When you speak of these small populations, there are several rules of thumb for genetic variation which indicate that a genetic effective population of about 500 (that translates to a census figure of about 2,000 adults), is about the number necessary for a population to maintain long term viability. So a population of 2,000 Grizzly Bears would be secure from the effects of genetic and demographic stochasticity for probably more than a thousand years. If these populations were scattered over a wide geographic range, there would be less danger from environmental stochasticity.

In fact, of all the species, (although there are more chickens than there are humans on earth as Dr. Roopnarine mentioned this morning); humans are about the weediest species on earth. We're about as immune from extinction as you can get because we've got all the habitats covered, wešre spread out all over the globe, and we've got a very large population. But that's not true for Grizzly Bears.

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