Keystone species come in many shapes and sizes. Some are big (grizzly bears), some are small (starfish), and some are actually vegans (elephants). But there’s one thing they all have in common: Remove them, and the effects will trickle down through the entire ecosystem in which each live. Nature is more than a collection of many autonomous, individual species — it’s an immense, interconnected community. Learn more about keystone species and the various roles they play in this piece from wildlife biologist and author Douglas H. Chadwick.