Ecological potency
The ecological potency or ecological tolerance is a property of species . It indicates in which range of values a certain environmental factor a species can thrive over a long period of time. This is then referred to as the tolerance range of the species with regard to the environmental factor.
The Hohenheim groundwater experiment shows the difference between the ecological potency and the actual ecological niche . For many species the synecological optimum is far removed from the auto-ecological optimum .
If one considers the value of a certain environmental factor for an organism , one speaks of the ecological valence (valence, Latin = value) of this factor. In common parlance , this term is used synonymously with the term potency , which, strictly speaking, is not correct, since the valence merely describes the significance of the environmental factor concerned for the existence of the living beings examined.
Distinction
Species that have a large tolerance range are called eurypotent ( euryök , eurytolerant; eurys, Greek = broad).
Species that tolerate only a slight fluctuation in environmental factors are called stenopotent ( stenök , stenotolerant; steno, Greek = eng). These organisms can be used as pointer types , lead forms or indicator organisms , as their occurrence is characteristic of certain biotopes . It is typical of stern species that they have a high level of vitality, which falls very quickly outside of the optimum.
If one examines the sensitivity to certain environmental factors, the characterization can be further refined according to the environmental influences.
| Environmental factor | suffix |
|---|---|
| food | eury phag / steno phag |
| Salinity | eury halin / steno halin |
| temperature | eury therm / steno therm |
| Soil moisture | eury hygr / steno hygr |
| Oxygen content | eury oxygen / steno oxygen |
| Water depth | eury batic / steno batic |
| geographical location | eury top / steno top |
presentation
To illustrate the tolerance range or the tolerance range , the reaction of an organism in relation to the environmental factor can be shown schematically in a coordinate system . The tolerance curve (also: growth curve ) is determined by the characteristic points or areas optimum and pessimum . The pessimum is characterized by the two critical values maximum and minimum . These values , also known as the cardinal points of life, limit the tolerance range of the organism species. If the intensity of the environmental factor is below the minimum or above the maximum, the organism is no longer viable under these conditions. Within the pessimum, neither reproduction nor effective growth of the living being is possible.
The area around the optimum, the preference or the preference area , indicates the habitat preferred by the organism under autecological conditions . The life form shows the greatest possible vitality and reproduction under these circumstances .
application
Physiological tolerance ranges are determined under experimental conditions in which all other factors are kept constant. It is measured to what extent the factor can fluctuate without the organism being impaired physically.
Based on the occurrence of indicator organisms, the quality of soil or water can be recognized. Based on the existence of certain plants, z. B. recognize the salinity or acidity of water.
Examples
Euryök / eurypotent
The Scots pine has a very Eurocean tolerance range in relation to the abiotic factor water (in the form of soil moisture). Since it can grow on dry and sandy soils as well as on moist bog locations , it has a broad physiological potency.
The dandelion has a large tolerance range in terms of soil conditions. Omnivores such as rats or pigs are very euryphagous species in terms of food .
Stenok / stenopotent
The trout , which can only exist at certain water temperatures, is a stenoic or more precisely stenothermic species. As the koala can only feed on eucalyptus leaves, it is a stenoic or stenophageous creature.
In the flora, the holm oak is considered a stenohygre species.
See also
Individual evidence
- ↑ Lexicon of Biology, Spectrum. Heidelberg 2002, Vol. 10, p. 220.
- ↑ so also in: Linder: Biologie, Schroedel ISBN 978-3-507-10101-2 , 2010, p. 517; also: dtv-Atlas zur Ökologie, dtv 3228, p. 57; also: Hans Knodel / Ulrich Kull: Ecology and environmental protection, j. B. Metzler; ISBN 3 476 20068X , p. 21.
- ↑ Guderian (Hrsg.) 2001: Handbook of environmental changes and ecotoxicology: Volume 2A: Terrestrial ecosystems. Immission ecological basics - Effects on soil - Effects on plants. Page 2 Springer Verlag. Berlin. Retrieved online from books.google.com .
- ↑ wasser-wissen.de , accessed on April 29, 2009.