Answer the
Elaborate how invasion by an alien species reduces the biodiversity of an area.

Explanation

(i) Accidental or intentional introduction of non-native species into a habitat has led to the declination or extinction of indigenous species. Alien species cause decline or extinction of indigenous species. E.g
(i) The Nile Perch introduced in Lake Victoria (East Africa) caused extinction of more than 200 species of native fish, cichlid fish in the lake.
(ii) Invasive weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eicchornia) caused damage to our native species.
(iii) The illegal introduction of the African Catfish (Clarias gariepinus) for aquaculture is posing a threat to the indigenous catfishes in our rivers.