Yeah no, sorry, saying that rabbits need wolves proves that you don't know how ecosystems actually work. You seem to be confusing "needs" with regulating mechanisms. Or maybe you do know how ecosystems work and you're using sloppy language, but we're on a philosophy oriented forum here so one's terminology used in argumentation has to be spot on in order to leave as much room for misunderstandings as possible or else I don't what we're doing here.