A special case of ruderal vegetation in recent history was the new growth of pioneer plants on the urban rubble and debris created by air raids and ground fighting during World War II. The term rubble flowers , which was used to describe the unfamiliar or previously unknown vegetation in urban areas , was transferred in particular to the narrow-leaved willowherb .
The locations of the ruderal vegetation are as diverse as the human influences on nature itself. B. on railway gravel that is poor in fine soil and nutrients runs completely differently than that next to completely over-fertilized, waterlogged manure or manure sites , although both are classified as rudderal locations. Nutrient-poor ruderal fields arise z. B. also on embankments, cracks in the earth and embankments after construction work, on mining dumps, on unpaved roads or roadsides . Today, however, nutrient-rich ruderal fields are more common. Locations heavily over-fertilized with nitrogen almost always have rudimentary vegetation, as the overconcentration of nutrient salts has a harmful effect on species that are not particularly adapted .
Emergence
From the point of view of evolution, rudder locations are a new phenomenon. There are therefore relatively few plant species that have their origin here and were completely absent from the natural landscape . Most ruderal species have migrated from special locations in the primeval landscape to these locations, or they have migrated from other climatic zones . Many ruderal species originate from the bank zones of large rivers, where the dynamics of flowing water have always created comparable locations. Some species originate from the flushing fringes of the seashore (species that thrive under the influence of salt are particularly well adapted to locations over-fertilized with nitrogen salts ). In the case of some species, there is speculation about earlier occurrences in animal structures or camps, although proof here is virtually impossible. Some species have migrated from the steppe zone or from the Mediterranean area . The proportion of neophytes in ruderal vegetation is particularly high . The proportion of these newly immigrated species is usually less than 5% in near-natural vegetation units, but can rise to 30% and more in ruderal fields. It is assumed that immigrated species have particularly good chances of establishing themselves in ruderal locations with a lot of open soils, little formation from competitive processes and immature plant communities of low evolutionary age.
Ruderal strategy type
In the classic and widely used ordering scheme of the ecologist John Philip Grime, he defines the “ruderal” strategy type as one of the three basic adaptation types of the plant world. Grime defines three types: The "competitive type" (C after English. Competitor) is competitive compared to other plant species, long-lived and thrives best in favorable locations with medium conditions. The “stress tolerance type” (S) is able to thrive under extreme site conditions where other species cannot follow it. The "ruderal type" (R) is short-lived, but widely spreading, it often has a particularly large number of long-lived seeds and forms a persistent seed bank in the soil, from which the species can regenerate even after a long time if the conditions are favorable again . If you plot the species according to their strategy type in a diagram, a triangle forms. Mixed and transition types are found in the middle, types with pure types at the tips.
vegetation
Vegetation stands dominated by ruderal plants can, as usual, be described as plant communities . Due to the heterogeneity and diversity of the ruderal corridors, an extremely large number of units have been described. The superordinate division into classes and orders is quite well clarified and relatively undisputed. On the other hand, there are numerous different, often blatantly contradicting views on the number, delimitation and composition of associations and unrestricted societies.
- Of A - or biennial species controlled, short-lived Ruderalfluren made class Sisymbrietea with the only order Sisymbrietalia. Most of the older authors grouped this order together with the weed vegetation of the root crop fields in the class Chenopodietea.
- The perennial ruderal corridors, mostly made up of tall perennial perennials, belong to the class Artemisietea.
- Nutrient-rich, perfectly trained mostly in partial shade of trees " hem " are companies grouped in class Galio Urticetea. In the past they were mostly placed among the Artemisietea.
- The related " potholes " that grow up when clearing forests are summarized in the class Epilobietea angustifolii.
- The position of the ruderal bushes and forests made up of woody species in the system is highly controversial and difficult to grasp, as these are generally societies with few species.
In the course of the succession , the societies merge into one another. The classic sequence annuals (Sisymbrietea societies) - biennial perennials (Artemisietea societies) - shrub species (Rhamno-Prunetea or ruderal bushes) - trees (pre-forest societies - end forest societies) can be found in many locations, but is by no means generally applicable. It happens relatively often that shrub species and forest tree species such as birch and willow germinate and grow up on bare ground . Long-lived ruderal societies are usually only preserved where the succession is repeatedly interrupted by frequent disturbances . The unaffected succession usually runs much faster on nutrient-rich soils than on nutrient-poor soils. If the seed supply is sufficient, it can reach the pre-forest stage after five years on nitrogen-rich soils.
Plant communities in Central Europe and their soil requirements in examples
Short-lived ruderal corridors
Typical pioneer vegetation on open raw soils is the compass lettuce with the species compass lettuce ( Lactuca serriola ), purslane ( Portulaca oleracea ), Canadian fleabane ( Conyza canadensis ) and Hungarian rocket ( Sisymbrium altissimum ). Especially in large cities, the mouse barley corridor with the eponymous mouse barley ( Hordeum murinum ) forms stocks on roadsides and open fallow land. The Kassel vegetation expert Gerhard Hard dedicated a monograph to this. The mallow fields with common mallow ( Malva neglecta ), small mallow ( Malva pusilla ) and the annual small nettle occupy similar locations, also in villages . Typical for train stations are reporting corridors with glossy messages ( Atriplex nitens ), spit messages ( Atriplex prostrata ) and different seeds ( Atriplex micrantha ). It was not until the mid-1990s that signaling corridors began to spread across the median of the motorways, where the diverse-seeded signaling, with its silvery leaves underneath, formed miles of bands. Widely used e.g. B. along the lanes in the agricultural landscape are also Raukenfluren with Tauber brome ( Bromus sterilis ), and hedge mustard ( Sisymbrium officinale ). This species gave its name to the short-lived ruderal societies as a whole.
Persistent ruderal corridors
Typical of humid, nitrogen-rich locations in warmer locations is the burdock and mugwort field with burdock ( Arctium lappa ) and mugwort ( Artemisia vulgaris ), the eponymous species for the perennial ruderal fields. In somewhat drier locations, they are replaced by tansy and mugwort meadows , in which tansy ( Tanacetum vulgare ) also occurs (in addition to plenty of nettles) . Today, village weed fields with Gutem Heinrich ( Chenopodium bonus-henricus ) and black nettle ( Ballota nigra ) have become quite rare . The hemlock corridor with the highly poisonous spotted hemlock ( Conium maculatum ) prefers similar places . This species has also moved to the motorway median for some time. Carrot and sweet clover corridors populate warmer and drier locations . Societies from this group of relatives are often particularly colorful and blooming, especially in midsummer. Typical species are wild carrot ( Daucus carota ), white sweet clover ( Melilotus albus ), sweet clover ( Melilotus officinalis ), small-flowered mullein ( Verbascum thapsus ) and other Verbascum species, common adder's head ( Echium vulgare ). The conspicuous donkey thistle ( Onopordum acanthium ) is added to even warmer locations . Many of the distinctive species are biennial, which develop a rosette of leaves in the first year, only bloom in the second year and then die off. On sandy soils, species such as roof brusque ( Bromus tectorum ) and evening primrose ( Oenothera biennis agg.) Are added to the same species combination . The goldenrod species Canadian goldenrod ( Solidago canadensis ) and giant goldenrod ( Solidago gigantea ) are frequent companions . In older succession stages they can develop low-species tall herbaceous vegetation almost without any other species.
On nutrient-rich fresh soils, like in partial shade of trees that grows nettle Giersch hallway , next to the eponymous Great nettle ( Urtica dioica ) and the goutweed ( Aegopodium podagraria ), often with Red campion ( Silene dioica ) and Spotted dead nettle ( Lamium maculatum ) . Even more shady locations occupy the inner forest borders , e.g. B. with garlic mustard ( Alliaria petiolata ), clove root ( Geum urbanum ), Gundermann ( Glechoma hederacea ), Ruprecht's herb ( Geranium robertianum ), hedge calf's goiter ( Chaerophyllum temulum ). However, the annual glandular balsam ( Impatiens glandulifera ), which can displace almost all other species due to its height , has been spreading in such locations for several decades, with an increasing tendency .
Ruderale pre-forest societies
Later stages of succession on ruderal sites lead to the penetration of woody species into the ruderal vegetation. The elderberry ( Sambucus nigra ) is often the first species of wood on nitrogen-rich soils . In soils that are poor in nutrients, succession begins with the sand birch ( Betula pendula ), i. H. a shrub stage is missing here. Birch pioneer forests grow over large areas on raw soil with little fine soil, on railway gravel or industrial wasteland. Frequent companions are black locust ( Robinia pseudoacacia ), summer lilac ( Buddleja davidii ), which has been increasing for about two decades, and recently also tree of gods ( Ailanthus altissima ). Instead of the birch forests, thickets of the Armenian blackberry ( Rubus armeniacus ), an overgrown garden plant, can sometimes appear. Thickets and copse of these species can often be found for miles along railway embankments. On better soils, e.g. B. fallow trees, the deciduous tree species sycamore maple ( Acer pseudoplatanus ) and ash ( Fraxinus excelsior ) form characteristic forests, mostly with types of forest inner fringes and elderberry as undergrowth.
See also
literature
- Heinz Ellenberg : Vegetation of Central Europe with the Alps in an ecological, dynamic and historical perspective (= UTB for science. Large series . Volume 8104 ). 5th, heavily changed and improved edition. Eugen Ulmer, Stuttgart (Hohenheim) 1996, ISBN 3-8252-8104-3 .
- Claus-Peter Hutter (Ed.), Annette Otte, Conrad Fink: Farmland and Settlements. Recognize, define and protect biotopes. Weitbrecht , Stuttgart 1999, ISBN 3-522-72061-X .
- Leonie Jedicke, Eckhard Jedicke: color atlas landscapes and biotopes of Germany. Eugen Ulmer, Stuttgart, 1992. ISBN 3-8001-3320-2 .
Individual evidence
- ^ John Philip Grime: Vegetation classification by reference to strategies. In: Nature. Volume 250, 1974: pp. 26-31, doi: 10.1038 / 250026a0
- ^ John Philip Grime: Plant strategies and vegetation processes. Wiley, Chichester, et al. a. 1979, ISBN 0-471-99695-5 , 222 pp.
- ^ Gerhard Hard: Ruderal vegetation: ecology and ethnoecology, aesthetics and "protection". In: Notebook of the Kassler School. Volume 49, 1998, Kassel, ISBN 3-00-003491-9 .
Web links
- Ruderal vegetation - very informative website from Dietmar Brandes, Technical University of Braunschweig
- Plant communities of the Rhineland
- The German plant associations with the Red List at Floraweb