ASSESSING MINIMUM VIABLE POPULATION-SIZE - DEMOGRAPHY MEETS POPULATION-GENETICS

The discussion of a population's minimum viable size provides a focus for the study of ecological and genetic factors that influence the per sistence of a threatened population. There are many causes of extincti on and the fate of a specific population cannot generally be predicted . This uncertainty has been dealt with in two ways: through stochastic demographic models to determine how to minimize extinction probabilit ies; and through population genetic theory to determine how best to ma intain genetic variation, in the belief that the ability to evolve hel ps buffer a population against the unknown. Recent work suggests that these two very different approaches lead to very similar conclusions, at least under panmictic conditions. However, defining the ideal spati al distribution for an endangered species remains an important challen ge.