I'm hearing that there is a concern about "invasive species" getting a hold over here that used to live in Japan.

I wonder how they can be considered as "invasive species" if they packed up and moved over via a natural event. Is that not au naturel?
I'm not referring to the boats, motorcycles, houses, and plastic grocery bags that floated across the ocean with illegal aliens, but the beach logs and kelp and other such floating things not man-made. Since they also carry the dreaded neighbor's creatures, are they not a natural result of a changing environment and wouldn't they have arrived here even if no humans were around?

just wondering where the line is........