In ecology : an 'emergency procedure' employed where a species (usually animal, though sometimes plant) is so close to extinction in the wild that the only way to save it is believed to be the capture of one or more breeding pairs, followed by enclosure in some form of zoo or similar institute and an attempt to encourage their reproduction.
The intention is always to increase the total population of the species above a certain 'safety margin' and then to reintroduce it to the wild.
Disadvantages:- Many animal species either breed poorly or fail to breed at all in captivity. (For instance and notoriously, the Giant Panda.)
Advantages:- Where this isn't the case --- for example, the California condor has been bred extremely effectively in captivity --- the offspring produced are often far less liable to accident than they would be in their natural habitat, so that increase can rapidly exceed attrition.
Some animal species being bred in captivity for reintroduction