This is an issue of terminology. The terminology we've been using to describe the mountain pine beetle is “native invasive”. Although it's native to B.C., the forests that it's in now—in Alberta—don't have that history with the beetle, so it is behaving a bit like an invasive species on that front. Certainly we can use that terminology, “native invasive”, to describe some of these things that may be native but are spreading into new areas.
Otherwise, in the typical language about invasive species, we think of those as coming in, typically, from overseas. That's the sort of terminology we tend to use.