>>35805894Indeed, but the UBs are of a drastically dangerous nature most of the time. Celesteela for example can torch entire forests and suck the water from the surrounding area dry easily, causing plants to wither and die. The Pokemon Mystery Files images show a number of images that depict the power that other UBs can use to inflict harm to the organisms surrounding them.
Destructive foreign species like Yungoos do it on a smaller scale that is more akin to a pest (although Yungoos I recall being based off a severe issue in real life that has caused the extinction of dozens of Hawaiian bird species).
Creatures like Alolan Sandshrew and Ninetales are of the harmless variety and Sandshrew has integrated itself particularly well, becoming food for wild Sneasel.