Why are non-native species dangerous to ecosystems?

Answer & explanation:

Non-native species may be animals, plants or microorganisms introduced into an ecosystem of which they are not originally part, but where they adapt and come to dominate, harming natural processes and native organisms.

When a new species is introduced into an environment other than its own, it may compete with others, prey heavily on some species, over-breed and even cause disease.

Therefore, it can be concluded that this action may cause the destruction of some species, directly affecting the balance of that ecosystem.