Stratification (vegetation)

Stratificationin the field ofecologyrefers to the vertical layering of ahabitat;the arrangement ofvegetationin layers.^[1]^[2]It classifies the layers (sing.stratum,pl.strata) of vegetation largely according to the different heights to which theirplantsgrow. The individual layers are inhabited by different animal^[3]and plantcommunities(stratozones).

Vertical structure in terrestrial plant habitats

Forest with canopy, shrub and herb layers of vegetation

The following layers are generally distinguished:forest floor(rootandmosslayers),herb,shrub,understoryandcanopylayers. These vegetation layers are primarily determined by the height of their individual plants, the different elements may however have a range of heights. The actual layer is characterised by the height range in which the vast majority ofphotosyntheticorgans (predominantlyleaves) are found. Taller species will have part of their shoot system in the underlying layers. In addition to the above-ground stratification there is also a “root layer”. In the broadest sense, the layering ofdiasporesin the soil may be counted as part of the vertical structure. The plants of a layer, especially with regard to their way of life and correspondingly similar root distribution interact closely and compete strongly for space, light, water and nutrients. The stratification of aplant communityis the result of longselectionandadaptationprocesses. Through the formation of different layers a given habitat is better utilized. Strongly vertically stratified habitats are very stableecosystems.The opposite is not true, because several less stratified vegetation types, such asreed beds,can be very stable. The layers of a habitat are closely interrelated and at least partly interdependent. This is often the case as a result of the changes in microclimate of the top layers, the light factor being of particular importance.^{[citation needed]}

View of the canopy and understory beneath

Besides the superposition of different plants growing on the same soil, there is a lateral impact of the higher layers on adjacent plant communities, for example, at the edges of forests and bushes. This particular vegetation structure results in the growth of certain vegetation types such as forest mantle and margin communities.^{[citation needed]}

Tree layer

This layer of vegetation starts from a height of about 5 metres and comprises the top stratum, which consists ofphanerophytes.They can be about 45 metres high. The trees (and sometimes shrubs) are of various heights. One tree has itscrownat the height of another’s trunk. At the top the crowns of the different species of trees form a more or less closed canopy. This layer creates special ecological conditions in the underlying layers offorests.The density of the trees determines the amount of light inside the forest. The force of heavy rainfall is reduced by the canopy and the passage of rainwater is fed more slowly downwards. The tree layer can be further subdivided into the upper tree layer or canopy and the lower tree layer or understory.^{[citation needed]}

Canopy

The canopy usually refers to the highest layer of vegetation in a forest or woodland, made up of the crowns of its tallest trees. However, individual trees growing above the general layer of the canopy may form anemergent layer.^{[citation needed]}

Understory

The understory can refer to those trees above the shrub layer and below the canopy, but is often defined more broadly, including the shrub layer.^{[citation needed]}

Shrub layer

The shrub layer is the stratum of vegetation within a habitat with heights of about 1.5 to 5 metres. This layer consists mostly of young trees and bushes, and it may be divided into the first and second shrub layers (low and high bushes). The shrub layer needs sun and little moisture, unlike the moss layer which requires a lot of water. The shrub layer only receives light filtered by the canopy, i.e. it is preferred by semi-shade or shade-loving plants that would not tolerate bright sunlight. Small to medium sized birds sometimes known asbush nestersare often found in the shrub layer where their nests are protected by foliage. European examples include blackbird, song thrush, robin or blackcap. In addition to shrubs, such as elder, hazel, hawthorn, raspberry and blackberry, clematis may also occur while, in other parts of the world, vines andlianasmay form part of this stratum. At the edge of awoodlandthe shrub layer acts as a windbreak close to the trees and protects the soil from drying out.^{[citation needed]}

Herb layer

This layer contains mostly non-woody vegetation, orground cover,growing in the forest with heights of up to about one and a half metres. The herb layer consists of variousherbaceous plants(therophytes,geophytes,cryptophytes,hemicryptophytes), dwarf shrubs (chamaephytes) as well as young shrubs or treeseedlings.In forests, earlyflowering plantsappear first before the canopy fills out. Thereafter, the amount of light available to plants is significantly reduced and only those that are suited to such conditions can thrive there. By contrast,grasslandconsists of onlymossand herb layers. Sometimes, a shrub layer builds up in grasslands as part of a process of spontaneousreforestation(ecological succession).^{[citation needed]}

Forest floor

The termforest floorcan refer to the moss and root layers (see below), but often is defined more broadly, including also dead trees, herbaceous plants, mushrooms, and tree seedlings.^{[citation needed]}

Moss layer

Growing on the surface of the forest floor is vegetation of up to about 0.15 metres in height in what is variously described as a moss, soil orcryptogamlayer. The ground itself is covered by a layer of dead plant and animal material. In this layer and the underlying few centimetres of thetopsoillive innumerable small soil organisms such asbacteria,fungi,algaeandmicroorganisms,which break down the dead organic substances and work them into the soil. In places the ground is covered bylichensandmosses.^{[citation needed]}

Root layer

Also known as therhizosphere,the underground area of a plant habitat is the root layer. It consists of the plants' roots and related elements such asrhizomes,bulbsandtubers.^{[citation needed]}

References

^Whittow, Dictionary of Physical Geography.
^"Nine Layers of the Edible Forest Garden (Food Forest) | Temperate Climate Permaculture".27 May 2013.
^Gomes, Dylan G. E.; Appel, Giulliana; Barber, Jesse R. (18 December 2020)."Time of night and moonlight structure vertical space use by insectivorous bats in a Neotropical rainforest: an acoustic monitoring study".PeerJ.8:e10591.doi:10.7717/peerj.10591.ISSN 2167-8359.PMC7751414.PMID 33384906.

Bibliography

Dierschke, Hartmut (1994).Pflanzensoziologie Grundlagen und Methoden; 55 Tabellen(in German). Stuttgart.ISBN 3-8252-8078-0.OCLC 231620702.{{cite book}}:CS1 maint: location missing publisher (link)
C. S. Elton:Animal Ecology.Sidgwick & Jackson, London, 1927.
M. Schaefer:Wörterbuch of the Ökologie.Spektrum, Jena, 1992.ISBN 3-8252-0430-8

[1] Whittow, Dictionary of Physical Geography.

[2] "Nine Layers of the Edible Forest Garden (Food Forest) | Temperate Climate Permaculture".27 May 2013.

[3] Gomes, Dylan G. E.; Appel, Giulliana; Barber, Jesse R. (18 December 2020)."Time of night and moonlight structure vertical space use by insectivorous bats in a Neotropical rainforest: an acoustic monitoring study".PeerJ.8:e10591.doi:10.7717/peerj.10591.ISSN 2167-8359.PMC7751414.PMID 33384906.

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