Editing Allee effect (section)

==Effects on range-expanding populations==

Demographic and mathematical studies demonstrate that the existence of an Allee effect can reduce the speed of range expansion of a population<ref>{{Cite journal |vauthors=Lewis MA, Kareiva P |year=1993 |title=Allee dynamics and the spread of invading organisms |journal=Theoretical Population Biology |volume=43 |pages=141–158 |doi=10.1006/tpbi.1993.1007 |issue=2|bibcode=1993TPBio..43..141L }}</ref><ref>{{Cite journal |author =Lewis MA, [[Pauline van den Driessche|van den Driessche P]] |year=1993 |title=Waves of extinction from sterile insect release |journal=Mathematical Biosciences |volume=116 |pages=221–247 |doi=10.1016/0025-5564(93)90067-K |pmid=8369600 |issue=2}}</ref><ref>{{Cite journal |vauthors=Tobin PC, Whitmire SL, Johnson DN, Bjørnstad ON, Liebhold AM |year=2007 |title=Invasion speed is affected by geographic variation in the strength of Allee effects |journal=Ecology Letters |volume=10 |pages=36–43 |doi=10.1111/j.1461-0248.2006.00991.x |pmid=17204115 |issue=1|bibcode=2007EcolL..10...36T |s2cid=6027336 }}</ref><ref>{{Cite journal |vauthors=Johnson DM, Liebhold AM, Tobin PC, Bjørnstad ON |year=2006 |title=Allee effects and pulsed invasion by the gypsy moth |journal=Nature |volume=444 |issue=7117 |pages=361–363 |doi=10.1038/nature05242|pmid=17108964 |bibcode=2006Natur.444..361J |s2cid=4432173 }}</ref> and can even prevent biological invasions.<ref name=Gar12>{{Cite journal |vauthors=Garnier J, Roques L, Hamel F |year=2012 |title=Success rate of a biological invasion in terms of the spatial distribution of the founding population |journal=Bulletin of Mathematical Biology |volume=74 |pages=453–473 |doi=10.1007/s11538-011-9694-9 |pmid=21972031 |issue=2|s2cid=23554577 |url=https://hal.archives-ouvertes.fr/hal-01257398/file/grh.pdf }}</ref>

Recent results based on spatio-temporal models show that the Allee effect can also promote genetic diversity in expanding populations.<ref name=Roq12>{{Cite journal |vauthors=Roques L, Garnier J, Hamel F, Klein EK |year=2012 |title=Allee effect promotes diversity in traveling waves of colonization |journal=Proceedings of the National Academy of Sciences of the USA |doi=10.1073/pnas.1201695109 |volume=109 |issue=23 |pages=8828–33 |pmid=22611189 |pmc=3384151|bibcode = 2012PNAS..109.8828R |doi-access=free }}</ref> These results counteract commonly held notions that the Allee effect possesses net adverse consequences. Reducing the growth rate of the individuals ahead of the colonization front simultaneously reduces the speed of colonization and enables a diversity of genes coming from the core of the population to remain on the front. The Allee effect also affects the spatial distribution of diversity. Whereas spatio-temporal models which do not include an Allee effect lead to a vertical pattern of genetic diversity (i.e., a strongly structured spatial distribution of genetic fractions), those including an Allee effect lead to a "horizontal pattern" of genetic diversity (i.e., an absence of genetic differentiation in space).<ref name=Roq12 />