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Density dependence

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Definition

noun

(population ecology) An effect in which the intensity changes with the increasing population density, e.g. the effects in which the intensity increases with the increasing population density


density-dependent adj.

(population ecology) Of, pertaining to, characteristic of density dependence


Supplement

In population ecology, density dependence pertains to the effect of the present and/or the past population sizes on the per capita population growth rate.1 Density-dependent processes take place when population growth rates are regulated by population density.2

Density dependence may either be positive or negative. A positive density dependence is one in which the population growth is regulated by an increased population density. An example of a positive density dependence is observed in the population density of Schistosomes. The higher the population density of Schistosomes the higher is the probability of mating pairs and reproduction.3 In contrast, a negative density dependence pertains to a situation wherein the population growth is restricted due to crowding, predators, and competition.


See also:


Reference(s):
1 Sale, P. (2002). Coral reef fishes : dynamics and diversity in a complex ecosystem. Amsterdam: Academic Press. p304.
2 Hixon, M (2009), Density Dependence and Independence, Chichester: John Wiley & Sons Ltd,
3 May, R.M. (1977). "Togetherness among Schistosomes: its effects on the dynamics of the infection". Elsevier North-Holland, Inc.: 301–343.