Density dependence

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:

• population density
• Density dependent factor

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.