Functional response

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In ecology, functional response is a term used to describe the relationship between the density of prey in a certain area and the average number of prey consumed by each predator in that area. The concept was introduced by work on small mammals by C.S. Holling, a Canadian ecologist, that studied how predator per capita consumption of prey changed with prey density.^[1]

Much like survivorship curves, there are three generalized types of functional response curve. In a type 1 curve, feeding rate increases linearly with prey availability then abruptly levels off. In a type 2 curve it levels off more gradually as relative time spent handling prey increases. In a type 3 curve, rare prey are overlooked such that an S-shaped curve results. This is similar to a type 2 curve, but the increasing predation rate at lower numbers is the result of predators forming a search image of prey and thus increasing their rate of hunting.

Functional response is distinct from numerical response, which measures how the number of predators in an area vary with the density of prey.

The equivalent of functional response in phototrophs is photosynthetic response.

[edit] See also

• Ecosystem model
• Predator satiation

[edit] References