They can destroy the ecosystem or out - compete a native species.
Explanation:
For example, if an invasive species of tree is taller than the native species of tree and therefore takes up more sunlight, leaving the shorter native tree not enough sun, then it will effectively kill the native tree.
Also non - native and invasive are not the same thing. A non - native species doesn't necessarily mean it's invasive. It is only invasive if it begins to have a significant impact on the ecosystem it is inhabiting.
