Re: Fp. robertsoni

["Catherine Carney" <schmidtcarney at ecr_net>]

>
> These conclusions appear to ignore some basic principles of population
> biology, particularly the fact that for a population to be stable and self
> sustaining it must be of a  reasonable size and dispersion to be able to
> survive temporary setbacks, particularly to small portions of the total
> population. Hence, if the population is so small and restricted that
> elimination of one pond leads to extinction, it was doomed already.
> Sometime in the next 500 years  an exceptional drought was going to dry
> THAT pond up.

Then how do you explain the survival of the Devil's Hole Pupfish? According
to what I have heard and read, the population did not start to crash until
humans started pumping water out of the aquifer which supports its desert
spring. The same is likely true for many other pupfishes which have isolated
ranges (the springs in an otherwise arid environment) and other fish (Nothos
in Africa come to mind). Just because a species has a limited range does not
mean it was automatically headed for extinction, but rather that it occupies
an extremely specialized niche in an often challenging habitat.

Catherine


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