Answer :

If herbivores were removed from the ecosystem then the ecosystem wouldn't be equal or it wouldn't be balanced because the ecosystem needs balance to keep it in place and also if no herbivores (which some animals are) then Omnivores or Carnivores can't eat animals that are herbivores which makes COULD carnivores extinct due to no herbivores but carnivores could eat other carnivores just saying. The ecosystem needs right amount of things so it can be balanced..