The IUCN and many other organizations and governments maintain databases tracking the status of species. Legislation and international agreements regulate immediate causes of rarity such as exploitation and habitat loss. Preservationist species conservation aims to minimize proximate causes of mortality with measures such as reducing insect herbivory on young Pitcher’s thistles or nest parasitism by cowbirds on Kirtland’s warblers. Intrinsic limits on population growth are managed through interventions such as headstarting marine turtles, replacement clutching and cross-fostering whooping cranes and brush-tailed rock wallabies, removing raptor chicks at risk of fratricide, as well as genetic management combined with captive breeding, reintroduction, and translocation of red kites, brown bears, and California condors. Genetic management of rare populations strives to minimize problems from both inbreeding and genetic swamping. Designations of species as indicators, umbrellas, keystones, or flagships are used to prioritize species for protection and intervention.

This chapter examines the role of zoos in the reintroduction of threatened animals into the wild. Zoos are increasingly involved with reintroduction projects and in-situ conservation. Once a sufficient number of animals have been bred in cooperative breeding programmes, appropriate individuals may be selected for release, and trained to avoid predators and find food and shelter to increase their post-release survival rates. After release they should be monitored for disease and so that survival rates may be determined. In-situ conservation projects may involve zoos providing overseas partners with expertise, training, community education, equipment, funding and other resources to support them in protecting indigenous species and ecosystems. Zoos have played an important role in the recovery of some species by breeding animals for release or providing expertise and other resources to facilitate reintroductions. Many zoos have made significant contributions to in-situ projects to protect threatened species and habitats.

The Eurasian beaver has returned to Britain, presenting fundamental challenges and opportunities for all involved. Beavers will inevitably expand throughout British freshwater systems and provide significant benefits. Unofficial releases have presented challenges in terms of sourcing and genetics, health status and disease risks, the risk of introducing the non-native North American beaver species, and the lack of engagement with communities and resulting conflict. Agreed approaches require development using multi-stakeholder approaches to recognise and promote benefits whilst sensitively managing beavers’ impacts on people’s livelihoods.

The May 2019 IPBES emphasised the scale of the current biodiversity crisis and the need for transformative change, but highlighted that the tools exist to enable this change. Conservation translocation is an increasingly used tool that involves people deliberately moving and releasing organisms where the primary goal is conservation – it includes species reintroductions, reinforcements, assisted colonisations and ecological replacements. It can be complex, expensive, time consuming, and sometimes controversial, but when best practice guidelines are followed it can be a very effective conservation method and a way of exciting and engaging people in environmental issues. Conservation translocations have an important role to play not only in improving the conservation status of individual species but also in ecological restoration and rewilding by moving keystone and other influential species. As the climate continues to change, species with poor dispersal abilities or opportunities will be at particular risk. Assisted colonisation, which involves moving species outside their indigenous range, is likely to become an increasingly used method. It is also a tool that may become increasingly used to avoid threats from the transmission of pathogens. Other more radical forms of conservation translocation, such as ecological replacements, multi-species conservation translocations, and the use of de-extinction and genetic interventions, are also likely to be given stronger consideration within the wider framework of ecological restoration. There have been significant advances in the science of reintroduction biology over the last three decades. However new ways of transferring and sharing such information are needed to enable a wider spectrum of practitioners to have easier access to knowledge and guidance. In the past the biological considerations of conservation translocations have often heavily outweighed the people considerations. However it is increasingly important that socio-economic factors are also built into projects and relevant experts involved to reduce conflict and improve the chances of success. Some level of biological and socio-economic risk will be present for most conservation translocations, but these can often be managed through the use of sensitivity, professionalism, and the application of tried and tested best practice. The role of species reintroduction and other forms of conservation translocations will be an increasingly important tool if we are to restore, and make more resilient, our damaged ecosystems.

Law can influence conservation translocations in two basic ways: it can play a supportive and/or a restrictive role. Regarding the first role, legislation can provide support, a mandate, and/or an obligation to consider or perform a translocation. This may involve both general obligations to conserve or restore certain species or ecosystems, as well as specific obligations concerning species reintroductions or other types of translocation. Regarding the second role, legislation can impose limitations on translocation possibilities and/or make translocations conditional on meeting certain requirements. Such limitations and conditions may follow from legislation on native species protection, area protection, invasive non-native species, disease, trade, animal welfare, and several other areas of law. Requirements of both types may flow from international and national law. The legal requirements that will apply to any projected conservation translocation will depend on the countries, areas, and species involved, and there may be significant differences between one project and the next. The applicable requirements may be easy to meet for some projects, and be prohibitive for others. It is crucial that a careful analysis of applicable domestic legislation is carried out in the early stages of any contemplated conservation translocation. Practitioners should also make themselves aware of the relevant international legislation to provide them with the wider legal context of their work, and to help them influence the development of future legislation.

Between 20 and 40 per cent of plant species are at risk of extinction in the wild worldwide. Conservation translocation is an accepted strategy intended to ensure the conservation of a species in a natural context where it can undergo evolution, usually, but not exclusively, within its historical indigenous range. Because plants are sedentary, practitioners should take care to select an appropriate recipient site, consider the possibility of local adaptation, and choose source material from similar climatic and environmental conditions to the recipient site. As variation increases in a target species’ environment, practitioners should expect greater variation in seed dormancy and timing of germination, and take account of this in the monitoring plan. Prior to translocation, consider the focal species’ dependency on belowground mutualists (e.g. mycorrhizal fungi) and whether recipient sites have appropriate plant-pollinator networks. When selecting founder populations, use as large a founder size as feasible to increase the chance of establishment and survival, and consider the focal species’ life history when choosing propagule stage. If the biology of the focal species is poorly understood and key environmental drivers of translocation success are unknown, use experiments, predictive models, and multiple recipient sites to test hypotheses and improve translocation outcomes. Ensure that threats are known and abated before and after translocation, consider herbivore or predator exclusion, and create a management plan to maintain appropriate habitat conditions or disturbance regimens over the long term. Develop a detailed monitoring and data management plan to track translocated individuals and make sure to account for plant life history, vegetative dormancy, and the potential for lags in next generation seedling recruitment. Translocation success requires long-term commitment, financial and public support, and collaboration among conservation partners.

Long-term monitoring of reintroduced populations may: inform ongoing management decisions for the focal population, such as supplementary feeding or harvesting; make it possible to predict the future viability of small populations, and therefore the need for genetic management; inform site selection for further reintroductions, for example by showing how survival and reproduction rates vary with climatic conditions; facilitate our ability to ability to predict population dynamics at new reintroduction sites, for example by informing values for parameters that can be estimated only from long-term data; and improve our understanding of the dynamics of reintroduced populations, so future monitoring and management can focus on the key factors affecting persistence.

In total, 600 two-year-old and three-year-old saplings of the critically endangered Chinese endemic huagaimu were translocated into the species’ natural range. There were very low survival rates (2 and 20 per cent respectively) of translocated individuals at two sites in Xichou county, with a much higher survival rate of 74 per cent at two sites in Maguan county. The over-riding determinant of translocation success is considered to be the difference in horticultural practices used in the different translocations, with much more favourable outcomes associated with greater horticultural training and expertise.

Although conservation translocations always aim to result in ‘conservation benefit’ for a species or ecosystem, there are many motivations and contexts in which people undertake conservation translocations. Establishing a need for translocations involves considering other ways to deliver the ‘conservation benefit’ to a species or ecosystem. Typically, translocations are initiated alongside other conservation measures. Destination sites must be carefully selected based on more than just vegetation type; attention must be paid to climate, biotic interactions, and other species’ requirements for survival. Socio-economic risks and benefits and legislative constraints should also be considered when evaluating destination sites. Translocated plants, animals, or fungi may be sourced from in situ or ex situ populations, or a combination of the two. Ideally, source populations are those that can support the removal of individuals for translocation without negative consequences for individuals that remain in the wild. It also helps to have ecological similarity between source and destination sites when using wild individuals. Releases should only occur where the original cause of extirpation/decline has been minimised. The choice of one or several sites, and the possibility of several releases over multiple timepoints should be considered, perhaps using pilot releases to evaluate suitability. Monitoring is crucial to being able to report the outcome of the conservation translocation but, perhaps more importantly, allows the translocation team to adapt to changes in status and may prompt the implementation of an exit strategy. Sharing monitoring results is important for others to benefit from lessons learnt. Seek as much advice as you can in the planning phases and build a team that can deliver the various components of the project.

The rewilding concept was born only about 20 years ago as large-scale conservation based on core protected areas linked by corridors, within which top-order predators have been restored. The original vision of rewilding has become somewhat blurred amongst a plethora of projects branding themselves as rewilding. Broadly two types of rewilding can be recognised: trophic rewilding, entailing the active restoration of key species, and passive rewilding, the spontaneous and undirected return of vegetation and ecological processes. Conservation translocations, in the form of reintroduction and ecological replacement, are a key component of trophic rewilding, with the prevalence of reintroductions in rewilding projects increasing in recent years. Trophic rewilding is therefore the intersection between rewilding, conservation translocations, and ecological restoration, where reintroduction or ecological replacement of key species is used to restore lost ecological functions.

Refaunation can be used to restore empty habitat in Atlantic Forests. TNP has suitable habitat for all ongoing reintroductions. At TNP, some plants are only dispersed/consumed by reintroduced species. We need to continue monitoring the recovery of ecological interactions and population establishment.