Any creature, wherever happens to find itself, does its best to flourish and survive to the betterment of its own kind. How successful a creature is as flourishing in non-native habitats is probably a good indicator of its invasiveness in habitats where it is not native. It's not complicated.
To Theo's point, we really can't exclude ourselves. It's only natural to want to flourish. The saga has been going on a very long time, most of that time without us, but we've most certainly accelerated it now that we are here.
