Editing Species reintroduction (section)

==Successes and failures==
[[File:Reem-Lavan001.jpg|thumb|[[Arabian oryx reintroduction|Arabian oryx were reintroduced]] to Oman and Israel in the 20th century.]]
Reintroduction biology is a relatively young discipline and continues to be a work in progress.  No strict and accepted definition of reintroduction success exists, but it has been proposed that the criteria widely used to assess the conservation status of endangered taxa, such as the [[IUCN Red List]] criteria, should be used to assess reintroduction success.<ref name="Robert 2015">{{cite journal |vauthors=Robert A, Colas B, Guigon I, Kerbiriou C, Mihoub JB, Saint-Jalme M, Sarrazin F |year=2015 |title=Defining reintroduction success using IUCN criteria for threatened species: a demographic assessment |journal=Animal Conservation |volume=18 |issue=5| pages=397–406| doi=10.1111/acv.12188|bibcode=2015AnCon..18..397R | s2cid=85603026}}</ref> Successful reintroduction programs should yield viable and self-sustainable populations in the long-term. The IUCN/SSC Re-introduction Specialist Group & Environment Agency, in their 2011 Global Re-introduction Perspectives, compiled reintroduction case studies from around the world.<ref name="iucnsscrsg.org">Soorae, P. S. (ed.) (2011). Global Re-introduction Perspectives: 2011. More case studies from around the globe. Gland, Switzerland: IUCN/SSC Re-introduction Specialist Group and Abu Dhabi, UAE: Environment Agency-Abu Dhabi. xiv + 250 pp.SBN: 978-2-8317-1432-5 https://portals.iucn.org/library/sites/library/files/documents/2011-073.pdf</ref> 184 case studies were reported on a range of species which included [[invertebrate]]s, [[fish]], [[amphibian]]s, [[reptile]]s, [[bird]]s, [[mammal]]s, and [[plant]]s. Assessments from all of the studies included goals, success indicators, project summary, major difficulties faced, major lessons learned, and success of project with reasons for success or failure. A similar assessment focused solely on plants found high rates of success for rare species reintroductions.<ref>{{Cite journal |last1=Albrecht |first1=Matthew A. |last2=Guerrant Jr. |first2=Edward O. |last3=Maschinski |first3=Joyce |last4=Kennedy |first4=Kathryn L. |date=2011-11-01 |title=A long-term view of rare plant reintroduction |journal=Biological Conservation |volume=144 |issue=11 |pages=2557–2558 |doi=10.1016/j.biocon.2011.07.021 |bibcode=2011BCons.144.2557A }}</ref> An analysis of data from the Center for Plant Conservation International Reintroduction Registry found that, for the 49 cases where data were available, 92% of the reintroduced plant populations survived two years.
The [[Siberian tiger]] population has rebounded from 40 individuals in the 1940s to around 500 in 2007. The Siberian tiger population is now the largest un-fragmented tiger population in the world.<ref>Rietbergen, Jennifer Building a Sustainable Future WWF International 2008</ref> Yet, a high proportion of translocations and reintroductions have not been successful in establishing viable populations.<ref name="Kleiman 1989">{{cite journal |year=1989 |title=Reintroduction of captive mammals for conservation. Guidelines for reintroducing endangered species into the wild |journal=BioScience |volume=39 |issue=3 |pages=152–161 |doi=10.2307/1311025 |last1=Kleiman |first1=D. G. |jstor=1311025}}</ref>
For instance, in China reintroduction of captive Giant Pandas have had mixed effects. The initial pandas released from captivity all died quickly after reintroduction.<ref>{{Cite web|url=https://www.pandasinternational.org/program-areas-2/reintroduction-program/reintroduction-program-2006/ |title=Reintroduction Program – 2006 |website=Pandas International|language=en-US|access-date=2017-06-03}}</ref> Even now that they have improved their ability to reintroduce pandas, concern remains over how well the captive-bred pandas will fare with their wild relatives.<ref>{{Cite news|title=New Video Shows Returning Pandas to the Wild Actually Works |date=19 April 2017 |url=http://news.nationalgeographic.com/2017/04/giant-pandas-china-video-reintroduction/|access-date=2017-06-03|archive-url=https://web.archive.org/web/20170422102737/http://news.nationalgeographic.com/2017/04/giant-pandas-china-video-reintroduction/ |archive-date=April 22, 2017}}</ref>

Many factors can attribute to the success or failure of a reintroduction.  Predators, food, pathogens, competitors, and weather can all affect a reintroduced population's ability to grow, survive, and reproduce. The number of animals reintroduced in an attempt should also vary with factors such as social behavior, expected rates of predation, and density in the wild.<ref>{{Cite journal |last1=Wimberger |first1=Kirsten |last2=Downs |first2=Colleen T. |last3=Perrin |first3=Mike R. |date=2009-10-01 |title=Two Unsuccessful Reintroduction Attempts of Rock Hyraxes (Procavia capensis) into a Reserve in the KwaZulu-Natal Province, South Africa |journal=South African Journal of Wildlife Research |volume=39 |issue=2 |pages=192–201 |doi=10.3957/056.039.0213 |s2cid=85997109 |issn=0379-4369}}</ref> Animals raised in captivity may experience stress during captivity or translocation, which can weaken their immune systems.<ref name="Stamps 2007" />
The IUCN reintroduction guidelines emphasize the need for an assessment of the availability of suitable habitat as a key component of reintroduction planning.<ref name="SSC Re-introduction Specialist Group 1995">Prepared by the SSC Re-introduction Specialist Group (May 1995) IUCN/SSC Guidelines for Re-Introductions http://www.iucnsscrsg.org</ref>  Poor assessment of the release site can increase the chances that the species will reject the site and perhaps move to a less suitable environment. This can decrease the species fitness and thus decrease chances for survival.<ref name="Stamps 2007">{{cite journal | last1 = Stamps | first1 = J.A. | last2 = Swaisgood | first2 = R.R  | year = 2007 | title = Someplace like home: Experience, Habitat selection and Conservation Biology | journal = Applied Animal Behaviour Science | volume = 102 | issue = 3–4| pages = 392–409 | doi = 10.1016/j.applanim.2006.05.038 }}</ref> They state that restoration of the original habitat and amelioration of causes of extinction must be explored and considered as essential conditions for these projects. Unfortunately, the monitoring period that should follow reintroductions often remains neglected.<ref>Sarrazin, F. Barbault, R. (November 1996).  Reintroduction: Challenges and Lessons for Basic Ecology Elsevier Science Volume 11 No. 11</ref>