Allee effect

From Biocrawler, the free encyclopedia.

The Allee effect is a phenomenon in biology named after W. C. Allee, who first wrote extensively on it. It describes a positive relation between population density and the per capita growth rate. In other words, for smaller populations, the reproduction and survival of individuals decreases. This effect usually saturates or disappears as populations get larger.

The effect may be due to any number of causes. In some species, reproduction—finding a mate in particular—may be increasingly difficult as the population density decreases. Other species may use strategies (such as schooling in fish) that are more effective for larger populations.

References

• "What is the Allee Effect? (http://evolve.zoo.ox.ac.uk/publications.html?id=185)." Stephens PA, Sutherland WJ & Freckleton RP (1999) Oikos 87, 185-190.. Accessed on February 4, 2005.
• "Underpopulation (Allee) effects (http://classes.entom.wsu.edu/529/Allee.htm)." Alan A. Berryman, Principles of Population Dynamics. Accessed on February 4, 2005.

Further reading

• Animal Aggregations. A study in General Sociology., W. C. Allee, University of Chicago Press

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