**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.