Trophy level

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Schematic representation of a food chain in a European lake (without destructors)

Trophy level , also called trophic level , trophic level or trophic level (from ancient Greek τροφή trophe , German 'nutrition' ), is the designation for a certain level (level) or level of a linear food chain in the ecosystem. With regard to individual species, one sometimes speaks of food chain links .

In the highly simplified and idealized model of a linear food chain, a distinction is made between the autotrophic primary producers , the consumers and the destructors . The consumers often comprise two or more trophic levels, so that first-order consumers ( primary consumers ), second-order consumers ( secondary consumers ), third-order consumers ( e.g. parasites on predators), etc. can be distinguished.

In addition to observable field methods , feeding experiments and classic morphological investigations, isotope-analytical methods allow much more detailed statements about the trophic level of a group of organisms than the above division into a small number of discrete levels suggests.

The trophic cascades represent dynamic aspects in the interaction of the trophic levels .

In fisheries it can be observed that the trophic level of the caught fish has been decreasing for decades.

Individual evidence

  1. ↑ z. B. see S. Pasquaud et al .: Determination of fish trophic levels in an estuarine system . In: Estuarine, Coastal and Shelf Science . tape 86 , no. 2 , January 20, 2010, p. 237–246 , doi : 10.1016 / j.ecss.2009.11.019 ( archives-ouvertes.fr [PDF]).
  2. ^ Daniel Pauly, Villy Christensen, Johanne Dalsgaard, Rainer Froese, Francisco Torres: Fishing Down Marine Food Webs . In: Science . tape 279 , no. 5352 , February 6, 1998, p. 860–863 , doi : 10.1126 / science.279.5352.860 ( ucsc.edu [PDF]).