Editing Habitat fragmentation (section)

== Causes ==

===Natural causes===
Evidence of [[habitat destruction]] through natural processes such as [[volcanism]], fire, and [[climate variability and change|climate change]] is found in the fossil record.<ref name="SahneyBentonFerry2010LinksDiversityVertebrates" />{{Failed verification|date=February 2018}}Studies have demonstrated the impacts of individual species at the landscape level<ref name="auto">{{Cite journal |last1=McLachlan |first1=S.M |last2=Bazely |first2=D.R |date=October 2003 |title=Outcomes of longterm deciduous forest restoration in southwestern Ontario, Canada |url=http://dx.doi.org/10.1016/s0006-3207(02)00248-3 |journal=Biological Conservation |volume=113 |issue=2 |pages=159–169 |doi=10.1016/s0006-3207(02)00248-3 |bibcode=2003BCons.113..159M |issn=0006-3207|url-access=subscription }}</ref> For example, From research the results show that the impact of deer herbivory on forest plant communities can be observed at the landscape level at the Rondeau Provincial park for the period of 1955-1978<ref name="auto"/> and also,  [[Carboniferous rainforest collapse|habitat fragmentation of tropical rainforests in Euramerica]] 300 million years ago led to a great loss of amphibian diversity, but simultaneously the drier climate spurred on a burst of diversity among reptiles.<ref name="SahneyBentonFerry2010LinksDiversityVertebrates" />

===Human causes===
Habitat fragmentation is frequently caused by humans when [[native plant]]s are cleared for human activities such as [[agriculture]], [[Subdivision (land)|rural development]], [[urbanization]] and the creation of [[hydroelectric]] reservoirs. Habitats which were once continuous become divided into separate fragments. Due to human activities, many tropical and temperate habitats have already been severely fragmented, and in the near future, the degree of fragmentation will significantly rise.<ref>{{Cite journal |last1=Templeton |first1=Alan R. |last2=Shaw |first2=Kerry |last3=Routman |first3=Eric |last4=Davis |first4=Scott K. |date=1990 |title=The Genetic Consequences of Habitat Fragmentation |url=https://www.jstor.org/stable/2399621 |journal=Annals of the Missouri Botanical Garden |volume=77 |issue=1 |pages=13–27 |doi=10.2307/2399621 |jstor=2399621 |bibcode=1990AnMBG..77...13T |issn=0026-6493}}</ref> After intensive clearing, the separate fragments tend to be very small islands isolated from each other by cropland, pasture, pavement, or even barren land. The latter is often the result of [[slash and burn]] farming in [[tropical forest]]s.  In the wheat belt of central-western [[New South Wales]], [[Australia]], 90% of the native vegetation has been cleared and over 99% of the [[tall grass prairie]] of [[North America]] has been cleared, resulting in extreme habitat fragmentation.

=== Endogenous vs. exogenous  ===
The two types of processes that can lead to habitat fragmentation are known as endogenous processes and exogenous processes. Endogenous is a process that develops as a part of species biology so they typically include changes in biology, behavior, and interactions within or between species. Endogenous threats can result in changes to breeding patterns or migration patterns and are often triggered by exogenous processes. Exogenous processes are independent of species biology and can include habitat degradation, habitat subdivision or habitat isolation. These processes can have a substantial impact on endogenous processes by fundamentally altering species behavior. Habitat subdivision or isolation can lead to changes in dispersal or movement of species including changes to seasonal migration. These changes can lead to a decrease in a density of species, increased competition or even increased predation.<ref>{{cite journal|last1=Fischer|first1=Joern|last2=Lindenmayer|first2=David B.|date=February 7, 2007|title=Landscape Modification and Habitat Fragmentation: A synthesis|journal=Global Ecology and Biogeography|volume=16|issue=3|pages=265–280|doi=10.1111/j.1466-8238.2007.00287.x|bibcode=2007GloEB..16..265F |ref=1|doi-access=free}}</ref>