A research suggests that an invasive species of midge has the potential to drastically alter Antarctic ecosystems that have been isolated for millions of years. That species of midge was well-suited to thrive in the extreme conditions and has managed to release large volumes of nutrients into the soil, changing the way native species live and evolve. 
But when is a species “foreign”? When does it start being “native”? Isn’t a species automatically “native” from the moment is breaks foot onto the new ecosystem?!? Or is there a “trial period”?
Categorizations are in our mind. And our mind is too limited to understand Nature as One…