The food runs out and the species usually ends up running out of food, but can sometimes spread to farther places if they are habitable. Then, that plant is endangered or extinct in that area. That is why overpopulation is taken so seriously. They can damage so many things. Then, the predators will have nothing to eat in that environment and will end up dying and the other animals that eat that plant will end up dying, and so on. Very sad! :(
Thanks for the opportunity to answer your question and I hope this helped! :)