CAPTIVE BREEDING OF WILDLIFE
Across the world many species of animal and plant are declining at a rapid rate. The loss of habitat is considered the leading cause of species decline. The International Union for the Conservation of Nature (IUCN) predicts that only 3% of the earth's surface is designated for the protection of wildlife. As more animals are added to the endangered species list each year and habitat is being rapidly destroyed alternatives are needed to ensure these species do not become extinct in the wild management option to conserve these populations is to establish and maintain captive populations in ex-situ (outside of their natural habitat). This is where zoos and fauna sanctuaries can become involved. These establishments can play a large role in captive breeding programs as they have the facilities to house significant animals in a benign environment.
Captive breeding is the practice of breeding animals in a human-controlled environment as a tool for conservation. It has been a popular management option for endangered species in recent years as animal populations can increase more rapidly than in the wild. Reproduction experts are continually improving techniques for captive breeding. These improvements mean that there are larger populations of endangered species in captive environments. However, it is important to be aware that captive breeding alone cannot be relied upon to ensure the long-term survival of endangered species.
Captive breeding will not be successful if habitat conservation measures for the species are not in place. There is no point breeding an endangered species in zoos for introduction or reintroduction if the habitat is not available for the species.
Habitat degradation and fragmentation are also issues that need to be addressed. While it may seem that there is habitat available for an animal, it may be of poor quality and not capable of supporting a breeding population.
Successful captive breeding programs need to be matched with successful introduction and/or reintroduction strategies. Wildlife Biologists must understand how an endangered species uses its habitat and how they interact with each other in the wild. Sadly, the reintroduction of these captive populations into natural habitats is not always successful. Due the small founder (initial) populations, many individuals in these populations become inbred and therefore their level of fitness is reduced. This means that they are less likely to survive in the wild.
Goals of Captive Breeding
According to the Smithsonian Conservation Biology Institute, the main goal of most captive breeding programs for endangered species is to establish captive populations that are large enough to be demographically stable and genetically healthy.
Over 500 species
and subspecies of animals are bred in captivity in the US alone. Captive breeding is generally undertaken when a species has reached critical population levels where risk of extinction is likely.
These programs are usually undertaken with the following goals:
- Maintain a healthy age structure (demographics) within the population
- Ensure that reproduction is successful
- Protect the population against disease
- Preserve the gene pool to avoid problems of inbreeding
- Provide animals to re-establish or restock wild populations when needed
Breeding programs can have different aims depending on the species, environment it will be reintroduced to and foreseeable threats on release. The benefits of captive breeding programs are that they can allow for the temporary growth of a population in a stable and low risk environment. This environment provides food supplements, expert health care, reduced exposure to parasites and disease and the removal of predators and other threats.
One of the problems with breeding threatened species in such a benign environment is that they may undergo evolutionary changes in ways that compromise their fitness in the wild. Captive populations may encounter different genetic problems in
captivity influenced by their conditions. These can include:
Higher level of inbreeding due to small founder population
The favouring of harmful mutations through genetic drift
Loss of genetic diversity
Genetic adaptations to captive conditions rather than natural conditions
Issues with Captive Breeding
For good reason, captive breeding for the purposes of conservation is under continued scrutiny. Wildlife biologists and zoo staff are constantly facing issues with captive breeding. Some of these are mentioned below.
Captive breeding programs are generally not initiated until population numbers in the wild have fallen below sustainable levels. This means that the genetic diversity of captive populations is likely to be low.
The species must be able to survive once it is released into its natural habitat. The longer it is in captivity, the less likely it is
to survive in the wild.
Learned and innate (natural) behaviours will influence survival on reintroduction. Some species (such as the Golden Lion Tamarin) need to be given the opportunity to spend time with older animals to learn skills they will need to survive.
Captive breeding programs can be quite expensive. For example, researchers reported that the cost of keeping African Elephants and Black Rhinos in captivity is 50 times higher than maintaining the same population sizes in national parks in Zambia.
Some species are very difficult to breed in captivity due to their natural behaviours. For example, migratory birds and fish that are
highly mobile are extremely difficult to breed in captivity.
Captive breeding programs tend to have species bias. Although many animal species are endangered worldwide, mammal species tend to be favoured for captive breeding programs.
Develop captive breeding programs with the purpose of contributing to the survival and recovery of the species in the wild.
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