If the herbivores are removed from the ecosystem, there will be no food for carnivores which are dependent on herbivores for their survival. As a result, the population of carnivores will also start dwindling. This will lead to ecological instability.

2. When most large herbivores are lost, the effects on the environment can be dramatic and cascading because: Large herbivores shape ecosystems by creating paths to water sources, and smaller species follow their tracks.

“While top predators are undeniably important to ecological function, this new study shows that large herbivores can also play critical roles.”

They would starve and die unless they could move to another habitat. All the other animals in the food web would die too, because their food supplies would have gone. The populations of the consumers would fall as the population of the producer fell.

Primary producers use energy from the sun to produce their own food in the form of glucose, and then primary producers are eaten by primary consumers who are in turn eaten by secondary consumers, and so on, so that energy flows from one trophic level, or level of the food chain, to the next.

If there were no carnivores, the herbivore populations would explode and they will rapidly consume large amounts of plants and fungi, growing until there is not enough food to sustain them. Eventually, the herbivores would starve, leaving only those plants that were distasteful or poisonous to them.

If all the carnivores are removed from the earth, the population of herbivores, will increase. As a result, all plants will disappear from the earth surface and ultimately the earth may become a desert. The biosphere will get disturbed which will lead to end of life on earth.

If you are talking about the Human Being omnivores, the planet would be saved. The pollution would end, the cruelty to billions of animals being constantly slaughtered would end, the excess carbon from all the gasoline and fuel being burned would end, and the climate would recover to where it should be.