Fair enough genetic conservation is a problem in isolated populations that have evolved independently to some extent, and in this case isolation by distance is most probably the model operating. The populations are too continous to be operating under a metapopulation or island model (historically anyway, no doubt they have become somewhat disjointed since european arrival, although this is hardley an evolutionarily significant timescale in a reasonable sized population), yet the fact that snakes lack the ability to move huge distances unaided means they are less likely to exchange genes with other individuals far away, even though they still maintain they ability to do so (evidenced by intergrades and captive hybridisation). The fact that they are not truely sexually isolated (besides spatially isolated) also brings to bear the thought that they are not even classed as seperate species (under the current biological species concept, nor under the ecological species concept). Its not necessarily my belief, but if you want to go 'by the book' til the death, then thats the way it is. But thats beside the point.........
I looked after native wildlife for 9 years, mainly birds. Birds obviously have the ability to move much further than snakes, but we always released them in the area they were found in, regardless of whether they were permenant resident species or species only temporarily in the area. Some individuals (Torresian pidgeons esp.) had to be maintained in captivity untill the next migration. These animals were ALWAYS released, regularly in national parks (they were often brought to us by parks officials who happily agreed to take care of the release when the time came). Think of it this way, worst case senario:
-if it is introduced into an area it doesn't come from, but which still has a population of Carpets
1) the animals ecological niche is no different, so it will not cause anymore damage to native wildlife than the naturally occuring population.
2) It may introduce a few new genes - if these are unsuited to the conditions, they will be lost though natural selection - if they are well suited, they will most likely already be present and as such no change in heterozygosity levels or gene function will occur. As colour in these animals is so variable already it is pointless worrying about that.
3) pests and diseases - all wildlife carry a heavy parasite load, and it will just come down to Cass not releasing the animal unless it is healthy. Im sure she wouldnt release an unhealthy animal, not after all the work she has put into trying to save it.
I know it is more complicated than that, but I've got a meeting with my supervisor to get to, so.........:?
Rant Over