The existing system of protected areas, national parks, sanctuaries and biosphere reserves has many pit-falls for the survival of species which are limited in distribution.
There may not be sufficient habitats and the possibility of finding new habitats of adequate size maybe remote. Many protected areas and habitats are too small and subject to frequent changes to sustain the viable populations of species they seek to preserve.
As human enterprise expands and wildlife habitats shrink numerous life forms will be lost. Large land vertebrates which come in conflict we man shall be ultimately confined to wild life preserves. Whatever we do species shall continue to disappear and biosphere shall continue to lose its constituents one after the other in near future.
With wild life failing to survive in protected areas and natural habitats, conservation under human care appears to be the only solution. No doubt it is impossible to preserve all of the species thus affected but prudence demands that we should intensify our efforts for ex-situ conservation as well since it shall save at least some of the fragments of once extensive wild life for the future.