“Ex-situ” conservation: It means the wild-life conservation in captivity under human care. In this, the endangered plants and animals are collected and bred under controlled conditions in gardens, zoos; sanctuaries etc., wild-life management in captivity have the following advantages:
(i) The organisms are assured of food, water, shelter and security and hence can have longer life span and longer span of breeding activity, thereby increasing the possibility of having number of offspring’s.
(ii) The chances of survival of endangered species increase because of human care under secure conditions.
(iii) This offers the possibility of using genetic techniques to improve the species concerned. However, there are some disadvantages and limitations of wild-life management are captivity:
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(i) Since maintenance and breeding of plants and animals under captivity is very expensive, it can be adopted only for a few selected species.
(ii) Wild-life captivity only under a set of favourable environmental conditions deprives the organisms the opportunity to adapt to ever-changing natural environment. Therefore, new life forms cannot evolve and thus the gene-pool gets stagnant.
Ex-situ conservation, using sample populations, is done through establishment of gene banks which include genetic resource centres, zoo’s, botanical gardens, culture collections etc.
Ex-situ conservation is the chief mode for preservation of genetic resources, which may include both cultivated and wild material. Generally seeds or in-vitro maintained plant cells, tissue and organs are preserved under appropriate conditions for long term’ storage as gene banks. This requires considerable knowledge of the genetic structure of population sampling techniques, methods of regeneration and maintenance of varietal gene pools, particularly in cross pollinated plants.