In-situ conservation of wild life offers many advantages. In fact, the method involves promotion of natural system to take care of its own self - we simply provide conditions to let life forms do it themselves. The advantages of in-situ conservation can be summed up as follows:
(1) In-situ conservation is a cheap and convenient way of conserving biological diversity as we play a supportive role only. Factors detrimental to the existence of the species concerned are eliminated and the species is allowed to grow in its natural environment in which it has been growing since a long time. This reduces the cost of conservation efforts enormously.
(2) In order to ensure the survival of the species we protect the entire natural habitat or the ecosystem. Naturally to protect a population of carnivores there have to be adequate population of herbivores in the system which serves as food for the predators. To maintain the population of herbivores there has to be plenty of green vegetation for the herbivores to feed on.
Thus, a large number of organisms are protected and maintained in the process. The biological wealth of our planet is very imperfectly known to us. By sorting out and protecting a few species in artificial habitats we shall almost certainly leave a large number of life forms which are also as important to us as are those organisms which we are currently trying to preserve and protect. Thus, in-situ conservation offers way to protect to a large number of organisms simultaneously known or unknown to science,
(3) In a natural system organisms not only live and multiply but evolve as well. A natural ecosystem allows free play of natural agencies - like drought, storms, snow, fluctuation in temperatures, excessive rains, fires, pathogens etc. - which provide an opportunity to the organisms to adjust to the prevailing conditions of the environment and evolve into a better adopted life form.
By isolating a species in artificial environment under human care we exclude these agencies and organisms lose chances to adopt themselves to the prevailing conditions. This freezes the vial process of evolution. The germ plasm tends to stagnate. These species which we are protecting today may become useless for us in future as it would not have weathered the adversities of nature during its maintenance under human care.
An important disadvantage of in-situ conservation is that it requires large areas of earth's surface if we have to preserve the full complement of biotic diversity of a region. This involves minimizing or excluding human activity and interference from that locality which is often difficult in the face of growing demand for space. After all humans also need space to live.