Alien species are a threat to native species. Justify taking example of an animal and a plant alien species.

Explanation

The alien species becomes invasive, compete, with the native species and causes extinction of the indigenous species. For example
(i) Parthenium Lantana and Eicchornia are the exotic species of plants that have invaded India and caused enviornment damage, they pose threat to the survival of many of our native species.
(ii) lnroduction of African catfish (Clarias gariepinus) for aquaculture purposes, is posing threat to our indigenous catfish, Clarias bacterachus.