METHODS OF EX-SITU CONSERVATION:
The practice of ex-situ conservation involves techniques which are essentially meant to maintain, multiply or help the species to survive under natural conditions. These include:
1. Long Term Captive Breeding
The method involves capture, maintenance and breeding in captivity on long term basis of individuals of the endangered species. Captive breeding and propagation on long term basis is usually under taken for species which have lost their habitats permanently or there are present certain such factors in the habitat which shall force it to extinction again.
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In majority of cases where human interests-such as poaching, excessive hunting etc. – come in direct conflict with existence of the species long term maintenance and breeding in captivity is resorted to.
Our zoos and botanical gardens house a number of such animals and plants which are regularly bred in captivity. Most of the species shall not survive in their wild habitats. Captive breeding and maintenance is the only way to preserve such species.
A small herd was, however, maintained in Imperial Hunting Park in Peking, China. It was from this herd that Abbe Armond David procured a pair by bribing the sentinel. The last animal of the Imperial herd died in 1920.
It is from Abbe Armond David’s pair that the species survives today. Nearly 400 specimens of the species are in various zoos of the world where they are maintained and multiplied regularly. The species cannot survive in its original habitats in northern China which is now occupied by sprawling agricultural fields and industries.
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2. Short Term Propagation and Release
Short term maintenance, captive “breeding followed by release of the animal in their natural habitat is a method which is usually resorted to when the population of a species declines due to some temporary set-back in their living conditions there is no irreversible change in the habitat and the animal concerned can survive in its natural home after the factors causing the set back are eliminated. For example, if the decline in the population of the species is due to over hunting, it may be banned by law. The endangered animal maintained and bred in captivity under human care is subsequently released in the wild habitat. Thus a little help enables the species to re-establish itself in its natural home.
3. Animal Reintroduction
Animal reintroduction involves release of animals either borne in captivity or caught in infancy ” from the .wild and grown in captivity, into an area from which they have either declined or disappeared is a result of human pressures (such as hunting) or due to some natural causes (like an epidemic). These introductions may also involve rehabilitation of the species as well.
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The process of training naive animals to live in their natural habitats is referred to as rehabilitation. Rehabilitation is a very important step in the reintroduction procedure involving intelligent animal such is Primates in which learning plays an important role in the development from infancy to adulthood.
It is for purpose of reintroduction of the animal that enormous efforts and expenditure involved in active breeding are accepted by the Society. Indeed many of reintroduction efforts have been fruitful, we agree that natural selection cannot be simulated in ex-situ populations and for all practical purposes ex-situ conservation leads to domestication and disappearance of wild genes.
However, ex-situ care of breeding populations can effectively serve as means to conserve unique or useful traits rather than the entire species as such. Individuals with a set of useful genes can be maintained in captivity for those genes only. We may let the captive population suffer all the adverse consequences which follow when the species is kept imprisoned for long periods of time.
As long as the useful genes persist the individuals of the population are useful to us. These genes may be used to improve domesticated organisms and even the wild ones which are threatened because of the loss of wild genes may be compensated by these preserved genes. Thus ex-situ conservation offers an additional means to conserve the threatened in-situ populations as well.