In the great adventure of life on Earth, every species has a role to play, every species has its place. None is futile or harmful. They all balance out. It's like we are all together in our giant home, the Earth. But this beautiful dream broke down when humans entered into this paradise. Before there existed a food chain; all animals had a position in this chain - the strongest at the top and the weakest at the bottom. Generally there were larger numbers in the lower levels of the chain, this enabled those at the top to survive. If you are a sensitive person, you will feel pain for the smallest ones but this is the cycle of life, as Darwin said, this is the natural selection, the law of the strongest one.
Species are born to reproduce, this is their main function in life. Any changes to this would be devastating. For thousands of years the food chain has remained balanced - everything had its place. Until humans entered and developed. Look at the case of Australia. In that country, rabbits reproduced more than the normal average, so there were a lot and this disturbed the farmers. Therefore the "so called" intelligent scientists decided to use a poison to kill the rabbits, so they died out. In my opinion it's not the solution; neither introduce another animal that's the predator of the other.
If we continue acting in this way, we will wipe out many species in the world because if one species of animal disappears, then their predators also will be in risk of extinction and like this more cases. Maybe we aren't noticing it but we and our foolish mind are at fault of this non balanced out world. So, we have to settle down and start to think reasonably. Because sooner or later we will have to pay the consequences, the ones which would bring such terrible things that we've never seen.