Phenotypic plasticity
The ecological potency or ecological tolerance indicates the area in which one (or more ) environmental factor a species can thrive over time. The ecological potency with respect to various environmental factors is different from species to species.
The Hohenheim groundwater experiment shows an example of the difference between the environmental power and the actual ecological niche. For many species, the synecological optimum is far from optimum autecological away.
Considering the significance of a particular environmental factor for an organism, it is called the ecological valence ( valence, lat = valence ) of this factor. In common parlance, this term is used synonymously with the concept of power, which is not strictly correct since the valence merely referred to the importance of the environmental factor of the existence of the studied organisms.
Distinction
Species that have a wide range of tolerance are as eurypotent ( euryök, eurytolerant; Eurys, Greek = wide) called.
Species that tolerate only a small fluctuation of environmental factors, are as potent shorthand, called ( stenök, tolerant steno steno, Greek: eng). These organisms can be used as indicator species, key forms or indicator organisms, since their occurrence is characteristic of certain biotopes. It is typical for stenöke types that they have a high vitality that drops very quickly outside the optimum.
If we examine the sensitivity to certain environmental factors, can the characterization according to environmental influences further refined.
Representation
Illustrating the range of tolerance or tolerance range, the reaction of the organism in proportion to the environmental factor can be shown schematically in a coordinate system. The tolerance curve (also: to thrive curve) is determined by the characteristic points or regions as well as optimum pessimum. The pessimum is characterized by the two maximum and minimum critical value. These, also called cardinal points of life values , may limit the tolerance range of the type of organism. If the intensity of the environmental factor below the minimum or above the maximum, so the organism is no longer viable under these conditions. Within the Pessimums neither reproduction nor effective prosperity of the living being is possible.
The area around the optimum, the Präferendum or the preference field indicates the preferred by the organism under conditions autecological habitat. The form of life is under these circumstances the greatest vitality and fertility.
Application
Physiological tolerance ranges are determined under the experimental conditions where all other factors are held constant. It is measured the extent to which the factor can vary without the organism is physically detrimental limited.
Based on the occurrence of indicator organisms, the quality of soils or waters seen. Based on the existence of certain plants can be eg salinity or acid value of water bodies recognize.
Examples
Euryök / eurypotent
The Scots pine has in relation to the abiotic factor of water ( in the form of soil moisture ) a very euryöke tolerance width. Since they can grow both on dry and sandy soils as well as on wet peatlands, it has a wide physiological potency.
The dandelion has a large tolerance range with respect to the soil conditions. Omnivores such as rats or pigs are in relation to food very euryöke or euryphage species.
Stenök / steno potent
The trout that can exist only in certain water temperatures, is a stenöke or more precisely stenotherm Art Since the koala can only eat eucalyptus leaves, it is in this a stenökes or steno phages beings.
In the flora, the holm oak is considered stenohygre species.