kengr

Infestations aren't the sort of thing that would qualify as an environment. Or at least that doesn't quite fit.

Something that manages to survive outside the "domes" would be a real problem.

Why do I suddenly see Greenpeace types trying to smuggle in organisms that could establish a "native" ecosystem?

Hmm. That'd mean there'd be other "environmentalists" trying to stop them, because the organisms would be "despoiling" the native (lack of) ecosystem worse than the colonists are.