These aren't even concerns limited to genetic engineering. There was a good (if memory serves) Radiolab story ages ago about the conservation efforts on the Gal

These aren't even concerns limited to genetic engineering. There was a good (if memory serves) Radiolab story ages ago about the conservation efforts on the Galapagos islands. The relevant part is that Lonesome George's genome died out with him, and as a result there aren't any tortoises left that can fill the fauna niche on his island of origin. But since the tortoises on other islands are closely genetically related (even given the separation between them), ecologists started a multi-generational breeding program to attempt to select the key traits of Lonesome George's strain so they can introduce a new population to the island that will do the same job his lineage did in the food web. ... which begs the question: when you're doing Bene-Gesserit-style eugenics on tortoises to get the perfect specimens, what's the nature of the nature you're trying to preserve? Humans cannot interact with the natural world without changing it, because it is the nature of life (and human life in particular) to change things. The question isn't how we don't make an impact; it's how do we manage that impact responsibly? (I have no idea if breeding dire-wolf-alikes with genetic modification is responsible or not. Let me know if they get out of the lab and become an invasive species, I think).