Editing Allee effect (section)

===Demographic stochasticity===
Demographic stochasticity refers to variability in population growth arising from sampling random births and deaths in a population of finite size.<ref>{{Cite book|chapter-url=http://oxfordindex.oup.com/view/10.1093/acprof:oso/9780198525257.003.0001|chapter=Demographic and environmental stochasticity|last1=Lande|first1=Russell|last2=Engen|first2=Steinar|last3=SÆther|first3=Bernt-Erik|pages=1–24|language=en|doi=10.1093/acprof:oso/9780198525257.003.0001|title=Stochastic Population Dynamics in Ecology and Conservation|year=2003|isbn=9780198525257|access-date=2017-10-11|archive-date=2018-11-27|archive-url=https://web.archive.org/web/20181127064611/http://oxfordindex.oup.com/view/10.1093/acprof:oso/9780198525257.003.0001|url-status=dead}}</ref> In small populations, demographic stochasticity will decrease the population growth rate, causing an effect similar to the Allee effect,<ref>{{cite journal | vauthors = Lande R | year = 1998 | title = Demographic stochasticity and Allee effect on a scale with isotropic noise | journal = Oikos | volume = 83 | issue = 2| pages = 353–358 | doi=10.2307/3546849| jstor = 3546849 | bibcode = 1998Oikos..83..353L }}</ref><ref>{{Cite Q| Q56486427}}</ref> which will increase the risk of population extinction. Whether or not demographic stochasticity can be considered a part of Allee effect is somewhat contentious however. The most current definition of Allee effect considers the correlation between population density and mean individual fitness. Therefore, random variation resulting from birth and death events would not be considered part of Allee effect as the increased risk of extinction is not a consequence of the changing fates of individuals within the population.<ref>{{Cite journal |vauthors=Bessa-Gomes C, Legendre S, Clobert J |year=2004 |title=Allee effects, mating systems and the extinction risk in populations with two sexes |journal=Ecology Letters |volume=7 |pages=802–812 |doi=10.1111/j.1461-0248.2004.00632.x |issue=9|bibcode=2004EcolL...7..802B }}</ref>
 
Meanwhile, when demographic stochasticity results in fluctuations of sex ratios, it arguably reduces the mean individual fitness as population declines. For example, a fluctuation in small population that causes a scarcity in one sex would in turn limit the access of mates for the opposite sex, decreasing the fitness of the individuals within the population. This type of Allee effect will likely be more prevalent in [[monogamy|monogamous]] species than [[polygyny|polygynous]] species.<ref>{{cite journal |vauthors=Engen S, Lande R, Saether BE |year=2003 |title=Demographic stochasticity and Allee effects in populations with two sexes |journal=Ecology |volume=84 |pages=2378–2386 |doi=10.1890/02-0123 |issue=9|bibcode=2003Ecol...84.2378E }}</ref>