Editing Habitat fragmentation (section)

===Informed conservation===
Habitat fragmentation is often a cause of species becoming [[threatened]] or [[endangered]].<ref>{{Cite journal|last1=Crooks|first1=Kevin R.|last2=Burdett|first2=Christopher L.|last3=Theobald|first3=David M.|last4=King|first4=Sarah R. B.|last5=Di Marco|first5=Moreno|last6=Rondinini|first6=Carlo|last7=Boitani|first7=Luigi|date=2017-07-18|title=Quantification of habitat fragmentation reveals extinction risk in terrestrial mammals|journal=Proceedings of the National Academy of Sciences|language=en|volume=114|issue=29|pages=7635–7640|doi=10.1073/pnas.1705769114|issn=0027-8424|pmc=5530695|pmid=28673992|bibcode=2017PNAS..114.7635C |doi-access=free}}</ref> The existence of viable habitat is critical to the survival of any species, and in many cases, the fragmentation of any remaining habitat can lead to difficult decisions for conservation biologists. Given a limited amount of resources available for conservation is it preferable to protect the existing isolated patches of habitat or to buy back land to get the largest possible contiguous piece of land. In rare cases, a [[conservation reliant species]] may gain some measure of disease protection by being distributed in isolated habitats, and when controlled for overall habitat loss some studies have shown a positive relationship between species richness and fragmentation; this phenomenon has been called the habitat amount hypothesis, though the validity of this claim has been disputed.<ref name="Fahrig2013" /><ref>{{Cite journal|last=Hanski|first=Ilkka|date=May 2015|editor-last=Triantis|editor-first=Kostas|title=Habitat fragmentation and species richness|journal=Journal of Biogeography|language=en|volume=42|issue=5|pages=989–993|doi=10.1111/jbi.12478|bibcode=2015JBiog..42..989H |s2cid=84220990 |doi-access=}}</ref> The ongoing debate of what size fragments are most relevant for conservation is often referred to as [[SLOSS debate|SLOSS]] (Single Large or Several Small). Habitat loss in a biodiversity hotspot can result in a localized extinction crisis, generally speaking habitat loss in a hotspot location can be a good indicator or predictor of the number of threatened and extinct endemic species.<ref>{{Cite journal |last1=Brooks |first1=Thomas M. |last2=Mittermeier |first2=Russell A. |last3=Mittermeier |first3=Cristina G. |last4=da Fonseca |first4=Gustavo A. B. |last5=Rylands |first5=Anthony B. |last6=Konstant |first6=William R. |last7=Flick |first7=Penny |last8=Pilgrim |first8=John |last9=Oldfield |first9=Sara |last10=Magin |first10=Georgina |last11=Hilton-Taylor |first11=Craig |date=August 2002 |title=Habitat Loss and Extinction in the Hotspots of Biodiversity |url=https://doi.org/10.1046/j.1523-1739.2002.00530.x |journal=Conservation Biology |volume=16 |issue=4 |pages=909–923 |doi=10.1046/j.1523-1739.2002.00530.x |bibcode=2002ConBi..16..909B |s2cid=44009934 |issn=0888-8892|url-access=subscription }}</ref>

One solution to the problem of habitat fragmentation is to link the fragments by preserving or planting [[Habitat corridor|corridors]] of native vegetation. In some cases, a bridge or underpass may be enough to join two fragments.<ref>{{cite web|title=Wildlife Crossings: Animals survive with bridges and tunnels|url=http://www.wilderutopia.com/environment/wildlife/wildlife-crossings-animals-survive-bridges-tunnels/|publisher=Wilder Eutopia|access-date=19 December 2017|date=2013-05-19}}</ref> This has the potential to mitigate the problem of isolation but not the loss of interior habitat. Wildlife corridors can help animals to move and occupy new areas when food sources or other natural resources are lacking in their core habitat, and animals can find new mates in neighbouring regions so that [[genetic diversity]] can increase. Species that relocate seasonally can do so more safely and effectively when it does not interfere with human development barriers.

Due to the continuous expansion of urban landscapes, current research is looking at [[green roof]]s being possible vectors of habitat corridors.  A recent study has found that green roofs are beneficial in connecting the habitats of arthropods, specifically bees and weevils.<ref>{{Cite journal |last1=Braaker |first1=S. |last2=Ghazoul |first2=J. |last3=Obrist |first3=M. K. |last4=Moretti |first4=M. |date=April 2014 |title=Habitat connectivity shapes urban arthropod communities: the key role of green roofs |url=http://dx.doi.org/10.1890/13-0705.1 |journal=Ecology |volume=95 |issue=4 |pages=1010–1021 |doi=10.1890/13-0705.1 |pmid=24933819 |bibcode=2014Ecol...95.1010B |s2cid=41070926 |issn=0012-9658}}</ref>

Another mitigation measure is the enlargement of small remnants to increase the amount of interior habitat. This may be impractical since developed land is often more expensive and could require significant time and effort to restore.

The best solution is generally dependent on the particular species or ecosystem that is being considered. More mobile species, like most birds, do not need connected habitat while some smaller animals, like rodents, may be more exposed to predation in open land. These questions generally fall under the headings of [[metapopulation]]s [[island biogeography]].