Ex situ conservation is a complementary approach which offers insurance against these threats to species. It has some useful advantages. Most important of these is that it represents an efficient and cost effective way of conserving the variation within individual species because germ banks occupy little space, and they require little attention over considerable periods of time. In addition, due to the portable nature of such samples, their storage can easily be duplicated in different places with the result that they are less vulnerable to catastrophes.