Running bamboo is notoriously fast spreading and difficult to remove. What keeps its population balanced in the wild, and prevents it from crowding out the competition? I tried googling, but was inundated with gardening advice, horror stories, and assault / offensive gardening (some of the latter two presumably covering the same incident from both sides). My google-fu failed, I couldn’t really find any info about natural population controls of running bamboo in the thicket of tall tales and gardening advice.
If you broaden your question only slightly from bamboo to bamboo and its close relatives, then it has taken over the world. It’s in the grass family, and in no small part thanks to humans, it’s literally everywhere.