Species reintroduction

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A Przewalski's horse being released into the wild in Mongolia, as part of the Return of the Wild Horses project.

Species reintroduction is the deliberate release of a species into the wild, from captivity or other areas where the organism is capable of survival.<ref name="Campbell-Palmer 2010">Template:Cite journal</ref> The goal of species reintroduction is to establish a healthy, genetically diverse, self-sustaining population to an area where it has been extirpated, or to augment an existing population.<ref name=":0">Template:Cite book</ref> Species that may be eligible for reintroduction are typically threatened or endangered in the wild. However, reintroduction of a species can also be for pest control; for example, wolves being reintroduced to a wild area to curb an overpopulation of deer. Because reintroduction may involve returning native species to localities where they had been extirpated, some prefer the term "reestablishment".<ref name="Campbell-Palmer 2010"/>

Humans have been reintroducing species for food and pest control for thousands of years. However, the practice of reintroducing for conservation is much younger, starting in the 20th century.<ref name="Seddon 2007">Template:Cite journal</ref>

Methods for sourcing individuals

There are a variety of approaches to species reintroduction. The optimal strategy will depend on the biology of the organism.<ref name="IUCN 2017 Guidelines">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The first matter to address when beginning a species reintroduction is whether to source individuals in situ, from wild populations, or ex situ, from captivity in a zoo or botanic garden, for example.

In situ sourcing

In situ sourcing for restorations involves moving individuals from an existing wild population to a new site where the species was formerly extirpated. Ideally, populations should be sourced in situ when possible due to the numerous risks associated with reintroducing organisms from captive populations to the wild.<ref name="IUCN 2017 Ex Situ">Template:Cite journal</ref> To ensure that reintroduced populations have the best chance of surviving and reproducing, individuals should be sourced from populations that genetically and ecologically resemble the recipient population.<ref name=":1" /> Generally, sourcing from populations with similar environmental conditions to the reintroduction site will maximize the chance that reintroduced individuals are well adapted to the habitat of the reintroduction site otherwise there are possibilities that they will not take to their environment. .<ref name="Houde et al 2017">Template:Cite journal</ref><ref name=":1">Template:Cite journal</ref>

One consideration for in situ sourcing is at which life stage the organisms should be collected, transported, and reintroduced. For instance, with plants, it is often ideal to transport them as seeds as they have the best chance of surviving translocation at this stage. However, some plants are difficult to establish as seed and may need to be translocated as juveniles or adults.<ref name="IUCN 2017 Guidelines"/>

Ex situ sourcing

In situations where in situ collection of individuals is not feasible, such as for rare and endangered species with too few individuals existing in the wild, ex situ collection is possible. Ex situ collection methods allow storage of individuals that have high potential for reintroduction. Storage examples include germplasm stored in seed banks, sperm and egg banks, cryopreservation, and tissue culture.<ref name="IUCN 2017 Ex Situ"/> Methods that allow for storage of a high numbers of individuals also aim to maximize genetic diversity. Stored materials generally have long lifespans in storage, but some species do lose viability when stored as seed.<ref name="Walters 2005">Template:Cite journal</ref> Tissue culture and cryopreservation techniques have only been perfected for a few species.<ref name="Engelmann 2011">Template:Cite journal</ref>

Organisms may also be kept in living collections in captivity. Living collections are more costly than storing germplasm and hence can support only a fraction of the individuals that ex situ sourcing can.<ref name="IUCN 2017 Ex Situ"/> Risk increases when sourcing individuals to add to living collections. Loss of genetic diversity is a concern because fewer individuals stored.<ref>Template:Cite journal</ref> Individuals may also become genetically adapted to captivity, which often adversely affects the reproductive fitness of individuals. Adaptation to captivity may make individuals less suitable for reintroduction to the wild. Thus, efforts should be made to replicate wild conditions and minimize time spent in captivity whenever possible.<ref name="Frankham 2008">Template:Cite journal</ref>

Successes and failures

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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">Template:Cite journal</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 invertebrates, fish, amphibians, reptiles, birds, mammals, and plants. 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>Template:Cite journal</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">Template:Cite journal</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>{{#invoke:citation/CS1|citation |CitationClass=web }}</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>Template:Cite news</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>Template:Cite journal</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">Template:Cite journal</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>

Genetic considerations

When a species has been extirpated from a site where it previously existed, individuals that will comprise the reintroduced population must be sourced from wild or captive populations. When sourcing individuals for reintroduction, it is important to consider local adaptation, adaptation to captivity (for ex situ conservation), the possibility of inbreeding depression and outbreeding depression, and taxonomy, ecology, and genetic diversity of the source population.<ref name=":0" /> Reintroduced populations experience increased vulnerability to influences of drift, selection, and gene flow evolutionary processes due to their small sizes, climatic and ecological differences between source and native habitats, and presence of other mating-compatible populations.<ref name="Frankham 2008" /><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

If the species slated for reintroduction is rare in the wild, it is likely to have unusually low population numbers, and care should be taken to avoid inbreeding and inbreeding depression.<ref name=":0" /> Inbreeding can change the frequency of allele distribution in a population, and potentially result in a change to crucial genetic diversity.<ref name=":0" /> Additionally, outbreeding depression can occur if a reintroduced population can hybridize with existing populations in the wild, which can result in offspring with reduced fitness, and less adaptation to local conditions. To minimize both, practitioners should source for individuals in a way that captures as much genetic diversity as possible, and attempt to match source site conditions to local site conditions as much as possible.<ref name=":0" />

Capturing as much genetic diversity as possible, measured as heterozygosity, is suggested in species reintroductions.<ref name=":0" /> Some protocols suggest sourcing approximately 30 individuals from a population will capture 95% of the genetic diversity.<ref name=":0" /> Maintaining genetic diversity in the recipient population is crucial to avoiding the loss of essential local adaptations, minimizing inbreeding depression, and maximizing fitness of the reintroduced population.

Ecological similarity

Plants or animals that undergo reintroduction may exhibit reduced fitness if they are not sufficiently adapted to local environmental conditions. Therefore, researchers should consider ecological and environmental similarity of source and recipient sites when selecting populations for reintroduction. Environmental factors to consider include climate and soil traits (pH, percent clay, silt and sand, percent combustion carbon, percent combustion nitrogen, concentration of Ca, Na, Mg, P, K).<ref name=":1" /> Historically, sourcing plant material for reintroductions has followed the rule "local is best," as the best way to preserve local adaptations, with individuals for reintroductions selected from the most geographically proximate population.<ref>Template:Cite journal</ref> However, geographic distance was shown in a common garden experiment to be an insufficient predictor of fitness.<ref name=":1" /> Additionally, projected climatic shifts induced by climate change have led to the development of new seed sourcing protocols that aim to source seeds that are best adapted to project climate conditions.<ref>Template:Cite journal</ref> Conservation agencies have developed seed transfer zones that serve as guidelines for how far plant material can be transported before it will perform poorly.<ref>Template:Cite book</ref> Seed transfer zones take into account proximity, ecological conditions, and climatic conditions in order to predict how plant performance will vary from one zone to the next. A study of the reintroduction of Castilleja levisecta found that the source populations most physically near the reintroduction site performed the poorest in a field experiment, while those from the source population whose ecological conditions most closely matched the reintroduction site performed best, demonstrating the importance of matching the evolved adaptations of a population to the conditions at the reintroduction site.<ref>Template:Cite journal</ref>

Adaptation to captivity

Some reintroduction programs use plants or animals from captive populations to form a reintroduced population.<ref name=":0" /> When reintroducing individuals from a captive population to the wild, there is a risk that they have adapted to captivity due to differential selection of genotypes in captivity versus the wild. The genetic basis of this adaptation is selection of rare, recessive alleles that are deleterious in the wild but preferred in captivity.<ref name="Frankham 2008" /> Consequently, animals adapted to captivity show reduced stress tolerance, increased tameness, and loss of local adaptations.<ref>Template:Cite journal</ref> Plants also can show adaptations to captivity through changes in drought tolerance, nutrient requirements, and seed dormancy requirements.<ref>Template:Cite journal</ref> Extent of adaptation is directly related to intensity of selection, genetic diversity, effective population size and number of generations in captivity. Characteristics selected for in captivity are overwhelmingly disadvantageous in the wild, so such adaptations can lead to reduced fitness following reintroduction. Reintroduction projects that introduce wild animals generally experience higher success rates than those that use captive-bred animals.<ref name="Frankham 2008" /> Genetic adaptation to captivity can be minimized through management methods: by maximizing generation length and number of new individuals added to the captive population; minimizing effective population size, number of generations spent in captivity, and selection pressure; and reducing genetic diversity by fragmenting the population.<ref name=":0" /><ref name="Frankham 2008" /> For plants, minimizing adaptation to captivity is usually achieved by sourcing plant material from a seed bank, where individuals are preserved as wild-collected seeds, and have not had the chance to adapt to conditions in captivity. However, this method is only plausible for plants with seed dormancy.<ref name="Frankham 2008" />

Genetic trade-offs

In reintroductions from captivity, translocation of animals from captivity to the wild has implications for both captive and wild populations. Reintroduction of genetically valuable animals from captivity improves genetic diversity of reintroduced populations while depleting captive populations; conversely, genetically valuable captive-bred animals may be closely related to individuals in the wild and thus increase risk of inbreeding depression if reintroduced. Increasing genetic diversity is favored with removal of genetically overrepresented individuals from captive populations and addition of animals with low genetic relatedness to the wild.<ref>Template:Cite journal</ref><ref name=":3">Template:Cite book</ref> However, in practice, initial reintroduction of individuals with low genetic value to the captive population is recommended to allow for genetic assessment before translocation of valuable individuals.<ref name=":3" />

Improving research techniques

A cooperative approach to reintroduction by ecologists and biologists could improve research techniques. For both preparation and monitoring of reintroductions, increasing contacts between academic population biologists and wildlife managers is encouraged within the Survival Species Commission and the IUCN. The IUCN states that a re-introduction requires a multidisciplinary approach involving a team of persons drawn from a variety of backgrounds.<ref name="SSC Re-introduction Specialist Group 1995"/> A survey by Wolf et al. in 1998 indicated that 64% of reintroduction projects have used subjective opinion to assess habitat quality.<ref name="Stamps 2007"/> This means that most reintroduction evaluation has been based on human anecdotal evidence and not enough has been based on statistical findings. Seddon et al. (2007) suggest that researchers contemplating future reintroductions should specify goals, overall ecological purpose, and inherent technical and biological limitations of a given reintroduction, and planning and evaluation processes should incorporate both experimental and modeling approaches.<ref name="Seddon 2007" />

Monitoring the health of individuals, as well as the survival, is important; both before and after the reintroduction. Intervention may be necessary if the situation proves unfavorable.<ref name="SSC Re-introduction Specialist Group 1995"/> Population dynamics models that integrate demographic parameters and behavioral data recorded in the field can lead to simulations and tests of a priori hypotheses. Using previous results to design further decisions and experiments is a central concept of adaptive management. In other words, learning by doing can help in future projects. Population ecologists should therefore collaborate with biologists, ecologists, and wildlife management to improve reintroduction programs.<ref name="bgci.org">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Genetic monitoring

For reintroduced populations to successfully establish and maximize reproductive fitness, practitioners should perform genetic tests to select which individuals will be the founders of reintroduced populations and to continue monitoring populations post-reintroduction.<ref name="IUCN 2017 Guidelines" /> A number of methods are available to measure the genetic relatedness between and variation among individuals within populations. Common genetic diversity assessment tools include microsatellite markers, mitochondrial DNA analyses, alloenzymes, and amplified fragment length polymorphism markers.<ref>Template:Cite journal</ref> Post-reintroduction, genetic monitoring tools can be used to obtain data such as population abundance, effective population size, and population structure, and can also be used to identify instances of inbreeding within reintroduced populations or hybridization with existing populations that are genetically compatible. Long-term genetic monitoring is recommended post-reintroduction to track changes in genetic diversity of the reintroduced population and determine success of a reintroduction program. Adverse genetic changes such as loss of heterozygosity may indicate management intervention, such as population supplementation, is necessary for survival of the reintroduced population.<ref name="Haye 877–892">Template:Cite journal</ref><ref>Template:Cite journal</ref><ref name="Mowry 196–206">Template:Cite journal</ref>

Re-introduction Specialist Group (RSG)

The RSG is a network of specialists whose aim is to combat the ongoing and massive loss of biodiversity by using re-introductions as a responsible tool for the management and restoration of biodiversity. It does this by actively developing and promoting sound inter-disciplinary scientific information, policy, and practice to establish viable wild populations in their natural habitats. The role of the RSG is to promote the re-establishment of viable populations in the wild of animals and plants. The need for this role was felt due to the increased demand from re-introduction practitioners, the global conservation community and increase in re-introduction projects worldwide.

Increasing numbers of animal and plant species are becoming rare, or even extinct in the wild. In an attempt to re-establish populations, species can – in some instances – be re-introduced into an area, either through translocation from existing wild populations, or by re-introducing captive-bred animals or artificially propagated plants.

Reintroduction programs

Africa

• Addax in Morocco and Tunisia,<ref name="iucn">Template:Cite iucn</ref> Chad<ref>Template:Cite news</ref>
• African bush elephant into Samara Private Game Reserve in Eastern Cape, South Africa<ref>Template:Cite news</ref>
• African leopard into Majete Wildlife Reserve, Malawi<ref>Template:Cite news</ref><ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• African spurred tortoise in Senegal<ref>Template:Cite news</ref>
• African wild dog into Gorongosa National Park in Mozambique<ref>Template:Cite news</ref><ref>Template:Cite news</ref> and Lekedi Park, Gabon (successful)<ref>Template:Cite news</ref> and Majete Wildlife Reserve in Malawi<ref>{{#invoke:citation/CS1|citation

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• Angolan giraffe into Iona National Park in Angola(successful)<ref>Template:Cite news</ref><ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• Black rhinoceros in Malawi, Zambia, Botswana,<ref>Template:Cite news</ref><ref>Template:Cite news</ref> Rwanda<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> (successful) and Chad<ref>Template:Cite news</ref> (ongoing), Gonarezhou National Park in Zimbabwe,<ref>Template:Cite news</ref><ref>Template:Cite news</ref> Zinave National Park in Mozambique<ref>Template:Cite news</ref>

• Chimpanzee in the Douala-Edea Wildlife Reserve in Cameroon<ref>Template:Cite news</ref>
• Cuvier's gazelle in Jebel Serj National Park, Tunisia<ref>{{#invoke:citation/CS1|citation

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• Dorcas gazelle in Ferlo Nord Wildlife Reserve, Senegal<ref>Template:Cite news</ref><ref>{{#invoke:citation/CS1|citation

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• Grevy's zebra in Djibouti<ref>Template:Cite news</ref>
• Ground pangolin into the Phinda Private Game Reserve in KwaZulu-Natal, South Africa<ref>{{#invoke:citation/CS1|citation

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• Lion to Akagera National Park of Rwanda<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite news</ref> and Majete Wildlife Reserve and Liwonde National Park of Malawi<ref>Template:Cite news</ref><ref>Template:Cite news</ref>

• Mandrill into Lékédi Park, Gabon<ref>Template:Cite journal</ref>
• Mhorr gazelle (subspecies of Dama gazelle) into Safia Reserve in Southern Morocco (failure and ongoing)<ref>Template:Cite journal</ref>
• North African ostrich in Morocco, Nigeria, Niger and Tunisia (ongoing)
• Plains zebra into Kitulo National Park in southern Tanzania<ref>Template:Cite news</ref> and Nsumbu National Park in northern Zambia<ref>Template:Cite news</ref>
• Reticulated giraffe in Mount Kenya, Kenya<ref>Template:Cite news</ref>
• Scimitar oryx in Chad<ref>Template:Cite news</ref><ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• Southern white rhinoceros in Kenya, Uganda, Zambia (successful)Template:Citation needed and Garamba National Park, DR Congo,<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> Akagera National Park, Rwanda<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• South African cheetah in Eswatini and Malawi (successful)<ref>Template:Cite news</ref>
• Spotted hyena to Zinave National Park<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> and Gorongosa National Park (planned)<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> in Mozambique

• West African crocodile into Morocco<ref>{{#invoke:citation/CS1|citation

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• West African giraffe to Gadabedji Reserve, Niger<ref>{{#invoke:citation/CS1|citation

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Asia

• Amur leopard in Russia (planned)<ref>{{#invoke:citation/CS1|citation

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• Asian elephant into Doi Pha Muang Wildlife Sanctuary, Thailand<ref>Template:Cite news</ref>
• Asian giant tortoise in Bangladesh<ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• Asiatic Lion Reintroduction Project of Asiatic lion to Kuno Wildlife Sanctuary from their only home presently in the world at Gir Forest National Park. Kuno Wildlife Sanctuary is the chosen site for re-introducing and establishing the world's second completely separate population of the wild free ranging Asiatic lions in the state of Madhya Pradesh. It was decided to re-introduce the Asiatic lion in Kumbhalgarh Wildlife Sanctuary in Rajasthan. Some will be reintroduced in two locations in Gujarat.<ref name="Seddon 2007" />
• Bengal tiger in Sariska Tiger Reserve of Rajasthan, India<ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• Blackbuck to Pakistan (ongoing)<ref>Template:Cite journal</ref>
• Bornean orangutan in East Kalimantan, Indonesia<ref>See Borneo Orangutan Survival</ref>
• Bactrian deer (subspecies of Central Asian red deer) into Altyn Emel National Park in Kazakhstan<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> and Badai Tugai Nature Reserve in Uzbekistan<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Burmese star tortoise in Myanmar<ref>Template:Cite news</ref>
• Cheetah reintroduction in India is a project to reintroduce the cheetah in India. The Asiatic cheetah became extinct in India in 1947 when Maharaja of Surguja hunted the last three in the state of Rewa in central India. It was officially declared extinct in 1952 by the Indian government. Plans are going on to reintroduce the cheetah to two site in Madhya Pradesh (Kuno Wildlife Sanctuary and Nauradehi Wildlife Sanctuary) and in Rajasthan's Shahgarh Landscape. Cheetahs are being acclimated to Kuno National Park.<ref>{{#invoke:citation/CS1|citation

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• Chinese alligator into Yancheng Biosphere Reserve, Jiangsu Province, China<ref>{{#invoke:citation/CS1|citation

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• Crested ibis at Upo Wetland, South Korea<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> and Sado, Japan<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Gaur into Bandhavgarh National Park in Madhya Pradesh, India<ref>{{#invoke:citation/CS1|citation

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• Formosan sika deer into Kenting National Park, Taiwan<ref>{{#invoke:citation/CS1|citation

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• Gharial at the Hastinapur Wildlife Sanctuary in Uttar Pradesh, India<ref>{{#invoke:citation/CS1|citation

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• Indian rhinoceros to Lal Suhanra National Park, Pakistan (failure)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> and Dudhwa National Park in India<ref>Template:Cite book</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and Jim Corbett National Park (planning)<ref>Template:Cite news</ref>

• Korean fox (subspecies of red fox) in Sobaeksan National Park, South Korea (ongoing)<ref>{{#invoke:citation/CS1|citation

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• Lar gibbon to Phuket, Thailand<ref>Template:Cite journal</ref>
• Magnolia sinica to China<ref>Template:Cite book</ref>
• Oriental stork in South Korea<ref>Template:Cite journal</ref>
• Père David's deer in China (successful)
• Persian leopard in European Russia (ongoing)
• Pileated gibbon into the protected forests of the Angkor, Cambodia<ref>{{#invoke:citation/CS1|citation

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• Przewalski's horse in Mongolia, China, and Kazakhstan (ongoing)<ref>Template:Cite iucn</ref><ref>{{#invoke:citation/CS1|citation

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• Pygmy hogs into Sonai Rupai Wildlife Sanctuary in Assam, India (successful)<ref>{{#invoke:citation/CS1|citation

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• Sarus cranes in Thailand (ongoing)
• Short-tailed albatross in Japan (successful)<ref>ACAP Breeding Site No. 65. Torishima, where Short-tailed Albatrosses have survived both feather collectors and an active volcano</ref>
• Siamese crocodile into Cát Tiên National Park of Vietnam<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Siberian Tiger Re-population Project was proposed in 2009 to reintroduce Siberian tigers back to their former lands and including the former ranges in Central Asia once inhabited by their closest relatives, the Caspian tiger. In 2010, two pairs of Siberian tigers, exchanged for Persian leopards to southwestern Russia, were set to be reintroduced in Iran's Miankaleh Peninsula. Currently, the big cats (one of them had died) are being held in captivity in Eram zoo. Siberian tigers were also proposed to be reintroduced to a suitable habitat near the international river of Amu Darya in Central Asia and near the Ili River delta in Kazakhstan. A rewilding project at the Pleistocene Park, part of the re-population project was proposed back in 2005.<ref>{{#invoke:citation/CS1|citation

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• South China tiger – captive tigers being re-wilded in Laohu Valley Reserve in the Free State province of South Africa under Save China's Tigers programme, will be eventually released back into the wilderness of China.
• Sumatran orangutan at Bukit Tigapuluh National Park in Jambi and Jantho Pine Forest Nature Reserve in Aceh, Sumatra, Indonesia<ref>{{#invoke:citation/CS1|citation

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• Turkmenian kulan in Kazakhstan (ongoing) and Uzbekistan (successful)
• Ussuri black bear (subspecies of Asian black bear) in Jirisan National Park, South Korea (ongoing)<ref>{{#invoke:citation/CS1|citation

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• Water deer in Shanghai, China (successful)<ref>Template:Cite news</ref>
• Wild water buffalo in Chitwan National Park of Nepal<ref>Template:Cite journal</ref> and in Kanha National Park of Madhya Pradesh, India<ref>Template:Cite news</ref>

Middle East

• Arabian gazelle in Saudi Arabia<ref name=":2">{{#invoke:citation/CS1|citation

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• Arabian sand gazelle in Saudi Arabia<ref>Template:Cite journal</ref>
• Arabian oryx in the Sultanate of Oman (successful), United Arab Emirates (successful), Israel (successful), Saudi Arabia (ongoing), Jordan (ongoing)<ref>Template:Cite journal</ref><ref name=":2" /><ref>IUCN SSC Antelope Specialist Group. 2017. Oryx leucoryx. The IUCN Red List of Threatened Species 2017: e.T15569A50191626. https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T15569A50191626.en.</ref>
• Egyptian vulture in Israel (ongoing)<ref>Template:Cite journal</ref>
• Eurasian griffon vulture in Israel (ongoing)<ref>Template:Cite journal</ref>
• Houbara bustard in Jordan (ongoing)<ref>{{#invoke:citation/CS1|citation

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• Kurdistan spotted newt in Western Iran (successful)<ref>Sharifi M.. Vaissi S.. 2014. Captive breeding and trial reintroduction of the Endangered yellow-spotted mountain newt Neurergus microspilotus in western Iran (pdf). Endanger Species Res 23. Vol. 23: pp.159–166. doi: 10.3354/esr00552. Retrieved on March 31, 2017</ref>
• Lanner falcon in Israel (successful)<ref>Hatzofe, O. (2001). Reintroduction of raptors to Ramat HaNadiv. Wings over Africa. The International Center for the Study of Bird Migration, Latrun, Israel, 190-202.</ref>
• North African ostrich in Israel (failure) and Saudi Arabia (successful)<ref>Template:Cite news</ref><ref>Template:Cite journal</ref>
• Nubian ibex in Israel (successful), Jordan (successful), Saudi Arabia (ongoing), and Lebanon (ongoing)<ref>Template:Cite book</ref><ref name=":2" /><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite journal</ref>

• Paper reed in Israel's Hula Valley (successful)<ref>Template:Cite journal</ref>
• Persian fallow deer in Israel (successful)<ref>{{#invoke:citation/CS1|citation

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• Persian onager in Saudi Arabia (successful) and Israel (successful)<ref>{{#invoke:citation/CS1|citation

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• Red deer to Armenia - A programme was announced in 2013 to reintroduce the red deer to Armenia. 4 males and 11 females of the species will be purchased and transported to a breeding centre at Dilijan National Park. The World Wildlife Fund Germany and Orange Armenia have provided the funds for the project.
• Roe deer in Israel (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite journal</ref>

• Yarkon bleak fish in Israel (successful)<ref>Goren, M. 2014. Acanthobrama telavivensis. The IUCN Red List of Threatened Species 2014: e.T61249A19009597. https://dx.doi.org/10.2305/IUCN.UK.2014-1.RLTS.T61249A19009597.en.</ref>
• Arabian Leopard in Israel (ongoing)<ref>Template:Cite journal</ref> Yotvata Hai-Bar Nature Reserve is working on reintroduction.
• Persian Leopard in Israel (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> The Ramat Gan Safari and the Yotvata Hai-Bar Nature Reserve are working on reintroduction.

Europe

File:Cricetus-cricetus-Vienna-2015.JPG

Black-bellied hamster (Cricetus cricetus), also known as European hamster, common hamster

• Alpine ibex in the French, Italian and Swiss Alps (successful)
• Alpine marmot in the Pyrenees, where it had been extirpated at end of the Pleistocene (successful)<ref>Template:Cite journal</ref>
• Black-bellied hamster in Netherlands and Belgium (successful)<ref name="Haye 877–892"/>
• Black grouse to Derbyshire, England – (ongoing)
• Chequered skipper butterfly to Northamptonshire, England – (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Common crane to Somerset, England – (ongoing)
• Corncrake to Cambridgeshire, England – (ongoing)
• Eurasian brown bear in the Alps (ongoing)<ref>Groff C., Bragalanti N., Rizzoli R., Zanghellini P. (editors), "2012 Bear Report, Forestry and Wildlife Department of the Autonomous Province of Trento", 2013.</ref> and in the Pyrenees (ongoing)
• Eurasian lynx in Switzerland (successful), the United Kingdom (proposed) and other parts of Europe (ongoing)
• European beaver in several countries in Europe (successful)
• European bison in Poland, Belarus (successful), other parts of Europe including Denmark, Spain, Ukraine, Romania, the UK, and others (ongoing)<ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• European black vulture in the Massif Central in France – (successful)
• European mink in Estonia and Spain – (ongoing)<ref>Template:Cite book</ref>
• European wildcat in the Devon and Cornwall in England – (ongoing)
• Heath fritillary butterfly to Essex, England– (successful)
• Glanville fritillary butterfly to Somerset, England – (successful)
• Goitered gazelle in protected areas of Vashlovani in Georgia – (ongoing)<ref>Template:Cite news</ref>
• Golden eagle in Ireland (ongoing)
• Great bustard to Salisbury Plain, England – (ongoing)
• Griffon vulture in the Massif Central, France (successful), Central Apennines, Italy, and Northern and Southern Israel (ongoing)
• Iberian lynx in Portugal (ongoing)
• Lammergeier in the Alps (successful) Switzerland (successful)
• Ladybird spider to Arne RSPB reserve in Dorset, England – (ongoing).<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Large blue butterfly in the South West of England – (successful and ongoing)<ref>Template:Cite journal</ref>
• Lesser kestrel in Spain
• Lesser white-fronted goose in Sweden and Germany (ongoing)
• Narrow-leaved cudweed in Britain<ref>Template:Cite journal</ref>
• Northern bald ibis in Austria, Germany, Italy<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> and Spain<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> (ongoing)

• Northern goshawk – the existing UK population is believed to be derived from a mixture of escaped falconers' birds and deliberate introductions – (successful)
• Osprey to England and Wales – (successful)
• Peregrine falcon in Germany, Poland, Sweden and Norway
• Persian leopard to Caucasus Biosphere Reserve, European Russia<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Pine marten in Wales – (ongoing)<ref>Template:Cite news</ref>
• Przewalski's horse in Ukraine (successful)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Red kite in Ireland<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> Chiltern Hills, Black Isle, Northamptonshire, Dumfries and Galloway, Yorkshire, Perth and Kinross and Gateshead – (successful), and Spain (ongoing)<ref>Template:Cite news</ref>

• Red squirrel to Anglesey, Wales – (successful and ongoing)<ref>Red squirrel conservation, squirrel ecology and grey squirrel management</ref>
• Scots pine to southern England – (unplanned, successful)
• Silver-washed fritillary to Essex, England – (ongoing, locally successful)
• Western swamphen in the Mondego River basin, Portugal (successful)
• White stork to France, Sweden, the Netherlands, Belgium, Switzerland (all successful) and England (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• White-tailed eagle in Ireland (ongoing) and Hebrides, Scotland – (successful), England (ongoing)<ref>Template:Cite news</ref> and Wales (planned – on hold while a suitable site is found)
• Wild boar to several places in Britain – (accidental, successful)

North America

• American bison to El Carmen Nature Reserve<ref>Template:Cite news</ref> and Janos Biosphere Reserve<ref>Template:Cite journal</ref> in Mexico, American Prairie and many National Parks, Wildlife Refuges, and other public lands in the United States, Banff National Park in Canada (Alberta) (successful)<ref>Template:Cite news</ref><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• American flamingo to Anegada, British Virgin Islands (successful)<ref>{{#invoke:citation/CS1|citation

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File:Fisher Reintroduction 2015 at Cispus Learning Center, 065.jpg

A fisher leaps from its holding container and darts off into the Gifford Pinchot National Forest.

• Atlantic puffin to Eastern Egg Rock Island, Maine<ref>Template:Cite news</ref><ref>Template:Cite news</ref>
• Bald eagle to Channel Islands National Park, California<ref name="NPCA"/>
• Black-footed ferret in United States (successful), Canada and Mexico (failure)<ref name="NPCA"/><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Blanding's turtle in Canada<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Blue-and-yellow macaw to Trinidad (successful)<ref>Plair, B.L., Lal, M., Ramadhar, A., and Ramsubage, S. 2013. Status of Blue-and-yellow Macaws

(Ara ararauna) Reintroduced to the Nariva Swamp, Trinidad and Tobago. Living World, Journal of The Trinidad and Tobago Field Naturalists' Club, 2013, 19-28.</ref>

• California condor in United States (California, Arizona, Utah, Oregon) and Mexico (Baja California) (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Canada lynx to Colorado (successful),<ref>Vashon, J. 2016. Lynx canadensis. The IUCN Red List of Threatened Species 2016: e.T12518A101138963. https://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T12518A101138963.en. Accessed on 20 August 2023.</ref> New York (failure)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Chloropyron maritimum in Western United States<ref>Template:Cite journal</ref>
• Cougar to Eastern United States (proposed)<ref>Template:Cite journal</ref>
• Bighorn sheep in Oregon (successful)<ref name="NPCA"/><ref>Template:Cite journal</ref>
• Black-tailed prairie dog in Arizona and New Mexico (successful)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Desert pupfish to Organ Pipe Cactus National Monument, Arizona<ref name="NPCA"/>
• Elk to eastern Kentucky,<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> Great Smoky Mountains National Park, Pennsylvania (Allegheny National Forest), Texas (Big Bend National Park), Arizona, New Mexico, North Carolina and Tennessee (all successful)<ref name="NPCA"/><ref>Template:Cite news</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and to New York (failure)<ref>Template:Cite book</ref>

• Fisher in Washington state (successful)<ref name="NPCA"/><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> (ongoing)

• Geoffroy's spider monkey in Guatemala<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Grey wolf to Yellowstone National Park in Wyoming,<ref name="NPCA"/><ref>Yellowstone National Park, "Wolf Reintroduction Changes Ecosystem", 21 June 2011.</ref> Idaho, Montana, California, Oregon, Washington (successful),<ref name="NPCA"/> Colorado (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Yucatán black howler in Belize<ref>Template:Cite news</ref>
• Mexican wolf in United States (Arizona, New Mexico), and Mexico (Sonora, Chihuahua) (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Musk ox in Alaska (successful)
• North American jaguar to Arizona and New Mexico (proposed)<ref>Template:Cite journal</ref>
• North American river otter in Missouri (successful)<ref name="Mowry 196–206" />
• Pediocactus knowltonii in New Mexico<ref>Template:Cite journal</ref>
• Red wolf in Eastern North Carolina (ongoing), the Gulf Coast (failure), and Great Smoky Mountains National Park (failure)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Ridgway's hawk to areas in the Dominican Republic where it is extirpated<ref name="rhawk">Template:Cite iucn</ref>
• Sargent's cherry palm in Florida (successful)<ref>Template:Cite journal</ref>
• Scarlet macaw to Palenque, Mexico<ref>Template:Cite journal</ref>
• Whooping cranes, including migratory population in the Eastern United States and non-migratory population in Louisiana (ongoing)
• Wild turkey in South Carolina<ref name=postcourier>Template:Cite news</ref><ref name=outdoor>Template:Cite news</ref>
• West Indian manatee in the Grand Cul-de-Sac Marin Bay, Guadeloupe (failure)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Wood bison in Alaska<ref>{{#invoke:citation/CS1|citation

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Oceans and Oceania

• Allocasuarina portuensis in Australia<ref>Template:Cite journal</ref>
• Eastern quoll in Australia (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite news</ref>

• Greater bilby in Arid Recovery Reserve, South Australia and other parts of Australia (successful)<ref>Template:Cite journal</ref>
• Kākāpō to Maungatautari, mainland New Zealand (ongoing)<ref name="MNZ">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Komodo dragon to Australia (proposed)<ref>Template:Cite book</ref>
• Nēnē at Hawaiʻi Volcanoes National Park, Hawaii (ongoing)<ref name="NPCA"/>
• North Island robin to Tiritiri Matangi, Auckland, New Zealand<ref>Template:Cite news</ref>
• Numbat in other areas of Western Australia, Scotia Sanctuary (New South Wales), Yookamura Sanctuary (South Australia)<ref>Template:Cite news</ref>
• Ranunculus prasinus in Tasmania<ref>Template:Cite journal</ref>
• Rutidosis leptorrhynchoides in Australia<ref>Template:Cite journal</ref>
• Takahē into Kahurangi National Park of South Island, New Zealand<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Tasmanian devil in mainland of Australia (ongoing)<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite news</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Toromiro to Easter Island<ref>Template:Cite journal</ref>
• Woylie in Australia (ongoing)

South America

File:Liberación de tortugas en Santiago del Estero - 2.jpg

A Chaco tortoise being released into the wild in Santiago del Estero, Argentina.

• Andean condor in Colombia<ref>Template:Cite news</ref>
• Collared peccary in Iberá Provincial Reserve, Argentina<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Giant anteater in Corrientes, Argentina<ref>Template:Cite news</ref>
• Giant otter to Iberá Provincial Reserve, Argentina<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Golden lion tamarin in the Atlantic Forest of Brazil<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Guanaco in central Argentina
• Jaguar into Iberá Wetlands, Argentina<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Orinoco crocodile into Tomo River in El Tuparro National Park, Columbia<ref>Template:Cite journal</ref>
• Patagonian huemul into Huilo Huilo Biological Reserve in Chile<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• Red-and-green macaw to Iberá Provincial Reserve, Argentina<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• South American tapir into Atlantic Forest of Brazil<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

• Vinaceous-breasted amazon to Parque Nacional das Araucárias, Santa Catarina, Brazil (ongoing)

See also

• De-extinction
• Ecological experiments
• Oostvaardersplassen
• Pleistocene Park
• Pleistocene rewilding
• Reintroduction of wolves
• Rewilding Britain
• Rewilding (conservation biology)
• Rewilding Institute
• Translocation (wildlife conservation)
• Wildlife conservation
• Wildlife management
• World Conservation Union (IUCN)

Further reading

• Armstrong, D, Hayward, M, Moro, D, Seddon, P 2015. Advances in Reintroduction Biology of Australian and New Zealand Fauna, CSIRO Publishing, Template:ISBN
• Gorbunov, Y.N., Dzybov, D.S., Kuzmin, Z.E. and Smirnov, I.A. 2008. Methodological recommendations for botanic gardens on the reintroduction of rare and threatened plants Botanic Gardens Conservation International (BGCI)
• Shmaraeva, A. and Ruzaeva, I. 2009. Reintroduction of threatened plant species in Russia BG Journal, Vol. 6, No. 1

External links

• IUCN/SSC Re-introduction Specialist Group
• IUCN/SSC Re-introduction Specialist Group's NEWSLETTER: "Re-introduction NEWS" (IUCN/SSC)
• Reintroduction of Golden Eagle to Ireland
• BBC News release on Beaver reintroduction in England
• Scottish Beavers Network - campaigning for Beaver reintroduction in Scotland
• Reintroduction of Przewalski's Horse to Mongolia
• Reintroduction of Great Bustard to England
• Reintroduction of Endangered Native Orchids into the Wild in El Valle de Anton, Panama
• Reintroduction of endangered plant species in China: Dipteronia dyeriana, Magnolia odoratissima and M. aromatica, Euryodendron excelsum Chang, Bretschneidera sinensis Hemsl