Editing Habitat fragmentation (section)

==== Genetic drift ====
Small populations are more susceptible to [[genetic drift]]. Genetic drift is random changes to the genetic makeup of populations and leads to reductions in genetic diversity. The smaller the population is, the more likely genetic drift will be a driving force of evolution rather than natural selection. Because genetic drift is a random process, it does not allow species to become more adapted to their environment. Habitat fragmentation is associated with increases to genetic drift in small populations which can have negative consequences for the genetic diversity of the populations.<ref name="Pavolva2017" /> However, research suggests that some tree species may be resilient to the negative consequences of genetic drift until population size is as small as ten individuals or less.<ref name="Borrell2018" />

===== Genetic consequences of habitat fragmentation for plant populations =====

Habitat fragmentation decreases the size and increases plant populations' spatial isolation. With [[genetic variation]] and increased methods of inter-population [[genetic divergence]] due to increased effects of [[Genetic drift|random genetic drift]], elevating [[inbreeding]] and reducing gene flow within plant species. While genetic variation may decrease with remnant population size, not all fragmentation events lead to genetic losses and different types of genetic variation. Rarely, fragmentation can also increase gene flow among remnant populations, breaking down local genetic structure.<ref>{{Cite journal|last1=Young|first1=Andrew|last2=Boyle|first2=Tim|last3=Brown|first3=Tony|date=1996|title=The population genetic consequences of habitat fragmentation for plants|journal=Trends in Ecology & Evolution|language=en|volume=11|issue=10|pages=413–418|doi=10.1016/0169-5347(96)10045-8|pmid=21237900|bibcode=1996TEcoE..11..413Y }}</ref>