Applied Ecology/Breeding and Reintroduction of Rare Species



'Species re-introduction' is a process to establish a plant or animal in an area which was once part of its historical range, but from which it has been extirpated or become extinct. 'Species re-establishment' is a synonym, which usually implies that the re-introduction has been successful. The term translocation is used to describe the deliberate and mediated movement of wild individuals or populations from one part of their range to another. Reinforcement or supplementation means the addition of individuals to an existing population.

'Benign introduction' is a process to establish a species, for the purpose of conservation, outside its recorded distribution but within an appropriate habitat and eco-geographical area.

Zoos, aquaria, marine parks, insect houses, botanical gardens - all have their role to play in captive breeding of plants and animals to provide stocks for reintroductions, be it by actually conducting captive breeding, or providing expertise and help. It is estimated that there are about 500,000 animals in captivity in zoos throughout the world. However, it is widely believed that for best results, captive breeding must be done with minimum human contact. The survival of up to 60,000 plant species - about a quarter of the world's total - will be threatened over the next few decades by population growth, deforestation, habitat loss, destructive development and agricultural expansion. Human survival is threatened by the destruction of plants on such a massive scale. In addition to the small number of crop plants we use for our basic food, many wild plants also have great economic importance, providing food, fuel, clothing and shelter for hundreds of millions of people throughout the world. Plants also supply medicines, especially in developing countries where vast numbers depend on wild plants for their traditional remedies. Plants also help maintain the planet's environmental balance and ecosystem stability and provide habitats for the world's animal life.

Botanical Gardens

Cibodas Botanical Garden in Java, Indonesia

There are about 1,600 botanic gardens in the world. They grow tens of thousands of plant species between them; probably as much as a quarter of all the world's flowering plants and ferns are in their collections. The increasing rate of the loss of plant diversity and wild habitats worldwide has encouraged many botanic gardens to become important conservation centres.

In many countries, botanic gardens are amongst the leading, and sometimes the only, institutions involved in or capable of undertaking extensive work in wild plant research and conservation. Many new botanic gardens are being opened or developed to act as centres for plant conservation, study and education, particularly of plants native to their own regions.

Botanic gardens can be defined as public gardens which maintain collections of live plants mainly for study; for scientific research, conservation or education. Many different types of botanic gardens occur, large and small. While their size and resources varies hugely, botanic gardens are united in the belief of the important role that they must play in preserving the world's plant diversity.

  • Botanical gardens grow large collections of endangered plants, holding them safely in cultivation or seed banks in case wild populations are destroyed.
  • They reintroduce plants back to wild as part of species recovery projects.
  • They undertake botanical research to document and record the plants of the world and their characteristics. For example, their collections of dried plants (herbaria) contain millions of specimens as a permanent global reference on plant diversity.
  • They promote environmental awareness amongst the general public through their education work. Globally, botanic gardens receive more that 150 million visitors each year.
  • They are expert centres for horticulture and training; knowing how to grow a plant may be a key to its future survival.

Zoos and Other Institutions for Animal Breeding


A commonly stated aim of many captive breeding programmes conducted in zoological parks is to produce founder populations for release into the wild in reintroduction programmes. Not many zoos possess the know-how for seriously managing captive populations, though that is a situation that is rapidly changing. With new technology, like molecular and DNA analysis, species management has become easier and helps scientists avoid potential pitfalls. For example, mapping genealogical information also helps minimising inbreeding.

Policy guidelines have been drafted by the Re-introduction Specialist Group of the International Union for the Conservation of Nature and Natural Resources (IUCN) in response to the increasing occurrence of re-introduction projects worldwide, and consequently, to the growing need for specific policy guidelines to help ensure that the re-introductions achieve their intended conservation benefit, and do not cause adverse side-effects of greater impact.

These guidelines are intended to act as a guide for procedures useful to re-introduction programmes and do not represent an inflexible code of conduct. Many of the points are more relevant to re-introductions using captive-bred individuals than to translocations of wild species. Others are especially relevant to globally endangered species with limited numbers of founders. Each re-introduction proposal should be rigorously reviewed on its individual merits. It should be noted that re-introduction is always a very lengthy, complex and expensive process. The following sections which illustrate the requirement to integrate ecological knowledge with re-introduction, have been taken from the guidelines.

Aims and objectives


The principal aim of any re-introduction should be to establish a viable, free-ranging population in the wild, of a species, subspecies or race, which has become globally or locally extinct, or extirpated, in the wild. It should be re-introduced within the species' former natural habitat and range and should require minimal long-term management.

The objectives of a re-introduction may include: to enhance the long-term survival of a species; to re-establish a keystone species (in the ecological or cultural sense) in an ecosystem; to maintain and/or restore natural biodiversity; to provide long-term economic benefits to the local and/or national economy; to promote conservation awareness; or a combination of these.

A re-introduction requires a multidisciplinary approach involving a team of persons drawn from a variety of backgrounds. As well as government personnel, they may include persons from governmental natural resource management agencies; non-governmental organisations; funding bodies; universities; veterinary institutions; zoos (and private animal breeders) and/or botanic gardens, with a full range of suitable expertise. Team leaders should be responsible for coordination between the various bodies and provision should be made for publicity and public education about the project.


(i) Feasibility study and background research

An assessment should be made of the taxonomic status of individuals to be re-introduced. They should preferably be of the same subspecies or race as those which were extirpated, unless adequate numbers are not available. An investigation of historical information about the loss and fate of individuals from the re-introduction area, as well as molecular genetic studies, should be undertaken in case of doubt as to individuals' taxonomic status. A study of genetic variation within and between populations of this and related taxa can also be helpful. Special care is needed when the population has long been extinct.

Detailed studies should be made of the status and biology of wild populations(if they exist) to determine the species' critical needs. For animals, this would include descriptions of habitat preferences, intraspecific variation and adaptations to local ecological conditions, social behaviour, group composition, home range size, shelter and food requirements, foraging and feeding behaviour, predators and diseases. For migratory species, studies should include the potential migratory areas. For plants, it would include biotic and abiotic habitat requirements, dispersal mechanisms, reproductive biology, symbiotic relationships (e.g. with mycorrhizae, pollinators), insect pests and diseases. Overall, a firm knowledge of the natural history of the species in question is crucial to the entire re-introduction scheme.
The species, if any, that has filled the void created by the loss of the species concerned, should be determined; an understanding of the effect the re-introduced species will have on the ecosystem is important for ascertaining the success of the re-introduced population.
The build-up of the released population should be modelled under various sets of conditions, in order to specify the optimal number and composition of individuals to be released per year and the numbers of years necessary to promote establishment of a viable population.
A Population and Habitat Viability Analysis will aid in identifying significant environmental and population variables and assessing their potential interactions, which would guide long-term population management.
(ii) Previous Re-introductions
Thorough research into previous re-introductions of the same or similar species and wide-ranging contacts with persons having relevant expertise should be conducted prior to and while developing re-introduction protocol.
(iii) Choice of release site and type
Site should be within the historic range of the species. For an initial re-inforcement there should be few remnant wild individuals. For a re-introduction, there should be no remnant population to prevent disease spread, social disruption and introduction of alien genes. In some circumstances, a re-introduction or re-inforcement may have to be made into an area which is fenced or otherwise delimited, but it should be within the species' former natural habitat and range.
A conservation/ benign introduction should be undertaken only as a last resort when no opportunities for re-introduction into the original site or range exist and only when a significant contribution to the conservation of the species will result.
The re-introduction area should have assured, long-term protection (whether formal or otherwise).
(iv) Evaluation of re-introduction site
Availability of suitable habitat: re-introductions should only take place where the habitat and landscape requirements of the species are satisfied, and likely to be sustained for the for-seeable future. The possibility of natural habitat change since extirpation must be considered. Likewise, a change in the legal/ political or cultural environment since species extirpation needs to be ascertained and evaluated as a possible constraint. The area should have sufficient carrying capacity to sustain growth of the re-introduced population and support a viable (self-sustaining) population in the long run.
Identification and elimination, or reduction to a sufficient level, of previous causes of decline: could include disease; over-hunting; over-collection; pollution; poisoning; competition with or predation by introduced species; habitat loss; adverse effects of earlier research or management programmes; competition with domestic livestock, which may be seasonal. Where the release site has undergone substantial degradation caused by human activity, a habitat restoration programme should be initiated before the re-introduction is carried out.
(v) Availability of suitable release stock
It is desirable that source animals come from wild populations. If there is a choice of wild populations to supply founder stock for translocation, the source population should ideally be closely related genetically to the original native stock and show similar ecological characteristics (morphology, physiology, behaviour, habitat preference) to the original sub-population.
Removal of individuals for re-introduction must not endanger the captive stock population or the wild source population. Stock must be guaranteed available on a regular and predictable basis, meeting specifications of the project protocol.
Individuals should only be removed from a wild population after the effects of translocation on the donor population have been assessed, and after it is guaranteed that these effects will not be negative.
If captive or artificially propagated stock is to be used, it must be from a population which has been soundly managed both demographically and genetically, according to the principles of contemporary conservation biology.
Re-introductions should not be carried out merely because captive stocks exist, nor solely as a means of disposing of surplus stock.
Prospective release stock, including stock that is a gift between governments, must be subjected to a thorough veterinary screening process before shipment from original source. Any animals found to be infected or which test positive for non-endemic or contagious pathogens with a potential impact on population levels, must be removed from the consignment, and the uninfected, negative remainder must be placed in strict quarantine for a suitable period before retest. If clear after retesting, the animals may be placed for shipment.
Since infection with serious disease can be acquired during shipment, especially if this is intercontinental, great care must be taken to minimize this risk.
Stock must meet all health regulations prescribed by the veterinary authorities of the recipient country and adequate provisions must be made for quarantine if necessary.
(vi) Release of captive stock
Most species of mammal and birds rely heavily on individual experience and learning as juveniles for their survival; they should be given the opportunity to acquire the necessary information to enable survival in the wild, through training in their captive environment; a captive bred individual's probability of survival should approximate that of a wild counterpart.
Care should be taken to ensure that potentially dangerous captive bred animals (such as large carnivores or primates) are not so confident in the presence of humans that they might be a danger to local inhabitants and/or their livestock.
Re-introductions are generally long-term projects that require the commitment of long-term financial and political support.
Socio-economic studies should be made to assess impacts, costs and benefits of the re-introduction programme to local human populations.
A thorough assessment of attitudes of local people to the proposed project is necessary to ensure long term protection of the re-introduced population, especially if the cause of species' decline was due to human factors (e.g. over-hunting, over-collection, loss or alteration of habitat). The programme should be fully understood, accepted and supported by local communities.
Where the security of the re-introduced population is at risk from human activities, measures should be taken to minimise these in the re-introduction area. If these measures are inadequate, the re-introduction should be abandoned or alternative release areas sought.
The policy of the country to re-introductions and to the species concerned should be assessed. This might include checking existing provincial, national and international legislation and regulations, and provision of new measures and required permits as necessary.
Re-introduction must take place with the full permission and involvement of all relevant government agencies of the recipient or host country. This is particularly important in re-introductions in border areas, or involving more than one state or when a re-introduced population can expand into other states, provinces or territories.

If the species poses potential risk to life or property, these risks should be minimised and adequate provision made for compensation where necessary; where all other solutions fail, removal or destruction of the released individual should be considered. In the case of migratory/mobile species, provisions should be made for crossing of international/state boundaries.

(i) Planning, preparation and release stages
Approval of relevant government agencies and land owners, and coordination with national and international conservation organizations.
Construction of a multidisciplinary team with access to expert technical advice for all phases of the programme.
Identification of short- and long-term success indicators and prediction of programme duration, in context of agreed aims and objectives.
Securing adequate funding for all programme phases.
Design of pre- and post- release monitoring programme so that each re-introduction is a carefully designed experiment, with the capability to test methodology with scientifically collected data. Monitoring the health of individuals, as well as the survival, is important; intervention may be necessary if the situation proves unforseeably favourable.
Appropriate health and genetic screening of release stock, including stock that is a gift between governments. Health screening of closely related species in the re-introduction area.
If release stock is wild-caught, care must be taken to ensure that: a) the stock is free from infectious or contagious pathogens and parasites before shipment and b) the stock will not be exposed to vectors of disease agents which may be present at the release site (and absent at the source site) and to which it may have no acquired immunity.
If vaccination prior to release, against local endemic or epidemic diseases of wild stock or domestic livestock at the release site, is deemed appropriate, this must be carried out during the "Preparation Stage" so as to allow sufficient time for the development of the required immunity.
Appropriate veterinary or horticultural measures as required to ensure health of released stock throughout the programme. This is to include adequate quarantine arrangements, especially where founder stock travels far or crosses international boundaries to the release site.
Development of transport plans for delivery of stock to the country and site of re-introduction, with special emphasis on ways to minimize stress on the individuals during transport.
Determination of release strategy (acclimatization of release stock to release area; behavioural training - including hunting and feeding; group composition, number, release patterns and techniques; timing).
Establishment of policies on interventions (see below).
Development of conservation education for long-term support; professional training of individuals involved in the long-term programme; public relations through the mass media and in local community; involvement where possible of local people in the programme.
The welfare of animals for release is of paramount concern through all these stages.
(ii) Post-release activities
Post release monitoring is required of all (or sample of) individuals. This most vital aspect may be by direct (e.g. tagging, telemetry) or indirect (e.g. spoor, informants) methods as suitable.
Demographic, ecological and behavioural studies of released stock must be undertaken.
Study of processes of long-term adaptation by individuals and the population.
Collection and investigation of mortalities.
Interventions (e.g. supplemental feeding; veterinary aid; horticultural aid) when necessary.
Decisions for revision, rescheduling, or discontinuation of programme where necessary.
Habitat protection or restoration to continue where necessary.
Continuing public relations activities, including education and mass media coverage.
Evaluation of cost-effectiveness and success of re- introduction techniques.
Regular publications in scientific and popular literature.

Disease Transmission · Environmental Valuation

Disease Transmission · Applied Ecology · Environmental Valuation

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Conservation Management · Habitat Creation · Agro-Ecological Systems · Wetland Engineering · Disease Transmission · Breeding and Reintroduction of Rare Species · Environmental Valuation · Nature Tourism · The Endangered Resources · New Societies and Cultures · Case Studies · Asian Rainforest Politics · British Limestone Grasslands