Producers are the basis for the food chain, so if you just get rid of one producer, herbivores would most likely find another food source. But if you got rid of all of them, no other animals would survive because herbivores have no producers to eat, so they would die, and carnivores would have no herbivores to eat so they would die as well. I’m assuming that scavengers would live though, because they feed off dead animals, and there would be plenty of those if this scenario actually happened