Realm of existence

The realm of existence is the area of the actual presence of a species, restricted by competition . Within their power range , i. H. its tolerance to location factors , it is influenced by other species by e.g. B. Competition pushed into their area of existence.

In this area of often extreme location factors, the species achieves its ecological optimum because it is superior to other species and therefore can only actually achieve its optimum existence there ( see: ecological potency , tolerance (ecology) ). An area of existence is often characterized by a variety of overlays of all biotic and abiotic location factors. In addition to the abiotic location factors, there are interactions with other species ( interspecific relationships ) in an ecosystem , which trigger competitive pressure and are decisive for the formation of areas of existence.

The concept of the area of existence does not represent a place, i.e. not a habitat or biotope , but an area within several ecological gradients (see also gradient ).

Principle of the areas of existence: sand birch

Formation of the stinging nettle's subsistence level

One can often observe that the range of existence of a species is enlarged in the absence of predators and competitors and vice versa. Competition, e.g. B. by introduced allochthonous species with a similar, overlapping ecological niche , leads to a reduction in the area of existence of the originally existing species. This has led to the concepts of fundamental and realized area of existence.

The fundamental area of existence describes the n-dimensional space defined by the environmental factors in which a species can sustain potentially viable populations.
The realized area of existence is the corresponding sub-space that is occupied when competitors and robbers are present.

If the realized area of existence becomes too small, e.g. B. by the introduction of foreign species, this can lead to the extinction of a species.

The number of possible areas of existence of an ecosystem depends on the climatic or geographical conditions as well as on the rest of the community, the biocenosis . Accordingly, the number of species is very different. Extreme habitats, like the glaciers of Greenland , the Antarctic or the high mountains offer closer existence ranges as virgin forests in the tropics or coral reefs .

See also: