Why it is bad for the environment if humans introduce a new species into a habitat?
Because they may out-compete another existing species and therefore the original species may die or not be as populous. And this could affect alot of other species of plants and animals. For instance, introducing beavers into an area may be bad for trees because beavers gnaw on the trees to cut them down for their dams. This would have an effect on birds living in the trees. Also, predators which may be able to kill a beaver would increase in number because there would be more food to eat, and therefore its original prey would decrease in numbers because the amount of predators would increase, with more sources of prey. So, introducing a new species could potentially kill off a whole species who were originally there or force them to move on to a different area.
